JP3512732B2 - Sealing resin composition and electronic component sealing device - Google Patents

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 an electronic component such as a semiconductor and an electronic component encapsulating device encapsulated with the resin composition. More specifically, the present invention relates to a highly reliable encapsulating resin composition that suppresses discoloration due to heat, particularly yellowing, and an electronic component encapsulating apparatus.

[0002]

2. Description of the Related Art Epoxy encapsulation materials used in electronic component encapsulation devices, especially non-colored and white materials, generally use an acid anhydride or a phenol novolac type resin as a curing agent. However, the encapsulating resin using an acid anhydride has a drawback that the reliability of the electronic component encapsulating apparatus, particularly the moisture resistance reliability, is remarkably lowered due to the deterioration of its hygroscopic property. Further, when the phenol novolac type phenol resin is used, the moisture resistance reliability is improved, but there is a drawback that the surface of the cured encapsulating resin is discolored by heating or long-term storage.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks, and has good moisture resistance reliability,
And despite using phenolic resin,
An object of the present invention is to provide a resin composition for encapsulation and an electronic component encapsulation device in which the surface of the encapsulating resin cured product does not discolor, particularly yellow even when heated and stored for a long time.

[0004]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above-mentioned object, the present inventors have found that the para-position of a phenol resin should have as few hydrogen atoms as possible in the α-position and the para-position. By using an alkyl-modified phenolic resin, hydrogen atoms are considerably reduced by the methylene bond at the α-position, while maintaining good moisture resistance,
The present invention has been completed by finding that discoloration due to heat and long-term storage is suppressed.

That is, the present invention is obtained by the reaction of (A) epoxy resin, (B) phenol substituted in the para-position with an alkyl group or para-hydroxyalkyl group, and formaldehyde, and a methylene bond is formed only in the α-position. The para-alkyl modified phenolic resin and the inorganic filler composed of (C) silica powder and titanium dioxide are used as essential components, and (C) is added to the resin composition.
A white resin composition for encapsulation, comprising an inorganic filler in a proportion of 60 to 95% by weight. Moreover, the electronic component sealing device is characterized in that an electronic component is sealed with the white resin composition for sealing.

The present invention will be described in detail below.

The epoxy resin (A) used in the present invention is not particularly limited in molecular structure and molecular weight as long as it is a compound having two or more epoxy groups in its molecule, and it is generally used as a material for sealing electronic parts. What is done can be widely included. Examples thereof include aromatic compounds such as phenol novolac type epoxy resin and bisphenol A type epoxy resin, aliphatic compounds such as cyclohexane derivative type, and epoxy compounds represented by the following general formula.

[0008]

[Chemical 1] (However, in the formula, R ¹ and R ² are a hydrogen atom or an alkyl group,
(n represents 0 or an integer of 1 or more, respectively)

[Chemical 2] (However, in the formula, R represents hydrogen or a methyl group.) These epoxy resins can be used alone or in combination of two or more kinds.

The para-alkyl modified phenolic resin (B) used in the present invention has two or more phenolic hydroxyl groups capable of reacting with the epoxy resin (A). The para-position-modified phenol resin is, for example, para-alkylphenol such as p-methylphenol or p-isobutylphenol, or p- (p- such as bisphenol A or bisphenol F).
It is a novolak type phenolic resin obtained by the reaction of (hydroxyphenyl) alkylphenol and formaldehyde. The para positions of these phenolic resins are blocked by the substituents of the raw material phenol, and the methylene bonds of the novolac are all in the α position.

Specific examples thereof include bisphenol A type novolac resin (Chemical formula 3) and alkyl-modified novolac phenolic resin (Chemical formula 4) represented by the following general formula.

[0011]

[Chemical 3] (However, in the formula, n represents 0 or an integer of 1 or more)

[Chemical 4] (However, in the formula, n represents 0 or an integer of 1 or more.) These para-position alkyl-modified phenol resins are used alone or in combination of two or more. Further, these para-alkyl-modified phenol resins may be mixed with a raw material phenol containing two or more hydroxyl groups, that is, p- (p-hydroxyphenyl) alkylphenol such as bisphenol A and bisphenol F. By mixing bisphenol A or the like, the fluidity and curability can be easily adjusted.

The blending ratio of the para-alkyl-modified phenolic resin (B) is such that the epoxy group (a) of the epoxy resin and the phenolic resin (mixed bisphenol A) are mixed.
It is desirable that the equivalent ratio [(a) / (b)] with the phenolic hydroxyl group (b) (including the above) be within the range of 0.5 to 2. If the equivalent ratio is less than 0.5 or exceeds 2,
In either case, the humidity resistance, heat resistance, molding workability, and electrical characteristics of the cured product deteriorate, which is not preferable. Further, from the viewpoint of discoloration, [(a) / (b)] is more preferably 0.5.
It is preferable to limit the range to 1.0.

As the inorganic filler (C) used in the present invention, it is general to use, for example, a combination of silica powder and titanium oxide, but it is also possible to use it alone, and further, alumina powder, silicon nitride. Powder, aluminum nitride powder, glass fiber, whiskers and the like can also be used in combination. The blending ratio of the inorganic filler is preferably 60 to 95% by weight based on the total resin composition. If the proportion is less than 60% by weight, the heat resistance and reliability will be poor, and if it exceeds 95% by weight, the dryness will be large and the moldability will be poor, making it unsuitable for practical use. The ratio of silica powder and titanium oxide is not particularly limited,
In consideration of practicality (whiteness), titanium oxide is preferably contained in an amount of about 10 to 50% of the inorganic filler. Further, the particle size of titanium oxide has a maximum particle size of 5 μm or less and an average particle size of 0.
It is preferably 2 to 1 μm.

The encapsulating resin composition of the present invention contains the above-mentioned (A) epoxy resin, (B) para-alkyl modified phenol resin and (C) inorganic filler as essential components. As long as it does not violate, and if necessary, for example, a brominated flame retardant represented by a brominated epoxy compound, a phosphorus flame retardant represented by a condensed phosphoric acid ester, a flame retardant such as an inorganic flame retardant and a flame retardant. Auxiliary agents, release agents such as natural waxes, synthetic waxes and esters, components for reducing stress such as elastomers, coloring agents such as carbon black, treatment agents for inorganic fillers such as silane coupling agents, Various curing accelerators and the like can be appropriately added and blended. Furthermore, an antioxidant such as HCA can be added or pre-added to a phenol resin or the like.

As a general method for preparing the encapsulating resin composition of the present invention as a molding material, the above-mentioned epoxy resin, para-alkyl modified phenolic resin, inorganic filler and other components are blended and a mixer is used. After the mixture is sufficiently homogeneously mixed by a method such as the one described above, it is further melt-mixed by a hot roll or mixed by a kneader, cooled and solidified, and then crushed to an appropriate size to obtain a molding material. When the molding material thus obtained is applied to sealing, coating, insulation, etc. of electronic parts or electric parts such as semiconductor devices, excellent properties and reliability can be imparted.

The electronic component sealing device of the present invention can be easily manufactured by sealing an electronic component semiconductor using the sealing resin obtained as described above. The most general method of sealing is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. The resin composition for encapsulation is heated and cured during encapsulation, and finally an electronic component encapsulation device encapsulating with the cured product of this composition is obtained. Curing by heating
It is desirable to heat it to 150 ° C. or higher to cure it. The electronic component to be sealed is not particularly limited to, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, a capacitor, an optical semiconductor, and the like, which are given as semiconductor elements.

[0017]

The epoxy resin composition for encapsulation and the electronic component encapsulating apparatus of the present invention have the object of using a para-position alkyl-modified phenol resin having a small amount of reactive hydrogen atoms at the α-position and the p-position as a resin component. The following characteristics can be obtained. That is, a para-alkyl-modified phenol resin having a small number of hydrogen atoms in the α-position and p-position can maintain a good appearance of an electronic component device while maintaining sufficient moisture resistance reliability and a low degree of discoloration of a cured product. it can.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In the following examples and comparative examples, “%” means “% by weight”.

Example 1 Cresol novolac type epoxy resin (epoxy equivalent 2
00) 13%, bisphenol A novolac type phenol resin (hydroxyl group equivalent 115) 6%, fused silica powder (average particle size 20 μm) 50%, titanium oxide (average particle size 0.3
μm) 25%, antimony trioxide 5% and carnauba wax 1%, and kneaded with a roll mill at room temperature.
Further, the mixture was kneaded at 90 to 95 ° C., and cooled and pulverized to produce a molding material.

The molding material thus produced was transfer-injected into a mold heated to 175 ° C. and cured to form a molded product (sealed product). This product was tested for hue, its change and hygroscopic property, and the results are shown in Table 1.

Example 2 Cresol novolac type epoxy resin (epoxy equivalent 2
00) 12%, a mixture of bisphenol A type novolak type phenolic resin and bisphenol A (hydroxyl equivalent 120 of the mixture) 7%, fused silica powder (average particle size 20 μ
m) 50%, titanium oxide (average particle size 0.3 μm) 25
%, Antimony trioxide 5% and carnauba wax 1
%, And kneaded with a roll mill at room temperature, and further 90
Kneading was performed at ˜95 ° C., and the mixture was cooled and ground to produce a molding material.

The molding material thus produced was transfer-injected into a mold heated to 175 ° C. and cured to form a molded product (sealed product). This product was tested for flammability and reliability, and the results are shown in Table 1.

Example 3 Cresol novolac type epoxy resin (epoxy equivalent 2
00) 12%, alkali-modified novolac type phenolic resin shown in Chemical formula 4 (hydroxyl equivalent 160) 7%, fused silica powder (average particle size 20 μm) 50%, titanium oxide (average particle size 0.1 μm) 25%, trioxide 5% of antimony and 1% of carnauba wax were mixed, kneaded by a roll mill at room temperature, further kneaded at 90 to 95 ° C., and cooled and ground to produce a molding material.

The molding material thus produced was transfer-injected into a mold heated to 175 ° C. and cured to form a molded product (sealed product). This product was tested for flammability and reliability, and the results are shown in Table 1.

Comparative Example 1 Cresol novolac type epoxy resin (epoxy equivalent 2
00) 13%, phenol novolac type phenol resin (hydroxyl group equivalent 105) 6%, fused silica powder (average particle size 20 μm) 50%, titanium oxide (average particle size 0.3 μm)
25%, antimony trioxide 5% and carnauba wax 1% were blended, kneaded by a roll mill at room temperature, further kneaded at 90 to 95 ° C., and cooled and ground to produce a molding material.

The thus-prepared molding material was transfer-injected into a mold heated to 175 ° C. and cured to form a molded product (sealed product). This product was tested for flammability and reliability, and the results are shown in Table 1.

[0027]

[Table 1] * 1: The molded product obtained by transfer molding at 175 ° C. for 2 minutes was placed in an oven at 175 ° C., and the change in hue was measured with a hue meter.

* 2: A test piece of 50 mmφ × 3 mm obtained by transfer molding for 2 minutes at 175 ° C. was used for 17 minutes.
After post-curing at 0 ° C for 8 hours, 127 ° C, 2.5 atm,
The moisture absorption treatment was performed for 24 hours, and the weight change was determined.

[0029]

As is clear from the above description and Table 1, the encapsulating resin composition of the present invention has excellent hygroscopic properties, and the cured product thereof has little discoloration. Therefore, by sealing an electronic component with this resin composition, discoloration of the appearance can be significantly reduced even when it is used for a long period of time.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI H01L 23/31 (56) Reference JP-A-7-268071 (JP, A) JP-A-11-181238 (JP, A) JP-A-62 -20521 (JP, A) JP-A-2-289615 (JP, A) JP-A-3-137119 (JP, A) JP-A-10-30049 (JP, A) JP-A-2000-109646 (JP, A) JP-A-11-152393 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 59/00-59/72 C08L 63/00-63/10 H01L 23/29 H01L 23 / 31

Claims (3)

(57) [Claims] 1. A para-positioned alkyl obtained by the reaction of (A) epoxy resin, (B) phenol substituted at the para-position with an alkyl group or para-hydroxyalkyl group and formaldehyde, and having a methylene bond only at the α-position. An inorganic filler consisting of a modified phenol resin and (C) silica powder and titanium dioxide is used as an essential component, and 60 to 9 of the (C) inorganic filler is added to the resin composition.
For sealing, containing 5% by weight
White resin composition. 2. The amount of titanium dioxide blended is that of the inorganic filler.
The amount is 10 to 50% by weight.
White resin composition for encapsulation. 3. The white resin composition for sealing according to claim 1 or 2.
The electronic parts are sealed by the cured product.
Electronic component encapsulation device to be used.