JP7247550B2 - ENCAPSULATING EPOXY RESIN COMPOSITION AND ELECTRONIC DEVICE - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition for encapsulation and an electronic device.

Various techniques have been developed for epoxy resin compositions for encapsulation. For example, Patent Literature 1 discloses a method for producing a granular semiconductor encapsulating resin composition suitable for compression molding and a semiconductor device encapsulated therewith. Compression molding is a method of manufacturing resin-encapsulated semiconductor devices by placing a semiconductor device in a mold, supplying molding resin between the mold and the semiconductor device, and performing compression molding. is.

JP 2015-116768 A

However, according to the studies of the inventors, when the sealing resin composition described in Patent Document 1 is used, there occurs a portion that cannot be completely covered with the sealing resin composition in the desired region to be sealed. there was a case. This is due to uneven spreading (uneven spreading) when the sealing resin composition for molding is supplied between the mold and the semiconductor device. It was noticeable when thinned.

According to the invention,
An epoxy resin composition comprising an epoxy resin, a curing agent, and a thermally expandable filler having a core-shell structure,
An encapsulating epoxy resin composition is provided, wherein the thermally expandable filler comprises a volatile expansion agent inside the shell in the core-shell structure.

Further, according to the present invention, there is provided an electronic device comprising a cured film of the epoxy resin composition for sealing.

According to the present invention, it is possible to reduce the occurrence of areas that cannot be completely covered with the sealing epoxy resin composition in the desired region to be sealed, and to reduce the uneven distribution of the sealing epoxy resin composition. An electronic device comprising a sealing epoxy resin composition and a cured film of the sealing epoxy resin composition is provided.

It is a sectional view showing an example of an electronic device concerning this embodiment. It is a sectional view showing an example of a manufacturing method of an electronic device concerning this embodiment.

Hereinafter, embodiments of the present invention will be described in detail.
In this specification, the notation "a to b" in the description of numerical ranges means from a to b, unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass or more and 5% by mass or less".
The notation "(meth)acryl" used herein represents a concept that includes both acryl and methacryl. The same applies to similar notations such as "(meth)acrylate".
The term "electronic device" as used herein refers to elements to which electronic engineering technology is applied, such as semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information communication terminals, light-emitting diodes, physical batteries, and chemical batteries. , devices, final products, etc.
In addition, in all the drawings, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Also, the drawings are schematic diagrams and do not correspond to actual dimensional ratios.

The encapsulating epoxy resin composition according to the present embodiment contains an epoxy resin, a curing agent, and a thermally expandable filler having a core-shell structure, and the thermally expandable filler volatility expands inside the shell in the core-shell structure. containing agents.
Here, the volatile expansion agent refers to a substance that generates gas at a temperature below the softening point of the shell. That is, the thermally expandable filler according to the present embodiment contains a volatile expanding agent therein and expands upon heating.
The epoxy resin composition for encapsulation according to the present embodiment has the above-described structure, thereby reducing the occurrence of areas that cannot be completely covered with the epoxy resin composition for encapsulation in the desired area to be sealed. It is possible to reduce uneven distribution of the epoxy resin composition for

Conventionally, transfer molding has been generally used as a method of encapsulating and molding semiconductor devices. However, when transfer molding is used, the bonding wires connected to the semiconductor chip are deformed by the flow pressure of the encapsulating resin. , there is a problem that disconnection or contact occurs. In order to solve this problem, a semiconductor device is placed in a mold, and an encapsulating epoxy resin composition (molding resin) is supplied between the mold and the semiconductor device for compression molding. Therefore, a method of manufacturing a resin-encapsulated semiconductor device has become mainstream.

In compression molding, a step of supplying a sealing epoxy resin composition onto a region to be sealed is essential. It is difficult to spread the composition evenly, especially when trying to form a thin cured film. (or voids) may occur. Therefore, especially when it is desired to seal an object to be sealed with a thin cured film, once the sealing is performed with a cured film thicker than the required specifications, the cured film is removed by polishing. We had no choice but to take a method of shaving and thinning. Therefore, from the viewpoint of process reduction, cost and work reduction, a thin cured film, specifically 100 μm or less, more preferably 50 μm or less, can be formed without a polishing process. There has been a demand for an epoxy resin composition for

Since the epoxy resin composition for encapsulation according to the present embodiment contains a thermally expandable filler, in the heating process subsequent to the step of supplying the epoxy resin composition for encapsulation to the region to be sealed, heat is applied. The expansion of the expandable filler causes the epoxy resin composition for sealing to expand (move), and the epoxy resin composition for sealing spreads evenly over the region to be sealed, and is not covered with the epoxy resin composition for sealing. It is believed that portions (or voids) can be reduced.
Note that the volatile expansion agent present inside the shell (core) of the thermally expandable filler escapes from the system during compression in the Z-axis direction during compression molding. It is considered that they do not remain in the cured product.
That is, in the first half of the compression molding process, the epoxy resin composition for sealing according to the present embodiment moves in the horizontal direction (XY axis direction) due to the expansion of the thermally expandable filler, spreads over the region to be sealed, and is compressed. In the latter half of the molding process, the volatile expansion agent present inside the shell of the thermally expandable filler and gas derived from air are crushed, so even if the desired cured film thickness is thin, the effect of uneven distribution can be reduced, and a cured product with few voids can be obtained.

The epoxy resin composition for sealing according to the present embodiment preferably has a volume expansion coefficient of 100%, more preferably 110% or more, measured under the following conditions. % or more, and particularly preferably 120% or more.
(conditions)
0.20 g of the epoxy resin composition for sealing is taken out, placed in an aluminum cup with an inner diameter of 53 mm, and photographed from right above the aluminum cup. The obtained image is binarized, and the ratio of the area G _A (mm ² ) of the portion covered with the sealing epoxy resin composition to the area D (mm ² ) of a circle with an inner diameter of 53 mm is shown. , to calculate the area ratio R _A =G _A /D. Subsequently, the aluminum cup containing the epoxy resin composition is heated at 175° C. for 3 minutes, and a photograph is taken again from directly above the aluminum cup. The resulting image was binarized, and the area ratio of the area G _B (mm ² ) of the portion covered with the sealing epoxy resin composition to the area D (mm ² ) of a circle with an inner diameter of 53 mm. The area ratio _RB = _GB /D is calculated. A coverage C is calculated from the ratio of the area ratio R _A and the area ratio R _B .
Formula (1) coverage C=R _B /R _A
Subsequently, the volume expansion coefficient E of the epoxy resin composition was calculated according to formula (2).
Formula (2) Volume expansion rate E (%) = C ^(3/2) × 100

In a conventional encapsulating epoxy resin composition that does not contain a thermally expandable filler, the effect of curing shrinkage is greater than that of expansion, so the volume expansion rate measured under the above conditions is less than 100%. Since the encapsulating epoxy resin composition according to the embodiment contains a thermally expandable filler, the formulation of the encapsulating epoxy resin composition is adjusted to reduce the effect of expansion due to the thermally expandable filler rather than the effect of curing shrinkage. The coefficient of volume expansion measured under the above conditions can be 100% or more by adjusting the ratio so that the ratio is larger. Although the upper limit of the volume expansion rate is not particularly limited, it can be, for example, 200% or less.

The volume expansion coefficient of the encapsulating epoxy resin composition can be adjusted by adjusting the maximum expansion starting temperature of the thermally expandable filler to be used, specifically the type and composition of the volatile expansion agent in the thermally expandable filler to be used. can be controlled by
Since the epoxy resin composition for sealing according to the present embodiment has a coefficient of volume expansion within the above numerical range, uneven distribution of the epoxy resin composition for sealing can be reduced, and a particularly thin cured film can be formed. When desired, a cured film of the sealing epoxy resin composition can be formed without pores or voids.

The expansion starting temperature of the sealing epoxy resin composition according to the present embodiment is preferably 50°C to 175°C, more preferably 70°C to 150°C, and 90°C to 140°C. is particularly preferred.

The maximum expansion temperature of the sealing epoxy resin composition according to the present embodiment is preferably 80°C to 180°C, more preferably 100°C to 190°C, and more preferably 120°C to 160°C. It is particularly preferred to have

The expansion start temperature and maximum expansion temperature of the epoxy resin composition for encapsulation can be obtained by the same method as the method for measuring the expansion start temperature and maximum expansion temperature of the thermally expandable filler according to the present embodiment, which will be described later. .
In addition, the expansion start temperature and maximum expansion temperature of the epoxy resin composition for sealing are the expansion start temperature of the thermally expandable filler used, specifically, the type and composition of the volatile expansion agent in the thermally expandable filler used. can be controlled by adjusting the
The epoxy resin composition for encapsulation according to the present embodiment can move more reliably in the horizontal direction (XY axis direction) in the compression molding process by setting the expansion start temperature and the maximum expansion temperature within the above numerical ranges. , the effect of uneven distribution can be further reduced because it spreads evenly over the region to be sealed.

The epoxy resin composition for sealing according to this embodiment can be in either liquid or solid form, but is preferably in solid form. In addition, the epoxy resin composition for sealing according to the present embodiment can be in the form of a tablet, a sheet, or a granule. It is preferably a granular sealing epoxy resin composition.

When the epoxy resin composition for sealing according to the present embodiment is in the form of granules, the average particle size is preferably 1 mm or less, more preferably 0.7 mm or less, and even more preferably 0.6 mm or less. is. As a result, it is possible to improve the fillability in a mold having a large area. The lower limit of the average particle size is not particularly limited, but is, for example, 0.1 mm or more, may exceed 0.3 mm, or may be 0.4 mm or more. This makes it possible to realize a granular epoxy resin composition for sealing that is excellent in production stability.
From the viewpoint of obtaining stable feedability to the compression molding die, productivity, and good weighing accuracy, the granules preferably contain less fine powder and coarse powder. The proportion of particles of 2 mm or more can be 3% by mass or less, and the proportion of fine powders of less than 106 μm can be 5% by mass or less.
The particle size distribution of granules can be determined by a sieving test using a JIS standard sieve.
Further, it is preferable that the granule density is, for example, 1.5 to 2.1 g/cm ³ .

The sealing epoxy resin composition according to the present embodiment preferably has fluidity (spiral flow) and curability (gel time/torque) suitable for molding. Spiral flow is 50 cm or more when the flow length is measured in a mold for spiral flow measurement according to EMMI-1-66 under the conditions of a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, and a pressure holding time of 120 seconds. The flat flow is preferably 10 cm or more when the flow length is measured under the conditions of a mold temperature of 175° C., an injection pressure of 6.9 MPa, and a pressure holding time of 120 seconds.
After the sample is placed on a hot plate at 175° C. and melted, it is preferably kneaded with a spatula until it hardens for 30 to 300 seconds.
The epoxy resin composition for sealing according to the present embodiment preferably has a shrinkage rate of less than 1% during resin sealing (ASM: as Mold), and a shrinkage rate during main curing of less than 1%. is preferably

Each component of the epoxy resin composition for sealing will be described below.

<Thermal expandable filler>
The encapsulating resin composition according to this embodiment contains a thermally expandable filler. The thermally expandable filler according to the present embodiment has a core-shell structure and contains a volatile expanding agent inside the shell of the core-shell structure.
Here, as described above, the volatile expansion agent refers to a substance that generates gas at a temperature below the softening point of the shell, and the thermally expandable filler according to the present embodiment is the inside of the shell having gas barrier properties. Since it has a structure in which a volatile expanding agent is included as a core agent, the volatile expanding agent becomes gaseous by heat, and the shell softens and expands.

The thermally expandable filler preferably has an average particle diameter (D ₅₀ ) of 1 μm or more and 200 μm or less, more preferably 3 μm or more and 100 μm or less, and 5 μm or more and 50 μm or less, as measured by a laser diffraction particle size distribution analyzer. is particularly preferred.
When the volume average particle diameter of the thermally expandable filler is within the above numerical range, the sealing epoxy resin composition spreads evenly over the region to be sealed during compression molding, and also spreads in the cured product. It is presumed that the epoxy resin composition for encapsulation has a good balance of the two, with few remaining voids.

The thermally expandable filler according to the present embodiment preferably has an expansion start temperature of 50°C to 175°C, more preferably 70°C to 150°C, and particularly preferably 90°C to 140°C. .

The maximum expansion temperature of the thermally expandable filler according to the present embodiment is preferably 80°C to 180°C, more preferably 100°C to 190°C, and more preferably 120°C to 160°C. Especially preferred.

The expansion start temperature and the maximum expansion temperature can be measured as follows using, for example, DMA. 0.5 mg of the thermally expandable filler is placed in an aluminum cup with a diameter of 6.0 mm and a depth of 4.8 mm, an aluminum lid is placed on top of the thermally expandable filler, and a force of 0.01 N is applied to the sample from above with a presser. Measure the height of the sample in the loaded state. In this state, the sample is heated from 20° C. to 300° C. at a rate of temperature increase of 10° C./min, and the amount of displacement of the presser in the vertical direction is measured. The positive displacement start temperature can be defined as the expansion start temperature (°C), and the temperature indicating the maximum amount of displacement can be defined as the maximum expansion temperature (°C).
By setting the expansion start temperature and maximum expansion temperature of the thermally expandable filler within the above numerical ranges, the encapsulating epoxy resin composition according to the present embodiment can be more reliably horizontally (XY axial direction) and spreads uniformly over the area to be sealed, the influence of uneven distribution can be reduced.

The maximum expansion ratio of the thermally expandable filler is preferably 3 times or more, more preferably 10 times or more, still more preferably 20 times or more, particularly preferably 30 times or more, and most preferably 50 times or more.
Note that the maximum expansion ratio means that when the volume of the particle group is measured by heating and expanding the particle group of the thermally expandable filler in an unexpanded state, the volume of the particle group is the maximum compared to that before thermal expansion. shows how many times the
By setting the maximum expansion ratio of the thermally expandable filler to the above aspect, the volume expansion coefficient of the encapsulating epoxy resin composition can be sufficiently increased, and uneven distribution of the encapsulating epoxy resin composition can be reduced. be able to.

In the thermally expandable filler according to the present embodiment, the volatile expanding agent includes, for example, ethane, ethylene, propane, propene, butane, isobutane, butene, isobutene, pentane, isopentane, neopentane, hexane, heptane, octane, nonane, Linear hydrocarbons such as decane, dodecane, undecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane; 4-methyldodecane, isotetradecane, isopentadecane, isohexadecane, 2,2,4,4,6,8,8-heptamethylnonane, isoheptadecane, isooctadecane, isononadecane, 2,6,10,14-tetramethylpentadecane branched hydrocarbons such as; Alicyclic hydrocarbons such as decylcyclohexane, hexadecylcyclohexane, heptadecylcyclohexane, octadecylcyclohexane; petroleum ethers; halides thereof; chlorofluorocarbons such as _CCl3F , _{CCl2F2 , CClF3} , CClF2 _{- CClF2} ; fluorine-containing compounds such as hydrofluoroethers; tetraalkylsilanes such as tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane and trimethyl-n-propylsilane; and compounds that are thermally decomposed to generate gas by heating. These volatile swelling agents may be used alone, or two or more of them may be used in combination. Also, the volatile swelling agent preferably contains a hydrocarbon.

Among these, the volatile swelling agent preferably contains at least one selected from propane, butane, pentane, hexane, heptane, isobutane, isopentane, isohexane, isoheptane, isooctane, cyclopentane, cyclohexane, and petroleum ether. is particularly preferred.

The volatile expanding agent preferably contains a hydrocarbon with a boiling point of -30°C or higher and 175°C or lower, more preferably a hydrocarbon with a boiling point of -20°C or higher and 150°C or lower. When the boiling point of the volatile expanding agent is within the above numerical range, the thermally expandable filler expands sufficiently so that the encapsulating epoxy resin composition can sufficiently move.

Moreover, in the thermally expandable filler, the shell in the core-shell structure preferably contains a thermoplastic resin. When the shell contains a thermoplastic resin, the volatile expansion agent present in the core inside the shell expands as the volatile expansion agent present in the core inside the shell expands in volume when heated, and expands with the gas trapped inside, and is used for sealing during molding. It is considered to contribute to horizontal movement of the epoxy resin composition.

The thermoplastic resin includes a structural unit derived from vinylidene chloride, a structural unit derived from a nitrile-based monomer, a structural unit derived from a (meth)acrylic acid ester-based monomer, a structural unit derived from a monomer having an amide group, and It is preferably a polymer having at least one structural unit selected from the group consisting of a structural unit derived from a monomer having a glycidyl group in the molecule.
When the thermoplastic resin contains the above-described polymer, the shell of the thermally expandable filler has sufficiently high gas barrier properties and optimum flexibility and elasticity.

From the viewpoint of selecting the thermoplastic resin having low reactivity with the epoxy resin contained in the epoxy resin composition for sealing of the present embodiment, the structural unit derived from a (meth)acrylic acid ester-based monomer is selected as the thermoplastic resin. It is particularly preferred to include

In the present embodiment, the content of the thermally expandable filler in the encapsulating resin composition is, for example, 0.1% by mass or more and 20% by mass with respect to 100% by mass of the total solid content of the encapsulating resin composition. %, more preferably 0.2% by mass or more and 10% by mass or less, and particularly preferably 0.5% by mass or more and 5% by mass or less.
By setting the content of the thermally expandable filler within the above numerical range, the volume expansion coefficient, expansion start temperature, and maximum expansion temperature of the resulting sealing epoxy resin composition can be controlled to appropriate values. It is possible to reduce the unevenness of spraying.

<Epoxy resin>
The encapsulating epoxy resin composition of the present invention contains an epoxy resin. Specific examples of the epoxy resin include, for example, biphenyl type epoxy resin; bisphenol type epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethylbisphenol F type epoxy resin; stilbene type epoxy resin; phenol novolac type epoxy resin. novolac type epoxy resins such as resins, cresol novolac type epoxy resins; phenol aralkyl epoxy resins such as phenol aralkyl epoxy resins having a phenylene skeleton, naphthol aralkyl epoxy resins having a phenylene skeleton, phenol aralkyl epoxy resins having a biphenylene skeleton, and naphthol aralkyl epoxy resins having a biphenylene skeleton; dihydroxynaphthalene epoxy resins, naphthol-type epoxy resins such as epoxy resins obtained by glycidyl-etherifying dimers of dihydroxynaphthalene; triazine nucleus-containing epoxy resins such as triglycidyl isocyanurate and monoallyl diglycidyl isocyanurate; dicyclopentadiene-modified phenol-type epoxy resins, etc. and a bridged cyclic hydrocarbon compound-modified phenolic epoxy resin. As the epoxy resin, one of these may be used alone, or two or more different types may be used in combination.

In the present embodiment, the lower limit of the content of the epoxy resin in the encapsulating resin composition is, for example, 1% by mass or more with respect to 100% by mass of the total solid content of the encapsulating resin composition. Preferably, it is 2% by mass or more.
In addition, the upper limit of the content of the epoxy resin in the resin composition for encapsulation is preferably, for example, 15% by mass or less with respect to 100% by mass of the total solid content of the resin composition for encapsulation. It is more preferably 5% by mass or less, more preferably 5% by mass or less. Thereby, the fluidity of the encapsulating resin composition during molding can be appropriately set. Therefore, filling properties can be improved. In addition, in this embodiment, the total solid content of the encapsulating resin composition indicates the sum of all components excluding the solvent.

<Curing agent>
Examples of the curing agent include linear aliphatic diamines having 2 to 20 carbon atoms such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, metaphenylenediamine, paraphenylenediamine, paraxylenediamine, 4,4 '-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodicyclohexane, bis(4-aminophenyl)phenylmethane, Aminos such as 1,5-diaminonaphthalene, metaxylenediamine, paraxylenediamine, 1,1-bis(4-aminophenyl)cyclohexane, and dicyanodiamide; resol-type phenolic resins such as aniline-modified resole resins and dimethyl ether resole resins; Phenol novolak resin, cresol novolak resin, tert-butylphenol novolak resin, novolac type phenol resin such as nonylphenol novolak resin; polyfunctional phenol resin such as trihydroxyphenylmethane type phenol resin; phenylene skeleton-containing phenol aralkyl resin, biphenylene skeleton-containing phenol Phenolic aralkyl resins such as aralkyl resins; Phenolic resins having condensed polycyclic structures such as naphthalene skeletons and anthracene skeletons; Polyoxystyrenes such as polyparaoxystyrene; Hexahydrophthalic anhydride (HHPA), Methyltetrahydrophthalic anhydride (MTHPA) Acid anhydrides including alicyclic acid anhydrides such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), aromatic acid anhydrides such as benzophenonetetracarboxylic acid (BTDA), etc.; polysulfide, thioester , thioether, and other polymercaptan compounds; isocyanate compounds, such as isocyanate prepolymers and blocked isocyanates; and organic acids, such as carboxylic acid-containing polyester resins. These may be used individually by 1 type, or may be used in combination of 2 or more types.

Among these, the curing agent is preferably a compound having at least two phenolic hydroxyl groups in one molecule from the viewpoint of moisture resistance, reliability, etc. Novolac-type phenolic resins such as novolak resins and silicon-modified phenolic novolac resins; resol-type phenolic resins; polyoxystyrenes such as polyparaoxystyrene; etc. are exemplified. Among these, trihydroxyphenylmethane-type phenolic resins can be used from the viewpoint of heat resistance of the cured epoxy resin composition for encapsulation and workability during mold molding.

In the present embodiment, the upper limit of the content of the curing agent in the sealing epoxy resin composition is preferably, for example, 10.0% by mass or less with respect to the total solid content of the sealing resin composition. , 7.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less. Thereby, the fluidity at the time of molding can be improved. Therefore, filling properties can be improved.
In addition, the lower limit of the content of the curing agent in the encapsulating resin composition is, for example, preferably 0.3% by mass or more with respect to the total solid content of the encapsulating resin composition, and 0.5% by mass or more. It is more preferably 1.0% by mass or more, more preferably 1.0% by mass or more. Thereby, the curing speed of the encapsulating resin composition can be appropriately adjusted. Therefore, it is possible to suppress the internal stress from increasing due to the progress of the local curing reaction.

<Inorganic filler>
An inorganic filler can be used in the sealing epoxy resin composition according to the present embodiment. Examples of inorganic fillers to be used include silica such as fused crushed silica, fused spherical silica, crystalline silica, and secondary agglomerated silica; alumina; titanium white; aluminum hydroxide; talc; ; glass fiber and the like. Among these, fused spherical silica is particularly preferred. In addition, it is preferable that the particle shape of silica is infinitely spherical. These may be used alone or in combination of two or more.

The upper limit of the average particle size _d50 of the inorganic filler is, for example, 5 μm or less, preferably 4.5 μm or less, and more preferably 4 μm or less, from the viewpoint of mold filling properties. As a result, it is possible to improve the filling property in a mold having a large area. Moreover, the lower limit of the average particle diameter _d50 of the inorganic filler is not particularly limited, but can be, for example, 0.01 μm or more.
In the present embodiment, the average particle size d ₅₀ of the inorganic filler can be measured using, for example, a laser diffraction particle size distribution analyzer (LA-500, manufactured by HORIBA).

In the present embodiment, the lower limit of the content of the inorganic filler is, for example, 70% by mass or more, preferably 75% by mass or more, more preferably 80% by mass, based on the entire epoxy resin composition for sealing. % by mass or more. As a result, the low hygroscopicity and low thermal expansion of the cured product of the sealing epoxy resin composition can be improved, and the moisture resistance reliability and reflow resistance of the electronic device can be improved more effectively. In addition, the upper limit of the content of the inorganic filler is not particularly limited, but for example, it is preferably 95% by mass or less, and 93% by mass or less with respect to the entire sealing epoxy resin composition. is more preferable, and 90% by mass or less is particularly preferable. This makes it possible to more effectively improve the fluidity and fillability of the encapsulating epoxy resin composition during molding.

<Curing accelerator>
A curing accelerator can be used in the sealing epoxy resin composition according to the present embodiment. As the curing accelerator to be used, any one that accelerates the curing reaction between the epoxy group and the curing agent can be used, and those that are generally used for sealing materials can be used. Examples of the curing accelerator include phosphorus atom-containing compounds such as organic phosphines, tetrasubstituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, adducts of phosphonium compounds and silane compounds; - diazabicyclo[5.4.0]undecene-7, benzyldimethylamine, 2-methylimidazole, etc. are selected from nitrogen atom-containing compounds such as amidines, tertiary amines, and quaternary salts of the above amidines and amines; One type or two or more types can be included. Among these, it is more preferable to contain a phosphorus atom-containing compound from the viewpoint of improving curability. In addition, from the viewpoint of improving the balance between moldability and curability, tetrasubstituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, adducts of phosphonium compounds and silane compounds, etc. have latent properties. It is more preferable to include These may be used individually by 1 type, or may be used in combination of 2 or more types.
Examples of organic phosphines include primary phosphines such as ethylphosphine and phenylphosphine; secondary phosphines such as dimethylphosphine and diphenylphosphine; and tertiary phosphines such as trimethylphosphine, triethylphosphine, tributylphosphine and triphenylphosphine. mentioned.
A more preferable one is a latent curing accelerator that causes less rapid increase in viscosity after the epoxy resin composition for sealing is melted.

<Silicone oil>
The sealing epoxy resin composition of the present embodiment can contain silicone oil.

（ただし、上記一般式（１）において、Ｒ１は炭素数１ないし１２のアルキル基、アリール基、アラルキル基から選択される有機基であり、互いに同一であっても異なっていてもよい。Ｒ^２は炭素数１ないし９のアルキレン基を示す。Ｒ^３は水素原子又は炭素数１ないし９のアルキル基である。Ａは、炭素、窒素、酸素、硫黄、水素から選択される原子から構成される基である。Ｒ４は炭素数１ないし１２のアルキル基、アリール基、アラルキル基から選択される有機基、又は炭素、窒素、酸素、硫黄、水素から選択される原子から構成される基であり、互いに同一であっても異なっていてもよい。また、平均値であるｌ、ｍ、ｎ、ａ、及びｂについては以下の関係にある。
ｌ≧０、ｍ≧０、ｎ≧１、ｌ＋ｍ＋ｎ≧５、
０．０２≦ｎ／（ｌ＋ｍ＋ｎ）≦０．８、
ａ≧０、ｂ≧０、ａ＋ｂ≧１） As the silicone oil, for example, a compound having a polyether group in the molecule is used. As such a silicone oil, a silicone oil represented by the following general formula (1) can be used. These may be used alone or in combination of two or more.

(In general formula (1) above, R1 is an organic group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group, and an aralkyl group, and may be the same or different. ^R2 represents an alkylene group having 1 to 9 carbon atoms, R ³ is a hydrogen atom or an alkyl group having 1 to 9 carbon atoms, A is composed of atoms selected from carbon, nitrogen, oxygen, sulfur and hydrogen R4 is an organic group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group and an aralkyl group, or a group composed of atoms selected from carbon, nitrogen, oxygen, sulfur and hydrogen; The average values l, m, n, a, and b have the following relationship.
l≧0, m≧0, n≧1, l+m+n≧5,
0.02≦n/(l+m+n)≦0.8,
a≧0, b≧0, a+b≧1)

The repeating number (n) of the polyether group-containing unit in the silicone oil represented by the general formula (1) is 0.02 with respect to the degree of polymerization (l + m + n) of the silicone oil represented by the general formula (1). Above, it is preferable to be in the range of 0.8 or less. When the ratio of the repeating number (n) of the polyether group-containing unit is within the above range, the compatibility between the silicone oil and the resin component is in an appropriate state, exhibiting a surfactant action, and homogenizing the resin component. effect will be obtained. Further, when the ratio of the number of repetitions (n) of the polyether group-containing units is within the above range, it is possible to suppress an increase in the amount of moisture absorbed by the resin composition due to the presence of excess polyether groups, resulting in a decrease in solder heat resistance. can be suppressed.

The silicone oil of the present embodiment is not particularly limited in the average degree of polymerization, and in order to impart affinity with epoxy resins, phenolic resins, and inorganic fillers, in addition to methyl groups and phenyl groups, C, O, N, It may have an organic group containing an S atom or the like.

For example, the silicone oil represented by the general formula (1) has various groups composed of atoms selected from carbon, nitrogen, oxygen, sulfur, and hydrogen atoms in the molecule in addition to the polyether group. You may Examples of these groups include epoxy groups, hydroxyl groups, amino groups, ureido groups, functional groups having reactivity with epoxy resins and curing agents, and aryl groups.

In the present embodiment, the lower limit of the content of silicone oil is not particularly limited. or more, more preferably 0.1% by mass or more. Thereby, the silicone oil can bleed to the interface of the cured epoxy resin composition for sealing, and the wettability of the interface can be optimized. The upper limit of the silicone oil content is not particularly limited, but is, for example, 1% by mass or less, preferably 0.5% by mass or less, relative to the entire sealing epoxy resin composition. As a result, the bleeding amount of the silicone oil can be appropriately controlled, so that deterioration of the moldability of the cured product of the sealing epoxy resin composition can be suppressed.

In addition to the above components, the epoxy resin composition for sealing of the present embodiment may optionally include a coupling agent, a leveling agent, a colorant, a release agent, a low stress agent, a photosensitizer, an antifoaming agent, and an ultraviolet absorber. It may contain one or more additives selected from agents, foaming agents, antioxidants, flame retardants, ion scavengers, and the like.

Examples of the coupling agent include epoxysilane coupling agent, cationic silane coupling agent, aminosilane coupling agent, γ-glycidoxypropyltrimethoxysilane coupling agent, phenylaminopropyltrimethoxysilane coupling agent, mercapto Examples include silane coupling agents such as silane coupling agents, titanate coupling agents, and silicone oil coupling agents. Examples of the leveling agent include acrylic copolymers. Carbon black etc. are mentioned as said coloring agent. Examples of the release agent include natural waxes, synthetic waxes such as montan acid esters, higher fatty acids or metal salts thereof, paraffin, polyethylene oxide, and the like. Silicone rubber etc. are mentioned as said low stress agent. Hydrotalcite etc. are mentioned as an ion trapping agent. Aluminum hydroxide etc. are mentioned as a flame retardant. In this embodiment, for example, the silicone oil and the release agent may be used in combination.

<Method for Producing Sealing Epoxy Resin Composition>
A method for obtaining the sealing epoxy resin composition according to this embodiment will be described. The epoxy resin composition for encapsulation according to this embodiment is not particularly limited in its manufacturing method as long as it satisfies the configuration according to this embodiment, but can be manufactured, for example, by the following method.
Specifically, a melt-kneaded resin composition is supplied to the inside of a rotor composed of a cylindrical outer peripheral portion having a plurality of small holes and a disk-shaped bottom surface, and the resin composition is applied to the rotor. A method of passing through small holes by centrifugal force obtained by rotation (hereinafter also referred to as “centrifugal milling method”); After heating and kneading, the product is cooled and pulverized, and the pulverized product is obtained by removing coarse particles and fine powder using a sieve (hereinafter also referred to as “pulverization and sieving method”); each raw material component After premixing with a mixer, heat kneading is performed using an extruder equipped with multiple dies with small diameters at the tip of the screw, and the molten resin extruded in strands from small holes arranged in the die. A method of cutting with a cutter that slides and rotates substantially parallel to the die surface (hereinafter also referred to as a “hot cut method”), and the like.
In any method, in the manufacturing process, it is possible to keep the temperature lower than the expansion start temperature of the thermally expandable filler used as the raw material, or keep the time at which the thermally expandable filler used as the raw material rises to the expansion start temperature or higher for a short time. For example, the mixing temperature is preferably 110° C. or lower, particularly preferably 100° C. or lower.

The epoxy resin composition for encapsulation according to the present embodiment can be used for encapsulation of semiconductor elements, and is not limited to encapsulation of semiconductor elements. ), and sealing of rotor cores. When used for encapsulating semiconductor elements, examples of the semiconductor elements include integrated circuits, large-scale integrated circuits, transistors, thyristors, diodes, and solid-state imaging devices. Examples of the structure of a semiconductor package including a semiconductor element include a ball grid array (BGA), a MAP type BGA, and the like. Also, chip size package (CSP), quad flat non-leaded package (QFN), embedded WLP (eWLP), wafer level package (WLP) such as Fan In WLP and Fan Out WLP, small outline non A leaded package (SON), a lead frame BGA (LF-BGA), and the like are included.
The sealing epoxy resin composition according to this embodiment is particularly preferably used for wafer level packages (WLP).

<Electronic device according to the present embodiment>
An example of the electronic device of this embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the configuration of an electronic device 100 of this embodiment.

The electronic device 100 of this embodiment can be a semiconductor device that includes an electronic component (semiconductor chip 140). In this embodiment, the semiconductor chip 140 may comprise an insulating layer and a metal layer (not shown) and has copper pillars 20 . The semiconductor chip 140 is sealed with a cured epoxy resin composition for sealing (the sealing material layer 30). The upper surface of the copper pillar 20 and the upper surface of the encapsulant layer 30 may constitute the same plane, and the rewiring insulating layer 80 is formed on these upper surfaces. The rewiring insulating layer 80 has vias 92 penetrating the rewiring insulating layer 80 , and a rewiring circuit 94 is formed on the upper surface of the rewiring insulating layer 80 . Solder balls 96 are mounted on the rewiring circuit 94 , and a solder resist layer 98 is formed to cover the rewiring circuit 94 and the solder balls 96 . Copper pillars 20 are electrically connected to solder balls 96 through vias 92 and redistribution circuits 94 . The vias 92 and the redistribution circuit 94 may be made of metal such as copper, for example.

(Method for manufacturing electronic device)
A method for manufacturing an electronic device according to this embodiment will be described.
The method for manufacturing an electronic device according to the present embodiment includes, for example, an arrangement step of arranging an electronic component on a base material, and a sealing step of sealing the electronic component using the sealing resin composition described above. and including.

(Arrangement process)
In the arranging step, the electronic component is arranged on the base material.
The number of electronic components arranged in the arrangement step is not limited. For example, one electronic component may be arranged on the base material, or a plurality of electronic components may be arranged on the base material. good.
In the disposing step, for example, an electronic component such as an electronic circuit may be formed on a substrate such as a wafer, or an electronic component such as a semiconductor element may be arranged on a substrate such as an organic substrate.
Since the encapsulating resin composition according to the present embodiment has excellent filling properties, it can be suitably used, for example, when stacking a plurality of chips.

(sealing process)
In the encapsulation step, the electronic component is encapsulated using the encapsulating resin composition described above. Thereby, the sealing member mentioned above can be formed with the hardened|cured material of the resin composition for sealing.
Specific examples of sealing methods include transfer molding, compression molding, and injection molding. By these methods, a sealing member can be formed by molding and curing the sealing resin composition. The encapsulating resin composition of the present embodiment can be suitably used for encapsulating a large-area substrate.

A specific electronic device and its manufacturing method will be described below.
FIG. 2 shows an example of a method of manufacturing an electronic device of Wafer Level Package (:WLP).

As a method for manufacturing an electronic device of Wafer Level Package (:WLP), for example, a circuit surface is formed by arranging a plurality of electronic components on a substrate in the above-described arrangement step, and furthermore, the above-mentioned In the sealing step, sealing is performed using a sealing resin composition so as to cover the circuit surface, and after the sealing step, the sealing resin composition covering the circuit surface of the base material, and the base material is cut to separate the electronic device into individual pieces.
In addition, as an arrangement step, for example, bumps may be formed on the circuit surface. Further, as the sealing step, the sealing material layer may be scraped to expose the bumps from the sealing material layer. Furthermore, after the sealing process, solder balls may be connected to the bumps as a wiring process.

A method of manufacturing an electronic device of Wafer Level Package (:WLP) will be described in detail together with the steps shown in FIGS.
First, as an arrangement step, for example, as shown in FIG. 2A, a plurality of electronic components 21 are arranged on a substrate 10 such as a wafer. As shown in FIG. 2B, bumps 22 such as metal posts are formed on the electronic component 21 to electrically connect solder balls, which will be described later, to the electronic component.
Next, as a sealing step, a sealing resin composition is used to seal the electronic component 21 so as to cover it, thereby forming a sealing material layer 30 . Conventionally, as shown in FIG. 2C, the bumps 22 are exposed from the encapsulant layer 30 by forming a resin film higher than the bumps 22 and then scraping the encapsulant layer 30. By the way, according to the present invention, a configuration in which the bumps 22 are exposed can be obtained without going through the polishing process (FIG. 2(d)). Alternatively, according to the present invention, a configuration in which the bumps 22 are exposed can be obtained with a small amount of polishing.
Next, as a wiring process, for example, solder balls 96 are connected to the bumps 22 as shown in FIG.
Next, as a singulation step, for example, as shown in FIG. 2( f ), the encapsulant layer 30 and the base material 10 are cut with a dicing blade, laser, or the like to obtain the electronic device 50 . The number of bumps 22 and solder balls 96 connected to the electronic device 50 to be singulated is not limited, and can be set according to the type of the electronic device 50 .

Here, in this embodiment, an outline of compression molding using a granular thermosetting resin composition will be described.

First, a granular thermosetting resin composition is uniformly sown on the bottom surface of the lower mold cavity of the compression molding die. For example, using a conveying means such as a vibration feeder, the granular thermosetting resin composition may be conveyed and placed on the bottom surface of the lower mold cavity.
Subsequently, the base material 10 with the electronic component 21 formed thereon is fixed to the upper mold of the compression molding die by a fixing means such as a clamp or suction. Subsequently, by narrowing the gap between the upper mold and the lower mold under reduced pressure, the granular thermosetting resin composition is heated to a predetermined temperature in the lower mold cavity and melted. Subsequently, by joining the upper mold and the lower mold, the molten thermosetting resin composition is pressed against the electronic component 21 fixed to the upper mold. After that, the thermosetting resin composition is cured over a predetermined period of time while the upper mold and the lower mold of the mold are held together. Thereby, the sealing material layer 30 sealing the electronic component 21 and the bumps 22 on the substrate 10 can be formed.
In this embodiment, even when a sheet-like thermosetting resin composition is used in place of the granular thermosetting resin composition, the compression molding as described above can be used.

Here, when performing compression molding, it is preferable to perform sealing while reducing the pressure in the mold, more preferably under vacuum conditions. As a result, the electronic component 21, the bumps 22, and the like can be embedded with the cured product of the thermosetting resin composition (sealant layer 30) without leaving any filled portions.

The molding temperature in compression molding may be, for example, 100° C. or higher and 200° C. or lower, or 120° C. or higher and 180° C. or lower. The molding pressure may be, for example, 0.5 MPa or more and 12 MPa or less, or 1 MPa or more and 10 MPa or less. The molding time may be, for example, 30 seconds or more and 15 minutes or less, or 1 minute or more and 10 minutes or less. In the present embodiment, by setting the molding temperature, pressure, and time within the ranges described above, it is possible to prevent occurrence of portions not filled with the molten sealing material.

After sealing, the cured product (insulating layer 224) of the obtained thermosetting resin composition may be post-cured. The post cure temperature may be, for example, 150° C. or higher and 200° C. or lower, or 165° C. or higher and 185° C. or lower. The post cure time may be, for example, 1 hour or more and 5 hours or less, or 2 hours or more and 4 hours or less.

Although the embodiments of the present invention have been described above with reference to the drawings, these are examples of the present invention, and various configurations other than those described above can also be adopted.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to the description of these Examples.

Raw material components used in each example and each comparative example are shown below.

(Epoxy resin)
Epoxy resin 1: Biphenylene skeleton-containing phenol aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC3000L)

(curing agent)
Curing agent 1: Biphenylene skeleton-containing phenol aralkyl type phenolic resin (manufactured by Meiwa Kasei Co., Ltd., MEH-7851SS)

(Curing accelerator)
Curing accelerator 1: tetraphenylphosphonium 4,4'-sulfonyl diphenolate Curing accelerator 2: tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenyl silicate

(Inorganic filler)
Inorganic filler 1: spherical fused silica (manufactured by Micron, average particle size 2 μm)

(Thermal expandable filler)
Thermally expandable filler 1: Matsumoto Yushi Seiyaku Co., Ltd., FN-100SSD, average particle size 10-20 μm, expansion start temperature 120-130° C., maximum expansion temperature 145-155° C. Thermally expandable filler 1 and EVA binder are combined into a solid Expansion coefficient when heated (160 ° C.) in a composition mixed at a weight ratio of 9: 1: 5.4 times Thermally expandable filler 2: Matsumoto Yushi Seiyaku Co., Ltd., FN-80GSD, average particle size 10 to 20 μm, expansion starts Temperature 100 to 110°C, maximum expansion temperature 125 to 135°C, thermally expandable filler 2 and EVA binder mixed at a solid content weight ratio of 9:1, expansion rate when heated (150°C) 7.6 times

(coloring agent)
Colorant 1: Carbon black (Tokai Carbon, ERS-2001)

(coupling agent)
Coupling agent 1: N-phenylaminopropyltrimethoxysilane represented by the following formula (S1) (CF-4083 manufactured by Dow Corning Toray Co., Ltd.)

Coupling agent 2: A hydrolyzate of a silane coupling agent represented by the following formula (in the following formula, a structure in which the terminal _OCH3 structure is changed to OH)

(Release agent)
Release agent 1: diethanolamine dimontan acid ester (NC-133, manufactured by Ito Oil Co., Ltd.)

(Ion scavenger)
Ion scavenger 1: Hydroxytalcite (Toagosei)

(silicone oil)
Silicone oil 1: Organofunctional siloxane (FZ-3730, Toray Dow)

(Low stress agent)
Low stress agent 1: Carboxyl group-terminated butadiene-acrylonitrile copolymer (CTBN1008SP, PTI JAPAN)

<Preparation of Sealing Epoxy Resin Compositions of Examples 1 and 2 and Comparative Example 1>
For each of Examples and Comparative Examples, a sealing resin composition was prepared as follows.
First, each component shown in Table 1 was mixed with a mixer. Next, the resulting mixture was melt-kneaded at a resin temperature of 100° C. at a screw speed of 30 rpm and a co-rotating twin-screw extruder having a cylinder inner diameter of 65 mm in diameter. Next, the melted and kneaded resin composition was supplied from above a rotor having a diameter of 20 cm at a rate of 2 kg/hr. It was allowed to pass through a plurality of small holes (hole diameter 1.2 mm) in the outer peripheral portion. Then, by cooling, a granular epoxy resin composition for sealing was obtained.
The details of each component in Table 1 are as described above. In addition, all the compounding ratios of each component shown in Table 1 refer to parts by mass.

<Evaluation>
(Volume expansion rate)
0.20 g of the encapsulating epoxy resin composition of each example and comparative example was taken, put into a cylindrical aluminum cup with an inner diameter of 53 mm so as to be evenly distributed, and a photograph was taken from directly above the aluminum cup. The photographed image is binarized into the portion where the aluminum is exposed and the portion covered with the epoxy resin composition for sealing, and the area GA of the portion covered with the epoxy resin composition for sealing is obtained _. (mm ² ) was calculated. Subsequently, by dividing the area G _A (mm ² ) of the portion covered with the sealing epoxy resin composition by the area of the bottom surface of the aluminum cup (area D (mm ² ) of a circle with a diameter of 53 mm), , an area ratio _RA (= _GA /D), which indicates the ratio of the area of the portion covered with the encapsulating epoxy resin composition, was calculated. Subsequently, the aluminum cup containing the epoxy resin composition was heated at 175° C. for 3 minutes, and the aluminum cup containing the epoxy resin composition after heating was again photographed from right above the aluminum cup. In the same manner as before heating, the photographed image is binarized into the portion where the aluminum is exposed and the portion covered with the epoxy resin composition for sealing, and the portion covered with the epoxy resin composition for sealing is processed. The area _GB (mm ² ) of the portion where the Subsequently, by dividing the area _GB (mm ² ) of the portion covered with the sealing epoxy resin composition by the area of the bottom surface of the aluminum cup (area D (mm ² ) of a circle with a diameter of 53 mm), , an area ratio _RB (= _GB /D), which indicates the ratio of the area of the portion covered with the encapsulating epoxy resin composition, was calculated. The ratio of these area ratios was used to calculate the coverage C by the following formula (1).
Formula (1) coverage C=R _B /R _A
Subsequently, the volume expansion coefficient E of the epoxy resin composition was calculated according to formula (2).
Formula (2) Volume expansion rate E (%) = C ^(3/2) × 100

(flat flow)
Using a low-pressure transfer molding machine (KTS-15, manufactured by Kotaki Seiki Co., Ltd.), a mold for flow characteristics evaluation (flat flow mold) was placed at a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, and a pressure holding time of 120 seconds. The resin composition for semiconductor encapsulation was injected under the conditions of , and the flow distance from the start point to the end point of the flow of the resin composition for semiconductor encapsulation was determined as the flow length. The unit is cm.

(gel time)
A sample composed of the epoxy resin composition for sealing of each example and comparative example was placed on a hot plate heated to 175° C., and the time until the sample was cured was measured while being kneaded with a spatula after the sample was melted. A shorter time indicates a faster curing speed.

(Measurement of viscosity η)
The encapsulating epoxy resin compositions of Examples and Comparative Examples were tested using a Koka flow tester (CFT-500C, manufactured by Shimadzu Corporation) at a temperature of 175°C under a load of 40 kgf (piston area: 1 cm ² ). , a die hole diameter of 0.50 mm and a die length of 1.00 mm. The viscosity η was calculated from the following formula. In the formula, Q is the flow rate of the sealing epoxy resin composition per unit time. The unit in Table 2 is Pa·second.
η=(4πDP/128LQ)×10 ⁻³ (Pa·sec)
η: apparent viscosity D: die hole diameter (mm)
P: test pressure (Pa)
L: Die length (mm)
Q: flow rate (cm ³ /sec)

(Shrinkage factor)
For each of the sealing epoxy resin compositions of Examples and Comparative Examples, the heating conditions (PMC : Post Mold Cure). First, the dimensions of the disk-shaped mold were measured at four points at room temperature, and the average value was calculated. Subsequently, the encapsulating epoxy resin composition was put into a mold to obtain a disk-shaped cured product, and the obtained cured product was subjected to heat treatment, and then the diameter at room temperature was measured with the mold. Measurement was performed at four locations corresponding to the locations where the measurement was performed, and the average value was calculated. Next, the obtained average value is applied to the following formula: [(mold dimension at room temperature - dimension at room temperature of cured product after heat treatment)/mold dimension at room temperature] x 100 (%), and the cured product A shrinkage rate S _n (%) was calculated.
Table 2 shows the results. The temperature conditions assuming resin sealing were 175° C. and 180 seconds, and the temperature conditions assuming main curing were 175° C. and 4 hours.

(granule density)
The obtained granular epoxy resin composition for sealing is sieved for 20 minutes using a JIS standard sieve with an opening of 106 μm equipped with a low-tap sieve vibrator (manufactured by Marubishi Kagaku Kikai Seisakusho, model SS-100A). The sample was sifted through a sieve while vibrating (hammer strikes: 120/min) through a sieve to remove fines less than 106 μm. Next, after sieving the granular resin composition with a JIS standard sieve of 32 mesh (500 μm opening), about 5 g of the granular resin composition on the sieve was weighed to 0.1 mg to obtain a sample. After filling a pycnometer (capacity 50 cc) with distilled water and adding a few drops of surfactant, the weight of the pycnometer containing distilled water and surfactant was measured. Next, put the sample into the pycnometer, measure the mass of the entire pycnometer containing the distilled water, the surfactant and the sample, and calculate according to the following formula.
Granule density (g/ml) = (Mp x ρw)/(Mw + Mp-Mt)
ρw: Density of distilled water at the temperature at the time of measurement (g/ml)
Mw: Mass (g) of pycnometer filled with distilled water and added with a few drops of surfactant
Mp: Mass of sample (g)
Mt: Mass (g) of pycnometer containing distilled water, surfactant and sample

10 Base material 20 Copper pillar 21 Electronic component 22 Bump 30 Sealing material layer 50 Electronic device 80 Rewiring insulating layer 92 Via 94 Rewiring circuit 96 Solder ball 98 Solder resist layer 100 Electronic device 140 Semiconductor chip

Claims (12)

An epoxy resin composition comprising an epoxy resin, a curing agent, and a thermally expandable filler having a core-shell structure,
the thermally expandable filler comprises a volatile expansion agent inside a shell in the core-shell structure;
An epoxy resin composition for sealing, wherein the epoxy resin composition is in the form of granules and is for compression molding . 2. The epoxy resin composition for sealing according to claim 1, wherein the volume expansion coefficient of said epoxy resin composition measured under the following conditions is 100% or more.
(conditions)
0.20 g of the epoxy resin composition for sealing is taken out, placed in an aluminum cup with an inner diameter of 53 mm, and photographed from right above the aluminum cup. The obtained image is binarized, and the ratio of the area G _A (mm ² ) of the portion covered with the sealing epoxy resin composition to the area D (mm ² ) of a circle with an inner diameter of 53 mm is shown. , to calculate the area ratio R _A =G _A /D. Subsequently, the aluminum cup containing the epoxy resin composition is heated at 175° C. for 3 minutes, and a photograph is taken again from directly above the aluminum cup. The resulting image was binarized, and the area ratio of the area G _B (mm ² ) of the portion covered with the sealing epoxy resin composition to the area D (mm ² ) of a circle with an inner diameter of 53 mm. The area ratio _RB = _GB /D is calculated. A coverage C is calculated from the ratio of the area ratio R _A and the area ratio R _B .
Formula (1) coverage C=R _B /R _A
Subsequently, the volume expansion coefficient E of the epoxy resin composition was calculated according to formula (2).
Formula (2) Volume expansion rate E (%) = C ^(3/2) × 100 3. The epoxy resin composition for sealing according to claim 1, wherein the thermally expandable filler has an average particle size of 1 μm or more and 200 μm or less as measured by a laser diffraction particle size distribution analyzer. The encapsulating epoxy resin composition of any one of claims 1-3, wherein the volatile swelling agent comprises a hydrocarbon. The sealing epoxy resin composition according to any one of claims 1 to 4, wherein the volatile swelling agent contains a hydrocarbon having a boiling point of -30°C or higher and 175°C or lower. The epoxy resin composition for sealing according to any one of claims 1 to 5, wherein the shell in the core-shell structure contains a thermoplastic resin. The thermoplastic resin includes a structural unit derived from vinylidene chloride, a structural unit derived from a nitrile-based monomer, a structural unit derived from a (meth)acrylic acid ester-based monomer, a structural unit derived from a monomer having an amide group, and 7. The sealing epoxy resin composition according to claim 6, comprising a polymer having at least one structural unit selected from the group consisting of a structural unit derived from a monomer having a glycidyl group in the molecule. Any one of claims 1 to 7, wherein the expansion start temperature of the sealing epoxy resin composition obtained by the following <method> using DMA (dynamic viscoelasticity measurement) is 50°C or higher and 175°C or lower. 1. The epoxy resin composition for encapsulation according to item 1.
<Method>
0.5 mg of the epoxy resin composition for sealing was placed in an aluminum cup with a diameter of 6.0 mm and a depth of 4.8 mm, an aluminum lid was placed on top of the epoxy resin composition for sealing, and the sample was applied from above. The height of the sample is measured with a force of 0.01N applied by the indenter. In this state, the material is heated from 20° C. to 300° C. at a rate of temperature increase of 10° C./min, the amount of displacement in the vertical direction of the pressurizer is measured, and the positive displacement start temperature is taken as the expansion start temperature. Any one of claims 1 to 8, wherein the maximum expansion temperature of the sealing epoxy resin composition obtained by the following <Method> using DMA (dynamic viscoelasticity measurement) is 80°C or higher and 180°C or lower. 1. The epoxy resin composition for encapsulation according to item 1.
<Method>
0.5 mg of the epoxy resin composition for sealing was placed in an aluminum cup with a diameter of 6.0 mm and a depth of 4.8 mm, an aluminum lid was placed on top of the epoxy resin composition for sealing, and the sample was applied from above. The height of the sample is measured with a force of 0.01N applied by the indenter. In this state, the material is heated from 20° C. to 300° C. at a rate of temperature increase of 10° C./min, the amount of displacement in the vertical direction of the pressurizer is measured, and the temperature at which the maximum amount of displacement is obtained is defined as the maximum expansion temperature. The encapsulating epoxy resin composition according to any one of claims 1 to 9 , having an average particle size of 1 mm or less. The sealing epoxy resin composition according to any one of claims 1 to 10 ,
An encapsulating epoxy resin composition used for encapsulating electronic components. An electronic device comprising a cured film of the sealing epoxy resin composition according to any one of claims 1 to 11 .

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