JP2002265759A - Semiconductor sealing epoxy resin composition and semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor sealing epoxy resin composition which has not only high flame retardance but also excellent moisture resistance and flowability. SOLUTION: The semiconductor sealing epoxy resin composition comprises (A) an epoxy resin, (B) a phenolic resin, (C) an inorganic filler, and (D) an organic phosphorus compound represented by formula (1) (wherein R1 , R2 , and R3 are each a monovalent organic group and may be the same or different from one another).

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 for semiconductor encapsulation having not only flame retardancy but also excellent moisture resistance reliability and fluidity, and a semiconductor device using the same.

[0002]

2. Description of the Related Art Conventionally, transistors, ICs, and LSs have been used.
Semiconductor devices such as I have been encapsulated using an epoxy resin composition to form electronic components. Since it is indispensable that the electronic component complies with UL-94V-0, which is a standard of flame retardancy, a method of imparting flame retardancy by adding a brominated epoxy resin and antimony oxide has hitherto been used. Has been taken. However, in recent years, from the viewpoint of environmental protection, there has been a demand for a method of imparting flame retardancy without using the halogen-based flame retardant or the antimony compound.

[0003] In response to the above requirements, the use of metal hydroxides, boron compounds, red phosphorus compounds and the like has been studied for the purpose of imparting flame retardancy. There is a problem that the moldability is poor due to a decrease in the moldability, and the moisture resistance is deteriorated due to a large amount of impurities.

[0004]

For example, in the above-mentioned compounds, since metal hydroxides and the like have a plate-like shape, there is a drawback that the fluidity of the epoxy resin composition for sealing decreases. Was. In addition, red phosphorus compounds and the like have the drawback that impurity ions such as phosphoric acid are more likely to precipitate under high temperature and high humidity because they are easily dissolved in water, resulting in a decrease in the moisture resistance reliability. Further, although it is considered that the organic phosphorus compound can also impart flame retardancy, it has a drawback that the moisture resistance reliability is reduced as in the case of the above-mentioned red phosphorus compound.

[0005] The present invention has been made in view of the above circumstances, and an epoxy resin composition for semiconductor encapsulation having not only high flame retardancy but also excellent moisture resistance and fluidity, and can be obtained by using the same. An object is to provide a semiconductor device having high reliability.

[0006]

In order to achieve the above-mentioned object, the present invention provides, as a first gist, an epoxy resin composition for semiconductor encapsulation containing the following components (A) to (D). (A) Epoxy resin. (B) a phenolic resin. (C) an inorganic filler. (D) An organic phosphorus compound represented by the following general formula (1).

[0007]

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[0008] A second aspect of the present invention is a semiconductor device in which a semiconductor element is sealed with the above-mentioned epoxy resin composition for semiconductor sealing.

The inventors of the present invention have made it necessary to provide flame retardancy,
In addition, a series of studies were conducted for the purpose of obtaining an epoxy resin composition that could be a sealing material having excellent moisture resistance reliability and fluidity. As a result, when the specific organic phosphorus compound represented by the general formula (1) is used, not only excellent flame retardancy is imparted, but also excellent in moisture resistance reliability, and the metal hydroxide described above is used. The present inventors have found that the intended purpose can be achieved without lowering the fluidity unlike the products and the like, and have reached the present invention.

When the inorganic filler as the component (C) is used so as to have a content in a specific range, the balance between flame retardancy and fluidity becomes particularly good, and a more excellent sealing material is obtained. Will be able to do it.

[0011]

Next, embodiments of the present invention will be described in detail.

The epoxy resin composition for semiconductor encapsulation of the present invention comprises an epoxy resin (component A), a phenol resin (component B), an inorganic filler (component C), and a specific organic phosphorus compound (component D). And is usually obtained by using
It is in the form of a powder or a tablet obtained by compressing it.

The epoxy resin (component A) is not particularly limited, and various epoxy resins such as dicyclopentadiene type, cresol novolak type, phenol novolak type, bisphenol type, and biphenyl type can be used. These epoxy resins may be used alone or in combination of two or more. Among these epoxy resins, it is particularly preferable that the melting point or the softening point exceeds room temperature. For example, as a cresol novolak type epoxy resin, an epoxy equivalent of 180 to 2 is used.
10, those having a softening point of 60 to 110 ° C are preferably used. As the biphenyl type epoxy resin, those having an epoxy equivalent of 180 to 210 and a melting point of 80 to 120 ° C are preferably used.

The phenol resin (component B) serves as a curing agent for the epoxy resin (component A), and is not particularly limited. The phenol resin is a dicyclopentadiene type phenol resin, a phenol novolak resin, and a cresol novolak resin. And phenol aralkyl resins. These phenol resins may be used alone or in combination of two or more. These phenolic resins have a hydroxyl equivalent of 70 to 250 and a softening point of 5
It is preferable to use one having a temperature of 0 to 110 ° C. And
Preferred combinations of the epoxy resin (A component) and the phenol resin (B component) include epoxy resin (A
When a cresol novolak type epoxy resin is used as the component), a phenol novolak resin is preferably used, and when a biphenyl type epoxy resin is used as the epoxy resin (component A), it is preferable to use a phenol aralkyl resin.

The mixing ratio of the epoxy resin (component A) and the phenol resin (component B) is preferably set to an amount sufficient to cure the epoxy resin. Generally, the total of hydroxyl groups of the phenol resin (component B) is 0.1 to 1 equivalent of epoxy group in the epoxy resin (component A).
It is preferable to mix so as to be 7 to 1.5 equivalents.
It is more preferably 0.9 to 1.2 equivalents.

The inorganic filler (component C) used together with the above-mentioned components A and B is not particularly limited, and includes various conventionally known fillers. Examples thereof include quartz glass powder, talc, silica powder (fused Silica powder, crystalline silica powder, etc.), alumina powder, aluminum nitride powder, silicon nitride powder and the like. These may be used alone or in combination of two or more. Among them, it is preferable to use the above silica powder from the viewpoint that the coefficient of linear expansion of the obtained cured product can be reduced, and among the above silica powders, it is particularly preferable to use a fused silica powder in terms of high filling and high fluidity. . Examples of the fused silica powder include a spherical fused silica powder and a crushed fused silica powder. From the viewpoint of fluidity, it is preferable to use a spherical fused silica powder. In particular, the average particle size is 10 to 60 μ
m, particularly preferably in the range of 25 to 45 μm. In addition, the said average particle diameter can be measured using a laser diffraction scattering type particle size distribution measuring device, for example.

The content of the inorganic filler (component C) is as follows:
It is preferably set within the range of 50 to 95% by weight of the entire epoxy resin composition, and particularly preferably 70 to 90% by weight. That is, if the content is too small, such as less than 50% by weight, the proportion of the organic component in the epoxy resin composition increases, and the flame retardant effect of the cured product becomes poor. This is because there is a tendency for the fluidity of the material to be significantly reduced.

The specific organic phosphorus compound (component D) used together with the components A to C is an organic phosphorus compound represented by the following general formula (1).

[0019]

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In the above formula (1), R ₁ , R ₂ and R ₃ are monovalent organic groups, and the number of carbons thereof is usually
1 to 15.

More specifically, as the organic phosphorus compound, a compound represented by the following general formula (2) is used.

[0022]

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Particularly, triphenylphosphine sulfide is preferable.

The content of the above organic phosphorus compound (D component) is
It is preferably set in the range of 0.5 to 20% by weight in the entire epoxy resin composition, and particularly preferably in the range of 2 to 10% by weight. That is, an organic phosphorus compound (D component)
If the content is too small, such as less than 0.5% by weight, the flame-retardant effect, which is an essential condition, is poor. Conversely, if it exceeds 20% by weight, the moisture resistance reliability tends to decrease. .

The epoxy resin composition for encapsulating a semiconductor of the present invention may further comprise, if necessary, a curing accelerator, a flame retardant other than the organic phosphorus compound as the component D, in addition to the components A to D,
Flame retardant aids, release agents, pigments and colorants such as carbon black, γ-glycidoxypropyltrimethoxysilane, γ
-Other additives such as a silane coupling agent such as mercaptopropyltrimethoxysilane and γ-aminoethylaminopropyltrimethoxysilane, and a low-stressing agent can be appropriately compounded.

Conventionally known curing accelerators are used as the above-mentioned curing accelerator. Specifically, organophosphorus compounds such as tetraphosphonium / tetraphenylborate and triphenylphosphine, and 1,8-diazabicyclo (5,4,
0) Undecene-7,1,5-diazabicyclo (4,
And diazabicycloalkene compounds such as (3,0) nonene-5. These may be used alone or in combination of two or more.

Examples of the release agent include compounds such as higher fatty acids, higher fatty acid esters, and higher fatty acid calcium. For example, carnauba wax and polyethylene wax are used, and these may be used alone or in combination of two or more. Can be

Examples of the low stress agent include butadiene rubbers such as methyl acrylate-butadiene-styrene copolymer and methyl methacrylate-butadiene-styrene copolymer, and silicone compounds. Further, an ion trapping agent such as hydrotalcites and bismuth hydroxide may be blended for the purpose of improving the reliability in the moisture resistance reliability test.

The epoxy resin composition for semiconductor encapsulation used in the present invention can be produced, for example, as follows. That is, the epoxy resin (A component), the phenol resin (B component), the inorganic filler (C component), the specific organic phosphorus compound (D component), and if necessary, other additives are appropriately added according to a conventional method. After mixing and melting and kneading in a heated state using a kneading machine such as a mixing roll, the mixture is cooled and solidified at room temperature. Thereafter, the desired epoxy resin composition can be produced by a series of steps of pulverizing by known means and tableting as necessary.

The sealing of the semiconductor element using the epoxy resin composition thus obtained is not particularly limited, and can be performed by a known molding method such as ordinary transfer molding.

In the semiconductor device thus obtained, the specific organic phosphorus compound (D component) is contained in the epoxy resin composition used as the encapsulating resin composition. The semiconductor device has high reliability and excellent moisture resistance reliability and fluidity, and thus has high reliability.

Next, examples will be described together with comparative examples.

First, the following components were prepared.

[Epoxy resin a] Cresol novolak type epoxy resin (epoxy equivalent 195, softening point 70 ° C.)

[Epoxy resin b] A biphenyl type epoxy resin represented by the following formula (b) (epoxy equivalent: 192;
(Melting point 107 ° C)

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[Phenol resin c] Phenol novolak resin (hydroxyl equivalent 107, softening point 85 ° C.)

[Phenol resin d] A phenol resin represented by the following formula (d) (having a hydroxyl equivalent of 174 and a softening point of 70)
℃)

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[Inorganic filler] Spherical fused silica powder (average particle size 30 μm)

[Curing accelerator] Triphenylphosphine

[Coupling agent] γ-mercaptopropyltrimethoxysilane

[Ester wax] Carnauba wax

[Olefin wax] Polyethylene wax

[Organic phosphorus compound e] An organic phosphorus compound represented by the following formula (e)

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[Red phosphorus flame retardant] A red phosphorus content of 93% by weight,
Average particle size 30μm

[Metal hydroxide] Mg-based composite metal hydroxide

[0046]

Examples 1 to 5 and Comparative Examples 1 to 3 The respective raw materials shown in the following Tables 1 and 2 were simultaneously mixed in the proportions shown in the same table and melt-kneaded for 3 minutes by a mixing roll machine (temperature: 100 ° C.). Next, the melted product was cooled and then pulverized to obtain a desired epoxy resin composition for semiconductor encapsulation.

[0047]

[Table 1]

[0048]

[Table 2]

Using the epoxy resin compositions of Examples and Comparative Examples obtained as described above, the impurity ion concentration was measured according to the following method. Further, a test piece having a thickness of 1.588 mm (1/16 inch) was molded using each of the epoxy resin compositions, and the flame retardancy was evaluated according to the method of UL-94V-0 standard. In addition, "pass" means UL-9
4V-0 is passed.

[Concentration of impurity ions] A cured product was prepared using each epoxy resin composition under the following conditions. Then, the obtained cured product is pulverized, passed through a net having a mesh size of 150 μm to collect 5 g, and then put into an extraction container together with 50 ml of ion-exchanged water to remove phosphate ions under extraction conditions of 160 ° C. × 20 hours. After extraction, the amount of ions was measured by ion chromatography analysis. (Curing body preparation conditions) Temperature: 175 ° C Time: 120 seconds

Using the epoxy resin compositions obtained in the above Examples and Comparative Examples, a semiconductor element (chip size: 7.5 × 7.5 mm) was subjected to transfer molding (condition: 175 ° C. × 120 seconds). A semiconductor package was obtained by post-curing at 175 ° C. × 5 hours. This package is an 80-pin QFP (quad flat package, size: 20 mm x 14 mm x thickness 2 mm), and has a die pad size of 8 x 8 mm.

Using the semiconductor package thus manufactured, a pressure cooker bias test (PCB
T test) (conditions: 130 ° C./85% RH, 3
0V bias). In the failure mode, leakage failure and open failure were measured, and the time until these failures occurred was measured to evaluate the humidity resistance reliability.

Further, fluidity was evaluated by a spiral flow (SF) shown in the following method.

[Measurement of Spiral Flow] Using a mold for measuring spiral flow, EMMI 1 was measured at 175 ± 5 ° C.
The spiral flow value was measured according to -66.

The results of the measurement and evaluation are shown in Tables 3 and 4 below.

[0056]

[Table 3]

[0057]

[Table 4]

As a result of the above Tables 3 and 4, all of the products of the examples show good flame retardancy and a small amount of phosphate ions.
Excellent results were also obtained in the moisture resistance reliability evaluation test and the fluidity evaluation test.

On the other hand, the product of Comparative Example 1 using the red phosphorus-based flame retardant had no problem with the flame retardancy, but had a large amount of phosphate ions and the result of the humidity resistance test was poor. Comparative Example 2 using a metal hydroxide as a flame retardant without using a phosphorus-based flame retardant
Although the product was good in the results of the flame retardancy test and the humidity resistance test, it had a short spiral flow value and was inferior in fluidity, and thus had a problem in use as a molding material. Furthermore, Comparative Example 3, which uses a biphenyl-type epoxy resin and a phenol aralkyl resin together with a metal hydroxide, has poor fluidity similarly to Comparative Example 2, and has a problem in use as a molding material.

[0060]

As described above, the present invention provides an epoxy resin composition for semiconductor encapsulation containing the specific organic phosphorus compound (component D) represented by the general formula (1) together with the components A to C. It is. For this reason, impurities under high-temperature and high-humidity conditions are harder to precipitate than conventional, as well as high flame retardancy, and excellent moisture resistance reliability and fluidity are obtained. Therefore, a semiconductor device having excellent reliability can be obtained by sealing a semiconductor element with the epoxy resin composition for semiconductor sealing.

When the inorganic filler as the component C is used so as to have a content in a specific range, the balance between the flame retardancy and the fluidity becomes particularly good, and a more excellent sealing material can be obtained. it can.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hironori Kobayashi 1-2-1 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 4J002 CC03X CC04X CC05X CC14X CD02W CD04W CD05W CD06W DE146 DF016 DJ026 DJ046 DL006 EW017 EW167 FD016 FD020 FD090 FD140 FD150 GQ01 4J036 AA02 AB01 AB07 AC08 AD01 AD08 AJ08 DA04 DA05 DD01 DD07 FA01 FA12 FB07 FB08 JA07 KA06 4M109 AA01 BA01 CA21 EA02 EB03 EB07 EB12 EC01 EC20

Claims (4)

[Claims] 1. An epoxy resin composition for semiconductor encapsulation comprising the following components (A) to (D): (A) Epoxy resin. (B) a phenolic resin. (C) an inorganic filler. (D) An organic phosphorus compound represented by the following general formula (1). Embedded image 2. The component (D) is represented by the following general formula (2)
The epoxy resin composition for semiconductor encapsulation according to claim 1, which is an organic phosphorus compound represented by the formula: Embedded image 3. The epoxy for semiconductor encapsulation according to claim 1, wherein the content of the inorganic filler as the component (C) is set in a range of 50 to 95% by weight of the whole epoxy resin composition. Resin composition. 4. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.