JP2000095923A - Sealing epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing epoxy resin composition which can give a cured product having resistance to buildup of electrostatic charges and excellent reliability of humidity resistance by incorporating an epoxy resin with a curing agent, an inorganic filler, and an ionic surfactant. SOLUTION: This composition is prepared by forming 0.01-1 pt.wt., per 100 pts.wt. sealing resin, a layer of an ionic surfactant on the surface of each particle of a resin composition containing 0.1-10 equivalents, per equivalent of the epoxy resin, of a curing agent such as an epoxy resin or a phenol novolac resin; 60-95 pts.wt., per 100 pts.wt. sealing resin, inorganic filler such as crystalline silica or alumina; and, optionally, a cure accelerator, a flame retardant, a colorant, an ion trapping agent, a coupling agent, etc. The epoxy resin used is an o-cresol novolac epoxy resin or a bisphenol A epoxy resin each having at least two epoxy groups in the molecule. The ionic surfactant used is an anionic one, a cationic one, an amphoteric one, or a mixture thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a sealing epoxy resin composition used for manufacturing the same.

[0002]

2. Description of the Related Art As a method of sealing electronic parts such as semiconductor devices, a method of sealing by transfer molding using an epoxy resin composition is widely used. As an epoxy resin composition for sealing used in this transfer molding (hereinafter referred to as a sealing resin), after mixing an epoxy resin, a curing agent, an inorganic filler, and the like, kneading while heating with a roll or an extruder, The kneaded material is stretched into a sheet and cooled, and then pulverized, or a method using a sealing resin pulverized material formed by extruding the kneaded material linearly and cutting it while cooling, or a method in which the pulverized material is subjected to a predetermined method After weighing or measuring the volume, a method is used in which a tablet-shaped sealing resin is inserted into a mold having a cylindrical hole, and formed into a cylindrical shape while evacuating the internal air by applying pressure. I have.

In transfer molding, a lead frame on which a semiconductor chip is mounted is mounted on a mold, and then a pulverized sealing resin or a tablet-like sealing resin is placed in a pot provided in the mold. After supplying, heating and melting, the sealing resin is transferred to the cavity in the mold by pressurizing with a plunger, and the sealing resin is cured by further heating, whereby the sealing is performed. Have been done.

[0004] When manufacturing a crushed product of a sealing resin,
When the crushed material is supplied into the pot or when the crushed material is transferred to the tablet forming mold, the crushed material rubs against each other or a pipe or the like, and is charged by friction, thereby producing the crushed material. There is a problem that it easily adheres to devices and the like, and a problem that clogging of piping and the like may occur. In addition, when transfer molding is performed using such a charged sealing resin, the sealing resin adheres to a pipe or the like and becomes difficult to be supplied in a predetermined amount. However, there is a problem in that may be formed.

When the sealing is performed by transfer molding, the sealing resin is filled with a surfactant such as polyethylene glycol fatty acid ester, sorbitan fatty acid ester or fatty acid monoglyceride so that the sealing resin is sufficiently filled in the cavity. It has been studied to improve the wettability with a mold by adding an agent. However, even in the case of a sealing resin containing a surfactant such as polyethylene glycol fatty acid ester, sorbitan fatty acid ester, or fatty acid monoglyceride, the pulverized material is easily charged,
There is a problem that it easily adheres to a manufacturing apparatus and the like, and a problem that a pipe and the like may be clogged.

As a countermeasure, it has been considered to suppress generation of static electricity by adding an antistatic agent to the sealing resin. However, in the case of a general antistatic agent, there is a possibility that the moisture resistance reliability of the obtained sealed product may be reduced, and it has been difficult to use it. Therefore, a sealing resin containing an epoxy resin, a curing agent, and an inorganic filler, which is hardly charged, is desired.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a sealing resin containing an epoxy resin, a curing agent and an inorganic filler. (Epoxy resin composition for sealing), which is to provide a sealing resin which is hardly charged and has excellent moisture resistance reliability. Another object of the present invention is to provide a semiconductor device in which an unfilled portion is less likely to be formed on the surface or inside.

[0008]

The sealing resin according to claim 1 of the present invention is a powdery sealing resin containing an epoxy resin, a curing agent, an inorganic filler and an ionic surfactant.

A sealing resin according to a second aspect of the present invention is a sealing resin in which a layer of an ionic surfactant is formed on the surface of a granular material containing an epoxy resin, a curing agent and an inorganic filler. It is.

A semiconductor device according to a third aspect of the present invention is obtained by encapsulating a semiconductor chip using the epoxy resin composition for encapsulation according to the first or second aspect.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The sealing resin according to the present invention is a powdery sealing resin containing at least an epoxy resin, a curing agent, an inorganic filler, and an ionic surfactant.
It is important to contain an ionic surfactant,
If not contained, the sealing resin is likely to be charged and easily adhered to a manufacturing apparatus, etc., a problem that a pipe may be clogged, and a problem that moisture resistance reliability is reduced. It is easy to occur.

Examples of the ionic surfactant include anionic surfactants such as alkyl phosphate salts and sulfonates, and cationic surfactants such as primary amine salts, tertiary amines, quaternary ammonium salts, and pyridine derivatives. Examples include an activator, an amphoteric surfactant such as a carboxylic acid derivative, an imidazoline derivative, a betaine salt, and an alanine salt. These may be used alone or in combination of two or more.

The amount of the ionic surfactant is preferably 0.01 to 1 part by weight based on 100 parts by weight of the sealing resin. When the amount is less than 0.01 part by weight, the effect of preventing electrification is small. When the amount exceeds 1 part by weight, a sealed product obtained by ionic impurities contained in the ionic surfactant (semiconductor device, etc.) In some cases, the moisture resistance reliability may decrease. In addition, as a surfactant,
It is not limited that only an ionic surfactant is blended, and a nonionic surfactant may be blended if necessary.

The epoxy resin used in the present invention is not particularly limited as long as it contains an epoxy resin having two or more epoxy groups in a molecule. For example, an ortho-cresol novolak type epoxy resin, bisphenol A
Type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin and the like. These may be used alone or in combination of two or more.

The curing agent used in the present invention is not particularly limited as long as it reacts with an epoxy resin and cures. For example, a phenol novolak resin, a cresol novolak resin, a mono- or dihydroxynaphthalene novolak resin, Phenolic curing agents such as resin derivatives, phenol aralkyl, naphthol aralkyl, and copolymers of dicyclopentadiene and phenol, amine curing agents, and acid anhydrides. The above curing agents may be used alone or in combination of two or more. In addition, as for the compounding quantity of a hardening | curing agent, it is mix | blended generally in the range of 0.1-10 in equivalent ratio with respect to an epoxy resin.

The inorganic filler used in the present invention is not particularly limited. Examples thereof include crystalline silica, fused silica,
Examples include alumina, magnesia, titania, calcium carbonate, magnesium carbonate, silicon nitride, talc, calcium silicate, and the like. The inorganic filler may be used alone or in combination of two or more. In addition, when silica, such as crystalline silica or fused silica, is used as the inorganic filler, the coefficient of linear expansion of the obtained sealed product is preferably small. The amount of the inorganic filler is not particularly limited, but may be 60 to 9 parts by weight in 100 parts by weight of the sealing resin.
It is preferable to contain 5 parts by weight. If less than 60 parts by weight,
The amount of moisture absorption of the obtained sealed product may increase, and the moisture absorption heat resistance may decrease. If it exceeds 95 parts by weight, the viscosity of the sealing resin increases, and the moldability during sealing may decrease. is there.

The sealing resin of the present invention may contain a curing accelerator, a release agent, a flame retardant, a coloring agent, a stress reducing agent, an ion trapping agent, a coupling agent, and the like, if necessary. . Examples of the curing accelerator include tertiary amine compounds such as 1,8-diaza-bicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, 2-methylimidazole, and 2-ethyl-4-methyl. Imidazole compounds such as imidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole,
Organic phosphine compounds such as triphenylphosphine and tributylphosphine are exemplified.

Examples of the release agent include fatty acids such as stearic acid, montanic acid, palmitic acid, oleic acid and linoleic acid, and calcium and magnesium salts of the fatty acids.
Aluminum salts, salts such as zinc salts, amides of their fatty acids,
Examples include phosphate esters, polyethylene, bisamides, carboxyl group-containing polyolefins, and natural carnauba. Examples of the flame retardant include antimony trioxide, halogen compounds, phosphorus compounds and the like. Examples of the coloring agent include carbon black and titanium oxide. Examples of the low stress agent include silicone gel, silicone rubber, silicone oil and the like. Two or more of these curing accelerators can be used in combination.

It is preferable that the sealing resin of the present invention is uniformly mixed, kneaded, and formed into a powder.
As the method, for example, after blending an epoxy resin, a curing agent, an inorganic filler, an ionic surfactant, and the like, uniformly mix with a mixer, a blender, and the like, and then knead while heating using a roll, a kneader, or the like. A method in which the kneaded material is stretched into a sheet and cooled, and then pulverized, or a method in which the kneaded material is extruded into a linear shape and cut while cooling to form the mixture.

It is to be noted that, after kneading a part or all of the ionic surfactant to be compounded without mixing during the above-mentioned kneading, a powder is similarly formed, and then the ionic surfactant is added. Mixing with a mixer, blender, etc., to form a layer of the ionic surfactant on the surface of the powdery granules, compared to the case of mixing and kneading all the ionic surfactants during kneading Since it is possible to prevent charging with a small amount of an ionic surfactant, the reliability of the obtained sealed product is particularly excellent and preferable.

Then, transfer molding or the like is performed using the sealing resin obtained as described above, and a semiconductor chip mounted on a lead frame, a semiconductor chip mounted on an organic substrate, or a semiconductor chip alone is used. By sealing, a semiconductor device (a semiconductor device according to claim 3 of the present invention) in which an unfilled portion is unlikely to be formed on the surface or inside is obtained. This is because the sealing resin to be used is a sealing resin having a small charge amount, so that it is difficult for the sealing resin to adhere to a pipe or the like and become difficult to be supplied in a predetermined amount, and to be surely filled in the cavity. It is difficult to form an unfilled portion on the surface or inside.

Since the semiconductor device is manufactured using a sealing resin which is difficult to be charged, the obtained semiconductor device also has a small charge amount, and the amount of burrs, dust, metal powder and the like adhered to the semiconductor device when used. Decrease. Therefore, an effect that the semiconductor device has excellent reliability can be obtained. The molding method is not particularly limited except that the sealing resin is used, and molding can be performed by a general method.

[0023]

Examples (Examples 1 to 6, Comparative Example 1) The following two types of epoxy resins, curing agents, curing accelerators, release agents, flame retardants, inorganic fillers, and ionic interfaces were used as raw materials for the sealing resin. Three activators were used. -Epoxy resin 1: ortho-cresol novolak type epoxy resin [manufactured by Sumitomo Chemical Co., Ltd., trade name ESCN195X]
L], ・ Epoxy resin 2: brominated epoxy resin [manufactured by Sumitomo Chemical Co., Ltd., trade name ESB400]; ・ Curing agent: phenol novolak resin [Gunei Chemical Co., Ltd.]
・ Accelerator: Triphenylphosphine [manufactured by Hokko Chemical Industry Co., Ltd.] ・ Release agent: Natural carnauba wax ・ Flame retardant: Antimony trioxide ・ Inorganic filler : Fused silica [Tatsumori, 3K]
・ Ionic surfactant 1: Cationic [Electron stripper QN manufactured by Kao Corporation] ・ Ionic surfactant 2: Anionic [Nippon Oil & Fat Co., Ltd.
Elegan A-2000SG (trade name); Ionic surfactant 3: amphoteric surfactant (trade name: Electrostripper AC, manufactured by Kao Corporation).

In Examples 1 to 3 and Comparative Example 1, each of the above-mentioned raw materials was blended at a weight ratio shown in Table 1, mixed with a blender for 30 minutes, and then heated using a kneader heated to 85 ° C. After kneading, melting, extruding, and cooling, the mixture was pulverized to a predetermined particle size by a pulverizer to obtain a granular sealing resin. In Examples 4 to 6, among the above-mentioned raw materials, the raw materials except for the ionic surfactant were blended at a weight ratio shown in Table 1, mixed in a blender for 30 minutes, and then heated to a temperature of 85 ° C. Using a kneader, knead and melted and extruded, after cooling, pulverized to a predetermined particle size with a pulverizer to form powder and granules,
Next, after putting this powder into a Henschel mixer,
By adding and mixing the ionic surfactant at the weight ratio shown in Table 1, a powdery and granular sealing resin having a layer of the ionic surfactant formed on the surface of the granular material was obtained.

[0025]

[Table 1]

(Evaluation and Results) The chargeability of the sealing resin obtained in each of the examples and comparative examples 1 and the evaluation samples prepared using the sealing resin obtained in each of the examples and comparative example 1 were evaluated. The humidity resistance reliability was measured.

The chargeability of the obtained sealing resin was 1.5 kgf / cm using a nylon tube (12 φ, 3 m) hose.
After air transportation at an air pressure of ² , evaluation was performed using a static electricity meter (rotating sector type electrometer, product name: Statilon M).

The moisture resistance reliability was measured using a transfer molding machine at a temperature of 17 ° C. using a transfer molding machine with a 42 alloy lead frame on which a test element on which an aluminum wiring having a width of 10 μm and a thickness of 1 μm was formed was interposed.
After molding under the conditions of 5 ° C. and a pressurization time of 90 seconds, post-curing was performed at 175 ° C. for 6 hours to prepare a sample for evaluation. Next, PCT treatment was performed on 10 evaluation samples under the condition of 2 atm / 121 ° C., and the number of disconnection failures of the aluminum wiring after 1000 hours was determined.

As a result, as shown in Table 1, it was confirmed that each example was less likely to be charged as compared with Comparative Example 1. Further, in each example, the moisture resistance reliability was equivalent to that of Comparative Example 1 containing no surfactant, and it was confirmed that the moisture resistance reliability was excellent. Examples 1 to 4 and Example 6, which contain 0.01 to 1 part by weight of the ionic surfactant with respect to 100 parts by weight of the sealing resin, have particularly excellent moisture resistance reliability as compared with Example 5. It was confirmed that.

[0030]

The sealing resin (epoxy resin composition for a sealing material) according to the present invention contains an ionic surfactant, so that it is difficult to be charged and has excellent reliability. .

The epoxy resin composition for sealing according to the second aspect of the present invention can prevent charging with a small amount of an ionic surfactant.

Since the semiconductor device according to the third aspect of the present invention is manufactured using a sealing resin containing an ionic surfactant, the semiconductor device is unlikely to have an unfilled portion on the surface or inside. .

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Claims (3)

[Claims] 1. A powdery and granular sealing epoxy resin composition comprising an epoxy resin, a curing agent, an inorganic filler and an ionic surfactant. 2. An epoxy resin composition for sealing, characterized in that a layer of an ionic surfactant is formed on the surface of a granular material containing an epoxy resin, a curing agent and an inorganic filler. 3. A semiconductor device in which a semiconductor chip is sealed using the epoxy resin composition for sealing according to claim 1.