JPH10195280A - Flame-retardant epoxy resin composition for semiconductor sealing and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-retardant epoxy resin composition free of a bromine compound for semiconductor sealing, and to provide a semiconductor device sealed by the cured composition. SOLUTION: This flame-retardant epoxy resin composition for semiconductor sealing is composed of, as the essential components, (A) an epoxy resin, (B) a phenol resin, its phenolic hydroxyl group accounting for 0.5 to 1.6 mols per mol of the epoxy group in the component A, (C) an inorganic filler, accounting for 550 to 1,000 pts.wt. per 100 pts.wt. of the total quantity of the components A and B, (D) powdered antimony pentoxide produced by the sol-gel process, accounting for 0.5 to 20 pts.wt. per 100 pts.wt. of the total quantity of the components A and B, and (E) a cured or uncured organopolysiloxane accounting for 0.1 to 10 pts.wt. per 100 pts.wt. of the total quantity of the components A and B, and contains no bromine compound. The epoxy resin composition gives the cured composition which simultaneously shows flame retardancy and heat-resistance even without incorporating any bromine compound, making the other objective semiconductor device sealed by the cured composition reliable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant epoxy resin composition for semiconductor encapsulation containing no bromine compound and a semiconductor device sealed with a cured product thereof.

[0002]

2. Description of the Related Art In recent years,
As the speed of the device increases, the amount of heat generated by the element becomes extremely large, and the temperature of the package itself becomes high. This is a serious problem in terms of reliability. On the other hand, in order to improve solder reflow resistance, the glass transition temperature is 100 ° C.
The front and rear sealing resins are being used. Against this background, how to maintain reliability at high temperatures is an important issue in the semiconductor industry.

[0003] The most problematic defect at high temperature is
Bromine compounds and antimony compounds used as flame retardants at high temperatures are decomposed and cause a chemical reaction at the connection between the gold wire and aluminum, which increases the resistance of the connection and sometimes leads to disconnection . This defect becomes remarkable especially when a material having a low glass transition temperature is used as the sealing material.

That is, flame retardancy and heat resistance are improved by using antimony pentoxide and a bromine compound in combination, and antimony pentoxide and bromine with a Na content of 0.03 to 0.06% are used. It is already well known to improve the heat resistance by using compounds, and in some cases bismuth trioxide and hydrated magnesium aluminum carbonate (U.S. Pat. No. 4,282,136, Japanese Patent Publication No. 6-8379).
No. 6-508857).

However, since all of these use a bromine compound, carbon-bromine bonds are decomposed at a high temperature and bromine is easily liberated, so that compounds such as an ion trapping agent and a pH adjusting agent are used. Was indispensable.

Accordingly, the present invention provides a flame-retardant epoxy resin composition for semiconductor encapsulation which achieves both flame retardancy and heat resistance without adding a bromine compound, and a semiconductor device encapsulated with a cured product thereof. The purpose is to provide.

[0007]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that an epoxy resin composition containing a large amount of filler is
By using antimony pentoxide and organopolysiloxane or its cured product of very high purity produced by the sol-gel method in combination, flame retardancy can be achieved without using a bromine compound, and the reliability at high temperatures is also excellent. It has been found that a resin composition for encapsulating a semiconductor element can be obtained.

That is, the present invention provides: (A) an epoxy resin; (B) a phenolic resin: an amount in which the phenolic hydroxyl group is 0.5 to 1.6 mol per 1 mol of the epoxy group of the component (A); C) Inorganic filler: Total amount of components (A) and (B) 1
(D) antimony pentoxide powder obtained by the sol-gel method: 0.5 to 20 parts by weight based on 100 parts by weight of the total of components (A) and (B). Parts by weight, (E) an organopolysiloxane or a cured product thereof:
0.1 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B).
Provided is a flame-retardant epoxy resin composition for encapsulating a semiconductor, comprising 1 to 10 parts by weight as an essential component and containing no bromine compound, and a semiconductor device encapsulated with a cured product of the composition. .

Hereinafter, the present invention will be described in detail. As the epoxy resin of the component (A) used in the present invention, any conventionally known epoxy resin having two or more epoxy groups per molecule can be used. do not use. As the epoxy resin, in particular, bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin, naphthalene epoxy resin, biphenyl epoxy resin,
A cyclopentadiene type epoxy resin is exemplified.
Among these epoxy resins, those having a naphthalene type epoxy resin, a biphenyl type epoxy resin or a liquid crystal structure represented by the following structural formula are desirable.

[0010]

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The total chlorine content in these epoxy resins is 1,500 ppm or less, preferably 1,000 ppm or less. Further, it is preferable that the extraction water chlorine in 20 hours at 120 ° C. and 50% epoxy resin concentration is 5 ppm or less. If the total chlorine content exceeds 1,500 ppm and the amount of chlorine in the extracted water exceeds 5 ppm, the moisture resistance reliability of the semiconductor may be reduced.

In the present invention, a phenol resin is used as a curing agent of the component (B). Any phenolic resin can be used as long as it has two or more phenolic hydroxyl groups in one molecule. Particularly, a phenol novolak resin, a cresol novolak resin, a phenol aralkyl resin, a naphthalene-type phenol resin, and a cyclopentadiene-type phenol resin are exemplified. Among them, those containing a phenolic hydroxyl group having the following structure are desirable.

[0013]

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The chlorine ions and sodium ions extracted from the phenol resin are all 10 ppm or less, preferably 5 ppm or less.

The mixing ratio of the epoxy resin to the phenol resin is such that the phenolic hydroxyl group is 0.1 mole per 1 mole of the epoxy group.
The amount is 5 to 1.6 mol, preferably 0.6 to 1.4 mol. If the amount is less than 0.5 mol, the hydroxyl group becomes insufficient, the homopolymerization ratio of the epoxy group increases, and the glass transition temperature decreases. On the other hand, if it exceeds 1.6 mol, the ratio of the phenolic hydroxyl group becomes high, the reactivity is lowered, and the crosslink density is low and sufficient strength cannot be obtained.

The epoxy resin composition of the present invention comprises
A curing accelerator can be blended. As the curing accelerator, phosphorus-based, imidazole derivatives, cycloamidine-based derivatives and the like can be used. The amount of the curing accelerator is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the total of the epoxy resin and the phenol resin.

The filler of the component (C) used in the present invention includes fused silica pulverized by a ball mill or the like, spherical silica obtained by flame melting, spherical silica produced by a sol-gel method, crystalline silica, and the like. Alumina, boron nitride, aluminum nitride, silicon nitride, magnesia, magnesium silicate and the like are used. When the semiconductor element generates a large amount of heat, it is preferable to use alumina, boron nitride, aluminum nitride, silicon nitride, or the like having a large thermal conductivity and a small expansion coefficient as a filler. Further, it may be used by blending with fused silica or the like. Further, in order to seal a more precise device, the melt viscosity at 175 ° C. is 200 poise or less,
Desirably, an epoxy resin composition of 100 poise or less is desired. Therefore, it is desirable that the inorganic filler has a particle size distribution that enables spherical close packing. The particle size distribution of the filler that can be used here has an average particle size of 4
In 30 .mu.m, a maximum particle size of 74μm or less, and more preferably the maximum particle size has a particle size distribution 50 [mu] m, a specific surface area of 2.5 m ² / g or less, preferably 1.0~3.0m ² /
g is preferred.

The amount of the inorganic filler used is 550 to 550 parts per 100 parts by weight of the total amount of the epoxy resin and the phenol resin.
It is 1,000 parts by weight, preferably 750 to 950 parts by weight. If the amount is less than 550 parts by weight, the flame retardation is insufficient even by the addition of antimony pentoxide, the expansion coefficient cannot be sufficiently reduced, the water absorption increases, and the package cracks at the temperature at the time of solder reflow. Will enter. On the other hand, if it exceeds 1,000 parts by weight, the viscosity becomes too high,
It cannot be molded. In this case, the content of the inorganic filler in the epoxy resin composition is preferably 82 to 91% by weight, particularly preferably 86 to 90.5% by weight.

The epoxy resin composition may contain, if necessary, silica which has not been treated with ultrafine particles such as Aerosil, or whose surface has been hydrophobized with an organosilyl group or the like to impart thixotropy. It can also be added as a part. When this kind of ultrafine silica is used, it is preferable to use a mixing device such as a ball mill in advance and uniformly mix it with other fillers before use.

Antimony pentoxide used as a flame retardant in the present invention is produced by a sol-gel method. This is different from that obtained by oxidation of antimony metal and is highly purified in purity. Therefore, heavy metals such as lead and arsenic remaining in antimony pentoxide, alkali metal ions and halogen ions are all 100 ppm or less, usually 0.01 to 100 ppm.
ppm, preferably 0.1 to 50 ppm.

The particle size of antimony pentoxide used in the present invention is preferably as small as possible. Usually usable particle sizes are those having an average primary particle size of 0.01 to 5 μm and a specific surface area of 1 to 100 m ² / g. More preferably, the average primary particle size is 0.01 to 1 μm and the specific surface area is 20.
１００100 m ² / g.

The amount of antimony pentoxide used is 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the total amount of the epoxy resin and the curing agent. If the amount is less than 0.5 part by weight, the flame retardancy is insufficient. If the amount exceeds 20 parts by weight, the cost is increased, and the antimony content is too large, which impairs the reliability of the semiconductor when stored at a high temperature for a long time. There is a risk.

Next, the epoxy resin composition of the present invention comprises:
An organopolysiloxane or a cured product thereof is blended as the component (E). That is, in the present invention, by combining the high-purity antimony pentoxide and the organopolysiloxane or a cured product thereof, both flame retardancy and heat resistance can be achieved without using a bromine compound conventionally known as an essential component. It was made. Therefore, a highly reliable resin composition can be obtained without the above-mentioned inconvenience, and the flame-retardant grade UL can be obtained without containing a flame retardant such as antimony trioxide Sb ₂ O ₃ or a bromine compound. -9
It is excellent in that 4V-0 can be achieved.

The flame retardant effect of the organopolysiloxane compound or the cured product thereof includes the following. That is, the organopolysiloxane compound generates carbon dioxide, carbon monoxide, water and the like by burning, and leaves silica (SiO ₂ ) as ash. Also,
Generally, the combustion state of an organopolysiloxane compound is smaller than that of other oils (such as mineral oil) in that the amount of generated gas is small and the combustion heat is small, so that the flame is small and the spread of fire to the surroundings is suppressed. .

As the component (E), the following average composition formula is used.
(1) R _aSiO_{(4-a) / 2} ... the organopolysiloxane and organopolysiloxane represented by (1)
Use by appropriately selecting from fine powders of cured oxane
Can be.

Here, in the formula (1), R is an unsubstituted or substituted monovalent hydrocarbon group, and the unsubstituted monovalent hydrocarbon group preferably has 1 to 10 carbon atoms, particularly preferably 1 to 6 carbon atoms. . Specifically, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclohexyl,
Alkyl group such as octyl group, vinyl group, allyl group, propenyl group, alkenyl group such as butenyl group, phenyl group,
An aryl group such as a tolyl group and a naphthyl group; an aralkyl group such as a benzyl group and a phenylethyl group; Examples of the substituted monovalent hydrocarbon group include those in which part or all of the hydrogen atoms of the unsubstituted monovalent hydrocarbon group are substituted with a halogen atom (eg, fluorine), a cyano group, or the like. And functional groups such as epoxy groups, carboxyl groups, carbinol groups, (methyl) styryl groups, (meth) acrylic groups, mercapto groups, polyether groups, higher fatty acid ester groups, and higher alkyl groups having 12 or more carbon atoms. Monovalent groups are mentioned. In addition, these functional groups usually have 2 to 10 carbon atoms, particularly about 3 to 8 carbon atoms, and may be an alkylene group, an arylene group, or a combination thereof, which may intervene an oxygen atom or an imino group (—NH—). To the silicon atom through the alkylene arylene group.

In the formula (1), a is 1 ≦ a ≦
3, especially a positive number in the range of 1.5 ≦ a ≦ 2.5.

Here, as the organopolysiloxane compound represented by the above formula (1), the following compounds can be listed according to their structures.

Examples of the straight organopolysiloxane compound include dimethylpolysiloxane and methylphenylpolysiloxane.

Examples of the modified organopolysiloxane compound include amino-modified polyorganosiloxane, epoxy-modified organopolysiloxane, carboxyl-modified organopolysiloxane, carbinol-modified organopolysiloxane, methacryl-modified organopolysiloxane, mercapto-modified organopolysiloxane, and phenol-modified organopolysiloxane. Organopolysiloxane, one-terminal reactive organopolysiloxane, heterofunctional group-modified organopolysiloxane, polyether-modified organopolysiloxane, methylstyryl-modified organopolysiloxane, higher alkyl-modified organopolysiloxane, higher fatty acid ester-modified organopolysiloxane, higher-grade Fluorine-modified organopolysiloxanes such as fatty acid-containing organopolysiloxanes and trifluoropropylmethylpolysiloxanes Hexane, and the like.

Examples of the organopolysiloxane resin include:
Methylpolysiloxane resins and methylphenylpolysiloxane resins, which have a carbon-carbon double bond in their structure, are known to have high flame retardancy.

The methylpolysiloxane resin is generally
iO_Two, CH_ThreeSiO_3/2, (CH_Three)_TwoSiO , (CH_Three)
_ThreeSiO_1/2Three-dimensional mesh formed by combining structural units
It is a copolymer having a structure.

The methylphenylpolysiloxane resin is
Generally SiO_Two, CH_ThreeSiO_3/2, C₆H_FiveSiO_3/2,
(CH_Three)_TwoSiO , (C₆H_Five)_ThreeSiO_1/2, (CH_Three)_Three
SiO_1/2, (C₆H_Five) (CH_Three) SiO , (C₆H_Five)_Two
SiO Three-dimensional network structure formed by combining various structural units
Is a copolymer of
High heat resistance.

The degree of polymerization (or the number of silicon atoms in the molecule) of the organopolysiloxane compound represented by the above formula (1)
Is preferably in the range of 5 to 1,000, especially 10 to 200. If the degree of polymerization is less than 5, low molecular weight may cause problems in volatility and compatibility. If it exceeds 000, the viscosity may be high and the dispersibility may be poor.

Among the organopolysiloxane compounds used as the component (E) in the present invention, a polyether-modified polyether group having a polyether group having a strong affinity with the matrix resin, in view of the compatibility between the matrix resin and the organopolysiloxane compound. Organopolysiloxane compounds are preferably used. Examples of the polyether-modified organopolysiloxane compound include the following polyether-modified organopolysiloxane compounds.

[0036]

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Specific examples of the polyether-modified organopolysiloxane include the following.

[0038]

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The above-mentioned polyether-modified organopolysiloxane compound is used as a compatibilizer, and an amino-functional group or an epoxy-functional group bonded to a silicon atom at the terminal of a molecular chain or in the middle of a molecular chain as exemplified below is used. Other organopolysiloxane compounds such as amino-modified organopolysiloxane and epoxy-modified organopolysiloxane may be used in combination.

[0040]

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This amino-modified organopolysiloxane,
Specific examples of the epoxy-modified organopolysiloxane include the following.

[0042]

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In the present invention, the organopolysiloxane cured product used as the component (E) is not particularly limited, and can be appropriately selected from those shown below. An organopolysiloxane rubber cured by an addition reaction of a composition containing a vinyl group-containing organopolysiloxane and an organohydrogenpolysiloxane in the presence of a platinum catalyst, a terminal silanol group and / or an alkoxy group-blocked organopolysiloxane; 3
An organopolysiloxane rubber obtained by curing a composition containing a silane having at least two or more hydrolyzable functional groups and / or a partially hydrolyzed condensate thereof and a condensation catalyst by a condensation reaction (where the condensation reaction includes dehydration, Dehydrogenation, dealcoholization, deoxime, deamine, deamide, decarboxylic acid,
Deketonization and the like can be mentioned. ), An organopolysiloxane rubber cured by heating with an organic peroxide, an organopolysiloxane rubber cured by ultraviolet irradiation, or a SiO ₂ unit and / or RSiO cured by each of the above reactions.
An organopolysiloxane resin containing _3/2 units (R is the same as described above) is exemplified. These organopolysiloxane cured products are used in the form of a powder that has been pulverized in advance with a pulverizer. The cured organopolysiloxane has a silanol group, a hydroxy group,
Those having a functional group such as a carboxy group, a vinyl group, an amino group, a mercapto group, an epoxy group, a methoxy group, and an ethoxy group may be used. In recent years, the gate size of a mold for molding an electronic component such as an IC has been reduced in package size,
The particle size of the organopolysiloxane cured product used in the present invention is preferably 50 μm or less in average particle size from the viewpoint of moldability, and usually 0.01 to 50 μm.
m, particularly preferably about 0.1 to 20 μm.

The amount of the organopolysiloxane compound or the cured product thereof is 1 in total of the epoxy resin and the curing agent.
0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, particularly preferably 0.5 to 2 parts by weight with respect to 00 parts by weight. This is because the effect of the oxidizing property may not be obtained, and if it exceeds 10 parts by weight, the mechanical strength is reduced.

The epoxy resin composition of the present invention may contain, if necessary, a conventionally known n-type resin for the purpose of lowering the viscosity.
Diluents such as butyl glycidyl ether, phenyl glycidyl ether, styrene oxide, t-butylphenyl glycidyl ether, dicyclopentadiene diepoxide, phenol, cresol, t-butylphenol can be added.

Furthermore, coupling agents such as silane coupling agents, titanium coupling agents, aluminum coupling agents and the like, coloring agents such as carbon black, nonionic surfactants, fluorine surfactants, silicone oils and the like. A wetting improver, an antifoaming agent, and the like can be optionally added.

The addition of a halogen scavenger for trapping released halogens in an amount of not more than 10% by weight, especially about 1 to 5% by weight, based on the whole composition, is not limited as long as the object and effects of the present invention are not impaired. Optional.

In the method for producing the epoxy resin composition of the present invention, the above-mentioned raw materials are uniformly mixed using a high-speed mixer or the like, and then sufficiently kneaded with a two-roll or continuous kneader. The kneading temperature is preferably from 50 to 110C. After kneading, the sheet is thinned, cooled and pulverized to produce an epoxy resin composition.

The epoxy resin composition of the present invention is used for encapsulating a semiconductor. In this case, the semiconductor device may be an integrated circuit which generates a large amount of heat which requires heat resistance, or a semiconductor which requires a high degree of reliability. And the like. Particularly, it is suitably used for sealing a high-speed memory, a CPU, and the like.

The method of molding the epoxy resin composition is not particularly limited, but it can be usually performed by transfer molding. Molding conditions are usually 165 to 18
5 ° C. for 1 to 3 minutes.

[0051]

According to the epoxy resin composition of the present invention,
A cured product having both flame retardancy and heat resistance is provided without blending a bromine compound. Therefore, a semiconductor device sealed with this cured product is highly reliable.

[0052]

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. In the following examples, all parts are parts by weight.

Examples 1 to 5 and Comparative Examples 1 to 4 The components shown in Table 1 were uniformly melted and kneaded with a hot roll, cooled and pulverized to obtain an epoxy resin composition for encapsulating a semiconductor element. Was.

Next, with respect to these compositions, the following (A)
(D) Various tests were performed. Table 1 shows the results. (A) Spiral flow 175 ° C, 70k using a mold conforming to EMMI standard
gf / cm^Two And the molding time was 120 seconds. (B) Flame retardancy test Based on UL-94, a 1/16 inch thick plate was formed,
Flame retardancy was investigated. (C) Formability Heat resistance test with aluminum simulated element using each sample
14-pin DIP for 175 ° C, 70kgf
/ Cm^Two Molding when sealed under the condition of molding time 120 seconds
I saw the nature. External voids, internal voids, unfilled molding defects
Pass if no molding occurs, fail if molding failure occurs
Passed. (D) High-temperature reliability Simulated elements and parts with aluminum wiring formed on a silicon chip
The 42 alloy frame plated with metal is 30μ thick.
175 ° C, 70kgf / c
m^Two Molds 14-pin DIP with a molding time of 120 seconds
did. 4 hours at 180 ° C
After post-curing for a certain period of time,
(168 hr). After that, the cured resin is smoked
Dissolve with acid and reduce the shear strength of the bonding part on the chip side.
It was measured. If the strength is less than half of the initial strength,
did.

[0055]

[Table 1]

[0056]

Embedded image * 5: KBM403 manufactured by Shin-Etsu Chemical Co., Ltd .; γ-glycidoxypropyltrimethoxysilane * 6: Not measured because the test piece cannot be molded

Antimony pentoxide A: manufactured by a sol-gel method (average particle size 0.3 μm, specific surface area 35 m ² / g,
Antimony pentoxide B: produced by oxidation of antimony metal (average particle size 5 μm, specific surface area 2.8 m ² / g, purity halogen ion 180 ppm) Organopolysiloxane (1) KF96: manufactured by Shin-Etsu Chemical Co., Ltd. Dimethylpolysiloxane end-blocked with a trimethylsilyl group (2) X-22-161: dimethylpolysiloxane modified with amino groups at both ends, manufactured by Shin-Etsu Chemical Co., Ltd. (3) X-22-3939A: polyether-modified with amino group, manufactured by Shin-Etsu Chemical Dimethylpolysiloxane (4) KR213: manufactured by Shin-Etsu Chemical Co., methoxy group equivalent 1
60-methylpolysiloxane resin (5) X-52-874C: a powder of a cured dimethylpolysiloxane having an average particle size of 10 to 15 μm, manufactured by Shin-Etsu Chemical Co., Ltd.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Okuse 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside Silicone Electronic Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Kazutoshi Tomiyoshi Matsuida-machi, Usui-gun, Gunma Prefecture Hitomi 1-10, Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory

Claims (3)

[Claims] (A) an epoxy resin; (B) a phenolic resin: an amount such that a phenolic hydroxyl group is 0.5 to 1.6 mol per 1 mol of an epoxy group of the component (A), and (C) an inorganic filler. Agent: Total amount of components (A) and (B) 1
(D) antimony pentoxide powder obtained by the sol-gel method: 0.5 to 20 parts by weight based on 100 parts by weight of the total of components (A) and (B). Parts by weight, (E) an organopolysiloxane or a cured product thereof:
0.1 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B)
A flame-retardant epoxy resin composition for encapsulating a semiconductor, comprising 1 to 10 parts by weight as an essential component and containing no bromine compound. 2. An organopolysiloxane of component (E)
The following average composition formula (1) R _aSiO_{(4-a) / 2} ... (1) (where R Is an unsubstituted or substituted monovalent hydrocarbon group, and a is 1
Indicates a positive number of ≦ a ≦ 3. )
2. The epoxy resin composition according to 1. 3. A semiconductor device sealed with a cured product of the epoxy resin composition according to claim 1.