JP3456911B2 - Liquid sealing resin composition and semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid encapsulating resin composition having excellent fluidity and reliability.

[0002]

2. Description of the Related Art With the recent increase in size of semiconductor chips and diversification of packages, demands for reliability of resin materials as peripheral materials have become stricter year by year. Conventionally, a package in which a semiconductor chip is adhered to a lead frame and sealed with a molding resin has been the mainstream, but packages such as a ball grid array (BGA) have been increasing due to the limit of increasing the number of pins. The BGA is sealed with a mold resin or a liquid resin. Furthermore, since it is mounted by the surface mounting method, the sealing material needs to have so-called solder crack resistance.

Important factors for solder crack resistance are (1)
Adhesiveness to an adherend, its moisture resistance reliability, and (2) wide encapsulation resin linear expansion coefficient (α1) range (high Tg). Furthermore, it is important that there are few ionic impurities and that they have excellent properties in the thermal shock test. Also, in many BGAs, the semiconductor element is bonded to the cavity of the substrate, and the substrate and the element are electrically joined by wire bonding, and the distance between the wires is very narrow, so the liquid resin needs to have excellent fluidity. Is.

As resins satisfying these conditions, liquid epoxy resins, liquid acid anhydrides, and compositions containing spherical silica filler as a main component have been commercialized. It has high Tg due to acid anhydride curing, low linear expansion coefficient due to high filler filling due to low resin viscosity, and excellent fluidity, but on the other hand, it has a fatal defect of poor water resistance. It was Liquid epoxy resin, liquid aromatic amine,
A composition containing a spherical silica filler as a main component has also been proposed. However, although these liquid encapsulating resins are excellent in water resistance and solder crack resistance, they have a low Tg, and there is a problem that cracks occur on the surface of the cured resin particularly in a thermal shock test.

For other liquid thermosetting resins, liquid cyanate type is considered. Although this resin system provides a cured product having a high Tg, it has drawbacks such as inferior moisture-resistant adhesiveness and inferior fluidity, and has not been put to practical use for encapsulating semiconductors such as BGA.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a liquid encapsulating resin composition having excellent fluidity and reliability as a result of extensive studies to solve these problems.

[0007]

Means for Solving the Invention Equation (1) and Equation (2)
And / or 0.15 to 0.9 parts by weight of the metal complex catalyst (B) with respect to 100 parts by weight of the liquid cyanate ester (A) represented by the formula (3), the formula (4)
Alkoxysilane compounds (C) 1 to 15
It is a liquid encapsulating resin composition comprising parts by weight and an insulating inorganic filler. Furthermore, in the liquid cyanate ester, the compound of formula (2)
And / or the cyanate ester represented by the formula (3) is contained in an amount of 15 to 30% by weight, the insulating inorganic filler is 60 to 80% by weight based on the total liquid resin, and the shape of the insulating inorganic filler is spherical. The average particle size of the insulating inorganic filler is 0.5 μm to 12 μm, and the maximum particle size is 70 μm or less.

[0008]

[Chemical 1]

[Chemical 2] Further, it is a semiconductor device obtained by encapsulating a semiconductor with the above liquid encapsulating resin composition, and preferably the semiconductor device is a ball grid array.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The cyanate ester (A) used in the present invention comprises formula (1) and formula (2) and / or formula (3). Furthermore, the cyanate ester represented by the formula (2) and / or the formula (3) is added to all cyanate esters.
It is desirable to contain 5 to 30% by weight.

This is because the cyanate ester represented by the formula (1) used in the present invention is a liquid having a low viscosity and is suitable for a sealing resin material, but the cured product is slightly inferior in moisture resistance. On the other hand, the cyanate ester represented by the formulas (2) and (3) has an alkyl in the molecule and has moisture resistance. The cyanate ester represented by the formula (2) used in the present invention is 4,4′-methylidene bis [2,6-dimethylphenylene cyanate], 4,4 ′-(1-methylethylidene) bis.
[2-Methylphenylene cyanate], 4,4 '-(1-methylethylidene) bis [2,6-dimethylphenylene cyanate], 4,4'-methylenebis [2-methylphenylene cyanate], 4,4'-( 1-methyl-ethylidene) bis [2- (1,1-
Dimethylethyl) phenylene cyanate] and the like, and examples of the cyanate ester represented by the formula (3) include phenol novolac type cyanate ester and cresol novolac type cyanate ester. By using this material, reliability of liquid sealing mounting and reliability of moisture resistance,
Liquidity can be greatly improved.

Here, the cyanate ester represented by the formula (2) and / or (3) contained in all the cyanate esters is 1
If it is less than 5% by weight, the adhesion after moisture absorption is low, and if it is more than 30% by weight, the product viscosity increases and the fluidity decreases.
For the purpose of preventing crystallization of the product during freezing storage so that the viscosity does not exceed the allowable range, these cyanate esters may be preheated and reacted at about 10 to 30% by weight. . Further, other cyanate resin synthesized from a phenol compound can be added within a range not departing from the effects of the present invention. The addition amount thereof is preferably 30% by weight or less based on the entire cyanate resin.

Generally, a compound having at least two cyanate groups in one molecule is easily crosslinked by a trimerization reaction by heating in the presence of a metal complex to give a cured resin product having a high Tg. Examples of the metal complex catalyst (B) include metal naphthenates such as cobalt, zinc, iron, copper, chromium, manganese, nickel and titanium, acetylacetonates, salts of their derivatives, and various carboxylate alkoxides. There are organic acid salts, etc., which may be used alone or in combination. The amount of addition is 10 cyanate resins.
It is 0.15 to 0.9 parts by weight with respect to 0 parts by weight. If it is less than 0.15 parts by weight, the reaction promoting effect is low,
The curing time is long and the productivity is poor. On the other hand, if it is more than 0.9 parts by weight, the pot life and pot life of the product (shelf life) are impaired.

Next, as the alkoxysilane compound (C) used in the present invention, a compound which hardly interacts with or reacts with the cyanate resin is applied. This is because when there is a functional group that interacts with or reacts with a cyanate group (for example, glycidyl group, mercapto group, amino group, isocyanate group, chlorine, hydroxyl group, etc.), the fluidity of the liquid resin is extremely lowered, This is because the fluidity does not improve even when heated.

Therefore, examples of the alkoxysilane used in the present invention include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri- (β-methoxyethoxy) silane and β- (3,4epoxycyclohexyl) ethyl. Trimethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldiethoxysilane, γ-acryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, Examples thereof include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, and γ-methacryloxypropyltriethoxysilane, which may be used alone or in combination.

The amount of alkoxysilane added is from 1 to 15 parts by weight per 100 parts by weight of the total cyanate resin. If it is less than 1 part by weight, adhesiveness will not be expressed,
On the other hand, if the amount is more than 15 parts by weight, excess alkoxysilane increases, causing bleeding, voids, outgassing, etc., which is not preferable.

Insulating inorganic filler (D) used in the present invention
Examples of include calcium carbonate, silica, alumina, aluminum nitride, and the like. Silica particles are preferable in terms of reliability, heat dissipation, and cost, and low radiation is more preferable. The shape may be spherical, crushed, flake-shaped, or the like, but spherical is preferable because the linear expansion coefficient can be reduced by increasing the filling amount of the filler. The amount of addition is required to be 60 to 80% by weight of the total liquid encapsulating resin composition in order to maintain the properties (moisture resistance, workability, etc.) as an encapsulating resin. If it is less than 60% by weight, the above-mentioned effect of reducing the coefficient of linear expansion is small, and if it exceeds 80% by weight, the viscosity of the resulting composition becomes too high and the flow characteristics deteriorate, which is not preferable. When added, they may be used alone if mixed within the above range, or may be mixed to have multimodal particle size distribution.

In addition to the above essential components, the liquid encapsulating resin composition of the present invention may optionally contain additives such as epoxy resin and various liquid rubbers. Further, a catalyst or a curing agent for promoting the reaction with the epoxy resin, a diluent,
Additives such as pigments, coupling agents, flame retardants, leveling agents, defoamers and the like may be used. The liquid sealing resin is
For example, each component, additives, etc., three rolls, two heat rolls,
It is manufactured by dispersing and kneading with a blade type mixer and defoaming under vacuum.

[0018]

EXAMPLES The present invention will be specifically described with reference to Examples. <Examples 1 and 2 and Comparative Examples 1 to 4> Weighed according to the formulation shown in Table 1, kneaded and dispersed with a three-roll mill, and then vacuum defoaming treatment was performed to produce a liquid encapsulating resin. However, Comparative Example 4 is a current epoxy resin-based liquid encapsulating resin, in which 100 parts by weight of a phenol novolac type epoxy resin is added with 39 parts by weight of an aromatic diamine compound and 10.8 parts of γ-glycidoxypropyltrimethoxysilane. The formulation was added with parts by weight.

Next, the following substitute characteristics were evaluated in order to grasp the characteristics of the resin. (1) Viscosity measurement: The viscosity after standing for 72 hours at 25 ° C was measured with an E-type viscometer manufactured by Toki Sangyo Co., Ltd., and the value was taken as the viscosity of the material. At the same temperature, the ratio at 0.5 and 2.5 revolutions of the viscometer was taken as the thixotropy. (2) Adhesive strength: Solder resist (PSR-4000 / Taiyo Ink Co., Ltd.) on a BT resin substrate as an organic substrate
A liquid sealing resin is applied to the surface on which CA-40) is formed, and a 6 × 6 × 0.38 mm square silicon chip is placed thereon and cured and adhered at 150 ° C. for 180 minutes.
The die shear strength in seconds was measured by BT100 manufactured by DAGE. Further, the same test piece was subjected to a moisture absorption treatment at a humidity of 85% and a temperature of 85 ° C. for a maximum of 72 hours, and similarly, the die shear strength was measured to obtain the adhesion after the moisture absorption treatment.

(3) Fluidity: 14.5 as an organic substrate
Using a glass epoxy substrate with a cavity (A) of x14.5x0.5mm plated with gold, (A)
Then, a certain amount of liquid resin was applied to the center of (A) so that it could be fully filled after flowing as droplets. Put it in (1) room temperature 5
After allowing to stand for 5 minutes, (2) 5 on a hot plate at 80 ° C.
After allowing to stand for (3) in a curing furnace at (3) 150 ° C. for 180 minutes, the results of (1) to (3) were combined and the wet spreadability of the liquid resin was observed to evaluate the fluidity. .

Table 1 shows the above measurement results.

[Table 1]

As shown in Table 1 above, in the examples, the adhesive force to the adherend was remarkably increased, and the adhesive force after moisture absorption was at the same level as that of the existing liquid resin. In addition, since Examples 1, 2 and 3 are cyanate ester liquid resins, they exhibited a very high glass transition temperature. Regarding the fluidity, in Example 1, a certain degree of fluidity was exhibited, but in Example 2, a very good fluidity was exhibited by the combination of the alkoxyxylan compounds. In addition, since Example 1 and Example 2 contain an alkoxysilane compound,
No significant decrease in the adhesiveness after moisture absorption was observed, and even after 72 hours, the value was equal to or higher than the practically used epoxy resin-based liquid sealing resin shown in Comparative Example 4.

On the other hand, in Example 3, since the phenol novolac type cyanate ester was used, the adhesion and the glass transition temperature were high, but the viscosity and thixotropy were high, and the flowability was inferior to that of Examples 1 and 2, but the alkoxysilane type was used. Both adhesion and fluidity were improved as compared to Comparative Example 2 in which no compound was used. In Comparative Example 1, since the alkoxysilane-based compound is not used, the Tg is high, but the decrease in adhesion after moisture absorption is larger than the others, and it is already dramatically reduced 24 hours after moisture absorption, resulting in poor fluidity. It was Further, in Comparative Example 3, since an alkoxysilane having a glycidyl ether unit was used, the strength was high, but the viscosity and thixotropy were high and the fluidity was poor, and it was not suitable for a liquid resin. Comparative Example 4
Then, although it is an epoxy resin liquid resin, it is inferior to those of Examples 1 and 2 in terms of adhesion and Tg.

[0024]

Industrial Applicability By encapsulating with the liquid mold resin of the present invention, high-performance semiconductor encapsulation having high adhesion, high thermal properties and high fluidity can be achieved, which is a great industrial advantage.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI H01L 23/29 H01L 23/30 R 23/31 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 79/00 -79/08 C08K 3/00-13/08 C08G 73/00-73/26

Claims (7)

(57) [Claims] 1. Metal complex catalyst (B) 0.15 with respect to 100 parts by weight of at least two or more liquid cyanate esters (A) represented by formula (1) and formula (2) and / or formula (3). To 0.9 parts by weight, 1 to 15 parts by weight of the alkoxysilane compound (C) represented by the formula (4), and an insulating inorganic filler. [Chemical 1] [Chemical 2] 2. A liquid having the formula (2) in the liquid cyanate ester.
The liquid encapsulating resin composition according to claim 1, wherein the cyanate ester represented by the formula (3) is contained in an amount of 15% by weight to 30% by weight. 3. The liquid encapsulating resin composition according to claim 1, wherein the insulating inorganic filler is 60 to 80% by weight based on the total liquid resin. 4. The liquid encapsulating resin composition according to claim 1, wherein the insulating inorganic filler has a spherical shape. 5. The average particle diameter of the insulating inorganic filler is 0.
The liquid encapsulating resin composition according to claim 1, which has a maximum particle size of 5 μm to 12 μm and a maximum particle size of 70 μm or less. 6. A semiconductor device obtained by encapsulating a semiconductor with the liquid encapsulating resin composition according to claim 1, 2, 3, 4 or 5. 7. The semiconductor device according to claim 6, wherein the semiconductor is a ball grid array.