JP2001072831A - Liquid epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain liquid epoxy resin composition for sealing semiconductor, capable of preventing the generation of a peeling and crack and having high reliability. SOLUTION: This liquid state epoxy resin composition containing (A) a liquid state epoxy resin, (B) an inorganic filler and (C) an acid anhydride-based curing agent as essential components, is characterized by having >=500 ppm water contact in the inorganic filler, >=0.5 wt.% amount of a compound having carboxyl group contained in the acid anhydride and >=0.2 wt.% amount of a compound having the carboxyl group from the acid anhydride contained in the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitably used as a potting material or a coating material for a semiconductor device, and is particularly excellent in storage stability as a flip-chip underfill material and the like, and a semiconductor sealing material having excellent gap penetration. The present invention relates to a liquid epoxy resin composition for stopping.

[0002]

2. Description of the Related Art With the miniaturization, weight reduction, and enhancement of functions of electric equipment, semiconductor mounting methods have become the mainstream from pin insertion type to surface mounting. And one of bare chip mounting is flip chip (FC)
There is an implementation. FC mounting is a method in which several to thousands of electrodes called bumps having a height of about 10 to 100 μm are formed on the wiring pattern surface of an LSI chip, and the electrodes on the substrate are joined by a conductive paste or solder. For this reason, it is necessary that the sealing material used to protect the FC penetrates into a gap of about several tens of μm (normally about 40 μm to 20 μm) formed by bumps of the substrate and the LSI chip. The liquid epoxy resin composition used as the conventional underfill material for flip chips is composed of an epoxy resin, a hardener and an inorganic filler. In order to achieve the same, a formulation incorporating a large amount of an inorganic filler has become mainstream.

[0003] However, such an underfill material for a flip chip containing a large amount of an inorganic filler has a problem that it hardly penetrates into a narrow gap (about 40 μm to 20 μm), and the productivity is extremely deteriorated. This has been suggested and this improvement is desired. In this case, if the particle size of the inorganic filler is small, it can be easily presumed that the narrow gap can be accommodated.However, the reduction in the particle size causes an increase in the elastic modulus of the cured product, thereby relaxing the stress in the cured product. However, it has been pointed out that the problem is that the peeling and cracking easily occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid epoxy resin composition for semiconductor encapsulation which is prevented from peeling and cracking and has excellent reliability.

[0005]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, (A) a liquid epoxy resin, (B) an inorganic filler,
(C) An acid anhydride in which a liquid epoxy resin composition containing an acid anhydride-based curing agent uses an inorganic filler having a water content of 500 ppm or less and a carboxyl group-containing compound is 0.5% by weight or less. By using a compound-based curing agent and controlling the content of the compound having a carboxyl group in the composition to 0.2% by weight or less,
It has been found that peeling and cracking of the device chip after the reliability test can be suppressed.

That is, an acid anhydride can be used as a curing agent in an underfill material due to its low viscosity. However, if a large amount of a compound having a carboxyl group derived from the acid anhydride contained therein is contained in a large amount, the curability becomes poor. Was found to affect. At that time, by controlling the amount of water in the inorganic filler and the content of the compound having a carboxyl group derived from the acid anhydride in the acid anhydride-based curing agent, the acid anhydride in the liquid epoxy resin composition is controlled. That the content of the compound having a carboxyl group derived from the product can be controlled, and that the stress applied to the chip surface due to its curability can be uniformed, thereby preventing chip separation and cracking. The present inventors have found and found that the semiconductor device of the present invention sealed with the obtained liquid epoxy resin composition is very reliable, and have accomplished the present invention.

Accordingly, the present invention provides a liquid epoxy resin composition comprising (A) a liquid epoxy resin, (B) an inorganic filler, and (C) an acid anhydride-based curing agent as essential components. A compound having a content of not more than 500 ppm, a compound having a carboxyl group contained in the acid anhydride being 0.5% by weight or less, and having a carboxyl group from the acid anhydride contained in the composition; Provided is a liquid epoxy resin composition for semiconductor encapsulation, wherein the amount is 0.2% by weight or less.

Hereinafter, the present invention will be described in more detail. As the liquid epoxy resin of the component (A) used in the present invention, any one can be used as long as it has two or more epoxy groups in one molecule. In particular, bisphenol A epoxy resin and bisphenol F epoxy resin can be used. Examples include bisphenol-type epoxy resins such as resins, phenol novolak-type epoxy resins, novolak-type epoxy resins such as cresol-novolak-type epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins, and cyclopentadiene-type epoxy resins. Among them, an epoxy resin which is liquid at room temperature is used, and bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin are particularly desirable. There is no problem even if an epoxy resin having the following structure is added to these epoxy resins within a range that does not affect the infiltration property.

[0009]

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The total chlorine content in the liquid epoxy resin is 1,500 ppm or less, preferably 1,000 pp
m or less. 50% at 100 ° C
Extraction water chlorine in 20 hours at epoxy resin concentration is 1
It is preferably at most 0 ppm. If the total chlorine content exceeds 1,500 ppm and the amount of extracted water chlorine exceeds 10 ppm, the reliability of the semiconductor element, particularly, the moisture resistance may be adversely affected.

In the present invention, various inorganic fillers conventionally known are added for the purpose of reducing the expansion coefficient. As the inorganic filler, fused silica, crystalline silica,
Alumina, boron nitride, aluminum nitride, silicon nitride, magnesia, magnesium silicate and the like are used. The sealing material in the underfill portion has an average particle size of about 1/1 with respect to the flip chip gap width (gap between the substrate and the chip) in order to achieve both improved penetration and low linear expansion.
It is preferable to use a filler having a maximum particle size of 0 or less and a maximum particle size of 1/2 or less. The compounding amount is 100 to 400 parts by weight with respect to 100 parts by weight of the total amount of the epoxy resin and the curing agent, preferably 150 to 250 parts by weight with respect to 100 parts by weight of the total amount of the epoxy resin and the curing agent. It is preferable to mix in the range. If it is less than 100 parts by weight, the expansion coefficient is large,
Cracks may be induced in the thermal test. If the amount exceeds 400 parts by weight, the viscosity becomes high, and there is a possibility that the penetration of the thin film is reduced.

In the present invention, the inorganic filler has a water content of 500 ppm or less (that is, 0 to 500 pp).
m), especially 300 ppm or less (that is, 0 to 300 pp)
m) is used. That is, as described later, the present invention uses an acid anhydride-based curing agent as a curing agent.However, if the amount of water in the inorganic filler is large, this water causes the acid anhydride to be hardened. -CO-O-CO- group to -CO
Since the OH group is induced to increase the compound having a carboxyl group derived from this acid anhydride in the epoxy resin composition, the water content of the inorganic filler is 5%.
It is necessary to control it to 00 ppm or less.

In the present invention, an acid anhydride is used as a curing agent. Examples of the acid anhydride include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhymic anhydride, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, 3, 3 ', 4,
4′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride,
Preferably, one molecule of an aliphatic or aromatic ring such as bis (3,4-dicarboxyphenyl) methane dianhydride or 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride is present in the molecule. An acid anhydride having one or two and one or two acid anhydride groups and having 4 to 25, preferably about 8 to 20 carbon atoms is suitable.

In this case, the content of the compound having a carboxyl group (COOH group) is 0.5% by weight or less (ie, 0 to 0.5% by weight), particularly 0.4% by weight or less as the acid anhydride. (That is, 0 to 0.4% by weight) is used.
If the carboxyl group content is more than 0.5% by weight, crystallization may occur, which is not preferable. In this case, the content of the carboxyl group (COOH group) is 0.3% by weight or less (that is, 0 to 0.3% by weight), particularly 0.25% by weight or less (0% by weight) based on the acid anhydride curing agent. ~ 0.25% by weight)
Are preferred for similar reasons.

The compounding amount of the acid anhydride is preferably such that the ratio of the acid anhydride group in the curing agent to the mol of epoxy group in the epoxy resin is in the range of 0.3 to 0.7 mol. .
If it is less than 0.3 mol, the curability is insufficient, and if it exceeds 0.7 mol, unreacted acid anhydride remains and the glass transition temperature may be lowered. More preferably 0.4 to
It is in the range of 0.6 mole.

As the curing agent, carboxylic acid hydrazides such as dicyandiamide, adipic hydrazide and isophthalic hydrazide can be used in addition to the above.

Further, if necessary, the composition of the present invention comprises:
One or two or more selected from imidazole derivatives, tertiary amine compounds, and organic phosphorus compounds can be blended. Here, as the imidazole derivative, 2-methylimidazole, 2-ethylimidazole, 4-methylimidazole, 4-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-hydroxymethyl Imidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 2-phenyl-4-
Methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole and the like can be mentioned. Examples of the tertiary amine compound include amine compounds having an alkyl group or an aralkyl group as a substituent bonded to a nitrogen atom, such as triethylamine, benzyltrimethylamine, and α-methylbenzyldimethylamine.
1,8-diazabicyclo [5.4.0] undecene-7
And a salt thereof with a cycloamidine compound such as a phenol salt, an octylate salt or an oleate salt, or an organic acid thereof, or a salt or a complex salt of a cycloamidine compound such as a compound of the following formula with a quaternary boron compound.

[0018]

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Examples of the organic phosphorus compounds include triorganophosphine compounds such as triphenylphosphine and quaternary phosphonium salts such as tetraphenylphosphonium tetraphenylborate.

The compounding amount is 0.01 to 10 parts by weight based on 100 parts by weight of the total of the epoxy resin and the curing agent.
Desirably, it is 0.5 to 5 parts by weight. If the amount is less than 0.01 part by weight, the curability is reduced. If the amount is more than 10 parts by weight, the curability is excellent, but the storage stability tends to be reduced.

The composition of the present invention may contain a thermoplastic resin such as silicone rubber, silicone oil, liquid polybutadiene rubber, or methyl methacrylate-butadiene-styrene copolymer for the purpose of reducing stress. Preferably, the alkenyl group of the alkenyl group-containing epoxy resin or phenol resin and the number of silicon atoms in one molecule represented by the following formula (1) are 20 to 400, preferably 40 to 200, and a SiH group (that is, It is preferable to blend a copolymer obtained by an addition reaction of an organohydrogenpolysiloxane having 1 to 5 hydrogen atoms bonded to silicon atoms with SiH groups. H _a R _b SiO _{(4-ab) / 2} (1) (wherein, R is a substituted or unsubstituted monovalent hydrocarbon group, a is 0.005 to 0.1, b is 1.8 to 2. 2, 1.81 ≦
It indicates a positive number satisfying a + b ≦ 2.3. )

The monovalent hydrocarbon group of R preferably has 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms.
Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, hexyl group, cyclohexyl group, octyl group, alkyl group such as decyl group, vinyl group, allyl group, propenyl group, butenyl group, hexenyl group Alkenyl groups such as phenyl group, xylyl group, and tolyl group; aralkyl groups such as benzyl group, phenylethyl group, and phenylpropyl group; and a part or all of hydrogen atoms of these hydrocarbon groups. A chloromethyl group substituted by a halogen atom such as fluorine, bromine,
Examples thereof include a halogen-substituted monovalent hydrocarbon group such as a bromoethyl group and a trifluoropropyl group. Among the above copolymers, those having the following structures are particularly desirable.

[0023]

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[0024]

Embedded image(Wherein R is the same as above, R¹¹Is a hydrogen atom or carbon
An alkyl group of the formulas 1-4, R¹²Is -CH_TwoCH_TwoCH_Two−,
-OCH_Two-CH (OH) -CH_Two-O-CH_TwoCH _TwoCH
_Two-Or -O-CH_TwoCH_TwoCH_Two-. n is 4 to 19
9, preferably an integer of 19 to 99, and p is an integer of 1 to 10.
The number and q are integers of 1 to 10. )

The above copolymer is blended so that the diorganopolysiloxane unit is contained in an amount of 0 to 20 parts by weight, particularly 2 to 15 parts by weight, based on 100 parts by weight of the total amount of the liquid epoxy resin and the curing agent. , The stress can be further reduced.

The liquid epoxy resin composition of the present invention may further contain, if necessary, a pigment such as a carbon-functional silane for improving adhesion, a carbon black or the like, a dye, an antioxidant, and other additives.

The epoxy resin composition of the present invention is, for example,
It can be manufactured by stirring, dissolving, mixing, and dispersing an epoxy resin, a silane coupling agent, a curing accelerator, an inorganic filler, and a curing agent, if necessary, simultaneously or separately while applying a heat treatment as needed. A device for mixing, stirring, and dispersing the mixture is not particularly limited, but a raikai machine equipped with a stirring and heating device, three rolls,
A ball mill, a planetary mixer or the like can be used. These devices may be used in appropriate combination.

The liquid epoxy resin composition of the present invention is used for encapsulating a semiconductor device as a potting material, a coating material and the like, and is particularly suitably used as an underfill material for a flip-chip type semiconductor device.

Here, the composition of the present invention comprises a carboxyl group (COO) derived from the above-mentioned acid anhydride contained therein.
The content of the compound having an (H group) is 0.2% by weight or less (that is, 0 to 0.2% by weight), particularly 0.15% by weight or less (that is, 0 to 0.15% by weight). is necessary. When the content of the compound having a carboxyl group exceeds 0.2% by weight, peeling and cracking are likely to occur. in this case,
The content of the carboxyl group (COOH group) is 0.15% by weight or less (that is, 0 to 0.15% by weight), particularly 0.1% by weight or less (0 to 0.1% by weight) based on the whole composition. ) Is preferable for the same reason.

In a flip chip type semiconductor device, for example, in a flip chip type semiconductor device, if the substrate is cured after penetration between the substrate and the chip, it occurs on the silicon nitride coated chip side. In this case, there are various possible causes, but the inhibition of the reaction of the compound having a carboxyl group derived from the acid anhydride contained in the acid anhydride as the curing agent causes the adhesion to the silicon nitride and the composition itself. In any case, the peeling phenomenon can be effectively prevented by limiting the amount of the compound having a carboxyl group in the composition to 0.2% by weight or less as described above. .

The viscosity of the liquid epoxy resin composition of the present invention is preferably not more than 10,000 poise at 25 ° C.

The molding method and molding conditions for encapsulating a semiconductor using the composition of the present invention can be conventional methods. Particularly, as the underfill material, the resin composition is introduced into the voids of the device. Temperature conditions for sealing are 60 to 12
0 ° C., more preferably 70 to 10 ° C.
0 ° C. If the temperature is lower than 60 ° C., the viscosity of the composition is high, so that the gap between the substrate and the chip cannot be penetrated,
On the other hand, when the temperature exceeds 120 ° C., a reaction occurs, which may also hinder penetration. In addition, the molding and curing conditions after the resin composition is intruded and sealed are 0.5 to 150 ° C.
About two hours are preferable.

[0033]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Examples and Comparative Examples 22.5 parts by weight of a bisphenol A type epoxy resin (RE310: manufactured by Nippon Kayaku Co., Ltd.) as a liquid epoxy resin and an acid anhydride (methyltetrahydrophthalic anhydride, MH700) as a curing agent: 11.0 parts by weight of fused silica (PLV7)
-1-1: 60.0 parts by weight of Tatsumori Co., Ltd., 0.5 parts by weight of a silane coupling agent (γ-glycidoxypropyltrimethoxysilane, KBM403: Shin-Etsu Chemical Co., Ltd.), and a curing accelerator (UCAT5002: manufactured by Asahi Kasei Corporation) was mixed in an amount of 6.0 parts by weight and uniformly kneaded to obtain an epoxy resin composition.

In this case, silica having a water content shown in Table 1 was used as silica, and acid anhydride containing a compound having a carboxyl group in an amount shown in Table 1 was used. The content of the compound having a carboxyl group derived from the above acid anhydride in the composition is as shown in Table 1.

Next, the obtained epoxy resin composition was
Dispensing was performed at 100 ° C. on a device mounted on a substrate having a gap of 100 μm with respect to a chip having a size of square mm at 100 ° C., followed by curing at a temperature rising of 7 ° C./min and holding at 150 ° C. × 2 hours. The peeling of the cured product was evaluated. Peeling was checked with a commercially available ultrasonic flaw detector. The results are also shown in Table 1.

[0037]

[Table 1] * The number of chips is 20, and the ratio of the peeled area is (total (%) of peeled area to total area of chip / 20).

[0038]

The liquid epoxy resin composition for encapsulating a semiconductor of the present invention can prevent peeling and cracking,
It is highly reliable.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Toshio Shiohara 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture F-term in the Silicon Electronics Research Laboratory, Shin-Etsu Chemical Co., Ltd. (Reference) 4J002 CD021 CD041 CD051 CD061 DE076 DE146 DF016 DJ006 DJ 016

Claims (2)

[Claims] 1. A liquid epoxy resin composition comprising (A) a liquid epoxy resin, (B) an inorganic filler, and (C) an acid anhydride-based curing agent as essential components, wherein the inorganic filler has a water content of 500 ppm. The amount of the compound having a carboxyl group contained in the acid anhydride is 0.5% by weight or less.
A liquid epoxy resin composition for semiconductor encapsulation, wherein the amount of a compound having a carboxyl group from the acid anhydride contained in the composition is 0.2% by weight or less. 2. The composition according to claim 1, which is used for an underfill material of a flip-chip type semiconductor device.