JPH0841292A - Production of epoxy resin composition and epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To obtain the composition having low viscosity, high fluidity, adhesion and moldability by blending an epoxy resin, a curing agent and an inorganic filler with a curing derivative and a silane coupling agent in separate blending processes. CONSTITUTION:(A) An epoxy resin which is preferably a biphenyl type epoxy resin of the formula (R1 is H, a halogen or a 1-5C alkyl such as methyl or ethyl; (q) is an integer of 0-5) and has crystallizability at room temperature and <=80cp viscosity when dissolved in m-cresol in 30wt.% concentration, (B) a curing agent and (C) an inorganic filler in an amount of >=85%, based on the whole composition are blended with (D) a curing catalyst and (E) a silane coupling agent in separate blending processes, respectively. Preferably the component D is premixed with the components A, B and C and the mixture is blended with the component E.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention provides a cured product having a low viscosity, a high fluidity, an effect of suppressing the generation of voids, excellent moldability, adhesiveness and reflow resistance. The present invention relates to a method for producing an epoxy resin composition that can be industrially advantageously obtained, and an epoxy resin composition for semiconductor encapsulation.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As an epoxy resin composition used for semiconductor encapsulation, it is general to mix an epoxy resin with a phenol resin as a curing agent and silica as an inorganic filler. Since such an epoxy resin composition has a low viscosity when melted and a high fluidity as compared with other thermosetting resin compositions such as a phenol resin composition, it is suitable for use in LSIs, ICs, transistors, etc. It is effective in suppressing damage to fine patterns and wires and improving moisture resistance, therefore
It is preferably used for semiconductor encapsulation.

Further, as a recent trend, along with the increase in size of silicon chips and the miniaturization of wiring width, it has been demanded that the expansion coefficient of a semiconductor encapsulating material be close to that of a silicon chip. Therefore, an epoxy resin composition is required. The expansion coefficient of the cured product is lowered by increasing the blending amount of the filler.

On the other hand, on the other hand, since the package is becoming larger and the number of pins is increasing, a higher fluidity of the sealing material is also desired. Generally, however, as the amount of the filler is increased, the epoxy resin composition is increased. Liquidity will be poor. Therefore, in order to improve the fluidity, a low-viscosity biphenyl type epoxy resin is used as an epoxy resin to improve the fluidity characteristics, but in this case, many voids are generated inside the package during molding. There is such a problem.

Therefore, it has been desired to develop an epoxy resin composition which is free from the above problems and which is suitable for semiconductor encapsulation.

The present invention has been made in view of the above circumstances.
It is possible to industrially advantageously obtain an epoxy resin composition that has a low viscosity and high fluidity, has excellent moldability with almost no molding defects such as void formation during molding, and gives a cured product with a low expansion coefficient. An object of the present invention is to provide a method for producing an epoxy resin composition which can be used, and a semiconductor encapsulating epoxy resin composition obtained by the method.

[0007]

Means and Actions for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has blended an epoxy resin, a curing agent, an inorganic filler, a curing catalyst and a silane coupling agent. When producing an epoxy resin composition, by adding a curing catalyst and a silane coupling agent in separate kneading steps, respectively, having the above excellent properties, suitable epoxy resin composition as a resin for semiconductor encapsulation, Further, the production method of the present invention can be obtained industrially advantageously, and in particular, the inorganic filler is contained in an amount of 85% by weight or more with respect to the total composition, and is in a molten state (25 ° C., 30 ° C.) to meta-cresol. Epoxy resin having a viscosity of 80 centipoise (cp) or less in (wt% meta-cresol) and having crystallinity at room temperature, particularly biphenyl type epoxy resin is used. Alkoxy and finding that it is advantageous for the production of the resin composition, the present invention has been accomplished.

That is, the present inventor has studied the causes of the above-mentioned voids and the like, and as a result, it has been confirmed that a silane coupling agent which is usually added to an epoxy resin composition as an adhesive component and a curing catalyst which is added to accelerate the curing. There is a problem in interaction, and in the production of an epoxy resin composition, usually, all components including a silane coupling agent and a curing catalyst are kneaded at the same time. However, when all components of an epoxy resin composition are mixed and kneaded at once. Since the reactive group in the molecule of the silane coupling agent locally reacts via the curing catalyst to promote the generation of volatile components such as alcohol, the cured product of this epoxy resin composition has a volatile component in the resin. It may not be completely melted, which may cause internal voids or may cause speckled appearance defects on the surface of the cured product. This phenomenon is especially caused by high filling of the inorganic filler. The or using a biphenyl type epoxy resin as the epoxy resin, and was found that becomes remarkable when increasing the curing catalyst amount.

As a result of repeated studies to solve this point, the addition of the curing catalyst and the silane coupling agent in separate kneading steps reduces the direct contact between both components and increases the dispersibility. Therefore, the epoxy resin composition obtained by this production method uses a biphenyl type epoxy resin and has a low viscosity and a high fluidity even when highly filled with an inorganic filler. Also, it has good filling property in thin layer, excellent adhesiveness to IC substrate and moldability, almost no molding defects such as void formation during molding, excellent reflow resistance, and expansion coefficient. Has been found to give a low cured product.

Therefore, according to the present invention, when an epoxy resin composition containing an epoxy resin, a curing agent, an inorganic filler, a curing catalyst and a silane coupling agent is produced, the curing catalyst and the silane coupling agent are separately provided. A method for producing an epoxy resin composition, which comprises adding the epoxy resin, a curing agent, an inorganic filler, a curing catalyst, and a silane coupling agent. As a material having crystallinity at room temperature and having a viscosity of 80 cp or less when dissolved in meta-cresol at a concentration of 30% by weight, the inorganic filler is used in a proportion of 85% by weight or more of the entire composition. Provided is an epoxy resin composition for semiconductor encapsulation, which is characterized by containing and obtained by the method described above.

The present invention will be described in more detail below. The epoxy resin composition according to the present invention comprises an epoxy resin, a curing agent, an inorganic filler, a silane coupling agent and the like.

Here, as the first component epoxy resin, an epoxy resin having at least two epoxy groups in one molecule can be blended, and specifically, bisphenol A type epoxy resin, orthocresol novolac type. Epoxy resin, phenol novolac type epoxy resin, allylphenol novolac type epoxy resin, alicyclic epoxy resin, substituted or unsubstituted triphenol alkane type epoxy resin and its polymer, biphenyl type epoxy resin, naphthalene ring-containing epoxy resin, di Examples thereof include a cyclopentadiene type epoxy resin, a phenol aralkyl type epoxy resin, a heterocyclic type epoxy resin, and an epoxy resin obtained by introducing a halogen atom into these.

In the present invention, as the epoxy resin, an epoxy resin having a particularly low viscosity, in particular, a viscosity of 80 centipoise (cp) or less, particularly 30 to 75c in a melt state (25 ° C., in 30% by weight metacresol) to metacresol.
It is preferable to use an epoxy resin having p and crystallinity at room temperature from the viewpoint of improving the performance of the composition. When the molten state of the epoxy resin is 80 cp or less,
Silica can be highly filled, and the composition can have a low water absorption coefficient and a low linear expansion coefficient. If it exceeds 80 cp, the above properties may not be sufficiently obtained, and even if the molten state is 80 cp or less, the room temperature is low. Those having no crystallinity may be inferior in workability and dispersibility with other components. Specific examples of such an epoxy resin include the following compounds.

[0014]

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[0015]

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Among these, the biphenyl type epoxy resin represented by the following general formula (1) is preferably used as the epoxy resin.

[0017]

[Chemical 3] (Wherein R ¹ is a hydrogen atom, a halogen atom or a monovalent hydrocarbon group having 1 to 5 carbon atoms, for example, a methyl group, an ethyl group,
It is an alkyl group such as a butyl group, and q is an integer of 0 to 5. )

The blending ratio of the biphenyl type epoxy resin of the above formula (1) is 20 to 95% (wt%, the same applies hereinafter), especially 40 to 90% of the total epoxy resin blended in the composition.
It is preferable to set it as the range. If the compounding amount of the biphenyl type epoxy resin of the formula (1) is less than 20%, low moisture absorption cannot be obtained, crack resistance at the time of thermal shock after moisture absorption cannot be sufficiently improved, and high fluidity can be obtained. Since it is not present, it may be inferior in moldability and curing characteristics, and if it exceeds 95%, the glass transition temperature and the resin strength may be lowered, which may be disadvantageous.

Next, the curing agent of the second component is not particularly limited and can be appropriately selected according to the epoxy resin to be used. For example, amine curing agent, acid anhydride curing agent, phenol novolac. Type curing agent, resol type phenol resin, triphenol alkane type resin, polyfunctional type phenol resin, dicyclopentadiene type phenol resin, naphthalene ring-containing phenol resin, phenol aralkyl resin, and the like. Among these, naphthalene ring containing phenol Resins and phenol aralkyl resins are preferably used.

Examples of the naphthalene ring-containing phenol resin and the phenol aralkyl resin include the following compounds.

[0021]

[Chemical 4] (However, R ¹ and m each have the same meaning as described above, and k
And g are 0 or an integer of 1 or more, and p is an integer of 1 or more. )

[0022]

[Chemical 5]

The amount of the above-mentioned naphthalene ring-containing phenol resin and phenol aralkyl resin is 10 to 90%, especially 20 to 90% of the total phenol resin compounded as the curing agent.
70% is preferable, and if it is less than 10%, low hygroscopicity may not be obtained, and if it exceeds 90%, Tg may decrease and heat resistance may deteriorate.

In the present invention, the curing agent can be used in a usual amount. For example, in the case of a phenol resin, the above epoxy resin and phenol resin are mixed with the amount (a) of epoxy groups in the epoxy resin and the phenol in the phenol resin. The ratio with the amount (b) of the functional hydroxyl group is preferably a / b = 0.5 to 1.5, particularly preferably 0.8 to 1.2,
If the compounding ratio is out of the above range, the curability, crack resistance and hygroscopicity may be poor.

In the present invention, as the inorganic filler of the third component, those usually blended in the epoxy resin composition can be used. Specific examples thereof include fused silica, silicas such as crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, and glass fiber. Among them, fused silica is preferable.

The average particle size and shape of these inorganic fillers are not particularly limited, but as fused silica, the average particle size is from 3 to 3.
The thickness is preferably 15 μm, and a spherical shape is preferably used in order to increase the packing density and reduce the stress on the chip surface. The inorganic filler is preferably surface-treated in advance in order to increase the bonding strength between the resin and its surface. Further fine silica (average particle size 0.5 to
The resin strength can be further improved by adding a small amount of 3 μm).

The above-mentioned inorganic fillers may be used alone or in combination of two or more, and the compounding amount thereof is not particularly limited, but the total amount of the epoxy resin and the phenol resin is 100 parts (parts by weight, The same applies hereinafter) to 100 to 130
It is preferably 0 part, particularly preferably 200 to 900 parts.

In the present invention, the inorganic filler can be highly filled, and the inorganic filler can be blended in an amount of 85% by weight or more based on the entire composition.

Further, as the curing catalyst which is the fourth component,
Examples include various curing accelerators such as imidazole compounds, tertiary amine compounds, phosphine compounds, and cycloamidine compounds. The compounding amount of the curing catalyst is not particularly limited, but the total amount of the epoxy resin and the phenol resin is 100.
It is preferably 0.2 to 5 parts, especially 0.4 to 3 parts with respect to parts.

As the silane coupling agent as the fifth component, an organosilicon monomer having two or more different reactive groups in the molecule can be used, and one reactive group includes an epoxy group, a vinyl group, Those having a methacryl group, an amino group, a mercapto group and the like and a methoxy group, an ethoxy group, a cellosolve group and the like as the other reactive group can be mentioned. Specifically, the following compounds can be exemplified, but among them, those containing an epoxy group are particularly preferably used.

[0031]

[Chemical 6]

The composition of the present invention may further contain various other additives, if desired. For example, a thermoplastic resin, a thermoplastic elastomer, an organic synthetic rubber, a silicone-based low stress agent, and carnauba wax. Waxes such as
Mold release agents such as fatty acids such as stearic acid and metal salts thereof (carnauba wax is preferably used from the viewpoint of adhesiveness and mold release), pigments such as carbon black, cobalt blue and red iron oxide, antimony oxide, halogen compounds One or more of flame retardants such as, surface treatment agents such as alkyl titanates, and additives such as antiaging agents can be blended.

In the method for producing an epoxy resin composition of the present invention, when producing an epoxy resin composition containing each of the above-mentioned components, a curing catalyst as a fourth component and a silane coupling agent as a fifth component among the components are prepared. And are added in separate kneading steps.

In this case, the method for adding the curing catalyst and the silane coupling agent is not particularly limited unless they are added simultaneously.
A method of separately adding a curing catalyst and a silane coupling agent and kneading with other components, a method in which the curing catalyst is melt-mixed in advance with the phenol resin or uniformly dispersed on the silica surface and added, and kneaded with other components A method, a method in which a silane coupling agent is uniformly dispersed in an epoxy resin or a phenol resin in advance and added, and kneading with other components can be adopted. Specifically, among the components described above as the first kneading step, the fourth component, the curing catalyst, the fifth component
A predetermined amount of either one of the silane coupling agents, which is a component, is uniformly stirred and mixed with the other components, and 70-
After kneading with a kneader heated to 95 ° C., a roll, an extruder, etc., cooling, pulverizing, etc., a second predetermined kneading step is carried out by uniformly stirring the other predetermined amount in the same manner as above, It can be manufactured by the steps of mixing, kneading with a kneader, roll, extruder or the like which has been preheated to 70 to 95 ° C., cooling, and pulverizing.

Among these methods, a method in which the curing catalyst is mixed and kneaded with other components other than the silane coupling agent, and then the silane coupling agent is added and kneaded is used to reduce the occurrence of voids and to reduce the IC substrate. It is a particularly effective and effective method for improving the adhesiveness with. Also in this case,
The curing catalyst may be kneaded with a part of the components other than the silane coupling agent, the silane coupling agent may be kneaded with the rest of the other components, and the mixture may be kneaded.

The epoxy resin composition of the present invention thus obtained can be effectively used for encapsulating a semiconductor device such as SOP, SOJ, TSOP, and TQFP. Here, when encapsulating the semiconductor device, A conventionally used molding method such as transfer molding or casting can be used. In this case, it is desirable that the molding temperature of the epoxy resin composition is 150 to 180 ° C. for 30 to 180 seconds, and the post cure is 150 to 180 ° C. for 2 to 16 hours.

[0037]

EFFECT OF THE INVENTION According to the method for producing an epoxy resin composition of the present invention, the viscosity is low, the fluidity is high, the adhesiveness is excellent, and molding defects such as voids during molding hardly occur and the moldability is excellent. In addition, an epoxy resin composition which gives a cured product having a low expansion coefficient can be industrially advantageously obtained. Therefore, the semiconductor device sealed with the cured product of the epoxy resin composition obtained by this manufacturing method has high reliability.

[0038]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. All parts in each example are parts by weight.

[Examples and Comparative Examples] Epoxy resins and phenolic resins shown below were added in amounts shown in Table 1, 1 part of triphenylphosphine as a curing catalyst, 0.65 parts of the curing catalyst 1 shown below, and antimony trioxide. 10 parts, carnauba wax 1.2 parts, γ-glycidoxypropyltrimethoxysilane as a silane coupling agent 1.5 parts, carbon black 1 part, fused spherical silica (I) 35 shown below.
Using 0 parts, 350 parts of fused spherical silica (II), and 80 parts of fused spherical silica (III), kneading was carried out by the following production methods (Production Methods A to E) as shown in Table 1 to obtain 11 kinds of epoxies. Resin compositions (Examples 1 to 8 and Comparative Examples 1 to 3) were obtained.

[0040]

[Chemical 7]

Curing catalyst 1: 1,8-diazabicyclo (5.4.0) undecene-7 and phenol novolac resin (TD2131 manufactured by Dainippon Ink and Chemicals) were mixed at a weight ratio of 20/80 and 130 ° C. After heating and melting for 30 minutes, crushed to 50 microns or less. Fused spherical silica: (I) Spherical silica having a specific surface area of 1.4 m ² / g and average particle size of 15 μm (II) Spherical silica having a specific surface area of 2.5 m ² / g and average particle size of 10 μm (III) Specific surface area of 10 m ² / g, average particle size 1.0 μm
Spherical silica Production method A: Epoxy resin, phenol resin, silica, curing catalyst, antimony trioxide, carnauba wax, and carbon black are uniformly mixed in a predetermined amount by stirring to 70 to 9 in advance.
The mixture is kneaded by an extruder heated to 5 ° C., expanded into a sheet, cooled, and pulverized. A predetermined amount of the silane coupling agent is uniformly stirred and mixed with the pulverized composition, and the mixture is kneaded again with an extruder that has been preheated to 70 to 95 ° C, and the sheet-shaped product is cooled and pulverized to form a composition. Get things. Production method B: A composition is obtained in the same manner as in production method A except that carnauba wax is added at the same time as the silane coupling agent. Production method C: Epoxy resin, phenol resin, silica, antimony trioxide, carnauba wax, carbon black, and silane coupling agent are uniformly stirred and mixed in a predetermined amount, and kneaded by an extruder heated to 70 to 95 ° C in advance. Then, the rolled sheet is cooled and crushed. A predetermined amount of the curing catalyst is uniformly stirred and mixed with the pulverized composition, and the mixture is kneaded again with an extruder that has been preheated to 70 to 95 ° C, and the sheet-shaped product is cooled and pulverized to obtain a composition. obtain. Production method D: Epoxy resin, phenol resin, silane coupling agent, a predetermined amount, melt-mixed with a kneader preheated to 70 to 110 ° C., cooled and pulverized,
A predetermined amount of silica, curing catalyst, antimony trioxide, carnauba wax, and carbon black are uniformly stirred and mixed,
Knead with an extruder that has been heated to 70 to 95 ° C in advance,
A sheet-shaped product is cooled and pulverized to obtain a composition. Production method E: Epoxy resin, phenol resin, silica, curing catalyst, antimony trioxide, carnauba wax, carbon black, silane coupling agent are mixed in a predetermined amount with uniform stirring, and extruded by heating to 70 to 95 ° C in advance. The mixture is kneaded in a machine and rolled into a sheet, which is then cooled and ground to obtain a composition.

The following tests were conducted on the obtained composition. The results are also shown in Table 1. (A) Spiral flow 175 ° C, 70k using a mold conforming to EMMI standard
It was measured under the condition of gf / cm ² . (B) Flexural strength and flexural modulus 180 ° C., 70 kg / cm according to JIS-K6911
^2. A bending test piece of 10 × 4 × 100 mm was molded under the condition of a molding time of 2 minutes, and post-cured at 180 ° C. for 4 hours, and then measured at room temperature. (C) Expansion coefficient, glass transition temperature Using a test piece having a diameter of 4 mm and a length of 15 mm, the value when the temperature was raised at a rate of 5 ° C. per minute by the TMA method was measured. (D) Adhesiveness A cylindrical molded product having a diameter of 15 mm and a height of 5 mm is molded on a 42 alloy plate under the conditions of 175 ° C., 70 kg / cm ² and a molding time of 2 minutes, post-cured at 180 ° C. for 4 hours, and then push-pull. The amount of peeling between the molded product and the 42 alloy plate was measured with a gauge. (E) Solder crack resistance after moisture absorption (reflow resistance) Silicone chips with a size of 7 × 7 × 0.4 mm
It was adhered to a lead frame for QFP (42 alloy) having a size of × 14 × 1.4 mm, and the epoxy resin composition was molded on this under the molding conditions of 175 ° C., 70 kg / cm ² , and a molding time of 2 minutes. Post cure at 4 ° C for 4 hours.
This was placed in an atmosphere of 85 ° C / 85% RH for 48 hours and 72 hours.
After leaving for a while, soak in a solder bath at 240 ℃ for 30 seconds,
The number of package cracks / total number was measured. (F) Void generation 7 × 7 × 0.4mm silicon chip 10 ×
It is adhered to a lead frame for QFP (42 alloy) having a large size of 14 × 1.4 mm, and the epoxy resin composition is molded on this under the molding conditions of 175 ° C., 70 kg / cm ² , and the molding time of 2 minutes. Post cure at 4 ° C for 4 hours.
Using an ultrasonic flaw detector, the number of internal voids (5φ or more) reflected on the frame / one package was measured. (G) Moisture resistance A 4MRAM chip is adhered to a 20-pin SOJ frame, and an epoxy resin composition is applied to this, under molding conditions of 175 ° C and 7
Molding under the conditions of 0 kg / cm ² and molding time of 2 minutes, 180
Post-cured at 4 ° C. for 4 hours. This is 121 ° C / 10
After leaving it in an atmosphere of 0% RH for 24 hours to absorb moisture, 2
Immerse in a solder bath at 60 ° C for 10 seconds, and further heat at 121 ° C / 10
The number / total number of breaks in the AI wiring when left in a 0% RH atmosphere for 300 hours was measured. (H) Water absorption rate Molded under the conditions of molding time of 175 ° C, 70 kg / cm ² , molding time of 2 minutes, and post-cured at 180 ° C for 4 hours. A disc having a diameter of 50 mm and a thickness of 2 mm was 121 ° C / 100% R.
The sample was left in an H 2 atmosphere for 24 hours, and the water absorption rate was measured.

From the results shown in Table 1, the epoxy resin composition obtained by the production method of the present invention has low viscosity and high fluidity,
Further, it was confirmed that it gives a cured product having an effect of suppressing the generation of voids, excellent moldability, adhesiveness and reflow resistance.

[0044]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 23/31 // B29C 45/14 8823-4F B29K 63:00 (72) Inventor Eiichi Asano Gunma Prefecture Usui-gun Matsuida-cho 1 Oji Hitomi, Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Kazutoshi Tomiyoshi Katsumi-gun Matsuida-cho Oji Hitomi 1 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Inside the Technical Research Institute (72) Hatsuji Shiraishi, 1 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture 10 Shin-Etsu Chemical Co., Ltd. Research Center for Silicone Electronic Materials (72) Inventor Toshio Shiobara Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Address 1 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (3)

[Claims] 1. When producing an epoxy resin composition comprising an epoxy resin, a curing agent, an inorganic filler, a curing catalyst and a silane coupling agent, the curing catalyst and the silane coupling agent are mixed in separate kneading steps. A method for producing an epoxy resin composition, which comprises adding. 2. The epoxy resin composition according to claim 1, wherein a curing catalyst and a part or all of components other than the silane coupling agent are kneaded, and then the silane coupling agent is added and kneaded. Manufacturing method. 3. An epoxy resin composition comprising an epoxy resin, a curing agent, an inorganic filler, a curing catalyst and a silane coupling agent, which has crystallinity at room temperature as an epoxy resin and 30% by weight of meta-cresol. The viscosity is 80 cp or less when dissolved at a concentration of, and an inorganic filler is contained in a proportion of 85% by weight or more of the entire composition, and obtained by the method according to claim 1 or 2. An epoxy resin composition for semiconductor encapsulation.