JP2005281581A - Epoxy resin composition and semiconductor device given by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an epoxy resin composition capable of sharply decreasing damage on an element which is caused by stress produced in case of assembling a semiconductor device by using the element having low dielectric characteristics or stress due to reflow heating in case of mounting the element, and to provide the semiconductor device produced by using the same. <P>SOLUTION: This epoxy resin composition for sealing the semiconductor contains (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, and (D) a silica powder as an essential components, wherein the silica powder (D) has an average particle diameter of ≤30 μm, has a content of particles having a particle diameter of ≥150 μm of less than 1 wt% based on an amount of the total silica powder and a content of particles having a particle diameter of ≥75 μm of less than 10 wt% based on the amount of the total silica powder, and a molded product which is given by curing and molding the resin composition has a dispersion value of distribution state of Si elements of ≤70, when an arbitrary section of the molded product is subjected to electron probe micro analysis (EPMA). The semiconductor device is produced by sealing the semiconductor element by using the composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an epoxy resin composition for semiconductor encapsulation excellent in stress characteristics and a semiconductor device using the same.

  Conventionally, many semiconductor devices have been sealed with an epoxy resin composition. In recent years, semiconductor devices have been increased in speed and functionality, and accordingly, more stress is applied to semiconductor elements. An interlayer insulating layer used between wirings of a semiconductor element is required to have low dielectric properties. However, since the interlayer insulating layer having low dielectric properties itself is structurally weak, it starts from the sealing material side. There is a problem in that a failure of resisting stress and structural destruction of the wiring including the interlayer insulating layer occurs, and the function as a semiconductor element cannot be exhibited. In order to prevent damage to the semiconductor element when manufacturing a semiconductor device, a technique of adding a silicone compound that imparts low elasticity to the epoxy resin composition for semiconductor encapsulation (see, for example, Patent Document 1). ) And a method using a resin system constituting a low-crosslinking structure (for example, see Patent Document 2). However, even if these methods are used, it has become difficult to cope with devices having further low dielectric properties.

Japanese Patent No. 2595292 (pages 1 to 4) JP 2002-179773 (pages 2-7)

  The present invention has been made to solve the above-described conventional problems, and the object of the present invention is to generate stress during assembly and reflow during mounting in a semiconductor device using an element having low dielectric characteristics. An epoxy resin composition capable of significantly reducing damage to elements due to stress caused by heating, and a semiconductor device manufactured using the same are provided.

The present invention
[1] (A) epoxy resin, (B) curing agent, (C) curing accelerator, and (D) the average particle size is 30 μm or less, and the content of particles having a particle size of 150 μm or more is 1 in the total silica powder. An epoxy resin composition for encapsulating a semiconductor comprising as an essential component a silica powder that is less than 10% by weight and the content of particles having a particle diameter of 75 μm or more is less than 10% by weight in the total silica powder, and the resin composition An epoxy resin composition characterized in that when EPMA (Electron Probe Micro Analyzer) analysis is performed on an arbitrary cross section of a molded product obtained by curing and molding, a variation value of Si element distribution state is 70 or less,

[2] The silica powder has an average particle size of 25 μm or less, the content of particles having a particle size of 75 μm or more is less than 0.5% by weight in the total silica powder, and contains particles having a particle size of 53 μm or more. The epoxy resin composition according to item [1], wherein the amount is less than 1% by weight of the total silica powder,

[3] The epoxy resin composition according to [1] or [2], wherein a dispersion value of a dispersion state of Si element in the EPMA analysis is 50 or less,

（式中、Ｒ１、Ｒ２は水素又は炭素数１〜４のアルキル基で、互いに同一でも異なっていてもよい。ａは０〜３の整数、ｂは０〜４の整数。ｎは平均値で、１〜５の正数。） [4] The epoxy resin composition according to any one of [1], [2] or [3], wherein the epoxy resin is an epoxy resin represented by the general formula (1),

(In the formula, R1 and R2 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. A is an integer of 0 to 3, b is an integer of 0 to 4. n is an average value. , A positive number from 1 to 5.)

（式中、Ｒ１、Ｒ２は水素又は炭素数１〜４のアルキル基で、互いに同一でも異なっていてもよい。ａは０〜３の整数、ｂは０〜４の整数。ｎは平均値で、１〜５の正数。） [5] The epoxy resin composition according to any one of [1], [2] or [3], wherein the curing agent is a phenol resin represented by the general formula (2).

(In the formula, R1 and R2 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. A is an integer of 0 to 3, b is an integer of 0 to 4. n is an average value. , A positive number from 1 to 5.)

（式中、Ｒ１、Ｒ２は水素又は炭素数１〜４のアルキル基で、互いに同一でも異なっていてもよい。ａは０〜３の整数、ｂは０〜４の整数。ｎは平均値で、１〜５の正数。）

（式中、Ｒ１、Ｒ２は水素又は炭素数１〜４のアルキル基で、互いに同一でも異なっていてもよい。ａは０〜３の整数、ｂは０〜４の整数。ｎは平均値で、１〜５の正数。） [6] The [1], [2] or [3], wherein the epoxy resin is an epoxy resin represented by the general formula (1) and the curing agent is a phenol resin represented by the general formula (2). ] The epoxy resin composition according to any one of items

(In the formula, R1 and R2 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. A is an integer of 0 to 3, b is an integer of 0 to 4. n is an average value. , A positive number from 1 to 5.)

(In the formula, R1 and R2 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. A is an integer of 0 to 3, b is an integer of 0 to 4. n is an average value. , A positive number from 1 to 5.)

[7] A semiconductor device comprising a semiconductor element sealed with the epoxy resin composition according to any one of [1] to [6],
It is.

  According to the present invention, an epoxy resin composition capable of significantly reducing damage to the element due to stress generated during assembly and stress due to reflow heating during mounting in a semiconductor device using an element having low dielectric characteristics, and A semiconductor device manufactured using the same is obtained.

The present invention relates to an epoxy resin for reducing a stress generated when a semiconductor device is assembled in a semiconductor device using a semiconductor element having a low dielectric property, and a stress generated by reflow heating when being surface-mounted on a substrate. Focusing on the dispersibility of the constituent components of the composition, it was made based on the knowledge that the stress applied to the semiconductor element can be suppressed. (A) epoxy resin, (B) curing agent, (C The curing accelerator and (D) the average particle size is 30 μm or less, the content of particles having a particle size of 150 μm or more is less than 1% by weight in the total silica powder, and the content of particles having a particle size of 75 μm or more is An epoxy resin composition for encapsulating a semiconductor comprising silica powder that is less than 10% by weight of the total silica powder as an essential component, and EPMA (Electron P) in an arbitrary cross section of a molded product obtained by curing and molding the resin composition. In the analysis of the robe micro analyzer, it was found that the variation value of the distribution state of the Si element is 70 or less, preferably 50 or less, which is an important factor.
Details regarding the present invention will be described below.

As an EPMA (Electron Probe Micro Analyzer) analyzer used in the present invention, for example, JXA-8600M manufactured by JEOL Ltd. can be mentioned, and the measurement conditions can be as follows, for example.
Acceleration voltage: 15.0kV
Flow current: 5.0 × 10 ^-8
Resolution: 20 μm
Measurement area: 8.0 × 8.0 mm (400 pixels × 400 pixels)
Analysis time: 150ms / pixel
Measuring element: Si
Moreover, the preparation conditions of the molded article of the epoxy resin composition used for the EPMA analysis of the present invention can be as follows, for example.
Molding temperature: 170 ° C
Molding pressure: 2.9 MPa
Molding time: 120 seconds A sample cut out to a size of about 18 mm × 18 mm from a molded product (50 φmm, thickness 3 mm) of the epoxy resin composition obtained under the above conditions was embedded with an epoxy resin embedding agent and observed After polishing and polishing the surface, vapor deposition is performed to obtain an EPMA measurement sample.
In the data analysis, the distribution state of the measured Si element can be treated as the intensity, and the variation degree of the intensity can be calculated as the standard deviation (n number in the above condition is 160000 = 400 × 400). A large standard deviation means less homogeneity of the molding material.

In the present invention, when EPMA analysis is performed on an arbitrary cross section of a molded product obtained by curing and molding the resin composition, it is essential that the variation value of the distribution state of the Si element is 70 or less, more preferably 50. It is as follows. This means that when the intensity variation value representing the distribution state of the Si element exceeds 70, the homogeneity of the molded product is poor, thereby increasing the local stress on the low dielectric element, This leads to destruction of the element itself.
When EPMA analysis is performed on an arbitrary cross section of a molded product obtained by curing and molding the resin composition, the content of silica powder having a large particle size is set so that the variation value of the distribution state of Si element is 70 or less. It can be adjusted by mixing conditions for mixing raw materials, fine grinding of the mixture, introduction of a fine grinding process for the purpose of preventing aggregation, and the like.

The silica powder used in the present invention is not particularly limited in crystal structure, and either fused silica powder or crystalline silica powder can be used. Further, the shape is not particularly limited, and either an indefinite shape or a spherical shape can be used. However, the silica powder used in the present invention has an average particle size of 30 μm or less, the content of particles having a particle size of 150 μm or more is less than 1% by weight in the total silica powder, and contains particles having a particle size of 75 μm or more. It is essential that the amount is less than 10% by weight in the total silica powder. Preferably, the average particle diameter of the silica powder is 25 μm or less, the content of particles of 75 μm or more is less than 0.5% by weight in the total silica powder, and the content of particles of 53 μm or more is all silica. Less than 1% by weight in the powder.
This is because when the average particle size is large and there are many particles having a specific particle size or more, the local stress applied to the semiconductor element increases, peeling at the interface between the semiconductor element and the cured product of the epoxy resin composition, This is because the wiring layer is destroyed. Further, the silica powder used in the present invention may be subjected to a treatment for improving the compatibility with the resin component, including a treatment with a general coupling agent.
Although it does not specifically limit as content of the silica powder used for this invention, 60 to 96 weight% is preferable in all the epoxy resin compositions, More preferably, it is 80 to 93 weight%. If the lower limit value is not reached, sufficient solder resistance may not be obtained, and if the upper limit value is exceeded, sufficient fluidity may not be obtained.

  The epoxy resin used in the present invention refers to monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule, and the molecular weight and molecular structure are not particularly limited. For example, phenylene and / or biphenylene Aralkyl epoxy resin having skeleton, biphenyl epoxy resin, bisphenol epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol epoxy resin, naphthalene epoxy resin, dicyclopentadiene modified phenol epoxy resin, alkyl Modified triphenol methane type epoxy resin, triazine nucleus-containing epoxy resin and the like can be mentioned, and these may be used alone or in combination. Among them, a phenol aralkyl type epoxy resin having a phenylene and / or biphenylene skeleton having a long toughness between crosslinks and having a toughness is particularly preferable because it hardly causes cracks during mounting by IR reflow, and has a biphenylene skeleton. Aralkyl type epoxy resins are more preferred. Further, in order to improve the moisture resistance of the resin composition, it is desirable that impurity ions such as Cl ions and Na ions are as small as possible. From the viewpoint of curability, the epoxy equivalent is preferably 150 to 300 g / eq.

  Examples of the curing agent used in the present invention include phenolic, amine-based, polyaminoamide-based, and acid anhydride-based types, and their molecular structures are not particularly limited. For example, phenolic novolak resins and cresols are used for phenol-based curing agents. Novolak resin, dicyclopentadiene modified phenol resin, phenol aralkyl resin having phenylene and / or biphenylene skeleton, triphenol methane resin, terpene modified phenol resin, triphenol methane type phenol resin, etc., amine type aliphatic diamine, polyamine, aromatic Aliphatic diamines and polyamines, such as aliphatic anhydrides, alicyclics, and aromatics in acid anhydrides, and polyaminobismaleimides and derivatives thereof in polyaminoamides are used alone or in combination. There is no problem. From the viewpoint of the reflow crack property mentioned above, a phenol aralkyl resin having a biphenylene skeleton is desirable.

  The hardening accelerator used for this invention should just accelerate | stimulate reaction of an epoxy resin and a hardening | curing agent, and what is generally used for the sealing material can be utilized. For example, there are diazabicycloalkenes such as 1,8-diazabicyclo (5,4,0) undecene-7 and derivatives thereof, organic phosphines such as triphenylphosphine, imidazole compounds such as 2-methylimidazole, etc. You may use individually or in mixture.

The epoxy resin composition of the present invention essentially comprises the components (A) to (D), but in addition to this, a silane coupling agent, a flame retardant, a flame retardant aid, a release agent, and a silicone-based agent In addition, various additives such as a synthetic rubber-based low stress agent, a coloring agent, and the like may be appropriately blended.
The epoxy resin composition of the present invention can be produced by, for example, mixing the components (A) to (D) and other additives with a mixer, etc., further melt-kneading with a hot roll or kneader, etc., cooling and pulverizing. Good.
In order to improve the dispersibility of the Si element, not only the above-described mixer is used but also the dispersibility can be further improved by using a batch-type ball mill, a continuous ball mill, and measures corresponding thereto. In order to prevent aggregation, it is important not to leave it for a long time after mixing. Specifically, it is desirable to perform the melt-kneading step within 12 hours after mixing.

  In order to manufacture a semiconductor device using the epoxy resin composition of the present invention, it may be cured by a conventional molding method such as transfer molding, compression molding, injection molding or the like.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. The blending ratio is parts by weight.
Example 1

Epoxy resin 1: phenol aralkyl type epoxy resin having a biphenylene skeleton represented by the formula (3) (softening point: 58 ° C., epoxy equivalent: 272 g / eq) 8.0 parts by weight

Phenol resin 1: phenol aralkyl resin having a biphenylene skeleton represented by the formula (4) (softening point 65 ° C., epoxy equivalent 200 g / eq) 6.0 parts by weight

1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU)
0.2 parts by weight Fused silica powder 1 (average particle size 20 μm, blending ratio of particles having a particle diameter of 150 μm or more, less than 0.1 wt%, blending ratio of particles having a particle diameter of 75 μm or more, 0.5 wt%, spherical) 85. 5 parts by weight Carnauba wax 0.3 parts by weight was mixed at room temperature with a mixer, kneaded with a biaxial kneader at 80 to 110 ° C., cooled and ground to obtain an epoxy resin composition. The evaluation results are shown in Table 1.

Evaluation method EPMA dispersibility: Measurement was performed using JXA-8600M manufactured by JEOL Ltd. under the following measurement conditions.
Acceleration voltage: 15.0kV
Flow current: 5.0 × 10 ^-8
Resolution: 20 μm
Measurement area: 8.0 × 8.0 mm (400 pixels × 400 pixels)
Analysis time: 150ms / pixel
Measuring element: Si
The molded article of the epoxy resin composition was created under the following molding conditions.
Molding temperature: 170 ° C
Molding pressure: 2.9 MPa
Molding time: 120 seconds A sample obtained by cutting an epoxy resin composition molded product (50φ mm, thickness 3 mm) prepared under the above conditions into a size of about 18 mm × 18 mm is embedded with an epoxy resin embedding agent, and the observation surface After polishing and polishing, vapor deposition was performed to obtain an EPMA measurement sample.
In the data analysis of dispersibility, the distribution state of Si element was treated as intensity, and the intensity variation was calculated as standard deviation. Here, the n number of measurement was 160,000.

  Solder resistance: 100 pTQFP of epoxy resin composition under molding conditions of mold temperature of 175 ° C., injection pressure of 7.3 MPa, curing time of 1 minute (the size of the semiconductor element is 8.0 × 8.0 mm, the lead frame is made of Cu alloy) ) And post-cured at 175 ° C. for 8 hours. The obtained package was humidified for 168 hours at 85 ° C. and 85% relative humidity, and then immersed in a solder bath at 240 ° C. for 10 seconds. The presence or absence of peeling of the interface between the semiconductor element and the cured product of the epoxy resin composition and the presence or absence of destruction of the element wiring layer were observed with a microscope (n = 10). Regarding the peeling of the interface between the semiconductor element and the cured product of the resin composition, the peeling area exceeding 20% was rejected, and the breaking of the element wiring layer was rejected.

Examples 2-5, Comparative Examples 1-3
Each component was mix | blended in the ratio shown in Table 1, the epoxy resin composition was obtained like Example 1, and it evaluated similarly to Example 1. FIG. The results are shown in Table 1.
Example 5
In the compounding of Example 4, the components of the same compounding were mixed at room temperature with a mixer, the mixture was finely pulverized and mixed using a ball mill, kneaded with a twin-screw kneader at 80 to 110 ° C. 6 hours after preparation, and after cooling An epoxy resin composition was obtained by pulverization. The evaluation results are shown in Table 1.

The components used in other than Example 1 are shown below.
Epoxy resin 2: biphenyl type epoxy resin (YSR 4000H manufactured by JSR, softening point 109 ° C., epoxy equivalent 190)
Epoxy resin 3: dicyclopentadiene type epoxy resin (HP-7200, manufactured by Dainippon Ink, softening point 60 ° C., epoxy equivalent 263)
Phenol resin 2: Phenol aralkyl resin having a phenylene skeleton (Mitsui Chemicals XL225-LL, softening point 75 ° C., hydroxyl equivalent 174)
Fused silica powder 2 (average particle size of 13 μm, particle content of 150 μm or larger, 0.1% by weight, particle size of 75 μm or larger, 2.0% by weight, irregular)
Fused silica powder 3 (average particle size 28 μm, mixing ratio 0.1% by weight of particles having a particle diameter of 150 μm or more, mixing ratio 1.0% by weight of particles having a particle diameter of 75 μm or more, spherical)
Fused silica powder 4 (mixing ratio of particles having an average particle diameter of 15 μm, particle diameter of 150 μm or more, less than 0.1 wt%, mixing ratio of particles of particle diameter of 75 μm or more, mixing of particles having a particle diameter of 53 μm or more (0.5% by weight, spherical)
Fused silica powder 5 (average particle size 40 μm, mixing ratio of particles having a particle diameter of 150 μm or more 2% by weight, mixing ratio of particles having a particle diameter of 75 μm or more, spherical)
Fused silica powder 6 (average particle size 18 μm, mixing ratio 2% by weight of particles having particle diameter 150 μm or more, mixing ratio 8% by weight of particles having particle diameter 75 μm or more, irregular shape)
Fused silica powder 7 (average particle size 28 μm, mixing ratio of particles of particle size 150 μm or more 0.5 wt%, mixing ratio of particles of particle diameter 75 μm or more, spherical)

  According to the present invention, an epoxy resin composition capable of significantly reducing damage to an element due to stress generated during assembly or stress due to reflow heating during mounting in a semiconductor device using an element having low dielectric characteristics, and the same Therefore, it can be suitably used for semiconductor devices for consumer use such as industrial use such as communication and personal computers.

Claims (7)

(A) epoxy resin, (B) curing agent, (C) curing accelerator, and (D) the average particle size is 30 μm or less, and the content of particles having a particle size of 150 μm or more is less than 1% by weight in the total silica powder. And an epoxy resin composition for encapsulating a semiconductor containing silica powder whose content of particles having a particle size of 75 μm or more is less than 10% by weight in the total silica powder, and curing the resin composition When the EPMA (Electron Probe Micro Analyzer) analysis is performed on an arbitrary cross section of the molded product, the epoxy resin composition has a variation value of Si element distribution of 70 or less. The silica powder has an average particle size of 25 μm or less, the content of particles having a particle size of 75 μm or more is less than 0.5% by weight in the total silica powder, and the content of particles having a particle size of 53 μm or more is all. 2. The epoxy resin composition according to claim 1, wherein the epoxy resin composition is less than 1% by weight of silica powder. The epoxy resin composition according to claim 1 or 2, wherein a dispersion value of the dispersion state of the Si element in the EPMA analysis is 50 or less. The epoxy resin composition according to claim 1, wherein the epoxy resin is an epoxy resin represented by the general formula (1).

(In the formula, R1 and R2 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. A is an integer of 0 to 3, b is an integer of 0 to 4. n is an average value. , A positive number from 1 to 5.) The epoxy resin composition according to claim 1, wherein the curing agent is a phenol resin represented by the general formula (2).

(In the formula, R1 and R2 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. A is an integer of 0 to 3, b is an integer of 0 to 4. n is an average value. , A positive number from 1 to 5.) The said epoxy resin is an epoxy resin represented by General formula (1), and the said hardening | curing agent is a phenol resin represented by General formula (2), Either of Claim 1, 2, or 3 Epoxy resin composition.

(In the formula, R1 and R2 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. A is an integer of 0 to 3, b is an integer of 0 to 4. n is an average value. , A positive number from 1 to 5.)

(In the formula, R1 and R2 are hydrogen or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. A is an integer of 0 to 3, b is an integer of 0 to 4. n is an average value. , A positive number from 1 to 5.) A semiconductor device comprising a semiconductor element sealed with the epoxy resin composition according to claim 1.