JP3035135B2 - Die bonding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonding material excellent in low stress, adhesiveness and low water absorption.

[0002]

2. Description of the Related Art In recent years, as semiconductor chips have become larger and packages have become thinner, the requirements for reliability of resin materials as peripheral materials have become stricter year by year. Among them, characteristics of a die bonding material for bonding a semiconductor chip to a lead frame are regarded as important factors for improving the reliability of a package. Particularly important in the reliability of the package is resistance to solder cracks against thermal stress during mounting. In order to improve this property, low stress, low water absorption,
High adhesion is required. However, a material satisfying all of these properties has not been known so far. For example, as a die bonding material, there is a material obtained by dispersing an inorganic filler in a polyamide resin, which is excellent in adhesiveness and low stress, but inferior in low water absorption, and in a cured product because a solvent is used. There are disadvantages that voids are easily left and high temperature is required for curing. On the other hand, there is a resin in which an inorganic filler is dispersed in an epoxy resin as another resin, but although it has excellent adhesiveness, it is slightly inferior in terms of low water absorption, and is also inferior in low stress property because the cured product is hard and brittle There was a problem.

[0003]

SUMMARY OF THE INVENTION The present invention, as a result of intensive studies to solve these problems, provides a die bonding material excellent in low stress, adhesion and low water absorption.

The present invention provides (A) an epoxy resin (a) represented by the formula (1) and a phenol (b) having two phenolic hydroxyl groups in the molecule in an equivalent ratio [ (B) hydroxyl equivalent / (a) epoxy equivalent]
It is a product obtained by reacting in excess of phenols (b), (B) an epoxy resin, (C) a curing agent, and (D) an inorganic filler.

[0004]

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[0005] The epoxy resin of the formula (1) used in the present invention has characteristics of low elastic modulus and low water absorption. R ₁ ,
R ₂ represents a divalent aliphatic group having 1 to 5 carbon atoms or a residue obtained by removing two hydrogen atoms from an aromatic group having 6 or more carbon atoms, and may be the same or different. R ₁ and R _{2 having} a divalent carbon number of 6 or more have not been industrialized. Among them, R ₁ and R ₂
Is preferably a propylene group. As an example of the reaction between the epoxy resin of the formula (1) and the phenol (b) used in the present invention, the epoxy resin (a) of the formula (1) and the phenol (b) have an equivalent ratio [hydroxy equivalent of (b)]. / Epoxy equivalent of (a)], an epoxy resin and a phenol (b) are mixed in excess of the phenol (b), a solvent is added if necessary, and the mixture is reacted at 100 ° C. or higher. The equivalent ratio is 1
To 5 are more preferable. When the equivalent ratio exceeds 5, the siloxane content decreases, and it becomes difficult to exhibit low stress properties as a die bonding material. Further, the epoxy resin of the formula (2) containing a siloxane unit having a long chain length from the formula (1) is also industrialized.

[0006]

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However, the epoxy resin having a long chain length of the formula (2) or the reaction product obtained by the method of the present invention using the formula (2) is excellent in low stress property, but has low adhesive strength, particularly hot strength. descend. In order to accelerate the reaction between the epoxy resin (a) and the phenols (b), a catalyst may be added as necessary. Examples of the catalyst include organic phosphines such as triphenylphosphine and tributylphosphine, organic borate salts thereof, and diaza compounds such as 1,8-diazabicycloundecene.

The phenols used in the present invention include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol F, tetramethyl bisphenol S, dihydroxydiphenyl ether, dihydroxybenzophenone, o-hydroxyphenol. , M-hydroxyphenol, p-hydroxyphenol, biphenol, tetramethylbiphenol, ethylidenebisphenol, methylethylidenebis (methylphenol), α-methylbenzylidenebisphenol, cyclohexylidenebisphenol, and the like. May be used.

Examples of the epoxy resin used in the present invention are not particularly limited. For example, bisphenol A, bisphenol F, diglycidyl ether obtained by the reaction of phenol novolak with epichlorohydrin, liquid at room temperature, vinylcyclohexene dioxide , Dicyclopentadiene oxide, alicyclic epoxy such as alicyclic diepoxide-adipate, and the like.

[0010] The curing agent of the present invention is not particularly limited as long as it does not impair the shelf life of the die bonding material. Examples thereof include acid anhydrides such as hexahydrophthalic anhydride, methylhydrophthalic anhydride, and nadic anhydride, polyphenols such as novolak-type phenol resin, and amine compounds such as imidazole and dicyandiamide. The mixing ratio of the reaction product, epoxy resin and curing agent is not particularly limited, but the ratio of epoxy group equivalent / active group equivalent reacting with epoxy group is 1 to 10
And the reaction product in the total weight of the three is preferably at least 30% by weight. If the equivalent ratio exceeds 10 or the reaction product is less than 30% by weight, the low stress property as the die bonding material is impaired.

Examples of the inorganic filler used in the present invention include insulating fillers such as calcium carbonate, silica, and alumina, and conductive fillers such as silver powder, gold powder, nickel powder, and copper powder. Good. Furthermore,
These particles have a particle size of 50 μm to prevent needle clogging.
The following are preferred.

According to the present invention, a resin having an appropriate viscosity is obtained as a die bonding material by pre-reacting an epoxy resin containing a low-chain-length siloxane unit represented by the formula (1) with a phenol. Chip bleeding and outgassing of components and contamination of the periphery thereof can be extremely reduced. Further, since the epoxy resin of the formula (1) is a low-chain-length siloxane unit, the fluidity at the time of heating is suppressed to some extent, and the decrease in adhesive strength at the time of heating is reduced. Furthermore, the epoxy resin of the formula (1) is used alone,
Alternatively, the die bonding material in which the epoxy resin of the formula (1) is mixed with another epoxy resin has a disadvantage that outgassing or bleeding occurs at the time of curing, thereby contaminating the periphery of the semiconductor. The resin composition of the present invention is pre-mixed with a reaction product, an epoxy resin, a curing agent and an inorganic filler, and if necessary, additives such as a curing accelerator, a pigment, a dye, an antifoaming agent, and a solvent. The mixture can be manufactured by kneading the mixture, obtaining a paste, and defoaming in vacuo.

Production Example 1 of Reaction Product 100 g of bisphenol F (hydroxy equivalent: 100) and 90 g of epoxy resin of formula (3) (epoxy equivalent: 181)
Was added with 0.5 g of triphenylphosphine as a catalyst, and the mixture was reacted at 180 ° C. for 2 hours. This product is referred to as reaction product (1).

[0014]

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Production Example 2 of reaction product 110 g of resorcinol (hydroxyl equivalent 55), formula (3)
To 180 g of the epoxy resin was added 0.5 g of triphenylphosphine as a catalyst and reacted at 180 ° C. for 2 hours. This product is referred to as reaction product (2). Production Example 3 of Reaction Product 0.5 g of triphenylphosphine was added to 100 g of bisphenol F and 165 g of an epoxy resin of formula (4) (epoxy equivalent 330), and reacted at 180 ° C. for 2 hours. This product is referred to as reaction product (3).

[0016]

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Hereinafter, the present invention will be described specifically with reference to Examples. Example 1 70 g of bisphenol F epoxy resin (epoxy equivalent 170) (hereinafter referred to as BPFEP) as an epoxy resin,
30 g of t-butylphenylglycidyl ether (hereinafter referred to as TGA) as a diluent, 1 g of dicyandiamide (hereinafter referred to as DDA) as a curing agent, 2-phenyl-4-
2 g of methylimidazole (referred to as 2E4MI), 150 g of the reaction product (1), and 830 g of flake silver powder having an average particle diameter of 3 μm were mixed and kneaded with a three-roll mill to prepare a die bonding material. Using this die bonding material, a 2 × 2 mm square silicon chip is placed on a silver-plated copper frame for 200 times.
The composition was cured and adhered at 60 ° C. for 60 minutes, and the adhesive force at 300 ° C. was measured with a push-pull gauge. Similarly, 15 × 6 ×
A silicon chip of 0.3 mm (thickness) is cured and adhered to a silver-plated copper frame having a thickness of 50 μm at 200 ° C. for 60 minutes, and the longitudinal direction of the chip is measured using a surface roughness meter as a measure of low stress. The maximum value of the displacement in the direction was determined. Further, the elastic modulus of the cured product of the die bonding material (cured at 200 ° C. for 60 minutes) and the saturated water absorption at 85 ° C. and 85% RH were measured. Further, the bleeding property was examined. Table 1 shows the evaluation results.

Examples 2 to 4 According to the composition shown in Table 1, the die bonding material was adjusted in the same manner as in Example 1, and the same test as in Example 1 was performed. Table 1 shows the measurement results.

Comparative Examples 1 to 3 According to the composition shown in Table 1, a die bonding material was prepared in the same manner as in Example 1, and the same test as in Example 1 was performed. Table 1 shows the measurement results.

[0020]

[Table 1]

[0021]

Industrial Applicability The present invention is an industrially useful die bonding material which is excellent in low stress, adhesiveness and low water absorption and has no bleed during curing.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI H01L 21/52 H01L 21/52 E (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 63/00-63 / 10 C08G 59/20-59/30 C09J 163/00-163/10 H01L 21/52

Claims (1)

(57) [Claims] 1. An equivalent ratio of (A) an epoxy resin (a) represented by the formula (1) to a phenol (b) containing two phenolic hydroxyl groups in a molecule [hydroxyl equivalent of (b) /
(A) epoxy equivalent], a product obtained by reacting in excess of phenol (b), (B) an epoxy resin, (C) a curing agent, and (D) an inorganic filler as essential components. Die bonding material. Embedded image