JP2012201695A - Epoxy resin composition for sealing and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress production of marks and smear on the internal surface of a mold due to transfer of a bleeding mold release agent component and production of smear and voids on a molded package surface, in package molding using an epoxy resin composition for sealing.SOLUTION: An epoxy resin composition for sealing includes an epoxy resin, a curing agent, an inorganic filler and a mold release agent, wherein the mold release agent includes (a) oxidized polyethylene, (b) natural carnauba wax and (c) at least one of hydroxystearic acid amide and montanic acid bisamide and the component (a) accounts for ≤50 mass% of the total mold release agent.

Description

  The present invention relates to an epoxy resin composition for sealing, and a semiconductor device sealed using the same.

  In recent years, many semiconductor device packages are manufactured by sealing a semiconductor element that has been bonded to a substrate using an epoxy resin composition for sealing. A typical manufacturing method in this case is a transfer molding method.

  In recent years, a semiconductor device package manufactured by a transfer molding method has been required to have a small outer dimension in response to a demand for reduction in size and weight of an electronic device. At the same time, the degree of integration of the packaged semiconductor elements themselves has increased, and the chip size has increased.

  For this reason, the epoxy resin composition for sealing is required to have excellent properties such as moisture resistance and heat resistance, and inorganic fillers have become highly blended. However, an epoxy resin composition that is highly blended with an inorganic filler has a low cure shrinkage during molding, but does not necessarily have good mold release properties.

  Therefore, it is considered to increase the amount of the release agent added or to mix a release agent system that easily oozes onto the mold surface (see Patent Documents 1 to 5).

JP 2003-246914 A JP 2004-059700 A Japanese Patent Laid-Open No. 2005-015633 JP 05-259316 A JP 2010-280805 A

However, in package molding using a sealing epoxy resin composition containing a mold release agent, the exuded mold release agent component is transferred to the inner surface of the mold, resulting in marks and stains. Dirt and voids are also easily formed on the package surface.
This invention is made | formed in view of such a situation, and makes it a subject to reduce and suppress the package surface stain | pollution | contamination and package hole which generate | occur | produce by shaping | molding of the epoxy resin composition for sealing.

In order to solve the above-mentioned problems, the epoxy resin composition for sealing of the present invention contains a release agent together with an epoxy resin, a curing agent, and an inorganic filler, and the release agent includes the following (a) and (b ), (C) component, and the component (a) is 50% by mass or less based on the total amount of the release agents.
(A) polyethylene oxide (b) natural carnauba (c) at least one of hydroxystearic acid amide and montanic acid bisamide

In this sealing epoxy resin composition, the total compounding amount of the release agent is preferably 0.03 to 3% by mass with respect to the entire sealing epoxy resin composition.
In this sealing epoxy resin composition, the release agent is blended in advance as a solidified product obtained by melting the three components (a), (b) and (c) by heating, mixing and cooling to room temperature. Preferably it is.
Furthermore, the epoxy resin composition for sealing preferably contains a coupling agent.
The semiconductor device of the present invention is sealed with the above-described sealing epoxy resin composition.

  In the semiconductor device package molding using the sealing epoxy resin composition of the present invention, the exudation of the release agent to the inner surface of the molding die is suppressed, and dirt and voids on the surface of the molded product package (void) Generation can be reduced or suppressed.

[Epoxy resin]
The epoxy resin of the epoxy resin composition for sealing of the present invention is not particularly limited, and any of various types including known ones can be used.
Examples thereof include epoxy resins such as O-cresol novolac type epoxy, biphenyl type epoxy, dicyclopentadiene type epoxy, bisphenol type epoxy, naphthol type epoxy, and bromine-containing epoxy. These can be used singly or in combination of two or more.

  It is considered that the compounding amount of the epoxy resin in the epoxy resin composition for sealing of the present invention is preferably in the range of 5 to 45% by mass with respect to the total amount of the epoxy resin composition. When used in such a range, the flow molding property of the sealing resin composition and the physical properties of the molded product are good.

[Curing agent]
The kind of the curing agent for the epoxy resin composition for sealing of the present invention is not particularly limited, and various kinds of known ones such as a phenol resin curing agent, an acid anhydride curing agent, an amine curing agent, and the like. Things can be used.

  In view of curability and physical properties of the cured product, a phenol resin curing agent is preferable. Examples thereof include various polyphenol compounds such as phenol novolak, cresol novolak, phenol aralkyl, biphenyl aralkyl, naphthol aralkyl, and naphthol compounds. These curing agents can be used singly or in combination of two or more.

  The compounding amount of the phenol resin-based curing agent in the epoxy resin composition is preferably such that the equivalent ratio of the phenolic hydroxyl group to the epoxy group (OH group equivalent / epoxy group equivalent) is in the range of 0.5 to 1.5. Considering the amount. More preferably, the amount is such that the equivalent ratio falls within the range of 0.8 to 1.2. When the equivalent ratio is within such a range, the curability of the epoxy resin composition can be increased, the glass transition temperature can be suppressed from decreasing, and the moisture resistance reliability can be increased. When other curing agents are used, it is considered that the chemical equivalent ratio between the reactive group of the curing agent and the epoxy group of the epoxy resin falls within the same range.

[Curing accelerator]
In the sealing epoxy resin composition of the present invention, what is called a curing accelerator can be used as a curing agent or in combination with a curing agent. Such a curing accelerator is not particularly limited, and various types including a known one can be used.

  Examples include tetraphenylphosphonium / tetraphenylborate and triphenylphosphine, other organic phosphines, tertiary amines such as diazabicycloundecene, and imidazoles such as 2-methylimidazole and 2-phenylimidazole.

These can be used singly or in combination of two or more.
The range of the blending amount of the curing accelerator in the epoxy resin composition is not particularly limited as long as it is an effective amount, but is usually within the range of 0.1 to 5% by mass, preferably within the range of the total amount of the epoxy resin composition. It is considered to be in the range of 0.5 to 2% by mass.

[Inorganic filler]
As the inorganic filler of the epoxy resin composition for sealing of the present invention, the kind thereof is not particularly limited, and various types including known ones can be used. Examples thereof include fused silica, crystalline silica, alumina, silicon nitride and the like, and these can be used alone or in combination of two or more. It is considered that the blending amount of the inorganic filler is preferably in the range of 70 to 90% by mass with respect to the total amount of the epoxy resin composition.

  Silica as an inorganic filler is preferable because it can reduce the coefficient of linear expansion of the obtained cured molded product. Among silicas, it is preferable to use fused silica in terms of high filling properties and high fluidity.

  As the fused silica, spherical fused silica or crushed fused silica can be used. Among them, it is particularly preferable to use spherical fused silica in consideration of fluidity. As the particle size of the fused silica, it is preferable to use one having an average particle size in the range of 5 to 70 μm. Furthermore, it is particularly preferable to use fine silica having an average particle size in the range of 0.5 to 2 μm because the fluidity is improved.

[Release agent]
In the epoxy resin composition for sealing of the present invention,
(A) a polyethylene oxide having an excellent performance to increase the releasability by interposing at the mold interface as a release agent;
(B) Natural carnava with good performance balance,
(C) Three components of hydroxystearic acid amide and montanic acid bisamide having good compatibility with the resin component are included at the same time.
And (a) polyethylene oxide is 50 mass% or less with respect to a mold release agent total.

  Each release agent used in combination is finely dispersed in the epoxy resin composition for sealing. In addition to excellent fluidity and mold release from molding, bleeding out of the entire mold release agent, transfer of the mold release agent to the mold, contamination of the molded product surface, generation of voids, etc. are reduced or suppressed. Is done.

  In addition, if a three-component release agent is melted and mixed in advance to prepare a solidified product, and the pulverized product is blended with other compounding materials to prepare an epoxy resin composition for sealing, each mold release The agent is further finely dispersed in the sealing epoxy resin composition. Thereby, since the above-described cooperative action is achieved with three components, the action and effect become more remarkable.

  (A) About the mixing | blending of polyethylene oxide, as mentioned above, although it shall be in the range of 1-50 mass% of mold release agent total amount, Preferably, it is 10-35 mass%, More preferably, it is the range of 15-30 mass%. It is considered to be within.

In addition, the component (b) and the component (c) of the release agent are each in the range of 10 to 60% by mass, more preferably in the range of 15 to 50% by mass with respect to the total amount of the release agent. It is considered.
And the total amount of the release agent containing the three components (a), (b) and (c) is preferably within a range of 0.03 to 3% by mass with respect to the total amount of the epoxy resin composition, More preferably, it is considered to be in the range of 0.1 to 1% by mass. Considering molding workability and the like, the total amount of the release agent containing the three components is preferably 0.03% by mass or more based on the total amount of the epoxy resin composition. In consideration of the smoothness of the surface of the molded product, 3% by mass or less is preferable with respect to the total amount of the epoxy resin composition.

[Polyethylene oxide]
As the oxidized polyethylene (oxidized PE), it is preferable to appropriately select and use numerical values such as a dropping point, an acid value, a number average molecular weight, a density, and an average particle diameter. The dropping point is preferably 100 to 130 ° C., the acid value is 10 to 70 mgKOH / g, the number average molecular weight is 800 to 3000, and the density is 0.8 to 1.1 g / cubic cm. The effect of improving the continuous moldability of the epoxy resin composition for sealing of the present invention is exhibited.

[Natural carnauba]
As the natural carnauba, those having a number average molecular weight of 340 to 820, a melting point of 82 to 86 ° C., and a specific gravity of about 0.99 to 1.00 are preferably used.

[Hydroxystearic acid amide]
In the epoxy resin composition for sealing of the present invention, hydroxystearic acid amide is particularly preferably used among the aliphatic amide release agents. Hydroxystearic acid amide is a so-called mold release agent, intervening at the mold interface to improve the mold release property, and has good compatibility with the resin component in the composition, thereby improving the fluidity of the resin composition.
For this reason, when used in combination with the above-described oxidized polyethylene wax and natural carnauba, it has an affinity with other mold release agents, and bleed-out of the entire mold release agent and transfer to the mold are suppressed.

  In particular, 12-hydroxystearic acid amide, which is an acid amidation product of 12-hydroxystearic acid having a hydroxyl group near the center of the aliphatic chain, has compatibility with a resin component due to the molecular structure having an aliphatic alcohol moiety. Since the resin composition is particularly excellent and has a high effect of increasing the fluidity of the resin composition, it has a further excellent effect when used in combination with oxidized polyethylene wax and natural carnauba.

[Montannic acid bisamide]
In the epoxy resin composition for sealing of the present invention, examples of suitable aliphatic amide release agents similar to hydroxystearic acid amide include methylene bis-montanic acid amide of montanic acid bisamide and ethylene bis-montanic acid amide.
Montanic acid bisamide has a structure of an alkylene fatty acid amide in which fatty acid amides are dimerized by a methylene chain, has a high melting point of 100 ° C. or higher, has excellent compatibility with resin components, and has an effect of increasing the fluidity of the resin composition. high. For this reason, when used in combination with polyethylene oxide wax and natural carnauba, bleeding out of the entire release agent and transfer to the mold are reduced or suppressed.

[Coupling agent]
As a coupling agent, it is considered that a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a zirconium coupling agent or the like is further blended.
When a silica-based inorganic filler is blended, a silane coupling agent is suitable. Examples include mercaptosilane such as γ-mercaptopropyltrimethoxysilane, glycidoxysilane such as γ-glycidoxypropyltrimethoxysilane, and aminosilane. These may be used alone or in combination of two or more.

By blending the coupling agent, the dispersibility and heat resistance of the inorganic filler and the tracking resistance of the resin molded product can be further enhanced.
In addition, although a coupling agent may be mix | blended at the time of preparation of the epoxy resin composition for sealing, if it applies beforehand to the surface treatment of an inorganic filler, it will be more effective.

[Other ingredients]
The sealing epoxy resin composition of the present invention can further contain other components within a range not impairing the effects of the present invention. Examples thereof include flame retardants such as magnesium hydroxide, aluminum hydroxide and red phosphorus, colorants such as carbon black, low stress agents such as silicone elastomers, inorganic ion trapping agents and the like. These may be used alone or in combination of two or more.

[Manufacture of epoxy resin composition for sealing]
In the production of the epoxy resin composition for sealing of the present invention, first, each component including the above epoxy resin is mixed using a mixer, a blender or the like until it becomes sufficiently uniform. Thereafter, the mixture is melt-mixed in a heated state by a kneader such as a hot roll or a kneader, cooled to room temperature, and then pulverized by a known means.

In addition, although the epoxy resin composition for sealing of this invention may be a powder form, in order to handle easily, it is good also as a tablet compressed into the dimension and mass which match | combine with molding conditions.
The sealing epoxy resin composition of the present invention has good moldability and releasability, and has little exudation of the release agent on the surface of the molded product, thereby reducing and suppressing contamination on the surface of the molded product. be able to.
Also, in the molding of semiconductor device packages, the molded product is smoothly released from the molding die, and is excellent in molding workability, and it is difficult for the mold release agent to remain or transfer on the mold side. Mold contamination is less likely to occur.

[Semiconductor device]
The semiconductor device of the present invention can be manufactured by sealing using the sealing epoxy resin composition obtained as described above.
As the semiconductor element, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, a solid-state imaging element, or the like can be used.

As a package form of the semiconductor device of the present invention, for example, a chip carrier with plastic lead (PLCC), a quad flat package (QFP), a thin quad flat package (TQFP), a small outline package (SOP) ), A small outline J-lead package (SOJ), a thin small outline package (TSOP), a surface mount package such as a tape carrier package (TCP).
Further, examples of the package form of the semiconductor device of the present invention include an area mounting type package such as a ball grid array (BGA) and an insertion type package such as a dual inline package (DIP).

A specific method for manufacturing the semiconductor device package of the present invention will be illustrated and described by a typical transfer molding method.
First, a lead frame on which a semiconductor element is mounted, a circuit board, and the like are installed in a mold cavity, and then a molten epoxy resin composition in a molten state is injected into the cavity at a predetermined pressure to melt the epoxy resin The semiconductor element is filled with the composition while being wrapped.
The injection pressure at this time can be appropriately set according to the epoxy resin composition, the type of the semiconductor device, and the like. For example, the mold temperature is, for example, 160 to 190 ° C., and the molding time is, for example, It can be set to 30 to 300 seconds or the like.

Next, after performing post-curing (post-cure) with the mold closed, the mold is opened to take out the molded semiconductor device package. Post-curing conditions can be set to 160 to 190 ° C. and 2 to 8 hours, for example.
The molded product package of the semiconductor device of the present invention has a smooth molding surface with suppressed void formation on the surface, and is densely molded with high filling, so it has high moisture resistance and heat resistance, and various physical properties Is stable and highly reliable. In addition, the molding workability is also excellent.

  Furthermore, the semiconductor device sealed with the sealing epoxy resin composition of the present invention has very little bleeding and contamination of the release agent on the molded package surface, and the molded product surface is smooth and clean. Even in processes such as reflow soldering and surface mounting, it is less likely to cause defects and has high performance and stability.

Examples and comparative examples are shown below.
<Example 1>
The following materials are adjusted according to the formulation shown in Table 1, mixed for 30 minutes with a blender, homogenized, kneaded and melted with two rolls heated to 80 ° C, extruded, cooled, and then pulverized to a predetermined particle size with a pulverizer Thus, a granular sealing epoxy resin composition was obtained.

(Epoxy resin)
O-cresol novolac type epoxy resin: “ESCN 195XL” epoxy equivalent 195 manufactured by Sumitomo Chemical Co., Ltd.
(Curing agent)
Phenol novolac resin: “Tamanol 752” hydroxyl equivalent 104 manufactured by Arakawa Chemical Co., Ltd.
(Inorganic filler)
Crystalline silica: “3K” average particle size 30 μm made by Tatsumori

(Polyethylene oxide)
Oxidized polyethylene wax: “PED-136” manufactured by Clariant
(Natural carnauba)
Natural carnauba wax: “F1-100” manufactured by Dainichi Chemical Co., Ltd.
(Hydroxystearic acid amide)
12-hydroxystearic acid amide: manufactured by Dainichi Chemical Industry Co., Ltd. (montanic acid bisamide)
Methylenebismontanamide: manufactured by Dainichi Chemical Co., Ltd.

(Coupling agent)
γ-glycidoxypropyltrimethoxysilane: “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.
(Coloring agent)
Carbon black: “MA600MJ” manufactured by Mitsubishi Chemical Corporation
<Example 2, Comparative Examples 1-6>
Each of the above materials was adjusted according to the formulation of Table 1, and a granular sealing epoxy resin composition was obtained in the same manner as in Example 1.

<Example 3>
In Example 3, three types of release agents (25% by mass of polyethylene oxide, 25% by mass of natural carnauba, 50% by mass of tan montanoic acid) having the same quantitative ratio as in Example 1 were previously melted at 120 ° C. After melt mixing for 15 minutes, the mixture was cooled to room temperature to prepare a melt-mixed solidified product. The pulverized product was added to a blender at the same blending ratio as in Example 1 together with other blended materials, mixed and homogenized for 30 minutes, then kneaded and melted with two rolls heated to 80 ° C., cooled, It grind | pulverized to the predetermined particle size with the grinder, and obtained the granular epoxy resin composition for sealing.

The following evaluation was performed using the epoxy resin compositions for sealing in Examples 1 to 3 and Comparative Examples 1 to 6 described above.
<Evaluation>
[Spiral flow]
Using a spiral flow measurement mold in accordance with ASTM D3123A, mold temperature: 175 ° C., injection pressure: 70 kgf / square cm, molding time: 90 seconds, post-curing: 175 ° C./6 h, sealing epoxy The resin composition was transfer molded and the flow distance (cm) was measured.

Spiral flow is a value that is a measure of moldability, and a longer flow distance (cm) indicates a molding material with better flowability.
[Geltime]
Using a curast meter, the curing torque of the sealing epoxy resin composition maintained at 160 ° C. was measured over time, and the time (s) until the curing torque value reached 0.1 kgf was measured as the gel time. A smaller value indicates faster curability.

[Package surface contamination]
An external dimension of 138 × 38, in which 30 evaluation chips of a size of 4 × 4 × 0.4 mmt are mounted on a glass base epoxy resin substrate (size of 140 × 50 × 0.5 mmt) in a matrix using silver paste. A 0.8 mmt batch sealed BGA (Ball Grid Array) package was transfer molded under the same conditions as in the spiral flow test, and the contamination of the package surface was visually confirmed.
○: Dirt is present ×: Dirt is absent

[Evaluation results]
When the evaluation result of Table 1 is seen, the epoxy resin composition (comparative examples 3-4) of the 2 component mold release agent which does not contain polyethylene oxide, the epoxy resin composition of the 2 component mold release agent which does not contain natural carnauba ( In Comparative Example 5), the epoxy resin composition (Comparative Example 6), which is a two-component release agent containing neither hydroxystearic acid amide nor montanic acid bisamide, shows package surface contamination.

Moreover, in the excess case (Comparative Examples 1-2) in which the oxidized polyethylene exceeds 50% by mass, the package surface contamination is still seen even with the epoxy resin composition containing the three-component release agent at the same time.
In Example 3, Example 2, and Example 3 of an epoxy resin composition in which three kinds of release agents having the same amount ratio as in Example 1 were previously melt-mixed to prepare a solidified product and the pulverized product was blended. It was confirmed that no package surface contamination was observed, the spiral flow value was high, and the fluidity during molding was excellent. In particular, in Example 3, all of the suppression of package surface contamination, the spiral flow value, and the gel time were excellent. Further, when the package surface was scrutinized, fine irregularities derived from the undissolved part of the release agent were not observed.

Claims (5)

An epoxy resin composition for sealing containing a release agent together with an epoxy resin, a curing agent, and an inorganic filler, wherein the release agent includes the following components (a), (b), and (c): An epoxy resin composition for sealing, wherein a) is 50% by mass or less based on the total amount of release agents.
(A) polyethylene oxide (b) natural carnauba (c) at least one of hydroxystearic acid amide and montanic acid bisamide   2. The sealing epoxy resin composition according to claim 1, wherein a total amount of the release agent is 0.03 to 3% by mass with respect to the entire sealing epoxy resin composition.   The release agent is blended in advance as a solidified product obtained by melting and mixing the three components (a), (b), and (c) in advance and cooling them to room temperature. The epoxy resin composition for sealing as described.   The sealing epoxy resin composition according to claim 1, further comprising a coupling agent.   A semiconductor device sealed with the sealing epoxy resin composition according to claim 1.