JP6830191B2 - Epoxy resin composition, prepreg, metal-clad laminate and printed wiring board - Google Patents

Description

The present invention relates to epoxy resin compositions, prepregs, metal-clad laminates and printed wiring boards.

Conventionally, semiconductor devices have tended to have higher density, higher integration, and higher speed of operation, and the package form has been shifted from the pin insertion method to the surface mount method, and the size and thickness have been actively reduced.

As a surface mount method, a chip on board (COB) in which a bare chip (semiconductor) is directly mounted on a substrate and connected by wire bonding is widely used (Patent Document 1). In particular, the semiconductor device 100 shown in FIG. 4 is used in situations where bonding reliability and heat resistance of wire bonding are required even when exposed to a high temperature for a long time. The semiconductor device 100 mounts a semiconductor 120 on a ceramic substrate 110 via a joint 130, and uses a gold metal wire (hereinafter referred to as a gold wire 140) to form an aluminum bond pad portion (hereinafter referred to as a gold wire 140) between the semiconductor 120 and the ceramic substrate 110. Hereinafter, it is electrically connected to the aluminum pad portion 111) and sealed with the sealing resin body 150.

In recent years, there has been a tendency to replace the ceramic substrate 110 with a cheaper organic substrate in order to reduce costs.

Japanese Unexamined Patent Publication No. 2008-060309

However, when the semiconductor device 100 in which the ceramic substrate 110 is replaced with an organic substrate is exposed to a high temperature (160 ° C.) environment for a long time (2000 hours), for example, the wire joint portion A between the aluminum pad portion 111 and the gold wire 140 There was a risk that the joint strength would decrease and become insufficient. That is, if the semiconductor device 100 provided with the organic substrate is exposed to a high temperature environment for a long time, there is a possibility that the bonding reliability of the wire bonding between the gold wire and the aluminum pad portion becomes insufficient.

Therefore, an epoxy resin composition, a prepreg, a metal-clad laminate, and a printed wiring can be used as a semiconductor device having excellent bonding reliability of wire bonding between a gold wire and an aluminum pad even when exposed to a high temperature environment for a long time. The purpose is to provide a board.

The epoxy resin composition of the present invention comprises an epoxy resin having a naphthalene skeleton, an organic component containing a curing agent and a curing accelerator, and an inorganic component containing spherical silica particles having an average particle diameter of 1.5 μm or more and 3 μm or less. The butanol content after curing is less than the measurement detection limit by gas chromatography mass (GC-MS) analysis method, the chlorine content after curing is 900 ppm or less, and the bromine content after curing is 900 ppm or less. It is characterized by being 900 ppm or less.

The prepreg of the present invention is characterized by comprising a fiber base material and a semi-cured product of the epoxy resin composition impregnated in the fiber base material.

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 adhered to one side or both sides of the cured product.

According to the present invention, it is possible to obtain a semiconductor device having excellent bonding reliability of wire bonding between a gold wire and an aluminum pad portion even when exposed to a high temperature environment for a long time.

It is the schematic sectional drawing in the thickness direction of the printed wiring board of the semiconductor device which concerns on embodiment of this invention. FIG. 2A is a schematic cross-sectional view of a four-layer staircase daisy chain pattern forming portion of the evaluation substrate used for the thermal shock test, and FIG. 2B is a schematic cross-sectional view of the outer layer daisy chain pattern forming portion of the evaluation substrate used for the thermal impact test. It is a schematic sectional view. FIG. 3A is a schematic front view of a core substrate used in an evaluation test of four-layer plate moldability showing a hollow portion formed in a part of a lattice pattern, and FIG. 3B is an enlarged front view of the P portion in FIG. 3A. Is. It is the schematic sectional drawing in the thickness direction of the ceramic substrate of the conventional semiconductor device.

Hereinafter, embodiments of the present invention will be described.

[Epoxy resin composition according to this embodiment]
FIG. 1 is a schematic cross-sectional view of the semiconductor device 1 according to the present embodiment, cut in the thickness direction of the printed wiring board 10. In FIG. 1, 1 is a semiconductor device, 10 is a printed wiring board, 11 is an aluminum bond pad portion (hereinafter referred to as an aluminum pad portion), 20 is a semiconductor, and 30 is a gold metal wire (hereinafter referred to as a gold wire). , 40 is a bonded body, and 50 is a sealing resin body. In addition, in FIG. 1, the conductor wiring, the through hole, the electronic component for soldering, etc. of the printed wiring board 1 are omitted.

The epoxy resin composition according to the present embodiment (hereinafter, may be simply referred to as an epoxy resin composition) is suitably used as a constituent material of a printed wiring board 10 used in a COB type semiconductor device 1, and is an epoxy resin and cured. Contains organic components including agents and curing accelerators. Further, in the epoxy resin composition, the butanol content after curing is less than the measurement detection limit by the gas chromatography mass (GC-MS) analysis method (hereinafter, may be simply referred to as less than the measurement detection limit), and after curing. The chlorine content of is 900 ppm or less, and the bromine content after curing is 900 ppm or less. As a result, the semiconductor device 1 having excellent bonding reliability of wire bonding between the gold wire 30 and the aluminum pad portion 11 can be obtained even when exposed to a high temperature (160 ° C.) environment for a long time (2000 hours). It is presumed that this is because the number of elements that accelerate the progress of corrosion of the wire joint A between the aluminum pad portion 11 of the printed wiring board 10 and the gold wire 30 has decreased. Corrosion means, for example, the generation of voids. Further, since the printed wiring board 10 can be used instead of the conventional ceramic substrate 110, it is advantageous in terms of cost.

The butanol content after curing is a value measured by the same measuring method as the butanol content measuring method described in the example in which a metal-clad laminate was prepared in the same manner as in the example using the epoxy resin composition. Is. Less than the measurement detection limit means that the value measured by the same measurement method as the method for measuring the butanol content described in Examples is less than 0.16 ppm. The chlorine content after curing is a value measured by the same measuring method as the chlorine content measuring method described in the example in which a metal-clad laminate was prepared in the same manner as in the example using the epoxy resin composition. Is. The bromine content after curing is a value measured by the same measuring method as the bromine content measuring method described in the example in which a metal-clad laminate was prepared in the same manner as in the example using the epoxy resin composition. Is.

The epoxy resin composition has a butanol content after curing, which is less than the detection limit measured by gas chromatography-mass (GC-MS) spectrometry. When the butanol content exceeds the measurement detection limit, even if the chlorine content and the bromine content are within the above ranges, a trace amount of chlorine or bromine contained in the cured product of the epoxy resin composition (hereinafter collectively referred to as halogen). (In some cases), butanol reacts with each other to facilitate the production of halogen. As a result, voids are likely to occur in the wire bonding portion A, and the semiconductor device 1 may have insufficient wire bonding reliability. It is presumed that this is because halobutane enters the inside from the outer peripheral portion of the wire joint A and accelerates the progress of the Kirkendall phenomenon. In particular, when butanol is a linear n-butyl alcohol, a halogen compound is likely to be produced. Even if butanol is not used as a material for constituting the epoxy resin composition, butanol is produced by decomposition of the epoxy resin composition in the process of manufacturing the semiconductor device 1, particularly in the process of curing the epoxy resin composition. Sometimes. Examples of such a material include the product name "XZ92741" manufactured by Dow Chemical Japan Co., Ltd. Here, the Kirkendall phenomenon is a phenomenon in which when two different metals are joined by mutual diffusion, if there is a difference in the intrinsic diffusion coefficient of each material, a void is generated on the material side having a large diffusion coefficient. This phenomenon is especially likely to occur at high temperatures. Examples of halobutane include halogen compounds in which the hydroxyl group of butanol is replaced with a halogen atom.

The epoxy resin composition has a chlorine content of 900 ppm or less, preferably 450 ppm or less, and more preferably 300 ppm or less after curing. The epoxy resin composition has a bromine content of 900 ppm or less, preferably 450 ppm or less, and more preferably 300 ppm or less after curing. When at least one of the chlorine content after curing and the bromine content after curing exceeds 900 ppm, the epoxy resin composition voids the wire bonding portion A even if the butanol content after curing is less than the measurement detection limit. And cracks are likely to occur, and the semiconductor device 1 may have insufficient wire bonding reliability. It is presumed that this is because the halogen derived from this epoxy resin composition enters the inside from the outer peripheral portion of the wire joint portion A, and the halogen acts as a catalyst to accelerate the progress of corrosion of the wire joint portion A. Even if the material constituting the epoxy resin composition is halogen-free, chlorine and bromine may inevitably be mixed in the epoxy resin composition in the process of manufacturing the semiconductor device 1.

In the epoxy resin composition, the total of the chlorine content after curing and the bromine content after curing is preferably 900 ppm or less, more preferably 600 ppm or less. When the total of the chlorine content after curing and the bromine content after curing is within the above range, the semiconductor device 1 can be obtained with excellent bonding reliability of wire bonding even when exposed to a high temperature environment for a long time.

<Organic component>
The epoxy resin composition contains an organic component. As the organic component, an epoxy resin, a curing agent, a curing accelerator, and the like may be further contained, and if necessary, rubber particles, a thermoplastic resin, a thermosetting resin, and the like may be further contained.

(Epoxy resin)
The epoxy resin composition contains an epoxy resin as an organic component. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin and other bisphenol type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin and other novolac type epoxy resin, and biphenyl. Type epoxy resin, xylylene type epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, biphenyl novolac type epoxy resin, biphenyl dimethylene type epoxy resin, trisphenol methane novolac type epoxy resin, tetramethyl biphenyl type epoxy resin, etc. Naphthalene type epoxy resin such as arylalkylene type epoxy resin, tetrafunctional naphthalene type epoxy resin, naphthalene skeleton modified cresol novolac type epoxy resin, naphthalenediol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, methoxynaphthalene modified cresol novolac type epoxy resin, Naphthalene skeleton-modified epoxy resin such as methoxynaphthalenedimethylene type epoxy resin, triphenylmethane type epoxy resin, anthracene type epoxy resin, dicyclopentadiene type epoxy resin, norbornen type epoxy resin, fluorene type epoxy resin and the like can be used. Only one of these may be used, or two or more of these may be used in combination. Among them, it is preferable that the epoxy resin has a naphthalene skeleton, that is, the epoxy resin contains a naphthalene type epoxy resin. As a result, the glass transition temperature (Tg) of the printed wiring board 10 and the metal-clad laminate (hereinafter collectively referred to as the printed wiring board 10 and the like) according to the present embodiment described later is compared with the case where the naphthalene type epoxy resin is not used. Can be higher. Further, the rate of change in resistance of the printed wiring board 10 or the like can be suppressed within ± 5%. The resistance change rate of the printed wiring board 10 or the like is a value measured by the same measuring method as the measuring method of the thermal shock test described in the examples.

The content of the epoxy resin is preferably 75 parts by mass or more and 125 parts by mass or less, and more preferably 85 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the organic component in the epoxy resin composition. Among them, the content of the naphthalene type epoxy resin is preferably 20 parts by mass or more and 70 parts by mass or less, and more preferably 30 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the organic component in the epoxy resin composition. ..

(Hardener)
The epoxy resin composition contains a curing agent as an organic component. As the curing agent, for example, a phenol-based curing agent, an amine-based curing agent, an acid anhydride, an imidazole-based compound, a sulfide resin, a dicyandiamide, or the like can be used. Only one of these may be used, or two or more of these may be used in combination. Among them, it is preferable that the curing agent has a phenol skeleton, that is, the curing agent contains a phenol-type curing agent. This makes it possible to obtain a printed wiring board 10 or the like that is less likely to absorb moisture.

(Curing accelerator)
The epoxy resin composition contains a curing accelerator as an organic component. 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.

<Inorganic component>
The epoxy resin composition may further contain an inorganic component. As the material constituting the inorganic component, for example, silica, boehmite, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, talc, clay, mica and the like can be used. Only one of these may be used, or two or more thereof may be used in combination. The shape of the inorganic component is not particularly limited, and examples thereof include a spherical shape and a crushed shape. The average particle size of the inorganic component is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 2.5 μm or less. Among them, the inorganic component contains spherical silica particles, and the average particle diameter of the spherical silica particles is preferably 0.1 μm or more and 3 μm or less. This makes it possible to obtain a printed wiring board 10 or the like having excellent formability of a four-layer board. The average particle size of the spherical silica particles is preferably 0.1 μm or more and 3 μm or less, and more preferably 0.1 μm or more and 2.5 μm or less. Here, the average particle diameter means the volume cumulative average diameter (D50). For the measurement of the average particle size, for example, a laser diffraction type particle size distribution measuring device MT-3300 (manufactured by Nikkiso Co., Ltd.) can be used.

The content of the inorganic component is preferably 150 parts by mass or more and 220 parts by mass or less, and more preferably 160 parts by mass or more and 210 parts by mass or less with respect to 100 parts by mass of the organic component. As a result, the coefficient of thermal expansion of the printed wiring board 10 and the like can be suppressed to 20 ppm or less. The coefficient of thermal expansion of the printed wiring board 10 or the like is a value measured by the same measuring method as the method for measuring the coefficient of thermal expansion (CTE (α1)) described in the examples.

[Preparation method of epoxy resin composition]
Examples of the method for preparing the epoxy resin composition include a method in which an organic component and other components to be blended as necessary are prepared in a predetermined blending amount, blended in a solvent, and further stirred and mixed. Be done. As the solvent, for example, ethers such as ethylene glycol monomethyl ether, acetone, methyl ethyl ketone (MEK), dimethylformamide, benzene, toluene and the like can be used.

[Prepreg according to this embodiment]
The prepreg according to the present embodiment (hereinafter, may be simply referred to as a prepreg) includes a fiber base material and a semi-cured product of an epoxy resin composition impregnated in the fiber base material.

Since the prepreg comprises a semi-cured product of the epoxy resin composition described above, the butanol content after curing, the chlorine content after curing, and the bromine content after curing of the prepreg include butanol after curing of the epoxy resin composition. It is the same as the amount, the chlorine content after curing, and the bromine content after curing. The method for measuring the butanol content after curing, the chlorine content after curing, and the bromine content after curing of the prepreg is as follows: the butanol content after curing, the chlorine content after curing, and the bromine content after curing of the epoxy resin composition. It is the same as the method for measuring the bromine content of.

As the fiber constituting the fiber base material, for example, glass fiber, aromatic polyamide fiber, liquid crystal polyester fiber, poly (paraphenylene benzobisoxazole) (PBO) fiber, polyphenylene sulfide resin (PPS) fiber and the like can be used. Of these, it is preferable to use glass fiber.

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. As a result, it is possible to obtain a cured product of a prepreg having excellent electrical insulation and dielectric properties.

The surface of the fiber substrate 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 fiber base material 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 fiber base material is preferably 10 to 200 μm.

Examples of the prepreg manufacturing method include a continuous manufacturing method and a batch manufacturing method. In the continuous manufacturing method, a running long fiber base material is impregnated with an epoxy resin composition containing a solvent (hereinafter, may be referred to as varnish) to obtain a resin impregnated base material, and the obtained resin impregnated base material is obtained. This is a method in which the epoxy resin composition is semi-cured by heat-drying and the solvent is removed, and cut into a required size. In the batch method, a fiber base material cut to a required size is impregnated with a varnish to obtain a resin-impregnated base material, and the obtained resin-impregnated base material is heated and dried to remove a solvent to form an epoxy resin composition. This is a method of semi-curing an object. The temperature for heating and drying is preferably 110 ° C. or higher and 150 ° C. or lower.

[Metal-clad laminate according to this embodiment]
The metal-clad laminate according to the present embodiment (hereinafter, may be simply referred to as a metal-clad laminate) may be a cured product of one prepreg or a cured product of a plurality of laminates (hereinafter, referred to as a first insulating layer). There is) and a metal foil adhered to one 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 constituting the metal-clad laminate comprises the cured product of the above-mentioned epoxy resin composition, the butanol content, chlorine content and bromine content of the metal-clad laminate are determined after the epoxy resin composition is cured. Butanol content, chlorine content after curing, and bromine content after curing are the same, respectively. The method for measuring the butanol content, chlorine content and bromine content of the metal-clad laminate is the same as the method for measuring the butanol content, the chlorine content and the bromine content described in the examples. is there.

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 in which a laminate with a metal foil is heat-press molded to be laminated and integrated; a metal foil is arranged on one side or both sides of one prepreg to obtain a prepreg with the metal foil, and the prepreg with the metal foil is used. Examples thereof include a method of heat-pressing molding and laminating and integrating. Examples of the method for heat-press molding include a multi-stage vacuum pressing method and a double belt pressing method. The conditions of the multi-stage vacuum press method are, for example, 140 to 200 ° C., 0.5 to 5.0 MPa, and 40 to 240 minutes.

[Printed wiring board 10 according to this embodiment]
The printed wiring board 10 of the present embodiment (hereinafter, may be simply referred to as a printed wiring board 10) may be 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 conductor wiring provided on one side or both sides of the cured product. The printed wiring board 10 has a single-layer structure printed wiring board (hereinafter, may be referred to as a core substrate) composed of a second insulating layer and conductor wiring on one side or both sides of the second insulating layer; conductor wiring of the core substrate. 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 and configured on the surface on which the above is formed. Includes a multi-layer printed wiring board with conductor wiring formed on the outer layer. The number of layers of the printed wiring board having a multi-layer structure is not particularly limited.

Since the second insulating layer constituting the printed wiring board 10 includes the cured product of the epoxy resin composition described above, the butanol content, chlorine content and bromine content of the printed wiring board 10 are determined after the epoxy resin composition is cured. Butanol content, chlorine content after curing, and bromine content after curing are the same, respectively. The method for measuring the butanol content, chlorine content and bromine content of the printed wiring board 10 is the same as the method for measuring the butanol content, the chlorine content and the bromine content described in the examples. is there.

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 with, 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.

The printed wiring board 10 is suitably used for the COB type semiconductor device 1. As shown in FIG. 1, the semiconductor device 1 includes a printed wiring board 10, a semiconductor 20, a gold wire 30, a joint body 40, and a sealing resin body 50. The conductor wiring of the printed wiring board 10 has an aluminum pad portion 11. The semiconductor 20 has an element surface 20a, and an electrode pad portion (not shown) is provided on the element surface 20a. The semiconductor 20 is placed on the printed wiring board 10 via the joint 40 so that the element surface 20a is on the side opposite to the printed wiring board 10 side. The electrode pad portion of the semiconductor 20 and the aluminum pad portion 11 of the printed wiring board 10 are electrically connected by a gold wire 30. The semiconductor 20, the gold wire 30, and the aluminum pad portion 11 are sealed by the sealing resin body 50. Further, electronic components for soldering such as a chip resistor and a chip capacitor may be mounted on the printed wiring board 10 of the semiconductor device 1.

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

[Examples 1 to 6, Comparative Examples 1 to 6]
(Epoxy resin composition)
The following materials were prepared as raw materials for the epoxy resin composition. An epoxy resin composition was prepared by blending the organic component, the inorganic component and the solvent in the ratios shown in Tables 1 and 2 and stirring and mixing them to homogenize them. Regarding the description of the mass part of each product in Tables 1 and 2, those having "(solid content)" indicate the mass part of the solid content of the product, and there is no description of "(solid content)". The thing refers to the mass part of the product itself.

<Organic component>
(Epoxy resin)
-Product name "EPPN502H" (Trisphenol methane type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 170 g / eq)
-Product name "HP4710" (tetrafunctional naphthalene type epoxy resin, manufactured by DIC Corporation, epoxy equivalent 240 g / eq)
-Product name "5046B80" (brominated bisphenol A type epoxy resin, Mitsubishi Chemical Co., Ltd., solvent: MEK (methyl ethyl ketone), bromine content: 21%, solid content: 80% (MEK cut), epoxy equivalent: 470 g / eq)
-Product name "NC3000" (biphenyl aralkyl type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 230 g / eq)
(Hardener)
-Product name "TD-2090 60M" (Novolac type phenolic resin, manufactured by DIC Corporation, solid content: 60%, solvent: MEK, hydroxyl group equivalent: 105 g / eq)
-Product name "XZ92741" (phosphophenol resin, manufactured by Dow Chemical Japan Co., Ltd.)
-Product name "LA-7052" (ATN (aminotriazine novolac), manufactured by DIC Corporation, solvent: MEK, nitrogen content: 8%, solid content: 60%, hydroxyl group equivalent: 120 g / eq)
(Curing accelerator)
・ Product name "2E4MZ" (imidazole, manufactured by Shikoku Chemicals Corporation)
<Inorganic component>
-Product name "SC2500-SQ" (spherical silica particles, manufactured by Admatex Co., Ltd., average particle diameter: 0.5 μm)
-Product name "SC5500-SQ" (spherical silica particles, manufactured by Admatex Co., Ltd., average particle diameter: 1.5 μm)
-Product name "AC9000-SI" (aluminum particles, manufactured by Admatex Co., Ltd., average particle diameter: 10 μm).

<Solvent>
・ MEK
-Butanol The epoxy equivalent, bromine content, solid content, hydroxyl group equivalent, nitrogen content and average particle size are catalog values.

(Prepreg)
Using the obtained epoxy resin composition, two types of prepregs, a first prepreg and a second prepreg, were obtained by the following continuous production method. The first prepreg is used as a material for a metal-clad laminate described later. The second prepreg is used in a thermal shock test and a four-layer plate moldability evaluation test, which will be described later.

<First prepreg>
A running long glass cloth (# 2116 type, WEA116E, E glass manufactured by Nitto Boseki Co., Ltd.) was impregnated into the epoxy resin composition so that the thickness of the cured product of the prepreg was 0.1 mm. Next, the epoxy resin composition impregnated in the glass cloth was heated and dried by a non-contact type heating unit until it became a semi-cured state. As a result, the solvent in the epoxy resin composition was removed. The heating temperature was 110 to 160 ° C. and the drying time was about 1.5 to 5 minutes. Then, it was cut to a required length to obtain a first prepreg containing a glass cloth and a semi-cured product of an epoxy resin composition impregnated in the glass cloth. The resin content (resin amount) of the first prepreg was 55 parts by mass with respect to 100 parts by mass of the first prepreg.

<Second prepreg>
A glass cloth (# 1078 type manufactured by Nitto Boseki Co., Ltd., WEA1078, E glass) was used, and this glass cloth was contained with an epoxy resin composition so that the thickness of the second prepreg was 0.06 mm. A second prepreg having a thickness of 0.06 mm was obtained in the same manner as in the continuous production method of the first prepreg.

(Metal-clad laminate)
Using the obtained first prepreg, a 0.4 mm-thick double-sided metal-clad laminate (hereinafter referred to as the first metal-clad laminate) and a 0.8 mm-thick double-sided metal-clad laminate are used by the following methods. Two types of metal-clad laminates (hereinafter referred to as second metal-clad laminates) were obtained. The first metal-clad laminate is a measurement test of butanol content, chlorine content, bromine content, glass transition temperature (Tg) and coefficient of thermal expansion (CTE (α1)), which will be described later, and an evaluation test of 4-layer plate moldability. Used for. The second metal-clad laminate is used for a thermal shock test, a water absorption measurement test, and a wire bonding bonding reliability evaluation test, which will be described later.

<First metal-clad laminate>
First, four first prepregs were laminated to obtain a laminate, and a first 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. Next, the laminate with the copper foil was heat-press molded to obtain a first metal-clad laminate having a thickness of 0.4 mm. The conditions for heat and pressure molding were 210 ° C., 4 MPa, and 120 minutes.

<Second metal-clad laminate>
A second metal-clad laminate having a thickness of 0.8 mm was obtained in the same manner as in the manufacturing method of the first metal-clad laminate except that eight first prepregs were laminated.

[Measurement and evaluation of material properties]
The butanol content, chlorine content, bromine content, glass transition temperature (Tg), resistance change rate, water absorption rate and thermal expansion coefficient (CTE (α1)) were measured by the following methods. Furthermore, the formability of the 4-layer plate and the bonding reliability of wire bonding were evaluated. The results of measurement and evaluation of material properties are shown in Tables 1 and 2. In Tables 1 and 2, "<0.16 (nd)" means that it is below the measurement detection limit.

(Butanol content)
A sample of only the cured product with a thickness of 0.2 mm by peeling off the cured product of the prepreg located on the surface together with the first copper foil adhered to both sides of the 0.4 mm thick first metal-clad laminate. Got The butanol content of the obtained sample was measured by gas chromatography-mass spectrometer (“TurboMatrix650ATD / Clarus600 / Clarus600T manufactured by PerkinElmer, Inc., column: SPB-1, adsorption heating conditions: heating at 130 ° C. for 60 minutes, column temperature rise). Conditions: 35 ° C. for 5 minutes to (10 ° C./min) to 100 ° C. to (20 ° C./min) to 290 ° C. for 24 minutes ", carrier gas: helium (1 mL / min), injection volume: 14.3%) , Measurement mode: Scan (m / z = 24-400) SIR (m / z = 31, 41, 56)) was used for quantification.

(Chlorine content, bromine content)
A sample of only the cured product with a thickness of 0.2 mm by peeling off the cured product of the prepreg located on the surface together with the first copper foil adhered to both sides of the 0.4 mm thick first metal-clad laminate. Got The chlorine content of the obtained sample was quantified by the silver nitrate titration method in accordance with the flask burning method specified in JIS K 7229. The bromine content of the obtained sample was quantified by the silver nitrate titration method in accordance with the flask burning method specified in JIS K 7229.

(Glass transition temperature Tg)
The first copper foil adhered to both sides of the first metal-clad laminate having a thickness of 0.4 mm was removed by etching to obtain a cured product of the laminate. 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. The glass transition temperature Tg of this sample is measured using a dynamic viscoelasticity measuring device (“DMA / DMS6100” manufactured by Seiko Instruments Inc.) in accordance with the DMA method (Dynamin-mechanical analysis) specified in JIS C 6481. did.

(Thermal impact test)
FIG. 2A is a schematic cross-sectional view of a portion where the 4-layer staircase daisy chain pattern is formed on the evaluation substrate. FIG. 2B is a schematic cross-sectional view of a portion where the outer layer daisy chain pattern of the evaluation substrate is formed. In FIGS. 2A and 2B, 60 is an evaluation substrate, 60A is a first portion where a 4-layer staircase daisy chain pattern is formed, 60B is a second portion where an outer layer daisy chain pattern is formed, 70 is a core substrate, and 71 is a core substrate. The cured product of the laminate, 72A and 72B are the inner layer wiring, 73 is the cured product of the second prepreg, 74A and 74B are through holes, 75A and 75B are the outer layer wiring, and 76A and 76B are through hole plating.

It has a first portion 60A on which a 4-layer staircase daisy chain pattern is formed and a second portion 60B on which an outer layer daisy chain pattern is formed by the following method, and has a starting point of a 4-layer staircase daisy chain pattern and an outer layer daisy chain. An evaluation substrate 60 was obtained in which the end point of the pattern was connected by a lead wire. The current E in the four-layer staircase daisy chain pattern flows in a stepped path as shown in FIG. 2A. The current E in the outer layer daisy chain pattern flows in a rectangular path as shown in FIG. 2B.

First, a part of the first copper foil adhered to both sides of the second metal-clad laminate having a thickness of 0.8 mm is removed by etching to form the first inner layer wiring 72A and the second inner layer wiring 72B to form the core substrate. I got 70.

Next, a second prepreg having a thickness of 0.06 mm and a second copper foil (thickness: 12 μm) were laminated in this order on both sides of the core substrate 70, and heat and pressure molding was performed to obtain a multilayer laminated plate. The conditions for heat and pressure molding were 210 ° C., 3 MPa, and 90 minutes.

The multi-layer laminated board was drilled and desmeared. As a result, 480 first through holes 74A having a diameter of 0.30 mm were formed at a pitch of 2.0 mm in the first portion 60A. Further, in the second portion 60B, 500 holes were formed in the second through hole 74B having a diameter of 0.30 mm at a pitch of 2.0 mm.

Next, a part of the second copper foil adhered to both sides of the multilayer laminated plate was removed by etching to form the first outer layer wiring 75A and the second outer layer wiring 75B.

Next, the inner walls of the first through hole 74A and the second through hole 74B were plated to form a first through-hole plating 76A and a second through-hole plating 76B having a thickness of 20 to 30 mm. As a result, a four-layer staircase daisy chain pattern was formed in the first portion 60A, and an outer layer daisy chain pattern was formed in the second portion 60B.

Next, the start point of the 4-layer staircase daisy chain pattern and the end point of the outer layer daisy chain pattern were connected by solder with lead wires to obtain an evaluation substrate 60 having a 980-hole daisy chain pattern.

The initial electrical resistance value of the daisy chain pattern of the evaluation substrate 60 was measured by the two-terminal method. Next, the evaluation substrate was placed in a temperature cycle tester, held at -40 ° C for 15 minutes, heated from -40 ° C to 185 ° C in 1.5 minutes, held at 185 ° C for 15 minutes, and held at 185 ° C. The process of lowering the temperature from to −40 ° C. in 1.5 minutes was performed as one cycle for 2000 cycles. The electric resistance value after the thermal shock test was measured, and the resistance change rate was calculated from the following formula.

Resistance change rate (%) = 100 x (electrical resistance value after thermal shock test-initial electric resistance value) / initial electric resistance value

(Water absorption rate)
The first copper foil adhered to both sides of the second metal-clad laminate having a thickness of 0.8 mm was removed by etching to obtain a cured product of the laminate. A sample was prepared according to JIS C6481 using the cured product of the obtained laminate. The water absorption rate of this sample at a temperature lower than the glass transition temperature of the cured product of the epoxy resin composition was measured according to JIS C 6481.

(Coefficient of thermal expansion (CTE (α1)))
The first copper foil adhered to both sides of the first metal-clad laminate having a thickness of 0.4 mm was removed by etching to obtain a cured product of the laminate. The coefficient of thermal expansion in the vertical direction of the cured product of the obtained laminate at a temperature lower than the glass transition temperature of the cured product of the epoxy resin composition was measured. The measurement was based on the TMA method (Termo-mechanical analysis) specified in JIS C6481, and a thermal analyzer (“TMA / SS6000” manufactured by Seiko Instruments Inc.) was used. Here, the vertical direction refers to a direction parallel to the traveling direction of the glass cloth when the prepreg is manufactured by the continuous manufacturing method on the surface of the cured product of the laminate.

(4 layer plate moldability)
FIG. 3A is a schematic front view of the core substrate 80 used in the evaluation test of the four-layer plate moldability, showing the hollow portion 81A formed in a part of the lattice pattern 81. FIG. 3B is an enlarged front view of a portion P in FIG. 3A. In FIG. 3A, the thin metal wire 82 is omitted.

A part of the first copper foil adhered to both sides of the first metal-clad laminate having a thickness of 0.4 mm was removed by etching to obtain a core substrate 80 (size: 340 mm × 510 mm). The core substrate 80 has a grid pattern 81 formed on both sides thereof. As shown in FIG. 3A, the grid pattern 81 has a hollow portion 81A and a grid portion 81B. As shown in FIG. 3A, the hollow portion 81A is a square-shaped portion (side length: 15 mm) in which the thin metal wire 82 is not formed, and each hollow portion 81A is regularly formed at intervals of 100 mm. ing. As shown in FIG. 3B, the grid portion 81B is a portion where a square grid 83 (one side length: 3.0 mm) composed of fine metal wires 82 (line width: 1.5 mm) is continuously formed. is there.

Next, a second prepreg having a thickness of 0.06 mm and a copper foil (thickness: 12 μm) were laminated in this order on both surfaces of the core substrate 80, and heat-press molded to obtain a four-layer plate.

This heat and pressure molding was performed under the following conditions. The unit pressure applied to the 4-layer plate is 0.49 to 0.98 MPa (5 to 10 kg / cm ² ) (primary pressure) for 20 to 30 minutes from the start of heat and pressure molding, and then the temperature applied to the 4-layer plate. (Hereinafter, product temperature) was increased to 120 ° C. at a heating rate of 3 ° C./min to 2.94 MPa (30 kg / cm ² ) (secondary pressure). Then, the secondary pressure was maintained until the heat-press molding process was completed. The product temperature was heated at a heating rate of 3 ° C./min from the start of heat-press molding until the product temperature reached 160 ° C., and then the product temperature was maintained at 160 ° C. or higher for 50 minutes. The maximum product temperature at this time was 170 to 180 ° C. Then, the four-layer plate was cooled to room temperature at a cooling rate of 2 to 6 ° C./min. The atmosphere was maintained at 13.3 kPa (100 Torr) or less until the product temperature reached 130 to 140 ° C., and then opened to the atmosphere.

All of the second copper foil adhered to both sides of the 4-layer plate was removed by etching, and the presence or absence of blurring was visually confirmed on both sides, and the 4-layer plate moldability was evaluated according to the following criteria.
◯: No blurring could be confirmed on both sides.
Δ: Cassoulet was confirmed only in the hollow portion 81A.
X: Blurring was confirmed in both the grid portion 81B and the hollow portion 81A on both sides.

Here, cassoulet means that when heat and pressure molding is performed, the epoxy resin composition constituting the second prepreg is not sufficiently spread so as to completely fill the entire lattice pattern 81, and the cured product of the second prepreg is used. It means that air bubbles remain between the cured product of the second prepreg and the lattice pattern 81. The portion where such bubble residue is generated looks white.

(Joining reliability of wire bonding)
A part of the first copper foil adhered to one side of a 0.8 mm thick second metal-clad laminate was removed by etching to form a conductor wiring. Further, an aluminum thin film (composition: Al98.5% by mass, Si 1.0% by mass, Cu 0.5% by mass) was formed on the conductor wiring by a sputtering method to obtain a printed wiring board having an aluminum pad portion. ..

FH-900-25 (manufactured by Hitachi Kasei Kogyo) is pasted on the back surface of the semiconductor wafer, diced to 7.5 mm x 7.5 mm using a dicer (DFD-6361 manufactured by DISCO), and a flexible die bonder ((()) on the printed wiring board. Thermocompression bonding was performed at 150 ° C./0.04 MPa/1 sec with DB730SP manufactured by Renesas East Japan Semiconductor Co., Ltd.

Next, using a thermosonic bonding (thermosonic) wire bonder (“FB-988” manufactured by Kaijo) and a gold wire (“GSB” manufactured by Tanaka Denshi Kogyo, wire diameter: 20 μm), a semiconductor and a semiconductor were used. A semiconductor device was obtained by electrically connecting to the aluminum pad portion of the printed wiring board.

This semiconductor device was introduced into a dryer and left to stand in an environment of 160 ° C. for 2000 hours. Next, the semiconductor device was taken out from the inside of the dryer, and then the cross-sectional observation of the connection portion between the pad portion and the wire was observed at 1000 points. The bonding reliability of wire bonding was evaluated according to the following criteria.
OK: No cracks of 4 μm or larger were observed.
NG: Cracks of 4 μm or more were observed.

1 Semiconductor device 10 Printed wiring board 11 Bond pad part 20 Semiconductor 30 Metal wire 40 Bonded body 50 Encapsulating resin body 60 Evaluation board 60A 4-layer staircase First part where daisy chain pattern is formed 60B Outer layer daisy chain pattern is formed Second part 70 Core substrate 71 Hardened laminate 72A, 72B Inner layer wiring 73 Hardened second prepreg 74A, 74B Through hole 75A, 75B Outer layer wiring 76A, 76B Through-hole plating

Claims (6)

It contains an organic component containing an epoxy resin having a naphthalene skeleton, a curing agent and a curing accelerator, and an inorganic component containing spherical silica particles having an average particle diameter of 1.5 μm or more and 3 μm or less.
The butanol content after curing is below the detection limit measured by gas chromatography-mass (GC-MS) analysis, the chlorine content after curing is 900 ppm or less, and the bromine content after curing is 900 ppm or less. An epoxy resin composition characterized by being present. The epoxy resin composition according to claim 1, wherein the curing agent has a phenol skeleton. The epoxy resin composition according to claim 1 or 2 , wherein the content of the inorganic component is 150 parts by mass or more and 220 parts by mass or less with respect to 100 parts by mass of the organic component. With fiber base material
A prepreg comprising the semi-cured product of the epoxy resin composition according to any one of claims 1 to 3 , which is impregnated with the fiber base material. A cured product of one prepreg or a cured product of a plurality of laminates according to claim 4 .
With the metal foil adhered to one or both sides of the cured product,
A metal-clad laminate characterized by being provided with. A cured product of one prepreg or a cured product of a plurality of laminates according to claim 4 .
With conductor wiring adhered to one or both sides of the cured product,
A printed wiring board characterized by being provided with.

Images