JPH065743A - Liquid epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To seal semiconductor with plastic having high filling properties and small thermal expansion coefficient. CONSTITUTION:Liquid epoxy resin composition for sealing semiconductor so contains amorphous spherical silica having 90wt.% or more of particles having 40mum or less of particle size in a particle size distribution of 1 to less than 15mum of mean particle size and 10m<2>/g or less of a specific surface area as to be 40 to less than 90wt.% of total amount of the epoxy resin, curing agent and the silica.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid epoxy resin composition for semiconductor encapsulation, more specifically, COB (chi)
p on board) or TAB (tape au)
The present invention relates to a liquid epoxy resin composition for semiconductor encapsulation which is useful for plastic encapsulation of semiconductors for tomated bonding.

[0002]

2. Description of the Related Art With the advance of technology in recent years, semiconductors are now highly integrated such as LSI and VLSI. This highly integrated semiconductor device is sealed with a synthetic resin composition to protect it from the external environment. Resin encapsulating materials for encapsulating such semiconductors can be roughly classified into two types: solid encapsulating materials for transfer molding and liquid encapsulating materials for drop molding. Reliable solid encapsulating materials are mainly used for industrial applications, and liquid encapsulating materials are used for some consumer devices such as calculators, watches, and cameras. As the liquid encapsulating material, for example, there are many bisphenol A type epoxy resins, acid anhydride as a curing agent, imidazole as a curing catalyst, and a pigment, a solvent, and the like. The focus was on what to do. For example, it has been attempted to improve the film-forming property by adding fumed silica or the like to the above liquid encapsulating material or adding a plurality of solvents having different boiling points. However, recently, high reliability of the semiconductor has been required for the liquid sealing material. In order to respond to this, attempts have been made to divert silica for solid encapsulating materials to liquid encapsulating materials, but since this method is originally a technique for solid encapsulating materials, various problems occur. is doing. For example, the filling property of the resin composition into the wire portion or bump portion of the COB or the bump portion or slit portion of the TAB is lowered, and as a result, the reliability of the semiconductor is lowered.

The best way to improve the reliability of the semiconductor is to make the thermal expansion coefficient of the sealing material as close as possible to that of the semiconductor, that is, to make the thermal expansion coefficient of the sealing material as small as possible. At present, the best method is to highly fill amorphous silica. In the case of silica for a solid encapsulating material, spherical silica and crushed silica having a wide particle size distribution are used alone or in combination in order to enable high filling. However, even if this silica for a solid encapsulating material is diverted to a liquid encapsulating material, the coating property and the filling property are inferior, and therefore the semiconductor reliability is not sufficient.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and relates to a liquid epoxy resin composition for semiconductor encapsulation which improves the reliability of the semiconductor.

[0005]

That is, the present invention has an average particle size of 1 μm or more and less than 15 μm and a particle size distribution of 40 μm.
90% by weight or more of particles having the following particle diameters and a specific surface area of 1
Liquid epoxy resin for semiconductor encapsulation, containing 0 m ² / g or less of amorphous spherical silica in an amount of 40% by weight or more and less than 90% by weight based on the total amount of the epoxy resin, the curing agent and the amorphous spherical silica. It is a composition.

The silica used in the present invention is amorphous spherical silica. When crushed silica is used as a liquid composition, it has a high viscosity, lacks a high filling property, and has a sharp particle surface, which may cut the semiconductor wiring, which is not preferable. Further, crystalline silica has a large coefficient of thermal expansion as compared with amorphous silica, which is not preferable. The amorphous spherical silica can be produced by, for example, a method of flame-melting high-purity natural quartz powder or high-purity synthetic silica powder with oxygen-propane, oxygen-hydrogen, or the like, or a sol-gel method by an emulsification reaction, or the like. . The thus-produced amorphous spherical silica does not necessarily have to have a true spherical shape, and may have a slightly elliptical spherical body.

The amorphous spherical silica used in the present invention has an average particle diameter of 1 μm or more and less than 15 μm, preferably 2 μm.
It is at least μm and less than 8 μm. Here, the average particle size is expressed by the dimension by the laser diffraction method (D ₅₀ ). When the average particle size of the amorphous spherical silica is less than 1 μm, the viscosity of the liquid epoxy resin composition for semiconductor encapsulation is large and high filling becomes difficult, and when it is 15 μm or more, the epoxy resin composition. It is not preferable because the classification in the interior is quick and the uniform dispersibility is lowered.

The amorphous spherical silica has a particle size distribution of 90% by weight or more of particles having a particle size of 40 μm or less, preferably 95% by weight of particles having a particle size of 24 μm or less.
The above is good. If the amount of particles of 40 μm or less is less than 90% by weight, the wire portion and bump portion of COB, and TA
It is not preferable because the filling property of B into the bump portion and the slit portion is deteriorated.

The specific surface area of the amorphous spherical silica is 1
It is 0 m ² / g or less, preferably 5 m ² / g or less. When the specific surface area exceeds 10 m ² / g, the viscosity of the liquid epoxy resin composition for semiconductor encapsulation becomes high, which is not preferable.

The content of the amorphous spherical silica is 40% by weight based on the total amount of the epoxy resin, the curing agent and the amorphous spherical silica in the liquid epoxy resin composition for semiconductor encapsulation.
It is at least 90% by weight and preferably at least 55% by weight and less than 80% by weight. If the compounding amount of the amorphous spherical silica is less than 40% by weight, the coefficient of linear expansion and water absorption of the liquid epoxy resin composition for semiconductor encapsulation after curing are unfavorably high. On the other hand, if the blending amount is 90% by weight or more, the viscosity of the liquid epoxy resin composition for semiconductor encapsulation increases and the sealing workability deteriorates.

The epoxy resin used in the present invention may be a commonly used epoxy resin, for example, bisphenol A.
Type, bisphenol F type, biphenol type, polyfunctional type epoxy resin and the like, and may be a mixture of two or more kinds thereof. Since the epoxy resin adversely affects the moisture resistance reliability of the semiconductor after encapsulation when the content of ionic impurities is large, it is preferable that the content of ionic impurities such as sodium ions and chlorine ions is as small as possible.

The hardener used in the present invention may be a commonly used one, and examples thereof include polyhydric phenols, aromatic polybasic acids, aromatic polyamines, and the like. For example, phenol novolac, biphenol type novolac and bisphenol. A novolak such as A-type novolac, an acid anhydride such as phthalic anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic anhydride, or an amine such as diaminodiphenylmethane, diaminodiphenylsulfone, or metaphenylenediamine is used.

In the present invention, the liquid epoxy resin composition for semiconductor encapsulation preferably contains a solvent in order to improve the workability of semiconductor encapsulation. As the solvent, a plurality of solvents having different boiling points are mixed, and those having good coatability and film forming property are appropriately used. For example, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, alcohols such as methanol, ethanol, isopropanol, butanol and isobutanol, hydrocarbons such as hexane, heptane, benzene, toluene and xylene, diacetone alcohol and ethylene glycol. Examples thereof include monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether. The content of the solvent in the liquid epoxy resin composition for semiconductor encapsulation is preferably less than 60% by weight, particularly preferably 5% by weight or more and less than 30% by weight. In the absence of solvent, the viscosity of the epoxy resin composition becomes high and the workability is poor, and
When it is 60% by weight or more, the above amorphous spherical silica in the epoxy resin composition is easily separated from the epoxy resin, the curing agent and the solvent, which is not preferable.

In the liquid epoxy resin composition for semiconductor encapsulation of the present invention, in addition to the above-mentioned components, various additives which are usually used, such as tertiary amines and organophosphorus compounds, are used as required. A curing catalyst, a flame retardant, a coloring agent, a silane coupling agent, etc. can be added.

The liquid epoxy resin composition for semiconductor encapsulation of the present invention can be prepared by kneading the above-mentioned components with, for example, a kneader, roll, mixer or the like.

When a semiconductor is encapsulated using the liquid epoxy resin composition of the present invention, it is possible to encapsulate a semiconductor plastic having a high filling property and a small coefficient of thermal expansion. The reliability superior to the solid epoxy resin composition for industrial semiconductor encapsulation can be mentioned. Further, the liquid epoxy resin composition of the present invention enables miniaturization of a semiconductor package, which can promote miniaturization of consumer equipment such as personal computers and VTRs.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following examples and comparative examples, all parts are parts by weight.

[0018]

【Example】

[0019]

Example 1 7 parts each of a bisphenol A type epoxy resin (RE-410 manufactured by Nippon Kayaku Co., Ltd.) and a biphenol type epoxy resin (YX-4000H manufactured by Yuka Shell Co., Ltd.) were used as epoxy resins, and as a curing agent. Phenol novolac (PSM-4261 Gunei Chemical Industry Co., Ltd.)
7 parts), 0.2 parts of triphenylphosphine (manufactured by TPP Kitako Chemical Co., Ltd.) as a curing accelerator, 0.3 parts of carbon (MA-600 manufactured by Mitsubishi Kasei Co., Ltd.) as a pigment, and a silane coupling agent. γ-glycidoxypropyltrimethoxysilane (A-187 Nippon Unicar Co., Ltd.)
0.5 part) and average particle size 2 μm, maximum particle size 15 μm
m, 79 parts of amorphous spherical silica having a specific surface area of 4 m ² / g, and 20 parts of a mixture of methyl ethyl ketone and toluene (mixing ratio 1/1) as a solvent were kneaded with a heating kneader to prepare a liquid epoxy resin composition.

The workability, material properties and reliability of the obtained liquid epoxy resin composition were evaluated. The results are shown in Table 1.

[0021]

Examples 2 to 8 Liquid epoxy resin compositions were prepared in the same manner as in Example 1 except that silica having the average particle size, maximum particle size and specific surface area shown in Table 1 was used as the amorphous spherical silica. It prepared and evaluated variously. The results are shown in Table 1.
Shown in.

[0022]

Example 9 18 parts of bisphenol A type epoxy resin (RE-410 manufactured by Nippon Kayaku Co., Ltd.) and biphenol type epoxy resin (YX-4000H manufactured by Yuka Shell Co., Ltd.) were used as epoxy resins, respectively, and as a curing agent. 18 parts of phenol novolac (PSM-4261 manufactured by Gunei Chemical Industry Co., Ltd.) and 46 parts of amorphous spherical silica having an average particle size of 4 μm, a maximum particle size of 20 μm and a specific surface area of 2 m ² / g shown in Table 1 were used. A liquid epoxy resin composition was prepared and various evaluations were performed in the same manner as in Example 1 except for the above. The results are shown in Table 1.

[0023]

Comparative Example 1 Average particle size 4 μm and maximum particle size 45 shown in Table 1
40 μm of an amorphous silica with a specific surface area of 2 m ² / g
A liquid epoxy resin composition was prepared and various evaluations were performed in the same manner as in Example 1 except that silica containing 15% of particles having a particle size exceeding μm was used. The results are shown in Table 1.

[0024]

Comparative Examples 2 to 4 Liquid epoxy resin compositions were prepared in the same manner as in Example 1 except that silica having average particle diameter, maximum particle diameter and specific surface area shown in Table 1 were used as the amorphous spherical silica. It prepared and evaluated variously. The results are shown in Table 1.
Shown in.

[0025]

[Comparative Example 5] Bisphenol A type epoxy resin (RE-410 manufactured by Nippon Kayaku Co., Ltd.) and biphenol type epoxy resin (YX-4000H manufactured by Yuka Shell Co., Ltd.) were used as the epoxy resin in 23 parts each, and as a curing agent 23 parts of phenol novolac (PSM-4261 manufactured by Gunei Chemical Industry Co., Ltd.) and 31 parts of amorphous spherical silica having an average particle size of 4 μm, a maximum particle size of 20 μm and a specific surface area of 2 m ² / g shown in Table 1 were used. A liquid epoxy resin composition was prepared and various evaluations were performed in the same manner as in Example 1 except for the above. The results are shown in Table 1.

[0026]

Comparative Example 6 Average particle size 4 μm and maximum particle size 20 shown in Table 1
A liquid epoxy resin composition was prepared in the same manner as in Example 1 except that 79 parts of crushed silica having a micrometer and a specific surface area of 2 m ² / g was used, but the workability was poor and sealing was impossible.

[0027]

Comparative Example 7 18 parts of bisphenol A type epoxy resin (RE-410 manufactured by Nippon Kayaku Co., Ltd.) and biphenol type epoxy resin (YX-4000H manufactured by Yuka Shell Co., Ltd.) were used as epoxy resins, respectively, and as a curing agent. Example 1 except that 18 parts of phenol novolac (PSM-4261 manufactured by Gunei Chemical Industry Co., Ltd.) and 46 parts of crushed silica having the same properties as used in Comparative Example 6 were used
A liquid epoxy resin composition was prepared and various evaluations were performed in the same manner as in. The results are shown in Table 1.

[0028]

[Table 1] The evaluation methods in Table 1 are as follows.

Workability Applicability: The application state when the device hole is sealed in TAB is visually observed.

Fillability: In TAB, the filling state of the bump portion is visually observed.

The observation result is displayed as follows.

◎: Very good condition ○: Good condition Δ: Poor condition ×: Very bad condition Material properties α ₁ : Average thermal expansion coefficient of 40 to 80 ° C. Water absorption rate: 121 ° C., 100% humidity Water absorption rate after leaving for 100 hours Reliability T / C: -65 ° C for TAB sealed product equipped with simulated IC
Package cracks are observed after 1000 cycles of heat history from room temperature to 150 ° C.

Number of defects / total number of tests (20) PCT: 121 ° C. for a COB-sealed product equipped with a simulated IC
Observing leak failure after leaving for 1000 hours at 100% humidity.

Number of defectives / total number of tests (20) D ₅₀ : Indicates the average particle size.

[0035]

INDUSTRIAL APPLICABILITY As described above, the liquid epoxy resin composition for semiconductor encapsulation of the present invention enables homogeneous encapsulation of semiconductor plastic having a high filling property and a small coefficient of thermal expansion. Further, the reliability superior to that of the solid epoxy resin composition for semiconductor encapsulation enables miniaturization of semiconductor packages and miniaturization of consumer devices such as personal computers and VTRs.

Claims (1)

[Claims] 1. 90% by weight of particles having an average particle size of 1 μm or more and less than 15 μm and a particle size distribution of 40 μm or less.
A semiconductor characterized by containing 40 wt% or more and less than 90 wt% of amorphous spherical silica having a specific surface area of 10 m ² / g or less with respect to the total amount of the epoxy resin, the curing agent and the amorphous spherical silica. Liquid epoxy resin composition for encapsulation.