JP2000198831A - Epoxy resin composition and sealing of lsi using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition causing suppressed foaming at high temperature and useful as a resin composition for LSI sealing by using a specific acid anhydride as a curing agent and a specific cure accelerator. SOLUTION: The objective composition contains (A) an epoxy resin (e.g. naphthalene-type epoxy resin), (B) one or more kinds of acid anhydrides selected from an acid anhydride expressed by formula (R1 to R3 are each H or a 1-6C hydrocarbon group), an acid anhydride of formula wherein the carbon-carbon double bond in the anhydride is hydrogenated and pyromellitic anhydride, (C) a latent cure accelerator (e.g. an adduct of an imidazole compound and an epoxy resin) and preferably further (D) a filler (e.g. fused silica). Preferably, the amount of the component B is 0.8-1.1 equivalent based on 1 equivalent of epoxy group of the component A, the active component of the component C is 2-15 pts.wt. based on 100 pts.wt. of the component A and the amount of the component D is 30-65% of the total composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin composition, an LSI sealing resin composition comprising the epoxy resin composition, and a method for sealing an LSI using the LSI sealing resin composition.

[0002]

2. Description of the Related Art Epoxy resin compositions are used in various applications such as sealants and adhesives for electronic parts. Above all, those having a certain level of storage stability and being liquid (including paste) are frequently used in semiconductor products such as LSIs because of their easy handling (high workability). In these fields, it is preferable to heat and cure the encapsulant in as short a time as possible from the viewpoint of reducing the production cost of the product by improving the productivity.

[0003] Means for increasing the curing rate of the epoxy resin composition include a method of increasing the reactivity of the epoxy resin composition and a method of increasing the heating temperature.

[0004] As a method, for example, a method of using an imidazole compound as a curing agent for an epoxy resin and increasing the amount of addition is cited. When an imidazole compound is used in an increased amount, the curing agent is used as a curing agent. There is a problem that the viscosity is higher than in the case where another curing agent such as an acid anhydride compound is used, and the workability is reduced.

As a method of (1), there is a method in which the heating temperature is raised to a high temperature, for example, 200 ° C. or higher. However, such a method has problems such as foaming of the composition at the time of curing and deterioration of physical properties of the cured product. .

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have used a specific acid anhydride as a curing agent for an epoxy resin and a specific curing accelerator. It has been found that foaming at a high temperature of 200 ° C. or higher can be suppressed by using, and the present invention has been completed.

That is, the present invention provides (A) an epoxy resin, (B) a general formula (1):

[0008]

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[0009] ^{(wherein, R 1, R 2, R} 3 each represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, R ^1,
R ² and R ³ may be the same or different, provided that
At least one of R ¹ , R ² and R ³ is not a hydrogen atom), or an acid anhydride represented by the general formula (1) wherein a carbon-carbon double bond is hydrogenated. An epoxy resin composition comprising at least one of anhydrides and pyromellitic anhydrides, and (C) a latent curing accelerator (Claim 1), and further comprising a filler.
The epoxy resin composition described in claim 2 (claim 2), the resin composition for sealing LSI using the epoxy resin composition described in claim 1 or 2, and the resin composition for LSI sealing described in claim 3. The present invention relates to a method (claim 4) for sealing an LSI by using a material and pressing at a high temperature for a short time.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the epoxy resin composition of the present invention, an epoxy resin as component (A) (hereinafter also referred to as epoxy resin (A)) is used as a main component.

The epoxy resin (A) can be used without particular limitation as long as it is generally used for a liquid (including paste-like) epoxy resin composition, and the number of epoxy groups contained in a molecule is not limited. Are preferred because they are suitable for suppressing foaming at a high temperature of 200 ° C. or higher and can form a crosslinked structure capable of exhibiting sufficient heat resistance. Further, four or less, and more preferably three or less are preferable in that a low-viscosity resin composition can be obtained. If the number of epoxy groups contained in the molecule is too small, the heat resistance of the cured product decreases,
If the strength is too high, the viscosity tends to be high, and the curing shrinkage tends to be high.

The number average molecular weight of the epoxy resin (A) is 2
20-700 and 280-500 are 2
It is suitable for suppressing foaming at a high temperature of 00 ° C. or higher, is preferable in that a low-viscosity composition can be obtained, and the balance of physical properties is good. If the number average molecular weight is too small, it becomes difficult to suppress foaming at high temperature, the strength of the cured product becomes weak, and the tendency that moisture resistance becomes low tends to occur.If it is too large, the viscosity of the composition becomes high. Tend to occur.

Specific examples of the epoxy resin (A) include, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, glycidylamine type epoxy resin, and fat. Cyclic epoxy resin, dicyclopentadiene type epoxy resin, novolak type epoxy resin, polyether modified epoxy resin,
Copolymers with other polymers such as silicone-modified epoxy resins, rubber particle-dispersed epoxy resins, diaryl sulfide-type epoxy resins, diaryl ether-type epoxy resins, and the like. These may be used alone or in combination of two or more. Among these, naphthalene type epoxy resin, bisphenol A
Type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin and the like are preferable from the viewpoint of relatively low viscosity, excellent heat resistance and moisture resistance. Especially, naphthalene type epoxy resin,
It is preferred because it has high reactivity and is excellent in short-time curability.

Part of the epoxy resin (A) may be replaced with an epoxy-based reactive diluent as long as the effects of the present invention are not impaired.

Examples of the epoxy reactive diluent include resorcin diglycidyl ether, tert-butylphenyl glycidyl ether and cyclohexane dimethanol diglycidyl ether (molecular weight: 254):

[0016]

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And the like. These may be used alone or in combination of two or more. Of these, cyclohexanedimethanol diglycidyl ether is preferred from the viewpoints of a large dilution effect and a relatively large molecular weight.

If the epoxy-based reactive diluent is used in a large amount, it is difficult to suppress foaming at 200 ° C. or higher, and the cured product tends to deteriorate in moisture resistance and heat resistance. ) Is preferably not more than 20% by weight (hereinafter referred to as%), more preferably not more than 10%.
In addition, in order to obtain the effect by using, it is preferable that the content is 1% or more, more preferably 5% or more.

The epoxy resin composition of the present invention has a general formula (1) as component (B) as a curing agent for the epoxy resin:

[0020]

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(Wherein R ¹ , R ² and R ³ each represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms;
R ¹ , R ² and R ³ may be the same or different, provided that at least one of R ¹ , R ² and R ³ is not a hydrogen atom); An acid anhydride and a pyromellitic anhydride (hereinafter also referred to as an acid anhydride (B)) in which a carbon-carbon double bond in the acid anhydride is hydrogenated are used.

The acid anhydride (B) has a low vapor pressure,
A composition that does not easily foam even at a high temperature of 00 ° C. or higher can be obtained, and a composition that gives a cured product having high heat resistance can be obtained.

Among the acid anhydrides (B), acid anhydrides represented by the general formula (1) (hereinafter referred to as acid anhydrides) are preferable because they are liquid, have good storage stability, and have low water absorption. Product (1)) and an acid anhydride represented by the general formula (1) in which a carbon-carbon double bond is hydrogenated (hereinafter also referred to as hydrogenated anhydride (1)) Is preferred,
Further, hydrogenated anhydride (1) is preferable because the transparency of the cured product is improved.

Acid anhydride (1) and hydrogenated anhydride (1)
Has a molecular weight of from 208 to 376, further from 222 to 3 from the viewpoints of low viscosity, high heat resistance, low vapor pressure, and imparting hydrophobicity.
08 is preferred. The molecular weight is determined so as to achieve a good balance between low viscosity and high heat resistance, which is preferably low, and low vapor pressure and hydrophobicity, which are preferably high.

R ¹ , R ² and R ³ in the general formula (1) are
From the viewpoint of the molecular weight, a hydrogen atom or carbon number 1
To 6 hydrocarbon groups. Provided that R ¹ , R ² and R ³
Preferably, at least one of is not a hydrogen atom,
The total number of carbon atoms of R ¹ , R ² and R ³ is preferably ³ to 15, more preferably 4 to 10, and particularly preferably 6.

Preferred specific examples of the acid anhydride (1) include, for example,

[0027]

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And the like. Preferred specific examples of the hydrogenated anhydride (1) include compounds obtained by hydrogenating two carbon-carbon double bonds in the preferred specific examples of the acid anhydride (1).

The amount of the acid anhydride (B) used is 0.8 to 1.1 equivalents of the acid anhydride (B) per 1 equivalent of the epoxy group of the epoxy resin (A), and more preferably 0.9 to 1. It is preferably 0 equivalent. When the amount of the acid anhydride (B) is less than 0.8 equivalent, the heat resistance tends to decrease due to a decrease in the crosslinking density, and when the amount exceeds 1.1 equivalent, the acid anhydride remains excessively and the moisture resistance becomes poor. The tendency to decrease tends to occur.

The epoxy resin composition of the present invention comprises (C)
A latent curing accelerator (hereinafter also referred to as an accelerator (C)) as a component is contained.

The accelerator (C) is a component for accelerating the curing reaction between the epoxy resin (A) and the acid anhydride (B) at 120 to 250 ° C., and has an accelerating effect at 80 ° C. or lower, further at 40 ° C. or lower. And a stable epoxy resin composition can be obtained. Further, since the accelerator (C) is used as a curing accelerator for the epoxy resin composition of the present invention, the curing is completed in a very short time at a high temperature.

The accelerator (C) can be used without any particular limitation as long as it is generally used for an epoxy resin composition. In particular, those used as an accelerator for a one-pack type epoxy resin composition can be used. Is preferred.

Specific examples of the accelerator (C) that can be used in the one-pack type epoxy resin composition include, for example, Novacure HX3088 (trade name) comprising an adduct of an imidazole compound and an epoxy resin (Asahi Chiba Corporation) Novacure HX3921HP (trade name) (made by Asahi Ciba Co., Ltd.),
NOVACURE HX3941HP (trade name) (Asahi Chiba Co., Ltd.)
Amicure MY24 (trade name) (Ajinomoto Co., Ltd.)
TQ, an imidazole-based microgel-type accelerator
530 (manufactured by Ciba Specialty Chemicals). These may be used alone or in combination of two or more. Among these, Novacur HX308 is used from the viewpoint of compatibility between storage stability and rapid curing.
8, Novacure HX3941HP and the like are preferable.

The amount of the accelerator (C) used is based on 100 parts of the epoxy resin (A) and the amount of the active ingredient (for example, in the case of an accelerator in which the active ingredient such as imidazole is dispersed in a resin or microgel, And 2 to 15 parts, and more preferably 3 to 10 parts. Use of more than 15 parts does not improve the accelerating effect, but rather tends to cause undesirable tendencies such as poor storage stability. If the amount is less than 2 parts, the sufficient accelerating effect may not be obtained. Is more likely to occur.

The viscosity of the epoxy resin composition comprising the epoxy resin (A), the acid anhydride (B) and the accelerator (C) is as follows:
Although it depends on the type of the epoxy resin and the acid anhydride (B) to be used, it may be in the range conventionally used.

The epoxy resin composition contains, in order to reduce the coefficient of thermal expansion of the cured product and to increase the strength,
Further, a filler can be contained.

As the filler, any filler that is generally used in an epoxy resin composition can be used without particular limitation.

Specific examples of the filler include fused silica powder, quartz glass powder, crystalline silica powder, glass fiber, alumina powder, and talc. These may be used alone or in combination of two or more.

When the filler is used, the amount of the filler used is preferably as large as possible when, for example, obtaining a resin composition for LSI encapsulation. Is 45-55%.

Further, the epoxy resin composition of the present invention includes:
If necessary, additives such as various coupling agents, defoaming agents, leveling agents, low-stressing agents, and pigments can also be blended.

Since the epoxy resin composition is a composition containing an acid anhydride (B) as a curing agent and an accelerator (C) as a curing accelerator, foaming at a high temperature of 200 ° C. or more is performed. It is a liquid composition which can be cured in a short time, and can be suitably used as it is or by adding a filler or the like as a resin composition for LSI encapsulation. Among them, from the viewpoint of reducing the production cost of products by improving productivity, a composition capable of suppressing foaming and curing in a short time is particularly suitable for a mounting method such as a flip chip in which a strong demand is particularly strong. Can be used.

Hereinafter, the case where the epoxy resin composition of the present invention is used for encapsulating an LSI will be described by taking flip chip mounting as an example. However, the epoxy resin composition of the present invention is also used for mounting other than flip chips. It goes without saying that you can do it.

An LSI using the epoxy resin composition of the present invention
In the method of sealing the LSI, the LSI is sealed by pressure contact at a high temperature for a short time. Therefore, productivity is increased and cost can be reduced.

In flip-chip mounting, a solder joint is provided at a terminal of a silicon chip having a terminal on the side where a circuit is formed, and the terminal on the substrate is joined to the joint. And the circuit are sealed with the LSI sealing resin composition.

First, an appropriate amount of the sealing resin composition is applied to the terminal side surface of the substrate by printing, dispensing from a nozzle, or the like. The appropriate amount depends on the size of the LSI to be sealed and the like, but may be the minimum amount that can completely seal the portion requiring sealing with the sealing resin composition.

The above-mentioned pressing at a high temperature and in a short time means that the surface on which the sealing resin is applied and the surface to be bonded (joined) are brought into contact with each other while keeping them parallel to each other.
While heating to a high temperature of 150 to 300 ° C., further 180 to 250 ° C., particularly 220 to 250 ° C. at a pressure of ^{20 to} 100 kg / cm ² , more preferably 1 to 10
It means that curing is achieved in seconds, and further in 2 to 5 seconds. At this time, the solder may be melted at the same time to complete the mounting.

The heating method is not particularly limited, and a generally used heating method may be used. For example, heating may be performed by a pressurizable heater tool.

[0048]

EXAMPLES Next, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

The raw materials and evaluation methods used in the following Examples and Comparative Examples are summarized below.

(Epoxy resin) RE310S: Bisphenol A type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) EPC830LVP: Bisphenol F type epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc.) (acid anhydride) YH306: acid anhydride Product (1) (manufactured by Yuka Shell Epoxy Co., Ltd.).

YH307: acid anhydride (1) (manufactured by Yuka Shell Epoxy).

PMDA: pyromellitic dianhydride

EPC B4400: 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (manufactured by Dainippon Ink and Chemicals, Inc.).

HN5500: methyl hexahydrophthalic anhydride (manufactured by Hitachi Chemical Co., Ltd.).

MHAC-P: methylhymic anhydride (manufactured by Hitachi Chemical Co., Ltd.).

(Latent curing accelerator) HX3088: Microcapsule type imidazole-based curing accelerator, active ingredient 33% (Novacure HX3088 manufactured by Asahi Ciba Co., Ltd.).

HX3921HP: Microcapsule type imidazole-based curing accelerator, active ingredient 33% (Novacure HX3921HP manufactured by Asahi Ciba Co., Ltd.).

HX3941HP: Microcapsule type imidazole-based curing accelerator, active ingredient 33% (Novacure HX3941HP manufactured by Asahi Ciba Co., Ltd.).

PN23: imidazole adduct latent curing agent, active ingredient 100% (Ajinomoto Co., Inc.)
Made).

(Expandability) About 10 mg of the prescribed composition is weighed on a transparent glass plate (15 mm × 15 mm), the resin side is brought into contact with a hot plate heated to a prescribed temperature, and the composition is visually passed through the glass. Observe the condition of the object and check for the presence or absence of foaming.
And

(Curing time) When the foaming property is evaluated, the time until the glass plate is fixed to the hot plate is measured.

Examples 1 to 5 and Comparative Examples 1 to 7 The raw materials shown in Table 1 were blended so that the compositions shown in Table 1 were obtained.
The mixture was uniformly mixed with a stirrer. After sufficiently defoaming (10 minutes) the obtained compositions under vacuum (1 to 10 mmHg), the foaming property and the curing time were evaluated.

Table 2 shows the results.

[0064]

[Table 1]

[0065]

[Table 2]

[0066]

According to the present invention, an epoxy resin composition capable of increasing the reaction rate by suppressing foaming at a high temperature of 200 ° C. or higher can be obtained. For this reason, a non-foamed cured product can be obtained in a short time at a high temperature of 200 ° C. or higher, which was impossible in the past, and is suitable as a resin composition for LSI sealing, particularly for LSI sealing by high-temperature pressure welding. .

Continued on the front page F term (reference) 4J002 CD001 CD022 EL136 FD018 FD146 FD157 GQ00 4J036 AA01 AB07 AB09 DA10 DB20 DB21 FA01 HA12 JA07 4M109 AA01 BA04 CA05 CA12 EA02 EA06 EB02 EB04 EB06 EB07 EB08 EC05 EB19 EC05

Claims (4)

[Claims] (A) an epoxy resin, (B) a general formula (1): (In the formula, R ¹ , R ² , and R ³ each represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and R ¹ , R ² , and R ³ may be the same or different; ¹ , R ² and R ³
At least one of which is not a hydrogen atom), a carbon in the acid anhydride represented by the general formula (1)
An epoxy resin composition comprising one or more of an acid anhydride and a pyromellitic anhydride in which a carbon double bond is hydrogenated and (C) a latent curing accelerator. 2. The epoxy resin composition according to claim 1, further comprising a filler. 3. An LSI sealing resin composition comprising the epoxy resin composition according to claim 1. 4. A method for sealing an LSI by using the resin composition for sealing an LSI according to claim 3 by high-temperature and short-time pressure welding.