KR20190052362A - Epoxy resin composition - Google Patents

Abstract

The present invention relates to an epoxy resin composition, capable of excellently exhibiting bending properties and reliability, which comprises an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler, wherein the epoxy resin includes a dimer acid modified epoxy resin having a modification rate of 5 to 15%.

Description

EPOXY RESIN COMPOSITION [0002]

The present invention relates to an epoxy resin composition for semiconductor encapsulation.

Semiconductor encapsulant is a material that encapsulates a semiconductor device and protects it from external impact and contaminants, and has a great influence on the productivity and reliability of a semiconductor.

Recently, portable digital devices with small and thin designs have become popular, so that thinning and miniaturization of a semiconductor package for increasing the mounting efficiency per unit volume of the semiconductor package is indispensably required. As the package becomes thin and thin, the thermal expansion coefficient (CTE) difference between the semiconductor chip, the lead frame and the epoxy resin composition constituting the package, the heat shrinkage and the curing shrinkage of the epoxy resin composition sealing the package, Warpage occurs. When a bending problem of the package occurs as described above, it is a basic requirement for securing reliability to lower the content of the inorganic filler having a low coefficient of thermal expansion (CTE) in order to increase the hardening shrinkage ratio of the epoxy resin composition. However, when the content of the inorganic filler is reduced in order to improve the bending property, the moisture absorption rate of the epoxy resin composition for semiconductor encapsulation becomes relatively high, which inevitably leads to deterioration of the reliability of the package. Therefore, in the case of a package having poor reliability, there is a limitation in lowering the content of the inorganic filler in order to improve the bending property.

The present invention provides an epoxy resin composition for semiconductor encapsulation which can exhibit excellent bending properties and reliability even when a high content of an inorganic filler is contained.

The present invention provides an epoxy resin composition comprising an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler, wherein the epoxy resin comprises a dimer acid-modified epoxy resin having a modifying ratio of 5-15%.

The present invention also provides a semiconductor device encapsulated using the above-described epoxy resin composition.

In the present invention, dimer acid-modified epoxy resin is used and its modifying ratio is controlled within a specific range, so that flexibility and shrinkage ratio can be improved as compared with a conventional semiconductor encapsulating composition using a non-modified epoxy resin, Excellent warpage characteristics, hygroscopicity and reliability can be secured at the same time without lowering the content of the filler. Accordingly, the epoxy resin composition for semiconductor encapsulation of the present invention can be usefully used in accordance with the trend of light weight shortening of semiconductor packages.

Hereinafter, the present invention will be described in detail. However, it should be understood that the present invention is not limited to the following embodiments, and various elements may be modified or selectively mixed according to need. Accordingly, it is to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

≪ Epoxy resin composition &

The epoxy resin composition according to the present invention comprises an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler, and the epoxy resin includes a dimer acid-modified epoxy resin. If necessary, it may further include at least one additive commonly used in the art such as a coupling agent, a colorant, a release agent, a modifier, a flame retardant, and a low-stressing agent.

Hereinafter, the composition of the epoxy resin composition will be specifically described.

Dimer acid  Modified epoxy resin

The epoxy resin composition of the present invention comprises a dimeric acid-modified epoxy resin. The dimeric acid-modified epoxy resin is formed by reacting an epoxy resin modified with a dimeric acid, that is, an epoxy resin with at least one carboxyl group in the dimeric acid structure. Here, the dimer acid refers to a dimer synthesized by using an unsaturated fatty acid as a monomer. The structure of the dimer acid in the present invention is not particularly limited, and any of ring-shaped and non-ring-shaped rings known in the art may be used.

In the present invention, the unsaturated fatty acid forming the dimeric acid may be any of those used in the art without limitation, and examples thereof include monovalent fatty acids, polyvalent fatty acids having a valence of 2 or more, or a mixture of two or more thereof.

Examples of usable monovalent fatty acids include benzoic acid, acrylic acid, methacrylic acid, soybean oil fatty acid, tall oil fatty acid, castor oil fatty acid, rice oil fatty acid, linseed oil fatty acid, coconut oil fatty acid, lauric acid, linoleic acid, ≪ / RTI > Examples of the dihydric or higher valent polyhydric aliphatic acids include phthalic anhydride, maleic anhydride, isophthalic acid, adipic acid, tetrahydrophthalic anhydride, terephthalic acid, azelaic acid, heptanoic acid, sebacic acid, fumaric acid, Nitric acid or dimeric acid. For example, a plant-derived oil containing an unsaturated fatty acid having 12 to 18 carbon atoms such as oleic acid or linoleic acid as a main component may be used.

The dimeric acid-modified epoxy resin may have the structure of the following formula (1), but is not particularly limited to this structure.

In this formula,

R is a divalent group derived from a dimer acid having 10 to 40 carbon atoms,

R ₁ , R ₂ and R ₃ are the same as or different from each other, and are each independently hydrogen or an alkyl group having 1-6 carbon atoms,

n is an integer of 0-5.

For example, the dimeric acid-modified epoxy resin represented by Formula 1 may be prepared by the following Reaction Scheme 1.

[Reaction Scheme 1]

Describing the above-mentioned Reaction Scheme 1 as an example, a dimeric acid-modified epoxy resin in which a dicyclopentadiene-type epoxy resin is modified with C25 dimeric acid (fatty acid) and a dimer acid is bonded at the end of the epoxy may be formed. Such a modified epoxy resin has a higher molecular weight due to a moiety derived from a dimer acid introduced in the molecule (for example, R in the formula (1)), and the crosslinking point distance between the epoxy resins increases, thereby improving the flexibility and shrinkage of the cured product.

The dimeric acid-modified epoxy resin can easily form a cured product imparting flexibility and flexibility to the cured product due to the structure of the dimeric acid-modified part when the cured product is formed by the curing reaction, It is possible to improve the adhesion between the object (e.g., a semiconductor element) and the sealing material (EMC), heat resistance, and moisture resistance. Further, by adding the dimeric acid-modified epoxy resin, the amount of the flexible component in the cured product increases, and even when a large amount of the inorganic filler is used in an amount of not less than 86% by weight, good dimensional change ratio and warpage property can be achieved.

The dimer acid modification ratio of the modified epoxy resin may be in the range of 5-15% with respect to the total epoxy solid content, and may be in the range of 5-13%, for example. If the dimer acid modification ratio is less than 5%, the effect of improving the desired shrinkage percentage may be insignificant. On the other hand, when the dimer acid modification ratio exceeds 15%, the curability is lowered, and it is difficult to solidify and crush the dimeric acid-modified epoxy resin after synthesis.

The melt viscosity at 150 캜 as measured using an ICI viscometer (Research Equip., TW 5NX) of the dimeric acid-modified epoxy resin may be 2 poise or less, for example, 0.5-1.5 poise. The softening point of the epoxy resin may be 80 占 폚 or lower, for example, 55-65 占 폚. Due to the low melt viscosity and the softening point, the content of the inorganic filler can be set to be higher than 80 wt%, for example, in the range of 85-91 wt%, and kneading can be easily performed.

The epoxy equivalent of the dimeric acid-modified epoxy resin is not particularly limited. For example, the epoxy equivalent (EEW) may be in the range of 200-500 g / eq, and in another example 300-400 g / eq. When the epoxy equivalence is within the aforementioned range, the flexibility is improved and the shrinkage rate can be improved.

 The dimeric acid-modified epoxy resin used in the present invention is not particularly limited to the epoxy type as long as the dimeric acid modification ratio within the above-mentioned range is satisfied.

As the epoxy component of the epoxy resin modified with the dimeric acid, various epoxy resins known in the art can be used. Examples of the epoxy resin include a dicyclopentadiene type epoxy resin, a bisphenol type epoxy resin, a biphenyl type epoxy resin, a glycidyl ester type epoxy resin, an ether ester type epoxy resin, a novolac epoxy type epoxy resin, A dimer acid-modified epoxy resin obtained by modifying an epoxy resin with a dimer acid such as an epoxy resin, an aromatic epoxy resin or a polyaromatic epoxy resin can be suitably used. For example, a biphenyl type epoxy resin modified with a dimer acid can be used.

In the present invention, as the epoxy resin, one type of epoxy resin may be used alone, or two or more kinds of epoxy resins may be used in combination. When two or more kinds of epoxy resins are used, different types of epoxy resins may be used in combination, or epoxy resins differing in dimer acid modification ratio may be used.

In the present invention, an epoxy resin modified with a dimer acid, which is a dimeric form of an unsaturated fatty acid, is mainly described. However, the present invention is not limited thereto and it is also within the scope of the present invention to use an epoxy resin modified with a common fatty acid known in the art .

In the epoxy resin composition according to the present invention, the content of the dimeric acid-modified epoxy resin may range from 3 to 10% by weight, for example, from 3 to 7% by weight based on the total weight of the epoxy resin composition. When the content of the dimeric acid-modified epoxy resin falls within the above range, the flexibility, curability, and warpage characteristics of the epoxy resin composition are satisfactory.

Non-denaturation  Epoxy resin

The epoxy resin composition of the present invention may contain, in addition to the aforementioned dimeric acid-modified epoxy resin, an epoxy resin commonly used in a semiconductor encapsulant such as a non-modified epoxy resin.

The epoxy resin that can be used is not particularly limited, and conventional epoxy resins known in the art can be used. Examples of the epoxy resin include a polymer or oligomer containing at least two epoxy groups in the molecule, a polymer or an oligomer produced by the ring-opening reaction of the epoxy group, and the like. Examples of the epoxy resin include, but are not limited to, dicyclopentadiene type epoxy resins, bisphenol type epoxy resins, biphenyl type epoxy resins, glycidyl ester type epoxy resins, ether ester type epoxy resins, novolac epoxy type epoxy resins, Type epoxy resin, an aliphatic epoxy resin, an aromatic epoxy resin, a polyaromatic epoxy resin, and the like.

The epoxy resin may be a non-modified multi-aromatic epoxy resin having an epoxy equivalent weight (EEW) of 150-400 g / eq and a softening point of 50-100 ° C.

In the present invention, when the dimeric acid-modified epoxy resin and the non-modified epoxy resin are mixed, the mixing ratio of the dimeric acid-modified epoxy resin and the non-modified epoxy resin may be 1.5-7: 1 by weight, 2-6: 1 weight ratio.

The content of the non-modified epoxy resin is not particularly limited, and can be appropriately adjusted in consideration of shrinkage and flexibility. For example, the non-modified epoxy resin may be used in an amount of 0.5-3% by weight based on the total weight of the epoxy resin composition.

Hardener

In the epoxy resin composition of the present invention, the curing agent is a component which reacts with an epoxy resin as a main resin to advance the curing of the composition. As the curing agent, a conventional curing agent known in the art for curing reaction with an epoxy resin can be used without limitation. As the semiconductor sealing curing agent, a phenol resin-based curing agent having excellent properties such as moisture resistance, heat resistance and preservability can be used.

The phenolic resin-based curing agent refers to all monomers, oligomers and polymers having at least one phenolic hydroxyl group per monomer, for example, two or more phenolic hydroxyl groups, and its molecular weight and molecular structure are not particularly limited. Non-limiting examples of usable phenolic resin-based curing agents include xylock-type phenol resin, polyaromatic phenol resin, polyfunctional phenol resin, phenol novolak type phenol resin, naphthalene type phenol resin, dicyclopentadiene type phenol resin, . These may be used singly or in combination of two or more.

For example, as the phenol resin-based curing agent, a polyaromatic phenol resin and a xylock-type phenol resin may be mixed in a weight ratio of 2-3: 1.

The hydroxyl group (OH) equivalent of the phenolic resin-based curing agent may be 90-250 g / eq, for example, 150-220 g / eq. The softening point of the phenolic resin-based curing agent may be 100 ° C or lower, for example, 60-80 ° C.

The content of the curing agent may be appropriately adjusted according to the content of the main resin. For example, the content of the curing agent may range from 3 to 6% by weight based on the total weight of the epoxy resin composition. When the content of the curing agent falls within the range described above, the flexural characteristics of the semiconductor device can be maintained at a satisfactory level, and reliability such as sufficient strength, hygroscopicity, and heat resistance can be secured.

Hardening accelerator

In the epoxy resin composition of the present invention, the curing accelerator is a component for promoting the curing reaction between the epoxy resin and the curing agent, and can be used without any limitations as commonly used in the art.

Non-limiting examples of available curing accelerators include imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole; Amine compounds such as triethylamine, tributylamine and benzyldimethylamine; Tertiary amine compounds such as 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol and 1,8-diazabicyclo (5,4,0) undec-7-ene; And organic phosphine compounds such as phenylphosphine, diphenylphosphine, triphenylphosphine, tributylphosphine and tri (p-methylphenyl) phosphine. The above-mentioned components may be used singly or in combination of two or more. For example, an organophosphine compound having excellent moisture resistance and heat hardness can be used.

In the present invention, the content of the curing accelerator may be appropriately controlled depending on the reactivity of the main resin or the curing agent. For example, the content of the curing accelerator may be in the range of 0.05-0.5 wt%, for example, 0.1-0.3 wt%, based on the total weight of the epoxy resin composition. When the content of the curing accelerator falls within the above-mentioned range, appropriate curability can be ensured.

Inorganic filler

In the epoxy resin composition of the present invention, the inorganic filler can be used as an inorganic filler applicable in the art as a component for improving the strength of the sealing material and lowering the moisture absorption amount.

Non-limiting examples of usable inorganic fillers include silica, silica nitride, alumina, aluminum nitride, boron nitride, and the like. The above-mentioned components may be used alone or in combination of two or more. For example, silica fillers such as natural silica, synthetic silica, and fused silica (high purity) can be used.

The average particle diameter of the inorganic filler is not particularly limited, and may be 1-50 占 퐉, for example, 1-30 占 퐉 as another example. The shape of the inorganic filler may be spherical, angular, or amorphous, and is not particularly limited thereto. For example, fused or synthetic silica having an average degree of sphericity of 0.92 or more and an average particle diameter of 1 to 30 mu m can be used as the filler.

The content of the inorganic filler is not particularly limited and may be, for example, in the range of 80 to 90% by weight based on the total weight of the epoxy resin composition. If the content of the filler is less than 80% by weight, the strength may be lowered and the adhesiveness may be lowered by increasing the moisture absorption amount. If the content of the filler exceeds 90% by weight, the viscosity may increase and the flowability may be deteriorated.

Other additives

The epoxy resin composition of the present invention may optionally further contain additives conventionally used in the field of encapsulants, so long as the inherent characteristics of the composition are not impaired.

Examples of usable additives include, but are not limited to, coupling agents, coloring agents, release agents, modifiers, flame retardants, low stressing agents, and mixtures of two or more thereof. The content of such an additive may be appropriately added within the range of contents known in the art, for example, it may be in the range of 0.1-10% by weight based on the total weight of the epoxy resin composition.

The coupling agent is a substance that imparts a bonding force between the resin components to be used and the inorganic filler, and those conventionally known in the art can be used. For example, a silane coupling agent such as an epoxy silane, an aminosilane, an alkylsilane, a ureide silane, or a vinyl silane, a titanate coupling agent, an aluminum / zirconium coupling agent, or a mercapto coupling agent may be used. The above-mentioned components may be used alone or in combination of two or more. The content of the coupling agent is not particularly limited, and may be in the range of 0.1-0.5 wt%, based on the total weight of the epoxy resin composition.

As the coloring agent, coloring agents such as carbon black, spinach, and other organic coloring agents may be used. The colorant may be used in an amount of 0.1-0.5 wt% based on the total weight of the epoxy resin composition, but is not particularly limited thereto.

The releasing agent is a material used for securing a releasing force that minimizes adherence to a mold after molding. As the releasing agent which can be used, natural wax, synthetic wax or a mixture thereof can be used. Natural waxes include carnauba wax and synthetic waxes include polyethylene wax. The content of the releasing agent is not particularly limited, and may be, for example, 0.1 to 0.5% by weight based on the total weight of the epoxy resin composition by mixing natural and synthetic waxes.

Modified silicone resin, modified polybutadiene and the like can be used as the low stress agent, and silicone powder and the like can be used as the modifier.

In order to impart flame retardancy, conventional flame retardants in the art can be used. Non-limiting examples of flame retardants that can be used include metal hydroxides, phosphorus and nitrogen containing organic compounds (such as resorcinol diphosphate, phosphate, phenoxyphosphazene, melamine cyanurate, cyanurate, phenolic melamine resin, or mixtures thereof. Examples of such metal hydroxides include hydroxides of metals selected from magnesium, calcium, strontium, barium, boron, aluminum and gallium.

The method for producing the epoxy resin composition of the present invention containing the above-mentioned components is not particularly limited and can be produced by a general method in the art. For example, it can be produced by a known melt-kneading method using a Banbury mixer, a kneader, a roll, a single or twin extruder, a cone, or the like.

<Semiconductor device>

The present invention provides a semiconductor device encapsulated using the above-described epoxy resin composition.

A semiconductor device to which the epoxy resin composition can be applied refers to an electronic circuit (integrated circuit) formed by integrating and wiring a transistor, a diode, a resistor, a capacitor, etc. on a semiconductor chip or a substrate. In one example, the semiconductor device may be a transistor, a diode, a microprocessor, a semiconductor memory, or the like.

The method for encapsulating and manufacturing a semiconductor device using the epoxy resin composition according to the present invention is not particularly limited and may be manufactured by a method known in the art. For example, it can be manufactured by encapsulating a semiconductor element by a molding method such as a transfer mold, a compression mold, or an injection mold.

Hereinafter, the present invention will be described more specifically by way of examples. However, the following examples are intended to assist the understanding of the present invention, and the scope of the present invention is not limited to the examples in any sense.

[ Example  1-3]

Specifications of raw materials constituting the epoxy resin composition of the present invention are shown in Table 1 below. An epoxy resin, a curing agent, a curing accelerator, an inorganic filler, and other components are blended according to the composition shown in Table 2 below, then melt-mixed at a temperature of 100-130 ° C using a melt kneader and cooled to room temperature, And then subjected to a blending process to prepare an epoxy resin composition of Example 1-3. In Table 2, the usage unit of each composition is% by weight.

[ Comparative Example  1-4]

An epoxy resin composition of Comparative Example 1-4 was prepared in the same manner as in Example 1 using an epoxy resin, a curing agent, a curing accelerator, an inorganic filler and other components according to the composition shown in Table 2 below.

[ Experimental Example . Property evaluation]

The physical properties of the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-4 were measured as follows, and the results are shown in Table 3 below.

(1) Flow measurement (spiral flow)

The epoxy resin composition prepared in each of the examples and the comparative examples was heat-transferred using a spiral flow mold (spiral flow mold of EMMI-I-66 standard) at a pressure of 70 kg / cm 2, a temperature of 175 ° C, 120 seconds) and the flowability of the product was measured.

(2) Gelation time

A small amount of the epoxy resin composition prepared in each of the Examples and Comparative Examples was spread over the gel timer widely and the time required for gelation of the product was measured.

(3) Glass transition temperature (Tg)

TMA (Thermomechanical Analyzer).

(4) Coefficient of linear expansion (Tg)

TMA (Thermomechanical Analyzer). ? 1 represents a coefficient of linear expansion at a temperature lower than Tg, and? 2 represents a coefficient of linear expansion at a temperature higher than Tg.

(5) Adhesion

The epoxy resin composition prepared in each of the Examples and Comparative Examples was molded under the conditions of a mold temperature of 175 캜 and a curing time of 120 seconds to obtain a disk-shaped cured specimen having a diameter of 30 mm and a thickness of 2.0 mm. The obtained specimens were placed in an oven at 175 ° C. and post-molded (PMC) for 4 hours. The samples were allowed to stand at 85 ° C./85% relative humidity for 168 hours and measured for weight change. .

&Quot; (1) &quot;

Absorption rate (%) = (weight of sample after moisture absorption - weight of sample before moisture absorption) / weight of sample before absorption of moisture X 100

(6) Shrinkage

The epoxy resin composition prepared in each of the Examples and Comparative Examples was molded under the conditions of a mold temperature of 175 캜 and a curing time of 120 seconds to calculate a curing shrinkage ratio according to the following formula (2).

&Quot; (2) &quot;

Cure shrinkage (%) = Mold size / Mold cavity dimensions X 100

(7) Warpage

Using a 225-pin BGA package (substrate: 0.36 mm thick BT resin substrate, package size 24x24 mm, thickness 1.17 mm, silicon chip: size 9x9 mm, thickness 0.35 mm) And molded under the conditions of a mold temperature of 175 캜 and a curing time of 120 seconds, cured at 175 캜 for 4 hours, and then cooled at room temperature. Thereafter, the displacement in the height direction was measured in a diagonal direction from the gate of the package using a surface roughing machine, and the largest value of the displacement difference was defined as a deflection amount. At this time, evaluation criteria of the bending characteristics were set to O: 0.1 mm or less,?: 0.1-0.2 mm, and X: 0.2 mm or more.

(8) Evaluation of delamination

The epoxy resin composition prepared in each of the Examples and Comparative Examples was molded using a QFN 10x10 semiconductor package and humidified for 168 hours at 85 ° C / 85% RH through a thermo-hygrostat after 4 hours of PMC, The occurrence of peeling at the interface between the semiconductor element and the cured product of the epoxy resin composition after the progress of the row was counted (total number of test semiconductor elements: 30). Ultrasonic microscopy was used for boundary separation analysis.

As a result of the experiment, Example 1-3 in which epoxy resin composition containing dimeric acid-modified epoxy resin was applied showed that stable flowability can be ensured even though a high amount of filler is used, and warpage characteristics and reliability It can be confirmed that both can be improved. On the other hand, in the case of not including the dimeric acid-modified epoxy resin (Comparative Example 1-4), it was found that the flexural characteristics and / or reliability were poor.

Claims (7)

An epoxy resin, a curing agent, a curing accelerator, and an inorganic filler,
Wherein the epoxy resin comprises a dimer acid-modified epoxy resin having a modification ratio of 5-15%. The epoxy resin composition according to claim 1, wherein the dimeric acid-modified epoxy resin is represented by the following formula (1)
[Chemical Formula 1]

In this formula,
R is a divalent group derived from dimer acid having 10-40 carbon atoms,
R ₁ , R ₂ and R ₃ are the same as or different from each other, and are each independently hydrogen or an alkyl group having 1-6 carbon atoms,
n is an integer of 0-5. The epoxy resin composition according to claim 1, wherein the dimeric acid-modified epoxy resin has a melt viscosity of 0.5 to 1.5 poise at 150 占 폚, a softening point of 55 to 65 占 폚, and an epoxy equivalent of 200 to 500 g / eq. The epoxy resin composition according to claim 1, wherein the epoxy resin further comprises a non-modified epoxy resin having a softening point of 50-100 DEG C and an epoxy equivalent of 150-400 g / eq. 5. The epoxy resin composition according to claim 4, wherein the mixing ratio of the dimeric acid-modified epoxy resin to the non-modified epoxy resin is 1.5-7: 1 by weight. The epoxy resin composition according to claim 1, wherein the epoxy resin composition comprises an epoxy resin containing 3-10 wt% of an epoxy resin, 3-6 wt% of a curing agent, 0.05-0.5 wt% of a curing accelerator, and 80-90 wt% Resin composition. A semiconductor device encapsulated with an epoxy resin composition according to any one of claims 1 to 6.