JP2002053734A - Epoxy resin composition for sealing semiconductor, and semiconductor device made by using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition for sealing a semiconductor, which is excellent in flame retardancy, flowability and moisture resistance. SOLUTION: The epoxy resin composition contains (A) an epoxy resin, (B) a phenol resin, (C) a polyhedral metal hydroxide represented by the formula: M1-XQX(OH)2 (wherein M stands for at least one metal atom selected from the group consisting of Mg, Ca, Sn and Ti atoms; Q stands for at least one metal atom selected from the group consisting of Mn, Fe, Co, Ni, Cu and Zn atoms; and X is a positive number of 0.01 to 0.5), (D) an ion acceptor, and (E) a flame retardant based on red phosphorus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation having excellent moisture resistance and flame retardancy, and a semiconductor device using the same.

[0002]

2. Description of the Related Art Semiconductor devices such as transistors, ICs, and LSIs have conventionally been sealed with an epoxy resin composition to form electronic components. It is indispensable that this electronic component complies with UL94 V-0, which is a standard of flame retardancy, and until now, in order to impart its flame retardant action, antimony compounds such as brominated epoxy resin and antimony oxide have been used. Has been adopted.

However, recently, from the viewpoint of environmental protection, a flame-retardant epoxy resin composition having a flame retardancy without using a halogen-based flame retardant or antimony oxide has been demanded.

[0004]

In response to this requirement, for example, a red phosphorus compound is used as a flame retardancy-imparting agent so as to provide flame retardancy in a range where the number of added parts is relatively small. There are many. As the reason, a hydroxyl compound or a boron-based compound or the like generally used as another flame retardant imparting agent requires a larger number of added parts for imparting its flame retardancy than the red phosphorus-based compound. . As a result, the epoxy resin composition as a sealing material has a decrease in fluidity and an increase in impurities, resulting in a decrease in moisture resistance reliability, which makes actual use difficult. However, as described above, the red phosphorus-based compound requires a relatively small number of added parts as compared with other compounds, but still has a problem in that the reliability of moisture resistance is lowered due to precipitation of impurities.

The present invention has been made in view of such circumstances, and an epoxy resin composition for semiconductor encapsulation which has excellent fluidity and excellent moisture resistance and flame retardancy and the reliability obtained by using the same. It is intended to provide a high semiconductor device.

[0006]

In order to achieve the above object, the present invention provides, as a first gist, an epoxy resin composition for semiconductor encapsulation containing the following components (A) to (E).

(A) Epoxy resin. (B) a phenolic resin. (C) A polyhedral metal hydroxide represented by the following general formula (1).

Embedded image (D) an ion scavenger. (E) Red phosphorus-based flame retardant.

Further, a semiconductor device in which a semiconductor element is encapsulated by using the above-mentioned epoxy resin composition for encapsulating a semiconductor is a second semiconductor device.
The summary of the

The polyhedral metal hydroxide of the component (C) in the epoxy resin composition for semiconductor encapsulation of the present invention has a hexagonal plate shape as shown in FIG.
Alternatively, it does not have a so-called thin plate-like crystal shape, such as a flake shape, and has a large crystal growth in the thickness direction (c-axis direction) both vertically and horizontally.
A plate-shaped crystal has a granular crystal shape that is more three-dimensionally and spherically shaped by growing in the thickness direction (c-axis direction), for example, a substantially dodecahedral, a substantially octahedral, or a substantially tetrahedral shape. It refers to metal hydroxide, usually a mixture thereof. Of course, in addition to crystal growth, the shape of the polyhedron changes due to pulverization, grinding, and the like, and the polyhedron can be approximated more three-dimensionally and spherically. FIG. 1 shows an example of a scanning electron micrograph (magnification: 50,000) showing the crystal shape of the polyhedral metal hydroxide. Thus, in the present invention, by using the above-mentioned polyhedral metal hydroxide, to a thing having a hexagonal plate shape as in the past, or to a thing having a plate-like crystal shape, such as a flake shape In comparison, a decrease in the fluidity of the resin composition can be suppressed.

[0010] The shape of the metal hydroxide of the present invention will be described in more detail with an example of a substantially octahedral shape. That is, an octahedral shape which is an example of the metal hydroxide of the present invention is composed of two parallel upper and lower base surfaces and six outer peripheral pyramid surfaces, and the pyramid surface is an upward inclined surface and a downward inclined surface. Have an octahedral shape alternately arranged.

More specifically, a conventional thin plate-shaped crystal having a thin plate shape has, for example, a hexagonal crystal structure, as shown in FIG.
Upper and lower 2 represented by (00 · 1) plane in the Bravais index
It has a hexagonal prism shape whose outer periphery is surrounded by a base surface 10 of the surface and six square cylinder surfaces 11 belonging to a {10.0} mold surface. And
Since there is little crystal growth in the [001] direction (c-axis direction), it has a thin hexagonal column shape.

On the other hand, as shown in FIG. 4, the metal hydroxide of the present invention controls (00) by controlling the crystal habit during crystal growth.
・ 1) The base surface 12 of the upper and lower surfaces represented by the plane, and $ 10
The outer circumference is surrounded by six pyramidal surfaces 13 belonging to a 1 ° mold surface. The pyramid surface 13 has a special crystal habit in which upward inclined surfaces 13a such as (10-1) planes and downward inclined surfaces 13b such as (10-1) planes are alternately arranged. 8
It has a planar shape. Further, the crystal growth in the c-axis direction is larger than that of the conventional one. FIG. 4 shows a plate-like shape, but FIG. 5 shows that the crystal growth in the c-axis direction further progressed and the crystal habit became remarkable and became isotropic. As described above, the metal hydroxide of the present invention includes those having a shape close to a regular octahedron. That is, the ratio of the major axis diameter of the basal plane to the thickness between the basal planes (major axis diameter / thickness) is 1
To 9 are preferred. 7 is more preferable as the upper limit of the ratio between the major axis diameter and the thickness. The mirror
In the Bravais index, “1 bar” is indicated as “−1”.

As described above, it can be understood from the following that the six surfaces surrounding the outer periphery of the metal hydroxide of the present invention are pyramidal surfaces belonging to {10 · 1}. That is, when the crystal of the metal hydroxide of the present invention is observed from the c-axis direction with a scanning electron microscope, the crystal has a three-fold rotational symmetry with the c-axis as a rotation axis. Further, the calculated value of the angle between the (10 · 1) plane and the {10 · 1} mold plane using the measured value of the lattice constant by powder X-ray diffraction is the value of the angle between the planes in the scanning electron microscope observation. It almost matches the measured value.

Further, the metal hydroxide according to the present invention comprises powder X
Half width B of (110) plane peak in X-ray diffraction
₁₁₀And the half width B of the peak of the (001) plane₀₀₁And the ratio
(B₁₁₀/ B ₀₀₁) Is 1.4 or more. This thing
Also, the crystallinity in the c-axis direction is good, and the thickness grows.
Can be confirmed. That is, the conventional hydroxide mug
In crystals such as nesium, crystals grow in the c-axis direction.
The peak of the (001) plane is broad and the half width B₀₀₁
Also increases. Therefore, (B₁₁₀/ B₀₀₁)
Become smaller. In contrast, in the metal hydroxide of the present invention,
(001) peak due to good crystallinity in the c-axis direction
Is sharp and thin, half width B₀₀₁Is also smaller. But
What (B₁₁₀/ B₀₀₁The value of) increases.

That is, the present inventors can provide not only good fluidity but also excellent flame retardancy even with the use of a relatively small amount of flame retardant. A series of studies were conducted in order to obtain a sealing material capable of effectively suppressing the deterioration of the property. As a result, the polyhedral metal hydroxide [component (C)] and the red phosphorus-based flame retardant [component (E)] are used in combination as the flame retardant, and the ion scavenger [component (D)] is used.
It has been found that the use of a metal hydroxide makes it possible to reduce the amount of the metal hydroxide [component (C)] having the above-mentioned polyhedral shape, thereby obtaining excellent fluidity. In addition, an impurity in the sealing material is the above-mentioned ion scavenger [(D)
The present invention has been found that a sealing material capable of obtaining a highly reliable semiconductor device by suppressing a decrease in moisture resistance due to the impurities and being obtained by the above-described impurities can be obtained.

When the content of the ion scavenger [component (D)] is set to a specific ratio, ionic substances can be effectively trapped and excellent moisture resistance can be obtained. It is preferable because dirt and the like hardly occur in the package.

Further, the above ion scavenger [component (D)]
It is preferable to use a hydrotalcite compound as the compound because it selectively and effectively captures anions among impurities and is a non-antimony-based compound.

[0018]

Next, embodiments of the present invention will be described in detail.

The epoxy resin composition for semiconductor encapsulation of the present invention comprises an epoxy resin (component A), a phenolic resin (component B), and a specific polyhedral metal hydroxide (component C).
, An ion scavenger (D component) and a red phosphorus-based flame retardant (E component), and are usually in the form of a powder or a tablet obtained by compressing the powder. Or
After the resin composition is melted and kneaded, it is formed into a granular sealing material formed into granules such as a substantially columnar shape, and further into a sheet-shaped sealing material.

The epoxy resin (component (A)) is not particularly limited, and various conventionally known epoxy resins can be used. For example, bisphenol A type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin and the like can be mentioned.

Among the above epoxy resins, it is preferable to use a biphenyl type epoxy resin. For example, a biphenyl type epoxy resin represented by the following general formula (2) is used.

[0022]

Embedded image

Of the alkyl groups having 1 to 5 carbon atoms represented by R _{1 to} R ₄ in the general formula (2), the alkyl groups include a methyl group, an ethyl group, n
- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, a linear or branched lower alkyl group such as a tert- butyl group are exemplified, particularly preferably a methyl group, the R ₁ ~ R ₄ may be the same or different. Among them, it is particularly preferable to use a biphenyl-type epoxy resin having a structure represented by the following formula (3) in which all of R _{1 to} R ₄ are methyl groups, from the viewpoint of low hygroscopicity and reactivity.

[0024]

Embedded image

The phenol resin (component B) used together with the epoxy resin (component A) acts as a curing agent for the epoxy resin, and is not particularly limited, and a conventionally known one can be used. Examples include phenol novolak, cresol novolak, bisphenol A type novolak, naphthol novolak, and phenol aralkyl resin. Especially, when a biphenyl type epoxy resin is used as the epoxy resin (component A), it is preferable to use a phenol aralkyl resin represented by the following general formula (4) as the phenol resin.

[0026]

Embedded image

The mixing ratio of the epoxy resin (component A) and the phenol resin (component B) is such that the hydroxyl group in the phenol resin is 0.7 to 1.3 equivalent per equivalent of epoxy group in the epoxy resin. It is preferable to set so that it becomes, and it is especially preferable to set so that it may become 0.9 to 1.1 equivalent.

The specific polyhedral metal hydroxide (component C) used together with the above components A and B is represented by the following general formula (1) and has a polyhedral crystal shape. .

[0029]

Embedded image

With respect to the metal hydroxide represented by the general formula (1), M in the formula (1) represents M
At least one selected from the group consisting of g, Ca, Sn, and Ti can be used.

Further, Q representing another metal atom in the metal hydroxide represented by the general formula (1) is M
At least one selected from the group consisting of n, Fe, Co, Ni, Cu and Zn is given.

Such a metal hydroxide having a polyhedral crystal shape can be formed in the thickness direction (c-axis direction) in both the vertical and horizontal directions by controlling various conditions in the production process of the metal hydroxide. It is possible to obtain a metal hydroxide having a desired polyhedral shape, such as a substantially dodecahedral, a substantially octahedral, or a substantially tetrahedral shape, having a large crystal growth.

The polyhedral metal hydroxide used in the present invention has, as one example, a polyhedral structure having an approximately octahedral crystal outer shape and an aspect ratio of about 1 to 8, preferably 1 to 8.
7, particularly preferably adjusted to 1 to 4. For example, in the case of M = Mg and Q = Zn in the formula (1), it can be manufactured as follows. That is, first, a zinc nitrate compound is added to an aqueous solution of magnesium hydroxide to prepare a partial metal hydroxide as a raw material. Next, this raw material is fired at a temperature in the range of 800 to 1500 ° C., more preferably in a range of 1000 to 1300 ° C., to produce a composite metal oxide. This composite metal oxide is represented by a composition of m (MgO) · n (ZnO), and further includes at least one selected from the group consisting of carboxylic acids, metal salts of carboxylic acids, inorganic acids, and metal salts of inorganic acids. By subjecting one of the composite metal oxides to a hydration reaction at a temperature of 40 ° C. or more with vigorous stirring in a system in an aqueous medium containing about 0.1 to 6 mol% of acetic acid with respect to the above composite metal oxide, Mg ₁ -x Zn _X (OH) ₂ (X is 0.01 to 0.5
(Positive number), the metal hydroxide having the polyhedral shape of the present invention can be produced.

In the above-mentioned production method, the raw materials include not only the partial metal hydroxide obtained by the above-mentioned method, but also, for example, a metal hydroxide obtained by a coprecipitation method, a mixture of magnesium hydroxide and Zn, and magnesium oxide. A mixture of Zn oxide, a mixture of magnesium carbonate and Zn carbonate, and the like can also be used. In addition, stirring during the hydration reaction,
Strong agitation is preferred for improving uniformity and dispersibility, for improving the contact efficiency with carboxylic acid, at least one selected from the group consisting of metal salts of carboxylic acids, inorganic acids and metal salts of inorganic acids, etc. It is even more preferable to use a high shearing agitation. Such stirring is preferably performed, for example, with a rotary blade type stirrer at a peripheral speed of the rotary blade of 5 m / s or more.

The carboxylic acid is not particularly limited, but preferably includes a monocarboxylic acid, an oxycarboxylic acid (oxyacid) and the like. Examples of the monocarboxylic acid include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, acrylic acid, crotonic acid, and the like. Examples of the oxycarboxylic acid (oxyacid) include glycolic acid, Lactic acid, hydroacrylic acid,
α-oxybutyric acid, glyceric acid, salicylic acid, benzoic acid, gallic acid and the like. The metal salt of the carboxylic acid is not particularly limited, but preferably includes magnesium acetate, zinc acetate and the like. The inorganic acid is not particularly limited, but preferably includes nitric acid, hydrochloric acid, and the like. The inorganic acid metal salt is not particularly limited, but preferably includes magnesium nitrate, zinc nitrate and the like.

A typical representative example of the metal hydroxide having the polyhedral shape is Mg _{1 -x} Ni _x (OH)
₂ [0.01 <X <0.5], Mg _1-X Zn _X (OH)
₂ [0.01 <X <0.5] and the like. Examples of commercially available metal hydroxides include, for example, Echomag manufactured by Tateho Chemical Industries.

The specific surface area of the polyhedral metal hydroxide as the component (C) is preferably in the range of 2.0 to 4.0 m ² / g. The specific surface area of the component (C) is measured by a BET adsorption method.

The aspect ratio of the metal hydroxide having the polyhedral shape (component C) is usually 1 to 8, preferably 1 to 7, and particularly preferably 1 to 4. Here, the aspect ratio is expressed by the ratio of the major axis to the minor axis of the metal hydroxide. That is, when the aspect ratio exceeds 8, the effect of lowering the viscosity when the resin composition containing the metal hydroxide is melted becomes poor. And when used as a component of the epoxy resin composition for semiconductor encapsulation of the present invention, the aspect ratio is generally 1 to
Four are used.

In the present invention, a conventional thin-plate-shaped metal hydroxide can be used together with the polyhedral metal hydroxide as the component (C). And
From the viewpoint of lowering the viscosity and expressing the effect of fluidity when the epoxy resin composition for semiconductor encapsulation of the present invention is melted,
The ratio of the polyhedral metal hydroxide to the total metal hydroxide used (including the conventional thin plate shape) is 3
It is preferable to set in the range of 0 to 100% by weight. That is, the ratio of the polyhedral metal hydroxide is 30%.
If the amount is less than% by weight, the effect of lowering the viscosity of the resin composition and the effect of improving the fluidity become poor.

The polyhydric metal hydroxide (C)
The content of the metal hydroxide containing the component (1) is preferably set in the range of 1 to 30% by weight, particularly 3 to 25% by weight of the whole resin composition. That is, the metal hydroxide is 1
If the amount is less than 30% by weight, it is difficult to obtain a sufficient flame-retardant effect, and if the amount is more than 30% by weight, the fluidity tends to decrease, and the flow of the wire tends to be poor.

Examples of the ion scavenger (component D) used together with the components A to C include bismuth hydroxide,
Examples include hydrotalcite compounds represented by DHT-4A manufactured by Kyowa Chemical Company, antimony pentoxide, and the like. These may be used alone or in combination of two or more. Among them, bismuth hydroxide and hydrotalcite compounds, particularly hydrotalcite compounds, are preferably used from the viewpoint of selectively trapping anions and non-antimony. Further, as the ion scavenger (D component), it is preferable to use an ion scavenger having an average particle diameter in the range of 0.1 to 50 μm by a laser particle size analyzer from the viewpoint of fluidity.

The content of the ion scavenger (component D) is 0.01 to 10% in the epoxy resin composition for semiconductor encapsulation.
It is preferably set in the range of wt%, particularly preferably 0.05 to 2.0 wt%. That is, 0.01
If the amount is too small, such as less than 10% by weight, ionic substances as impurities are not effectively trapped. As a result, it becomes difficult to obtain excellent moisture resistance. This is because there is a tendency for dirt to occur.

The red phosphorus flame retardant (component E) used together with the above components A to D includes those composed of red phosphorus alone.
This red phosphorus alone is liable to be oxidized, and has a difficulty in handling due to its instability. For this reason, those obtained by coating the surface of red phosphorus in advance with various organic and inorganic substances, for example, at least one of a metal hydroxide and a phenol resin are preferably used. Examples of the metal hydroxide serving as the coating material include magnesium hydroxide and aluminum hydroxide. In addition, the phenol resin is not particularly limited, and includes various conventionally known phenol resins. The content of red phosphorus in the thus coated red phosphorus flame retardant is preferably 45 to 95% by weight, particularly preferably 70 to 95% by weight. That is, if the content of red phosphorus is less than 45% by weight, it is difficult to obtain the desired flame retardancy unless the red phosphorus-based flame retardant itself is added in a large amount. This is because there is a tendency to decrease and cause problems in stability and purity.

Further, it is preferable to use the red phosphorus-based flame retardant having an average particle diameter of 5 to 70 μm, more preferably 10 to 45 μm by a laser type particle size analyzer.
μm. That is, when the average particle size of the red phosphorus-based flame retardant exceeds 70 μm, the dispersibility of the red phosphorus-based flame retardant tends to decrease, and when the average particle diameter is less than 5 μm, the flowability tends to decrease. It is.

The content of the red phosphorus-based flame retardant (component E) is 0.0% of the entire epoxy resin composition for semiconductor encapsulation.
It is preferably set in the range of 1 to 2.0% by weight, and particularly preferably 0.03 to 1.5% by weight. That is, the content of the red phosphorus-based flame retardant (component E) is 0.01% by weight.
If the amount is too small, the addition amount of the metal hydroxide (component C) tends to increase relatively to lower the fluidity in order to obtain the intended flame retardancy. If the content is more than 2.0% by weight, the amount of impurities is increased, and the reliability of moisture resistance is lowered, and the possibility of increasing environmental pollution tends to be observed.

In general, an inorganic filler is used together with the above components A to E. The inorganic filler is not particularly limited, such as a crushed shape, a crushed shape, and a spherical shape, and includes various conventionally known fillers. For example, quartz glass powder,
Talc, silica powder such as fused silica powder and crystalline silica powder, alumina, silicon nitride, aluminum nitride, silicon carbide and the like. Preferably, fused silica powder, especially spherical fused silica powder, is used from the viewpoint of fluidity. These may be used alone or in combination of two or more. The inorganic filler preferably has an average particle size of 10 to 70 μm, more preferably 10 to 50 μm, measured by a laser type particle size analyzer. That is, when the average particle size of the inorganic filler is within the above range, good fluidity of the resin composition can be obtained.

The content of the inorganic filler is preferably set so as to be 60 to 95% by weight of the whole epoxy resin composition for semiconductor encapsulation.

The epoxy resin composition for semiconductor encapsulation according to the present invention contains a curing accelerator, a pigment, a mold release agent, a surface treatment agent, a flexibility imparting agent, in addition to the above-mentioned components A to E and an inorganic filler. An agent, an adhesion-imparting agent and the like can be appropriately added as needed.

The curing accelerator is not particularly limited as long as it promotes the reaction between an epoxy group and a hydroxyl group. For example, 1,8-diazabicyclo (5,
(4,0) diazabicycloalkene compounds such as undecene-7, tertiary amines such as triethylenediamine,
Imidazoles such as methylimidazole; and phosphorus-based compounds such as triphenylphosphine. These compounds are used alone or in combination of two or more.

Examples of the pigment include carbon black and titanium oxide. Further, as the release agent,
Carnauba wax, polyethylene wax, paraffin, fatty acid ester, fatty acid salt and the like can be mentioned.

Further, examples of the surface treatment agent include coupling agents such as a silane coupling agent [for example, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like]. Examples of the flexibility imparting agent include various silicone compounds and butadiene-acrylonitrile rubber.

In the epoxy resin composition for encapsulating a semiconductor according to the present invention, an organic flame retardant may be used in addition to the above components. By using the organic flame retardant, the metal hydroxide having the polyhedral shape (C component)
Can be reduced in the amount of the metal hydroxide and the red phosphorus-based flame retardant containing the same. As the organic flame retardant,
Examples thereof include a nitrogen-containing organic compound, a phosphorus-containing organic compound, and a phosphazene-based compound, and a nitrogen-containing organic compound is particularly preferably used.

Examples of the nitrogen-containing organic compound include:
Compounds having a heterocyclic skeleton such as a melamine derivative, a cyanurate derivative, and an isocyanurate derivative are exemplified.
These organic flame retardants are used alone or in combination of two or more.

The organic flame retardant may be blended after being mechanically mixed with the metal hydroxide (component C) and the red phosphorus flame retardant (component E) in advance, or the organic flame retardant may be mixed with a solvent. May be used after adding the above-mentioned metal hydroxide (component C) and red phosphorus-based flame retardant (component E) thereto, removing the solvent, and performing a surface treatment.

The content of the organic flame retardant is determined by the amount of the metal hydroxide (total amount of the polyhedral metal hydroxide and the conventional thin flat metal hydroxide optionally used) and red 0.5 to 20 of the total amount of the phosphorus-based flame retardant (component E)
It is preferable to set the weight% in the range. Particularly preferably, it is 1.0 to 16% by weight.

In the epoxy resin composition for semiconductor encapsulation according to the present invention, suitable combinations of the components including the above-mentioned components A to E are as follows. That is,
Among the epoxy resins (component A), biphenyl-based epoxy resins are preferred from the viewpoint of good fluidity,
As the phenol resin (component B), a phenol aralkyl resin is preferred from the viewpoint of fluidity. And bismuth hydroxide as an ion scavenger (D component),
Hydrotalcite compounds are preferred, and a red phosphorus-based flame retardant (component E) whose red phosphorus surface is coated and coated with a metal hydroxide and a phenol resin is preferably used. Further, as an inorganic filler, fused silica powder is used. It is preferable to use Furthermore, in addition to each of these components,
When a metal hydroxide as described above is used, it is preferable to use waxes since the releasability tends to decrease.

The epoxy resin composition for semiconductor encapsulation according to the present invention can be produced, for example, as follows. That is, epoxy resin (A component), phenol resin (B component), specific polyhedral metal hydroxide (C component), ion scavenger (D component), red phosphorus flame retardant (E component), and inorganic filler The ingredients and, if necessary, other additives are blended in a predetermined ratio and mixed well with a mixer or the like.
Next, the mixture is melted and kneaded in a heated state using a kneading machine such as a mixing roll machine or a kneader, and the mixture is cooled to room temperature. Then, the desired epoxy resin composition for semiconductor encapsulation can be produced by a series of steps of pulverization by known means and tableting as necessary.

Alternatively, after a mixture of the epoxy resin composition for semiconductor encapsulation is introduced into a kneader and kneaded in a molten state, the mixture is continuously formed into substantially columnar granules or pellets. The epoxy resin composition for semiconductor encapsulation can also be produced by the steps.

Further, the mixture of the epoxy resin composition for semiconductor encapsulation is received on a pallet, and after cooling, press rolling, roll rolling, or coating with a mixture of solvents to form a sheet is performed. According to the method, a sheet-like epoxy resin composition for semiconductor encapsulation can be produced.

The method for encapsulating a semiconductor element using the epoxy resin composition for encapsulating a semiconductor (powder, tablet, granule, etc.) obtained as described above is not particularly limited, and ordinary transfer methods can be used. It can be performed by a known molding method such as molding.

Using the sheet-like epoxy resin composition for semiconductor encapsulation, a semiconductor device can be manufactured by flip chip mounting, for example, as follows. That is, the sheet-shaped semiconductor sealing epoxy resin composition is disposed on the electrode surface side of the semiconductor element provided with the bonding bumps, or on the bump bonding part side of the circuit board, and the semiconductor element and the circuit board are bonded together. A semiconductor device can be manufactured by flip-chip mounting by performing bump bonding and bonding and sealing the both by resin sealing.

Next, examples will be described together with comparative examples.

First, the following materials were prepared.

[Epoxy resin A1] 4,4'-bis (2,3-epoxypropoxy) -3,
3 ', 5,5'-tetramethylbiphenyl

[Epoxy resin A2] Cresol novolak type epoxy resin (epoxy equivalent 1
98, softening point 75 ° C)

[Phenol Resin B1] A phenol aralkyl resin represented by the above formula (4) (hydroxyl equivalent 174, softening point 70 ° C.)

[Phenol resin B2] Phenol novolak resin (hydroxyl equivalent 105, softening point 80 ° C)

[Metal hydroxide] Polyhedral metal hydroxide Composition: Mg _0.8 Zn _0.2 (OH) ₂ Average particle size: 1.7 μm Particle size distribution: 14% by weight less than 1.3 μm, particle size 1 .3
61% by weight or more and less than 2.0μm, particle size 2.0μm to 25% by weight

[Red Phosphorus Flame Retardant] A red phosphorus powder surface coated with magnesium hydroxide and a phenol resin (red phosphorus content: 93% by weight, average particle diameter: 30 μm: Nova Excel, manufactured by Rin Kagaku Kogyo KK)

[Ion scavenger] Hydrotalcite compound: Mg_4.3Al_Two(OH)
_12.6CO_Three・ 3.5H _TwoO (average particle size 2 μm) (DHT
-4A, manufactured by Kyowa Chemical Co., Ltd.)

[Release Agent] Polyethylene Wax

[Curing accelerator] Triphenylphosphine

[Inorganic filler] Fused silica powder (spherical, average particle size 25 μm, specific surface area 1.4 m ² / g)

[0074]

Examples 1 to 8 and Comparative Examples 1 to 6
The components shown in Table 2 were blended in the proportions shown in the table, and were melt-kneaded for 3 minutes with a mixing roll machine (temperature 100 ° C.)
After cooling and solidifying, the mixture was pulverized to obtain a desired powdery epoxy resin composition.

[0075]

[Table 1]

[0076]

[Table 2]

The epoxy resin compositions thus obtained in Examples and Comparative Examples were evaluated for fluidity (flow tester viscosity, gel time). Further, the cured product of the epoxy resin composition is pulverized into a powder,
5 g passed through a 0 μm mesh and the outside was metal (SU
In S), 50 ml of ion-exchanged water was put into a container having Teflon (registered trademark) inside, and extraction was performed at 160 ° C for 20 hours. The amount of impurities (Na ⁺ ,
Cl ⁻ , HPO ₃ ²⁻ , and PO ₄ ³⁻ ) were measured by ion chromatography. In addition, EC
(Electrical conductivity) is measured by an electric conductivity meter (ELECTRICAL CONDUCTIV
ITY). The pH value was also measured with a pH meter. In addition, dirt on the package surface during package molding using the epoxy resin composition was confirmed and evaluated.

A tablet was formed from each of the above epoxy resin compositions under molding conditions of 175 ° C. × 6.867M.
A test piece for flame retardancy was formed at Pa × 120 seconds. on the other hand,
LQFP-114 (size: 20) with TOWA automatic molding machine
(mm × 20 mm × 1.4 mm thickness). Using these test pieces for flame retardancy and the package, the flame retardancy and humidity resistance reliability were measured and evaluated. The results are shown in Tables 3 and 4 below.

[Flow Tester Viscosity] Each of the above epoxy resin compositions was precisely weighed in an amount of 2 g and formed into a tablet. Then, put this in the pot of the Koka type flow tester,
The measurement was performed with a load of 0 kg. The epoxy resin composition melted at 175 ° C.
(mm × 10 mm), the melt viscosity of the sample was determined from the moving speed of the piston when extruded.

[Gel Time] A sample (200 to 500 mg) was placed on a hot plate at a specified temperature (175 ° C.), stretched thinly on the hot plate with stirring, and from when the sample melted on the hot plate until it hardened. The time was read and defined as the gel time (gel time).

[Flame retardancy] Flame retardancy was evaluated according to the method of UL94 V-0 standard. In addition, pass means 94-V0 pass.

[Moisture Resistance Reliability] A pressure cooker bias test (PCBT test) was performed using the semiconductor device thus manufactured (conditions: 130 ° C./85%).
RH, 30V bias). Then, the time when 50% of the semiconductor devices used in the evaluation were in the failure mode was measured. In the failure mode, leakage failure and open failure were measured.

[Amount of Impurities in Cured Product] (Extraction of Impurities) The cured product was pulverized into a powder with a vibrating mill, and fine powder was obtained through a net having openings of 150 μm. 5 g of this fine powder and 50 ml of ion-exchanged water were charged into an extraction container (a container having metal (SUS) on the outside and Teflon on the inside) and sealed. This was left in a dryer at 160 ° C. for 20 hours, and then returned to room temperature to obtain an extract.

(Impurity) Analysis was performed using ion chromatography, and a calibration curve was prepared using impurity ions to be measured in advance using a standard sample. Then, predetermined ions were quantified by the same ion chromatography.

[EC value and pH value of cured product] Using an extract for measuring the amount of impurities in the cured product, pH was measured with a pH meter.
The values and the EC (electric conductivity) were measured with an electric conductivity meter.

[Package surface contamination] A QFP-80 pin (80-pin four-way flat package: 14 mm × 20 mm × thickness 2.7 m) was prepared using the above-mentioned epoxy resin composition by an automatic molding machine (multiplunger system).
m) was continuously visualized at 175 ° C. × 60 seconds for 300 shots.

[0087]

[Table 3]

[0088]

[Table 4]

From the results shown in Tables 3 and 4, the products of Examples exhibited excellent flame retardancy, and furthermore, the content of various ions as impurities was small, and good results were obtained also in moisture resistance. Also, regarding the fluidity, it can be seen that both the viscosity of the flow tester and the gel time are good. On the other hand, the product of Comparative Example contained no flame retardancy because the flame retardant was blended, but was found to be inferior in moisture resistance.

Further, in Example 1, the epoxy resin component was a biphenyl type epoxy resin in which all of R _{1 to} R ₄ in the above formula (2) were hydrogen, and the epoxy resin component in the above formula (2)
_The mixture was replaced with a mixed type epoxy resin in which a biphenyl type epoxy resin in which all of _{1 to} R ₄ are methyl groups was blended at a weight ratio of 1: 1. Otherwise, the same blending ratio as in Example 1 was set to produce an epoxy resin composition. Using this epoxy resin composition, the same measurements and evaluations as above were performed, and as a result, almost the same good results as in the above example were obtained.

[0091]

As described above, the present invention provides a polyhedral metal hydroxide (C component) represented by the general formula (1).
And an epoxy resin composition for semiconductor encapsulation containing an ion scavenger (D component) and a red phosphorus-based flame retardant (E component). As described above, since the polyhedral metal hydroxide (component C) is used, the resin composition has excellent flame retardancy and fluidity, and contains an ion scavenger (component D), so that impurities in the resin composition are reduced. It is trapped, and as a result, one having excellent moisture resistance reliability can be obtained. Further, since a red phosphorus-based flame retardant is used, the amount of the metal hydroxide (component C) to be added can be reduced in order to obtain the desired flame retardancy, so that better fluidity can be obtained. Becomes Therefore, by sealing a semiconductor element using the epoxy resin composition for semiconductor sealing, a highly reliable semiconductor device having excellent moisture resistance reliability can be obtained.

By setting the content of the ion scavenger (component D) to a specific ratio, an ion substance can be effectively trapped and excellent moisture resistance can be obtained. This is preferable because dirt and the like hardly occur.

Furthermore, by using a hydrotalcite compound as the ion scavenger (component D), anions can be selectively and effectively trapped among impurities,
Moreover, it is preferable because it is non-antimony-based.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph (magnification: 5) showing an example of the crystal shape of a polyhedral metal hydroxide used in the present invention.
0000 times).

FIG. 2 is a perspective view showing a hexagonal plate-like shape which is one of the crystal shapes of a conventional metal hydroxide.

FIGS. 3A and 3B are explanatory views showing the outer shape of a conventional metal hydroxide, wherein FIG. 3A is a plan view and FIG. 3B is a side view.

FIG. 4 is an explanatory view showing an example of the outer shape of the metal hydroxide of the present invention, wherein (a) is a plan view and (b) is a side view.

FIG. 5 is an explanatory view showing another example of the outer shape of the metal hydroxide of the present invention, wherein (a) is a plan view and (b) is a side view.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/29 H01L 23/30 R 23/31 (72) Inventor Masahiro Hata 1-chome Shimohozumi, Ibaraki-shi, Osaka No. 1-2 F-term in Nitto Denko Corporation (reference) 4J002 CC03X CC05X CC06X CC27X CD00W CD05W CD06W DA058 DE046 DE096 DE106 DE116 DE136 DE287 FA116 FD010 FD090 FD14X FD150 FD207 GJ02 4J036 AD07 AD08 AF06 AF07 FA01 FA03 FA03 FA03 FA03 FA03 EA02 EB03 EB04 EB06 EB07 EB08 EB09 EB12 EB18 EC01 EC20

Claims (4)

[Claims] 1. An epoxy resin composition for semiconductor encapsulation, comprising the following components (A) to (E). (A) Epoxy resin. (B) a phenolic resin. (C) A polyhedral metal hydroxide represented by the following general formula (1). Embedded image (D) an ion scavenger. (E) Red phosphorus-based flame retardant. 2. The content of the ion scavenger as the component (D) is 0.1 to 10% by weight of the whole epoxy resin composition.
The epoxy resin composition for semiconductor encapsulation according to claim 1, which is: 3. The ion scavenger as the component (D),
3. The epoxy resin composition for semiconductor encapsulation according to claim 1, which is a hydrotalcite compound. 4. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.