JP2000281878A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for transfer molding excellent in filling properties in gaps between a semiconductor element and a substrate, moisture resistance reliability and solder reflow crack resistance in a semiconductor device of a flip chip packaging system. SOLUTION: The characteristic of this composition is an epoxy resin composition consisting essentially of solid epoxy resin, a solid phenol resin, a spherical inorganic filler and a curing accelerator having <=24 μm maximum grain diameter and 0.1-15 μm average grain diameter of the spherical inorganic filler and containing the spherical inorganic filler in an amount of 70-93 wt.% in the whole epoxy resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip-chip mounting type semiconductor device for transfer encapsulation which has a good filling property in a gap between a semiconductor element and a substrate, and has excellent solder reflow resistance and moisture resistance reliability. Epoxy resin composition,
And a semiconductor device using the same.

[0002]

2. Description of the Related Art In recent market trends of miniaturization, weight reduction and high performance of electronic devices, LSs mounted on cellular phones have been developed.
In I, the CSP (chip
sizepackage) Implementation has begun to spread. Semiconductor element size mounting is a technology that can reduce the mounting area of an LSI to element dimensions, and includes bare chip mounting and CSP mounting. CSP implementations have received particular attention because of their ease of handling. Various structures of the CSP have been proposed and put into practical use, depending on the built-in substrate, the method of connecting the semiconductor elements, and the like. The CSP sealing method includes potting with a liquid sealing resin, collective sealing by transfer molding, application of a liquid underfill material, and the like. Among these, in a flip-chip mounting type semiconductor device, a gap between a semiconductor element and a substrate is sealed with a liquid resin called filling and filling type underfill. The liquid underfill material is composed of a thermosetting resin and a filler, and flows through gaps between a semiconductor element, a substrate, and connection terminals (bumps) of a semiconductor device by utilizing a capillary phenomenon or the like. The productivity of this type of semiconductor device depends on the filling rate of the underfill, and it is necessary to fill the underfill quickly to improve the production efficiency, but the fast filling causes unfilling and voids. Since the reliability of the semiconductor device is easily reduced, it is difficult to dramatically improve the productivity of the semiconductor device. In addition, the conventional liquid underfill material has a low filling amount of the inorganic filler and a large amount of resin component, so that it is easy to absorb moisture, and the flip-chip type semiconductor device using the underfill is smaller than a plastic package such as TSOP or TQFP. However, they are inferior in moisture resistance reliability, low in solder reflow crack resistance, and have technical problems for widespread use. From such a problem, an underfill epoxy resin composition (hereinafter referred to as a resin composition) having excellent filling properties into a gap between a semiconductor element and a substrate, excellent productivity, and excellent moisture resistance reliability and solder reflow crack resistance. ) Development is desired.

[0003]

DISCLOSURE OF THE INVENTION The present invention is directed to a flip chip mounting method which has a good filling property in a gap between a semiconductor element and a substrate, such as a lead frame and a plastic substrate, as well as solder reflow resistance and moisture resistance reliability. And a semiconductor device using the same.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an epoxy resin composition comprising a solid epoxy resin, a solid phenol resin, a spherical inorganic filler and a curing accelerator as essential components. Is 24 μm or less, more preferably the maximum particle diameter of the spherical inorganic filler is 12 μm
An epoxy resin composition for semiconductor encapsulation for transfer encapsulation, wherein the average particle diameter is 0.1 to 15 μm and the spherical inorganic filler is 70 to 93% by weight in the total epoxy resin composition. And a semiconductor device obtained by sealing a semiconductor element using the same.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The epoxy resin used in the present invention is an epoxy resin which is a solid at room temperature and includes all monomers, oligomers and polymers having two or more epoxy groups in one molecule. For example, biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, triphenol nomethane type epoxy resin, alkyl-modified triphenol methane type epoxy resin and epoxy containing triazine nucleus Resins. When an epoxy resin that is liquid at room temperature is used, the storage stability of the resin composition is reduced, and it becomes difficult to handle, and it is particularly difficult to make a tablet. As the phenolic resin used in the present invention, a phenolic resin which is solid at normal temperature, a monomer having two or more phenolic hydroxyl groups in one molecule,
Refers to oligomers and polymers in general. For example, phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol resin, phenol aralkyl resin, terpene-modified phenol resin, triphenolmethane-type resin, etc. Resins, terpene-modified phenolic resins and mixtures thereof are preferred. When a phenol resin that is liquid at normal temperature is used, the storage stability of the resin composition is reduced, and it is difficult to handle, particularly, it is extremely difficult to make a tablet.

The curing accelerator used in the present invention may be any one which promotes the curing reaction between the epoxy resin and the phenolic resin, and those generally used for a sealing material can be widely used. . For example, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, dimethylbenzylamine, 2-methylimidazole and the like can be mentioned, and these may be used alone or as a mixture. As the kind of the spherical inorganic filler used in the present invention, those generally used for a sealing material can be widely used. Examples of the inorganic filler include fused silica powder, crystalline silica powder, alumina powder, silicon nitride powder, and aluminum nitride powder. Spherical fused silica is more preferable as the spherical inorganic filler because of its versatility. The maximum particle size of the spherical inorganic filler of the present invention is 24 μm or less, more preferably 12 μm or less. If it exceeds 24 μm, 3
It is impossible to fill a gap smaller than about 0 μm, and the underfill function does not appear. The filling amount of the spherical inorganic filler is preferably 70 to 93% by weight of the whole resin composition. If it is less than 70% by weight, the solder reflow crack resistance is low. It is also difficult to fill the gap in the substrate. The average particle diameter is preferably from 0.1 to 15.0 μm, more preferably from 0.1 to 10 μm. Less than 0.1 μm or 1
If it exceeds 5 μm, the fluidity is reduced and it is difficult to fill the gap between the element and the substrate.

The resin composition of the present invention comprises a solid epoxy resin, a solid phenol resin, a spherical inorganic filler, and a curing accelerator as essential components. In addition, if necessary, a brominated epoxy resin, an antimony oxide And the like, a flame retardant such as, a coupling agent, a coloring agent represented by carbon black, a release agent such as a natural wax and a synthetic wax, and the like can be appropriately compounded. In order to obtain a resin composition, the components are mixed, heated and kneaded with a heating kneader or a hot roll, and then cooled and pulverized to obtain a desired resin composition. In order to manufacture a semiconductor device using the resin composition of the present invention, a substrate on which a chip is mounted is set in a mold via connection terminals (bumps), and is placed in a mold having a mold temperature of 100 ° C. or higher. By performing low-pressure transfer molding, the intended semiconductor device can be obtained by resin sealing.

[0008]

The present invention will be specifically described below with reference to examples. Example 1 Biphenyl type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., melting point: 95 ° C., epoxy equivalent: 190) 7.2 parts by weight Phenol aralkyl resin (manufactured by Mitsui Chemicals, Inc., softening point: 65 ° C., hydroxyl group) Equivalent 175) 7.5 parts by weight Brominated epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent 365, softening point 55 ° C) 2.0 parts by weight 1,8-diazabicyclo (5,4,0) ) Undecene-7 (hereinafter referred to as DBU) 0.18 parts by weight Carbon black 0.3 parts by weight Carnauba wax 0.4 parts by weight Aminosilane coupling agent 0.4 parts by weight Spherical silica A (average particle diameter 4.2 μm, maximum) 80 parts by weight Antimony oxide 2 parts by weight After all the above components were mixed by a mixer, the surface temperature was adjusted to 3 by using two rolls of 90 ° C and 45 ° C. Turn kneading, the kneaded product sheet obtained by pulverizing after cooling to obtain a resin composition. The properties of the obtained resin composition were evaluated by the following methods. Table 1 shows the evaluation results.

Evaluation method Spiral flow: Using a mold for spiral flow measurement in accordance with EMMI-I-66, a mold temperature of 175 ° C.
The measurement was performed at an injection pressure of 70 kg / cm ² and a curing time of 2 minutes.
Judgment of the fluidity, the spiral flow value is less than 60 ×,
○: 60 or more. Judgment of filling property: れ ば when filling into a 20 μm slit is 60 mm or more, × when less than 60 mm, □ when filling into a 10 μm slit is 60 mm or more. Filling test: Molding at a mold temperature of 175 ° C., 100 kg / cm ² , injection time of 15 seconds, and curing time of 105 seconds using a mold for slit burr measurement (slits having a thickness of 10 μm and 20 μm, a length of 70 mm and a width of 10 mm). Measure the filled distance. Reflow crack resistance test: 9 × under the conditions of 180 ° C., 100 kg / cm ² , and 90 seconds using a low-pressure transfer molding machine.
A 9mm element is 80p of 14 × 20 × 2.0mm size.
A test device sealed in a QFP was heated at 85 ° C and a relative humidity of 60.
% For 168 hours, followed by a peak temperature of 2
It processed by IR reflow set to 40 degreeC and processing time 10 second, and the presence or absence of a crack was confirmed by the ultrasonic flaw detector. Moisture resistance reliability test: 180 with low pressure transfer molding machine
A test element in which a 9 × 9 mm element was sealed in a 14 × 20 × 2.0 mm size 80pQFP under conditions of 100 ° C., 100 kg / cm ² and 90 seconds was treated for 168 hours in an environment of 30 ° C. and 70% relative humidity. After that, IR reflow (maximum 2
A pressure cooker test (125 ° C., 100% humidity) was performed for 500 hours after treating at 40 ° C. for 10 seconds, and circuit failure was measured.

Examples 2 to 4 and Comparative Examples 1 to 6 A resin composition was obtained in the same manner as in Example 1 by blending according to the formulations shown in Tables 1 and 2. This resin composition was evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2. The materials used in Examples 2 to 4 and Comparative Examples 1 to 6 are shown below. Orthocresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., melting point 62 ° C., epoxy equivalent 200),
Phenol novolak resin (softening point 65 ° C., hydroxyl equivalent 104), spherical silica B (average particle diameter 2.9 μm, maximum particle diameter 12 μm), spherical silica C (average particle diameter 6.5 μm)
m, maximum particle diameter 30 μm), spherical silica D (average particle diameter 20 μm, maximum particle diameter 71 μm), spherical silica E (average particle diameter 0.05 μm, maximum particle diameter 24 μm), spherical silica F (average particle diameter 17 μm, maximum Particle size 24 μm).

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

The epoxy resin composition for semiconductor encapsulation of the present invention is excellent in productivity, humidity resistance, and solder reflow crack resistance, and is particularly suitable for a flip-chip mounting type semiconductor device.

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Claims (3)

[Claims] 1. An epoxy resin composition comprising a solid epoxy resin, a solid phenol resin, a spherical inorganic filler, and a curing accelerator as essential components, wherein the spherical inorganic filler has a maximum particle size of 24 μm or less, and an average particle size. 0.1-15μ
m, wherein the spherical inorganic filler accounts for 70 to 93% by weight of the total epoxy resin composition. 2. The spherical inorganic filler has a maximum particle size of 12 μm.
2. The epoxy resin composition for semiconductor encapsulation according to claim 1, which is not more than m. 3. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.