JPH1053694A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable semiconductor product having excellent moldability such as flowability and suppression of burr generation, a cured product having low moisture absorption and excellent reflow resistance, and excellent moldability. An epoxy resin composition and a semiconductor device capable of manufacturing the same with high productivity. SOLUTION: In an epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler, as an inorganic filler, 97% by weight or more has a particle size of 25 μm or less, and an average particle size is less than 2.5 μm; An inorganic filler containing at least 1% by weight or more of fine fused silica previously uniformly mixed with an epoxy resin and / or a curing agent is used. The semiconductor device is sealed with the cured product of the epoxy resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition which gives a highly reliable cured product when molding a surface mounting package, and a semiconductor device sealed with the cured product.

[0002]

2. Description of the Related Art
In the semiconductor industry, resin-sealed diodes, transistors, ICs, LSIs, and super LSIs have become mainstream,
Among them, epoxy resin, epoxy resin composition containing a curing agent and various additives are generally excellent in moldability, adhesiveness, electrical properties, mechanical properties, moisture resistance, etc. as compared with other thermosetting resins. In many cases, a semiconductor device is sealed with an epoxy resin composition.

In recent years, the degree of integration of these semiconductor devices has been increasing, and the chip size has been increasing accordingly. On the other hand, package dimensions have been reduced due to the demand for smaller and lighter electronic devices.
Thinning is progressing. Furthermore, in the method of attaching a semiconductor component to a circuit board, surface mounting of the semiconductor component has been widely performed in order to increase the density of components on the board.

However, when a semiconductor device is surface-mounted, it is common to immerse the entire semiconductor device in a solder bath or to pass the semiconductor device through a high-temperature zone in which the solder melts. Cracks occur in the layer, and peeling occurs at the interface between the lead frame or chip and the sealing resin. Such cracks and peeling become more remarkable when the sealing resin layer of the semiconductor device absorbs moisture before the thermal shock at the time of surface mounting, so that the inorganic filler is highly filled to suppress the amount of moisture absorption. Is being considered.

Furthermore, in order to reliably fill a thin package or the like when molding, it is necessary to lower the viscosity of the sealing resin. In some cases, the reliability at the time of molding such as filling is greatly impaired.

[0006] Therefore, as a means for solving these problems, there are known methods such as adding silica having various particle diameters to an epoxy resin composition, and using a high-viscosity epoxy resin or a phenol resin. However, with these methods, a decrease in fluidity, a decrease in solder reflow resistance, and the like are observed, and it is difficult to completely satisfy the recent demands for increasingly sophisticated semiconductor device sealing.

The present invention has been made in view of the above circumstances, and provides a cured product having good fluidity and excellent solder reflow resistance and moldability of a surface mounting package, and sealing with the cured product. It is an object of the present invention to provide an epoxy resin composition which gives a highly reliable semiconductor device by doing so and a semiconductor device sealed with a cured product of this composition.

[0008]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that an epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler is 9 as inorganic filler
7% by weight or more has a particle size of 25 μm or less and an average particle size of less than 2.5 μm, and at least 1% by weight of fine fused silica previously uniformly mixed with an epoxy resin and / or a curing agent in the entire inorganic filler. By using those containing above, fine fused silica having a large specific surface area, a small specific gravity, and having difficulty in uniform dispersibility with a resin component such as an epoxy resin or a phenol resin by simple blending is uniformly mixed with the above resin component. A cured product that has good fluidity, can suppress the occurrence of burrs during molding, has excellent moldability, and has low moisture absorption and excellent solder reflow resistance of surface mount packages. Is found that an epoxy resin composition giving the following can be obtained, and that a highly reliable semiconductor device can be manufactured with high productivity by sealing with the cured product. I've reached the point.

Accordingly, the present invention provides an epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler, wherein 97% by weight or more of the inorganic filler has a particle size of 25 μm.
m and an average particle size of less than 2.5 μm, and containing at least 1% by weight or more of fine fused silica previously uniformly mixed with an epoxy resin and / or a curing agent in the entire inorganic filler. And a semiconductor device sealed with a cured product of the epoxy resin 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.

Here, as long as the epoxy resin is a compound having at least two epoxy groups in the molecule, its molecular structure, molecular weight and the like are not particularly limited, and specifically, phenol novolak type epoxy resin, biphenyl type epoxy resin and the like. Epoxy resins, bisphenol-type epoxy resins, aralkyl-type epoxy resins, polyfunctional epoxy resins, dicyclopentadiene-containing epoxy resins, naphthalene-ring-containing epoxy resins, heterocyclic-type epoxy resins, and epoxy resins obtained by introducing halogen atoms into these resins can do.

In the present invention, it is particularly desirable to use a biphenyl type epoxy resin represented by the following general formula (1) as the epoxy resin.

[0013]

Embedded image(Where R Is a hydrogen atom, a halogen atom or a carbon atom 1
And q is an integer of 0-5. )

In the above formula (1), R represents a hydrogen atom, a bromine atom, a halogen atom such as a chlorine atom or a fluorine atom, a carbon atom having 1 to 1 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group. And 5 alkyl groups.

The amount of the biphenyl type epoxy resin of the formula (1) is preferably at least 20% by weight, especially at least 50% by weight, based on the total amount of the epoxy resin compounded in the composition. If the blending amount of the biphenyl type epoxy resin of the formula (1) is less than 20% by weight, low hygroscopicity may not be obtained, crack resistance upon thermal shock after moisture absorption is not sufficiently improved, and high fluidity is obtained. Since moldability cannot be obtained, moldability and curing characteristics may be poor.

Next, as long as the curing agent is a compound having two or more functional groups which react with an epoxy group in one minute, the molecular structure and molecular weight are not particularly limited, and trimellitic anhydride, tetrahydrophthalic anhydride and the like are used. Acid anhydrides such as acids, amine-based cured products, phenol novolak resins, resole phenol resins, triphenol alkane resins, polyfunctional phenol resins, dicyclopentadiene phenol resins, naphthalene ring-containing phenol resins, phenol aralkyl resins And the like. Of these, a naphthalene ring-containing phenol resin and a phenol aralkyl resin are preferably used.

Examples of the naphthalene ring-containing phenol resin and phenol aralkyl resin include the following compounds.

[0018]

Embedded image (However, R ¹ represents a hydrogen atom, a halogen atom such as chlorine or bromine or an alkyl group having 1 to 5 carbon atoms, m is an integer of 0 to 3, k and g are integers of 0 or 1 or more, and p is 1 Is an integer greater than or equal to.)

[0019]

Embedded image

Here, the compounding amount of the naphthalene ring-containing phenol resin and the phenol aralkyl resin is 10 to 100% (% by weight, hereinafter the same) of the total phenol resin, preferably 10 to 90%, particularly 20 to 70%. If the amount is less than 10%, low hygroscopicity may not be obtained.

In the present invention, the compounding amount of the curing agent is a normal amount. When a phenol resin is used as the curing agent, the amount of the epoxy group (a) and the amount of the phenolic hydroxyl group (b) in the total epoxy resin are used. (A) / (b) =
A compounding ratio in the range of 0.5 to 1.5, particularly 0.8 to 1.2 is preferable. If the compounding ratio is out of the above range, the curability, crack resistance and moisture absorption may be poor.

In the present invention, a curing catalyst can be blended. The curing catalyst is not particularly limited in molecular weight and molecular structure as long as it promotes the reaction between the epoxy resin and the curing agent, and examples thereof include an imidazole compound, an amine-based curing accelerator, and a phosphorus-based compound. It is desirable to use a phosphorus compound in order to obtain an epoxy resin composition having high property. The amount of the curing catalyst is not particularly limited.
It is preferable to use 4 to 3 parts.

As the inorganic filler used in the present invention, 97% or more has a particle size of 25 μm or less and an average particle size of less than 2.5 μm, and has been previously uniformly mixed with an epoxy resin and / or a curing agent. A material containing at least 1% or more of the fine fused silica in the total inorganic filler is used.

Here, as the fine fused silica, 97%
As described above, preferably 98 to 100% has a particle size of 25 μm or less, and an average particle size (for example, as a weight average by X-ray diffraction method) is less than 2.5 μm, preferably 0.1 to 2.4 μm.
m, more preferably about 0.5 to 2.2 μm. If it is outside this range, the fluidity will not be reduced and the occurrence of burrs cannot be suppressed.

In the present invention, the above-mentioned fine fused silica is previously uniformly mixed with an epoxy resin and / or a curing agent.
In this case, it is preferable that in the uniform mixing process, after sufficiently mixing with a mixer or the like, the melt mixing process is performed at 100 to 120 ° C. with a hot roll, a kneader, an extruder or the like.

Further, the above-mentioned treated fine fused silica accounts for at least 1%, usually 1 to 50%, of the total inorganic filler.
%, Preferably 3 to 25%, more preferably 5 to 15%
If the content of the pre-processed fine fused silica is less than 1%, the fluidity is reduced and the generation of burrs cannot be suppressed.

Further, the amount of the fine fused silica is preferably in the range of 1 to 15%, particularly 2 to 7% of the whole composition, from the viewpoint of fluidity and burr generation.

Usually, fine fused silica has a large specific surface area and a small specific gravity, so that it is difficult to uniformly disperse it with other components, especially with resin components such as epoxy resin and phenol resin, by simple blending. There is a simple blend of fine fused silica for this reason, sufficient fluidity, suppression of burr generation, solder reflow resistance may not be obtained in some cases, but fine fused silica subjected to such treatment in the above range The use of the contained inorganic filler solves these problems and makes it possible to obtain an epoxy resin composition which gives a cured product having good fluidity and excellent moldability and solder reflow resistance.

In the present invention, as the inorganic filler other than the above-mentioned fine fused silica, those which are usually blended in an epoxy resin composition can be used. Specific examples include crystalline silica, fused silica, aluminum nitride, silicon nitride, silicon carbide, alumina, boron nitride, titanium oxide, glass fiber, and the like. Among them, fused silica is preferable.

The average particle size and shape of these inorganic fillers are not particularly limited, but those having an average particle size of 3 to 15 μm are preferable, and those having a spherical shape are preferable in order to increase the packing and reduce the stress on the chip surface. used. In order to increase the bonding strength between the resin and the surface of the inorganic filler, it is necessary to use a material which has been subjected to a surface treatment with a coupling agent such as a silane coupling agent or a titanate coupling agent in advance. It is preferable from the viewpoint of improving crack resistance.

The total amount of the inorganic filler including the above-mentioned fine fused silica is not particularly limited, but 100 to 1300 relative to 100 parts of the total amount of the epoxy resin and the curing agent.
Parts, particularly preferably in the range of 200 to 900 parts.

[0032] The composition of the present invention may further contain other various additives, if necessary, as long as the object of the present invention is not adversely affected. Additives are appropriately selected depending on the application, for example, thermoplastic resins, thermoplastic elastomers, organic synthetic rubber, low stress agents such as silicone-based metal salts, waxes such as carnauba wax, fatty acids such as stearic acid and the like. Release agents such as esters and metal salts thereof; pigments such as carbon black, cobalt blue and red iron oxide; flame retardants such as antimony oxide and halogen compounds; silane coupling agents such as glycidoxypropyltrimethoxysilane; alkyl titanates One or two or more kinds of surface treatment agents, antioxidants, and other additives can be blended.

As a general method for preparing the epoxy resin composition of the present invention as a molding material, the above essential components and other additives are blended in a predetermined composition ratio, and this is thoroughly mixed with a mixer or the like. After that, a melt-mixing treatment is performed by a hot roll, a kneader, an extruder, or the like, and then the mixture is solidified by cooling and pulverized to an appropriate size to obtain a molding material. By using the molding material thus obtained for sealing and coating electronic components or electric components such as semiconductor devices, it is possible to impart excellent reliability under high temperature and high humidity.

The semiconductor device of the present invention can be easily manufactured by sealing a semiconductor element using the above-mentioned sealing resin composition. Here, as a semiconductor element for sealing, for example, an integrated circuit, an arithmetic circuit, a transistor,
Although a thyristor, a diode, etc. are mentioned, it is not particularly limited. The most common method of sealing is
A transfer molding method is exemplified. In this case, the molding temperature of the epoxy resin composition is 30 to 1 at 150 to 180 ° C.
Post cure at 150-180 ° C for 2-1 for 80 seconds
It is desirable to carry out for 6 hours.

It is preferable that the epoxy resin composition is post-cured by further heating after molding. Here, the post-curing is desirably performed under a heating condition of 150 ° C. or more.

[0036]

EFFECT OF THE INVENTION The epoxy resin composition of the present invention has good moldability such as fluidity and suppression of burr generation,
When a cured product with low moisture absorption and excellent reflow resistance is given, and a package of IC, LSI, transistor, etc. is sealed with the cured product of this epoxy resin composition, a highly reliable semiconductor product with excellent moldability is produced. It can be manufactured with good performance.

[0037]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. All parts in each example are parts by weight.

Examples 1 to 6, Comparative Examples 1 to 3 Epoxy resins, phenolic resins and fine fused silica shown in Table 1 were used in the proportions shown in Table 2, and premixed by the following method (1). ) Or (2), and 1 part of triphenylphosphine, 10 parts of antimony trioxide as a curing catalyst,
1.2 parts of carnauba wax, 1.5 parts of γ-glycidoxypropyltrimethoxysilane, 1 part of carbon black,
400 parts of fused spherical silica (I), 400 parts of fused spherical silica (II), and 80 parts of fused spherical silica (III) shown below
Parts (however, the respective silicas (I) to (III) are reduced in an equal ratio according to the amount of the fine fused silica added, and the total amount of the inorganic filler (that is, the total amount of the fine fused silica and the fused spherical silica) is reduced). (The same 880 parts) was uniformly melt-mixed with two hot rolls, cooled and pulverized to obtain an epoxy resin composition (Examples 1 to 6).

Further, the following components were mixed by a usual method without performing the following premixing, and epoxy resin compositions having the compositions shown in Table 2 (Comparative Examples 1 to 3) were obtained.

[0040]

[Table 1]

The fine fused silica Silica A: a specific surface area of 6.3 m ² / g, average particle size 0.5μ
m Content of particles 99% or less with a particle size of 25 μm or less Silica B: specific surface area 33 m ² / g, average particle size 2.1 μm Content of particles 98% or less with a particle size of 25 μm or less Silica C: specific surface area 5.5 m ² / g, average Particle size 2.0μ
m Spherical silica having a particle content of 97% fused spherical silica having a particle diameter of 25 μm or less (I) Spherical silica having a specific surface area of 1.4 m ² / g, an average particle diameter of 15 μm (II) having a specific surface area of 2.5 m ² / g and an average particle diameter of 10 μm Spherical silica (III) Specific surface area 10 m ² / g, average particle size 1.0 μm
Spherical silica premixing method (1): An epoxy resin, a phenolic resin and the above-mentioned fine fused silica are melt-mixed at 110 to 120 ° C. for 5 to 15 minutes, cooled and pulverized. Method (2): A phenol resin and the above-mentioned fine fused silica are mixed in 1
Melt and mix at 10 to 120 ° C for 5 to 15 minutes, pulverize after cooling.

The following tests were conducted on the obtained composition and its cured product. Table 2 shows the results. (A) Spiral flow 175 ° C, 70k using a mold conforming to EMMI standard
g / cm ² . (B) Melt viscosity Using a Koka type flow tester manufactured by Shimadzu Corporation, the flow rate was measured at a nozzle size of 1 mm × length of 10 mm, a load of 10 kg, a sample amount of 3 g, and a temperature of 175 ° C.
The lowest melt viscosity was determined. (C) Flexural strength and flexural modulus 180 ° C, 70 kg / cm according to JIS-K6911
^2. A bending test piece of 10 × 4 × 100 mm was molded under the condition of a molding time of 2 minutes, and was subjected to post-curing at 180 ° C. for 4 hours. (D) Linear expansion coefficient, glass transition temperature Using a test piece having a diameter of 4 mm and a length of 15 mm, the value when the temperature was raised at a rate of 5 ° C. per minute by the TMA method was measured. (E) Adhesiveness A cylindrical molded product having a diameter of 15 mm and a height of 5 mm was molded on a 42 alloy plate under the conditions of 175 ° C., 70 kg / cm ² and a molding time of 2 minutes, and post-cured at 180 ° C. for 4 hours. The peeling amount between the molded product and the 42 alloy plate was measured with a gauge. (F) Solder crack resistance after moisture absorption (reflow resistance) A silicone chip having a size of 7 × 7 × 0.4 mm was used for 10
It was adhered to a lead frame for QFP (42 alloy) having a size of × 14 × 1.4 mm, and the epoxy resin composition was molded thereon under molding conditions of 175 ° C., 70 kg / cm ² , and a molding time of 2 minutes. Post-cured for 4 hours. This was left in an atmosphere of 85 ° C./85% RH for 48 hours and 72 hours, then immersed in a 240 ° C. solder bath for 30 seconds, and the number of package cracks / total number was measured. (G) Moisture resistance A 4MRAM chip was adhered to a 20-pin SOJ frame, and an epoxy resin composition was added thereto at molding conditions of 175 ° C and 7
0 kg / cm ² , molded in 2 minutes, 180 ° C
Time post cure. This is 121 ° C / 100% R
After leaving in a H atmosphere for 24 hours to absorb moisture,
Immersion in a solder bath for 10 seconds, and further 121 ° C / 100% R
The number / total number of Al wiring disconnections when left in an H atmosphere for 300 hours was measured. (H) Water absorption rate A disk having a diameter of 50 mm and a thickness of 2 mm, which was molded under the conditions of a molding time of 175 ° C., 70 kg / cm ² and a molding time of 2 minutes, and post-cured at 180 ° C. for 4 hours, was subjected to 121 ° C./100% R.
It was left in an atmosphere of H for 24 hours, and the water absorption was measured. (Re) Burr characteristics 175 ° C, 70k using a mold conforming to the EMMI standard
The burr length at a slit thickness of 30 μm was measured under the condition of g / cm ² .

From the results shown in Table 2, it can be seen that the epoxy resin composition of the present invention gives a cured product having good moldability such as fluidity and suppression of burr generation, low moisture absorption and excellent reflow resistance. It has been confirmed that a highly reliable semiconductor device can be obtained by sealing the object.

[0044]

[Table 2]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hidefumi Nakayama 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Toshio Shiohara Matsuida-machi, Usui-gun, Gunma Prefecture Hitomi 1-10, Shin-Etsu Chemical Co., Ltd.

Claims (3)

[Claims] 1. An epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler, wherein at least 97% by weight of the inorganic filler has a particle size of 25 μm or less and an average particle size of less than 2.5 μm. An epoxy resin composition characterized in that it contains at least 1% by weight or more of finely divided silica previously uniformly mixed with an epoxy resin and / or a curing agent in the entire inorganic filler. 2. An epoxy resin represented by the following general formula (1):
The epoxy resin shown is used in an amount of 20% by weight or more.
The epoxy resin composition according to the above. Embedded image(Where R Is a hydrogen atom, a halogen atom or a carbon atom 1
And q is an integer of 0-5. ) 3. A semiconductor device sealed with a cured product of the epoxy resin composition according to claim 1.