JP2001316453A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

[PROBLEMS] Epoxy resin for semiconductor encapsulation that does not contain halogen and antimony, is excellent in flame retardancy, fast curing, fluidity, moisture resistance, and high temperature storage characteristics, and is suitable for insertion mounting and surface mounting. Obtaining the composition. SOLUTION: (A) an epoxy resin, (B) a phenolic resin, (C) a compound (Y) having tetra-substituted phosphonium (X) and two or more phenolic hydroxyl groups in one molecule, and a phenolic hydroxyl group in one molecule Is a molecular association with a conjugate base of a compound (Y) having two or more phenolic hydroxyl groups in the compound (Y) having two or more phenolic hydroxyl groups in one molecule. An epoxy resin composition comprising a curing accelerator comprising a phenoxide type compound, (D) red phosphorus or a red phosphorus-based flame retardant, and (E) an inorganic filler as essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

The present invention relates to an epoxy resin composition for semiconductor encapsulation having excellent flame retardancy, and a semiconductor device having a semiconductor element encapsulated using the epoxy resin composition.

[0002]

2. Description of the Related Art Conventionally, diodes, transistors, and ICs
Semiconductor elements such as chips are sealed with an epoxy resin composition to protect them from mechanical and chemical actions. The epoxy resin composition contains a halogen-based flame retardant as a flame retardant, or a combination of a halogen-based flame retardant and antimony trioxide, and an inorganic filler such as fused silica or crystalline silica as a filler. . However, from the viewpoint of environmental hygiene, a demand for a flame-retardant epoxy resin composition that does not use a halogen compound or an antimony compound is increasing. In addition, when a semiconductor device sealed with an epoxy resin composition containing a halogen compound and an antimony compound is stored at a high temperature, a thermally decomposed halide is released from these flame retardant components, and the junction of the semiconductor element is removed. It is known that they corrode and impair the reliability of semiconductor devices. As described above, the junction (bonding pad) of the semiconductor element after storing the semiconductor device at a high temperature (for example, 185 ° C.).
In order to improve the corrosion resistance, that is, the high-temperature storage characteristics, there is an increasing demand for an epoxy resin composition that does not use a halogen compound or an antimony compound. To meet these demands, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, boron compounds, etc. have been studied. Has not been reached. or,
A small amount of red phosphorus-based flame retardant is effective for making epoxy resin compositions flame-retardant, but red phosphorus reacts with a small amount of moisture to generate phosphate ions and phosphite ions, so that it has high moisture resistance. It is difficult to use an epoxy resin composition for semiconductor encapsulation, which has extremely severe requirements. For this reason, red phosphorus particles are coated with thermosetting resins such as aluminum hydroxide, metal oxides, inorganic compounds, and phenol resins to stabilize red phosphorus, but semiconductors that have extremely strict requirements for moisture resistance The epoxy resin composition for sealing was not satisfactory. In order to solve this problem, Japanese Patent Application Laid-Open No. 10-152599 proposes improving reliability by using fine and stable red phosphorus-based flame retardants to improve dispersibility. However, in recent years, multi-molding has increased in terms of productivity,
The molding cycle is becoming shorter, and the epoxy resin composition using a red phosphorus-based flame retardant has a problem that curability is reduced and the molding cycle cannot be shortened properly. Since the tendency of the curability to decrease becomes remarkable especially when the specific surface area of the red phosphorus-based flame retardant is increased, blending the red phosphorus-based fine particles is effective in improving the moisture resistance. This results in a decrease. Means for improving the curability include a method of increasing the amount of a curing accelerator added. However, problems such as poor filling and wire breakage occur due to a decrease in fluidity (increase in viscosity).

[0003]

SUMMARY OF THE INVENTION The present invention provides a flame-retardant, fast-curing, fluidity-free, halogen-free and antimony-free,
An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation excellent in moisture resistance and high-temperature storage characteristics, and a semiconductor device in which a semiconductor element is encapsulated using the same.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to improve the flame retardancy, rapid curing property, fluidity and moisture resistance. As a result, even if red phosphorus or a red phosphorus-based flame retardant is blended. The present inventors have found that an epoxy resin composition using a specific compound as a curing accelerator exhibits extremely excellent properties, and have completed the present invention based on this finding. That is, the present invention relates to [1] (A) an epoxy resin, (B) a phenol resin, (C) a tetra-substituted phosphonium (X), a compound (Y) having two or more phenolic hydroxyl groups in one molecule, and a compound (Y) in one molecule. Is a molecular association with a conjugate base of a compound (Y) having two or more phenolic hydroxyl groups, wherein the conjugate base is one compound from the compound (Y) having two or more phenolic hydroxyl groups in one molecule. An epoxy resin composition comprising, as essential components, a curing accelerator comprising a phenoxide-type compound from which hydrogen has been removed, (D) red phosphorus or a red phosphorus-based flame retardant, and (E) an inorganic filler. Compounds (Y) having two or more phenolic hydroxyl groups in one molecule are dihydroxybenzenes, trihydroxybenzenes, bisphenols, biphenols, dihydroxynaphthalenes, The epoxy resin composition according to item [1], wherein the epoxy resin composition is at least one member selected from the group consisting of a lan novolak resin and a phenol aralkyl resin, and [3] the molecular association is a tetra-substituted phosphonium / tetra-substituted borate (Z); Compound (Y) having two or more phenolic hydroxyl groups in the molecule
Is reacted at a high temperature, and then thermally reacted in a solvent having a boiling point of 60 ° C. or higher, the epoxy resin composition according to [1] or [2], The union is obtained by reacting a compound (Y) having two or more phenolic hydroxyl groups in one molecule, an inorganic base or an organic base, and a tetra-substituted phosphonium halide [1] to [3]. The epoxy resin composition according to any one of [1] to [4], wherein the tetra-substituted phosphonium (X) is tetraphenylphosphonium, [6] ] The epoxy resin composition according to any one of [1] to [5], wherein the epoxy resin (A) is a crystalline epoxy resin having a melting point of 50 to 150 ° C, [7] a crystal having a melting point of 50 to 150 ° C. Epoxy resin has the general formula (1) And 1 selected from formula (2)
The epoxy resin composition according to item [6], which is at least one kind,

Embedded image (Wherein, R ¹ is a group or an atom selected from a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and may be the same or different from each other. Good.)

[0005]

Embedded image (Wherein, R ² is a group or atom selected from a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and may be the same or different. Good.)

[8] The crystalline epoxy resin having a melting point of 50 to 150 ° C. is a mixture of a stilbene type epoxy resin represented by the general formula (3) and a stilbene type epoxy resin represented by the general formula (4). 6] The epoxy resin composition according to the above,

Embedded image (Wherein, R ^{3 to} R ¹⁰ each independently represent a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, or a group or atom selected from halogen. However, carbon-carbon The two aryl groups attached to the double bond are different from each other.)

[0007]

Embedded image (Wherein, R ^{11 to} R ¹⁴ each independently represent a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, and a group or atom selected from halogen. However, carbon-carbon (The two aryl groups bonded to the double bond are the same as each other.) [9] The phenol resin (B) according to any one of the items [1] to [8], wherein the phenol resin (B) is a phenol aralkyl resin. The epoxy resin composition according to any one of [1] to [9], wherein the red phosphorus-based flame retardant has an average particle diameter of 2 to 8 μm and a maximum particle diameter of 20 μm or less, [10] 11] The epoxy resin composition according to any one of [1] to [10], wherein the red phosphorus-based flame retardant is obtained by coating the surface of red phosphorus with an inorganic compound and / or a curable resin. After the red phosphorus-based flame retardant coats the surface of the red phosphorus with an inorganic compound, The epoxy resin composition according to any one of [1] to [11], wherein the surface is coated with a curable resin, wherein the inorganic compound is a metal hydroxide or a metal oxide. The epoxy resin composition according to [11] or [12], wherein the metal hydroxide is a hydroxide of aluminum, magnesium, or zinc;
The epoxy resin composition according to [13], wherein the metal oxide is an oxide of aluminum, magnesium, or zinc,
[15] The curable resin is, first [11] - [14] The epoxy resin composition according to any one of Items a phenolic resin or epoxy resin, in [16] total epoxy resin composition, BiO _X (OH ) _Y (NO ₃ ) _Z [where X = 0.9 to
1.1, Y = 0.6-0.8, Z = 0.2-0.4],
And / or Mg _4.3 Al ₂ (OH) _12.6 CO ₃ .3.5H ₂
[1] containing 0.2 to 2% by weight of an ion scavenger which is O
-The epoxy resin composition according to any one of [15],
[17] A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition according to any one of [1] to [16].

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention is:
There is no limitation as long as it has two or more epoxy groups in one molecule. For example, bisphenol A epoxy resin, bisphenol F epoxy resin, brominated bisphenol epoxy resin, biphenyl epoxy resin, stilbene epoxy resin , Phenol novolak type epoxy resin, cresol novolak type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin,
Glycidylamine type epoxy resins, naphthalene type epoxy resins, glycidyl ether compounds of resins synthesized by condensation of carbonyl compounds with naphthol, 4,4 ′
-Bis (1,2-epoxyethyl) diphenyl ether, 4,4′-bis (1,2-epoxyethyl) biphenyl, a glycidyl ether compound of a phenol resin obtained by reacting dicyclopentadiene with a phenol,
Furthermore, glycidyl ether compounds such as mononuclear resorcinol and catechol can be exemplified, and these may be used alone or in combination of two or more. Among these epoxy resins, a crystalline epoxy resin having a melting point of 50 to 150 ° C. is preferable. Such a crystalline epoxy resin has a rigid structure such as a biphenyl skeleton, a bisphenol skeleton, or a stilbene skeleton in its main chain, and has a relatively low molecular weight.
It shows crystallinity. The crystalline epoxy resin is a solid that crystallizes at room temperature, but rapidly melts and changes to a low-viscosity liquid in a temperature range higher than the melting point.
The melting point of the crystalline epoxy resin indicates the temperature at the top of the endothermic peak of crystal melting when the temperature is raised from room temperature at a temperature rising rate of 5 ° C./min using a differential scanning calorimeter. As the crystalline epoxy resin satisfying these conditions, in particular, one or more selected from the general formulas (1) and (2) or the stilbene type epoxy resin represented by the general formula (3) and the general formula (4) A mixture with the stilbene type epoxy resin represented by the formula (1) is preferred.

[0009] The substituent R ¹ of the biphenyl type epoxy resin represented by the general formula (1) and the substituent R ² of the bisphenol type epoxy resin represented by the general formula (2) are a hydrogen atom and a carbon number of 1 to 1. 6, a group or atom selected from a chain or cyclic alkyl group, a phenyl group, and a halogen, which may be the same or different, such as a methyl group, an ethyl group, a propyl group, and a butyl group. Groups, a cyclohexyl group, a phenyl group, a chlorine atom, a bromine atom and the like, and a methyl group is particularly preferred.

The substituents R ^{3 to} R ¹⁴ of the stilbene type epoxy resin represented by the general formulas (3) and (4) are a hydrogen atom, a linear or cyclic alkyl group having 1 to 6 carbon atoms,
And a group or an atom selected from halogen and may be the same or different from each other. For example, a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group (each Isomers), a cyclohexyl group, a chlorine atom, a bromine atom and the like, and particularly, a methyl group, an ethyl group, a propyl group, or a butyl group is preferable in view of the low melt viscosity of the epoxy resin. As these stilbene type epoxy resins, a mixture of the stilbene type epoxy resin of the general formula (3) and the stilbene type epoxy resin of the general formula (4) is preferable, and the stilbene type epoxy resin of the general formula (3) and the general formula (3) The stilbene-type epoxy resins of (4) each have various structures depending on the type of the substituent and the like. Each of the stilbene-type epoxy resins of general formulas (3) and (4) has one type of structure. Even those
A mixture of two or more structures may be used. Mixing of the stilbene-type epoxy resin of the general formula (3) and the stilbene-type epoxy resin of the general formula (4) only needs to lower the melting point by mixing both compounds, and the mixing method is not particularly limited. For example, there is a method of mixing stilbene-type phenols, which are raw materials of the stilbene-type epoxy resin, before glycidyl etherification, or a method of melting and mixing both stilbene-type epoxy resins. Adjust so as to be 50 to 150 ° C. As the stilbene type epoxy resin represented by the general formula (3), 5-tert-butyl-4,4′-dihydroxy- is preferred in view of availability, performance, and raw material price.
2,3 ', 5'-trimethylstilbene, 3-tert-butyl-4,4'-dihydroxy-3', 5,5'-
Glycidyl etherified trimethylstilbene is particularly preferred. As the stilbene type epoxy resin represented by the general formula (4), 4,4′-dihydroxy-3,3 ′, 5,5′-tetramethylstilbene,
Glycidyl ether of 4,4'-dihydroxy-3,3'-ditert-butyl-6,6'-dimethylstilbene, 4,4'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethylstilbene Are particularly preferred.

The phenolic resin (B) used in the present invention comprises:
It functions as a curing agent for the epoxy resin (A). There is no limitation as long as it has two or more phenolic hydroxyl groups in one molecule. Specifically, a phenol resin or a phenol aralkyl resin having a phenylene or biphenylene skeleton, which is a co-condensation reaction product of a phenol and an aldehyde or a ketone, such as a phenol resin or a bisphenol, or a phenol and a dimethoxy para-xylene. Included are mononuclear resorcinols, catechols, etc., which can be used as long as they cause a curing reaction.However, since the definition of "phenol" is generally a compound in which the hydrogen atom bonded to the aromatic ring has been replaced with a hydroxyl group, such as naphthol, etc. A co-condensation reaction product of a hydroxyl group-containing compound derived from a condensed polycyclic aromatic compound and a carbonyl compound is also included. Among these phenolic resins, the water absorption of the cured product is small because the number of hydroxyl groups in the molecule is small, and the reactivity in the curing reaction is good because the molecule has an appropriate flexibility, and the viscosity can be reduced. For this reason, phenol aralkyl resins are particularly preferred. In the present invention, the ratio of the total epoxy resin to the total phenol resin acting as a curing agent is such that the phenolic hydroxyl group is 0.5 to 2 mol, preferably 0.8 mol, per 1 mol of the epoxy group.
By adjusting the molar ratio to about 1.2, the curability, the heat resistance of the cured product, the electrical characteristics, and the like are further improved.

The molecular accelerator as the curing accelerator (C) used in the present invention comprises a tetrasubstituted phosphonium (X), a compound (Y) having two or more phenolic hydroxyl groups in one molecule, and a phenolic compound in one molecule. A molecular association with a conjugate base of a compound (Y) having two or more hydroxyl groups, wherein the conjugate base removes one hydrogen from the compound (Y) having two or more phenolic hydroxyl groups in one molecule. Phenoxide type compound. The substituent of the tetra-substituted phosphonium (X), which is one of the components of the molecular assembly of the present invention, is not limited at all, and the substituents may be the same or different. For example, a tetra-substituted phosphonium ion having a substituted or unsubstituted aryl or alkyl group as a substituent is preferable because it is stable against heat and hydrolysis. Specifically, tetraphenylphosphonium, tetratolylphosphonium, tetraethylphenylphosphonium, tetramethoxyphenylphosphonium, tetranaphthylphosphonium, tetrabenzylphosphonium, ethyltriphenylphosphonium, n-butyltriphenylphosphonium, 2-hydroxyethyltriphenylphosphonium, Examples include trimethylphenylphosphonium, methyldiethylphenylphosphonium, methyldiallylphenylphosphonium, tetra-n-butylphosphonium and the like.

[0013] The constituent component of the molecular assembly of the present invention, 1
As the compound (Y) having two or more phenolic hydroxyl groups in the molecule, for example, bis (4-hydroxy-3,
5-dimethylphenyl) methane (commonly known as tetramethylbisphenol F), 4,4′-sulfonyldiphenol,
4,4′-isopropylidene diphenol (commonly known as bisphenol A), bis (4-hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, and among them Bis (4-hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, and a mixture of three kinds of (2-hydroxyphenyl) (4-hydroxyphenyl) methane (for example, Bisphenol F manufactured by Honshu Chemical Industry Co., Ltd.) Bisphenols such as -D), 1,2-
Benzenediol, 1,3-benzenediol, 1,4
Dihydroxybenzenes such as benzenediol, 1,
Trihydroxybenzenes such as 2,4-benzenetriol, various isomers of dihydroxynaphthalenes such as 1,6-dihydroxynaphthalene, various isomers of biphenols such as 2,2′-biphenol and 4,4′-biphenol And the like. Further, the conjugate base as another component is a phenoxide-type compound obtained by removing one hydrogen from the compound (Y).

Although the molecular aggregate of the present invention has a phosphonium-phenoxide type salt in its structure as described above, it is different from the conventional phosphonium-organic acid anion salt type compound in the structure of the present invention. In the aggregate, the higher-order structure due to the hydrogen bond surrounds the ionic bond. In the salt of the prior art, the reactivity is controlled only by the strength of the ionic bond, whereas in the molecular aggregate of the present invention, the enclosing by the higher-order structure of the anion protects the active site at normal temperature, while In the molding stage, the active sites are exposed due to the collapse of the higher-order structure, and so-called latency, which expresses reactivity, is imparted.

The method for producing the molecular aggregate of the present invention is not limited at all, but two typical methods can be mentioned. 1
The third is that a tetra-substituted phosphonium / tetra-substituted borate (Z) and a compound (Y) having two or more phenolic hydroxyl groups in one molecule are reacted at a high temperature, and then reacted at a boiling point of 60 ° C. or more. This is a method of performing a thermal reaction in a solvent. 2
The third is a method of reacting a compound (Y) having two or more phenolic hydroxyl groups in one molecule, an inorganic base or an organic base, and a tetra-substituted phosphonium halide.
The substituents of the tetra-substituted phosphonium halide are not particularly limited, and the substituents may be the same or different. For example, a tetra-substituted phosphonium ion having a substituted or unsubstituted aryl or alkyl group as a substituent is preferable because it is stable against heat and hydrolysis. Specifically, tetraphenylphosphonium, tetratolylphosphonium, tetraethylphenylphosphonium, tetramethoxyphenylphosphonium, tetranaphthylphosphonium, tetrabenzylphosphonium, ethyltriphenylphosphonium, n-butyltriphenylphosphonium, 2-hydroxyethyltriphenylphosphonium, Examples include trimethylphenylphosphonium, methyldiethylphenylphosphonium, methyldiallylphenylphosphonium, tetra-n-butylphosphonium and the like. Examples of the halide include chloride and bromide, and it may be selected from properties such as price and moisture absorption of the tetra-substituted phosphonium halide, and availability.
Either one can be used.

In addition, other curing accelerators such as triphenylphosphine, 1,8-diazabicyclo (5,4,0) undecene-7 and 2-methylimidazole may be used as long as the properties of the molecular compound of the present invention are not impaired. There is no problem if used together. The compounding amount of the molecular aggregate is 0.5 parts per 100 parts by weight of the total weight of all epoxy resins and all phenol resins.
About 20 parts by weight is preferable because the curability, storage stability and other properties are well balanced.

The red phosphorus or red phosphorus flame retardant used in the present invention comprises:
It acts as a flame retardant. As the red phosphorus, fine particles made of red phosphorus obtained by directly spheroidizing yellow phosphorus and an aggregate thereof are preferable because the fluidity during molding of the epoxy resin composition is improved. The red phosphorus-based flame retardant is not particularly limited, but is preferably one in which the surface of red phosphorus is coated with an inorganic compound and / or a curable resin. When the inorganic compound and the curable resin are used in combination for coating, any of the inorganic compound layer and the curable resin layer coated on the red phosphorus may be either inside or outside, or the inorganic compound and the curable resin. May be mixed and used for coating. In particular, it is preferable to use a material obtained by coating the surface of red phosphorus with an inorganic compound and then further coating the surface with a curable resin, because phosphate ions and phosphite ions that elute can be suppressed.

The inorganic compound used for the coating is not particularly limited, but examples thereof include metal hydroxides, metal oxides, metal nitrides, metal salts with inorganic or organic acids, and the like. In particular, a metal hydroxide or a metal oxide having an effect of suppressing hydrolysis of red phosphorus is preferable, and a hydroxide or an oxide of aluminum, magnesium, or zinc is more preferable. These inorganic compounds may be used alone or in combination of two or more.

The curable resin used for the coating is not particularly limited. For example, a phenol resin, an epoxy resin, a xylene / formaldehyde resin, a ketone resin
Formaldehyde resin, urea resin, melamine resin, aniline resin, alkyd resin, unsaturated polyester resin and the like, phenolic resin, especially those that do not decrease the fluidity and curability during molding of the low hygroscopicity and epoxy resin composition, Epoxy resins are preferred. These curable resins may be used alone or in combination of two or more. The method for curing the curable resin may be normal temperature or heating, and is not particularly limited.

That is, as the red phosphorus-based flame retardant of the present invention, it is more preferable that the surface of red phosphorus is coated with aluminum hydroxide and then further coated with a phenol resin and / or an epoxy resin. There is no restriction on the coating method, but for example, from the viewpoint of coating uniformity, red phosphorus is coated by reducing aluminum sulfate, aluminum nitrate, etc. in the liquid phase to change to aluminum hydroxide. Further, a method of using an acid in a resole resin solution, coating with a generated phenol resin, and drying is used.

The phenolic resin used for coating is not particularly limited, but includes all monomers, oligomers and polymers having two or more phenolic hydroxyl groups in one molecule, such as phenol novolak resin and cresol novolak resin. And a novolak resin or a resole resin. These may be used alone or in combination of two or more. As the epoxy resin used for coating,
Although not particularly limited, it refers to monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule, and includes, for example, a biphenyl-type epoxy resin, a bisphenol-type epoxy resin, and a novolak-type epoxy resin. May be used alone or in combination of two or more.

The content of red phosphorus in the red phosphorus flame retardant is as follows:
90-96% by weight is preferred. If it is less than 90% by weight, the coating layer becomes thick and its effect as a flame retardant decreases, and if it exceeds 96% by weight, the coating layer becomes thin and undergoes a hydrolysis reaction in the presence of moisture, so that phosphoric acid is easily converted from red phosphorus. Since ions and phosphite ions are generated, a problem may occur in terms of moisture resistance. As red phosphorus or red phosphorus-based flame retardants, the average particle size is 2 to
Those having a size of 8 μm and a maximum particle size of 20 μm or less are preferred. If the average particle size is less than 2 μm, agglomeration or the like will occur, and if it exceeds 8 μm, the dispersibility may be reduced. In order to improve dispersibility, those having a maximum particle size of 20 μm or less are preferable,
If it exceeds 0 μm, the dispersibility tends to decrease. Examples of the coated red phosphorus-based flame retardant include Rin Kagaku Kogyo Co., Ltd.
Nova Excel etc. can be easily obtained from the market. The content of red phosphorus or a red phosphorus-based flame retardant is preferably 0.2 to 2% by weight in the total epoxy resin composition. 0.2
If it is less than 2% by weight, the flame retardancy may be insufficient, and if it exceeds 2% by weight, the moisture resistance may be significantly reduced.

The type of the inorganic filler (E) used in the present invention is not particularly limited, and those generally used for a sealing material can be used. For example, fused silica, fused spherical silica, crystalline silica, secondary aggregated silica,
Alumina, silicon nitride, aluminum hydroxide, talc, clay, glass fiber and the like can be mentioned. In particular, fused silica and crystalline silica are desirable from the viewpoint of the difference in linear expansion coefficient from the Si chip and the lead frame and the amount of impurities. The content of the inorganic filler is preferably 70 to 95% by weight in the entire epoxy resin composition from the balance between moldability and reliability. In addition, from the viewpoint of fluidity and filling properties, the inorganic filler has an average particle size of 11 to 20 μm.
m and a particle size of 10 μm or less in all inorganic fillers.
Those having a particle size distribution of about 45% by weight and a particle size of 70 μm or more and 10% by weight or less are preferable. In particular, in a composition having a large amount of inorganic filler, spherical fused silica is generally used.
The content of the inorganic filler is the total amount of the inorganic filler and the inorganic compound used for coating the red phosphorus, and is the total amount of the epoxy resin including the epoxy resin and the phenol resin used for the coating of the red phosphorus, and 200 to 2400 parts by weight per 100 parts by weight of the total amount of the phenol resin is preferred. If the amount is less than 200 parts by weight, the reinforcing effect of the inorganic filler may not be sufficiently exhibited. If the amount is more than 2400 parts by weight, the fluidity of the epoxy resin composition may be reduced and poor filling may occur during molding. Not preferred. In particular, the content of the inorganic filler is the total amount of all epoxy resins and all phenolic resins being 1
When the amount is 250 to 1400 parts by weight per 00 parts by weight, the moisture absorption of the cured product of the epoxy resin composition is low, so that the occurrence of solder cracks can be prevented, and the viscosity of the epoxy resin composition at the time of melting is low. Therefore, there is no possibility of causing gold wire deformation inside the semiconductor device, which is more preferable.
It is preferable that the inorganic filler is sufficiently mixed in advance.

The ion scavenger used in the present invention reduces ionic impurities contained in resins and the like by trapping halogen anions, organic acid anions, alkali metal cations, alkaline earth metal cations and the like.
It is known that aluminum corrodes due to ionic impurities, and by capturing ionic impurities,
Corrosion reaction of aluminum can be prevented. The ion scavenger, for _{example, BiO X (OH) Y (} NO 3) Z [wherein, X = 0.9~1.1, Y = 0.6~0.8 , Z =
0.2-0.4], Mg _4.3 Al ₂ (OH) _12.6 CO _{3.
3.5H 2 O, Sb 2 O 5} · 2H 2 O, SbSi V Bi W O X
(OH) _Y (NO ₃ ) _Z · nH ₂ O [where V = 0.1 to
0.3, W = 1.5-1.9, X = 4.1-4.5, Y
= 0.6-0.8, Z = 0.2-0.3, n = 1-2]
Among them, in particular, BiO _X (OH) _Y
(NO ₃ ) _Z [where X = 0.9 to 1.1, Y = 0.6
0.8, Z = 0.2-0.4], and / or Mg _4.3
Al ₂ (OH) _12.6 CO ₃ · 3.5 H ₂ O is more preferable because it selectively captures anions.
It may be used in combination of more than one kind. The content of the ion scavenger is 0.2 to 2% by weight in the whole epoxy resin composition.
Is preferred. If it is less than 0.2% by weight, reliability is insufficient, and 2
If the content exceeds 10% by weight, the flame retardancy is reduced. These can be easily obtained from the market.

The epoxy resin composition of the present invention comprises (A)
(E) In addition to the component and the ion scavenger, if necessary, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a coloring agent such as carbon black, a brominated epoxy resin, an antimony oxide, a phosphorus compound, and the like. Various additives such as a fuel, low-stress components such as silicone oil and silicone rubber, release agents such as natural waxes and synthetic waxes, higher fatty acids and their metal salts or paraffin, and antioxidants can be blended. The epoxy resin composition of the present invention is prepared by mixing the components (A) to (E) with an ion scavenger, other additives, and the like at room temperature using a mixer, kneading with a kneading machine such as a roll or an extruder, and cooling. It is obtained by subsequent grinding. In order to manufacture a semiconductor device by encapsulating an electronic component such as a semiconductor element using the epoxy resin composition of the present invention, it is sufficient to cure and mold by a molding method such as a transfer mold, a compression mold, and an injection mold. In particular, the epoxy resin composition of the present invention is suitable for a semiconductor device compatible with insertion mounting and surface mounting.

[0026]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. [Synthesis example of molecular aggregate] (Synthesis example 1) Bisphenol F manufactured by Honshu Chemical Industry Co., Ltd.
-D (corresponding to compound (Y)) 300 g (1.5 mol)
And 329 g (0.5 mol) of tetraphenylphosphonium / tetraphenylborate (Z) were charged into a 3 L separable flask and reacted at 200 ° C. for 3 hours. The amount of benzene distilled in this reaction was 97% by weight of the theoretical amount.
(That is, the benzene distillation rate was 97%). The crude product of this reaction is finely pulverized and charged into a separable flask,
2-propanol was added in an amount 3 times the charged weight of the crude product, and the mixture was stirred at an internal temperature of 82.4 ° C (boiling point temperature of 2-propanol) for 1.5 hours. Thereafter, most of the 2-propanol was removed, and a low-boiling component was further removed under heating and reduced pressure. The obtained product was designated as compound C1. The compound C1 was measured by ¹ H-NMR using heavy solvent as a solvent. The peaks around 4.8 ppm and 3.3 ppm are the peaks of the solvent, and the peak group around 6.4 to 7.1 ppm is the starting material bisphenol F [the number of moles (a) relative to 1 mole of (X) (X)] Phenyl protons of a phenoxide type conjugate base obtained by removing one hydrogen from bisphenol F [moles (b) per mol of (X)], 7.6 to
The peak group around 8.0 ppm was assigned to the phenyl proton of the tetraphenylphosphonium group, and from the area ratio thereof, the molar ratio was calculated to be (a + b) / (X) = 2.2 / 1.

(Synthesis Example 2) 300 g (1.5 mol) of bisphenol FD (equivalent to compound (Y)) manufactured by Honshu Chemical Industry Co., Ltd. 314 g (0.75 mol) of tetraphenylphosphonium bromide and 3000 g of methanol were charged and completely dissolved. Sodium hydroxide 3
A methanol / water mixed solution containing 0 g was added dropwise with stirring. A reprecipitation operation of dropping the obtained solution into a large amount of water was performed to obtain the target substance as a solid. The solid was removed by filtration, and the product obtained by drying was designated as compound C2. The solvent was deuterated methanol, and the ¹ H
-Measurement by NMR was performed. Around 4.8 ppm and 3.
The peak around 3 ppm is the peak of the solvent, 6.4 to 7.
The peak group around 1 ppm is composed of the starting material bisphenol F [moles (a) based on 1 mol of (X)] and the phenoxide-type conjugate base obtained by removing one hydrogen from this bisphenol F [moles per 1 mol of (X). The phenyl proton of the number (b)] and the peak group around 7.6 to 8.0 ppm are assigned to the phenyl proton of the tetraphenylphosphonium group, and from the area ratio thereof, the molar ratio is (a + b).
/ (X) = 2/1 was calculated.

[Production Example of Epoxy Resin Composition] The mixing ratio is by weight. (Example 1) Biphenyl type epoxy resin (YX4000H, manufactured by Yuka Shell Epoxy Co., Ltd., melting point: 108 ° C, epoxy equivalent: 195 g / eq) 8.8 parts by weight Phenol novolak resin (softening point: 80 ° C, hydroxyl equivalent: 105 g / eq) 4.6 parts by weight Compound C1 0.4 parts by weight Red phosphorus flame retardant 1 (Red phosphorus converted directly from yellow phosphorus into spheres is coated with aluminum hydroxide, and then coated with phenolic resin.) (Red phosphorus content: 94% by weight, average particle size: 4.5 μm, maximum particle size: 11 μm) 0.4 part by weight Fused spherical silica 84.8 parts by weight Carbon black 0.5 part by weight Carnauba wax 0.5 part by weight Parts at room temperature using a mixer and mixed at 70-100 ° C.
The mixture was kneaded using a shaft roll, cooled and pulverized to obtain an epoxy resin composition. The obtained epoxy resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method: Spiral flow: Using a mold for measuring spiral flow according to EMMI-1-66, mold temperature 175
C., an injection pressure of 6.9 MPa, and a curing time of 120 seconds. Spiral flow is a parameter of fluidity, and the larger the value, the better the fluidity. The unit is cm. -Shore D hardness: mold temperature 175 ° C, injection pressure 6.9M
Molding was performed at Pa and a curing time of 40 seconds, and the value of Shore D hardness measured 10 seconds after opening the mold was defined as curability. Shore D hardness is an index of curability, and the larger the numerical value, the better the curability. -Flame retardancy: 175 using low pressure transfer molding machine
A test piece was formed at a temperature of ℃, a pressure of 6.9 MPa, and a curing time of 120 seconds. UL-94 vertical test (specimen thickness 1.0mm)
Was done. -Moisture resistance: 175 using a low pressure transfer molding machine
3mm × at 6.9MPa, pressure 6.9MPa, curing time 120 seconds
A 3.5 mm semiconductor element is sealed in 16 pDIP,
Post-curing was performed at 5 ° C. for 8 hours. A pressure cooker test (125 ° C., 0.24 MPa) was performed, and open failures of the circuit were measured every 50 hours and expressed as failure occurrence times. The unit is time.・ High-temperature storage characteristics: Using a low-pressure transfer molding machine
3m at 175 ° C, pressure 6.9MPa, curing time 120 seconds
A semiconductor element of mx 3.5 mm is sealed in 16pDIP,
Post cure was performed at 175 ° C. for 8 hours. A high-temperature storage test (185 ° C., 1000 hours) was performed, and a package in which the electric resistance between wirings increased by 20% from the initial value was determined to be defective. The percentage of defective numbers in 15 packages (rejection rate) was expressed as a percentage. Units%. -Storage at 25 ° C: After storing at 25 ° C for 14 days, the spiral flow was measured and expressed as a percentage of the spiral flow immediately after preparation. Units%.

(Examples 2 to 7, Comparative Example 1, Comparative Example 2) According to the formulations in Tables 1 and 2, an epoxy resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. . The results are shown in Tables 1 and 2. The materials used in Examples and Comparative Examples are shown below. DBU: 1,8-diazabicyclo (5,4,0) undecene-7 Red phosphorus-based flame retardant 2: Ground red phosphorus is coated with aluminum hydroxide and then coated with phenol resin With a red phosphorus content of 94% by weight and an average particle size of 5.0μ
m, maximum particle size 15 μm. Ion scavenger _{1: BiO X (OH) Y} (NO 3) Z [wherein, X = 0.9~1.1, Y = 0.6~0.8 , Z =
0.2 to 0.4] -Ion scavenger 2: Mg _4.3 Al ₂ (OH) _12.6 CO _3.
3.5H ₂ O ・ brominated bisphenol A type epoxy resin ・ antimony trioxide

[Table 1]

[0031]

[Table 2]

[0032]

The epoxy resin composition of the present invention does not contain halogen and antimony and is excellent in flame retardancy, rapid curing, fluidity, moisture resistance and high-temperature storage characteristics. A sealed semiconductor device has excellent moisture resistance and is useful as a semiconductor device compatible with insertion mounting and surface mounting.

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Claims (17)

[Claims] 1. A compound (Y) having (A) an epoxy resin, (B) a phenolic resin, (C) a tetra-substituted phosphonium (X) and two or more phenolic hydroxyl groups in one molecule, and a phenolic compound in one molecule. A molecular association with a conjugate base of a compound (Y) having two or more hydroxyl groups, wherein the conjugate base removes one hydrogen from the compound (Y) having two or more phenolic hydroxyl groups in one molecule. An epoxy resin composition comprising, as essential components, a curing accelerator comprising a phenoxide-type compound, (D) red phosphorus or a red phosphorus-based flame retardant, and (E) an inorganic filler. 2. The compound (Y) having two or more phenolic hydroxyl groups in one molecule is selected from dihydroxybenzenes, trihydroxybenzenes, bisphenols, biphenols, dihydroxynaphthalenes, phenol novolak resins and phenol aralkyl resins. The epoxy resin composition according to claim 1, which is at least one member selected from the group consisting of: 3. The method according to claim 1, wherein the molecular aggregate reacts the tetra-substituted phosphonium / tetra-substituted borate (Z) with a compound (Y) having two or more phenolic hydroxyl groups in one molecule at a high temperature, and further reacts the compound. The epoxy resin composition according to claim 1, which is obtained by a thermal reaction in a solvent having a boiling point of 60 ° C. or higher. 4. The molecular aggregate is obtained by reacting a compound (Y) having two or more phenolic hydroxyl groups in one molecule, an inorganic base or an organic base, and a tetra-substituted phosphonium halide. Item 4. The epoxy resin composition according to any one of Items 1 to 3. 5. The epoxy resin composition according to claim 1, wherein the tetra-substituted phosphonium (X) is tetraphenylphosphonium. 6. The epoxy resin (A) having a melting point of 50 to 15
The epoxy resin composition according to any one of claims 1 to 5, which is a crystalline epoxy resin at 0 ° C. 7. The epoxy resin composition according to claim 6, wherein the crystalline epoxy resin having a melting point of 50 to 150 ° C. is at least one selected from the general formulas (1) and (2). Embedded image (Wherein, R ¹ is a group or an atom selected from a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and may be the same or different from each other. Good.) (Wherein, R ² is a group or atom selected from a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and may be the same or different. Good.) 8. The crystalline epoxy resin having a melting point of 50 to 150 ° C. is a mixture of a stilbene type epoxy resin represented by the general formula (3) and a stilbene type epoxy resin represented by the general formula (4). The epoxy resin composition according to the above. Embedded image (Wherein, R ^{3 to} R ¹⁰ each independently represent a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, or a group or atom selected from halogen. However, carbon-carbon (The two aryl groups bonded to the double bond are different from each other.) (Wherein, R ^{11 to} R ¹⁴ each independently represent a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, and a group or atom selected from halogen. However, carbon-carbon The two aryl groups bonded to the double bond are the same as each other.) 9. The epoxy resin composition according to claim 1, wherein the phenol resin (B) is a phenol aralkyl resin. 10. A red phosphorus or red phosphorus flame retardant having an average particle size of 2
The epoxy resin composition according to any one of claims 1 to 9, wherein the epoxy resin composition has a maximum particle diameter of 20 µm or less. 11. The epoxy resin composition according to claim 1, wherein the red phosphorus-based flame retardant is obtained by coating the surface of red phosphorus with an inorganic compound and / or a curable resin. 12. The epoxy resin according to claim 1, wherein the red phosphorus-based flame retardant is obtained by coating the surface of red phosphorus with an inorganic compound and then coating the surface with a curable resin. Composition. 13. The epoxy resin composition according to claim 11, wherein the inorganic compound is a metal hydroxide or a metal oxide. 14. The epoxy resin composition according to claim 13, wherein the metal hydroxide is a hydroxide of aluminum, magnesium, or zinc, and the metal oxide is an oxide of aluminum, magnesium, or zinc. 15. The epoxy resin composition according to claim 11, wherein the curable resin is a phenol resin or an epoxy resin. 16. The total epoxy resin composition contains BiO _X
(OH) _Y (NO ₃ ) _Z [where X = 0.9 to 1.1, Y
= 0.6-0.8, Z = 0.2-0.4] and / or Mg _4.3 Al ₂ (OH) _12.6 CO ₃ .3.5H ₂ O with an ion scavenger of 0.2-2. The epoxy resin composition according to any one of claims 1 to 15, wherein the composition comprises 1% by weight. 17. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition according to claim 1. Description: