JPH04285617A - Resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To obtain the subject composition having high fluidity and excellent moldability and giving little burr in molding by compounding, as essential components, a polymaleimide compound, an allylphenol compound and spherical silica containing a fraction having a specific particle diameter at a specific ratio. CONSTITUTION:The objective composition contains, as essential components, (A) a polymaleimide compound having >=2 maleimide groups (preferably an aromatic polymaleimide such as 1,4-dimaleimido-benzene), (B) an allylphenol compound of formula (X is SO2, CO, etc.) [e.g. 2,2-bis(3-allyl-4-hydroxyphenyl) propane] and (C) spherical silica containing spherical silica particles having an average primary particle diameter of 7-50nm accounting for 0.5-7wt.% of the total silica component. The component C is preferably produced by mixing spherical silica having an average particle diameter of 50nm to 150mum and spherical silica having an average primary particle diameter of 7-50nm.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for encapsulating semiconductors, and more particularly to a resin composition having excellent fluidity and moldability.

0002

BACKGROUND OF THE INVENTION Conventionally, many epoxy resins have been used as thermosetting resins. However, the usage conditions for molded products have become increasingly severe in recent years, and as a result, it has become increasingly difficult for epoxy resins to satisfy the overall properties. Polyimide resin is well known as a resin with higher heat resistance than epoxy resin, but polyimide resin generally has low solubility in organic solvents,
In addition, the melting point or softening temperature is high, and moldability is not necessarily good.

[0003]Resin compositions of polymaleimide resin, which is a thermosetting polyimide resin, and o,o'-diallyl bisphenol A are described in Japanese Patent Publication No. 1983-39242.
For the composition of a bismaleimide compound and a diallyl ether of bisphenol S, see Japanese Patent Publication No. 1983.
Examples of compositions of a bismaleimide compound and an allyl etherified phenol novolak are known, such as No. 3-134099 and Japanese Patent Publication No. 11716/1983. Furthermore, it is known that silica with a low coefficient of thermal expansion is added to plastic encapsulation to reduce thermal stress on the surface of ICs and LSIs, and silica was added to bismaleimide compounds and developed for semiconductor encapsulation. Examples of resin compositions are known, such as Japanese Patent Publication No. 63-230728. However, in these documents, there is no description of the influence of the shape, average particle size, and filling amount of silica on fluidity during molding and moldability.

0004

[Problem to be solved by the invention] Silica with a low coefficient of thermal expansion is necessary for reducing thermal stress in plastic encapsulants, but simply increasing the amount of silica lowers the fluidity during molding, which is not desirable. It is expected that the molding will not be carried out satisfactorily.

[0005]

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the present inventors found that a polymaleimide compound,
The present invention was achieved by discovering that a resin composition with high fluidity and good moldability can be obtained by combining a phenol compound and a plurality of silicas. That is,
The gist of the present invention is as follows:A. A polymaleimide compound having two or more maleimide groups in the molecule represented by the following general formula (2) (where n is an integer of 2 or more, and Y represents a polyvalent residue of 2 or more valences),

[0006]

[Case 2]

B. An allylphenol compound represented by the following general formula (1) (X is C(CH3)2, SO2
, SO, S, O, CO),

000
8]

[Chemical formula 3]

C. The average particle diameter of primary particles is 7 nm or more50
At least 0.5% by weight of spherical silica of nm or less in total silica7
A resin composition for semiconductor encapsulation is characterized in that it contains spherical silica as an essential component, which accounts for less than % by weight.

The details of the present invention will be explained below.

The polymaleimide compound having two or more maleimide groups in the molecule, which is component A used in the present invention, is a polymaleimide compound having two or more maleimide groups in the molecule represented by general formula (2). If so, it is not particularly limited. Here, n is an integer of 2 or more,
Y represents a multivalent residue having a valence of two or more. Y may be aliphatic, aromatic, alicyclic, or heterocyclic as long as it is a divalent or higher polyvalent residue, but aromatic is preferable.

Component A used in the present invention can be easily obtained by reacting a diamine or polyamine with maleic anhydride. The diamine is a compound represented by the general formula (H2N)nY (n is 2, and Y is the same as Y in the general formula (2) and represents a divalent residue). Specifically, the bismaleimide compounds obtained by the reaction of diamine and maleic anhydride include 1,2-dimaleimidoethane, 1,3-
Aliphatic polymaleimides such as dimaleimidopropane, bis(4-maleimidophenyl)methane, bis(3
-ethyl-4-maleimidophenyl)methane, bis(3
-ethyl-4-maleimido-5-methylphenyl)methane, 2,7-dimalimidofluorene, 1,3-dimalimidobenzene, 1,4-dimalimidobenzene, 2,
4-dimalimidotoluene, bis(maleimidophenyl) sulfone, bis(maleimidophenyl) ether, 2
, 2-bis(4-(4-maleimidophenoxy)phenyl)propane, bis(4-(4-maleimidophenoxy)phenyl)sulfone, 1,3-bis(2-(3-maleimidophenyl)propyl)benzene (each Aromatic polymaleimides such as (including isomers), alicyclic polymaleimides such as 1,4-dimaleimidocyclohexane, etc., heterocyclics such as bis(maleimidophenyl)thiophene (including isomers), etc. Examples include polymaleimide. The polymaleimide compound used in the present invention is not particularly limited, but aromatic polymaleimide is preferred from the viewpoint of heat resistance. The polyamine has the general formula (H2N)nY (n is an integer of 3 or more,
Y is the same as Y in general formula (2) and represents a trivalent or higher valent residue). Further, specific examples of the polymaleimide compound obtained by the reaction of a polyamine and maleic anhydride include a maleimide of a polycondensate of aniline or a derivative thereof and formalin.

Examples include adducts obtained by reacting the various polymaleimide compounds obtained as described above with aromatic diamines, aliphatic diamines, etc. so that maleimide functional groups remain. Furthermore, it is also possible to use two or more of these polymaleimide compounds in combination, or to mix the above diamines or polyamines to form maleimide and use it as a mixture of polymaleimide compounds. Monomaleimide can be added within a range that does not impair fluidity or moldability.

In the phenol compound represented by the general formula (1) which is component B of the present invention, X is C(CH3)2
, SO2, SO, S, O, and CO, there is no particular limitation. Specifically, 2,2-bis(3-allyl-4-hydroxyphenyl)propane, bis(3-allyl-4-hydroxyphenyl)sulfone, bis(3-allyl-4-hydroxyphenyl)sulfoxide, bis( 3-Allyl-
Examples include 4-hydroxyphenyl) sulfide, bis(3-allyl-4-hydroxyphenyl) ether, and bis(3-allyl-4-hydroxyphenyl) ketone. Furthermore, it is also possible to use two or more types of these in combination.

Although the reaction proceeds with component A alone without component B, the resulting cured product has a high modulus of elasticity and is extremely brittle. In addition, the maleimide group in component A copolymerizes with vinyl groups, allyl groups, etc. to give a cured product, but the reaction does not proceed much during mixing with component C and other functional agents, and the temperature is higher than the mixing temperature. When molding at high temperatures, it is desirable to react quickly. From this point of view, component B, allylphenol, is essential.

Component C used in the present invention is spherical silica whose primary particles have an average particle diameter of 7 nm or more and 50 nm or less, and accounts for 0.5% or more and 7% or less of the total silica, but the particle size distribution is It is not necessary that there is only one maximum. Silica whose primary particles have an average particle size of 7 to 50 nm is commercially available under the trade name Aerosil. This silica preferably accounts for 0.5% by weight or more and 7% by weight or less of the total silica. If it is less than 0.5% by weight, the filling properties of the composition with the resin are good, but the handling and molding properties are poor, and when insert molding such as semiconductor encapsulation is performed, resin leakage called burr from around the cubitity occurs. occurs significantly. If it exceeds 7% by weight, the fluidity of the composition will decrease. The preferred particle size range of the spherical silica used is 7 nm or more and 150 μm or less. Spherical silica groups with an average particle size exceeding 150 μm are easily separated, making uniform mixing and uniform molding difficult. Spherical silica with a diameter of 7 nm or less increases the specific surface area of the silica and tends to cause aggregation, and the viscosity of the resin composition increases, resulting in a decrease in fluidity. Examples of spherical silica include silica produced by reducing the anisotropy of crystalline silica by flame spraying, etc., and silica synthesized by hydrolyzing alkyl silicate or silicon tetrachloride, but the spherical silica used here is Regardless of the manufacturing method, it is sufficient that the shape is spherical.

The spherical silica used in the present invention is preferably obtained by mixing spherical silica with an average particle size of 50 nm or more and 150 μm or less and spherical silica whose primary particles have an average particle size of 7 nm or more and 50 nm or less. This mixing may be done in advance, or may be done for the first time when kneading with other components. Particularly preferably, the above average particle size is 50
Spherical silica with an average particle size of nm or more and 150 μm or less is 10
Spherical silica of 0 nm or more and 2 μm or less and average particle size of 10 μm
Preferably, the silica is obtained by mixing spherical silica with a size of 100 μm or more.

In the case of semiconductor encapsulation, it is necessary to avoid destroying the memory and causing malfunction. This is said to be caused by radioactive elements such as uranium and thorium, which are α-ray sources, contained in the sealing material, so it is desirable that these elements be contained in a small amount. In the present invention, each of these components is an essential component, and preferably the blending ratio is based on 1 equivalent of the maleimide functional group of the polymaleimide compound (component A) having two or more maleimide groups in the molecule. , the allyl group of the phenol compound (component B) is 0.
Preferably, it is in the range of 5 to 1.5 equivalents. If the amount of allyl group is less than 0.5 equivalent, the molded product becomes brittle and 1
．． When the amount is more than 5 equivalents, heat resistance decreases. Further, it is desirable that the C component occupies 20 to 95% by volume of the entire resin composition, preferably 60 to 90% by volume. If the filling rate is less than 20% by volume, the effect of reducing the coefficient of thermal expansion will be insufficient, and if the filling rate exceeds 95% by volume, it will not be possible to ensure the fluidity necessary for molding.

[0019] By kneading silica that satisfies the conditions of average particle size, shape, and volume ratio of silica with the above-mentioned polymaleimide compound and allylphenol compound, good fluidity and good molding can be achieved. Processability becomes possible. Such a resin composition has a small coefficient of thermal expansion, good heat resistance, high fluidity, and good moldability, and can be used as a resin composition for semiconductor encapsulation. Here, the method of curing the composition of the present invention can be easily achieved by heating from the outside, but by adding a catalyst or curing accelerator, the molding temperature or molding time can be adjusted depending on the molding method, the shape of the molded product, etc. can be controlled. Examples of catalysts and curing accelerators used for this include radical generators such as organic peroxides and azo compounds, organic amine compounds, and organic phosphorus compounds. Specific examples include azoisobutyronitrile, tert-butyl perbenzoate, dicumyl peroxide, benzoyl peroxide, peroxyketal of levulinic acid ester or tributylamine, 4-(N,N-dimethylamino)pyridine, Examples include lutidine, 2-ethyl-4-methylimidazole, and tritolylphosphine.

[0020] Furthermore, inorganic fillers other than silica, reinforcing fibers, etc. can be added to the resin composition of the present invention. Specific examples include alumina powder, mica, titania, zirconia, glass fiber, carbon fiber, aramid fiber,
Examples include boron fiber. Furthermore, if necessary, natural waxes, synthetic waxes, organic fatty acids, internal mold release agents such as organic fatty acid metal salts, halogen compounds, flame retardants such as antimony oxide, coloring agents such as carbon black, etc.
Functionality improving agents such as surface treatment agents such as silane coupling agents and titanium coupling agents, and flexibility imparting agents such as nitrile rubber and silicone resins can be added.

[0021]

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples unless it departs from the gist thereof.

Synthesis Example 100g of bis(4-maleimidophenyl)methane, 27.7g of bis(4-aminophenyl)methane in 200ml
in dimethylformamide (DMF) at 120 °C for 30
The mixture was heated for 1 minute, poured into water, and the resulting precipitate was filtered and dried to obtain 120.2 g of adduct A. The vinyl proton of maleimide was confirmed by nuclear magnetic resonance method.

Example 1 41.7 g of bis(4-maleimidophenyl)methane, 2
, 31.6 g of 2-bis(3-allyl-4-hydroxyphenyl)propane, 29 spherical silica with an average particle size of 18 μm
9 g of spherical silica with an average particle size of 0.9 μm, 117 g of spherical silica with an average particle size of 0.9 μm, and silica with an average primary particle size of 12 nm (AEROSIL 200 manufactured by Nippon Aerosil Co., Ltd.)
(registered trademark)) 4g, γ-glycidoxypropoxytrimethoxysilane 4.2g, butyl levulinate-tert
-butyl peroxyketal 1.5 g, 1,4-bis(
2-(2-(tert-butylperoxy)propyl)
) 0.4g of benzene, 0.7g of carnauba wax 2
A resin composition was obtained by uniformly mixing with this roll. Table 2 shows the fluidity and appearance of burrs of the obtained resin composition.

Example 2 288 g of spherical silica with an average particle size of 18 μm in Example 1
A composition was obtained in the same manner as in Example 1, except that 112 g of spherical silica with an average particle size of 0.9 μm and 20 g of Aerosil 200 were used. Table 2 shows the properties of the obtained resin composition.

Example 3 31.7 g of bis(4-maleimidophenyl)methane, 2
, 13.6 g of 2-bis(3-allyl-4-hydroxyphenyl)propane, 13.6 g of adduct A listed in the synthesis example
A composition was obtained in the same manner as in Example 1, except that 294 g of spherical silica with an average particle size of 18 μm, 114 g of spherical silica with an average particle size of 0.9 μm, and 12 g of Aerosil 200 were used. Table 2 shows the fluidity and appearance of burrs of the obtained resin composition.

Example 4 The spherical silica of Example 1 having an average particle diameter of 0.9 μm was mixed with 44.
I used 9g of spherical silica 69 with an average particle size of 0.3μm.
．． A composition was obtained with the same composition as in Example 1 except that 3 g was added. Table 2 shows the fluidity of the obtained resin composition.

Comparative Example 1 302 g of spherical silica with an average particle size of 18 μm in Example 1
A composition was obtained in the same manner as in Example 1, except that 118 g of spherical silica with an average particle size of 0.9 μm was used and silica with an average primary particle size of 7 to 50 nm was not added. Table 2 shows the properties of the obtained resin composition.

Comparative Example 2 275 g of spherical silica with an average particle size of 18 μm in Example 1
A composition was obtained in the same manner as in Example 1, except that 107 g of spherical silica with an average particle size of 0.9 μm and 38 g of Aerosil 200 were used. Table 2 shows the properties of the obtained resin composition.

As is clear from Table 2, the present invention has excellent fluidity and moldability.

[0030]

[Table 1]

However, bismaleimide A = bis(4-maleimidophenyl)methane allylphenol A = 2,2-bis(3-allyl-4-
Hydroxyphenyl)propane Spherical silica A = Spherical silica with an average particle size of 18 μm Spherical silica B = Spherical silica with an average particle size of 0.9 μm Spherical silica C =
Spherical silica with an average particle size of 0.3 μm Spherical silica D = Aerosil 200 Coupling agent A = γ-glycidoxypropoxytrimethoxysilane peroxide A = Butyl levulinate di-tert-butyl peroxyketal peroxide B = 1 ,4-bis(2-(2-(tert-butylperoxy)propyl))benzene

[0032]

[Table 2]

(1) Fluidity was measured using a flow tester (manufactured by Shimadzu)
The measurement was carried out under the conditions of 180° C., nozzle diameter of 1 mm, and load of 10 kg.

(2) Inject using a transfer molding machine at an injection pressure of 100 kg/mm2, and at a mold temperature of 180°C.
After holding the air vent for 30 μm, the length of the burr (resin leakage) that appeared on the air vent with a gap of 30 μm was measured from the air vent inlet.

[0035]

Effects of the Invention The composition of the present invention has excellent heat resistance and moldability by employing a specific resin component, and in particular,
By using a specific silica, it has excellent fluidity during molding and is less likely to generate burrs.

Claims (1)

[Claims] [Claim 1] A. A polymaleimide compound having two or more maleimide groups in the molecule; B. An allylphenol compound represented by the following general formula (1) (X is C(CH3)2, SO2, SO, S,
consisting of either O or CO), [Chemical formula 1]C. A resin composition for semiconductor encapsulation, comprising as an essential component spherical silica whose primary particles have an average particle size of 7 nm or more and 50 nm or less, accounting for 0.5% by weight or more and 7% by weight or less of the total silica.