JP2006036915A - Resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition which has a high content of a silica filler having a small particle size, is high in fluidity, and is excellent in heat resistance and moisture resistance. <P>SOLUTION: The resin composition comprises a spherical silica particle having an average particle size of 0.1 μm or more and 5 μm or less and sphericity of 0.8 or more, a silica nano-particle having an average particle size of 1 nm or more and 50 nm or less, and one or more resins selected from a heat- or light-curable resin and a thermoplastic resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin composition used for sealing electronic parts and the like.

As electronic devices have higher performance, higher functionality, and smaller and lighter weight, the form of semiconductor packages to be mounted is becoming more highly integrated, smaller, and thinner. For practical use of such a semiconductor package, development of a sealing material is indispensable together with development of an IC chip. The sealing material is required to have adhesiveness, heat resistance, moisture resistance and the like in order to ensure various reliability of the semiconductor element. At present, a thermosetting resin such as an epoxy resin is often used as a sealing material. A resin composition in which a silica filler is blended with an epoxy resin serving as a matrix has also been developed (see, for example, Patent Document 1).
JP 2000-063630 A

  For example, in flip chip mounting, a liquid sealing material (underfill material) is filled in a gap between the IC chip and the substrate. That is, it is necessary to allow the sealing material to enter a very small gap. Therefore, high fluidity is required for the sealing material. On the other hand, in order to reduce the thermal expansion coefficient and moisture absorption rate of the sealing material and improve heat resistance and moisture absorption resistance, it is desirable to add as much filler as possible to the resin. However, when the blending amount of the filler is increased, the fluidity is lowered. Further, with the recent narrow pitch, it is required to further reduce the particle size of the filler in the sealing material. When the particle size of the filler is reduced, it is difficult to mix the resin with a high density. For example, the maximum amount of silica filler described in Patent Document 1 is 80% by weight. Thus, at present, it is difficult to mix a filler having a small particle diameter in a resin at a high density.

  The present invention has been made in view of such a situation, and provides a resin composition having high fluidity and excellent heat resistance and moisture absorption resistance by incorporating a silica filler having a small particle diameter at a high blending ratio. The task is to do.

  The resin composition of the present invention is cured by heat or light with spherical silica particles having an average particle size of 0.1 μm to 5 μm and a sphericity of 0.8 or more, silica nanoparticles having an average particle size of 1 nm to 50 nm, and heat or light. And one or more resins selected from a curable resin and a thermoplastic resin.

In the resin composition of the present invention, at least two types of silica (SiO ₂ ) fillers having different average particle sizes are mixed and blended. One of them, the spherical silica particles, has a substantially spherical shape with a sphericity of 0.8 or more. In this specification, “sphericity” is defined as “ratio of minimum diameter to maximum diameter of particle”. For example, the ratio of the minimum diameter to the maximum diameter observed as a result of observation with a scanning electron microscope (SEM) may be 0.8 or more.

  Thus, by mixing silica nanoparticles having an average particle size of 1 nm or more and 50 nm or less into spherical silica particles having an approximately true spherical particle shape and an average particle size of 0.1 μm or more and 5 μm or less, the particle size is small in the resin. Silica filler can be dispersed at a high blending ratio. This is presumably because the closest packed state of the silica filler is formed in the resin due to the difference in the particle shape of the spherical silica particles and the particle diameter of the spherical silica particles and the silica nanoparticles. Moreover, the viscosity of a resin composition can be restrained low by mix | blending the spherical silica particle with a substantially spherical shape. Therefore, the resin composition of this invention can mix | blend the silica filler with a small particle diameter with a high compounding ratio, has high fluidity | liquidity, and is excellent in heat resistance and moisture absorption resistance.

  According to the resin composition of the present invention, a silica filler having a small particle diameter can be blended in the resin at a high blending ratio. For this reason, the resin composition of this invention is suitable as a sealing material which seals the clearance gap between an IC chip and a board | substrate.

  Hereinafter, embodiments of the resin composition of the present invention will be described in detail. In addition, the resin composition of the present invention is not limited to the following embodiments, and may be implemented in various forms that have been modified or improved by those skilled in the art without departing from the scope of the present invention. be able to.

<Spherical silica particles>
The average particle diameter of the spherical silica particles constituting the resin composition of the present invention is 0.1 μm or more and 5 μm or less. From the viewpoint of making the particle diameter of the filler to be blended as small as possible, the average particle diameter of the spherical silica particles is preferably 3 μm or less. The sphericity of the spherical silica particles is 0.8 or more. From the viewpoint of improving the fluidity of the resin composition of the present invention and the dispersibility in the resin, and making the silica filler closer to the closest packing state, the sphericity is preferably 0.9 or more. When the spherical silica particles are blended in the resin described later, only one kind of spherical silica particle powder having an average particle diameter in the above range and a sphericity of 0.8 or more may be blended, or two kinds. You may mix and mix the above. If necessary, it is desirable to remove coarse particles of 5 μm or more, 3 μm or more.

  The method for producing the spherical silica particles is not particularly limited. For example, it is desirable to produce silicon particles by burning them by a VMC (Vap-erized Metal Combustion) method. In the VMC method, a chemical flame is formed by a burner in an oxygen-containing atmosphere, and metal powder that constitutes part of the target oxide particles is introduced into the chemical flame in such an amount that a dust cloud is formed. In this method, deflagration is caused to obtain oxide particles.

The operation of the VMC method will be described as follows. First, a gas containing oxygen, which is a reaction gas, is filled in a container to form a chemical flame in the reaction gas. Next, metal powder is introduced into the chemical flame to form a dust cloud with a high concentration (500 g / m ³ or more). Then, thermal energy is given to the metal powder surface by the chemical flame, the surface temperature of the metal powder rises, and metal vapor spreads from the metal powder surface to the surroundings. This metal vapor reacts with oxygen gas to ignite and produce a flame. The heat generated by the flame further promotes the vaporization of the metal powder, and the generated metal vapor and the reaction gas are mixed and propagated in a chain. At this time, the metal powder itself is destroyed and scattered, which promotes flame propagation. The product gas is naturally cooled after combustion, thereby forming a cloud of oxide particles. The obtained oxide particles are charged and captured by an electric dust collector or the like.

  The VMC method uses the principle of dust explosion. According to the VMC method, a large amount of oxide particles can be obtained instantaneously. The resulting oxide particles have a substantially spherical shape. For example, when obtaining silica particles, silicon powder may be added. It is possible to adjust the particle diameter of the resulting oxide particles by adjusting the particle diameter, input amount, flame temperature, and the like of the silicon powder to be input.

<Silica nanoparticles>
The silica nanoparticles constituting the resin composition of the present invention have an average particle diameter of 1 nm to 50 nm. From the viewpoint of facilitating the formation of the close-packed state, the average particle diameter of the silica nanoparticles is preferably 5 nm to 30 nm. The method for producing silica nanoparticles is not particularly limited. For example, examples of the dry method include combustion methods such as the VMC method and the PVS (Physical Vapor Synthesis) method. Moreover, a precipitation method and a gel method are mentioned as a wet method.

<surface treatment>
The spherical silica particles and silica nanoparticles are preferably subjected to a surface treatment in order to improve adhesion with a resin described later. Surface treatment uses, for example, various silane, titanate, aluminate and zirconate coupling agents, cations, anions, amphoteric and neutral surfactants, resins having polar groups such as phenol resins, etc. Can be done. For example, in the surface treatment with a silane coupling agent, a powder to be treated consisting of spherical silica particles and silica nanoparticles is placed in a treatment container, and this powder to be treated is allowed to react with the silane coupling agent vaporized while stirring. That's fine.

  The weight of the treatment agent used for the surface treatment is desirably 10% by weight or less when the weight of the powder to be treated is 100% by weight. This is because if it exceeds 10% by weight, the properties of the resin composition of the present invention may be affected. It is more preferable that the amount be 6% by weight or less. Moreover, in order to fully exhibit the effect of the surface treatment, it is desirable that the weight of the treatment agent is 0.05% by weight or more of the weight of the powder to be treated.

<resin>
The resin constituting the resin composition of the present invention is at least one selected from a curable resin and a thermoplastic resin that are cured by heat or light. Here, examples of the thermosetting resin include an epoxy resin, a silicon resin, a phenol resin, a melamine resin, a urea resin, and an unsaturated polyester resin. Examples of the photocurable resin include acrylic resin (methacrylic resin), silicone resin, and fluororesin. Examples of the thermoplastic resin include polyimide, polyamide resin (polyamideimide, polyetherimide, etc.), polyester (polybutylene terephthalate, polyethylene terephthalate, wholly aromatic polyester, etc.), polysulfone resin, polycarbonate, and the like.

  When the resin composition of the present invention is used as a sealing material for electronic components, an epoxy resin or an acrylic resin may be employed as the resin. As the epoxy resin, oligomers and polymers having two or more epoxy groups in one molecule are suitable. For example, biphenyl type epoxy resin, stilbene type epoxy resin, bisphenol type epoxy resin, triphenol methane type epoxy resin, alkyl modified triphenol methane type epoxy resin, dicyclopentadiene modified phenol type epoxy resin, naphthol type epoxy resin, triazine core containing An epoxy resin etc. are mentioned. One of these may be used alone, or a plurality may be used in combination.

Moreover, as an acrylic resin, the oligomer and polymer obtained by superposing | polymerizing the monomer which has photopolymerizability are suitable. As a photopolymerizable monomer, the monomer shown to (a)-(e) below is mentioned, for example. One kind of the monomers shown in (a) to (e) may be used alone or in combination of two or more kinds, and the resulting oligomer or polymer may be used.
(A) α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, citraconic acid, maleic acid and fumaric acid, and anhydrides and half-esterified products thereof.
(B) α, β-unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, methyl methacrylate, and ethyl methacrylate.
(C) Styrenes such as styrene, α-methylstyrene, and p-vinyltoluene.
(D) Hydroxyl group content such as monoesterified product of acrylic acid and glycol having 1 to 10 carbon atoms such as hydroxymethyl acrylate, hydroxymethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and epoxy ester compound monomer.
(E) Acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, glycidyl acrylate, glycidyl methacrylate.

<Preparation of resin composition>
The resin composition of the present invention is prepared by blending spherical silica particles and silica nanoparticles with a resin. At this time, in order to uniformly disperse the silica nanoparticles in the resin, a slurry in which the silica nanoparticles are dispersed in an organic solvent is prepared in advance, and the resin and the spherical silica particles are mixed with the slurry. For example, when silica nanoparticle powder is used, first, a slurry is prepared by dispersing silica nanoparticle powder in an organic solvent. Next, after mixing resin with this slurry and removing an organic solvent, spherical silica particles may be mixed. In addition, when using a dispersion of silica nanoparticles produced by a wet method, solvent replacement of the dispersion is performed as necessary, and after mixing the resin and removing the solvent, the spherical silica particles are mixed. do it.

  Examples of the organic solvent in which silica nanoparticles are dispersed include methyl ethyl ketone (MEK), N-methyl-2pyrrolidone (NMP), acetone, methyl cellosolve, dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), cyclohexanone, ethyl acetate. , Tetrahydrofuran (THF), isopropyl alcohol (IPA), ether, methylene chloride, xylene, or the like may be used.

  Thus, after dispersing silica nanoparticles in a resin, spherical silica particles are added and melt kneaded with a hot roll, a kneader or the like to obtain the resin composition of the present invention. Using the resin composition of the present invention, an electronic component such as an IC chip can be sealed by a transfer molding method, an injection molding method, a dropping sealing method, or the like.

  The blending amount of the silica filler in the resin composition of the present invention, that is, the total blending amount of the spherical silica particles and the silica nanoparticles is preferably large from the viewpoint of improving heat resistance and moisture absorption resistance. For example, the total amount of the spherical silica particles and the silica nanoparticles may be 85% by weight or more when the total weight of the resin composition is 100% by weight. It is more preferable that the total blending amount of both is 87% by weight or more, further 90% by weight or more.

  Here, the blending amount of the silica nanoparticles is desirably 1% by weight or more and 40% by weight or less of the blending amount of the spherical silica particles. This is because when the content is less than 1% by weight and exceeds 40% by weight, it is difficult to form a close-packed state of silica filler in the resin. It is more preferable that the content be 5 wt% or more and 25 wt% or less.

  The resin composition of the present invention desirably has an embodiment containing a curing agent and a curing catalyst in addition to spherical silica particles, silica nanoparticles, and a resin. As the curing agent, a known curing agent may be used. For example, amine curing agents such as aliphatic polyamine, polyamide polyamine, alicyclic polyamine, aromatic polyamine, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl Examples thereof include anhydride-based curing agents such as hexahydrophthalic anhydride, and phenol-based curing agents such as o-cresol, p-cresol, t-butylphenol, and cumylphenol. As the curing catalyst, a known curing catalyst may be used, and examples thereof include tertiary amines, quaternary ammonium salts, imizodal compounds, boron compounds, and organometallic complex salts. Furthermore, if necessary, colorants such as carbon black and bengara, mold release agents such as natural wax and synthetic wax, silicone oil, ion scavenger, flame retardant, reactive diluent, low stress additives such as rubber You may mix | blend various additives, such as.

  Based on the above embodiment, the resin composition of the present invention was prepared. For comparison, a resin composition not containing silica nanoparticles was also prepared. Hereinafter, description will be made while comparing the Examples and the Comparative Examples.

(1) Example 1
First, silica powder (“AEROSIL-50” manufactured by Nippon Aerosil Co., Ltd., specific surface area 50 m ² / g, average particle diameter 30 nm) was subjected to surface treatment to obtain silica nanoparticle powder. The surface treatment was performed using an epoxy silane (“KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter the same) as a silane coupling agent. The amount of epoxysilane used was 5% by weight of the silica powder.

  Next, the obtained silica nanoparticle powder was dispersed in MEK to prepare a slurry having a silica nanoparticle solid content of 10 wt%. The prepared slurry was stirred with a continuous mill to disperse silica nanoparticles in a primary particle state. 10 parts by weight of a liquid epoxy resin (“ZX-1059” manufactured by Toto Kasei Co., Ltd.) was added to 100 parts by weight of the slurry. And it heated at 120 degreeC, stirring, MEK was removed by evacuating, and the liquid composition whose solid content of a silica nanoparticle is 50 weight% was obtained.

  Next, the silica powder produced by the VMC method (“Admafine SC6200-SEB” manufactured by Admatechs Co., Ltd., average particle diameter 2 μm, sphericity 0.95) is subjected to surface treatment to obtain the first spherical silica. Particle powder was obtained. In addition, a silica powder (“Admafine SC1050-SEP” manufactured by Admatechs Co., Ltd., average particle size 0.2 μm, sphericity 0.95) manufactured by the VMC method is subjected to a surface treatment to obtain a second spherical shape. A powder of silica particles was obtained. All surface treatments were performed using epoxy silane. The amount of epoxysilane used was 0.2% by weight of silica powder for the first powder and 1.6% by weight of silica powder for the second powder.

  Then, to 100 parts by weight of the obtained liquid composition, 328 parts by weight of powder of first spherical silica particles, 72 parts by weight of powder of second spherical silica particles, and 2-PHZ (2 of curing catalyst) -Phenyl-4,5-dihydroxymethylimidazole) 2.5 parts by weight was mixed, heated to 60 ° C., and dispersed with a three-roll. As a result, a fluid resin composition was obtained. When the ash content of the obtained resin composition was measured, the silica filler solid content was 89.2% by weight. In the silica filler, the compounding amount of the silica nanoparticles is 11.9% by weight of the compounding amount of the spherical silica particles. When this resin composition was held at 120 ° C. for 3 hours and further at 150 ° C. for 1 hour, it cured and a resin molded product was obtained.

(2) Comparative Example 1
100 parts by weight of a liquid epoxy resin (“ZX-1059” manufactured by Toto Kasei Co., Ltd.) used in Example 1, 601 parts by weight of powder of the first spherical silica particles, and powder 132 of the second spherical silica particles Part by weight and 5 parts by weight of 2-PHZ as a curing catalyst were mixed, heated to 60 ° C., and dispersed with a three roll. However, the roll did not pass at all, and a resin composition could not be obtained. The silica filler compounding amount in Comparative Example 1 is 87.5% by weight.

(3) Example 2
Silica powder produced by the VMC method (“Admafine SC2500-SEF” manufactured by Admatechs Co., Ltd., average particle size 0.5 μm, sphericity 0.95) is subjected to surface treatment to obtain third spherical silica particles. Of powder. The surface treatment was performed using epoxysilane. The amount of epoxysilane used was 0.6% by weight of the silica powder.

  To 100 parts by weight of a liquid composition containing 50% by weight of silica nanoparticles prepared in Example 1, 358 parts by weight of powder of third spherical silica particles and 5 parts by weight of 2-PHZ as a curing catalyst were mixed, and 60 ° C. And dispersed with three rolls. As a result, a fluid resin composition was obtained. When the ash content of the obtained resin composition was measured, the silica filler solid content was 87.8% by weight. In the silica filler, the compounding amount of the silica nanoparticles is 13.3% by weight of the compounding amount of the spherical silica particles. When this resin composition was held at 120 ° C. for 3 hours and further at 150 ° C. for 1 hour, it cured and a resin molded product was obtained.

(4) Comparative Example 2
100 parts by weight of a liquid epoxy resin (“ZX-1059” manufactured by Toto Kasei Co., Ltd.) used in Example 1, 614 parts by weight of powder of third spherical silica particles used in Example 2, and 2 of the curing catalyst -5 parts by weight of PHZ was mixed, heated to 60 ° C, and dispersed with three rolls. However, the roll did not pass at all, and a resin composition could not be obtained. The amount of silica filler compounded in Comparative Example 2 is 85.4% by weight.

(5) Example 3
Into 100 parts by weight of a liquid composition (“NANOPOX XP 0525” manufactured by Hanse Chenie, solid content of silica nanoparticles 40% by weight) in which the silica sol obtained by the wet method was replaced with a solvent and the solvent was replaced with an epoxy resin. 328 parts by weight of the powder of the first spherical silica particles used in Example 1, 72 parts by weight of the powder of the second spherical silica particles, and 2.5 parts by weight of 2-PHZ of the curing catalyst were mixed, and 60 ° C. And dispersed with three rolls. As a result, a fluid resin composition was obtained. When the ash content of the obtained resin composition was measured, the silica filler solid content was 87.2% by weight. In the silica filler, the compounding amount of the silica nanoparticles is 10.0% by weight of the compounding amount of the spherical silica particles. When this resin composition was held at 120 ° C. for 3 hours and further at 150 ° C. for 1 hour, it cured and a resin molded product was obtained.

(6) Comparative Example 3
In Example 1, 100 parts by weight of a liquid epoxy resin (“YDF-8170C”, BisF type manufactured by Toto Kasei Co., Ltd.) equivalent to the liquid composition used in Example 3 (“NANOPOX XP 0525” manufactured by Hanse Chenie) 601 parts by weight of the powder of the first spherical silica particles used, 132 parts by weight of the powder of the second spherical silica particles, and 5 parts by weight of 2-PHZ of the curing catalyst were mixed and heated to 60 ° C., Dispersed with three rolls. However, the roll did not pass at all, and a resin composition could not be obtained. The amount of silica filler compounded in Comparative Example 3 is 87.5% by weight.

(7) Example 4
A liquid composition (“NANOPOX XP 0746” manufactured by Hanse Chenie), in which the silica sol obtained by the wet method is substituted with a solvent and further substituted with a monomer (2-hydroxyethyl methacrylate), the solid content of silica nanoparticles is 50% by weight ) To 100 parts by weight, 328 parts by weight of the first spherical silica particle powder used in Example 1 and 72 parts by weight of the second spherical silica particle powder were mixed and heated to 60 ° C., Dispersed with three rolls. As a result, a fluid resin composition was obtained. When the ash content of the obtained resin composition was measured, the silica filler solid content was 89.6% by weight. In the silica filler, the compounding amount of the silica nanoparticles is 12.5% by weight of the compounding amount of the spherical silica particles.

(8) Comparative Example 4
100 parts by weight of 2-hydroxyethyl methacrylate (manufactured by Kanto Chemical Co., Inc.), 601 parts by weight of powder of the first spherical silica particles used in Example 1, and 132 parts by weight of powder of the second spherical silica particles Were mixed, heated to 60 ° C., and dispersed with three rolls. However, the roll did not pass at all, and a resin composition could not be obtained. The amount of silica filler compounded in Comparative Example 4 is 88.0% by weight.

(9) Summary As described above in Examples 1 to 4, the resin composition of the present invention has good fluidity even when the silica filler is blended in a large amount of 87% by weight or more, and is a good resin. It was confirmed that the molded product could be molded. On the other hand, as shown in Comparative Examples 1 to 4, when silica nanoparticles were not blended, a resin composition blended with a large amount of silica filler could not be obtained.

Claims (6)

Spherical silica particles having an average particle size of 0.1 μm to 5 μm and a sphericity of 0.8 or more;
Silica nanoparticles having an average particle diameter of 1 nm to 50 nm,
One or more resins selected from a curable resin cured by heat or light, and a thermoplastic resin;
A resin composition comprising:   The resin composition according to claim 1, wherein the spherical silica particles are produced by burning silicon powder.   2. The resin composition according to claim 1, wherein the total amount of the spherical silica particles and the silica nanoparticles is 85 wt% or more when the total weight of the resin composition is 100 wt%.   2. The resin composition according to claim 1, wherein the compounding amount of the silica nanoparticles is 1% by weight or more and 40% by weight or less of the compounding amount of the spherical silica particles.   The resin composition according to claim 1, wherein the resin is an epoxy resin or an acrylic resin.   The resin composition according to claim 1, further comprising a curing agent and a curing catalyst.