JPH08283379A - Semiconductor sealing material - Google Patents

Abstract

PURPOSE: To obtain a semiconductor sealing material which can cope with higher mounting densities because of very good flowability and also has good shelf stability by using as the principal component a polyepoxy compound having specified groups as the epoxy groups. CONSTITUTION: This material is composed essentially of a polyepoxy compound having β-alkylglycidyl groups as the epoxy groups, a curing agent, and an inorganic filler. Examples of preferable polyepoxy compounds having β- alkylglycidyl groups include di-β-alkylglycidyl ethers of bisphenols and β- alkylglylcidyl ethers of naphthols, among which di-β-alkylglycidyl ethers of hydroxynaphthalene are preferable in particular. A preferable β-alkylglycidyl group is a β-methylglycidyl group. The polyepoxy compound is obtained by, for example, the condensation of a β-methylepihalohydrin and a polyhydric phenol compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel semiconductor encapsulating material having excellent storage stability and fluidity.

[0002]

2. Description of the Related Art In recent years, semiconductor packages have tended to be thinned in response to higher packaging density, and have a thickness of 1 mm or less.
SOP type packages are also being used. Correspondingly, as the semiconductor sealing material, a material having higher fluidity is required.

Up to now, an epoxy composition for a semiconductor encapsulating material using an ortho-cresol novolac type epoxy resin (hereinafter referred to as "ECN") has been widely used as an epoxy resin for a semiconductor encapsulating material. Although the semiconductor encapsulant using (1) has excellent heat resistance, it has a drawback that it has a high melt viscosity and therefore has a markedly poor fluidity, making it difficult to cope with the high packaging density. on the other hand,
Semiconductor encapsulants that use liquid bisphenol epoxy resin are also known, but due to their low melt viscosity, encapsulants with good fluidity can be provided, but they have poor heat resistance and cannot be put to practical use. In addition, the storage stability was extremely poor.

Therefore, conventionally, as a semiconductor encapsulating material which is excellent in fluidity and heat resistance and can cope with high packaging density,
For example, a semiconductor sealing material using a naphthalene-based epoxy resin obtained by reacting 1,6-dihydroxynaphthalene with epichlorohydrin as a main component is known.

[0005]

However, a semiconductor encapsulating material using a naphthalene-based epoxy resin obtained by reacting 1,6-dihydroxynaphthalene with epichlorohydrin as a main component has a low melt viscosity and excellent fluidity, The storage stability of the semiconductor encapsulating material is extremely poor. Therefore, in practical use, there is a major problem that the curing becomes faster than at the time of design and the flow is shortened, causing a problem in moldability.

The problem to be solved by the present invention is to provide a semiconductor encapsulating material having both excellent storage stability and fluidity.

[0007]

Means for Solving the Problems As a result of intensive studies by the present inventors, the inventors have found the above-mentioned problems and completed the present invention by using a polyvalent epoxy compound having a β-alkylglycidyl group as an epoxy group as a main agent. I arrived.

That is, the present invention is characterized in that a polyvalent epoxy compound (A) having a β-alkylglycidyl group as an epoxy group, a curing agent (B), and an inorganic filler (C) are essential components. The present invention relates to a sealing material.

In the polyvalent epoxy compound (A) having a β-alkylglycidyl group as an epoxy group, the β-alkylglycidyl group is not particularly limited, but for example, β-methylglycidyl group and β-ethylglycidyl group. Group, a β-propylglycidyl group, a β-butylglycidyl group, and the like. Among them, the β-methylglycidyl group is preferable from the viewpoint of excellent storage stability.

Specific examples of the above-mentioned polyepoxy resin having a β-alkylglycidyl group include di-β-alkylglycidyl ether of bisphenol A, di-β-alkylglycidyl ether of bisphenol F and diphenol of bisphenol S. Represented by -β-alkyl glycidyl ether, bisphenol di-β-alkyl glycidyl ether; biphenol di-β-alkyl glycidyl ether, tetramethyl biphenol di-β
-Di-β-alkyl glycidyl ethers of biphenols represented by alkyl glycidyl ethers; β-alkyl glycidyl ethers of naphthols represented by di-β-alkyl glycidyl ethers of dihydroxynaphthalene and di-β-alkyl glycidyl ethers of binaphthol Ether; poly-β-alkyl glycidyl ether of phenol-formaldehyde polycondensate; poly-β-alkyl glycidyl ether of cresol-formaldehyde polycondensate C1-C10 monoalkyl-substituted phenol-formaldehyde polycondensate typified by poly-β-alkyl glycidyl ether -Β-alkyl glycidyl ether; C1 to C10 dialkyl-substituted phenol-formaldehyde polycondensate typified by poly-β-alkyl glycidyl ether of xylenol-formaldehyde polycondensate Poly-β-alkyl glycidyl ethers; bisphenols represented by poly-β-alkyl glycidyl ethers of bisphenol A-formaldehyde polycondensates-Poly-β-alkyl glycidyl ethers of formaldehyde polycondensates; phenols and dicyclopentadiene, Examples thereof include poly-β-alkylglycidyl ethers which are polyaddition products of cyclic dienes such as limonene and pinene; poly-β-alkylglycidyl ethers which are polyaddition products of phenols and divinylbenzene.

Among them, di-β-alkyl glycidyl ethers of bisphenols and β-alkyl glycidyl ethers of naphthols are preferable from the viewpoints of good fluidity and storage stability, and particularly excellent heat resistance. The di-β-alkyl glycidyl ether of dihydroxynaphthalene is preferable from the viewpoints of good heat resistance, fluidity and storage stability. There are several isomers of di-β-alkyl glycidyl ether of dihydroxynaphthalene, but among them, 1,6 from the viewpoint of excellent heat resistance.
Di-β-alkyl glycidyl ethers of dihydroxynaphthalene are preferred.

The above-mentioned polyvalent epoxy compound (A) does not need to be a compound in which all epoxy groups are β-alkylglycidyl groups, as in the above-mentioned compounds, and a part of them is a glycidyl group. May be. It can also be used in the coexistence with an epoxy compound having only a glycidyl group.

A method for obtaining such a polyhydric epoxy compound (A) is not particularly limited, but a method of condensing β-methylepihalohydrin and a polyhydric phenol compound can be mentioned. It is preferable to use (A ′) as the epoxy resin component containing the polyvalent epoxy compound (A).

The β-alkyl epihalohydrin used here is not particularly limited, but β-methyl epichlorohydrin, β-methyl epibromohydrin, β-methyl epifluorohydrin, and other β-methyl epichlorohydrin are used. Β-ethyl epihalohydrin such as epihalohydrin, β-ethylepichlorohydrin, β-ethylepibromohydrin, β-ethylepifluorohydrin, β-propylepichlorohydrin, β-propylepibromohydrin, β
-Β-propyl epihalohydrin such as propyl epifluorohydrin, β-butyl epichlorohydrin, β-butyl epibromohydrin, β-butyl epihalohydrin such as β-butyl epifluorohydrin, and the like. Β-Methylepihalohydrin is preferred from the viewpoint of reactivity with polyhydric phenol and fluidity.

As the polyphenol compound, 1
The kind is not limited as long as it is a compound containing two or more aromatic hydroxyl groups in the molecule, but exemplarily includes bisphenols such as bisphenol A, bisphenol F and bisphenol S, and biphenols such as biphenol and tetramethylbiphenol. , Dihydroxynaphthalene,
Naphthols such as binaphthol, phenol novolac resins represented by phenol-formaldehyde polycondensates, C1 to C10 monoalkyl-substituted phenol-formaldehyde polycondensates represented by cresol-formaldehyde polycondensates, xylenol-formaldehyde polycondensates C1 to C10 dialkyl-substituted phenol-formaldehyde polycondensate, bisphenol A-
Bisphenols-formaldehyde polycondensates typified by formaldehyde polycondensates, other copolycondensates of phenol with C1 to C10 monoalkyl-substituted phenols and formaldehyde, phenols with dicyclopentadiene, limonene, pinene, etc. Examples thereof include polyaddition products with diene and polyaddition products with phenols and divinylbenzene. Among them, bisphenols and naphthols are preferable from the viewpoints of fluidity and storage stability, and dihydroxynaphthalene is preferable from the viewpoint that heat resistance is particularly good and heat resistance, fluidity and storage stability are good.
In addition, although dihydroxynaphthalene has several isomers as in the case of the specific examples of the polyvalent epoxy compound (A), 1,6-dihydroxynaphthalene is preferable from the viewpoint of excellent heat resistance.

When producing the condensation reaction product (A '),
The reaction may be performed using only β-alkylepihalohydrin, but the fluidity can be further improved by partially using epihalohydrin together depending on the purpose. However, by increasing the use ratio of β-alkyl epihalohydrin, the storage stability becomes extremely excellent, and further, the effect that the amount of impurity chlorine contained in the epoxy resin is further reduced is expressed, so the mixing ratio thereof Can be appropriately adjusted depending on the application and required characteristics.

From the viewpoint of achieving a good balance of these characteristics, the β-alkyl epihalohydrin / epihalohydrin molar ratio is preferably in the range of 90/10 to 30/70,
Especially, the range of 80/20 to 40/60 is preferable.

When the β-alkyl epihalohydrin and epihalohydrin are used in combination with the polyhydric phenol as described above, the condensation reaction product (A ') obtained has all the epoxy groups of the β-alkylglycidyl group. (Compound (A)), a compound in which a β-alkylglycidyl group and a glycidyl group coexist in the compound (Compound (A)), a compound in which all epoxy groups are glycidyl groups,
And are mixed.

Further, since the condensation reaction product (A ') uses β-alkylepihalohydrin as a raw material component thereof, it also has an effect of reducing the total chlorine content in the condensation reaction product (A'). That is, when the total chlorine content is large, there is a problem of causing wiring corrosion in a semiconductor package, but in the present invention, the total chlorine content is reduced,
The reliability can be increased. The specific total chlorine amount is not particularly limited, but the total chlorine amount in the condensation reaction product (A ′) is preferably 800 ppm or less.

The above-mentioned method for producing the condensation reaction product (A ') is
Although not particularly limited, the following methods are specifically mentioned. First, 2 to 15 equivalents of β-methylepichlorohydrin or a mixture of β-methylepichlorohydrin and epichlorohydrin with respect to the hydroxyl group in the polyhydric phenol compound are added and dissolved, and then in the polyhydric phenol compound. 0.8 to 1.2 equivalent of 1 with respect to the hydroxyl group of
0 to 50% NaOH aqueous solution at a temperature of 50 to 80 ° C. for 3 to
It takes 5 hours and is suitable. After a suitable temperature, stirring is continued for 0.5 to 2 hours at that temperature, and after standing, the lower layer saline is discarded.
Then, excess epihalohydrin is recovered by distillation to obtain a crude resin. To this, an organic solvent such as toluene or MIBK is added, and the desired resin can be obtained through the steps of washing with water, dehydration, filtration and desolvation. A solvent such as dioxane or DMSO may be used together during the reaction for the purpose of reducing the amount of impurity chlorine.

Since the compound (A) or the condensation reaction product (A ') in the present invention has a remarkably low melt viscosity, the inorganic filler can be highly filled, and the heat resistance and water resistance of the molded product are remarkably improved. The solder crack resistance is remarkably improved. In addition, even if highly filled with an inorganic filler, the obtained material has excellent fluidity, so that it can be easily molded into a thin semiconductor package. In addition, it is a property that contradicts high fluidity. It also has stability. Further, as described above, since a low total chlorine content of the epoxy resin can be achieved, it becomes a semiconductor encapsulating material that also has high reliability such as prevention of wiring corrosion.

The condensation reaction product (A ') containing the compound (A) detailed above further comprises a curing agent (B) and an inorganic filler (C).
By blending with, the intended semiconductor encapsulating material can be obtained.

Here, the curing agent (B) is not particularly limited as long as it is a compound having an active hydrogen atom capable of reacting with an epoxy group, and is not particularly limited, but two phenolic hydroxyl groups are contained in one molecule. It is a compound containing the above,
It is preferable in terms of curing characteristics and heat resistance, and if it is exemplified, it is a phenol novolac resin typified by a phenol-formaldehyde polycondensate, or a C1 to C10 monoalkyl-substituted phenol-formaldehyde polycondensate typified by a cresol-formaldehyde polycondensate. C1 to C1 represented by condensate and xylenol-formaldehyde polycondensate
0 dialkyl-substituted phenol-formaldehyde polycondensate, bisphenol-formaldehyde polycondensate typified by bisphenol A-formaldehyde polycondensate, and other copolycondensates of phenol and C1 to C10 monoalkyl-substituted phenol and formaldehyde , Polycycloaddition products of phenols with cyclic dienes such as dicyclopentadiene, limonene, and pinene, and polyaddition products of phenols with divinylbenzene.

Among them, phenol-formaldehyde polycondensate, cresol novolac-formaldehyde polycondensate and dicyclopentadiene-phenol polyadduct are particularly preferable because they have excellent curability and heat resistance.

When each of the compounds described above is used as a curing agent, a curing accelerator can be used appropriately. As the curing accelerator, any conventionally known one can be used, and examples thereof include tertiary amines, imidazoles, organic acid metal salts, amine complex salts, phosphorus compounds such as triphenylphosphine, and the like. Not only alone but also two or more kinds can be used in combination.

The inorganic filler (C) used in the present invention is an essential component for not only enhancing the mechanical strength of the cured product, but also achieving low water absorption and low linear expansion coefficient and enhancing the solder crack preventing effect. Although not specifically limited, examples thereof include powdered silica, alumina, talc, clay, and glass fiber, and powdered silica is particularly preferable from the viewpoint of excellent moisture resistance and solder crack resistance.

Specific examples of the powdered silica include fused silica, crystalline silica, spherical silica, pulverized silica and the like. Among them, fused silica is preferable from the viewpoint of excellent fluidity.

The particle size of the inorganic filler (C) is not particularly limited, but a small particle size such as 5 microns or less is preferable.
Further, those having various particle size distributions can be used in order to improve the fluidity.

The compounding amount of the inorganic filler (C) is not particularly limited, but the larger the compounding amount is, the more preferable the mechanical strength and the effect of preventing solder cracks are. Specifically, in the composition 80-
It is preferable to use it in the range of 95% by weight from the viewpoint that those characteristics will be outstanding.

The composition of the present invention further impairs the properties of the composition of the present invention in addition to the above-mentioned compound (A) or condensation reaction product (A ') containing the compound (A) which is an essential component. Other epoxy resins may be used in combination as long as there is no range.

As the other epoxy resin used at this time, any of the known and commonly used ones can be used. For example, bisphenol A diglycidyl ether type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, bisphenol A novolac. Type epoxy resin, bisphenol F novolac type epoxy resin, brominated phenol novolac type epoxy resin, naphthol novolac type epoxy resin, biphenyl type bifunctional epoxy resin, polyglycidyl ether of a condensate of hydroxybenzaldehyde and phenols, and the like. However, the present invention is not limited to these. Among these, the orthocresol novolac type epoxy resin is preferable because of its excellent heat resistance, and the biphenyl type bifunctional epoxy resin is preferable because of its excellent fluidity.

Further, if necessary, various well-known and commonly used additive components such as a colorant, a flame retardant, a release agent, a stress-reducing agent such as silicone oil or silicone resin, a coupling agent and the like may be appropriately blended. it can.

Next, in order to prepare a desired semiconductor encapsulating material from the above-mentioned components, the polyvalent epoxy compound (A) is used.
Alternatively, after the condensation reaction product (A ′), the curing agent (B) and the inorganic filler (C), and if necessary, the curing accelerator, the additive, and the other epoxy resin are sufficiently and uniformly mixed by a mixer or the like, Further, it is carried out by melt-kneading with a hot roll or a kneader, cooling and pulverizing, and further forming into tablets by a forming machine.

The semiconductor encapsulating material of the present invention thus obtained is a high-purity material having excellent storage stability and a small amount of impurity chlorine, and a molded semiconductor chip has remarkably excellent solder crack resistance. In addition, the low melting viscosity of the epoxy resin itself enables a high filling rate of the inorganic filler, and has excellent solder crack resistance.

The storage stability in the present invention is particularly good when the semiconductor sealing material is left at room temperature (20 to 35 ° C.) for 3 to 5 days.
The degree of reduction in curing time and the decrease in fluidity are small, and excellent moldability is exhibited.

[0036]

EXAMPLES Next, the present invention will be specifically described with reference to production examples, examples and comparative examples. In the examples, all parts are parts by weight unless otherwise specified.

The melt viscosity is Re at 50 Hz.
seach equipment LTD. `` ICI CONE & PLATE VISCOMET
ER ”.

The total chlorine content was measured by the following measuring method. After dissolving 0.3 g of the resin in 20 ml of n-BuOH, 1 g of metallic sodium is added and heat treatment is performed at 120 ° C. for 3 hours. The total content of chlorine was calculated from the appropriate quantity of the solution, which was determined by an appropriate titration method using an aqueous silver nitrate solution. The gel time was defined as the time when the mixture was heated and stirred at 175 ° C. and the fluidity was lost.

Production Example 1 228 g (1 mol) of bisphenol A was placed in a 4-necked flask equipped with a stirrer, a thermometer, and a decanter equipped with a condenser, and β-.
1065 g (10 mol) of methyl epichlorohydrin was added and dissolved. Under reduced pressure, 147 g (1.8 mol) of 48% NaOH aqueous solution was added dropwise at 80 ° C. over 3 hours while stirring. Meanwhile, the flask is heated to distill β-methylepichlorohydrin and water, and the decanter separates β-methylepichlorohydrin condensed in the condenser and water,
The β-methylepichlorohydrin was kept back in the flask. Continue stirring for another 30 minutes and then add 180g of water.
Was added and allowed to stand. The lower layer saline was discarded, and β-methylepichlorohydrin was distilled and collected at 150 ° C, then MIBK 400g was added to the crude resin, 3% NaOH aqueous solution 200g was further added, and the mixture was stirred at 80 ° C for 1 hour. Then, the lower water layer was discarded. After that, further the MIBK layer with water 2
After washing with 00 g of water and discarding the water, it is dehydrated and filtered, and then M
IBK was desolvated at 150 ° C. to obtain 352 g of the target epoxy resin (A). Melt viscosity at 150 ° C 0.08
Poise, epoxy equivalent 210g / eq, total chlorine 6
It was 40 ppm.

Production Example 2 β-Methylepichlorohydrin was mixed with 533 g (5 mol) of β-methylepichlorohydrin and epichlorohydrin 46.
300 g of epoxy resin was obtained in the same manner as in Production Example 1 except that the mixture was changed to 1 g (5 mol). This resin is 1
Melt viscosity at 50 ° C 0.06 poise, epoxy equivalent is 2
02 g / eq and total chlorine were 790 ppm.

Production Example 3 An epoxy resin (C) of 299 g was obtained in the same manner as in Production Example 1 except that 160 g of 1,6-dihydroxynaphthalene was used instead of bisphenol A. This resin is 1
Melt viscosity at 50 ° C 0.12 poise, epoxy equivalent is 1
The total chlorine content was 76 g / eq and 650 ppm.

Production Example 4 β-Methylepichlorohydrin was replaced with 852 g (8 mol) of β-methylepichlorohydrin and 18 epichlorohydrin.
296 g of an epoxy resin was obtained in the same manner as in Production Example 3 except that the mixture was changed to 5 g (2 mol). This resin is 1
Melt viscosity at 50 ° C 0.10 poise, epoxy equivalent is 1
It was 69 g / eq and total chlorine was 690 ppm.

Examples 1 to 7 and Comparative Examples 1 to 3 For comparison, EPICLON N-665 (Dainippon Ink and Chemicals, Inc.), which is an ortho-cresol novolac type epoxy resin, has a melt viscosity of 3.0 poise at 150 ° C. , Epoxy equivalent 208g / eq, total chlorine 1080ppm)
And EPICLON 850S, a condensation type epoxy resin of bisphenol A and epichlorohydrin (manufactured by Dainippon Ink and Chemicals, Inc .: melt viscosity at 150 ° C 0.04 poise, epoxy equivalent 188 g / eq, total chlorine 1450 p).
pm) and EPICLON which is a condensation type epoxy resin of 1,6-dihydroxynaphthalene and epichlorohydrin
HP-4032 (manufactured by Dainippon Ink and Chemicals, Inc .: 1
Melt viscosity at 50 ° C 0.08 poise, epoxy equivalent 150
g / eq, total chlorine 1720 ppm), and the following evaluation was performed.

The mixture prepared according to the formulations shown in Tables 1 and 2 was kneaded with a hot roll at 100 ° C. for 8 minutes and then pulverized to obtain 30 kg / m of a press molding machine.
The test piece for evaluation having a thickness of 2 mm was prepared by sealing under conditions of cm2, mold temperature 175 ° C, and molding time 100 seconds. Then, post-curing was performed at 175 ° C. for 8 hours. The blended amount of fused silica was adjusted so that the resulting blends had the same fluidity. In addition, as a phenol novolac curing agent, Phenolite TD-2131 (manufactured by Dainippon Ink and Chemicals, Inc .: hydroxyl group equivalent: 104 g / eq.) Was used.

Using this test piece for evaluation, the water absorption under the conditions of spiral flow of 175 ° C. and 85 ° C. and 85% RH,
And the glass transition temperature was measured by a dynamic viscoelasticity measuring instrument. In addition, as a storage stability test, the sealing material at
The spiral flow after storage for 2 hours was measured to determine the retention rate. Furthermore, a pressure cooker test was performed under the conditions of 160 ° C. × 20 hours and 4 atmospheres to measure the amount of chlorine ions in the extracted water. In addition, the test piece is 85 ℃ ・ 8
After being left for 72 hours in an atmosphere of 5% RH and subjected to a moisture absorption treatment, this was immersed in a solder bath at 260 ° C. for 10 seconds, and the crack occurrence rate at that time was examined to evaluate the solder crack resistance. 20 test pieces. The results are also shown in Table 1.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

According to the present invention, it is possible to provide a semiconductor encapsulating material which has excellent fluidity, can sufficiently cope with high packaging density, and has storage stability.

Claims (8)

[Claims] 1. A polyvalent epoxy compound (A) having a β-alkylglycidyl group as an epoxy group and a curing agent (B).
And a semiconductor encapsulating material, which comprises an inorganic filler (C) as an essential component. 2. The semiconductor encapsulating material according to claim 1, wherein the β-alkylglycidyl group is a β-methylglycidyl group. 3. The semiconductor encapsulating material according to claim 1, wherein the polyepoxy compound (A) is a β-alkyl glycidyl ether of a bisphenol or a β-alkyl glycidyl ether of a naphthol. 4. The semiconductor encapsulating material according to claim 1, 2 or 3, wherein the polyvalent epoxy compound (A) is used as a condensation reaction product (A ′) of β-alkylepihalohydrin and a polyvalent phenol compound. 5. The semiconductor encapsulating material according to claim 4, wherein the condensation reaction product (A ′) is a reaction product of β-alkylepihalohydrin, epihalohydrin and a polyhydric phenol compound. 6. The ratio of β-alkyl epihalohydrin to epihalohydrin used is 90 in terms of the former / latter molar ratio.
The semiconductor sealing material according to claim 5, which is / 10 to 30/70. 7. The total amount of chlorine in the condensation reaction product (A ′) is 8
The semiconductor encapsulating material according to claim 4, 5 or 6, wherein the content is 00 ppm or less. 8. The content of the inorganic filler (C) is 8 in the material.
The semiconductor encapsulating material according to claim 1, which is 0 to 95% by weight.