JP2985701B2 - 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 used, for example, as a semiconductor encapsulant.

[0002]

2. Description of the Related Art Conventionally, epoxy resin compositions have been used in various applications in the electric and electronic fields because of their excellent electrical performance and adhesive strength. It is known that an epoxy resin composition uses various curing agents at the time of curing, and that the performance of a cured product greatly differs depending on the type of the curing agent, and the curing agent is properly used depending on the application. For example, in applications of adhesives and laminates, adhesion is the most important, so long-term water resistance, inferior in pot life,
An amine-based curing agent having excellent adhesiveness is used, and an acid anhydride system which is inferior in adhesiveness and long-term water resistance but is excellent in electrical performance and low viscosity is used for a casting material. In sealing material applications, phenol-based curing agents are used because they have high viscosity but are excellent in balance among adhesiveness, water resistance, electrical performance, and the like.

[0003] Conventionally, solventless adhesives, sealing materials,
As a curing agent for a liquid epoxy resin composition such as a paint, an amine curing agent and an acid anhydride are known. Amine-based curing agents and acid anhydride-based curing agents are easily liquefied, but have the following problems. That is, when an amine-based curing agent is used, the tertiary amine structure is present in the crosslinked structure of the cured product, so that the hygroscopicity is increased. When an acid anhydride curing agent is used, the ester structure in the crosslinked structure of the cured product is liable to be chemically hydrolyzed, resulting in poor long-term water resistance, and in addition to the acid anhydride groups of the curing agent and the epoxy resin of the epoxy resin. Since the alcoholic hydroxyl group contributing to adhesion is hardly produced as a by-product due to the reaction with the group, the cured product has poor adhesion. On the other hand, phenolic curing agents represented by phenol novolak resins are:
Although excellent in terms of adhesiveness, water resistance, electrical performance, etc., they are not generally used for liquid epoxy resin compositions because of difficulty in liquefaction.

[0004] Since recent electronic components tend to be high density and thin, a bare chip is mounted from a conventional transfer molded package and sealed with a liquid sealing material.
So-called chip-on-board (COB) and TAB (Tape A
utomated bonding). As described above, a liquid epoxy resin composition using an amine-based or acid anhydride-based curing agent occupies the mainstream as a conventional liquid sealing material due to the limitation of viscosity. However, the liquid encapsulant composed of a liquid epoxy resin composition using an amine-based or acid anhydride-based curing agent is more comprehensive than a transfer molding material composed of a solid epoxy resin composition using a phenol-based curing agent. Poor reliability. Therefore, it is strongly desired to improve the reliability of the liquid sealing material.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to form a resin sealing layer by spot sealing with low viscosity and good handleability. It is an object of the present invention to provide a liquid epoxy resin composition which is suitable for a liquid epoxy resin composition, which is excellent in pot life, and which can obtain a highly reliable cured product excellent in moisture resistance, heat resistance, electric characteristics and the like.

[0006]

The liquid epoxy resin composition according to the first aspect of the present invention comprises an epoxy resin having two or more glycidyl groups in a molecule, a curing agent, a curing accelerator, and a filler. The contained epoxy resin composition at room temperature is characterized in that the curing agent contains an allylated bisphenol compound and a compound having three or more phenolic hydroxyl groups in the molecule.

The liquid epoxy resin composition of the invention according to claim 2 is characterized in that the compound having three or more phenolic hydroxyl groups in the molecule is pyrogallol.

A liquid epoxy resin composition according to a third aspect of the present invention is the liquid epoxy resin composition according to the first or second aspect, wherein the epoxy resin has a viscosity at 25 ° C. of 2,000 centipoise or less. An epoxy resin containing the resin in an amount of 50% by weight or more based on the total amount of the epoxy resin.

A liquid epoxy resin composition according to a fourth aspect of the present invention is the liquid epoxy resin composition according to any one of the first to third aspects, wherein the curing accelerator is a phosphorus compound. And

A liquid epoxy resin composition according to a fifth aspect of the present invention is the liquid epoxy resin composition according to the fourth aspect, wherein the curing accelerator is a phosphorus compound supported on a thermoplastic resin. .

Hereinafter, the present invention will be described in detail. An epoxy resin is used as a matrix resin constituting the liquid epoxy resin composition of the present invention. The epoxy resin may be liquid at room temperature, and may be a mixture of a liquid epoxy resin and a solid epoxy resin. This epoxy resin is an epoxy resin having two or more glycidyl groups in one molecule, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, halogenated epoxy resin, glycidyl ester type Examples include an epoxy resin, an alicyclic epoxy resin, and a biphenyl type epoxy resin, but are not limited thereto. Among these epoxy resins, a bisphenol F type epoxy resin obtained by molecular distillation and having a viscosity at 25 ° C. of 2000 centipoise or less is preferable, and the content of the bisphenol F type epoxy resin is 50% by weight or more based on the total amount of the epoxy resin. It is desirable that That is, the content ratio is 5
If the amount is less than 0% by weight, the viscosity of the liquid epoxy resin composition tends to increase, and the handleability tends to deteriorate.

It is essential that the curing agent used in the liquid epoxy resin composition of the present invention contains an allylated bisphenol compound and a compound having three or more phenolic hydroxyl groups in the molecule. That is, by containing an allylated bisphenol compound and a compound having three or more phenolic hydroxyl groups in the molecule, the liquid epoxy resin composition has a low viscosity and physical properties are improved. Various compounds can be used as the above-mentioned allylated bisphenol compound, but it is preferable to contain an allylated bisphenol represented by the following formula or the following formula from the viewpoint of ease of synthesis and low viscosity. The following formula,
Can be synthesized from non-allylated bisphenol. Unallylated bisphenols are generally high melting solids, and, like phenolic novolak resins, when used as a curing agent, it is difficult to impart good fluidity to the epoxy resin composition, By allylation,
The compound is a liquid compound at room temperature or a compound whose melting point is significantly reduced even in a solid state. Therefore, by using an allylated bisphenol as a curing agent, it becomes possible to obtain an epoxy resin composition containing a phenolic compound and being liquid at room temperature. However, when only the allylated bisphenol is used as a curing agent, there is a problem that the composition does not cure even when heated, so in the present invention, a compound having three or more phenolic hydroxyl groups in the molecule is used in combination. I have.

[0013]

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[0014]

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As the compound having three or more phenolic hydroxyl groups in the above molecule, various compounds can be used, and pyrogallol is preferred because the cured product has a high crosslinking density and a low viscosity. It is preferable from the point of view. The curing agent used in the present invention, in addition to the above curing agent,
Other curing agents may be used in combination as long as the properties are not impaired.

As the curing accelerator used in the liquid epoxy resin composition of the present invention, for example, phosphorus-based, tertiary amine-based,
Examples thereof include imidazoles and metal salts. Among these curing accelerators, phosphorus compounds such as triphenylphosphine are particularly preferred from the viewpoint of low moisture absorption of the cured product. In addition, when the curing accelerator is a phosphorus compound supported on a thermoplastic resin, the pot life of the liquid epoxy resin composition becomes longer, which is more preferable. The term “supported by a thermoplastic resin” as used herein means, for example, a state in which the thermoplastic resin and the phosphorus-based compound are mixed by various treatments such as adsorption treatment to the thermoplastic resin and microencapsulation by the thermoplastic resin. Is pointing to.

Examples of the filler used in the liquid epoxy resin composition of the present invention include crystalline silica, alumina, calcium carbonate, zinc oxide and the like. If necessary, a filler surface-treated with a coupling agent may be used. Can also.

Further, in the present invention, a flame retardant, a pigment, a dye, a release agent and the like can be added as required.

[0019]

In the present invention, the use of an allylated bisphenol compound as a curing agent and a compound having three or more phenolic hydroxyl groups in the molecule reduces the viscosity of the liquid epoxy resin composition and reduces the viscosity of the liquid epoxy resin composition. It acts to increase the reliability of the device.

[0020]

The present invention will be described below based on examples and comparative examples.

Examples 1 to 5 and Comparative Examples 1 and 2 The following two types of epoxy resins were blended in the proportions shown in Tables 1 and 2 and used. (1) Epoxy resin YD8125 --- epoxy equivalent 1
Bisphenol A type epoxy resin of molecular distillation type having a viscosity of 40 poise at 75 and 25 ° C. [Toto Kasei Co., Ltd.
YD8125] (2) Epoxy resin YDF8170 --- Bisphenol F-type epoxy resin with an epoxy equivalent of 160 and a viscosity of 20 poise at 25 ° C [Product number YDF8 manufactured by Toto Kasei Co., Ltd.
170]

As the curing agent, the following three types of curing agents were used in the proportions shown in Tables 1 and 2. (1) Curing agent PF0122--Part number PF012 (phenolic hydroxyl group equivalent: 154) manufactured by Mitsui Toatsu Chemicals, Inc., which is allylated bisphenol A represented by the above formula (2) Curing agent T0118 --- 2,2 ', 4,4'-tetrahydroxybenzophenone having a phenolic hydroxyl equivalent of 61.5 [manufactured by Toto Kasei Co., Ltd., product number T0
118]

[0023]

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(3) Hardener Pyrogallol--a reagent manufactured by Wako Pure Chemical Industries, Ltd., phenolic hydroxyl equivalent 42

As the hardening accelerator, the following three hardening accelerators were used in the proportions shown in Tables 1 and 2. (1) Curing accelerator SA102 ---- 1,8 Diaza-bicyclo- (5,4,0) undecene-7 [DBU] octylate [manufactured by San Avro Co., Ltd., product number SA102] (2) Curing accelerator TPP --- Triphenylphosphine, a reagent manufactured by Wako Pure Chemical Industries, Ltd. (3) Curing accelerator MCE-Acrylic resin which is a thermoplastic resin carries triphenylphosphine which is a curing accelerator. MCE manufactured by Nippon Kayaku Co., Ltd.
(With triphenylphosphine content of 5% by weight)

As the filler, crushed fused silica manufactured by Tatsumori Co., Ltd., trade name RD-8 was blended and used in the ratios shown in Tables 1 and 2.

Each raw material was blended based on the blending amounts (parts by weight) shown in Tables 1 and 2, and uniformly mixed with a homodispers to obtain a liquid epoxy resin composition.

Using the obtained liquid epoxy resin composition, a silicon chip having a circuit formed thereon, which is mounted on a test board, is sealed, and then heated at 120 ° C. for 1 hour.
It was cured by heating at 160 ° C. for 3 hours. Various properties of the liquid epoxy resin composition and the cured product thus obtained were measured, and the results are shown in Tables 1 and 2.

The measurement of various performances was performed as follows. [1] Viscosity The viscosity of the obtained liquid epoxy resin composition at 25 ° C. is represented by B
It was measured using a viscometer (initial viscosity).

[2] Pot life The viscosity of the obtained liquid epoxy resin composition at 25 ° C. after storage at 5 ° C. for 1 month was measured using a B-type viscometer, and the viscosity after storage for 1 month. Divided by the above initial viscosity was used.

[3] PCT reliability test The test board obtained by sealing and heating using the liquid epoxy resin composition was treated under the PCT conditions of 121 ° C., 2 atm, and 100% relative humidity. , And the time until the occurrence of a circuit failure was evaluated.

[4] TC reliability test The above test board obtained by sealing and heating using a liquid epoxy resin composition was subjected to a gas phase at -50 ° C for 30 minutes.
The process was performed with a temperature cycle of 5 minutes at room temperature and 30 minutes at 125 ° C. as one cycle, and evaluated by the number of cycles until a circuit failure occurred.

[5] Moisture Absorption Rate The liquid epoxy resin composition was formed into a disk having a diameter of 50 mm and a thickness of 3 mm, and the disk was heated at 120 ° C. for 1 hour, and further heated at 160 ° C. for 3 hours to obtain a test piece. The test piece was treated under PCT conditions of 121 ° C., 2 atm, and 100% relative humidity for 500 hours, and the rate of weight increase after the treatment was determined as the moisture absorption rate.

[0034]

[Table 1]

[0035]

[Table 2]

From the results of Tables 1 and 2, it was confirmed that Examples of the present invention were superior to Comparative Example 1 in terms of viscosity, PCT reliability, TC reliability, and moisture absorption. In addition,
In Comparative Example 2, the curing agent was only the allylated bisphenol compound, and thus did not cure even when heated.

[0037]

The liquid epoxy resin composition according to the first to fifth aspects of the present invention is configured as described above, so that it has low viscosity and good handleability, and forms a resin sealing layer by spot sealing. By using the liquid epoxy resin composition of the invention according to claims 1 to 5, it is possible to obtain a highly reliable cured product excellent in moisture resistance, heat resistance, electric characteristics and the like. Become.

The liquid epoxy resin composition of the invention according to the fifth aspect is an epoxy resin composition having an excellent pot life in addition to the above effects.

Continuation of front page (56) References JP-A-8-198938 (JP, A) JP-A-8-85719 (JP, A) JP-A-8-67805 (JP, A) JP-A-8-12745 (JP) JP-A-6-268106 (JP, A) JP-A-6-145304 (JP, A) JP-A-6-100664 (JP, A) JP-A-6-128360 (JP, A) 63-225616 (JP, A) JP-A-62-297713 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 59/40 C08G 59/62 C08L 63/00-63 / Ten

Claims (5)

(57) [Claims] 1. An epoxy resin composition containing two or more glycidyl groups in a molecule, a curing agent, a curing accelerator, and a filler, the epoxy resin composition being liquid at room temperature, wherein the curing agent is allylated. Bisphenol compound and 3 in the molecule
A liquid epoxy resin composition comprising a compound having at least two phenolic hydroxyl groups. 2. The liquid epoxy resin composition according to claim 1, wherein the compound having three or more phenolic hydroxyl groups in the molecule is pyrogallol. 3. The epoxy resin according to claim 1, wherein the epoxy resin contains at least 50% by weight of a bisphenol F type epoxy resin having a viscosity at 25 ° C. of 2,000 centipoise or less based on the total amount of the epoxy resin. The liquid epoxy resin composition according to claim 2. 4. The liquid epoxy resin composition according to claim 1, wherein the curing accelerator is a phosphorus compound. 5. The liquid epoxy resin composition according to claim 4, wherein the curing accelerator is a phosphorus compound supported on a thermoplastic resin.