JP2001329147A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for sealing a semiconductor, excellent in moldability, flame retardancy, characteristics in high temperature preservation, and moisture proof reliability without containing a halogen-based flame retardant and an antimony compound. SOLUTION: This epoxy resin composition for sealing the semiconductor is characterized in that the composition consists essentially of (A) an epoxy resin, (B) a phenol resin, (C) a curing accelerator, (D) an inorganic filler, (E) magnesium hydroxide having <=1,000 ppm chlorine ion content, and (F) red phosphorus or a red phosphorus-based flame retardant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation which does not contain a halogen-based flame retardant and an antimony compound and has excellent flame retardancy and high-temperature storage characteristics, and a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are mainly sealed with an epoxy resin composition. These epoxy resin compositions contain a halogen-based flame retardant and an antimony compound in order to impart flame retardancy. However, development of an epoxy resin composition having excellent flame retardancy without using a halogen-based flame retardant or an antimony compound is required from the viewpoint of environment and hygiene. Further, when a semiconductor device sealed with an epoxy resin composition containing a halogen-based flame retardant and an antimony compound is stored at a high temperature, a thermally decomposed halide is liberated from these flame retardant components to form a joint between semiconductor elements. Epoxy resin composition which is known to corrode the semiconductor device and impair the reliability of the semiconductor device, and can achieve a flame retardant grade of UL94 V-0 without using a halogen-based flame retardant or an antimony compound as a flame retardant. Is required.

[0003] As described above, the corrosion resistance of the bonding portion (bonding pad portion) of a semiconductor element after storing a semiconductor device at a high temperature (for example, 185 ° C or the like) is called high-temperature storage characteristics. As a method for improving the characteristics, a method using diantimony pentoxide (Japanese Patent Laid-Open No.
146950) and a method of combining antimony oxide with an organic phosphine (Japanese Patent Application Laid-Open No. 61-53321) have been proposed and their effects have been confirmed. On the other hand, some types of epoxy resin compositions are not satisfactory. In addition, a red phosphorus-based flame retardant has been proposed as a flame retardant. A flame retardant grade V-0 can be achieved by adding a large amount thereof, and there is no problem in high-temperature storage characteristics, but a large amount of phosphate ions as a by-product is contained. In such a case, there is a problem that the moisture resistance reliability and the moldability are reduced. Further, it has been proposed to solve the flame retardancy and the moisture resistance reliability by using a specific metal oxide in combination with a specific metal hydroxide and using a composite metal hydroxide of the specific metal oxide. (See, for example,
251486, JP-A-11-11945, etc.), in order to exhibit sufficient flame retardancy, a large amount of addition is required, and there is a problem that moldability is reduced. That is, there is a need for an epoxy resin composition that maintains flame retardancy without using a halogen-based flame retardant or antimony compound, and is excellent in moldability, high-temperature storage characteristics, and moisture resistance reliability.

[0004]

DISCLOSURE OF THE INVENTION The present invention does not include a halogen-based flame retardant and an antimony compound, and has good moldability and flame retardancy.
An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation excellent in high-temperature storage characteristics and humidity resistance, and a semiconductor device in which a semiconductor element is encapsulated using the same.

[0005]

Means for Solving the Problems The present invention provides [1] (A)
Epoxy resin, (B) phenolic resin, (C) curing accelerator, (D) inorganic filler, (E) chloride ion content of 10
An epoxy resin composition for semiconductor encapsulation comprising, as essential components, magnesium hydroxide of not more than 00 ppm and (F) red phosphorus or a red phosphorus-based flame retardant, [2] water having a chlorine ion content of not more than 1000 ppm The epoxy resin composition for semiconductor encapsulation according to item [1], wherein the magnesium oxide has a particle shape having an aspect ratio of 1 to 10, [3] red phosphorus or a red phosphorus-based flame retardant having an average particle diameter of 0.1 to 10. 30μm, maximum particle size 75μ
m or less, the epoxy resin composition for semiconductor encapsulation according to [1] or [2], [4] a red phosphorus-based flame retardant coated on the surface of red phosphorus with an inorganic compound and / or a curable resin. The epoxy resin composition for semiconductor encapsulation according to any one of the items [1] to [3], [5] the red phosphorus-based flame retardant, after coating the surface of the red phosphorus with an inorganic compound, The epoxy resin composition for semiconductor encapsulation according to item [4], the surface of which is coated with a curable resin; [6] the inorganic compound used for coating the surface of red phosphorus is metal hydroxide or metal. The epoxy resin composition for semiconductor encapsulation according to the item [4] or [5], wherein the metal hydroxide used for coating the surface of red phosphorus is aluminum, magnesium, or zinc water. Oxide, and the metal oxide is an oxide of aluminum, magnesium, or zinc. [6] The epoxy resin composition for semiconductor encapsulation according to [6], [8] the epoxy resin composition according to any of [4] to [7], wherein the curable resin used for coating the surface of red phosphorus is a phenol resin or an epoxy resin. A semiconductor element is sealed using the epoxy resin composition for semiconductor encapsulation according to any one of [9] and the epoxy resin composition for semiconductor encapsulation according to any of [1] to [8]. A semiconductor device.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having two or more epoxy groups in one molecule, and the molecular weight, molecular structure and the like are not particularly limited. 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 methane type epoxy resin, alkyl-modified triphenol methane type epoxy resin, epoxy containing triazine nucleus Resin, dicyclopentadiene-modified phenol type epoxy resin, phenol aralkyl type epoxy resin (having phenylene skeleton, biphenylene skeleton, etc.),
A naphthol type epoxy resin may be used, and these may be used alone or in combination of two or more. Of these, biphenyl type epoxy resin, cresol novolak type epoxy resin, dicyclopentadiene modified phenol type epoxy resin and the like are particularly preferable.

The phenolic resin used in the present invention includes:
It refers to all monomers, oligomers and polymers having two or more phenolic hydroxyl groups in one molecule, and does not particularly limit the molecular weight, molecular structure, etc., for example, phenol novolak resin, cresol novolak resin, dicyclopentadiene modified Phenolic resins, terpene-modified phenolic resins, triphenolmethane type resins, phenol aralkyl resins (having a phenylene skeleton, biphenylene skeleton, etc.), naphthol aralkyl resins (having a phenylene skeleton, biphenylene skeleton, etc.), and the like,
These may be used alone or in combination of two or more. Among these, especially phenol novolak resins,
A cresol novolak resin, a phenol aralkyl resin (having a phenylene skeleton, a biphenylene skeleton, and the like) are desirable. The amount of these components is preferably 0.8 to 1.3 in terms of the ratio of the number of epoxy groups of all epoxy resins to the number of phenolic hydroxyl groups of all phenolic resins.

As the curing accelerator used in the present invention, any one can be used as long as it promotes a curing reaction between an epoxy group and a phenolic hydroxyl group, and those generally used for a sealing material can be used. For example, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, 2-methylimidazole, tetraphenylphosphonium / tetraphenylborate and the like can be mentioned, and these can be used alone or in combination of two or more kinds. No problem.

As the inorganic filler used in the present invention, those generally used for a sealing material can be used. For example, fused silica, crystalline silica, talc, alumina, silicon nitride, aluminum hydroxide, and the like can be mentioned, and these may be used alone or in combination of two or more. Among these, the total amount of fused silica with high sphericity,
Alternatively, it is preferable to use partially crushed silica. The average particle size of the inorganic filler is preferably 5 to 30 μm, and the maximum particle size is preferably 74 μm or less. Further, by mixing particles having different particle sizes, the filling amount can be increased. As the inorganic filler, a material which has been surface-treated with a silane coupling agent or the like in advance may be used. As the content of the inorganic filler, the balance between the inorganic filler and the chloride ion content is 1000 pp from the balance between moldability and solder crack resistance.
The total amount of the epoxy resin composition and magnesium hydroxide of m or less is preferably 60 to 95% by weight in the total epoxy resin composition. 60% by weight
If it is less than 95%, the solder cracking resistance decreases with an increase in the moisture absorption rate. If it exceeds 95% by weight, there is a possibility that problems such as wire sweep and pad shift may occur.

The chlorine ion content used in the present invention is 100
Magnesium hydroxide of 0 ppm or less acts as a flame retardant and an ion scavenger, and as a flame retardant mechanism, it is known that dehydration starts at the time of combustion and the combustion reaction is inhibited by absorbing heat. Further, as an ion scavenger, it is possible to scavenge impurity anions in the system by a mechanism of scavenging anions and releasing hydroxyl ions. Usually, magnesium hydroxide is produced from seawater or rock salt and is prepared, and thus often contains a high concentration of chloride ions. However, when it is used for an epoxy resin composition for encapsulating a semiconductor element, it is desirable that chlorine ions be as small as possible. The chlorine ion content in magnesium hydroxide is more preferably 700 ppm or less.
Chloride ion content in magnesium hydroxide is 1000p
If it exceeds pm, the moisture resistance reliability of the semiconductor device sealed with the epoxy resin composition using the same significantly decreases, which is not preferable. As a method for measuring the chloride ion content, 4 g of magnesium hydroxide and 20 g of pure water were added at 125 ° C. for 2 hours.
After a pressure cooker treatment for 4 hours to extract chloride ions from magnesium hydroxide, the extracted water is analyzed by ion chromatography to determine the amount of chloride ions per unit weight of magnesium hydroxide.

The magnesium hydroxide of the present invention may have a hexagonal plate shape or a spherical shape, but preferably has a particle aspect ratio of 1 to 10, and more preferably a true spherical shape, from the viewpoint of improving fluidity. Is desirable. The average particle size of the magnesium hydroxide of the present invention is 0.5 to 100 μm
And more preferably 0.5 to 30 μm.
Further, the surface of magnesium hydroxide may be coated with a resin, a coupling agent, a wax, or the like. The amount of the magnesium hydroxide of the present invention is preferably 0.1 to 15% by weight, more preferably 0.2 to 5% by weight, based on the total epoxy resin composition. If it is less than 0.1% by weight, flame retardancy is insufficient, and if it exceeds 15% by weight, solder crack resistance and moldability may be reduced.

The red phosphorus or red phosphorus flame retardant used in the present invention is:
It acts as a flame retardant. As the red phosphorus, fine particles made of red phosphorus obtained by directly spheroidizing yellow phosphorus and an aggregate thereof are preferable because the fluidity during molding of the epoxy resin composition is improved. The red phosphorus-based flame retardant is not particularly limited, but is preferably one in which the surface of red phosphorus is coated with an inorganic compound and / or a curable resin. When the inorganic compound and the curable resin are used in combination for coating, any of the inorganic compound layer and the curable resin layer coated on the red phosphorus may be either inside or outside, or the inorganic compound and the curable resin. May be mixed and used for coating. In particular, it is preferable to use a material obtained by coating the surface of red phosphorus with an inorganic compound and then further coating the surface with a curable resin, because phosphate ions and phosphite ions that elute can be suppressed.

The inorganic compound used for the coating is not particularly limited, and examples thereof include metal hydroxides, metal oxides, metal nitrides, metal salts with inorganic or organic acids, and the like. In particular, a metal hydroxide or a metal oxide having an effect of suppressing hydrolysis of red phosphorus is preferable, and a hydroxide or an oxide of aluminum, magnesium, or zinc is more preferable. These inorganic compounds may be used alone or in combination of two or more.

The curable resin used for the coating is not particularly limited. For example, a phenol resin, an epoxy resin, a xylene / formaldehyde resin, a ketone resin
Formaldehyde resin, urea resin, melamine resin, aniline resin, alkyd resin, unsaturated polyester resin and the like, phenolic resin, especially those that do not decrease the fluidity and curability during molding of the low hygroscopicity and epoxy resin composition, Epoxy resins are preferred. These curable resins may be used alone or in combination of two or more. The method for curing the curable resin may be normal temperature or heating, and is not particularly limited.

That is, as the red phosphorus-based flame retardant of the present invention, red phosphorus whose surface is coated with aluminum hydroxide and further coated with a phenol resin or an epoxy resin is more preferable. The phenolic resin used for coating is not particularly limited, but refers to monomers, oligomers, and polymers in general having two or more phenolic hydroxyl groups in one molecule. Resins, resol resins, etc., may be used alone or in combination of two or more. The epoxy resin used for coating is not particularly limited, but refers to all monomers, oligomers, and polymers having two or more epoxy groups in one molecule,
For example, a biphenyl type epoxy resin, a bisphenol type epoxy resin, a novolak type epoxy resin and the like can be mentioned, and these may be used alone or in combination of two or more. There is no restriction on the coating method, but for example, from the viewpoint of coating uniformity, red phosphorus is coated by reducing aluminum sulfate, aluminum nitrate, etc. in the liquid phase to change to aluminum hydroxide. Further, a method of using an acid in a resole resin solution, coating with a generated phenol resin, and drying is used.

The content of red phosphorus in the red phosphorus flame retardant is as follows:
90-96% by weight is preferred. If it is less than 90% by weight, the coating layer becomes thick and its effect as a flame retardant decreases, and if it exceeds 96% by weight, the coating layer becomes thin and undergoes a hydrolysis reaction in the presence of moisture, so that phosphoric acid is easily converted from red phosphorus. Since ions and phosphite ions are generated, there is a possibility that a problem may occur in terms of humidity resistance reliability. As the red phosphorus or the red phosphorus-based flame retardant, those having an average particle diameter of 0.1 to 30 μm and a maximum particle diameter of 75 μm or less are preferable. If the average particle size is less than 0.1 μm, aggregation or the like occurs,
If it exceeds 30 μm, the dispersibility may decrease. In order to improve dispersibility, the maximum particle size is preferably 75 μm or less, and if it exceeds 75 μm, the dispersibility tends to decrease. Examples of the coated red phosphorus-based flame retardant include Nova Excel manufactured by Rin Kagaku Kogyo Co., Ltd., which can be easily obtained from the market. The compounding amount of red phosphorus or a red phosphorus-based flame retardant is preferably 0.2 to 2% by weight in the total epoxy resin composition. If it is less than 0.2% by weight, the flame retardancy is insufficient, and if it exceeds 2% by weight, the moisture resistance reliability may be significantly reduced.

The magnesium hydroxide and red phosphorus or red phosphorus-based flame retardant of the present invention each have a property of imparting flame retardancy even when used alone. However, in order to exhibit sufficient flame retardancy, a large amount of flame retardant is required. Is required. However, when blended in a large amount, the moldability and strength tend to decrease, and the moisture absorption tends to increase,
Solder crack resistance is reduced. In order to prevent these physical properties from deteriorating, it is necessary to reduce the compounding amount as much as possible. The present inventor has confirmed that the combined use of the magnesium hydroxide and red phosphorus or a red phosphorus-based flame retardant can further improve the flame retardancy and reduce the compounding amount as a synergistic effect. Furthermore, it has been found that moisture resistance reliability and high-temperature storage characteristics are significantly improved by capturing alkaline ions of magnesium hydroxide from red phosphorus or a red phosphorus-based flame retardant. That is, it has been found that by using both of them, high flame retardancy and high reliability as well as good moldability can be achieved as synergistic effects.

The epoxy resin composition of the present invention comprises (A)
The component (F) is an essential component, but if necessary, a silane coupling agent, a coloring agent such as carbon black, a release agent such as a natural wax and a synthetic wax, and low-stress addition such as silicone oil and rubber. Various additives such as an agent may be appropriately compounded. The epoxy resin composition of the present invention is obtained by mixing the components (A) to (F) and other additives sufficiently and uniformly using a mixer or the like, and further melt-kneading with a hot roll or a kneader and cooling. Obtained by grinding. Various electronic components such as semiconductor elements are encapsulated using the epoxy resin composition of the present invention, and semiconductor devices are manufactured by curing and molding using conventional molding methods such as transfer molding, compression molding, and injection molding. do it.

[0019]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. The mixing ratio is by weight. The abbreviations of the magnesium hydroxide and the red phosphorus-based flame retardant used in Examples and Comparative Examples are shown below. Magnesium hydroxide 1: hexagonal plate with an aspect ratio of 4.3, average particle size of 5 μm, chlorine ion impurity content of 475 pp
m. It is coated with a glycidyl type epoxy silane coupling agent. Magnesium hydroxide 2: aspect ratio 2.
No. 1 rice grain, average particle size 15 μm, chlorine ion impurity content 210 ppm. Magnesium hydroxide 3: hexagonal plate with an aspect ratio of 5.2, average particle size of 7 μm, and chlorine ion impurity content of 1229 ppm. Red Phosphorus Flame Retardant 1: A surface of red phosphorus converted directly from yellow phosphorus into spheres, coated with aluminum hydroxide, and then further coated with a phenol resin. The content of red phosphorus is 94% by weight, average. Particle size 20μ
m, maximum particle size 51 μm. Red Phosphorus Flame Retardant 2: A substance obtained by coating the surface of ground red phosphorus with aluminum hydroxide and then further coating the surface with an epoxy resin. The content of red phosphorus is 94% by weight, the average particle size is 22 μm, and the maximum particle size is Diameter 50 μm.

Example 1 77 parts by weight of biphenyl type epoxy resin (YX-4000 manufactured by Japan Epoxy Resin Co., Ltd.) 68 parts by weight of phenol aralkyl type resin (XLC-3L manufactured by Mitsui Chemicals, Inc.) 1,8- Diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 2 parts by weight Fused spherical silica 825 parts by weight Magnesium hydroxide 1 10 parts by weight Red phosphorus-based flame retardant 1 5 parts by weight Epoxysilane coupling agent 5 parts by weight 3 parts by weight of carbon black and 5 parts by weight of carnauba wax were mixed at room temperature using a super mixer, and 70 to 10 parts were mixed.
Roll kneading was performed at 0 ° C., followed by cooling and pulverization to obtain an epoxy resin composition. The obtained epoxy resin composition was evaluated by the following method. Table 1 shows the results.

<Evaluation Method> Spiral flow: Measured using a mold for measuring spiral flow according to EMMI-1-66 at a mold temperature of 175 ° C., a pressure of 6.9 MPa, and a curing time of 120 seconds. The unit is cm. Curability: Using a JSR Curastometer IVPS manufactured by Orientec Co., Ltd., the diameter of the die was 35 mm, the amplitude angle was 1 °, the molding temperature was 175 ° C., and the torque value after 90 seconds from the start of molding was measured. The higher the value, the faster the curing. The unit is N · m. Flame retardancy: A test piece (127 mm × 12.7 mm × 3.2 mm) was molded using a low pressure transfer molding machine at a molding temperature of 175 ° C., a pressure of 6.9 MPa, and a curing time of 120 seconds. After treatment for 8 hours, ΔF and Fmax were measured according to the UL-94 vertical method,
Flame retardancy was determined. High-temperature storage characteristics: Using a low-pressure transfer molding machine, a molding temperature of 175 ° C., a pressure of 6.9 MPa, and a curing time of 120 seconds, 16 pDIP (chip size: 3.0 mm × 3.5 m)
m) was molded and treated as an after-bake at 175 ° C. for 8 hours, followed by a high-temperature storage test (185 ° C., 1000 hours)
The package in which the electric resistance between the wirings increased by 20% from the initial value was determined to be defective. The number of defective packages in the 15 packages is shown. Moisture resistance reliability: 16pDIP (chip size 3.0mm x 3.5mm) using a low pressure transfer molding machine at a molding temperature of 175 ° C, a pressure of 6.9MPa, and a curing time of 120 seconds.
And then treated at 175 ° C. for 8 hours as an after-bake, and then subjected to 125 ° C., 20 ° C. while applying a bias of 20V.
A 0 hour treatment was performed. The conduction between the wirings was confirmed, and the state where the conduction was lost was determined to be defective. The number of defective packages in the 15 packages is shown.

Examples 2 to 5 and Comparative Examples 1 to 5 According to the composition shown in Table 1, an epoxy resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. The properties of the epoxy resin and phenol resin used in Examples 4 and 5 are shown below. Dicyclopentadiene-modified phenolic epoxy resin (HP-7200 manufactured by Dainippon Ink and Chemicals, Inc.), phenol novolak resin (PR-5171 manufactured by Sumitomo Durez, Inc.)
4). The epoxy equivalent of the brominated bisphenol A type epoxy resin used in Comparative Example 1 is 365.

[Table 1]

[0023]

According to the present invention, an epoxy resin composition for encapsulating a semiconductor which does not contain a halogen-based flame retardant or an antimony compound and has excellent moldability can be obtained. Excellent storage characteristics and moisture resistance reliability.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 23/29 H01L 23/30 R 23/31

Claims (9)

[Claims] 1. An epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, (E) magnesium hydroxide having a chloride ion content of 1000 ppm or less, and (F) An epoxy resin composition for semiconductor encapsulation, comprising red phosphorus or a red phosphorus-based flame retardant as an essential component. 2. A magnesium hydroxide having a chloride ion content of 1000 ppm or less has an aspect ratio of 1 to 1 in particle shape.
The epoxy resin composition for semiconductor encapsulation according to claim 1, which is 10. 3. The method according to claim 1, wherein the red phosphorus or the red phosphorus-based flame retardant has an average particle diameter of 0.
The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, having a particle size of 1 to 30 µm and a maximum particle size of 75 µm or less. 4. The red phosphorus flame retardant wherein the surface of red phosphorus is coated with an inorganic compound and / or a curable resin.
4. The epoxy resin composition for semiconductor encapsulation according to any one of items 1 to 3. 5. The epoxy resin composition for semiconductor encapsulation according to claim 4, wherein the red phosphorus flame retardant is obtained by coating the surface of red phosphorus with an inorganic compound and then coating the surface with a curable resin. . 6. The inorganic compound used for coating the surface of red phosphorus is a metal hydroxide or a metal oxide.
The epoxy resin composition for semiconductor encapsulation according to the above. 7. The metal hydroxide used for coating the surface of red phosphorus is a hydroxide of aluminum, magnesium or zinc, and the metal oxide is an oxide of aluminum, magnesium or zinc. 7. The epoxy resin composition for semiconductor encapsulation according to 6. 8. The curable resin used for coating the surface of red phosphorus is a phenol resin or an epoxy resin.
8. The epoxy resin composition for semiconductor encapsulation according to any one of 7. 9. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.