JPH0952941A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition containing a specific epoxy resin and a curing agent, having excellent curing characteristics and dielectric characteristics, low water-absorptivity, high glass-transition temperature, low linear expansion coefficient and excellent stress characteristics and suitable as a sealing material for semiconductor device, etc. SOLUTION: The objective composition is produced by compounding (A) a resin of formula I [R<1> and R<2> are each H or a 1-4C alkyl, R<3> is a group of formula II(Ra) or group of formula III(Rb) (R<7> is H, CH3 or CF3 ); (n) is 0-10] with (B) a compound of formula IV [R<4> and R<5> are each H, F, a 1-4C alkyl or CF3 ; R<6> is CH2 , C(CH3 )2 , CH(CH3 ), C(CF3 )2 , O, S, Ra, Rb or group of formula V] or its oligomer as a curing agent. The amount of the cyanate group of the component B is preferably 0.3-8mol based on 1mol of the epoxy group of the component A.

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 is preferably used as an encapsulant for semiconductor elements and the like. More specifically, it has good curing characteristics, excellent dielectric characteristics, and water absorption properties. The present invention relates to an epoxy resin composition which gives a cured product having a low glass transition temperature and a high glass transition temperature, and a semiconductor device encapsulated with the cured product.

[0002]

2. Description of the Related Art With the recent increase in the speed of semiconductor elements, the demands on the electrical characteristics of the encapsulating resin have become strict, and the development of encapsulating materials for semiconductor elements, which are particularly excellent in dielectric characteristics, has been strongly developed. Is desired. Therefore, as a method of lowering the dielectric constant of the sealing material, a cyanate ester compound alone or in a mixed system (for example, US Pat.
745,215, JP-A-3-17126, and JP-A-3-17126.
No. 221355), a combination system of a cyanate ester compound and an epoxy resin (for example, 37th Inte).
national SAMPLE Symposiu
m, March 9-12, 1992, 300-30.
1), or various methods using a fluorine-modified polyimide resin or the like have been proposed.

However, the combined use of the cyanate ester compound and the epoxy resin has a lower dielectric constant than that obtained by curing the epoxy resin alone, but the epoxy resin used is an epibis type which is brominated. Therefore, there is a drawback that the water absorption rate increases and dielectric loss occurs. Therefore, it is necessary to reduce the dielectric loss tangent, but no consideration has been given to this point and sufficient dielectric properties have not been obtained.

On the other hand, recently, an epoxy resin composition using a cyanate ester compound and an epoxy resin or a phenol-modified resin has been proposed (JP-A-6-2566).
No. 25). Since this composition gives a cured product having a low water absorption and a high glass transition temperature, it has improved solder reflow resistance, but no improvement in dielectric properties has been studied.

The present invention has been made in view of the above circumstances and has excellent curing characteristics, excellent dielectric characteristics, low water absorption, high glass transition temperature, and high reliability. It is an object of the present invention to provide an epoxy resin composition that gives a cured product suitable as a material and the like, and a semiconductor device sealed with this cured product.

[0006]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of extensive studies conducted by the present inventor to achieve the above object, the epoxy resin represented by the following general formula (1) and the following general formula (1) The epoxy resin composition comprising the cyanate ester compound represented by 2) or its oligomer has good curing characteristics, and the cured product has excellent dielectric characteristics,
It has been found that it has a low water absorption and a high glass transition temperature, and thus is suitable as a sealing material for semiconductor elements and the like which requires high reliability.

[0007]

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That is, when the epoxy resin of the above formula (1) is used in combination with the cyanate ester compound of the above formula (2) or its oligomer as a curing agent, the curing property is good, and the cured product has excellent dielectric properties. Is equipped with
It has low water absorption and high glass transition temperature, which are suitable properties for semiconductor element encapsulants. By encapsulating with this, we have found that a highly reliable semiconductor device can be obtained. It was the invention.

Therefore, the present invention provides (A) the above general formula (1)
And an epoxy resin composition comprising (B) a cyanate ester compound represented by the general formula (2) or an oligomer thereof, and a cured product of the composition. The semiconductor device is provided.

The present invention will be described in more detail below. In the epoxy resin composition of the present invention, the component (A) used as the epoxy resin is represented by the following general formula (1).

[0011]

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Such an epoxy resin is an epoxy resin having a cyclo ring as a skeleton such as dicyclopentadiene, and an epoxy resin having a benzene ring as a skeleton, and representative examples thereof include the following.

[0013]

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[0014]

[Chemical 6]

In this case, the epoxy resin preferably has a monomer content of 90% (wt%, the same applies hereinafter) or more, and particularly 95% or more. If the amount of the monomer component is less than 90%, the resin viscosity becomes high and the viscosity of the composition becomes high, which may result in poor workability. Further, the viscosity of the epoxy resin of the present invention at 150 ° C. is preferably 0.1 to 15 poises, particularly 0.3 to 12 poises. Further, the epoxy equivalent is 100 to 100.
It is preferably 0, particularly 200 to 500.

The epoxy resin used is preferably of high purity in order to be used as a sealing material for semiconductor elements, etc., which is required to have high reliability. Alkali metal etc. is 20ppm or less, more preferably 10p or less when extracted at 120 ° C and 2 atm.
It is preferably pm or less. When the halogen element and the alkali metal are more than 20 ppm, the humidity resistance of the semiconductor device sealed with the composition of the present invention using the halogen element may deteriorate. Furthermore, the hydrolyzable chlorine bound to the resin is 1500 ppm or less, more preferably 1
It is preferably 000 ppm or less.

The composition of the present invention can be used in combination with other epoxy resins in addition to the above-mentioned epoxy resins within a range that does not affect the dielectric properties. Typical of such epoxy resins are epoxy resins having at least two epoxy groups in one molecule, and specifically, bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol. Glycidyl ether type epoxy resin such as novolac type epoxy resin, allylphenol novolac type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, polyfunctional epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, phenol aralkyl type Examples thereof include epoxy resins, heterocyclic epoxy resins, halogenated epoxy resins and the like. In addition, it is preferable that these resins also have high purity, and the halogen element, the alkali metal, and the like in the resin are within the above-described ranges.

The component (B) is a cyanate compound (that is, a cyanate ester compound) represented by the following general formula (2) and / or an oligomer thereof, and acts as a curing agent for the component (A).

[0019]

[Chemical 7]

Here, the cyanate ester compound has two or more cyanate groups in one molecule. Specifically, it is a cyanate ester of a polyaromatic divalent phenol such as bis (3,5). -Dimethyl-4-cyanatephenyl) methane, bis (4-cyanatephenyl) methane, bis (3-methyl-4-cyanatephenyl) methane, bis (3-ethyl-4-cyanatephenyl) methane, bis (4-cyanate) Phenyl) -1,1
-Ethane, bis (4-cyanatephenyl) -2,2-
Propane, di (4-cyanatephenyl) ether, di (4-cyanatephenyl) thioether, 4,4-
{1,3-phenylenebis (1-methylethylidene)}
Bisphenyl cyanate, 4,4-dicyanate-diphenyl, 2,2-bis (4-cyanatephenyl)-
1,1,1,3,3,3-hexafluoropropane, 3
Cyanate esters of divalent phenols such as Tris (4
-Cyanatephenyl) -1,1,1-ethane, bis (3,5-dimethyl-4-cyanatephenyl) -4-
Cyanate phenyl-1,1,1-ethane, polycyanate ester of polyhydric phenol, such as phenol novolac type cyanate ester and cresol novolac type cyanate ester.

The above cyanate ester compound can be appropriately selected according to the application from compounds having a wide range of properties from its solid structure having a softening point of 106 ° C. to its liquid state at room temperature due to its structure. For example, it is preferable to use a liquid compound at room temperature when producing a liquid epoxy resin composition, and to select a solid compound when used in transfer molding. In particular, when the above cyanate ester compound is compounded, it is possible to oligomerize the cyanate ester compound in advance (usually to form a cyclic trimer) and then to react it with an epoxy resin to lower the dielectric constant. It is suitable for exerting the effect.

The cyanate ester compound is required to have a high purity like the above epoxy resin. Particularly, the halogen element and the alkali metal in the cyanate ester compound are extracted at 120 ° C. and 2 atm to 20 p.
It is suitable that it is pm or less, and more preferably 10 ppm or less. In addition, chlorine bound to the compound is 150
It is preferably 0 ppm or less, more preferably 1000 ppm or less.

The mixing ratio of the above epoxy resin to the cyanate ester compound of the above formula (2) is 1 mol of epoxy groups contained in all the epoxy resins in the composition, especially in the epoxy resin of the above formula (1). Cyanate group of the cyanate ester compound is 0.3
It is preferable to blend in a proportion of ˜8.0 mol, especially 0.8˜2.0 mol. If the amount of cyanate groups is less than 0.3 mol or more than 8.0 mol, sufficient curing characteristics may not be obtained.

A curing catalyst may be further added to the epoxy resin composition of the present invention. This is used to accelerate the reaction between the epoxy resin and the cyanate ester compound, and specifically, it is disclosed in JP-A-64-4352.
It is preferable to use a single system of a metal chelate compound such as copper acetylacetonate or cobalt acetylacetonate described in JP-A No. 7, or a combined system with an alkylphenol. In this case, the compounding amount of the curing catalyst is 0.01 to 5 parts by weight, particularly 0.05 to 5 parts by weight in the case of a metal chelate compound, based on 100 parts by weight of the total amount of the epoxy resin and the cyanate ester compound in the composition. The amount of nonylphenol is preferably 0.5 to 8 parts by weight, more preferably 1 to 4 parts by weight. If the amount of the curing catalyst is less than the above range, it may not be possible to obtain a sufficiently cured product.
(Glass transition temperature) becomes low, which may result in poor water absorption.

The composition of the present invention may be blended with an inorganic filler in order to reduce the expansion coefficient and improve the thermal conductivity. In this case, the inorganic filler may be an epoxy resin composition. Can be appropriately selected depending on the use of, for example, crystalline silica, fused silica, ultrafine silica typified by aerosil, alumina, silicon nitride, aluminum nitride, boron nitride, magnesia, calcium silicate, etc. Typical examples of the conductive powder include gold powder, silver powder, aluminum powder, copper powder, and nickel powder. However, since fused silica, alumina and the like have inferior dielectric properties as compared with the composition of the present invention, sufficient consideration must be given to the amount of addition when these are added and mixed.

The shape of the powder of the above-mentioned inorganic filler is not particularly limited, and any of crushed angular particles, spherical particles, scaly particles, and the like can be used depending on the application. Moreover, you may mix and use each. Regarding the particle size distribution of these inorganic fillers, the maximum particle size is 100 μm or less, particularly 50 μm or less, and the average particle size is 1 to 1.
It is preferably 30 microns, especially 3 to 20 microns. If the maximum particle size is larger than 100 μm, not only is it difficult to fill the minute voids, but there is a possibility that the tip of a fine needle may be blocked when a dispenser is used. If the average particle size is less than 1 micron, the particle size becomes too fine and the viscosity tends to increase. On the other hand, if it is larger than 30 microns, the amount of fine powder decreases and the viscosity increases. Therefore, powder having an average particle size of 5 to 30 μm is suitable as the powder having a wide particle size distribution and easy to be most closely packed.

It is preferable that these inorganic fillers have chlorine ions of 10 ppm or less and sodium ions of 10 ppm or less as impurities extracted under the extraction conditions of 120 g at 2.1 atm and 5 g of sample / 50 g of water. If the chlorine ion and the sodium ion are more than 10 ppm, the moisture resistance of the semiconductor device encapsulated with the composition of the present invention using the same may deteriorate.

The blending amount of the inorganic filler is 50 to 95% by weight, preferably 60 to 95% by weight, based on the whole composition.
More preferably, it is 70 to 90% by weight.

Further, it is possible to add an organic resin powder such as polystyrene or silicone in addition to the inorganic filler. In this case, the particle size and shape of the organic resin powder can be the same as those of the inorganic filler.

For the purpose of decreasing the viscosity, the composition of the present invention contains n-butyl glycidyl ether, phenyl glycidyl ether, styrene oxide, t-butyl phenyl glycidyl ether, dicyclopentadiene diepoxide, and 1 Diluents such as 4,4-diglycidoxybutane and 1,6-diglycidoxyhexane can be added. Also, if necessary,
Various additives can be blended depending on the application. For example, a silane coupling agent, a titanium-based coupling agent, a coupling agent such as an aluminum-based coupling agent, a coloring agent such as carbon black, a nonionic surfactant, a fluorine-based surfactant, a wetting improver such as silicone oil, or the like. An antifoaming agent or the like can be added depending on the case.

The method for producing the composition of the present invention is not particularly limited, and a known production method can be employed. For example, an epoxy resin and a cyanate ester compound or an oligomer thereof may be heat treated at the same time or separately as necessary. While adding, stir, dissolve, mix, and disperse. In some cases, the desired epoxy resin composition can be obtained by adding an inorganic filler or the like to these mixtures and mixing, stirring, and dispersing them. At this time, devices for mixing, stirring, dispersing, etc. are not particularly limited, and a reiki machine equipped with a stirring, heating device, a three-roll, a ball mill, a planetary mixer, etc. can be used, and these devices are used in appropriate combination. You may.

The composition of the present invention has excellent electrostatic properties, gives a cured product having low water absorption and a high glass transition temperature.
It can be effectively used for manufacturing semiconductor devices such as LSIs, transistors, thyristors, diodes, etc., and for manufacturing printed circuit boards. Specifically, flip chip sealing, tape automated bonding (TAB), chip on board (COB) semiconductor encapsulation, hybrid IC
It is particularly effective as a spot sealant, an exterior sealant, a liquid crystal adhesive, a ceramic package adhesive, and the like, and can also be suitably used as an exterior material, an adhesive, and a sealant in various industrial fields.

When the semiconductor device is sealed,
It can be carried out by adopting conventionally used molding methods such as transfer molding, injection molding, and casting method. In this case, the molding temperature of the epoxy resin composition is preferably 175 to 200 ° C. for 4 to 8 hours.

[0034]

The epoxy resin composition of the present invention provides a cured product having excellent curing properties and dielectric properties and low water absorption, a low expansion coefficient, and excellent stress properties.
It is suitable as a sealing material for semiconductor elements.

[0035]

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 and Comparative Examples] Compounding composition shown in Table 1 (cyanate ester compound and epoxy resin are equivalent)
Melt-mix at 100 ° C beforehand according to
After preheating for 1 hour at 200 ° C, post-curing for 4 hours
The epoxy resin compositions of Examples 1-5 and Comparative Examples 1-3 were produced.

Next, the obtained epoxy resin composition was subjected to gelling time, glass transition temperature / expansion coefficient, mechanical strength (flexural strength, flexural modulus), water absorption rate by the following methods.
The coefficient of linear expansion was measured. The results are also shown in Table 1. The resin composition was placed on a hot plate having a gelation time of 175 ° C., and the time until the fluidity disappeared was measured while stirring with a spatula. The resin composition was poured into a mold having a glass transition temperature / expansion coefficient of 4 × 4 × 15 mm, and after defoaming, a test piece heat-cured at 120 ° C. for 1 hour and 175 ° C. for 2 hours was used. It was measured by raising the temperature at 5 ° C. per minute with a dilatometer. The expansion coefficient is a value below the glass transition temperature. Mechanical strength (flexural strength, flexural modulus) After pouring the resin composition into a mold having a size of 10 × 100 × 4 mm and defoaming, 120 ° C. for 1 hour, and further 175 ° C.
JIS-
The flexural strength and flexural modulus were measured according to K-6911. Water absorption rate The cured product was evaluated by the water absorption rate when it was left in an atmosphere of 85 ° C and 85% RH for 48 hours.

[0038]

[Table 1] * 1 Bis (3,5-dimethyl-4-cyanatephenyl) methane * 2 * 1 30% cyclic trimer oligomer and 70% by weight
Mixture of monomers * 3 Bis (4-cyanatephenyl) -1,1-ethane * 4 Biphenyl type epoxy resin made by Yuka Shell * 5 Nippon Kayaku o-cresol novolac type epoxy resin * 6 EXA-7200 (Dainippon Ink Chemical Industry Co., Ltd.
* 7 EXA-7200H (manufactured by Dainippon Ink and Chemicals, Inc.) * 8 ESLV-90CR (manufactured by Nippon Steel Chemical Co., Ltd.) * 9 Curing catalyst is cobalt acetylacetonate according to JP-A-64-43527. / Nonylphenol: A solution of 1/10 was prepared in advance and used in 2.2 parts by weight based on 100 parts by weight of the resin component.

From the results shown in Table 1, the cured product obtained by curing the epoxy resin composition of the present invention has a short gel time, a low dielectric constant and a low dielectric loss tangent, and a low water absorption rate. It was confirmed that the glass has a high glass transition temperature, a low linear expansion coefficient, excellent stress characteristics, and good bending strength and bending elastic modulus.

Claims (4)

[Claims] 1. An epoxy resin represented by the following general formula (1): (B) a cyanate ester compound represented by the following general formula (2) or an oligomer thereof, and An epoxy resin composition comprising: 2. The epoxy resin according to claim 1, wherein the cyanate group of the cyanate ester compound of the component (B) is blended in a proportion of 0.3 to 8 mol with respect to 1 mol of the epoxy group of the epoxy resin of the component (A). Composition. 3. The method according to claim 1, wherein an inorganic filler is blended.
The epoxy resin composition according to the above. 4. A semiconductor device encapsulated with a cured product of the epoxy resin composition according to claim 1, 2, or 3.