JPS62195016A - One-pack type epoxy resin composition - Google Patents

Abstract

PURPOSE:The titled composition having improved strength, heat resistance, water-vapor resistance, impact resistance, etc., high curing rate and a long pot life, obtained by blending an epoxy resin with a specific amount of a specified imidazole compound as a curing agent and a specific amount of an inorganic filler having specific particle diameter as a filler. CONSTITUTION:(A) 100pts.wt. epoxy resin (preferably having <=10ppm Na<+>, <=10ppm Cl<-> and <=0.01wt% hydrolysis chlorine is blended with (B) 2-8pts.wt. imidazole compound shown by formula I (m is 1-14; n is 0-2; R<1>-R<3> are H, alkyl or phenyl) and/or (ii) formula II (R<4> is H, methyl or hydroxymethyl; R<5> is alkyl or phenyl) as a curing agent and (C) 100-350pts.wt. inorganic filler (preferably silica or aluminum hydroxide) having 5-60mum average particle diameter as a filler to give the aimed composition.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a resin encapsulation material for protecting semiconductor chips and the like from external stress such as temperature, humidity, impact, etc. The present invention relates to a one-component epoxy resin composition used for directly bonding semiconductor elements and encapsulating chip-on-boards and hybrid ICs.

Conventional technology In recent years, the encapsulation of semiconductor devices has become more and more popular due to the small-volume, high-mix production of dedicated ICs, and the miniaturization and thinning of entire circuits. Methods to do this have been implemented in various fields such as watches and electronic thermometers. In the encapsulation of hybrid ICs and chip-on-boards, regarding the curing of the encapsulation material,
A method of melting and heating curing a pellet-shaped sealing material obtained by cold-opening epoxy molding material, and thermosetting a two-component epoxy potting sealing material or a molded epoxy potting material using a curing agent such as an acid anhydride. There are known methods to do this. However, the method of using pellet-shaped encapsulation material has the drawbacks of increased costs at the pellet forming stage, and poor workability because the operation of accurately applying electricity to the pellet on the semiconductor chip cannot be incorporated into the automated process. be. In this respect, since the liquid material can be accurately measured in the required amount by dispensing a fixed amount using a dispenser, it is advantageous that it can be incorporated into automation. However, in general, it is essential to contain 50% by weight or more of a filler in order to ensure the moisture resistance reliability and low coefficient of linear expansion required for a sealing material for semiconductor devices, but if the filler is included that much, the viscosity is generally quite high. Becomes a material. Therefore, when using a two-component material, it is very difficult to remove bubbles during the mixing process before use. If the viscosity is lowered to improve this point, the sealing material becomes extremely low in viscosity at the high temperature during curing, resulting in poor shape retention and other problems such as settling of the filler.

Based on the above, it can be said that a high viscosity one-component type sealing material is suitable in terms of quantity. Furthermore, when sealing a hybrid IC or chip-on-board, a semiconductor chip or the like is placed directly on a substrate and sealed, so higher interfacial adhesion is required than in the case of transfer sealing. In addition, there is an increasing demand for flame retardancy for electronic components, and there is a tendency for not only substrates on which semiconductors are mounted, but also semiconductor sealing materials to be required to have flame retardancy.

Problems to be Solved by the Invention On the other hand, - Various deep epoxy resin compositions are known, but they have a fast curing speed and do not have the heat resistance, strength, and moisture resistance reliability necessary for semiconductor encapsulation materials. To date, no material with excellent properties such as low expansion properties and impact resistance has been developed.

The present invention was developed in view of these circumstances, and it has the performance necessary for sealing semiconductor devices, has a fast curing speed, has good storage stability, and has a low viscosity for sealing with a dispenser. The purpose of the present invention is to provide the following one-component epoxy resin composition that can perform the following steps.

That is, the present invention is a composition containing an epoxy resin, a curing agent, and a filler, comprising: (a) epoxy resin: 100 parts by weight (b)
As a curing agent, at least one imidazole compound selected from the compounds represented by the following general formula (A) or (B): 2 to 8 parts by weight (in the formula, m is 1 to 14,
n l"t An integer of O~2, R1, n, 2, and R3 represent a hydrogen atom, an alkyl group, or a phenyl group.) (In the formula, t represents a hydrogen atom, a methyl group, or a hydroxymethyl group, and R5 represents an alkyl group. or phenyl group.) 6-(c) An inorganic filler with an average particle size in the range of 5 to 60 pm as a filler. A liquid containing 100 to 350 parts by weight. type epoxy resin composition.

(Epoxy Resin) The type of epoxy resin is not particularly limited as long as it is a liquid epoxy resin, but bisphenol A epoxy resins and/or bisphenol F epoxy resins having an epoxy equivalent of 200 or less are preferably used. Even solid epoxy resins such as (cresol) novolak type epoxy resins can be used in combination with liquid epoxy resins to form a dripping system in which the entire resin is in a liquid state. The epoxy resin should preferably be of high purity and low content of ionic impurities such as sodium ions and chloride ions from the viewpoint of electrical performance. Particularly preferred are those in which the content of chlorine is 0.01% by weight or less, and the total chlorine content is 0.1% by weight or less.

(Curing agent) The curing agent is one or more imidazole compounds selected from the compounds represented by the general formulas (A and (Bl).

Examples of the imidazole compound represented by the general formula (A) include 2,4-diamino-6(gumethylimidazolyl-(1
Adducts of ethyl-8-) riazine and isocyanuric acid (containing water of crystallization), and imidazole compounds represented by the general formula (13+) include 2-phenyl-4-methyl-5
-Hydroxymethylimidazole, and 2-phenyl-
Examples include 4,5-dihydroxymethylimidazole.

The amount of these curing agents is 2 to 100 parts by weight of epoxy resin.
8 parts by weight are used. If the amount of the curing agent is less than 2 parts by weight, the curability will be poor, and if the amount of the curing agent is more than 8 parts by weight, the storage stability will decrease, the viscosity of the composition will increase, and the moisture resistance will also decrease, which is undesirable. .

It is preferable to use the minimum necessary amount of the curing agent, and preferably about 3 to 5 parts by weight per 100 parts by weight of the epoxy resin. The epoxy resin composition of the present invention can also be used in combination with the imidazole compound and various known curing agents. Preferred curing agents include dihydrazides derived from organic dibasic acids such as oxalic acid, malonic acid, succinic acid, acihinic acid, sebacic acid, dodecanedioic acid, hexadecanedioic acid, and isophthalic acid. When an organic dibasic acid hydrazide is used in combination, it is preferably used in an amount of about 1 to 3 moles per 100 moles of the epoxy resin.

(Filler) The inorganic filler used in the present invention has an average particle size of 5 to 60
pm range, and if the average particle size is smaller than 5pm, the viscosity of the system will be high and problems will occur in terms of workability.
If it is thicker than pm, sedimentation of particles is observed and it is not practical.

Further, from the viewpoint of the balance between particle size and sedimentation property, it is preferable that the particle size distribution of the filler is wide, and the proportion of the filler contained within the particle size of 20 to 100 pm is preferably 50 to 80 wt%.

The filler is 100 to 35 parts by weight per 100 parts by weight of epoxy resin.
0 parts by weight are used. If it is less than 100 parts by weight, the linear expansion coefficient, water absorption rate, etc. of the cured composition will be high, which is undesirable. If it is more than 350 parts by weight, the viscosity of the system will increase and workability will decrease, which is not practical.

Specific examples of inorganic fillers include pulverized or unpulverized fused silica, crystalline silica, aluminum hydroxide, alumina, zirconium oxide, zirconium silicate, antimony trioxide, glass particles, and calcium carbonate. Among them, those containing 30 parts by weight or more of fused silica having excellent filling properties, purity, etc. are preferred, and those containing 500 parts by weight or more are more preferred. Further, it is particularly preferable to use aluminum hydroxide, which has excellent filling properties and improves stickiness, tracking resistance, and flame retardancy, in combination with fused silica.

When using fused silica and aluminum hydroxide together, the amount of aluminum hydroxide is 5 parts by weight per 100 parts by weight of epoxy resin.
It is preferable to use ~50 parts by weight, and the ratio of the sum of silica and aluminum hydroxide in the filler to the inorganic filler is 80 parts by weight from the viewpoint of purity, moisture resistance, and fillability.
It is preferably at least % by weight. Further, as a flame retardant filler, antimony trioxide can be used in place of aluminum hydroxide within a range of 80% by weight of aluminum hydroxide.

Like the epoxy resin, the inorganic filler preferably has a low amount of ionic impurities, and the content of sodium ions and chlorine ions in the filler is 200 p1) rll, 10, respectively.
It is preferably less than ppm.

The filler used in the present invention may be surface-treated with a known coupling agent such as a silane coupling agent, if necessary.

Typical examples of the coupling agent used in the present invention include epoxysilane, vinylsilane borane compounds, alkoxy titanate compounds, and aminosilane aluminum chelate compounds.

Of these, γ-glycidoxypropyltrimethoxysilay
, l-(a,4-epoxycyclohexyl)ethyltrimethoxysilane, pinyltino-2-methoxysilane, vinyltri-2-methoxysilane, and phenyltrimethoxysilane are preferably used, but the fillability and epoxy resin γ-glycidoxyprobyltrimethoxysilane, which has excellent reactivity with β-
It is particularly preferred to use (3,4-epoxycyclohexyl)ethyltrimethoxysilane and phenyltrimethoxysilane, which has excellent resistance to dust. These coupling agents can be used alone or in combination of two or more, and the amount used is α1 to 4 parts by weight, preferably 0.5 parts by weight, based on 100 parts by weight of the filler.
It is in the range of 2 to 2 parts by weight.

If it is less than 0 or i parts by weight, the adhesion between the filler and the epoxy resin will be poor, resulting in a decrease in moisture resistance, and if it is less than 4 parts by weight, an excess of the coupling agent will accelerate the deterioration of the resin, resulting in a decrease in moisture resistance. .

(Additional Components) In addition to the epoxy resin, curing agent, and filler, various known additives can be added to the composition of the present invention as necessary. For example, various types of curing accelerators, flame retardants, flame retardant aids, various leveling agents, thixotropic agents, antisettling agents, dyes, pigments, antifoaming agents, rust preventives, corrosion inhibitors, adhesion agents, etc. I can list additives. When using a known halogen compound or phosphorus compound as a flame retardant, it is not preferable to use a compound that significantly increases the viscosity of the composition, a large content of ionic impurities, or a compound that reduces the curability of the curing agent. Preferred flame retardants include red phosphorus, brominated epoxy resins, and the like. Red phosphorus, usually used in combination with aluminum hydroxide to increase its effect, preferably contains phosphate ions of less than SO oppm, and 30 parts by weight per 100 parts by weight of epoxy resin. If more than that is used, the electrical properties of the cured product after absorbing moisture will deteriorate, which is undesirable.

(Formulation) The one-component epoxy resin composition of the present invention can be obtained, for example, by mixing the raw materials as described above and then kneading the mixture. Kneading is carried out using a niegu, roll, mixer, or the like. It is preferable to degas under reduced pressure during or after mixing.

The one-component epoxy resin composition of the present invention has excellent heat resistance, strength, moisture resistance reliability, low expansion, impact resistance, etc. required as a sealing material for semiconductor devices, has a fast curing speed, and has a short pot life. It is a one-component epoxy resin composition that can be sealed using a dispenser.

Experimental example Next, Examples and Comparative Examples will be described.

Example 1 Bisphenol A type epoxy resin (epoxy equivalent: 190
) 100 parts by weight, 2,4-diamino-6(2'-methyl-imidazole(
1:
) with an average particle size of 15 pm (from 20 pm to 100 pm) as a filler.
Premix by adding 200 parts by weight of fused silica (Fuselex RD-8, trade name of Ryumorisha) containing 60 wt4 in the range of m and 1 part by weight of γ-glycidoxypropyltrimethoxysilane as a coupling agent. After that, the mixture was kneaded with three rolls and degassed to prepare a one-component epoxy resin composition.

Viscosity of the composition (measured at 25°C with a B-type rotational viscometer), gelation time (measured as the time until fluidity disappears after collecting the sample on a hot plate kept at 130°C),
Pot life (days when the viscosity reaches twice the initial viscosity) Stored at 35℃
, are shown in Table 1VC.

Further, using this composition, a silicon element for moisture resistance evaluation was sealed with a dispenser and cured at 150° C. for 3 hours to obtain a sample for moisture resistance test. The moisture resistance test is PCT (Pressu
(re Cooker'l'est) Measured by the failure occurrence time under conditions of 121° C. and 2 atm. Table 1 shows the results.
Shown below.

Example 2 In Example 1, 2-phenyl-4 was used as the curing agent. A sample was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 Same as Example 1 except that 4 parts by weight of 2-phenyl-4-methyl-5-hydroxymethylimidazole and 1 part by weight of sebacic acid dihydrazide (manufactured by Nippon Hydrazine Co., Ltd.) were used as the curing agent in Example 2. Samples were prepared and evaluated. The results are shown in Table 1.

Example 4 In Example 2, using 5 parts by weight of the curing agent, 180 parts by weight of fused silica and 30 parts by weight of aluminum hydroxide (average particle size 650 pm) as fillers,
A sample was prepared and evaluated in the same manner as in Example 2, except that 15 parts by weight (20 pm) was added.

The results are shown in Table 1.

Comparative Example 1 A sample was prepared and evaluated in the same manner as in Example 1, except that 2-ethyl-4-methylimidazole (2E4MZ, manufactured by Shikoku Kasei Co., Ltd.) was used as the curing agent. The results are shown in Table 1.

Comparative Example 2 Example 1 except that 20 parts by weight of filler was used in Example 1.
Samples were prepared and evaluated in the same manner. Similarly, when sealing and curing with a dispenser, the viscosity was too low, so a frame had to be installed to maintain the shape.

The results are shown in Table 1.

Comparative Example 3 A sample was prepared in the same manner as in Example 1 except that 200 parts by weight of fused silica with an average particle size of 3 pm was used in Example 1, but the viscosity was high and sealing with a dispenser was difficult. The results are shown in Table 1.

(Margin below)

Claims (2)

[Claims] (1) A composition containing an epoxy resin, a curing agent, and a filler, (a) Epoxy resin: 100 parts by weight (b) As a curing agent, the following general formula (A) or (B) is used. At least one imidazole compound selected from the compounds shown.
...2 to 8 parts by weight ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (A) (In the formula, m is an integer from 1 to 14, n is an integer from 0 to 2, R^1,
R^2 and R^3 represent a hydrogen atom, an alkyl group or a phenyl group. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(B) (In the formula, R^4 represents a hydrogen atom, methyl group, or hydroxymethyl group, and R^5 represents an alkyl group or phenyl group.) (c) Filling A one-component epoxy resin composition containing as an agent an inorganic filler having an average particle size in the range of 5 to 60 pm in a proportion of 100 to 350 parts by weight. (2) The composition according to claim 1, wherein the inorganic filler contains silica and aluminum hydroxide, and the proportion of the sum of the two in the inorganic filler is 80% by weight or more.