JP3434029B2 - Epoxy resin composition - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] Field of the Invention The present invention, when sealing the semi-conductor chip in the resin composition, resistance at the time of soldering also the package an ultrathin The present invention relates to an epoxy resin composition which is capable of producing a package with significantly improved cracking properties and has excellent fluidity, filling properties and moldability. Conventionally, as electronic devices such as memory cards and memory modules have been required to be smaller, thinner, lighter, and have more memory, studies have been made on compounding of devices and thinning of packages. Have been. For example, for compounding of devices, a stacked package adopting a structure in which memory chips are stacked back to back, and a 1 mm thick TS
OP (Thin Small Outline Pac
Kage) type or 2.5 mm thick SOJ (Sm
all Outline J-Bend Packag
e) Types have been announced. Regarding the thickness reduction of the package, an ultra-thin package (for example, 0.5 mm thick paper Thin Pac) that is thinner than the conventional TSOP in order to enable double-sided mounting and multi-stage mounting.
Kage) is under consideration. However, the resin thickness of these laminated packages and ultra-thin packages is about 50 μm at the thinnest part, which is considerably thinner than the ordinary TSOP of about 230 μm, and the conventional sealing resin is used. In this case, there is a problem that it is not possible to perform penetration molding (filling). Also, when mounting the package on a circuit board, the entire package is heated to a high temperature of 200 ° C. or higher and soldered. At this time, cracks occur inside the package due to the explosive vaporization of moisture absorbed during storage. The terrible things could reach the outside. [0004] It is also known to increase the filling rate of the filler in order to improve the crack resistance by reducing the water absorption of the package. In order to apply this technology to a thin package, it is necessary to adjust the filler particle size to a maximum of 45 μm or less. In this case, however, the particle size distribution is narrower than that of a conventional filler having a maximum particle size of 70 to 150 μm. The moldability and formability are reduced, and conversely, the filling rate of the filler must be reduced. As described above, it is difficult to fabricate an ultra-thin package with the conventional sealing resin, and there has been a demand for the emergence of the technology. As chips become larger and packages become thinner in the future, it is desirable to achieve a filler filling rate of 85% by weight or more, and even 90% by weight or more from the viewpoint of crack resistance during soldering. However, under the restriction that the maximum particle must be set to about 45 μm or less, a filler which does not impair the filling property and the moldability at the time of sealing even if high filling is performed has not yet been reported. SUMMARY OF THE INVENTION An object of the present invention is to provide an epoxy resin composition capable of producing a package having a significantly improved crack resistance during soldering even if the package is ultra-thin. To provide things . [0007] That is, the present invention provides (A)
Epoxy resin, (B) hardener and (C) spherical silica powder
And the above (C) spherical silica powder
At the end , a is a value obtained by a water sieving method, b to d are values obtained by a laser diffraction method, and the content of particles having a particle diameter of 45 μm or more is a
% By weight, the content of particles having a particle size of 24 μm or less
The content of particles having a particle diameter of 8 μm or less is c weight%, and the particle diameter is 3 μm.
When the content of particles having a particle size of m or less is d weight%, a ≦ 0.
5, 40 ≦ b ≦ 90, 30 ≦ c ≦ 75, 20 ≦ d ≦ 60
, And b / d = 1 to 3 is also an epoxy resin composition. Hereinafter, the present invention will be described in more detail. The reason for using the spherical silica powder in the present invention is to meet the low linear expansion coefficient and moisture resistance required for the sealing resin. In addition, calcium carbonate, barium sulfate, silicon nitride and the like easily cause hydrolysis, and the moisture resistance of the semiconductor component deteriorates. Also,
In the case of crushed silica powder, the flowability of spherical silica powder cannot be exceeded, no matter how the particle size composition is adjusted within a conceivable range. [0010] The spherical silica powder of the present invention comprises silica, silica sand,
Quartz or the like is ground by an appropriate method such as a vibrating mill or the like, and is injected into a flame such as LPG / oxygen or high-temperature plasma to form a spheroid. The starting material is spherical granulated by a spray drier or the like and subjected to sintering or flame spraying to form a spheroid, and furthermore, metal silicon or alkoxysilane is used as a starting material and synthesized and spheroidized in a gas phase or a liquid layer. Whatever is manufactured by any method can be used. The particle shape of the spherical silica powder of the present invention is preferably closer to a true sphere because better characteristics can be exhibited. However, the spherical silica powder need not necessarily be a perfect sphere, and the sphericity need not be extremely bad. . If the sphericity is expressed by the ratio of the major axis / minor axis of the particles, those having a sphericity of 1.0 to 1.3 are preferable. A major feature of the present invention is that the particle size composition of the spherical silica powder is as described above, and the a value is 0.5.
If the content is more than 10% by weight, poor filling properties during molding (such as sink marks and welds) are likely to occur, and the b value, c value, d value and b
If the / d ratio is other than the above, the spiral flow value, that is, the fluidity is reduced, and the burr characteristics are deteriorated. [0013] Even in the above particle size configuration, 50 ≦ b ≦ 8
0, 40 ≦ c ≦ 65, 30 ≦ d ≦ 50,
Moreover, those having a particle size distribution of b / d = 1 to 2.5 are preferable, and more preferably 55 ≦ b ≦ 75 and 45 ≦
c ≦ 60, 30 ≦ d ≦ 45, and b /
It has a particle size distribution satisfying d = 1 to 2. In the case of such a particle size configuration, the filling property and the fluidity are further improved, and high filling can be achieved without impairing the moldability. In the present invention, the value a is determined by the water sieving method, the value b is
The reason for using the laser diffraction method for the value and the d value is from the viewpoint of measurement accuracy. Details of these measurements will be described later. The epoxy resin of the component (A) used in the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule, and specific examples thereof include phenol novolak type epoxy resins, Orthocresol novolak type epoxy resin, epoxidized novolak resin of phenols and aldehydes, obtained by reaction of epichlorohydrin with glycidyl ethers such as bisphenol A, bisphenol F and bisphenol S, and polybasic acids such as phthalic acid and dimer acid. Glycidyl ester acid epoxy resin, other, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin,
Alkyl-modified polyfunctional epoxy resin, β-naphthol novolak type epoxy resin, 1,6-dihydroxynaphthalene type epoxy resin, 2,7-dihydroxynaphthalene type epoxy resin, bishydroxybiphenyl type epoxy resin, and further imparts flame retardancy For this purpose, there are epoxy resins into which halogen such as bromine is introduced, and one or more of these are used. Particularly, from the viewpoints of solder heat resistance and moisture resistance reliability, ortho-cresol novolak type epoxy resin, bishydroxybiphenyl type epoxy resin, and epoxy resin having a naphthalene skeleton are preferable. The curing agent of the component (B) used in the present invention is not particularly limited as long as it reacts with the epoxy resin (A) and cures. For example, phenol, cresol, xylenol, resorcinol, chlorophenol A novolak resin obtained by reacting at least one or a mixture of two or more selected from the group consisting of t-butylphenol, nonylphenol, isopropylphenol, octylphenol and the like with formaldehyde, paraformaldehyde or para-xylene under an oxidation catalyst; Polyparahydroxystyrene resin, bisphenol compounds such as bisphenol A and bisphenol S, trifunctional phenols such as pyrogallol and phloroglucinol, maleic anhydride, acid anhydrides such as phthalic anhydride and pyromellitic anhydride, Data phenylenediamine, diaminodiphenylmethane, and aromatic amines such as diaminodiphenyl sulfone. In the present invention, (A) an epoxy resin,
In the epoxy resin composition containing (B) the curing agent and (C) the spherical silica powder, the proportion of the component (C) is as follows:
It is preferably 80 to 95% by weight based on the total amount of (B) and (C). When the proportion of the component (C) is less than 80% by weight, the strength of the resin composition is reduced or the water absorption is increased, so that crack resistance during soldering is reduced. On the other hand, if it exceeds 95% by weight, the spiral flow value becomes small even if the optimum particle size distribution and the optimum specific surface area are selected, unfilling occurs during molding, the die pad on which the chip is mounted fluctuates, and furthermore, the semiconductors There is a risk that the bonding wire connecting the element and the lead may be deformed or cut. In particular, when the die pad fluctuates, package cracks easily occur during soldering. The epoxy resin composition of the present invention may contain the following components as required in addition to the components (A) to (C). That is, as a low stress agent,
Rubber-like substances such as silicone rubber, polysulfide rubber, acrylic rubber, butadiene-based rubber, styrene-based block copolymer and saturated elastomer, various thermoplastic resins, resinous substances such as silicone resins, and epoxy resins and phenolic resins. Examples of silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, β- (3,4-
Epoxy silane such as epoxycyclohexyl) ethyltrimethoxysilane, aminosilane such as aminopropyltriethoxysilane, ureidopropyltriethoxysilane, N-phenylaminopropyltrimethoxysilane, phenyltrimethoxysilane, methyltrimethoxysilane, octadecyltrimethoxysilane As a surface treatment agent such as a hydrophobic silane compound such as a mercaptosilane,
Sb ₂ O ₃ , Zr chelate, titanate coupling agent, aluminum-based coupling agent, etc.
_{Sb 2 O 4, Sb 2 O} 5 , etc., as flame retardants, halogenated epoxy resin and a phosphorus compound, as a coloring agent, carbon black, iron oxide, dyes, pigments and the like. In particular, when high moisture resistance reliability and high-temperature storage stability are required, the addition of various ion trapping agents is effective. Specific examples of the ion trapping agent include Kyowa Chemical's trade names “DHF-4A”, “KW-2000”,
"KW-2100" and a product name "IX-6" manufactured by Toa Gosei Co., Ltd.
00 ”and the like. The epoxy resin composition of the present invention may contain a curing accelerator for accelerating the reaction between the epoxy resin and the curing agent. Examples of the curing accelerator include those described above, and an organic phosphine compound and a cycloamidine derivative are particularly preferable in terms of heat resistance and moisture resistance. Further, an imide compound such as a bismaleimide can be blended to further improve heat resistance. [0021] The epoxy resin composition of the present invention may further contain a release agent such as a wax, if necessary. Specific examples thereof include natural waxes, synthetic waxes, metal salts of straight-chain fatty acids, acid amides, esters, and paraffin. The epoxy resin composition of the present invention is produced by mixing the above-mentioned materials in a blender or a mixer, and then melt-kneading them by means of a heating roll, kneader, extruder, Banbury mixer or the like, and cooling and pulverizing. can do. In order to seal a semiconductor chip with a resin using the epoxy resin composition of the present invention, it is sufficient to cure and mold by a known molding method such as transfer molding and multi-plunger. In addition to satisfying general properties such as heat resistance and thermal conductivity, excellent moldability can be maintained despite the high filler filling rate. EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the examples below, all parts and percentages are shown on a weight basis. Examples 1 to 10 Comparative Examples 1 to 7 Spherical silica powders having the particle sizes shown in Table 1 (Examples 1 to 10) and Table 2 (Comparative Examples 1 to 7) were used. It was blended with each material at a ratio and dry blended by a mixer. This was heated and kneaded for 5 minutes using a mixing roll having a roll surface temperature of 100 ° C., and then cooled and pulverized to obtain 17 different epoxy resin compositions. The spherical silica powder used here was produced by putting silica stone powder into an LPG / oxygen flame, and had an average sphericity (ratio of major axis / minor axis) of 1.2. . The values a, b, c, and d of the granularity configuration
The value was measured as follows. (A value) Water sieving method: After 200 g of a sample is put into a 45 μm sieve and sieved while applying shower water, the residue on the sieve is rinsed in an aluminum container, and the supernatant is discarded and dried. The obtained dried product was sieved with a 45 μm sieve, and the ratio of the residue on the sieve was calculated. (B value, c value and d value) Laser diffraction method: 0.1 to 0.5 g of a sample was dispersed in water, and the dispersion was measured with a laser diffraction type particle size distribution analyzer (Cirrus Granulometer “Model 715”). . The 17 types of epoxy resin compositions obtained as described above were evaluated for gel time, spiral flow (SF), burrs, filling properties, and crack resistance during soldering according to the following. Table 4 shows the results.
Shows the results of Examples 1 to 10, and Table 5 shows the results of Comparative Examples 1 to 7. (1) Gel Time The time until the resin composition melted and hardened on the metal block heated to 175 ° C. was measured. (2) Spiral flow (SF) Using a spiral flow mold, EMMI1-66 (E
POXY MOLDING MATERIAL INS
title; Society of Plast
ic Industry). The molding temperature is 175 ° C. (3) Burrs Molded using a burr mold having slits of 2 μm, 5 μm, 10 μm and 30 μm, and the length of the burr was measured. The molding temperature is 175 ° C. (4) Fillability and crack resistance during soldering Using a mold prototyped so that the thickness of the tree above and below the chip is 55 μm, 175 ° C. by low-pressure transfer molding
48 pin TSOP in which the simulation element is sealed under the condition of × 2 minutes
After producing 18 compacts (packages), 175 ° C x
Post-curing was performed for 5 hours. These packages were visually inspected, and the number of packages in which defective filling (poor appearance) was recognized was measured to evaluate the filling property. In addition, all of these packages are stored at a temperature of 40 ° C. and a humidity of 80% RH.
After immersion in solder at 260 ° C. for 10 seconds, the number of packages in which internal cracks were observed was measured by an ultrasonic probe, and evaluated for crack resistance. [Table 1] (Note) All a values are 0.5% by weight or less. [Table 2] [Table 3] [Table 4] [Table 5] [0034] [0035] According to the epoxy resin composition of the present invention,
It is suitable for use as an ultra-thin electronic component for surface mounting, particularly as a sealing material for semiconductors and the like. Even if the package is ultra-thin, it is possible to produce a package having excellent crack resistance during soldering.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-261856 (JP, A) JP-A-63-159422 (JP, A) JP-A-5-136296 (JP, A) JP-A-5-136296 1208 (JP, A) JP-A-3-265623 (JP, A) JP-A-1-266152 (JP, A) JP-A-1-263131 (JP, A) JP-A-2-145416 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C01B 33/18 C08L 63/00 C08K 3/36

Claims (1)

(57) [Claims] ( 1 ) An epoxy resin, (B) a curing agent and
(C) a composition containing spherical silica powder,
(C) spherical silica powder , a is a value obtained by a water sieving method, b to
d is a value obtained by a laser diffraction method, and the particle diameter is 45 μm.
The above particle content was defined as a weight%, the particle content of a particle size of 24 μm or less as b weight%, the particle content of a particle size of 8 μm or less as c weight%, and the particle content of a particle size of 3 μm or less as d weight%. When a ≦ 0.5, 40 ≦ b ≦ 90, 30 ≦ c ≦ 7
5, 20 ≦ d ≦ 60, and b / d = 1
An epoxy resin composition, which is an epoxy resin composition.