JP6339060B2 - Epoxy resin composition for sealing, and method for producing electronic device using the same - Google Patents

Description

  The present invention relates to an epoxy resin composition for sealing, a method for producing an electronic device using the same, and the electronic device.

  Conventionally, a technique for sealing a semiconductor element by compression molding using an epoxy resin composition for sealing is known. As a conventional epoxy resin composition for sealing, there exists what was described in patent document 1, for example.

  Patent Document 1 describes a sealing resin composition having an epoxy resin, a curing agent, a curing accelerator, and a filler as essential components and a disc flow of 70 mm or more. Patent Document 1 describes that the fluidity in a low shear region that cannot be evaluated by spiral flow can be measured by disk flow. For this reason, it is said that a specific electronic component device with excellent chip resistance, reflow crack resistance and void resistance, and excellent reliability can be obtained by a specific sealing epoxy resin molding material that defines a disc flow.

JP 2002-146161 A

  However, the technique described in the above document has a problem that the bonding wire is deformed when sealing and molding an element such as a semiconductor element.

  According to the knowledge of the present inventors, the flowability of the epoxy resin composition in the low shear region under the initial low pressure from the state where the epoxy resin composition slowly melts on the mold under substantially no pressure. However, it became clear that the quality of wire deformation was affected. However, as described in Patent Document 1, the flowability of the low shear region epoxy resin composition could not be evaluated by the conventional spiral flow. Patent Document 1 describes that the disk flow can measure the fluidity in the low shear region, but in order to determine the quality of the wire deformation, the epoxy in the lower shear rate region is described. The present inventors thought that it was necessary to evaluate the viscosity of a resin composition.

  This invention is made | formed in view of the said situation, The place made into the objective is to provide the epoxy resin composition for sealing which can reduce the deformation | transformation of the wire at the time of compression molding.

  As a result of intensive studies to solve the above problems, the present inventors have evaluated the porosity when the epoxy resin composition is cured under predetermined conditions, thereby improving the meltability of the epoxy resin composition. It has been found that it can be used as an index of viscosity in a low shear region that cannot be measured by a conventional spiral flow or disk flow. And it discovered that said subject could be achieved with the specific epoxy resin composition for sealing which prescribed | regulated this porosity, and completed this invention.

That is, the present invention
It is a powdery sealing epoxy resin composition used for sealing elements by compression molding,
Containing (a) an epoxy resin, (b) a curing agent, (c) an inorganic filler, (d) a curing accelerator, and (e) a coupling agent as essential components,
The epoxy resin composition is accommodated in the aluminum foil container so as to cover the entire surface of the bottom surface of the aluminum foil container having a flat bottom surface, and heated at 175 ° C. under atmospheric pressure for 3 minutes. When the product is cured, the area of the void formed on the surface in contact with the bottom surface of the cured epoxy resin composition is 5. 5% of the total area of the surface in contact with the bottom surface of the cured epoxy resin composition. 8% or more and 30% or less,
Wherein (c) inorganic filler, an average particle diameter _{(D 50)} and is 5μm or more 35μm or less is fused spherical silica (c1), an average particle diameter _{(D 50)} of less than 5μm or more 0.1μm fused spherical silica (c2 ) And
The (d) curing accelerator is a phosphorus atom-containing compound selected from the group consisting of a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, and an adduct of a phosphonium compound and a silane compound. Oh it is,
Content of the said fused spherical silica (c1) is 70 mass% or more and 94 mass% or less on the basis of the said (c) whole inorganic filler,
The content of the fused spherical silica (c2) is 6% by mass or more and 30% by mass or less based on the whole (c) inorganic filler,
The blending ratio of the (a) epoxy resin is 2% by mass or more and 15% by mass or less based on the whole of the epoxy resin composition,
The blending ratio of the (b) curing agent is 0.8% by mass or more and 10% by mass or less based on the whole epoxy resin composition,
The content of the inorganic filler (c) is 50% by mass or more and 95% by mass or less based on the entire epoxy resin composition, and provides an epoxy resin composition for sealing. .

  Moreover, this invention provides the manufacturing method of the electronic device characterized by sealing an element by compression molding using said epoxy resin composition for sealing.

  Moreover, this invention provides the electronic device characterized by sealing an element by compression molding using said epoxy resin composition for sealing.

  According to the present invention, it is possible to provide an epoxy resin composition for sealing that can reduce the deformation of a wire during compression molding, and thus it is possible to improve the reliability of an electronic device having an element sealed using the composition. become.

It is a figure explaining an example of the evaluation method of the epoxy resin composition for sealing of this invention. It is the schematic of an example from conveyance to weighing in the method of sealing a semiconductor element by compression molding using the epoxy resin composition for sealing of this invention, and obtaining a semiconductor device. It is the schematic of an example of the supply method to the lower mold cavity of a metal mold | die in the method of sealing a semiconductor element by compression molding using the epoxy resin composition for sealing of this invention, and obtaining a semiconductor device. It is the figure which showed the cross-sectional structure about an example of the semiconductor device obtained by sealing the semiconductor element mounted in the lead frame using the epoxy resin composition for sealing which concerns on this invention. It is the figure which showed the cross-sectional structure about an example of the semiconductor device obtained by sealing the semiconductor element mounted in the circuit board using the epoxy resin composition for sealing which concerns on this invention. It is a figure which shows an Example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  The present invention is a granular sealing epoxy resin composition used for sealing an element by compression molding. The epoxy resin composition for sealing of the present invention contains (a) an epoxy resin, (b) a curing agent, and (c) an inorganic filler as essential components. The sealing epoxy resin composition of the present invention is placed on a smooth surface, heated and dissolved, and when cured by continuing to heat as it is, the surface of the cured product in contact with the smooth surface Is 40% or less.

Specifically, the porosity of the epoxy resin composition for sealing of the present invention can be measured as follows. FIG. 1 is a diagram for explaining an example of a method for measuring the porosity. First, an aluminum foil container having a flat bottom surface is prepared, and the sealing epoxy resin composition is accommodated in the aluminum foil container so that the entire bottom surface of the aluminum foil container is covered with the sealing epoxy resin composition (FIG. 1 (a)). Next, the entire aluminum foil container containing the sealing epoxy resin composition is heated in an atmosphere of 175 ° C. for 3 minutes while exposing the sealing epoxy resin composition to atmospheric pressure. By doing so, the epoxy resin composition for sealing is cured (FIG. 1B). Then, the cured epoxy resin composition for curing was taken out from the aluminum foil container (FIG. 1 (c)), and the surface of the sealing epoxy resin composition that was in contact with the bottom surface of the aluminum foil container was observed (FIG. 1 (d)), the ratio of the area of the void formed on the observation target surface to the total area of the observation target surface (the surface that was in contact with the bottom surface of the cured sealing epoxy resin composition aluminum foil container), That is, the porosity is obtained.
The porosity of the epoxy resin composition for sealing of the present invention is 40% or less, preferably 30% or less, more preferably 10% or less. The lower the porosity, the better the melting epoxy resin composition can be. However, if the porosity is 0.1% or more, the sealing has sufficient meltability at the time of compression molding. The epoxy resin composition can be used.

  The method for obtaining the area of the gap is not particularly limited. For example, the surface of the cured sealing epoxy resin composition that is in contact with the bottom surface of the aluminum foil container is photographed with a digital camera to form a digital image, and image processing is performed. It may be calculated by binarizing. For example, when the gap is processed into black, the total of the black portions may be set as the area of the gap. The void ratio can be obtained by calculating the ratio of the area of the black portion to the entire area of the imaged observation target surface.

  The shape of the aluminum foil container used for the measurement of the porosity may be any as long as it has a flat bottom surface and can accommodate the epoxy resin composition for sealing. Moreover, the thickness of an aluminum foil container can be 0.01 mm or more and 2 mm or less, for example. As an example of a preferable aspect of the aluminum foil container, the container is left in an oven in which an empty container is maintained at an ambient temperature of 170 ° C. or higher and 180 ° C. or lower, and the surface temperature of the inner surface of the bottom surface of the container (the inner surface of the bottom surface of the container) within 30 seconds. Examples of such a container reach a temperature of 170 ° C. or higher and 180 ° C. or lower.

  Further, when the sealing epoxy resin composition is introduced into the aluminum foil container, the thickness of the sealing epoxy resin composition after the curing treatment (w in FIG. 1B) is 2 mm when the porosity is measured. It is preferable to accommodate the sealing epoxy resin composition in an aluminum foil container so that the thickness is 10 mm or less. Moreover, it is more preferable that the surface (surface exposed from the container) of the epoxy resin composition for sealing is flat.

  Moreover, when heating the epoxy resin composition for sealing, the aluminum foil container that accommodates the epoxy resin composition for sealing can be left without tilting, and the aluminum foil that contains the epoxy resin composition for sealing Although it will not specifically limit if the whole container can be heated to 175 degreeC, For example, the method of heating with a thermostat (oven) is mentioned.

  In the present invention, “powder and granular” refers to particles having an indefinite shape, and includes particles and powders. In the epoxy resin composition for sealing of the present invention, the content of particles of 2 mm or more in the particle size distribution measured by sieving using a JIS standard sieve is preferably 3% by mass or less, more preferably 1% It is below mass%. The content of fine powder having a particle size of less than 106 μm in the particle size distribution measured under the same conditions is preferably 5% by mass or less in the epoxy resin composition for sealing of the present invention, and is 3% by mass or less. It is more preferable.

  The atmospheric pressure generally refers to 1 atmosphere (about 0.1 MPa), but in the present invention, the atmospheric pressure can include a range of 0.01 MPa to 1 MPa.

  The sealing epoxy resin composition of the present invention contains (a) an epoxy resin, (b) a curing agent, and (c) an inorganic filler as essential components as described above, but (d) a curing accelerator, ( e) It may further contain a coupling agent. Hereinafter, each component will be specifically described.

[(A) Epoxy resin]
Examples of (a) epoxy resins are monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule, and the molecular weight and molecular structure thereof are not particularly limited. For example, biphenyl type epoxy resins, Bisphenol type epoxy resins, bisphenol F type epoxy resins, tetramethylbisphenol F type epoxy resins and other bisphenol type epoxy resins, stilbene type epoxy resins, hydroquinone type epoxy resins and other crystalline epoxy resins; cresol novolac type epoxy resins, phenol novolacs Type epoxy resin, novolak type epoxy resin such as naphthol novolak type epoxy resin, phenol aralkyl type epoxy resin containing phenylene skeleton, phenol aralkyl type epoxy resin containing biphenylene skeleton, phenylene bone -Containing naphthol aralkyl epoxy resin, phenol aralkyl epoxy resin such as alkoxynaphthalene skeleton-containing phenol aralkyl epoxy resin; trifunctional methane type epoxy resin, trifunctional epoxy resin such as alkyl-modified triphenol methane type epoxy resin; dicyclopentadiene modified Modified phenol type epoxy resins such as 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 alone or in combination of two or more. You may use it in combination. In addition, it is preferable to use those having a biphenyl skeleton in the molecular structure and an epoxy equivalent of 180 or more.

  Although it does not specifically limit about the lower limit of the compounding ratio of the whole epoxy resin, It is preferable that it is 2 mass% or more in all the resin compositions, and it is more preferable that it is 4 mass% or more. When the lower limit of the blending ratio is within the above range, there is little possibility of causing a decrease in fluidity. Further, the upper limit of the blending ratio of the entire epoxy resin is not particularly limited, but is preferably 15% by mass or less, and more preferably 13% by mass or less in the entire resin composition. When the upper limit of the blending ratio is within the above range, there is little possibility of causing a decrease in solder resistance. In order to improve the meltability, it is desirable to adjust the blending ratio as appropriate according to the type of epoxy resin used.

[(B) Curing agent]
(B) The curing agent is not particularly limited as long as it is cured by reacting with an epoxy resin. For example, a straight chain having 2 to 20 carbon atoms such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, etc. Aliphatic diamine, 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, dicyanodiamide, etc. Amines; Anili Resol type phenol resins such as modified resole resins and dimethyl ether resole resins; Novolak type phenol resins such as phenol novolac resins, cresol novolac resins, tert-butylphenol novolac resins, nonylphenol novolac resins; phenylene skeleton-containing phenol aralkyl resins, biphenylene skeleton-containing phenol aralkyls Phenol aralkyl resins such as resins; phenol resins having a condensed polycyclic structure such as naphthalene skeleton and anthracene skeleton; polyoxystyrenes such as polyparaoxystyrene; hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA), etc. Alicyclic acid anhydride, trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenone tetracarboxylic Acid anhydrides including aromatic acid anhydrides such as acids (BTDA); Polymercaptan compounds such as polysulfides, thioesters and thioethers; Isocyanate compounds such as isocyanate prepolymers and blocked isocyanates; Organics such as carboxylic acid-containing polyester resins Acids are exemplified. These may be used alone or in combination of two or more. Of these, the curing agent used for the semiconductor encapsulating material is preferably a compound having at least two phenolic hydroxyl groups in one molecule from the viewpoint of moisture resistance, reliability, etc., and a phenol novolac resin and cresol novolac. Resins, tert-butylphenol novolak resins, nonylphenol novolak resins, trisphenolmethane novolak resins and other novolak type phenol resins; resol type phenol resins; polyoxystyrenes such as polyparaoxystyrene; Resins and the like are exemplified. In addition, it is preferable to use those having a phenylene and / or biphenyl skeleton in the molecular structure and a hydroxyl group equivalent of 160 or more.

  Although it does not specifically limit about the lower limit of the compounding ratio of the whole hardening | curing agent, It is preferable that it is 0.8 mass% or more in all the resin compositions, and it is more preferable that it is 1.5 mass% or more. When the lower limit value of the blending ratio is within the above range, sufficient fluidity can be obtained. Further, the upper limit of the blending ratio of the entire curing agent is not particularly limited, but is preferably 10% by mass or less, and more preferably 8% by mass or less in the entire resin composition. When the upper limit of the blending ratio is within the above range, good solder resistance can be obtained. In order to improve the meltability, it is desirable to adjust the blending ratio as appropriate according to the type of curing agent used.

  In the case of using a phenol resin curing agent as the curing agent, the blending ratio of the entire epoxy resin and the entire phenol resin curing agent is the number of epoxy groups (EP) of the entire epoxy resin and the entire phenol resin curing agent. The equivalent ratio (EP) / (OH) to the number of phenolic hydroxyl groups (OH) is preferably 0.8 or more and 1.3 or less. When the equivalent ratio is within this range, sufficient curability can be obtained during molding of the resin composition. Moreover, when the equivalent ratio is within this range, good physical properties in the cured resin can be obtained. In consideration of the reduction of warpage in the area surface mount type semiconductor device, the curing accelerator used is used so that the curability of the resin composition and the glass transition temperature or the thermal elastic modulus of the cured resin can be increased. It is desirable to adjust the equivalent ratio (Ep / Ph) between the number of epoxy groups (Ep) of the entire epoxy resin and the number of phenolic hydroxyl groups (Ph) of the entire curing agent according to the kind of the epoxy resin. In order to improve the meltability, it is desirable to adjust the equivalent ratio as appropriate according to the type of epoxy resin and phenol resin curing agent used.

[(C) Inorganic filler]
(C) The inorganic filler is not particularly limited as long as the resin composition of the present invention has good meltability. For example, silica such as fused crushed silica, fused spherical silica, crystalline silica, and secondary agglomerated silica. Alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, silicon carbide, aluminum hydroxide, magnesium hydroxide, titanium white, talc, clay, mica, glass fiber and the like. Among these, fused spherical silica is particularly preferable. Further, the shape of the particles is preferably infinitely spherical, and the amount of filling can be increased by mixing particles having different particle sizes. Moreover, in order to improve the meltability of the resin composition, it is preferable to use fused spherical silica.

(C) the inorganic filler may be mixed with one or more fillers, the entire specific surface area (SSA) is preferable to be below ^{5 m} 2 / g, the lower limit is 0.1 m ² / g or more is preferable, and 2 m ² / g or more is more preferable. Moreover, (c) The average particle diameter (D ₅₀ ) of the entire inorganic filler is preferably 1 μm or more and 30 μm or less, more preferably 2 μm or more and 20 μm or less, and further preferably 5 μm or more and 20 μm or less.

As the inorganic filler, two or more kinds of inorganic fillers having different specific surface areas (SSA) and / or average particle diameters (D ₅₀ ) can be used.

Examples of relatively large inorganic filler average particle diameter _{(D 50),} preferably an average particle size _{(D 50)} 5μm or 35μm or less, or more preferably 30μm or less of spherical silica least 10 [mu] m. The content of such an inorganic filler having a relatively large average particle diameter (D ₅₀ ) is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably, with respect to (c) the entire inorganic filler. It can be 60 mass% or more.

Preferred examples of relatively large inorganic filler average particle size _{(D 50),} an average particle diameter _{(D 50)} is at 5μm or 35μm or less, and the particle diameter that satisfies both of the following (i) to (v) Examples include fused spherical silica (c1) having a distribution.
(I) 1 to 4.5% by mass of particles having a particle size of 1 μm or less (c1) based on the whole fused spherical silica,
(Ii) containing 7% by mass to 11% by mass of particles having a particle size of 2 μm or less,
(Iii) 13 to 17% by mass of particles having a particle size of 3 μm or less,
(Iv) 2% by mass or more and 7% by mass or less of particles having a particle diameter exceeding 48 μm;
(V) Containing 33% by mass or more and 40% by mass or less of particles having a particle diameter of more than 24 μm.
The content of such (c1) fused spherical silica is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 60% by mass or more in the (c) inorganic filler. By doing so, the meltability can be further improved.

As an inorganic filler having a relatively large average particle diameter (D ₅₀ ), the specific surface area is preferably 0.1 m ² / g or more and 5.0 m ² / g or less, more preferably 1.5 m ² / g or more and 5.0 m ^2. / G or less of spherical silica is preferably used. The content of such spherical silica is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 60% by mass or more with respect to (c) the entire inorganic filler.

As examples of average particle diameter _{(D 50)} is relatively small inorganic filler, an average particle diameter _{(D 50)} preferably include 5μm less spherical silica least 0.1 [mu] m. The content of the inorganic filler having a relatively small average particle diameter (D ₅₀ ) is preferably 60% by mass or less, more preferably 45% by mass or less, and still more preferably 30% by mass with respect to the entire inorganic filler. % Or less.

The average particle diameter of Preferred examples of relatively small inorganic filler average particle size _{(D 50),} the average particle diameter _{(D 50)} of less than 5μm or more 0.1μm fused spherical silica (c2), as a more preferred example ( Examples include using fused spherical silica (c3) having a D ₅₀ ) of 0.1 μm or more and 1 μm or less and fused spherical silica (c4) having an average particle diameter (D ₅₀ ) of 1 μm or more and less than 5 μm, either singly or in combination. .

The inorganic filler having a relatively small average particle diameter (D ₅₀ ) has a specific surface area of 3.0 m ² / g or more and 10.0 m ² / g or less, more preferably 3.5 m ² / g or more and 8 m ² / g. The following spherical silica is mentioned. The content of such spherical silica is preferably 80% by mass or less, more preferably 50% by mass or less, and still more preferably 20% by mass or less with respect to (c) the entire inorganic filler.

As a more preferable aspect in the case of combining (c) inorganic fillers having different specific surface areas (SSA) and / or average particle diameters (D ₅₀ ), (c) 70 masses of (c1) fused spherical silica in the inorganic fillers. % To 94% by mass, and (c2) 6% to 30% by mass of fused spherical silica is preferably contained. As a more preferred embodiment, (c) fused spherical silica (c1) containing 70 mass% or more and 94 mass% or less of fused spherical silica and having an average particle size (D ₅₀ ) of 0.1 μm or more and 1 μm or less ( 1 to 29% by mass of c3), and 1 to 29% by mass of fused spherical silica (c4) having an average particle size (D ₅₀ ) of 1 to 5 μm, and (c3) and ( The total amount of c4) may be 6 mass% or more and 30 mass% or less. By carrying out like this, the further outstanding meltability expresses and is preferable.
In addition, in this invention, the specific surface area (SSA) of an inorganic filler means what was calculated | required and measured with the commercially available specific surface area meter (For example, MACSORB HM-MODEL-1201 etc. by Corporation | KK Mountec). Also, an average particle diameter _{(D 50)} and particle size of the inorganic filler is commercially available laser particle size distribution analyzer (e.g., manufactured by Shimadzu Corporation, SALD-7000 etc.) refers to that determined by measuring with.

  (C) As a lower limit of the content rate of an inorganic filler, it is preferable that it is 70 mass% or more on the basis of the whole epoxy resin composition for sealing of this invention, and it is more preferable that it is 75 mass% or more. When the lower limit of the content of the inorganic filler is within the above range, the cured product physical properties of the resin composition do not increase moisture absorption or decrease strength, and have good solder crack resistance. Can be obtained. Moreover, as an upper limit of the content rate of an inorganic filler, it is preferable that it is 95 mass% or less of the whole resin composition, It is more preferable that it is 92 mass% or less, It is especially preferable that it is 90 mass% or less. When the upper limit value of the content ratio of the inorganic filler is within the above range, the flowability is not impaired and good moldability can be obtained. Moreover, it is preferable to set the content of the inorganic filler low within a range in which good solder resistance is obtained.

[(D) Curing accelerator]
(D) As a hardening accelerator, what is necessary is just to accelerate | stimulate the hardening reaction of an epoxy group and a phenolic hydroxyl group, and what is generally used for a sealing material can be used. Specific examples include phosphorus-containing compounds such as organic phosphines, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, adducts of phosphonium compounds and silane compounds; 1,8-diazabicyclo (5 , 4, 0) Undecene-7, amidine compounds such as imidazole, tertiary amines such as benzyldimethylamine, amidinium salts that are quaternary onium salts of the above compounds, and nitrogen atom-containing compounds typified by ammonium salts. It is done. Among these, a phosphorus atom-containing compound is preferable from the viewpoint of curability, and from the viewpoint of balance between fluidity and curability, a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, a phosphonium compound A curing accelerator having a latent property such as an adduct of silane compound is more preferable. In view of fluidity, tetra-substituted phosphonium compounds are particularly preferable. From the viewpoint of solder resistance, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds are particularly preferable, and in view of latent curability. An adduct of a phosphonium compound and a silane compound is particularly preferable. Further, from the viewpoint of continuous moldability, a tetra-substituted phosphonium compound is preferable. In view of cost, organic phosphine and nitrogen atom-containing compounds are also preferably used.

  Examples of the organic phosphine that can be used in the epoxy resin composition according to the present invention include a first phosphine such as ethylphosphine and phenylphosphine; a second phosphine such as dimethylphosphine and diphenylphosphine; trimethylphosphine, triethylphosphine, tributylphosphine, A tertiary phosphine such as triphenylphosphine can be used.

  Examples of the tetra-substituted phosphonium compound that can be used in the epoxy resin composition according to the present invention include compounds represented by the following general formula (1).

  In the general formula (1), P represents a phosphorus atom, R1, R2, R3 and R4 each independently represents an aromatic group or an alkyl group, and A represents a functional group selected from a hydroxyl group, a carboxyl group and a thiol group. Represents an anion of an aromatic organic acid having at least one of the groups in the aromatic ring, and AH is an aromatic organic having at least one functional group selected from a hydroxyl group, a carboxyl group, and a thiol group in the aromatic ring Represents an acid, x and y are integers of 1 to 3, z is an integer of 0 to 3, and x = y.

  Although the compound represented by General formula (1) is obtained as follows, for example, it is not limited to this. First, a tetra-substituted phosphonium halide, an aromatic organic acid and a base are mixed in an organic solvent and mixed uniformly to generate an aromatic organic acid anion in the solution system. Next, when water is added, the compound represented by the general formula (1) can be precipitated. In the compound represented by the general formula (1), R1, R2, R3, and R4 bonded to the phosphorus atom are phenyl groups, and AH is bonded to the phosphorus atom from the viewpoint of excellent balance between the yield during synthesis and the curing acceleration effect. A compound having a hydroxyl group in an aromatic ring, that is, a phenol compound, and A is preferably an anion of the phenol compound. The phenol compounds are monocyclic phenol, cresol, catechol, resorcin, condensed polycyclic naphthol, dihydroxynaphthalene, (polycyclic) bisphenol A, bisphenol F, bisphenol S, biphenol having a plurality of aromatic rings. , Phenylphenol, phenol novolac and the like, and among them, phenol compounds having two hydroxyl groups are preferably used.

  Examples of the phosphobetaine compound that can be used in the epoxy resin composition according to the present invention include compounds represented by the following general formula (2).

  In General formula (2), X1 represents a C1-C3 alkyl group, Y1 represents a hydroxyl group, a is an integer of 0-5, b is an integer of 0-4.

  The compound represented by the general formula (2) is obtained, for example, as follows. First, it is obtained through a step of bringing a triaromatic substituted phosphine, which is a third phosphine, into contact with a diazonium salt and replacing the triaromatic substituted phosphine with a diazonium group of the diazonium salt. However, the present invention is not limited to this.

  Examples of the adduct of a phosphine compound and a quinone compound that can be used in the epoxy resin composition according to the present invention include compounds represented by the following general formula (3).

  In General formula (3), P represents a phosphorus atom, R5, R6, and R7 represent a C1-C12 alkyl group or a C6-C12 aryl group mutually independently, R8, R9, and R10 independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R8 and R9 may be bonded to each other to form a ring.

  Examples of the phosphine compound used as an adduct of a phosphine compound and a quinone compound include an aromatic ring such as triphenylphosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) phosphine, trinaphthylphosphine, and tris (benzyl) phosphine. Those having a substituent such as a substituent or an alkyl group or an alkoxyl group are preferred, and examples of the substituent such as an alkyl group and an alkoxyl group include those having 1 to 6 carbon atoms. From the viewpoint of availability, triphenylphosphine is preferable.

  In addition, examples of the quinone compound used for the adduct of the phosphine compound and the quinone compound include o-benzoquinone, p-benzoquinone, and anthraquinones. Among them, p-benzoquinone is preferable from the viewpoint of storage stability.

  As a method for producing an adduct of a phosphine compound and a quinone compound, the adduct can be obtained by contacting and mixing in a solvent capable of dissolving both organic tertiary phosphine and benzoquinone. The solvent is preferably a ketone such as acetone or methyl ethyl ketone, which has low solubility in the adduct. However, the present invention is not limited to this.

  In the compound represented by the general formula (3), R5, R6 and R7 bonded to the phosphorus atom are phenyl groups, and R8, R9 and R10 are hydrogen atoms, that is, 1,4-benzoquinone and triphenyl The compound to which phosphine is added is preferable in that it reduces the thermal elastic modulus of the cured epoxy resin composition.

  Examples of the adduct of a phosphonium compound and a silane compound that can be used in the epoxy resin composition according to the present invention include compounds represented by the following formula (4).

  In General formula (4), P represents a phosphorus atom and Si represents a silicon atom. R11, R12, R13 and R14 each independently represent an organic group having an aromatic ring or a heterocyclic ring, or an aliphatic group, and X2 is an organic group bonded to the groups Y2 and Y3. X3 is an organic group bonded to the groups Y4 and Y5. Y2 and Y3 represent a group formed by releasing a proton from a proton donating group, and groups Y2 and Y3 in the same molecule are bonded to a silicon atom to form a chelate structure. Y4 and Y5 represent a group formed by releasing a proton from a proton donating group, and groups Y4 and Y5 in the same molecule are bonded to a silicon atom to form a chelate structure. X2 and X3 may be the same or different from each other, and Y2, Y3, Y4, and Y5 may be the same or different from each other. Z1 is an organic group having an aromatic ring or a heterocyclic ring, or an aliphatic group.

  In the general formula (4), examples of R11, R12, R13, and R14 include phenyl group, methylphenyl group, methoxyphenyl group, hydroxyphenyl group, naphthyl group, hydroxynaphthyl group, benzyl group, methyl group, ethyl group, n-butyl group, n-octyl group, cyclohexyl group, and the like. Among these, an aromatic group having a substituent such as phenyl group, methylphenyl group, methoxyphenyl group, hydroxyphenyl group, hydroxynaphthyl group, or the like. A substituted aromatic group is more preferred.

  Moreover, in General formula (4), X2 is an organic group couple | bonded with Y2 and Y3. Similarly, X3 is an organic group bonded to the groups Y4 and Y5. Y2 and Y3 are groups formed by proton-donating groups releasing protons, and groups Y2 and Y3 in the same molecule are combined with a silicon atom to form a chelate structure. Similarly, Y4 and Y5 are groups formed by proton-donating groups releasing protons, and groups Y4 and Y5 in the same molecule are combined with a silicon atom to form a chelate structure. The groups X2 and X3 may be the same or different from each other, and the groups Y2, Y3, Y4, and Y5 may be the same or different from each other. The groups represented by -Y2-X2-Y3- and -Y4-X3-Y5- in general formula (4) are composed of groups in which a proton donor releases two protons. The proton donor is preferably an organic acid having at least two carboxyl groups or hydroxyl groups in the molecule, and further an aromatic group having at least two carboxyl groups or hydroxyl groups on the carbon constituting the aromatic ring. A compound is preferable, and an aromatic compound having at least two hydroxyl groups on adjacent carbons constituting an aromatic ring is more preferable. For example, catechol, pyrogallol, 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,2′-biphenol, 1,1′-bi-2-naphthol, salicylic acid, 1-hydroxy-2-naphthoic acid, 3 -Hydroxy-2-naphthoic acid, chloranilic acid, tannic acid, 2-hydroxybenzyl alcohol, 1,2-cyclohexanediol, 1,2-propanediol, glycerin and the like. Among these, catechol, 1,2-dihydroxynaphthalene, and 2,3-dihydroxynaphthalene are more preferable from the viewpoint of easy availability of raw materials and a curing acceleration effect.

  Z1 in the general formula (4) represents an organic group or an aliphatic group having an aromatic ring or a heterocyclic ring. Specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group. Reactions such as aliphatic hydrocarbon groups such as octyl group and aromatic hydrocarbon groups such as phenyl group, benzyl group, naphthyl group and biphenyl group, glycidyloxypropyl group, mercaptopropyl group, aminopropyl group and vinyl group Among them, a methyl group, an ethyl group, a phenyl group, a naphthyl group, and a biphenyl group are more preferable from the viewpoint of thermal stability.

  As a method for producing an adduct of a phosphonium compound and a silane compound, a silane compound such as phenyltrimethoxysilane and a proton donor such as 2,3-dihydroxynaphthalene are added to a flask containing methanol and dissolved, and then room temperature. Sodium methoxide-methanol solution is added dropwise with stirring. Furthermore, when a solution prepared by dissolving a tetra-substituted phosphonium halide such as tetraphenylphosphonium bromide in methanol in methanol is added dropwise with stirring at room temperature, crystals are precipitated. The precipitated crystals are filtered, washed with water, and vacuum dried to obtain an adduct of a phosphonium compound and a silane compound. However, it is not limited to this.

  The lower limit of the blending ratio of the entire curing accelerator is preferably 0.1% by mass or more in the total resin composition. Sufficient curability can be obtained when the lower limit of the blending ratio of the entire curing accelerator is within the above range. Moreover, it is preferable that the upper limit of the mixture ratio of the whole hardening accelerator is 1 mass% or less in all the resin compositions. Sufficient fluidity can be obtained when the upper limit of the blending ratio of the entire curing accelerator is within the above range. In order to improve the meltability, it is desirable to adjust the blending ratio as appropriate according to the type of curing accelerator used.

[(E) Coupling agent]
(E) As coupling agents, various known silane compounds such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, vinyl silane, titanium compounds, aluminum chelates, aluminum / zirconium compounds, etc. An agent can be used. Examples of these include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxy. Silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane 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- (dimethoxymethylsilylisopropyl) ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, γ-chloro Propyl trimeth Sisilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-triethoxylyl-N- (1,3-dimethyl) Silane coupling agents such as hydrolyzate of rubylidene) propylamine, isopropyltriisostearoyl titanate, isopropyltris (dioctylpyrophosphate) titanate, isopropyltri (N-aminoethyl-aminoethyl) titanate, tetraoctylbis ( Ditridecyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxy Siacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tric Examples include titanate coupling agents such as milphenyl titanate and tetraisopropyl bis (dioctyl phosphite) titanate, and these may be used alone or in combination of two or more.

  (E) The blending amount of the coupling agent is preferably 0.05% by mass or more and 3% by mass or less, and more preferably 0.1% by mass or more and 2.5% by mass or less with respect to (c) the inorganic filler. . By setting it as 0.05 mass% or more, a flame | frame can be adhere | attached favorably, and a moldability can be improved by setting it as 3 mass% or less.

  In the epoxy resin composition of the present invention, in addition to the above components, if necessary, a colorant such as carbon black; a release agent such as natural wax, synthetic wax, higher fatty acid or metal salt thereof, paraffin, oxidized polyethylene, etc. A low stress agent such as silicone oil and silicone rubber; an ion scavenger such as hydrotalcite; a flame retardant such as aluminum hydroxide; and various additives such as an antioxidant.

  The epoxy resin composition of the present invention can be made into a granular form by mixing and kneading the above components, and then using various methods such as pulverization, granulation, extrusion cutting, and sieving alone or in combination. For example, after each raw material component is premixed by a mixer, heated and kneaded by a kneader such as a roll, a kneader, or an extruder, the inside of a rotor composed of a cylindrical outer peripheral portion having a plurality of small holes and a disk-shaped bottom surface In addition, a method in which a melt-kneaded resin composition is supplied and the resin composition is obtained by passing through small holes by centrifugal force obtained by rotating a rotor (hereinafter also referred to as “centrifugal milling”). A method of obtaining a pulverized product after kneading, cooling, and pulverizing steps as described above, by removing coarse particles and fine particles using a sieve (hereinafter, also referred to as “pulverization sieving method”). ; After premixing each raw material component with a mixer, using an extruder equipped with a die having a plurality of small diameters at the tip of the screw, the mixture is heated and kneaded and extruded into a strand from the small holes arranged in the die. Slide the molten resin almost parallel to the die surface. Methods that may be cut by rotating cutter (hereinafter, also referred to as "hot cut method".), And the like. In any method, the particle size distribution and bulk density of the present invention can be obtained by selecting kneading conditions, centrifugal conditions, sieving conditions, cutting conditions, and the like. A particularly preferable production method is centrifugal milling, and the powdery epoxy resin composition obtained thereby can stably express the particle size distribution and bulk density of the present invention. Preferred for preventing sticking. In addition, in the centrifugal milling method, the particle surface can be smoothed to some extent, so that the particles are not caught and the frictional resistance with the surface of the conveying path does not increase, and the bridge ( This is also preferable for prevention of clogging) and prevention of retention on the conveyance path. Further, the centrifugal milling method is advantageous in terms of transportability in compression molding because the particles are formed using a centrifugal force from a molten state, so that the voids are included in the particles to some extent and the bulk density can be lowered to some extent.

  On the other hand, in the pulverization sieving method, it is necessary to examine a method for treating a large amount of fine powder and coarse particles generated by sieving, but the sieving equipment is used in the existing production line for epoxy resin compositions. Therefore, it is preferable in that a conventional production line can be used as it is. The pulverization sieving method expresses the particle size distribution of the present invention, such as selection of sheet thickness when forming a molten resin sheet before pulverization, selection of pulverization conditions and screen during pulverization, selection of sieving during sieving, etc. Therefore, since there are many factors that can be controlled independently, it is preferable in that there are many choices of means for adjusting to a desired particle size distribution. The hot cut method is also preferable in that a conventional production line can be used as it is, for example, by adding a hot cut mechanism to the tip of the extruder. As a centrifugal milling method which is an example of a production method for obtaining the powdery epoxy resin composition for sealing of the present invention, for example, there is a method described in JP 2010-159400 A.

  Next, the semiconductor device of the present invention formed by sealing a semiconductor element by compression molding using the epoxy resin composition of the present invention will be described. First, a method for obtaining a semiconductor device by sealing a semiconductor element by compression molding using the epoxy resin composition of the present invention will be described. The conceptual diagram of the weighing method of the epoxy resin composition of this invention and the supply method to a mold cavity is shown to FIG. The powdered epoxy resin composition is instantaneously supplied into the lower mold cavity 104 by using a conveying means such as a vibration feeder 101 on a resin material supply container 102 having a resin material supply mechanism such as a shutter. A certain amount of the granular resin composition 103 is conveyed to prepare a resin material supply container 102 in which the granular resin composition 103 is placed (see FIG. 2). At this time, the measurement of the powdery resin composition 103 in the resin material supply container 102 can be performed by a measuring means installed under the resin material supply container 102. Next, between the upper mold and the lower mold of the compression molding mold, the resin material supply container 102 in which the granular resin composition 103 is placed is installed, and a lead frame or a circuit board on which a semiconductor element is mounted is mounted. It is fixed to the upper mold of the compression molding die by a fixing means such as clamp and suction (not shown) so that the semiconductor element mounting surface is on the lower side. In the case of a structure having a part through which the lead frame or the circuit board penetrates, the surface opposite to the semiconductor element mounting surface is backed by using a film or the like.

  Next, when the weighed powder resin composition 103 is supplied into the lower mold cavity 104 by a resin material supply mechanism such as a shutter constituting the bottom surface of the resin material supply container 102 (see FIG. 3), it is powdery. The resin composition 103 is melted at a predetermined temperature in the lower mold cavity 104. Furthermore, after carrying out the resin material supply container 102 out of the mold, the mold is clamped by a compression molding machine while reducing the pressure inside the cavity as necessary so that the molten resin composition surrounds the semiconductor element. The semiconductor element is encapsulated by filling the cavity and further curing the resin composition for a predetermined time. After a predetermined time has elapsed, the mold is opened and the semiconductor device is taken out. It is not essential to perform deaeration molding under reduced pressure in the cavity, but it is preferable because voids in the cured product of the resin composition can be reduced. Further, the semiconductor element mounted on the lead frame or the circuit board may be plural, and may be stacked or mounted in parallel.

  The semiconductor element sealed with the semiconductor device of the present invention is not particularly limited, and examples thereof include an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and a solid-state imaging element.

  The form of the semiconductor device of the present invention is not particularly limited, and examples thereof include a ball grid array (BGA) and a MAP type BGA. Also applicable to chip size package (CSP), quad flat non-ready package (QFN), small outline non-ready package (SON), lead frame BGA (LF-BGA), etc. .

  The semiconductor device of the present invention in which the semiconductor element is encapsulated with the cured resin composition by compression molding is completely cured as it is or at a temperature of about 80 ° C. to 200 ° C. for about 10 minutes to 10 hours. Later, it is mounted on an electronic device or the like.

  Below, a lead frame or a circuit board, one or more semiconductor elements stacked or mounted in parallel on the lead frame or the circuit board, and bonding wires for electrically connecting the lead frame or the circuit board and the semiconductor element A semiconductor device including a semiconductor element and a sealing material for sealing a bonding wire will be described in detail with reference to the drawings, but the present invention is not limited to the one using a bonding wire.

  FIG. 4 is a view showing a cross-sectional structure of an example of a semiconductor device obtained by sealing a semiconductor element mounted on a lead frame using the epoxy resin composition according to the present invention. A semiconductor element 401 is fixed on the die pad 403 through a die bond material cured body 402. The electrode pad of the semiconductor element 401 and the lead frame 405 are connected by a wire 404. The semiconductor element 401 is sealed with a sealing material 406 made of a cured product of the epoxy resin composition of the present invention.

  FIG. 5 is a view showing a cross-sectional structure of an example of a semiconductor device obtained by sealing a semiconductor element mounted on a circuit board using the epoxy resin composition according to the present invention. A semiconductor element 401 is fixed on a circuit board 408 through a die bond material cured body 402. The electrode pad of the semiconductor element 401 and the electrode pad on the circuit board 408 are connected by a wire 404. Only one side of the circuit board 408 on which the semiconductor element 401 is mounted is sealed with a sealing material 406 made of a cured product of the epoxy resin composition of the present invention. The electrode pad 407 on the circuit board 408 is bonded to the solder ball 409 on the non-sealing surface side on the circuit board 408 inside.

  The epoxy resin composition of the present invention is not limited to semiconductor elements such as integrated circuits and large-scale integrated circuits, but includes various elements such as transistors, thyristors, diodes, solid-state imaging elements, capacitors, resistors, and LEDs. It can be sealed.

As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.
Hereinafter, examples of the reference form will be added.
1. It is a powdery sealing epoxy resin composition used for sealing elements by compression molding,
Including (a) an epoxy resin, (b) a curing agent, and (c) an inorganic filler as essential components,
The epoxy resin composition is accommodated in the aluminum foil container so as to cover the entire surface of the bottom surface of the aluminum foil container having a flat bottom surface, and heated at 175 ° C. under atmospheric pressure for 3 minutes. When the product is cured, the area of the void formed on the surface contacting the bottom surface of the cured epoxy resin composition is 40% of the total area of the surface contacting the bottom surface of the cured epoxy resin composition An epoxy resin composition for sealing, comprising:
2. (C) The inorganic filler has a specific surface area (SSA) of 5 m ² / g or less; The epoxy resin composition for sealing as described in 2.
3. (C) The average particle diameter (D ₅₀ ) of the inorganic filler is 1 μm or more and 30 μm or less. Or 2. The epoxy resin composition for sealing as described in 2.
4). The inorganic filler (c) has an average particle diameter (D ₅₀ ) of 5 μm or more and 35 μm or less, and fused spherical silica (c1) having a particle size distribution satisfying any of the following (i) to (v): And (c1) the content of fused spherical silica is 10% by mass or more based on the total amount of (c) inorganic filler. To 3. The epoxy resin composition for sealing according to any one of the above.
(I) 1 to 4.5% by mass of particles having a particle size of 1 μm or less,
(Ii) containing 7% by mass to 11% by mass of particles having a particle size of 2 μm or less,
(Iii) 13 to 17% by mass of particles having a particle size of 3 μm or less,
(Iv) 2% by mass or more and 7% by mass or less of particles having a particle diameter exceeding 48 μm;
(V) Containing 33% by mass or more and 40% by mass or less of particles having a particle diameter of more than 24 μm.
5. The (c) inorganic filler includes an inorganic filler (c2) having an average particle diameter (D ₅₀ ) of 0.1 μm or more and less than 5 μm,
The content of (c1) fused spherical silica is 70% by mass or more and 94% by mass or less based on (c) the whole inorganic filler,
(C2) The content of the inorganic filler is 6% by mass or more and 30% by mass or less based on (c) the entire inorganic filler. The epoxy resin composition for sealing as described in 2.
6). The content of the (c) inorganic filler is 50% by mass or more and 95% by mass or less based on the entire epoxy resin composition. To 5. The epoxy resin composition for sealing according to any one of the above.
7). In the particle size distribution measured by sieving using a JIS standard sieve, the content of particles of 2 mm or more is 3% by mass or less in the epoxy resin composition, and the content of fine powder having a particle size of less than 106 μm is 1. 5 mass% or less in the epoxy resin composition. To 6. The epoxy resin composition for sealing according to any one of the above.
8). (D) a curing accelerator is further included, and the (d) curing accelerator includes a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, and an adduct of a phosphonium compound and a silane compound. 1. a phosphorus atom-containing compound selected from the group To 7. The epoxy resin composition for sealing according to any one of the above.
9. (E) A coupling agent is further included, and the coupling agent is a silane coupling agent having a secondary amino group. To 8. The epoxy resin composition for sealing according to any one of the above.
10. The element is a semiconductor element; Thru 9. The epoxy resin composition for sealing according to any one of the above.
11.1. To 10. A method for manufacturing an electronic device, wherein an element is sealed by compression molding using the sealing epoxy resin composition according to any one of the above.
12.1. To 10. An electronic device obtained by sealing an element by compression molding using the sealing epoxy resin composition according to any one of the above.

It shows below about the component used by the Example and the comparative example.
(Epoxy resin)
Epoxy resin 1: bi-phenylene skeleton containing phenol aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd. NC3000)
Epoxy resin 2: biphenyl type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., YX4000H)

(Phenolic resin)
Phenol resin 1: Biphenylene skeleton-containing phenol aralkyl resin (Maywa Kasei Co., Ltd., MEH-7851SS)
Phenol resin 2: Phenol aralkyl resin containing phenylene skeleton (Mitsui Chemicals, XLC-4L)

(Inorganic filler)
Spherical inorganic filler 1: spherical fused silica (average particle size 16 μm, specific surface area 2.1 m ² / g)
Spherical inorganic filler 2: Spherical fused silica (average particle size 10 μm, specific surface area 4.7 m ² / g)
Spherical inorganic filler 3: spherical fused silica (average particle size 32 μm, specific surface area 1.5 m ² / g)

  Table 1 shows the particle size distribution in the spherical inorganic fillers 1 to 3.

Fine spherical inorganic filler 1: spherical fused silica (average particle size 0.5 μm, specific surface area 6.1 m ² / g)
Fine spherical inorganic filler 2: spherical fused silica (average particle size 1.5 μm, specific surface area 4.0 m ² / g)

(Other ingredients)
Curing accelerator 1: Triphenylphosphine coupling agent: γ-glycidoxypropyltrimethoxysilane carbon black wax: carnauba wax

Example 1-3, Comparative Examples 1 and 2
After the raw materials of the epoxy resin composition having the composition shown in Table 2 were pulverized and mixed for 5 minutes by a super mixer, this mixed raw material was screw rotated at 30 RPM at 100 ° C. in a co-rotating twin screw extruder having a cylinder inner diameter of 65 mm. Next, the resin composition melt-kneaded from above the rotor having a diameter of 20 cm is supplied at a rate of 2 kg / hr by the centrifugal force obtained by rotating the rotor at 3000 RPM. A granular epoxy resin composition for sealing was obtained by passing a plurality of small holes (hole diameter 2.5 mm) in the cylindrical outer peripheral portion heated to 115 ° C. The properties of the resin composition are shown in Table 2.

Example 4
After the raw materials of the epoxy resin composition having the composition shown in Table 2 were pulverized and mixed for 5 minutes by a super mixer, this mixed raw material was screw rotated at 30 RPM at 100 ° C. in a co-rotating twin screw extruder having a cylinder inner diameter of 65 mm. The mixture was melt-kneaded at the resin temperature, cooled and pulverized to obtain a pulverized product, and coarse particles and fine particles were removed using a sieve to obtain a powdery epoxy resin composition for sealing. The properties of the resin composition are shown in Table 2.

<Evaluation method>
The granular epoxy resin compositions in Examples and Comparative Examples were evaluated by the following methods.
1. Porosity Powdery epoxy resin compositions (7 g) of Examples and Comparative Examples were added to an aluminum cup (diameter 50 mm, outer peripheral height 10 mm, thickness 70 μm), and heated in an oven set at 175 ° C. for 3 minutes. The thickness of the epoxy resin composition after curing was 5.2 mm. The cured resin composition was taken out from the aluminum cup, and the surface of the resin composition that was in contact with the bottom surface of the aluminum cup was photographed with a digital camera and imaged. The obtained image was binarized, and the void area (A1) in the plane of the resin composition in contact with the bottom surface of the aluminum cup and the total area (A2) of the surface of the resin composition in contact with the bottom surface of the aluminum cup. Was measured, and the porosity was calculated as shown in Equation (1).
Porosity [%] = (A1 / A2) × 100 (1)

  The digital image and binarized image of Example 1 are shown in FIG. FIG. 6A is a digital image, and FIG. 6B is a binarized image.

2. Specific surface area (SSA)
MACSORB HM-MODEL-1201 manufactured by Mountec Co., Ltd. was used and evaluated by the BET flow method.

3. Average particle size (D ₅₀ )
SALD-7000 manufactured by Shimadzu Corporation was used and evaluated by a laser diffraction particle size distribution measurement method.

4). Disc flow 200 mm (W) x 200 mm (D) x 25 mm (H) upper mold and 200 mm (W) x 200 mm (D) x 15 mm (H) lower mold A flat plate mold for measuring disk flow is used. Put 5 g of the sealing epoxy resin molding material weighed on the upper pan balance on the center of the lower mold heated to 180 ° C., and after 5 seconds, close the upper mold heated to 180 ° C., load 78 N, and cure Compression molding was performed for 90 seconds, and the major axis (mm) and minor axis (mm) of the molded product were measured with a caliper, and the average value (mm) was defined as a disc flow.

5. Wire deformation On a circuit board with a thickness of 0.5 mm, a width of 50 mm, and a length of 210 mm, a semiconductor element with a thickness of 0.3 mm and a square of 9 mm is bonded with silver paste, and a gold wire wire with a width of 25 μm and a length of about 5 mm is pitched What was joined to the semiconductor element and the circuit board at an interval of 60 μm was collectively sealed with a compression molding machine (PMA1040, manufactured by TOWA Corporation) to obtain a MAP molded product. The molding conditions at this time were a mold temperature of 175 ° C., a molding pressure of 3.9 MPa, and a curing time of 120 seconds. Next, the obtained MAP molded product was separated into pieces by dicing to obtain a simulated semiconductor device. Using the soft X-ray apparatus (PRO-TEST-100, manufactured by Softex Co., Ltd.), the wire flow rate in the obtained simulated semiconductor device is the length of the four longest gold wires (length: 5 mm) on the diagonal of the package. The average flow rate was measured, and the wire flow rate (wire flow rate / wire length × 100 (%)) was calculated.

The evaluation results are shown in Table 2.
In the semiconductor device in which the semiconductor element was sealed by compression molding using the epoxy resin composition of the example, the wire deformation was extremely small, whereas when the epoxy resin composition of the comparative example was used, the wire deformation was The result was large.
Moreover, although the powdery epoxy resin compositions of Examples and Comparative Examples were evaluated by spiral flow and disc flow, respectively, those having a long spiral flow and disc flow did not necessarily result in a small porosity. . Therefore, it was found that the evaluation using the porosity is an index of the relationship with the meltability reflecting the viscosity in the low shear region, and cannot be grasped by the evaluation of the fluidity by the spiral flow or the disk flow.

101 Vibration Feeder 102 Resin Material Supply Container 103 Epoxy Resin Composition 104 Lower Mold Cavity 105 Hydroxyl Equivalent 401 Semiconductor Element 402 Die Bond Material Cured Body 403 Die Pad 404 Wire 405 Lead Frame 406 Sealing Material 407 Electrode Pad 408 Circuit Board 409 Solder Ball

Claims (9)

It is a powdery sealing epoxy resin composition used for sealing elements by compression molding,
Containing (a) an epoxy resin, (b) a curing agent, (c) an inorganic filler, (d) a curing accelerator, and (e) a coupling agent as essential components,
The epoxy resin composition is accommodated in the aluminum foil container so as to cover the entire surface of the bottom surface of the aluminum foil container having a flat bottom surface, and heated at 175 ° C. under atmospheric pressure for 3 minutes. When the product is cured, the area of the void formed on the surface in contact with the bottom surface of the cured epoxy resin composition is 5. 5% of the total area of the surface in contact with the bottom surface of the cured epoxy resin composition. 8% or more and 30% or less,
Wherein (c) inorganic filler, an average particle diameter _{(D 50)} and is 5μm or more 35μm or less is fused spherical silica (c1), an average particle diameter _{(D 50)} of less than 5μm or more 0.1μm fused spherical silica (c2 ) And
The (d) curing accelerator is a phosphorus atom-containing compound selected from the group consisting of a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, and an adduct of a phosphonium compound and a silane compound. Oh it is,
Content of the said fused spherical silica (c1) is 70 mass% or more and 94 mass% or less on the basis of the said (c) whole inorganic filler,
The content of the fused spherical silica (c2) is 6% by mass or more and 30% by mass or less based on the whole (c) inorganic filler,
The blending ratio of the (a) epoxy resin is 2% by mass or more and 15% by mass or less based on the whole of the epoxy resin composition,
The blending ratio of the (b) curing agent is 0.8% by mass or more and 10% by mass or less based on the whole epoxy resin composition,
An epoxy resin composition for sealing, wherein the content of the (c) inorganic filler is 50% by mass or more and 95% by mass or less based on the entire epoxy resin composition. The epoxy resin composition for sealing according to claim 1, wherein the specific surface area (SSA) of the (c) inorganic filler is 5 m ² / g or less. The epoxy resin composition for sealing according to claim 1 or 2, wherein the average particle size (D ₅₀ ) of the (c) inorganic filler is 1 µm or more and 30 µm or less. The specific surface area of the spherical fused silica (c1) (SSA) is not more than 0.1 m ² / g or more 5.0 m ² / g, for sealing epoxy resin composition according to any one of claims 1 to 3 . The epoxy resin composition for sealing according to any one of claims 1 to 4 , wherein the fused spherical silica (c2) has a specific surface area (SSA) of 3.0 m ² / g or more and 10.0 m ² / g or less. . In the particle size distribution measured by sieving using a JIS standard sieve, the content of particles having a particle size of 2 mm or more is 3% by mass or less in the epoxy resin composition, and the content of fine powder having a particle size of less than 106 μm is present. The epoxy resin composition for sealing according to any one of claims 1 to 5 , which is 5% by mass or less in the epoxy resin composition. The epoxy resin composition for sealing according to any one of claims 1 to 6 , wherein the (e) coupling agent is a silane coupling agent having a secondary amino group. The epoxy resin composition for sealing according to any one of claims 1 to 7 , wherein the element is a semiconductor element. A method for manufacturing an electronic device, comprising sealing an element by compression molding using the epoxy resin composition for sealing according to any one of claims 1 to 8 .

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