JP2705519B2 - Liquid epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid epoxy resin composition, for example, a liquid epoxy resin composition for encapsulating a semiconductor chip or the like.

[0002]

2. Description of the Related Art When a semiconductor element is mounted by spot sealing, a liquid epoxy resin composition is generally used. Since a liquid epoxy resin composition of this kind requires a proper fluidity, the curable resin component contained in the composition must have a low molecular weight. Therefore, the crosslinked density of a cured product obtained by curing the resin component is lower than that of a cured epoxy resin molding material molded using a mold, and there is a problem in moisture resistance.

Further, for example, when a liquid epoxy resin composition is spot-sealed on one side of a flexible wiring board made of a polyimide film to form a resin sealing layer, the characteristic of the flexible wiring board that is used by bending is used. When a typical use mode is adopted, there is a problem that the resin sealing layer separates from the flexible wiring board unless the resin sealing layer follows the bending of the flexible wiring board. That is, the liquid epoxy resin composition is required to have improved adhesive strength to the polyimide film and flexibility.

Conventionally, this type of sealing material has been disclosed in
As disclosed in Japanese Patent No. 249526, a novolak-type phenol resin having an acid anhydride and an allyl group as a curing agent, and a liquid epoxy resin composition containing a polyorganosiloxane for imparting flexibility are known. But,
The above-mentioned problem has not been solved.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a liquid epoxy resin composition suitable for forming a resin sealing layer by spot sealing. In particular, it is an object of the present invention to provide a liquid epoxy resin composition which imparts moisture resistance and flexibility and has an increased adhesive strength to a polyimide film.

[0006]

The liquid epoxy resin composition of the present invention contains a liquid epoxy resin as a matrix resin, a liquid acid anhydride and an allylated phenol novolak as a curing agent, and further comprises a flexibility-imparting agent. In a liquid epoxy resin composition containing an epoxy-modified polyorganosiloxane as the above, the allylated phenol novolak is contained in an amount of 10.7 to 30.0% by weight based on the total amount of the liquid compound, and the epoxy-modified polyorganosiloxane is contained in the liquid compound. Is contained in an amount of 5.0 to 20.0% by weight based on the total amount of

[0007]

According to the liquid epoxy resin composition of the present invention, the liquid epoxy resin composition contains a liquid epoxy resin as a matrix resin, a liquid acid anhydride and an allylated phenol novolak as a curing agent, and an epoxy-modified polyorgano resin as a flexibility-imparting agent. In a liquid epoxy resin composition containing siloxane, the allylated phenol novolak is contained in an amount of 10.7 to 30.0% by weight based on the total amount of the liquid compound, and the epoxy-modified polyorganosiloxane is contained in the liquid compound based on the total amount of the liquid compound. Since it is contained in an amount of 5.0 to 20.0% by weight, the liquid epoxy resin composition is suitable for forming a resin sealing layer by spot sealing. And the adhesive strength to the polyimide film can be increased.

Hereinafter, the present invention will be described in detail. The matrix resin constituting the liquid epoxy resin composition of the present invention is limited to the liquid epoxy resin. This liquid epoxy resin is an epoxy resin having two or more epoxy groups in one molecule, for example, bisphenol A type epoxy resin, novolak type epoxy resin, halogenated epoxy resin, glycidyl ester type epoxy resin, etc. Can be

As a curing agent for the above liquid epoxy resin,
A liquid acid anhydride and an allylated phenol novolak are used in combination. As the acid anhydride, various phthalic anhydride compounds are used, but they must be liquid compounds. As an example of a typical compound, methyl hexahydrophthalic anhydride or the like is used.

[0010] The liquid acid anhydride is involved in increasing or decreasing the viscosity which affects the fluidity of the liquid epoxy resin composition. That is, if the acid anhydride is excessively increased, the viscosity of the liquid epoxy resin composition decreases, and as a result, when the liquid epoxy resin composition is spot-sealed on the flexible wiring board, the liquid epoxy resin composition flows over a desired application area. When the viscosity increases, conversely, sealing at the spot becomes difficult,
The unreacted acid anhydride remaining in the cured product undergoes a hydration reaction, and inhibits the moisture resistance of the cured product.

Further, in order to increase the adhesive strength to a flexible wiring board made of a polyimide film, the amount of phenol novolak having a hydroxyl group having a higher chemical bonding force with the polyimide than the ester group of the acid anhydride is increased. The viscosity of the resin composition tends to increase, and as a result, as described above, it affects the difficulty of spot sealing.
That is, the acid anhydride used as the curing agent and the liquid allylated phenol novolak used in combination with the acid anhydride are limited in terms of both the spot sealing property and the moisture resistance of the liquid epoxy resin composition. That is, the allylated phenol novolak is used in an amount of 10.7 to 30.0 with respect to the total amount of the reactive liquid compound constituting the liquid epoxy resin composition.
Limited to weight percent. The reason is that when the amount of the allylated phenol novolak is less than 10.7% by weight, the adhesive strength to the flexible wiring board made of a polyimide film is weak. This is because it is necessary to increase the amount of the substance, and as a result, the moisture resistance deteriorates.

Here, the reactive liquid compound includes not only an epoxy resin of a matrix resin, a curing agent and a flexibility-imparting agent having the following reactivity but also, for example, a reactive diluent, and optionally contains a reactive diluent. Fillers used, for example,
Inorganic particles such as silica, calcium carbonate, and aluminum hydroxide, or substances that do not participate in the curing reaction such as fibrous substances such as glass fibers, asbestos fibers, pulp fibers, synthetic fibers, and ceramic fibers are excluded.

Further, the liquid epoxy resin composition of the present invention is characterized in that it contains a polyorganosiloxane having an epoxy group in order to impart flexibility to the cured product. This polyorganosiloxane is provided with flexibility only when it is limited to 5.0 to 20.0% by weight based on the total amount of the reactive liquid compound. That is, if an epoxy group is not introduced into the polyorganosiloxane, the matrix resin lacks compatibility with the epoxy resin, causing a phenomenon of separation. As a result, the flexibility of the cured product varies.
Furthermore, if this epoxy-modified polyorganosiloxane is less than 5.0% by weight, flexibility is not imparted to the cured product, and if it exceeds 20.0% by weight, adhesive strength to polyimide and moisture resistance are reduced. It is.

Further, the liquid epoxy resin composition of the present invention is characterized in that, in addition to the above liquid epoxy resin composition, silica surface-treated with dimethylsiloxane is added as a thixotropic agent. The thixotropy is imparted only when the amount of the thixotropy-imparting agent is limited to 0.2 to 2.0% by weight of the total amount of the liquid epoxy resin composition. That is, the above-mentioned moisture resistance and flexibility can be imparted, and furthermore, the thixotropy can be imparted while maintaining the adhesive strength to the polyimide film, and the thixotropy can improve the swellability. When the amount of the thixotropy-imparting agent is less than 0.2% by weight, the thixotropy is not imparted. is there.

As for the addition of the thixotropy-imparting agent, for example, TAB (Tape Automated Bond) is used.
ing) Since the element needs a sealing property of high fluidity for lead connection, it is not necessary to add a thixotropy-imparting agent to form the resin sealing layer of the TAB element by spot sealing. Or COF (Chip on Film)
Since the element needs a sealing property of a swelling property for wire connection, it is preferable to add a thixotropy-imparting agent in order to form the resin sealing layer of the COF element by spot sealing. As described above, the thixotropy-imparting agent is added in order to improve the sealing property, that is, the swelling property.

If necessary, a bromo compound,
Flame retardants such as chloro compounds and phosphorus compounds, defoamers such as silicon compounds, coloring agents such as carbon black and titanium oxide, silane coupling agents, and coupling agents such as titanate coupling agents can be used. . If necessary, the surface of the filler may be surface-treated with a coupling agent.

[0017]

【Example】

Examples 1 to 9 and Comparative Examples 1 to 4 Based on the blending tables of Tables 1 and 2, the ingredients were blended, mixed,
The mixture was kneaded and defoamed to obtain a liquid epoxy resin composition. Epoxy equivalent of 17 as matrix resin epoxy resin
5. A bisphenol A type epoxy resin having a viscosity of 10,000 CPS and shown in the following (Chemical Formula 1) was used.

[0018]

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As a curing agent for the above liquid epoxy resin,
An acid anhydride and an allylated phenol novolak are used in combination. As the acid anhydride, the hydroxyl equivalent is 168 and the viscosity is 6000 CPS.
Allylated phenol novolak was obtained with a hydroxyl equivalent of 142 and a viscosity of 3000.
The one shown in the following (Chemical Formula 2) having a weight average molecular weight of 690 and OCPS was used.

[0020]

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An organosiloxane is used as the flexibility-imparting agent, and an epoxy equivalent of 60 in the organosiloxane is used.
An epoxy-modified polyorganosiloxane represented by the following (Chem. 3) having 0, a viscosity of 190 CPS and an epoxy group in a side chain having a molecular weight of 3000 was used.

[0022]

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As the filler, spherical fused silica having an average particle size of 15 μm was used. As the curing accelerator, an imidazole-based 2,4-diamino-6 {2'-methylimidazolyl- (1) '} ethyl-s-triazine / isocyanuric acid adduct was used.

Further, as the thixotropy imparting agent added in Examples 6 to 9, hydrophobic ultrafine silica particles having an average particle diameter of 15 μm and having the surface dimethylated with dimethylsiloxane as shown in the following (Formula 4) Was used.

[0025]

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[0026]

[Table 1]

[0027]

[Table 2]

In Tables 1 and 2, the unit of the component composition is
Parts by weight. The performances of the liquid epoxy resin compositions of Examples 1 to 9 and Comparative Examples 1 to 4 were as shown in Tables 3 and 4 below. The viscosity was measured using a B-type rotational viscometer.
The peel adhesion strength was measured as PS at ° C. and evaluated for flexibility. In this measurement, the liquid epoxy resin composition was applied between two polyimide films having a width of 20 mm and cured to form a test piece. One of the polyimide films constituting the test piece was pulled left and the other was pulled right. The unit of the peel adhesive strength is g / 20 mm. The appearance and fluidity of the cured product were obtained by evaluating the spread of the resin when 1 g of the resin was applied on a copper foil and cured. The curing conditions were 15 minutes, 13
After maintaining at 0 ° C., the mixture was cured at 160 ° C. for 3 hours. ◎ indicates that resin 1 g was dropped on the copper foil and the spread was the largest, 、 was intermediate between ◎ and △, and △
Indicates that the spread was small, and x indicates that the spread was almost nonexistent. The swelling property is to apply 0.6 g of the liquid epoxy resin composition on the polyimide film,
The composition was cured at 100 ° C. for 1 hour, and the swell height was measured. ◎ indicates that the swell height is 3.0 mm or more, ○ indicates that the swell height is 2.0 mm or more to less than 3.0 mm, and Δ indicates that the swell height is 1.5 mm or more to 2 mm. Less than 0.0 mm, x
Has a swell height of less than 1.5 mm. A PCT test was performed as moisture resistance evaluation. This was performed by heating at 121 ° C. and 2 atm using a chip-mounted element, and measuring the time until a conduction failure due to cutting of the semiconductor circuit occurred. The device mounted with this chip has a chip size of 4 × 4 mm in Examples 1 to 5 and Comparative Examples 1 to 4,
Test TAB device with 61 leads, 5 on the chip
Example 6 A 2 μm, 10 μm 2 aluminum pattern resistor was prepared and used without passivation.
Test CO with chip size 2 × 3mm
Two 5 μm and 10 μm two aluminum pattern resistors were formed on the chip with the F element, and those without passivation were used.

[0029]

[Table 3]

[0030]

[Table 4]

From the results shown in Tables 3 and 4, when Examples 1 to 9 are compared with Comparative Examples 1 to 4, the viscosity is low, the peel adhesion strength is high, and the appearance of the cured product is high. The results also show that the fluidity was excellent and the results of the PCT test were also improved. Furthermore, in the swelling property, when Examples 6 to 9 and Examples 1 to 5 and Comparative Examples 1 to 4 are compared, it is improved by adding the thixotropic agent while maintaining other evaluation values. You can see that there is. From the above, it was found that the moisture resistance and the adhesiveness were improved, and the flexibility was high, which was suitable for forming the resin sealing layer by spot sealing.

[0032]

According to the liquid epoxy resin composition of the present invention, it contains a liquid epoxy resin as a matrix resin, a liquid acid anhydride and an allylated phenol novolak as a curing agent, and an epoxy-modified as a flexibility-imparting agent. In a liquid epoxy resin composition containing a polyorganosiloxane, the allylated phenol novolak is contained in an amount of 10.7 to 30.0% by weight based on the total amount of the liquid compound, and the epoxy-modified polyorganosiloxane is contained in the entire amount of the liquid compound. A liquid epoxy resin composition suitable for forming a resin sealing layer by spot sealing because it contains 5.0 to 20.0% by weight, particularly, moisture resistance, flexibility, and a polyimide film. Adhesive strength to a flexible wiring board made of

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C08L 63/00 C08L 63/00 Z H01L 23/29 H01L 23/30 R 23/31

Claims (2)

(57) [Claims] 1. A liquid epoxy resin composition containing a liquid epoxy resin as a matrix resin, a liquid acid anhydride and an allylated phenol novolak as a curing agent, and an epoxy-modified polyorganosiloxane as a flexibility-imparting agent. In the above, the allylated phenol novolak is contained in an amount of 10.7 to 30.0% by weight based on the total amount of the liquid compound, and the epoxy-modified polyorganosiloxane is contained in an amount of 5.0 to 20.0% by weight based on the total amount of the liquid compound. Liquid epoxy resin composition characterized by containing. 2. The liquid epoxy resin composition according to claim 1, wherein
2. The liquid epoxy resin according to claim 1, further comprising, as a thixotropic agent, 0.2 to 2.0% by weight of silica surface-treated with dimethylsiloxane based on the total amount of the liquid epoxy resin composition. Composition.