JPH0748500A - Epoxy resin composition for sealing of semiconductor - Google Patents

Abstract

PURPOSE:To obtain the composition excellent in moisture-resistance reliability and capable of readily forming a sealant for preventing corrosion of a wiring, etc., by adding a curing agent, a curing promoter and a specified ion scavenger to a resin having two or more epoxy groups in one molecule. CONSTITUTION:With (A) an epoxy resin having plural epoxy groups in one molecule, (B) a curing agent, (C) a curing promoter and (D) an ion scavenger are admixed. The used ion scavenger is a mixture composed of 75 to 85wt.% inorganic exchanger A prepared by coating 100 pts.wt. hydrotalcite-based compound of formula MgxAly(OH)2x+3y-2z(CO3)z.mH2O [(x), (y) and (z) are each a positive integer satisfying 0<y/x<=1 and 0<=z/y<1.5; (m) is a positive integer] or its calcined material with 0.1 to 0.8 pts.wt. silane coupling agent and 25-15wt.% antimonic acid. This ion scavenger can improve the epoxy resin composition in the electrical insulating properties and the moisture-resistance reliability while maintaining its satisfactory ion scavenging performance.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention can be widely used in the field of electronic materials, etc., because it can easily obtain a semiconductor encapsulant having high moisture resistance reliability and capable of preventing corrosion of wiring and the like. The present invention relates to an epoxy resin composition for semiconductor encapsulation.

[0002]

2. Description of the Related Art Most of semiconductors such as ICs, transistors and LSIs are sealed with an epoxy resin composition.
This epoxy resin composition, in addition to the epoxy resin as the main component, an epoxy resin curing agent, a curing accelerator, an inorganic filler,
Composed of flame retardants, pigments, silane coupling agents, etc. to prevent defects caused by ionic impurities in raw materials or moisture invading from the outside, as well as flame retardancy, high adhesion, crack resistance and high Various properties such as electrical properties such as volume resistivity are required.

On the other hand, with the recent high integration of semiconductors, IC
Due to the shrinking of the aluminum wiring width on the chip, aluminum corrosion started to occur early. This corrosion is mainly promoted by the water that has penetrated into the epoxy resin composition. Further, since the amount of heat generated is increased due to the reduction of the wiring width, a large amount of flame retardants such as antimony oxide, brominated epoxy resin, and inorganic hydroxide has been added to the epoxy resin composition. The corrosion of aluminum wiring is being further promoted by the combustor component.

In order to prevent the above-mentioned corrosion, it has been required for the epoxy resin composition to further improve the moisture resistance reliability. Already, in order to meet the demand for increasing the reliability of moisture resistance, it has been proposed to mix hydrotalcites, which are inorganic anion exchangers, with an epoxy resin in order to trap problematic impurity ions, particularly halogen ions. (JP-A-63-252451, JP-A-64-
64243 and JP-A-60-40124).

The epoxy resin composition for semiconductor encapsulation proposed above has a high humidity resistance reliability which can prevent corrosion of the encapsulated wiring and the like. However, when the hydrotalcites are blended with the epoxy resin composition, the moisture resistance reliability is improved, while the hot water extraction water conductivity, which is a measure of the hot water stability of the epoxy resin composition, increases. However, there is a problem that the electrical characteristics of the epoxy resin composition are deteriorated.

When the hydrotalcites are mixed with the epoxy resin, the hydrotalcites are usually subjected to a silane coupling treatment for the purpose of improving the adhesion with the epoxy resin, the dispersibility in the resin, and the stability. Proposals have been made repeatedly. The silane coupling treatment is achieved by condensing the silanol groups of the silane coupling agent with the hydroxyl groups in hydrotalcites. However, since the hydroxyl group has a role of a functional group for trapping ions, the silane coupling treatment reduces the ion trapping ability of hydrotalcites.
Therefore, when the ion trapping material is used for the purpose of improving the moisture resistance reliability, it is necessary to carefully control the silane coupling treatment conditions.

Further, it has been proposed to add antimonic acid together with hydrotalcites into an epoxy resin for the purpose of capturing impurities of anions and cations (JP-A-63-252451). Since antimonic acid is both an inorganic ion exchanger and a solid electrolyte, there is a problem that the volume resistivity of the epoxy resin composition decreases as the added amount increases because of its high conductivity. Further, since antimonic acid is a solid acid, there is a problem that bases such as amine and phosphine, which are curing accelerators for epoxy resins, are made inactive, and as a result, curing of epoxy resins is inhibited.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an epoxy resin composition which has high moisture resistance reliability, does not impair the curability of the epoxy resin, and does not impair the electrical insulation characteristics. is there.

[0009]

Means for Solving the Problems The inventors of the present invention have proposed a method for enhancing reliability of a semiconductor by incorporating an ion-trapping material into a composition for semiconductor encapsulating material to trap ionic impurities. By treating the talcite-based compound or its calcinable product with a specific amount of a silane coupling agent, and by containing antimonic acid in a specific ratio with respect to the hydrotalcite-based compound or its calcined product,
The inventors have found that the electrical characteristics (electrical insulation) and moisture resistance reliability of the epoxy resin composition can be improved while maintaining the ion trapping ability of the ion trapping material compounded in the encapsulant composition, thus completing the present invention. Came to do. That is, the present invention relates to an epoxy resin composition for semiconductor encapsulation, which comprises an epoxy resin having two or more epoxy groups in one molecule, a curing agent and a curing accelerator, and is a hydrotalcite-based compound represented by the following general formula. 75 to 85% by weight of an inorganic ion exchanger (A) and 25 to 15% by weight of a compound or a calcined product thereof, coated with 0.1 to 0.8 parts by weight of a silane coupling agent per 100 parts by weight thereof. % Of an ion scavenger is further contained in the epoxy resin composition for semiconductor encapsulation. _{Mg x Al y (OH) 2x} + 3y-2z (CO 3) z · mH 2 O [x, y and z, 0 <(y / x) ≦ 1 and 0 ≦ (z /
y) is a positive number satisfying <1.5, and m is a positive integer. The composition of the present invention essentially requires an epoxy resin having two or more epoxy groups in one molecule as described above, a curing agent, a curing accelerator and a specific ion scavenger, and optionally a flame retardant, It contains a pigment, a release agent and other additives.

Epoxy Resin The epoxy resin of the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule and is curable. Phenol / novolak type epoxy resin, bisphenol A type Any of those used as molding materials such as epoxy resin and alicyclic epoxy resin can be used.
Further, in order to enhance the moisture resistance of the composition of the present invention, it is desirable to use an epoxy resin having a chloride ion content of 10 ppm or less and a hydrolyzable chlorine content of 1000 ppm or less.

Curing Agent Any curing agent known as a curing agent for epoxy resin compositions can be used as the curing agent in the present invention, and preferred specific examples include acid anhydrides, amine curing agents and novolac curing agents. There are agents, etc.

○ Curing Accelerator As the curing accelerator in the present invention, any of those known as curing accelerators for epoxy resin compositions can be used. Preferred specific examples are amine-based, phosphorus-based, and imidazole-based curing accelerators. There are accelerators, etc.

Hydrotalcite-Based Compounds The hydrotalcite-based compounds in the present invention are compounds represented by the following general formula and their fired products. _{Mg x Al y (OH) 2x} + 3y-2z (CO 3) z · mH 2 O [x, y and z, 0 <(y / x) ≦ 1 and 0 ≦ (z /
y) is a positive number satisfying <1.5, and m is a positive integer. The hydrotalcite-based compound is a known compound whose production method is already known. In the present invention, the calcined product can be used in the same manner as the above hydrotalcite-based compound. A preferable firing temperature is 400 to
The temperature is 600 ° C., more preferably 450 to 550 ° C., and the preferable firing time is 2 to 15 hours. The hydrotalcite-based compounds in the present invention have an average particle size of 10 μm in order to facilitate dispersion in the epoxy resin.
The following are preferred.

Silane Coupling Treatment The silane coupling treatment in the present invention may be a method known as a silane coupling treatment method for inorganic powders, and preferable specific examples include the following method. (1) A method of spraying or vaporizing and spraying an aqueous solution of a silane coupling agent while stirring the dried inorganic powder. (2) A method in which the dried inorganic powder is dispersed again in water to form a slurry, and the silane coupling agent aqueous solution is added to the slurry while stirring to carry out treatment. (3) A method of vaporizing and spraying an aqueous solution of a silane coupling agent in a spray on the inorganic powder heated to a high temperature after completion of drying. In the present invention, the method (2) is desirable as a method for uniformly coating with a silane coupling agent and having high treatment efficiency. That is, in the methods (1) and (3), it is necessary that the inorganic powder is well dispersed in order to improve the uniform treatment and the treatment efficiency, but the amount of the silane coupling agent applied is large during the treatment. Or it may be spread unevenly. This is because in this case, the ion exchange capacity of the hydrotalcite-based compounds subjected to the silane coupling treatment may be significantly reduced.

The silane coupling agent which can be used in the present invention is not particularly limited in its type, and it is not limited to vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-mercaptopropyltrimethoxysilane and γ-methacryl silane. Various compounds such as roxypropyltrimethoxysilane can be used. Preferred silane coupling agents in the present invention are those known for epoxy resins, specifically, γ-glycidoxypropyltrimethoxysilane and N-β (aminoethyl) γ-aminopropyltrimethoxysilane. Silane, N-β
(Aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane and γ
-Aminopropyltotriethoxysilane and the like.

Coating amount with silane coupling agent The coating amount with the silane coupling agent must be determined so as not to reduce the ion exchange capacity of the hydrotalcite compounds. It is necessary to set the ratio to 0.1 to 0.8 part per 100 parts by weight of the site compound (hereinafter simply referred to as "part"). If the coating amount with the silane coupling agent is too small, the electrical properties such as electrical insulation of the epoxy resin composition are impaired, and conversely, if the coating amount is too large, the ion exchange capacity of the hydrotalcite-based compounds decreases. In addition, since the hydrotalcite-based compound aggregates, the dispersion in the epoxy resin may be impaired.

An example of a preferred silane coupling treatment method is as follows. A predetermined amount of hydrotalcite-based compound is dispersed in water and stirred. A desirable slurry concentration is 10 to 30% by weight. If it is more than this, the slurry viscosity increases, so the stirring efficiency decreases, it becomes difficult to coat the silane coupling agent uniformly, and conversely,
If the slurry concentration is low, uniform treatment is possible, but work efficiency may decrease. Then, select the appropriate concentration (usually
An aqueous solution of a silane coupling agent (about 1% by weight) is prepared, added to a slurry in which hydrotalcite-based compounds are dispersed, stirred for 24 hours, filtered, washed with water, and dried to obtain a silane-coupling inorganic material. An ion exchanger (A) can be obtained.

Antimonic Acid (B) Antimonic acid in the present invention is a compound represented by the following general formula, and is a known compound for which various production methods are known. Sb2 O5.nH2 O (n is a positive integer.) In the present invention, it is desirable to use crystalline antimonic acid in order to make the epoxy resin composition exhibit high moisture resistance.

Since the hydrotalcite-based compounds are basic substances which cause the PH value of hot water to become 9 or more when left in hot water, when they are blended alone into the epoxy resin, Has a problem of corroding aluminum wiring and the like. This problem can be solved by using antimonic acid, which is a solid acid, in a specific proportion.

In addition, when antimonic acid is used in combination with hydrotalcite-based compounds, it also has the effect of synergistically increasing the anion-capturing ability of hydrotalcite-based compounds. The blending ratio with acid becomes an important control factor. Therefore, the compounding ratio of the inorganic ion exchanger (A) and the antimonic acid (B) in the ion scavenger of the present invention is 75% for the inorganic ion exchanger (A) based on the total weight of (A) and (B). ~ 85% by weight (hereinafter simply referred to as%)
It is necessary to control the antimonic acid (B) to 25 to 15%, and it is preferable to control so that (A) is 78 to 82% and (B) is 22 to 18%. is there. When (B) is more than 25%, antimonic acid is a solid electrolyte and the volume resistivity of itself is very low. There is a problem of damage, while (B)
If less than 15%, the inorganic ion exchanger (A) is too basic, so that corrosion of the wiring cannot be suppressed.

Desired Components The epoxy resin composition of the present invention may further contain inorganic fillers, flame retardants, coupling agents for inorganic fillers, colorants, release agents, etc., as desired components. Will be completed.
All of these desired components are known as components to be added to the molding epoxy resin.

Preferred specific examples of the inorganic filler include crystalline silica powder, quartz glass powder, fused silica powder, alumina powder and talc. Among them, crystalline silica powder, quartz glass powder and fused silica powder are inexpensive. preferable. Examples of flame retardants include antimony oxide and halogenated epoxy resins, examples of coupling agents include silane-based and titanium-based agents, and examples of release agents include aliphatic paraffins and higher aliphatic compounds. There are various waxes such as alcohol.

Mixing ratio of ion scavenger The preferable mixing ratio of the ion scavenger comprising the antimonic acid (B) and the inorganic ion exchanger (A) is the composition 1 of the present invention.
0.1 to 10 parts per 00 parts, more preferably 1
~ 5 parts. If it is less than 0.1 part, the effect of improving the moisture resistance reliability is small, while if it exceeds 10 parts, the effect is no longer improved, and conversely the cost is increased, which is not preferable.

Preparation Method of Composition The epoxy resin composition of the present invention can be easily obtained by mixing the above-mentioned raw materials by a known method. For example, the above-mentioned respective raw materials are appropriately blended, and this blend is prepared. It is obtained by kneading in a kneading machine in a heated state to obtain a semi-cured resin composition, cooling this to room temperature, pulverizing it by a known means, and tableting if necessary. The mixing ratio of the ion scavenger in the present invention is preferably such that the inorganic ion exchanger (A) and the antimonic acid (B) are preliminarily uniformly mixed rather than separately. By doing so, the effect of using these components in combination can be remarkably exhibited.

[0025]

[Examples and Comparative Examples]

Reference Example ○ Preparation of Inorganic Ion Exchanger (A) Silane Coupling Agent (γ-Glycidoxypropyltrimethoxysilane, Product Name A-1 manufactured by Nippon Unicar Co., Ltd.)
87) 1% by weight of an aqueous solution was prepared, and then this was added to 30 g of a hydrotalcite-based compound calcined product (M
g _0.7 Al _0.3 O _1.15 ) was added to 100 ml of the slurry in an amount shown in Table 1 below. Then 24
After stirring at room temperature for hours, it was filtered, washed with water, and dried at 110 ° C. to obtain an inorganic ion exchanger (A) composed of silane coupling-treated hydrotalcite-based compounds.

[0026]

[Table 1] Note) The addition ratio is a value calculated by the formula of “(addition amount of aqueous solution of silane coupling agent / 30)”.

Evaluation of Ion Scavenger An evaluation method is shown below by using an ion scavenger powder in which the inorganic ion exchanger (A) obtained as described above is mixed with a predetermined ratio of antimonic acid (B). Various measurements were performed. The following Table 2 shows the mixing ratio of the inorganic ion exchanger (A) and antimonic acid (B).

Hot water extraction test: 1.0 g powder and 1 pure water
Add 00 ml to a 250 ml polyethylene bottle and
After standing at 5 ° C. for 15 hours, the mixture was filtered, and the electrical conductivity and PH value of the filtrate were measured.

Ion exchange capacity: 50 g per 1.0 g of powder
l 0.1N-NaCl was added, and the mixture was stirred at 40 ° C. for 15 hours and then filtered, the Cl ion concentration in the filtrate was determined by silver nitrate titration, and the ion exchange capacity was calculated from the decrease amount.

Volume resistivity: Powder is molded into pellets (13 mmφ × 2 mm ^t ) by a tablet molding machine (400 kg
/ Cm ² for 1 minute), a silver paste was applied, electrodes were prepared, and then measured with a high insulation resistance measuring device. The results evaluated as described above are shown in Tables 2 and 3 below. However, the meanings of the abbreviations shown in Tables 2 and 3 and the units of the evaluation values are as follows.・ (A): Inorganic ion exchanger (A) obtained in the reference example (the number indicating the type indicates the conditions of the silane coupling treatment in Table 1) ・ (B): Antimonic acid (B) ・ Electrical conductivity Unit of degree: μS / cm ・ Unit of ion exchange capacity: meq / g

[0031]

[Table 2]

[0032]

[Table 3]

From the results of Examples 1 to 5, when the silane coupling-treated inorganic ion exchanger (A) and antimonic acid (B) were blended at a specific ratio as in the present invention, Since it does not release impurities in hot water and the neutralizing property of the liquid is retained, it does not impair the electrical properties such as the electrical insulation of the sealed product, and exerts the ion trapping ability.
It suggests that a sealed product with high humidity resistance can be obtained.

On the other hand, Comparative Examples 1 to 11 have the following problems. In Comparative Examples 1 to 5, the electrical conductivity is high in the hot water extraction test. This suggests that the cured product of the resin containing these powders has poor electrical properties, particularly electrical insulation. Comparative Examples 6, 7, 9 and 10 showed P in the hot water extraction test.
All H values are 9 or more. This suggests that if the semiconductor is encapsulated with a resin containing these powders, the wiring is easily broken. Comparative Examples 8 and 11
The volume resistivity is small because the blending ratio of antimonic acid is too large. This suggests that the cured product of the resin containing these powders has poor electrical properties, particularly electrical insulation.

Preparation of Epoxy Resin Composition for Semiconductor Encapsulation Each component was blended with the following composition, and the mixture was kneaded with a hot roll at 80 ° C. to 90 ° C. for 3 to 5 minutes, then cooled and pulverized. A powdery epoxy resin composition was obtained.

[0036]

[Table 4] ─────────────────────────────────── Cresol Novolac type epoxy resin (epoxy equivalent 235) 80 Part Brominated phenol novolac type epoxy resin (epoxy equivalent 275) 20 parts Phenol novolac resin (molecular weight 700-1000) 50 parts Triphenylphosphine 2 parts Carbana wax 1 part Carbon black 1 part Fused silica 370 parts Ions obtained in the examples Powder of scavenger 0 or 5 parts

○ Reliability Evaluation Method Among the compositions obtained as described above, using a sample of 100 mesh pass, molding conditions of 170 ° C. and setting of 3 minutes, moisture resistance reliability in which aluminum wiring is connected The evaluation element is sealed, and the sealed element is heated to 125 ° C.
The pressure cooker test was carried out and the time at which wire breakage occurred was measured. This test was performed with 50 samples and the average value was obtained. The test results are shown in Table 5 below.

[0038]

[Table 5]

On the other hand, in the composition shown in Table 4, an epoxy resin composition for semiconductor encapsulation was prepared with a composition containing no ion trapping agent powder obtained in Example, and the semiconductor was encapsulated using this resin. In some cases, a break occurred at 150 hours. On the other hand, as shown in Table 5 above, when the composition of the present invention was used for sealing, disconnection did not occur for 500 hours or more.

Method for Evaluating Curability of Epoxy Resin Composition for Semiconductor Encapsulation A composition prepared by using the ion scavenger of Example 5 or Comparative Example 3 in the composition shown in Table 4 was prepared at 80 ° C to 90 ° C. The mixture was kneaded for 3 to 5 minutes with a hot roll heated to 1, then cooled and pulverized to obtain a powdery epoxy resin composition. A curability meter was used to evaluate the curability of a 100 mesh pass sample of the composition obtained. The measurement conditions at this time are as follows. Heating temperature: 175 ° C. Curing start time: Time from the start of heating until the torque starts to rise Curing degree: Torque width after 5 minutes from the start of curing The results of evaluation of curability as described above are shown in Table 6 below. It was

[0041]

[Table 6]

As can be seen from Table 6 above, the curability of the composition of the present invention is not impaired by the silane coupling treatment of the hydrotalcite compound or its fired product.

[0043]

The epoxy resin composition for semiconductor encapsulation of the present invention is excellent in the anticorrosion effect of encapsulated wiring without impairing the electrical properties of the cured resin and the curability of the epoxy resin composition, Extremely high humidity resistance reliability.

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Claims (1)

[Claims] 1. A hydrotalcite-based compound represented by the following general formula in an epoxy resin composition for semiconductor encapsulation comprising an epoxy resin having two or more epoxy groups in one molecule, a curing agent and a curing accelerator. Or the burned product 1
Inorganic ion exchanger (A) 75 to 85 coated with 0.1 to 0.8 part by weight of silane coupling agent per 00 parts by weight
An epoxy resin composition for semiconductor encapsulation, further comprising an ion scavenger composed of 25% by weight and 25 to 15% by weight of antimonic acid (B). _{Mg x Al y (OH) 2x} + 3y-2z (CO 3) z · mH 2 O [x, y and z, 0 <(y / x) ≦ 1 and 0 ≦ (z /
y) is a positive number satisfying <1.5, and m is a positive integer. ]