JPH10120878A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin compsn. which has a low melt viscosity and a good moldability and, when used for sealing a semiconductor device, gives a highly reliable semiconductor device free from die pad deformation, wire deformation, etc. SOLUTION: This compsn. essentially contains an epoxy resin, a curative, and 80-90wt.% (based on the compsn.) inorg. filler. The filter contains 10-40wt.% particles having particle sizes of 3μm or lower and has a specific surface area by the BET method (the nitrogen adsorption method) of 2.5m<2> /g or lower. When the filler in an amt. of 75wt.% is mixed into a liq. bisphneol F type epoxy resin having a viscosity (measured at 25 deg.C by Gardner-Holdt method) of 30-45P, the resultant mixture has such a viscosity (measured at 25 deg.C with an E-type viscometer) that the viscosity at a shear rate of 0.6sec<-1> is 50,000P or lower and that the ratio of the viscosity measured at a shear rate of 0.6sec<-1> to that measured at a shear rate of 10sec<-1> is 2.5 or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a low melt viscosity resin,
The present invention relates to an epoxy resin composition which has excellent moldability and can prevent damage to a semiconductor device when a thin, multi-pin semiconductor device is sealed, and a semiconductor device sealed with a cured product of the composition.

[0002]

2. Description of the Related Art In recent years, epoxy resin compositions as sealing materials for thin packages have been used in order to achieve both improved fillability and low water absorption.
Very fine average particle size is 1 μm or less, preferably 0.5 μm
There is a tendency to add a large amount of a filler of μm or less. For this reason, the specific surface area of the filler is much larger than that of the conventional product, and the wetting of the interface between the resin and the filler is significantly deteriorated.

On the other hand, recently, in order to improve the solder reflow resistance, there has been a trend toward increasing the amount of filler to reduce water absorption. In particular, when the filling amount is 85% by weight or more, the viscosity of the conventionally used spherical filler in the low-shear region becomes extremely high, causing die pad deformation, wire deformation, and in some cases, disconnection.

The present invention has been made to improve the above circumstances, and has an epoxy resin composition having a low melt viscosity, high moldability, and capable of sealing a semiconductor without damage such as die pad deformation and wire deformation. It is an object to provide a semiconductor device sealed with a cured product of the composition.

[0005]

Means for Solving the Problems and Embodiments of the Invention In order to achieve the above object, the present inventors have made intensive studies on an inorganic filler which is highly filled in an epoxy resin composition. That is, in general, the particle size and specific surface area of a fine region are not controlled in a conventionally produced inorganic filler. Therefore, when a large amount of the filler is blended, the viscosity of the resin composition sharply increases in a low shear region. Recently, the problem of thickening and causing wire deformation has become a major problem, and the present inventors have aimed at improving this kind of defect and at the same time reducing the viscosity at the time of high filling of the inorganic filler. As previously proposed, the particle size distribution, specific surface area and shape of the inorganic filler were studied. That is,
The proposals for conventional inorganic fillers are all those in which the molding properties are defined by the properties of the inorganic filler, such as the particle size distribution, specific surface area, and shape, and the present inventors have followed this. . However, the relationship between the various properties of the filler and the moldability has not been completely grasped in the past. It has been difficult to prevent the above-mentioned defects that are likely to occur.

Therefore, as a result of further study, a composition was prepared in which a filler having a specific particle size and specific surface area was blended, and the viscosity was measured while changing the shear rate to obtain a specific viscosity ratio. It has been found that a composition having good moldability can be obtained by using a filler.

That is, an epoxy resin, a curing agent, and an inorganic filler
Epoxy resin composition containing an agent as an essential component,
10-40 weight of inorganic filler as a filler
% Of fine particles having a particle size of 3 μm or less.
Surface area by the BET method (nitrogen adsorption method)
m^Two / G or less and at 25 ° C Gardner Holt
With a viscosity of 30 to 45 poise when measured by the method
Inorganic filler 75 in phenol F type liquid epoxy resin
The kneaded mixture obtained by kneading the weight% was subjected to an E-type viscometer at 25 ° C.
0.6 / sec and 10 / sec when measured using
Is 2.5 or less, and the viscosity at 0.6 / sec.
Uses an inorganic filler with a degree of 50,000 poise or less
And blending it in an amount of 80 to 90% by weight of the whole composition.
Therefore, even if the inorganic filler is highly filled in this way,
Low degree, excellent moldability, and disadvantages such as wire deformation
To be able to seal thin, multi-pin semiconductor devices
Thus, the present invention has been accomplished.

Accordingly, the present invention relates to an epoxy resin composition comprising an epoxy resin, a curing agent and an inorganic filler as essential components, wherein the above specific inorganic filler is contained in the entirety of the composition.
It is intended to provide an epoxy resin composition blended with a composition of about 90% by weight and a semiconductor device sealed with a cured product of the composition.

Hereinafter, the present invention will be described in more detail. The epoxy resin composition of the present invention contains an epoxy resin, a curing agent, and an inorganic filler as essential components.

The epoxy resin used in the present invention includes:
Any conventionally known one having two or more epoxy groups per molecule can be used, and in particular, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak Type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, phenol aralkyl type epoxy resin, cyclopentadiene type epoxy resin and the like. Among these epoxy resins, those having a naphthalene type epoxy resin, a biphenyl type epoxy resin and a liquid crystal structure represented by the following structural formula are preferable.

[0011]

Embedded image

The total chlorine content in these epoxy resins is 1,500 ppm or less, desirably 1,000 ppm or less, and the amount of chlorine extracted from water in 120 hours at 120 ° C. and 50% epoxy resin concentration is 5 ppm or less. Is preferred. If the total chlorine content is more than 1,500 ppm and the amount of chlorine in the extracted water is more than 5 ppm, the moisture resistance reliability of the semiconductor may be reduced.

As the curing agent of the present invention, any of the curing agents conventionally known as epoxy resin curing agents such as phenol compounds, amine compounds and acid anhydride compounds can be used. Phenolic resins having two or more phenolic hydroxyl groups therein are preferred.
Examples of the phenol resin include a phenol novolak resin, a cresol novolak resin, a phenol aralkyl resin, a naphthalene-type phenol resin, a cyclopentadiene-type phenol resin, and those containing a phenolic hydroxyl group represented by the following structural formula.

[0014]

Embedded image (Wherein, R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group are shown. n is an integer of 0-5. )

[0015] The phenolic resin, like the epoxy resin, is 12
Chlorine ions and sodium ions extracted at a temperature of 0 ° C. are all 10 ppm or less, preferably 5 ppm or less.

The amount of the curing agent is such that the epoxy resin can be cured. For example, when a phenol resin is used,
The mixing ratio of the epoxy resin and the phenol resin is preferably 0.5 to 1.6 mol, more preferably 0.6 to 1.4 mol, of the phenolic hydroxyl group per 1 mol of the epoxy group. If the amount is less than 0.5 mol, the hydroxyl group becomes insufficient, the homopolymerization ratio of the epoxy group increases, and the glass transition temperature decreases. On the other hand, if it exceeds 1.6 mol, the ratio of the phenolic hydroxyl group increases, the reactivity decreases, and the crosslink density is low, so that sufficient strength may not be obtained.

The epoxy resin composition of the present invention may contain a curing accelerator. As the curing accelerator, phosphorus-based, imidazole derivatives, cycloamidine-based derivatives and the like can be used. The amount of the curing accelerator is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the phenol resin.

Next, in the present invention, an inorganic filler and
And 10 to 40% by weight of the entire inorganic filler is 3 μm or less.
Lower fine particles, BET as inorganic filler as a whole
2.5m specific surface area by the nitrogen method^Two / G or less
And measured by the Gardner-Holt method at 25 ° C.
Bisphenol F having a viscosity of 30 to 45 poise
75% by weight of inorganic filler is kneaded with a liquid epoxy resin
The kneaded mixture was measured at 25 ° C. using an E-type viscometer.
In the case where the viscosity ratio between the shear rate of 0.6 / sec and 10 / sec is
2.5 or less and a viscosity at 0.6 / sec of 50,0
Uses an inorganic filler that is not more than 00 poise
You.

More specifically, the particle size distribution of the inorganic filler used in the present invention is such that the filler having a fine particle size of 3 μm or less is 10 to 40%, more preferably 0.05 to 0.
1 to 10% of 3 μm filler, 5 to 20% of 0.4 to 0.7 μm filler, 5 to 20 of 0.8 to 3 μm filler
%belongs to. If the filler is less than 10%, the melt viscosity of the composition is not sufficiently reduced due to insufficient fine packing. Conversely, the viscosity of the composition increases because it does not wet. Desirably, a filler of 3 μm or less is contained in the range of 10 to 30%.

In this case, the average particle diameter of the filler as a whole is preferably 4 to 30 μm. Average particle size is 4μm
If it is smaller, the viscosity will be too high to fill a large amount,
If it is larger than 30 μm, the coarse particle size increases, and there is a possibility that the gate may be clogged. Further, it is preferable to have a particle size distribution having a maximum particle size of 100 μm or less, more desirably 74 μm or less.

In the present invention, the closest packing of the filler is
Of viscosity of resin composition and resin composition by filling and thixotropic property
Filler with particle size of 0.7μm or less is very
Play an important role. More desirable filler is 0.05-
0.3 μm fine powder filler. This kind of filler is ball
Desirable, specific surface area is 10-50m^Two / G
Good. More preferable specific surface area of the filler is 15 to 40 m^Two
/ G.

In this case, conventionally, a thixotropic property is imparted by aerobic.
Specific surface area of dry or wet type represented by Jill is 100
~ 300m^Two / G and very large ultra-fine silica are mainly used
However, this material has a large specific surface area,
Since the addition greatly affects the fluidity,
Very difficult to use.

In the present invention, the particle size distribution and the average particle size are values (for example, weight average value) measured by a laser diffraction type particle size distribution analyzer (eg, Granulometer 920, manufactured by Cirrus Co., Ltd.).

Next, the inorganic filler of the present invention is
2.5m specific surface area by BET method (nitrogen adsorption method)^Two
/ G or less, desirably 1-2 m^Two / G. Specific surface area
Is 2.5m^Two / G, the thixotropy increases.
As a result, good molding characteristics intended in the present invention cannot be obtained.
It becomes.

The inorganic filler of the present invention has a temperature of 25 ° C.
Using a E-type viscometer, a kneaded product obtained by kneading 75% by weight of a bisphenol F type liquid epoxy resin having a viscosity of 30 to 45 poise as measured by the Gardner-Holt method at (± 0.05 ° C.) was used. 05 ° C.) the viscosity ratio V ₁ / V ₂ between shear rate 0.6 / sec viscosity V ₁ of the measured shear rate of 10 / sec viscosity V ₂ at use 2.5 or less. When V ₁ / V ₂ of more than 2.5 is used, the resin viscosity when flowing in the cavity becomes extremely high,
This results in wire deformation and die pad shift. Among them, the viscosity ratio is 0.5 to 2.5, especially 0.8 to
The use of the filler of 2.2 can prevent a sharp increase in resin viscosity in a low shear region. In this case, a shear rate of 0.
The viscosity V ₁ of the 6 / s 50,000 poises, especially 5,000 to 30,000 poise, the viscosity is 5
If it exceeds 000 poise, the viscosity of the epoxy resin composition becomes extremely high, and the moldability deteriorates.

By blending this kind of inorganic filler, 1
The melt viscosity of the epoxy resin composition at 75 ° C. is 200
Poise or less can be obtained, and a composition having good molding characteristics can be obtained.

The specific surface area of the inorganic filler is high shear.
Greater than the ratio of viscosity at speed to viscosity at low shear rates
Has been affected. That is, the specific surface area is 2.5 m^Two / G or less
Therefore, it is possible to reduce the viscosity ratio to 2.5 or less.
And found. Above this point, wetting of the resin-filler interface
Insufficient, viscosity is extremely high, and viscosity ratio exceeds 2.5
It will be something you can get. Further, this viscosity ratio is such that the particle size is 0.1.
7μm or less, especially for 0.05-0.3μm fine filler
Affected by The filler in this area is easily shaken
Has the property of easy aggregation
In such cases, the effect becomes particularly significant. To prevent this secondary agglomeration
Or wet the resin-filler interface sufficiently.
It is desirable to knead it.

Examples of the filler used in the present invention include fused silica pulverized by a ball mill or the like, spherical silica obtained by flame melting, spherical silica produced by a sol-gel method, crystalline silica, alumina, boron nitride and the like. ,
Aluminum nitride, silicon nitride, magnesia, magnesium silicate and the like are used. When the semiconductor element is an element generating a large amount of heat, the thermal conductivity is as large as possible and the expansion coefficient is small, such as alumina, boron nitride, aluminum nitride,
It is desirable to use silicon nitride or the like as a filler. Further, it may be used by blending with fused silica or the like. In this case, the shape of the filler is not particularly limited, and flake-like, dendritic, spherical, or other fillers can be used alone or in combination. Among them, spherical ones are most desirable for low viscosity and high filling. It is preferable to use those fillers that have been surface-treated with a silane coupling agent or a titanium-based coupling agent in advance.

The amount of the inorganic filler is from 80 to 90% by weight of the whole composition, and usually from 400 to 1,000 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the curing agent. If the compounding amount is too small, the expansion coefficient cannot be sufficiently reduced, the water absorption rate also increases, and the package will crack at the temperature during solder reflow. On the other hand, if it is too large, the viscosity becomes too high, and molding cannot be performed.

The composition of the present invention can reduce the stress of conventionally known powders such as silicone rubber and gel, silicone-modified epoxy resin, silicone-modified phenol resin, and thermoplastic resin composed of methyl methacrylate-butadiene-styrene. It may be added as an agent.

For the purpose of lowering the viscosity, conventionally known n-butyl glycidyl ether, phenyl glycidyl ether, styrene oxide, tert-butylphenyl glycidyl ether, dicyclopentadiene diepoxide, phenol, cresol, tert-butylphenol And a diluent having an epoxy group or a phenolic hydroxyl group.

Further, coupling agents such as silane coupling agents, titanium coupling agents, aluminum coupling agents and the like, coloring agents such as carbon black, nonionic surfactants, fluorine surfactants, silicone oils and the like. A wetting improver, an antifoaming agent, and the like can be optionally added.

As for the production method, in the case of a liquid epoxy resin composition, it can be produced by sufficiently kneading the above-mentioned raw materials using a stirring and mixing device such as a Shinagawa mixer. The kneading temperature is preferably from 20 to 50C. on the other hand,
In the case of powder, it is sufficient that the powder is uniformly mixed using a high-speed mixer or the like, and then sufficiently kneaded with a two-roll or continuous kneading device. The kneading temperature is preferably from 50 to 110C.

After kneading, the sheet is formed into a thin sheet, cooled and pulverized to produce an epoxy resin composition. The resin composition of the present invention is used as a general molding material and further as a semiconductor sealing material.

As a molding method, methods such as transfer molding, compression molding, and injection molding can be adopted, and the molding temperature is preferably from 150 to 185 ° C.

The semiconductor device suitably sealed with the epoxy resin composition of the present invention includes a discrete device, a highly integrated device such as an IC, an LSI, and a super LSI.

[0037]

The epoxy resin composition of the present invention has a low melt viscosity and good moldability, and a semiconductor device sealed with this composition has no die pad deformation, no wire deformation, etc., and is highly reliable. .

[0038]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Examples 1 to 3 and Comparative Examples 1 to 5
After surface treatment of fillers (silica) A to H represented by the following formula with 0.5% by weight of the filler of γ-glycidyloxypropyltrimethoxysilane; KBM403 (manufactured by Shin-Etsu Chemical Co., Ltd.), the characteristics of the filler evaluated. Also, this silica is shown in Table 2.
And an epoxy resin composition was prepared by mixing and kneading with the above composition. Furthermore, various evaluations were performed using this resin composition. Table 2 shows the results.

[0040]

[Table 1]

Particle size distribution and average particle size: The particle size distribution was measured using a laser diffraction / scattering type particle size distribution analyzer. Specific surface area: The specific surface area of the filler mixed in the above ratio was measured by a specific surface area measuring device (BET method, nitrogen adsorption method). Viscosity ratio and viscosity at 0.6 / sec: epoxy equivalent 168,
Bisphenol F type epoxy resin having a viscosity of 38 poise (25 ° C.); 1 g of Epicoat 807 (manufactured by Shell Co., Ltd.) and 3 g of silica were weighed and sufficiently kneaded on a glass petri dish, and then RU was provided as a rotor cone. Using an E-type viscometer (manufactured by Toki Sangyo), the viscosity was measured at 25 ° C. ± 0.05 ° C. at a shear rate of 0.6 / sec (V ₁ ) and 10 / sec (V ₂ ), and the ratio V ₁ was measured. / I took the V _2.

[0042]

[Table 2] * 1 Biphenyl-type epoxy resin (Yukaka Shell Co., Ltd.)
* 2 Naphthalene type epoxy resin (Nippon Kayaku Co., Ltd.) * 3 Phenol novolak resin (Dainippon Ink & Chemicals, Inc.) * 4 Brominated novolak type epoxy resin (Nippon Kayaku Co., Ltd.)

Spiral flow: molding temperature 175 ° C.
Forming pressure 70kg / cm^Two Transfer molding by
Measured the spiral flow. Gelation time: The epoxy resin composition was gelled on a hot plate at 175 ° C.
The time required to reach the maximum was measured. Inner void and outer void: QFP package (Sump
Molding temperature 175 ° C, molding pressure 70k
gf / cm^Two Ultrasonic inspection after transfer molding by
The number of internal voids was counted using the instrument. Also, external boys
De counted the number of voids by visual observation. Void
The number is the total number of 5 samples. Wire deformation: QFP package with 3mm long gold wire connected
175 ° C, molding pressure 70kgf /
cm^Two Transfer molding, then use soft X-ray equipment
Then, the degree of deformation of the gold wire was observed. Die pad deformation: QFP package, molding temperature 1
75 ° C, molding pressure 70kgf / cm^Two Transfer by
After molding, cut the package and deform the die pad.
Condition was observed.

Examples 4 and 5, Comparative Example 6 An epoxy resin composition was produced in the same manner as in Example 1 with the composition shown in Table 3 below, and evaluated in the same manner as in Example 1. The results are also shown in Table 3.

[0045]

[Table 3] * 5 Phenol aralkyl resin (Mitsui Toatsu Chemical Co., Ltd.)
Made)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Shiohara 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronic Materials Research Laboratory Shin-Etsu Chemical Co., Ltd. (72) Inventor Eiichi Asano Matsui, Usui-gun, Gunma Prefecture 1-10 Tenmachi Hitomi, Silicon Electronic Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Kazutoshi Tomiyoshi 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture 10 Silicone Electronic Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd.

Claims (2)

[Claims] 1. An epoxy resin, a curing agent, and an inorganic filler.
In the epoxy resin composition, which is an essential component,
10 to 40% by weight of the whole filler is fine particles of 3 μm or less.
Yes, BET method (nitrogen adsorption)
Method) 2.5m^Two / G or less
And the viscosity as measured by the Gardner-Holt method at 25 ° C
Bisphenol F type liquid epo having 30 to 45 poise
A kneaded product obtained by kneading 75% by weight of the inorganic filler with a hydroxy resin
When measured using an E-type viscometer at 25 ° C.
Viscosity ratio of cutting speed of 0.6 / sec to 10 / sec is 2.5 or less
And the viscosity at 0.6 / sec is 50,000 poise
The following inorganic filler is used in an amount of 80 to 90% by weight of the whole composition.
% Epoxy resin composition. 2. A semiconductor device sealed with a cured product of the epoxy resin composition according to claim 1.