JP2022117398A - Resin composition for encapsulation, method for manufacturing semiconductor device, and method for detecting hollow inorganic filler - Google Patents

Abstract

To provide a sealing resin composition capable of suppressing deletion/breakage of a hollow inorganic filler.SOLUTION: The sealing resin composition of the present invention contains an epoxy resin (A) and an inorganic filler (B). The inorganic filler (B) contains a hollow inorganic filler (b1). The proportion of a hollow inorganic filler having a diameter of hollow size of 20 μm or more in the hollow inorganic filler (b1) is 5 pieces or less per 1 mg of the sealing resin composition, and the maximum diameter of the hollow size is 45 μm or less.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to an encapsulating resin composition, a method for manufacturing a semiconductor device, and a method for detecting hollow inorganic fillers.

2. Description of the Related Art Conventionally, in an integrated circuit package in which a semiconductor chip such as a semiconductor integrated circuit is packaged, there is an increasing demand for miniaturization and thinning. In recent years, for example, a CSP obtained by performing a singulation process on a structure including a plurality of semiconductor devices formed on a semiconductor wafer by a wafer process is called a WCSP (Wafer Level Chip Size Package). has introduced a multilayer rewiring structure for higher integration.

Hollow inorganic particles are used in the resin composition used as a material for forming the insulating layer of such a semiconductor device in order to reduce the dielectric constant and linear thermal expansion coefficient of the cured product of the resin composition. (Patent Document 1).
In addition, in Patent Document 1, in order to suppress the cracking of the hollow particles in the process until the insulating layer is obtained, the hollow inorganic particles of the resin composition are formed of an inorganic composite oxide. It is disclosed that the porosity of the particles is 25% by volume or more and the average particle diameter of the hollow inorganic particles is specified to be 5.0 μm or less.

JP 2020-083966 A

However, even when hollow inorganic particles as disclosed in Patent Document 1 are used, sufficient filling properties cannot be obtained when resin sealing is performed using a resin composition containing the hollow inorganic particles. was there. In addition, when an insulating layer is produced, when the insulating layer is ground to form a rewiring layer, part of the hollow inorganic particles are lost or broken, and recesses are likely to occur on the ground surface. When the rewiring layer is formed on the insulating layer, there is a problem that the rewiring layer is broken, and the electrical reliability of the obtained semiconductor device is impaired.
Therefore, the present inventors conducted further studies and found that controlling the hollow size of the hollow inorganic particles is effective for further improving the filling properties of the encapsulating resin composition containing the hollow inorganic particles. I found

According to the invention,
A sealing resin composition containing an epoxy resin (A) and an inorganic filler (B),
The inorganic filler (B) comprises a hollow inorganic filler (b1),
A resin for sealing, wherein the proportion of the hollow inorganic filler (b1) having a hollow size of 20 μm or more per 1 mg of the sealing resin composition is 5 or less, and the maximum diameter of the hollow size is 45 μm or less. A composition is provided.

Moreover, according to the present invention,
Provided is a semiconductor device comprising an insulating layer made of the above encapsulating resin composition.

Moreover, according to the present invention,
A step of forming an insulating layer made of the above sealing resin composition on a substrate;
grinding the insulating layer;
and forming a wiring layer on the ground surface of the insulating layer.

Moreover, according to the present invention,
A hollow inorganic filler detection method comprising dispersing the inorganic filler (B) in a liquid and detecting the hollow inorganic filler (b1) with an image analysis particle size distribution analyzer,
A method for detecting a hollow inorganic filler is provided, wherein the ratio (ns/nf) of the refractive index ns of the liquid to the refractive index nf of the inorganic filler (B) is 0.98 to 1.02.

ADVANTAGE OF THE INVENTION According to this invention, the method which can detect the resin composition for sealing with a favorable filling property, and a hollow inorganic particle with high precision can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The drawings are for illustrative purposes only. The shape and dimensional ratio of each member in the drawings do not necessarily correspond to the actual article.

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".

<Resin composition for encapsulation>
The encapsulating resin composition of the present embodiment contains an epoxy resin (A) and an inorganic filler (B), and the inorganic filler (B) contains a hollow inorganic filler (b1). In the hollow inorganic filler (b1), the ratio of hollow inorganic fillers having a hollow size of 20 μm or more in diameter is 5 or less per 1 mg of the sealing resin composition, and the maximum diameter of the hollow size is 45 μm or less. .
Here, according to the present inventors, when a large number of hollow inorganic fillers having a large hollow size are contained in a resin composition for sealing containing hollow inorganic fillers, the inorganic fillers are uniformly dispersed due to differences in specific gravities and the like. It was found that the filling property of the encapsulating resin composition deteriorated. In addition, hollow inorganic fillers are inferior in strength to solid inorganic fillers that do not have hollows. or may be easily damaged.
Therefore, in the encapsulating resin composition of the present embodiment, focusing on the hollow size of the hollow inorganic filler (b1), the ratio of the hollow inorganic filler having a hollow size of 20 μm or more in diameter per 1 mg of the encapsulating resin composition By specifying the maximum diameter of the hollow size to be 45 μm or less while controlling the number to 5 or less, the uniform dispersibility of the inorganic filler (B) can be improved, and the filling property of the sealing resin composition can be improved. In the semiconductor manufacturing process using, the hollow inorganic filler (b1) can be more highly inhibited from being lost or damaged.

In the present embodiment, the hollow inorganic filler is intended to mean an inorganic filler having a closed space inside, and is different from a porous inorganic filler having many fine cavities. In the present embodiment, the closed mass space means a space of 0.5 μm ³ (corresponding to the volume of a sphere with a diameter of 1 μm) or more.

Each component contained in the encapsulating resin composition of the present embodiment will be described below.

[Epoxy resin (A)]
Epoxy resin (A) is used as a thermosetting resin in a sealing resin composition, and may be any monomer, oligomer, or polymer having two or more epoxy groups in one molecule. and molecular structure are not particularly limited.
Specific examples of the epoxy resin (A) include biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol type epoxy resins such as tetramethylbisphenol F type epoxy resins, stilbene type epoxy resins, and hydroquinone. crystalline epoxy resins such as type epoxy resins; novolak type epoxy resins such as cresol novolac type epoxy resins, phenol novolac type epoxy resins, and naphthol novolak type epoxy resins; phenylene skeleton-containing phenol aralkyl type epoxy resins, biphenylene skeleton-containing phenol aralkyl type epoxy Aralkyl epoxy resins such as resins, naphthol aralkyl epoxy resins containing a phenylene skeleton, and phenol aralkyl epoxy resins containing an alkoxynaphthalene skeleton; trifunctional epoxy resins such as triphenolmethane epoxy resins and alkyl-modified triphenolmethane epoxy resins; modified phenol-type epoxy resins such as cyclopentadiene-modified phenol-type epoxy resins and terpene-modified phenol-type epoxy resins; and heterocyclic ring-containing epoxy resins such as triazine nucleus-containing epoxy resins. These may be used individually by 1 type, and may be used in combination of 2 or more types. Among these, it is more preferable to use at least one of a novolac epoxy resin and a trifunctional epoxy resin from the viewpoint of achieving both storage stability and low-temperature curability and improving moldability.
In addition, the epoxy resin (A) preferably contains an epoxy resin having an epoxy equivalent of 160 g/eq or more and 250 g/eq or less, more preferably an epoxy resin having an epoxy equivalent of 180 g/eq or more and 220 g/eq or less. preferable. This makes it easier to improve the balance between storage stability and low-temperature curability.

The content of the epoxy resin (A) is not particularly limited. more preferably 5% by mass or more and 20% by mass or less.
By setting the content of the epoxy resin (A) to the above lower limit or more, the fluidity and moldability of the encapsulating resin composition can be more effectively improved. Further, by setting the content of the epoxy resin (A) to the above upper limit or less, the storage stability and low-temperature curability can be improved more effectively.

[Inorganic filler (B)]
The inorganic filler (B) contains a hollow inorganic filler (b1). The hollow inorganic filler (b1) is part of the inorganic filler (B) contained in the encapsulating resin composition that is hollow.

The inorganic filler (B) is used to increase mechanical strength and impart heat resistance, flame retardancy, and the like.
Specific examples of the inorganic filler (B) include, for example, talc, calcined clay, uncalcined clay, mica, silicates such as glass; titanium oxide, alumina, boehmite, silica and other oxides; calcium carbonate, magnesium carbonate, carbonates such as hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, calcium sulfite; zinc borate, barium metaborate, boron borate salts such as aluminum oxide, calcium borate and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride and carbon nitride; titanates such as strontium titanate and barium titanate. These may be used individually by 1 type, and may use 2 or more types together.
Among them, silica is preferable as the inorganic filler (B).

Examples of the silica include crystalline silica (crushed crystalline silica) and fused silica (crushed amorphous silica, spherical amorphous silica). Among them, fused spherical silica is preferable from the viewpoint of improving electrical reliability and facilitating sealing.

The cumulative 50% value of the volume-based particle size distribution of the inorganic filler (B), that is, the average particle size D50 is preferably 0.1 to 100 μm, more preferably 0.2 to 80 μm, and still more preferably 0.2 μm. 3 to 50 μm, more preferably 0.4 to 15 μm.
The mechanical strength of the inorganic filler (B) and the hollow inorganic filler (b1) can be increased by setting the average particle diameter D50 of the inorganic filler (B) to the above lower limit or more. On the other hand, by setting the average particle diameter D50 of the inorganic filler (B) to the above upper limit or less, the filling property can be enhanced.

Moreover, the inorganic filler (B) preferably has two or more peaks in the volume-based particle size distribution. That is, it is preferable to use two or more kinds of inorganic fillers having different average particle diameters. This makes it easier to improve the filling property while suppressing loss and breakage of the hollow inorganic filler (b1).
Furthermore, the inorganic filler (B) preferably has one or more peaks in the volume-based particle size distribution in the range of 0.1 µm or more and less than 3 µm and in the range of 3 µm or more and 100 µm or less.

The volume-based particle size distribution of the inorganic filler (B) can be measured with a commercially available laser particle size distribution analyzer (eg, SALD-7000 manufactured by Shimadzu Corporation). Thereby, the outer diameter of the inorganic filler (B) can be measured.

The content of the inorganic filler (B) is not particularly limited. more preferably 80% by mass or more and 90% by mass or less.
By setting the content of the inorganic filler (B) to the above lower limit or more, it is possible to effectively improve the storage stability and curability of the sealing resin composition. In addition, by setting the content of the inorganic filler (B) to the above upper limit or less, it is possible to improve the fluidity of the encapsulating resin composition and improve the moldability more effectively.

The inorganic filler (B) may be surface-treated with a surface-treating agent from the viewpoint of dispersing it in the resin component without aggregating the primary particle size.

[Hollow inorganic filler (b1)]
In the hollow inorganic filler (b1), the proportion of hollow inorganic fillers having a hollow size of 20 µm or more in diameter is 5 or less per 1 mg of the sealing resin composition, and the maximum diameter of the hollow size is 45 µm or less. The hollow inorganic filler (b1) is the inorganic filler (B) contained in the encapsulating resin composition that is hollow. In the hollow inorganic filler (b1), the proportion of hollow inorganic fillers having a hollow size of 5 μm or more and less than 20 μm in diameter is preferably 1 or more and 200 or less per 1 mg of the sealing resin composition.
As a result, while increasing the filling property of the encapsulating resin composition, partial loss or damage of the hollow inorganic filler (b1) when manufacturing a semiconductor device using the encapsulating resin composition of the present embodiment can be suppressed, and the reliability of the semiconductor device can be improved.

In order to obtain the hollow inorganic filler (b1) of the present embodiment, it is important to devise the following manufacturing method.
For example, the inorganic filler (B) is classified by a dry classification method, a wet classification method, or a combination thereof. The dry classification methods include gravimetric field classification, inertial force field classification, free vortex centrifugal field classification, and forced vortex centrifugal field classification. Examples of the wet classifying method include a gravitational field classifying method, a free vortex type centrifugal field classifying method, and a forced vortex type centrifugal field classifying method. The classification method to be used can be appropriately selected depending on the type of inorganic filler (B).

From the viewpoint of workability, it is preferable to use a dry classification method, and from the viewpoint of controlling the particle size distribution and the hollow inorganic filler (b1), a gravitational field classification method, an inertial force field classification method, a free vortex type It is preferable to use a combination of either the centrifugal field classification method or the forced vortex type centrifugal field classification method. These classification methods are carried out using commercially available equipment.

For the measurement of the hollow size of the hollow inorganic filler (b1), for example, a wet dispersion type image analysis particle size distribution analyzer can be used. In addition, it is effective to use a method for detecting hollow inorganic fillers, which will be described later, for measuring the proportion of hollow inorganic fillers having a diameter of 20 μm or more.

The encapsulating resin composition of the present embodiment may further contain the following components.

[Curing agent (C)]
The encapsulating resin composition of the present embodiment can contain a curing agent (C). The curing agent (C) is not particularly limited as long as it can be cured by reacting with the thermosetting resin (A). linear aliphatic diamines of numbers 2 to 20, as well as metaphenylenediamine, paraphenylenediamine, paraxylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodicyclohexane, bis(4-aminophenyl)phenylmethane, 1,5-diaminonaphthalene, metaxylenediamine, paraxylenediamine, 1,1-bis(4 -aminophenyl)cyclohexane, amines such as dicyanodiamide; resol-type phenol resins such as aniline-modified resole resin and dimethyl ether resole resin; Resins: phenol aralkyl resins such as phenylene skeleton-containing phenol aralkyl resins and biphenylene skeleton-containing phenol aralkyl resins; phenol resins having condensed polycyclic structures such as naphthalene skeletons and anthracene skeletons; polyoxystyrenes such as polyparaoxystyrene; hexahydrophthalic anhydride acid (HHPA), alicyclic acid anhydrides such as methyltetrahydrophthalic anhydride (MTHPA), aromatic acids such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenonetetracarboxylic acid (BTDA) acid anhydrides including anhydrides; polymercaptan compounds such as polysulfides, thioesters and thioethers; 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, and may be used in combination of 2 or more types. Among these, it is more preferable to use at least one of the novolak-type phenol resin and the phenol aralkyl resin from the viewpoint of realizing low-temperature sealing of the resin composition for sealing.

The content of the curing agent (C) in the encapsulating resin composition is not particularly limited. , more preferably 1% by mass or more and 8% by mass or less.
By making the content of the curing agent (C) equal to or higher than the above lower limit, it becomes easier to appropriately cure the encapsulating resin composition. On the other hand, by setting the content of the curing agent (C) to the above upper limit or less, it becomes easy to maintain appropriate fluidity and achieve sealing.

[Curing accelerator (D)]
The curing accelerator (D) of this embodiment acts as a catalyst. Examples of the curing accelerator (D) include phosphorus atom-containing compounds such as organic phosphines, tetrasubstituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, or adducts of phosphonium compounds and silane compounds. amidine compounds such as 1,8-diazabicyclo(5,4,0)undecene-7 and imidazole; nitrogen atom-containing compounds such as tertiary amines such as benzyldimethylamine, amidinium salts, or ammonium salts; phenol, bisphenol A , nonylphenol, and 2,3-dihydroxynaphthalene. Examples of the organic phosphine include triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium/tetraphenylborate, triphenylphosphine/triphenylborane, 1,2-bis-(diphenylphosphino)ethane, and the like. be done.
Among them, the curing accelerator (D) is preferably an organic phosphine or a phenol compound.

The content of the curing accelerator (D) in the encapsulating resin composition is not particularly limited. It is preferably 0.2% by mass or more and 2% by mass or less.
By setting the content of the curing accelerator (D) to the above lower limit or more, it becomes easier to appropriately cure the encapsulating resin composition. On the other hand, by setting the content of the curing accelerator (D) to the above upper limit or less, the melted state can be prolonged and the low-viscosity state can be prolonged.

[Coupling agent (E)]
The encapsulating resin composition can contain, for example, a coupling agent (E). Examples of the coupling agent (E) include various silane compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, titanium compounds, aluminum chelates, aluminum/zirconium compounds, and other known cups. A ring agent can be used.
More specifically, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrisilane. Methoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane silane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ-[bis(β-hydroxyethyl )] aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, N-β-(aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-(β-aminoethyl)aminopropyldimethoxymethylsilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethyl) silylisopropyl)ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyl Disilane, Vinyltrimethoxysilane, γ-Mercaptopropylmethyldimethoxysilane, 3-Isocyanatopropyltriethoxysilane, 3-Acryloxypropyltrimethoxysilane, 3-Triethoxysilyl-N-(1,3-dimethyl-butylidene) Silane-based coupling agents such as hydrolysates of propylamine; isopropyl triisostearoyl titanate, isopropyl tris(dioctylpyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) ) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctylpyro phosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctylphosphate) titanate, Titanate-based coupling agents such as isopropyltricumylphenyltitanate, tetraisopropylbis(dioctylphosphite)titanate and the like are included. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the coupling agent (E) in the encapsulating resin composition is not particularly limited. It is preferably 0.1% by mass or more and 2% by mass or less. By setting the content of the coupling agent (E) to the above lower limit or more, the dispersibility of the inorganic filler (B) in the encapsulating resin composition can be improved. Further, by setting the content of the coupling agent (E) to the above upper limit or less, the fluidity of the encapsulating resin composition can be improved and the moldability can be improved.

Furthermore, the resin composition for sealing of the present embodiment includes, in addition to the above components, thermosetting resins such as phenol resins other than the above epoxy resins, epoxy resins, unsaturated polyester resins, melamine resins, and polyurethane; Colorants such as black; Release agents such as natural wax, synthetic wax, higher fatty acids or metal salts thereof, paraffin, and polyethylene oxide; Ion scavengers such as hydrotalcite; Low stress agents such as silicone oil and silicone rubber; Flame retardants such as aluminum oxide; various additives such as antioxidants may be included.

<Method for producing encapsulating resin composition>
The encapsulating resin composition of the present embodiment can be obtained by a known method. A varnish-like composition can be prepared by dissolving, mixing, and stirring in a solvent using various mixers such as a dispersing method or a rotation-revolution dispersing method.

Specific examples of solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, heptane, cyclohexane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethylsulfoxide, ethylene glycol, cellosolve, carbitol, and anisole. , and N-methylpyrrolidone. A solvent may be used individually by 1 type, or may be used in combination of 2 or more type.

<Semiconductor device and its manufacturing method>
The semiconductor device of the present embodiment is obtained using the above-described sealing resin composition, and includes an insulating layer made of the above-described sealing resin composition.
Thereby, a semiconductor device having excellent electrical reliability can be obtained.

The manufacturing method of the semiconductor device of this embodiment includes the following steps.
Step 1: a step of forming an insulating layer made of the sealing resin composition of the present embodiment on a substrate;
Step 2: grinding the insulating layer;
Step 3: Step of Forming a Wiring Layer on the Grinded Surface of the Insulating Layer Each step will be described in detail below.

[Step 1]
The step of forming the insulating layer includes a step of coating the sealing resin composition on the substrate by a spin coating method, a printing method, or the like to form a film. The film thickness of the insulating layer can be 0.1 to 30 μm. The insulating layer has openings corresponding to the electrode pads. Thereby, the rewiring layer formed on the insulating layer is electrically connected to the pad.

[Step 2]
The step of grinding the insulating layer is performed, for example, by a grinding method using a grindstone rotating at high speed. In the present embodiment, the insulating layer contains the hollow inorganic filler (b1), and in the hollow inorganic filler (b1), the ratio of the hollow inorganic filler having a hollow size of 20 μm or more in diameter is 5 per 1 mg of the sealing resin composition. and the maximum diameter of the hollow size is controlled to 45 μm or less. As a result, loss of the hollow inorganic filler (b1) due to grinding is suppressed, and as a result, a smooth ground surface can be easily obtained.
Prior to the grinding step, the insulating layer may be surface-treated by a plasma treatment method, if desired. The roughness Ra of the ground surface of the insulating layer measured with a laser microscope at a magnification of 50 can be 0.3 or less, preferably 0.2 or less, and more preferably 0.1 or less.

[Step 3]
The rewiring layer is obtained by forming a metal film using a vacuum deposition method, a sputtering method, an electrolytic plating method, an electroless plating method, or the like.

The method of manufacturing a semiconductor device according to the present embodiment further includes steps of forming external connection terminals and singulating.

<Method for detecting hollow inorganic filler>
The method for detecting the hollow inorganic filler of the present embodiment comprises dispersing the inorganic filler (B) in a liquid and detecting the hollow inorganic filler (b1) with an image analysis particle size distribution meter. A ratio of the refractive index ns of the liquid to the refractive index nf (ns/nf) is specified between 0.98 and 1.02.
Here, when a solid that is insoluble in a certain liquid is dispersed in the liquid and the refractive index of the solid is approximately the same as the refractive index of the liquid, the solid is hardly visible in the liquid. Therefore, the liquid in which the solid is dispersed is recognized as transparent.
Therefore, the inventors of the present invention have found a method for detecting the hollow inorganic filler contained in the inorganic filler (B) used in the resin composition for sealing. For the first time, we focused on controlling the That is, taking advantage of the fact that the inorganic filler (B) does not substantially dissolve in the liquid, the ratio (ns/nf) of the refractive index ns of the liquid to the refractive index nf of the inorganic filler (B) is 0.98 to 1.02. By making the inorganic filler (B) dispersed in the liquid less visible from the outside, the hollow inorganic filler (b1) is hollow inside, so the inorganic filler (B) has a refractive index of It was confirmed for the first time that it is visible from the outside even if it is placed in a liquid because it is different. Specifically, the liquid containing the hollow inorganic filler (b1) is observed as cloudy, and the presence of the hollow inorganic filler (b1) can be confirmed. That is, according to the hollow inorganic filler detection method of the present embodiment, the hollow inorganic filler (b1) contained in the inorganic filler (B) can be easily detected.

The liquid used in the detection method of the present embodiment is not particularly limited as long as it does not substantially dissolve the inorganic filler. Examples of the liquid include glycerin, toluene, acetone, methyl alcohol, water, and ethyl alcohol. , methyl ethyl ketone, and chloroform. Among them, a mixed liquid containing two or more kinds is preferable, and a mixed liquid containing toluene is more preferable. This makes it easier to control ns/nf.

Further, in the method for detecting the hollow inorganic filler of the present embodiment, the refractive index of the inorganic filler (B) is preferably 1.35 to 1.55, more preferably 1.40 to 1.50. It is preferably 1.42 to 1.49, and more preferably 1.42 to 1.49. This makes it easier to detect the hollow inorganic filler (b1) with higher accuracy.

Further, in the method for detecting the hollow inorganic filler of the present embodiment, even if the inorganic filler (B) is contained in the encapsulating resin composition, the hollow inorganic filler (b1) can be easily detected. . In this case, the hollow inorganic filler (b1) may be detected by burning the sealing resin composition containing the inorganic filler (B) and dispersing the remaining ash in the liquid. The combustion conditions for the sealing resin composition are not particularly limited as long as the sealing resin composition is completely burned. For example, it is preferable to use a muffle furnace at 600 to 800° C. for 2 to 4 hours. . A muffle furnace is a furnace in which a partition wall (muffle) made of a refractory material with good thermal conductivity is installed between a heat source or heating element and a firing chamber.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can be adopted. Moreover, the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.

Embodiments of the present invention will be described in detail based on examples and comparative examples. In addition, the present invention is not limited to the examples.

[raw materials]
The following materials were used as raw materials for the encapsulating resin composition.
Epoxy resin (A)
- A mixture of a triphenylmethane-type epoxy resin and a biphenyl-type epoxy resin (YL6677, manufactured by Mitsubishi Chemical Corporation)
Inorganic filler (B)
・Silica 1: Spherical silica (TS-6026, manufactured by Micron, average particle size 9.0 μm, specific surface area 3.4 m ² /g, sieved with a mesh size of 20 μm to remove particles of 20 μm or more (hereinafter referred to as “upper limit cut 20 μm”.))
・ Silica 2: Spherical silica (SC2500-SQ, manufactured by Admatechs, average particle diameter 0.5 μm, specific surface area 6.0 m ² /g, upper limit cut 45 μm)
・ Silica 3: Spherical silica (SC5500-SQ, manufactured by Admatechs, average particle size 1.5 μm, specific surface area 5.5 m ² /g, upper limit cut 45 μm)
・ Silica 4: Spherical silica (SC5503-SQ, manufactured by Admatechs, average particle size 1.5 μm, specific surface area 6.0 m ² /g, upper limit cut 5 μm)
Curing agent (C)
Curing agent 1: Phenolic resin having a triphenylmethane skeleton (manufactured by Air Water, HE910-20, hydroxyl equivalent 101 g/eq)
Curing accelerator (D)
・ Catalyst 1: triphenylphosphine (PP-360 manufactured by K.I Kasei Co., Ltd.)
・ Catalyst 2: 2,3-dihydroxynaphthalene (manufactured by Air Water)
Coupling agent (E)
Coupling agent 1: N-phenyl-γ-aminopropyltrimethoxysilane (CF-4083 manufactured by Dow Corning Toray Co., Ltd.)
Coupling agent 2: γ-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-803)
Other ・Low stress agent: Carboxyl group-terminated butadiene-acrylonitrile copolymer (CTBN1008SP, manufactured by Ube Industries, Ltd.)
・ Ion scavenger: hydrotalcite (manufactured by Kyowa Kagaku Co., Ltd., DHT-4H)
・Wax: Oxidized polyethylene wax (Ricowax PED191, manufactured by Clariant Japan)
・ Coloring agent: carbon black (manufactured by Mitsubishi Chemical Corporation, #5)

[Measurement and detection of hollow inorganic filler]
Using the inorganic filler (B), the hollow inorganic filler was measured and detected according to the following procedure. Table 2 shows the results.
An image analysis particle size distribution meter (IF-3200, manufactured by Jusco International Co., Ltd.) was used as a hollow filler detection device.
First, a test liquid having a concentration of each inorganic filler (B) of 30 mg/mL was prepared using a mixed liquid adjusted toluene:acetone=3:1 (weight ratio) as a dispersion medium. After that, the obtained test solution was subjected to ultrasonic treatment for 2 minutes.
Each test liquid was image-detected by the above detection device, and the number of hollow fillers in the inorganic filler (B) was counted. Also, the maximum diameter of each hollow size was measured and the average value was obtained.
The lens magnification of the detector was 1.5 times, and the thickness of the spacer at the measuring portion was 300 μm. Images were taken repeatedly using a CMOS camera mounted on the device until an amount corresponding to 17 mg of silica was obtained, and the obtained images were analyzed. In order to extract only hollow fillers from the obtained images, only results with a circularity of 95% or more were extracted and analyzed.

<Example/Comparative example>
For each example and comparative example, each component was dissolved or dispersed at the solid content ratio shown in Table 1, adjusted with methyl ethyl ketone so that the nonvolatile content was 70% by mass, and stirred using a high-speed stirring device to form a varnish-like seal. A stopping resin composition was prepared.

<Measurement/Evaluation>
Each encapsulating resin composition thus obtained was evaluated and measured as follows.

- Evaluation of fillability defect rate A thermal release sheet (3195V, manufactured by Nitto Denko) was attached to a 12-inch silicon wafer. Next, each encapsulating resin composition was molded to have a molding thickness of 150 μm. The molding conditions were 130° C. and 600 seconds. A semi-automatic type CPM1080 (manufactured by TOWA) was used as a molding device for molding. After 10 shots were molded, the appearance of the molded product was visually confirmed, and the number of unfilled portions remaining at the ends was counted.

-Evaluation of Rewiring Layer Defect Rate Each encapsulating resin composition was molded onto a 12-inch silicon wafer so as to have a molding thickness of 500 μm. The molding conditions were 130° C. and 600 seconds. A semi-automatic type CPM1080 (manufactured by TOWA) was used as a molding device for molding. After molding, the surface was ground by about 100 μm using DFG8560 (grinding device, manufactured by Disco) and GF01-SD4000 (grind wheel, #4000). A photosensitive resin material "CRC-8600 (manufactured by Sumitomo Bakelite Co., Ltd.)" for a rewiring layer was applied to the shaved surface using a spin coater with a target of 10 μm, and dried at 120 ° C. for 5 minutes using a hot plate. .
The coated surface was observed using a microscope, and portions with coating defects of 20 μm or more were judged to be defective. The number of defects in one shot was measured and compared.
When hollow fillers are present, they tend to appear as defects on the coating surface. If there is a coating defect, there is a tendency to cause poor conduction during the formation of the rewiring layer.

Claims (12)

A sealing resin composition containing an epoxy resin (A) and an inorganic filler (B),
The inorganic filler (B) comprises a hollow inorganic filler (b1),
A resin for sealing, wherein the proportion of the hollow inorganic filler (b1) having a hollow size of 20 μm or more per 1 mg of the sealing resin composition is 5 or less, and the maximum diameter of the hollow size is 45 μm or less. Composition. 2. The encapsulating resin composition according to claim 1, wherein the inorganic filler (B) has an average particle size D50 of 0.1 to 100 μm based on volume-based particle size distribution. The encapsulating resin composition according to claim 1 or 2, wherein the inorganic filler (B) has two or more peaks in the volume-based particle size distribution. 3. Any one of claims 1 to 3, wherein the inorganic filler (B) has one or more peaks in the volume-based particle size distribution in the range of 0.1 μm or more and less than 3 μm and in the range of 3 μm or more and 20 μm or less. 3. The encapsulating resin composition according to Item 1. 5. The encapsulating resin composition according to any one of claims 1 to 4, wherein the inorganic filler (B) has a refractive index of 1.35 to 1.55. The sealing resin composition according to any one of claims 1 to 5, wherein the inorganic filler (B) contains silica. A semiconductor device comprising an insulating layer made of the encapsulating resin composition according to any one of claims 1 to 6. A step of forming an insulating layer made of the encapsulating resin composition according to any one of claims 1 to 6 on a substrate;
grinding the insulating layer;
and forming a wiring layer on the ground surface of the insulating layer. 9. The method of manufacturing a semiconductor device according to claim 7, wherein said step of forming a wiring layer is performed by a spin coating method or a printing method. A hollow inorganic filler detection method comprising dispersing the inorganic filler (B) in a liquid and detecting the hollow inorganic filler (b1) with an image analysis particle size distribution analyzer,
A method for detecting a hollow inorganic filler, wherein the ratio (ns/nf) of the refractive index ns of the liquid to the refractive index nf of the inorganic filler (B) is 0.98 to 1.02. Detection of the hollow inorganic filler according to claim 10, wherein the liquid is a liquid containing one or more selected from glycerin, toluene, acetone, methyl alcohol, water, ethyl alcohol, methyl ethyl ketone, and chloroform. Method. 12. The method for detecting a hollow inorganic filler according to claim 10 or 11, wherein the inorganic filler (B) is ash obtained by burning the sealing resin composition according to any one of claims 1 to 6.