JPH04325540A - Resin composition for semiconductor sealing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 thermosetting resin composition having excellent moisture resistance, fluidity, and heat resistance.

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 strict 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
In general, polyimide resins have low solubility in organic solvents, and have high melting points or softening temperatures, so that moldability is not necessarily good.

Polymaleimide resins are known as polyimide resins with improved moldability. For a resin composition of a polymaleimide resin and o,o'-diallyl bisphenol A, see Japanese Patent Publication No. 55-39242, and for a resin composition of a polymaleimide resin and a diallyl ether of bisphenol S, see JP-A-53-134099. , for resin compositions of polymaleimide resins and allyl etherified phenol novolac resins, see JP-A-62-1.
Examples such as No. 1716 are known. Furthermore, IC,L
It is known that silica, which has a low coefficient of thermal expansion, is added to plastic encapsulating materials in order to reduce thermal stress on the surface of SI, and a resin composition developed for semiconductor encapsulation by adding silica to polymaleimide resin. About JP-A-6
Examples such as No. 3-230728 are known. but,
In these documents, there is no description of the influence of the shape, average particle size, and filling amount of silica on fluidity and moisture resistance during molding. In particular, with regard to moisture resistance, increasing the amount of filled silica is generally effective in reducing the amount of moisture absorbed by the entire sealing material, but there have been few that have been able to satisfy the recent strict demands for suppressing the amount of moisture absorbed.

Regarding this point, it has been reported in Japanese Patent Publication No. 62-040368 and No. 63-0 that it is effective to improve moisture resistance by making the surface of silica hydrophobic with respect to epoxy resins.
It is known as No. 25009. However, as mentioned above, epoxy resins do not have sufficient heat resistance.

[0005]

[Problems to be Solved by the Invention] Even in highly heat-resistant polyimide resin-based semiconductor encapsulants, it is necessary to have a high filling rate of silica, which has a low coefficient of thermal expansion, in order to reduce thermal stress. Although silica is effective in reducing moisture absorption, especially in recent years, when silica is packed much higher than before due to the need to improve various properties, the silica surface area increases significantly and the overall compound This promoted an increase in water absorption and caused a decrease in moisture resistance. Furthermore, untreated silica aggregates through adsorbed water, resulting in decreased fluidity and instability. Furthermore, when the surface is treated with a so-called silane coupling agent having a reactive functional group, fluidity is significantly reduced when the silica is highly loaded due to aggregation of the silica after the treatment.

[0006]

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the present inventors have found that when highly filling silica into a polymerimide resin, the surface of the silica is treated in advance with a specific organosilicon compound. It was discovered that a resin composition having high heat resistance, high fluidity, and excellent moisture resistance could be obtained by this method, and the present invention was achieved.

That is, an object of the present invention is to provide a thermosetting resin containing the following components A and B as essential components. A. Polymaleimide resin having two or more maleimide groups in the molecule represented by the following general formula (3) (where n is an integer of 2 or more, and Y represents a polyvalent residue of 2 or more valences).

[0008]

[Chemical formula 3] B. Silica surface-treated using a surface treatment agent containing at least an organosilicon compound represented by the following general formula (1)

[0009]

embedded image (R1 to R4 represent a hydroxyl group, an alkoxy group, an aryl group, or an alkyl group having 1 to 10 carbon atoms, at least one of which is a hydroxyl group or an alkoxy group, and at least one of which is an aryl group) group or carbon number 1-10
number of alkyl groups. ) Hereinafter, the present invention will be explained in further detail.

The polymaleimide resin (A) having two or more maleimide groups in the molecule used in the present invention is a polymaleimide resin having two or more maleimide groups in the molecule represented by the above general formula (3). If so, there are no particular limitations. Here, n represents an integer of 2 or more, and Y represents a multivalent residue of 2 or more valences. Y may be any aliphatic, aromatic, alicyclic, or heterocyclic residue as long as it is a divalent or higher polyvalent residue, but an aromatic residue is preferable.

Polymaleimide resin (A) used in the present invention
is easily obtained by reacting a diamine or polyamine with maleic anhydride. The diamine has the general formula (H2
It is a compound represented by N)nY (n is 2, Y is the same as Y in general formula (3) and represents a divalent residue). Specifically, the polymaleimide resin obtained by the reaction of diamine and maleic anhydride includes aliphatic polymaleimide, bis(maleimidophenyl) such as 1,2-dimaleimidoethane, 1,3-dimaleimidopropane, etc. Methane, bis(3-ethyl-4-maleimidophenyl)methane, bis(3-ethyl-4-maleimido-5-methylphenyl)methane, 2,7-dimalimidofluorene,
1,3-dimaleimidobenzene, 1,4-dimaleimidobenzene, 2,4-dimalimidotoluene, bis(maleimidophenyl)sulfone, bis(maleimidophenyl)ether, 2,2-bis(4-(4- Aromatic aromas such as maleimidophenoxy)phenyl)propane, bis(4-(4-maleimidophenoxy)phenyl)sulfone, 1,3-bis(2-(3-maleimidophenyl)propyl)benzene (including isomers of each), etc. Examples include group polymaleimides, alicyclic polymaleimides such as 1,4-dimaleimide cyclohexane, and heterocyclic polymaleimides such as bis(maleimidophenyl)thiophene. The polymaleimide resin 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)n Y (n is an integer of 3 or more, Y
is the same as Y in general formula (3) and represents a trivalent residue). Further, specific examples of the polymaleimide resin obtained by the reaction of a polyamine and maleic anhydride include a maleimide of a polycondensate of aniline or a derivative thereof and formalin. Furthermore, it is also possible to use a combination of two or more of these to form maleimide, or to use a combination of two or more of these after maleimidating each of the above diamines or polyamines. . Furthermore, monomaleimide can be added within a range that does not impair heat resistance, moisture resistance, and water resistance.

The silica (B) surface-treated with the organosilicon compound (1) used in the present invention will be described in detail. At least one of R1 to R4 of the organosilicon compound (1) is a hydroxyl group or an alkoxy group, and at least one is an aryl group or an alkyl group having 1 to 10 carbon atoms. The alkoxy group is not particularly limited, but
A methoxy group or an ethoxy group is preferred in terms of reactivity with silanol on the silica surface and reactivity in self-condensation. The aryl group is not particularly limited, but phenyl and naphthyl groups are easily used, and some of the hydrogens on their aromatic rings may be substituted with other functional groups. As the alkyl group having 1 to 10 carbon atoms, a methyl group, an ethyl group, a t-butyl group, etc. are preferable, and a methyl group is particularly preferable from the viewpoint of heat resistance. Specific examples of compound (1) include phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, and trimethyldimethoxy. Silane, butyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, phenyldimethylmethoxysilane, triphenylsilanol, etc. In particular, compounds with phenyl groups not only hydrophobize the surface of silica and increase moisture resistance, but also have good affinity with the imide resin used in the present invention and high heat resistance, so they can maintain mechanical properties and improve moisture resistance. preferred for improvement.

[0013] In surface treatment of silica, it is essential to use compound (1) in order to maintain moisture resistance and fluidity.
It is not necessarily limited to the use of a single compound, and a plurality of the above-mentioned exemplified compounds may be used in combination. Compounds commonly used for surface treatment, such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(β-methoxyethoxy)silane, may also be used. , γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β- (aminoethyl)-γ-
Aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane , γ-chloropropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, etc. may be used to further improve the bonding with the resin. At this time, it is preferable that the amount of compound (1) is 30% or more of the total silica surface area from the viewpoint of moisture resistance and fluidity. The total amount of the surface treatment agent containing compound (1) depends on the specific surface area of the silica used, but is generally 0.1 to 5% by weight based on the silica, and is preferably a proportion of the specific surface area of the silica used and the surface treatment agent. The surface treatment agent is prepared in accordance with the desired physical properties based on the value calculated from the minimum coverage area, but it is preferable to prepare the surface treatment agent in an amount that covers exactly one layer of the silica surface, as this facilitates excellent effects.

[0014] As a method for surface treatment of silica,
The stock solution may be treated directly while stirring with a Henschel mixer or the like, or it may be diluted with water and/or a solvent such as alcohol, acetone, etc. and then added. Also, at that time,
In order to speed up the processing speed, heating may be performed or a catalyst such as an acid or a base may be added. In addition, silica can be dispersed in a nonpolar solvent such as toluene, xylene, hexane, etc., and water, a catalyst, and a surface treatment agent can be added thereto for treatment. Among these methods, an appropriate surface treatment method may be selected depending on the surface treatment agent used, the properties of the silica, and the state and equipment. In addition, when the silica to be surface-treated consists of two or more silica groups, the surface treatment may be performed for each group, or the silica groups may be mixed in advance and then surface-treated. good.

[0015] The silica surface-treated by the above method is preferably finally dried and heat-treated at a temperature of 90°C or higher. Optimum values for heat treatment temperature and treatment time can be easily determined by analyzing the surface of silica using infrared absorption spectroscopy or by tracking changes in weight. At least 30% of the total surface area of the required silica will not be moisture resistant or resistant unless the surface is previously treated with compound (1) using the method described above.
Although the effect of improving fluidity is small, it is not necessary to use all of the surface treatment agent to be used before mixing silica and resin. For example, the surface of the silica may be treated with a portion of the surface treatment agent in advance, and the remaining surface treatment agent may be added at the time of mixing the silica and the resin. In this case, it is desirable that 30% or more of the total surface area of the silica be treated with the organosilicon compound (1) before mixing the silica and the resin.

[0016] In the present invention, when the main purpose is to create a compound with high silica loading, and the loading is approximately 60% by weight or more, good fluidity cannot be ensured with only a single silica having a narrow particle size distribution. becomes difficult. In order to improve fluidity, it is best to use silica with as wide a particle size distribution as possible, or to combine two or more groups of silicas with different average particle sizes. Each type of silica used may be spherical silica or crushed silica, and a mixture of both may be used.
The silica group having the largest average particle size is preferably spherical silica for good fluidity. In addition, the particle size ratio of two silica groups that are close to each other is not necessarily regulated, but the minimum particle size within the range specified by the standard deviation value of the silica group with a large average particle size and the small average particle size. The ratio of the minimum particle size in the range defined by the standard deviation value of the silica group is 2 or more, and the average particle size of the silica group is larger than the total volume of the two silica groups whose average particle sizes are close to each other. Silica in a proportion of 20 to 95% by volume is preferred for ensuring fluidity.

Silica is added as much as possible to lower the coefficient of thermal expansion of the cured product after the composition is cured, so it is undesirable that the addition of silica lowers the electrical properties, so impurities such as uranium and thorium are added. It is desirable that there are few elements. The average particle size of silica is 0.05-15
0 μm is preferred. If the average particle size of silica is 150 μm or more, it will not be easily dispersed with silica having a smaller average particle size and will be easily separated, making uniform mixing and uniform molding difficult. When the diameter is less than 0.05 μm, the specific surface area of silica increases and agglomeration tends to occur easily, and the viscosity of the resin composition increases, resulting in a tendency for the fluidity to decrease.

[0018] By kneading silica that satisfies the above conditions of average particle size, particle size distribution, shape, average particle size ratio of silica, and volume ratio of silica with the above-mentioned polymaleimide resin, the average particle size can be reduced. It becomes possible to efficiently fill the gaps between silica having a large average particle size with the silica having a small diameter, and to increase the amount of silica filled in the entire resin composition while maintaining a high degree of fluidity.

The essential components of the semiconductor encapsulating resin composition of the present invention are the above-mentioned polymaleimide resin (A) and silica (B).
However, it is preferable to further contain an allylphenol derivative (C) represented by the following general formula (3).

[0020]

[Chemical formula 5] (In formula (3), X is C(CH3)2, SO2, SO
, S, O, and CO. ) Allylphenol derivative (C) specifically includes 2,
2-bis(3-allyl-4-hydroxyphenyl)propane, bis(3-allyl-4-hydroxyphenyl)sulfone, bis(3-allyl-4-hydroxyphenyl)
Examples include sulfoxide, bis(3-allyl-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.

The blending ratio of the polymaleimide resin (A) and the allylphenol derivative (C) is such that the allyl group is in the range of 0.5 to 1.5 equivalents per equivalent of the maleimide functional group of the polymaleimide resin (A). It is preferable that the phenol derivative (3) is included as shown in . Allyl group is 0.5
If the amount is less than the equivalent, the molded product will become brittle, and if it is more than 1.5 equivalents, the heat resistance will decrease.

The method of curing the composition of the present invention is easily accomplished by heating from the outside, but by adding a catalyst or curing accelerator, the molding temperature or molding time may 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, and basic compounds such as organic amine compounds. Specific examples thereof include ethyl levulinate-tert-butyl peroxyketal, butyl levulinate-tert-butyl peroxyketal, cyclohexanone-tert-butyl peroxyketal, azoisobutyronitrile, tert-butyl perbenzoate, and dichlorobutyl peroxyketal. Milperoxide, benzoyl peroxide, 1,4-bis(2-(2-(te)
rt-butylperoxy)propyl)) benzene or tributylamine, 4-(N,N-dimethylamino)
Examples include pyridine, lutidine, and 2-ethyl-4-methylimidazole.

[0023] 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, an internal mold release agent such as an organic fatty acid, a metal salt of an organic fatty acid, a natural wax, or a synthetic wax can be added as necessary. In this case, if only low polarity materials such as aliphatic esters or polyethylenes are used, the effect of addition will be small, and higher fatty acids with stronger polar groups, such as stearic acid and montanic acid, and/or their metal salts, etc. It is preferable to use or use them together.

[0024]Furthermore, functionality improvers such as halogen compounds, flame retardants such as antimony oxide, colorants such as carbon black, and plasticizers such as nitrile rubber and silicone resins can be added.

[0025]

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. Reference Example 1 Production of mixed resin Bis(4-maleimidophenyl)methane 57 parts by weight, 2
, 51 parts by weight of 2-bis(3-allyl-4-hydroxyphenyl)propane, and 25 parts by weight of bismaleimide oligomer (trade name K-601; manufactured by Technochemy) were heated at 130°C in a flask until uniform. A resin composition (mixed resin) was obtained.

Reference Example 2 Production average particle size of mixed silica 1
Mixed silica (Silica A
) was obtained. Reference Example 3 Production of surface-treated silica 1 While thoroughly mixing silica A at room temperature, add 1% by weight of phenyltriethoxysilane (silica B), or 1% by weight of methyltrimethoxysilane (silica C), or , 1% by weight of phenyltrimethoxysilane (Silica D
), or 1% by weight of diphenyldimethoxysilane (
Silica E) was added and stirring continued for an additional hour. Thereafter, the mixture was allowed to stand for a day and night, and then dried at 130° C. for 1 hour to obtain various surface-treated silicas shown in Examples.

Reference Example 4 Production of surface-treated silica 2 While thoroughly mixing silica A at room temperature, 1% by weight of γ-glycidoxypropyltrimethoxysilane (silica F) was added thereto.
Alternatively, 1% by weight of γ-methacryloxypropyltrimethoxysilane (Silica G) or 1% by weight of γ-aminopropyltriethoxysilane (Silica H) was added, and stirring was continued for an additional hour. Thereafter, the mixture was allowed to stand for a day and night, and then dried at 130° C. for 1 hour to obtain various surface-treated silicas shown in Comparative Examples.

Examples 1 to 2, Comparative Examples 1 to 5 Two rolls were used to prepare a mixed resin, silica, and depending on the conditions, a silane coupling agent, a mold release agent, and a curing accelerator as shown in Table 1 (wt%). A resin composition was obtained by mixing at 80 to 100°C. After cooling, it was crushed, tableted, and molded into a test piece using a transfer molding machine. In addition, a high temperature and high humidity test (PCT) and fluidity evaluation were conducted.

[0029] The mold release agent 1 is carnauba wax, the mold release agent 2 is sodium stearate, and the hardening agent 1 is butyl-tert-butyl peroxyketal levulinate (trade name: Perhexa V; manufactured by NOF Corporation), hardened. Agent 2 is 1,4-
It is bis(2-(2-(tert-butylperoxy)propyl)))benzene (trade name: Perbutyl P; manufactured by NOF Corporation).

[0030]Moreover, the moisture absorption rate and volume resistivity are PCT (1
30° C., 100%, 100 hr), and fluidity was determined by whether or not a suitable test piece was obtained, and those with sufficient fluidity were expressed as ◎, and those with poor fluidity were expressed as ×.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Effects of the Invention] The resin composition of the present invention is highly silica-filled, has excellent moisture resistance, fluidity, and high heat resistance, and is therefore very suitable for semiconductor encapsulation.

Claims (2)

[Claims] [Claim 1] A. Polymaleimide resin (A) having two or more maleimide groups in the molecule; and B. Silica (B) surface-treated using a surface treatment agent containing at least an organosilicon compound represented by the following general formula (1) [Formula 1] (R1 to R4 are a hydroxyl group, an alkoxy group, an aryl group, or a carbon number 1 ~10 alkyl groups, at least one of which is a hydroxyl group or an alkoxy group, and at least one is an aryl group or has 1 to 10 carbon atoms
number of alkyl groups. ) as an essential component [Claim 2] Polymaleimide resin (A) according to Claim 1
, in addition to silica (B), an allylphenol derivative (C) represented by the following general formula (2) (X is C(CH3)
2, a divalent group selected from SO2, SO, S, O, and CO) [Chemical formula 2]