JP3309661B2 - Epoxy resin composition and semiconductor device - Google Patents

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 suitably used as a sealing material for semiconductor devices, and more specifically, has good curing properties, excellent dielectric properties, and water absorption. 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 sealed with the cured product.

[0002]

2. Description of the Related Art With the recent increase in the speed of semiconductor devices, the demand for electrical characteristics of a sealing resin has become strict. In particular, the development of sealing materials for semiconductor devices having excellent dielectric characteristics has been strongly promoted. Is desired. For this reason, as a method for lowering the dielectric constant of the sealing material, a single or mixed system of cyanate ester compounds (for example, US Pat.
745,215, JP-A-3-17126, and 4
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.

[0003] However, the combined use of the above cyanate ester compound and epoxy resin has a lower dielectric constant than the case where the epoxy resin is cured alone, but it is an epibis type in which the epoxy resin used is brominated. For this reason, there is a drawback that the water absorption increases and dielectric loss occurs. For this reason, it is necessary to reduce the dielectric loss tangent, but this has not been studied at all, and sufficient dielectric characteristics 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). This composition has an improved solder reflow resistance in order to provide a cured product having a low water absorption and a high glass transition temperature. However, no study has been made on improving the dielectric properties.

SUMMARY OF THE INVENTION 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 highly reliable encapsulation for semiconductor devices. It is an object of the present invention to provide an epoxy resin composition that provides a cured product suitable as a material and the like, and a semiconductor device sealed with the cured product.

[0006]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, have found that an epoxy resin represented by the following general formula (1) and an epoxy resin represented by the following general formula (1) The epoxy resin composition comprising the cyanate ester compound or the oligomer thereof represented by 2) has good curing properties, and the cured product has excellent dielectric properties;
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 a semiconductor element 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 a cyanate ester compound of the above formula (2) or an oligomer thereof as a curing agent, the cured product has good curing properties and the cured product has excellent dielectric properties. With
It has low water absorption and high glass transition temperature, which are favorable properties as a sealing material for semiconductor elements, and it is found that a highly reliable semiconductor device can be obtained by sealing with this. This is what led to the invention.

Therefore, the present invention relates to (A) the above-mentioned general formula (1)
And (B) a cyanate ester compound represented by the general formula (2) or an oligomer thereof (provided that R ³ in the formula (1) is a cycloalkyl group as the component (A)). When an epoxy resin which is a pentadienyl group is contained, an epoxy resin obtained by glycidylating a phenolated polybutadiene low (co) polymer obtained by adding a phenol to a low butadiene (co) polymer is not contained. The present invention provides an epoxy resin composition and a semiconductor device sealed with a cured product of the composition.

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

[0011]

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The 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. Representative examples thereof include the following.

[0013]

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[0014]

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In this case, the epoxy resin preferably has a monomer component of at least 90% (% by weight, the same applies hereinafter), particularly preferably at least 95%. If the content of the monomer component is less than 90%, the viscosity of the resin 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 poise, particularly preferably 0.3 to 12 poise. Also, the epoxy equivalent is 100 to 100
It is preferably 0, especially 200 to 500.

The epoxy resin to be used is preferably of high purity in order to be used as a sealing material for a semiconductor element which requires high reliability. Alkali metals and the like are extracted at 120 ° C. and 2 atm under 20 ppm, more preferably 10 ppm or less.
pm or less. When the content of the halogen element and the alkali metal is more than 20 ppm, the moisture resistance of the semiconductor device sealed with the composition of the present invention using the same may be deteriorated. Further, the content of hydrolyzable chlorine bonded to the resin is 1500 ppm or less, more preferably 1 ppm or less.
It is preferably at most 000 ppm.

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. Representative examples of such epoxy resins include epoxy resins having at least two epoxy groups in one molecule. Specifically, bisphenol A type epoxy resin, phenol novolak type epoxy resin, cresol Glycidyl ether type epoxy resin such as novolak type epoxy resin, allylphenol novolak type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, polyfunctional type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, phenol aralkyl type Epoxy resins, heterocyclic epoxy resins, halogenated epoxy resins and the like can be mentioned. In addition, it is preferable that these resins also have high purity, and it is preferable that halogen elements, alkali metals, and the like in the resins be within the above-described ranges.

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

[0019]

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Here, the cyanate ester compound is a compound having two or more cyanate groups in one molecule, and specifically, a cyanate ester of a dihydric phenol having a polyaromatic ring, for example, 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
Trivalent phenol cyanates such as tris (4
-Cyanate phenyl) -1,1,1-ethane, bis (3,5-dimethyl-4-cyanate phenyl) -4-
Cyanate phenyl-1,1,1-ethane, polyhydric phenol polycyanates, such as phenol novolak type cyanate esters and cresol novolak type cyanate esters.

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

The cyanate ester compound is required to be of high purity similarly to the above-mentioned epoxy resin, and in particular, halogen elements and alkali metals in the cyanate ester compound are extracted at 120 ° C. and 2 atm.
pm or less, more preferably 10 ppm or less. Further, the chlorine bound in the compound is 150
It is suitable that it is 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 group contained in all the epoxy resins in the composition, and particularly, in the epoxy resin of the above formula (1). The cyanate group of the cyanate ester compound is in an amount of 0.3 to 1 mol of the epoxy group.
It is preferable to mix them at a ratio of ８8.0 mol, particularly 0.8-2.0 mol. If the amount of the cyanate group is less than 0.3 mol or more than 8.0 mol, sufficient curing properties may not be obtained.

The epoxy resin composition of the present invention may further contain a curing catalyst. This is used to accelerate the reaction between the epoxy resin and the cyanate ester compound, and is specifically described in JP-A-64-4352.
It is preferable to use a single metal chelate compound such as copper acetylacetonate and cobalt acetylacetonate described in JP-A-7, or a combined system with alkylphenol. In this case, the mixing 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 all epoxy resins and cyanate ester compounds in the composition. The amount is preferably 2 parts by weight, and for nonylphenol, it is preferably 0.5 to 8 parts by weight, particularly preferably 1 to 4 parts by weight. If the curing catalyst is less than the above range, a sufficient cured product may not be obtained.
(Glass transition temperature) may be low, resulting in poor water absorption.

The composition of the present invention may contain an inorganic filler for reducing the expansion coefficient or improving the thermal conductivity. In this case, the inorganic filler may be an epoxy resin composition. Non-conductive such as ultrafine powder silica represented by crystalline silica, fused silica, aerosil, alumina, silicon nitride, aluminum nitride, boron nitride, magnesia, calcium silicate, etc. Representative examples thereof include conductive powders such as conductive powders, gold powders, silver powders, aluminum powders, copper powders, and nickel powders. However, since fused silica, alumina and the like are inferior in dielectric properties as compared with the composition of the present invention, when adding and mixing them, it is necessary to give sufficient consideration to the added amount.

The shape of the powder of the inorganic filler is not particularly limited, but any one of pulverized, angular, spherical, and scale-like powders can be used depending on the intended use. Moreover, you may mix and use each. As the particle size distribution of these inorganic fillers, the maximum particle size is 100 microns or less, especially 50 microns or less, and the average particle size is 1 to
Preferably 30 microns, especially 3-20 microns. If the maximum particle size is larger than 100 microns, not only is it difficult to fill the fine voids, but also if the dispenser is used, there is a possibility that the tip of the fine needle may be blocked. On the other hand, if the average particle size is smaller 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, on the other hand, the viscosity increases due to the decrease in fine powder. Therefore, as a powder having a wide particle size distribution and which is easy to be closely packed, a powder having an average particle size of 5 to 30 microns is preferable.

These inorganic fillers preferably have a chlorine ion content of 10 ppm or less and a sodium ion content of 10 ppm or less at 120 ° C. and 2.1 atm under the extraction conditions of 5 g of sample / 50 g of water. When the chlorine ion and the sodium ion are more than 10 ppm, the moisture resistance of the semiconductor device sealed with the composition of the present invention using the same may be deteriorated.

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

Further, an organic resin powder such as polystyrene or silicone may be added 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 lowering the viscosity, the composition of the present invention contains conventionally known n-butyl glycidyl ether, phenyl glycidyl ether, styrene oxide, t-butyl phenyl glycidyl ether, dicyclopentadiene diepoxide, Diluents such as 1,4-diglycidoxybutane, 1,6-diglycidoxyhexane can be added. Also, if necessary, its purpose,
Various additives can be blended according to the use and the like. 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 enhancer such as silicone oil, An antifoaming agent or the like can be added in some cases.

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 subjected to heat treatment simultaneously or separately, if necessary. While adding, stirring, dissolving, mixing and dispersing. In some cases, the desired epoxy resin composition can be obtained by adding, mixing, stirring, and dispersing an inorganic filler or the like to these mixtures. At this time, the apparatus for mixing, stirring, dispersing, and the like is not particularly limited, and a raikai machine equipped with a stirring and heating apparatus, a three-roll, ball mill, a planetary mixer, or the like can be used. May be.

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

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

[0034]

The epoxy resin composition of the present invention is excellent in curing properties and dielectric properties and gives a cured product having low water absorption, and has 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] Compositions shown in Table 1 (equivalent amounts of cyanate ester compound and epoxy resin)
Is melt-mixed in advance at 100 ° C.
After preheating for 1 hour, post-curing at 200 ° C for 4 hours
The epoxy resin compositions of Examples 1 to 5 and Comparative Examples 1 to 3 were produced.

Next, the obtained epoxy resin composition was subjected to gelation time, glass transition temperature / expansion coefficient, mechanical strength (flexural strength, flexural modulus), water absorption,
The linear expansion coefficient was measured. The results are also shown in Table 1. The resin composition was placed on a hot plate having a gel time of 175 ° C., and the time until the fluidity disappeared was measured while stirring with a spatula. After pouring the resin composition into a mold having a glass transition temperature and an expansion coefficient of 4 × 4 × 15 mm, and defoaming, using a test piece that is heat-cured at 120 ° C. for 1 hour and at 175 ° C. for 2 hours, The measurement was carried out by raising the temperature at 5 ° C. per minute using a dilatometer. The expansion coefficient is a value below the glass transition temperature. Mechanical strength (flexural strength, flexural modulus) The resin composition was poured into a mold having a size of 10 × 100 × 4 mm, and after defoaming, was further heated at 120 ° C. for 1 hour, and further at 175 ° C.
JIS-
Flexural strength and flexural modulus were measured according to K-6911. The water absorption was evaluated by the water absorption when the cured product 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 epoxy resin manufactured by Yuka Shell * 5 o-cresol novolac epoxy resin manufactured by Nippon Kayaku * 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 The curing catalyst is cobalt acetylacetonate according to JP-A-64-43527. / Nonylphenol: A 1/10 solution was prepared in advance and used in an amount of 2.2 parts by weight based on 100 parts by weight of the resin component.

From the results in Table 1, it can be seen that the cured product obtained by curing the epoxy resin composition of the present invention requires a short gelation time, has a low dielectric constant and dielectric loss tangent, has a low water absorption, It was confirmed that at a high glass transition temperature, the coefficient of linear expansion was low, the stress characteristics were excellent, and the flexural strength and flexural modulus were good.

Continuation of the front page (56) References JP-A-53-75299 (JP, A) JP-A-9-12682 (JP, A) JP-A 8-176273 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) C08L 63/00-63/10 C08L 79/04-79/06 H01L 23/29

Claims (4)

(57) [Claims] (A) 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 (Provided that the component (A) has the formula (1)
When the epoxy resin in which R ³ is a cyclopentadienyl group is contained, a phenolated polybutadiene low (co) polymer obtained by adding phenols to a butadiene low (co) polymer is glycidylated. Epoxy resin composition). 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 ratio of 0.3 to 8 mol per 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.