JP2001310930A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition for a semiconductor sealing agent which is excellent in solder heat resistance (adhesion) and formability (external void, internal void, package surface appearance). SOLUTION: The epoxy resin composition is characterized by containing an epoxy resin (A), curing agent (B), curing accelerator (C), bulking agent (D) and silicon compound (E) as an essential component, and the content of the bulking agent is 83-95 wt.% of the whole resin composition, and this composition is characterized by containing an organic denatured silicon compound having a specific structure of silicon compound as an essential component.

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 excellent in solder heat resistance and moldability (void), and more particularly to an epoxy resin composition for semiconductor encapsulation and a semiconductor device.

[0002]

2. Description of the Related Art As a method of sealing an electronic circuit portion such as a semiconductor device, a sealing resin comprising an epoxy resin, a curing agent, and an inorganic filler is used in view of the balance between economy, productivity, and physical properties. Resin sealing has become common. With the recent increase in the number of pins, reduction in size and thickness, and increase in the size of chips in semiconductor devices, the demand for solder heat resistance and moldability for sealing resins has also increased.

[0003] In order to improve solder heat resistance, a filler content in a resin composition has been increased to reduce water absorption, but on the other hand, voids generated on a package surface or inside a package have increased. Was a problem.

To solve the above problems, Japanese Patent Laid-Open No. 8-33
As disclosed in Japanese Patent No. 7635, it has been proposed to reduce external voids by adding silicone oil.

[0005] However, only by adding silicone oil,
The effect of reducing external voids and internal voids is not sufficient,
Further, the silicone oil component sometimes oozes out on the package surface or has poor appearance (flow mark generation).

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation which is excellent in solder heat resistance (adhesion) and moldability (external voids, internal voids, package surface appearance). It is.

[0007]

That is, the present invention mainly comprises the following constitutions: "epoxy resin (A), curing agent (B), curing accelerator (C), filler (D), silicone Compound (E) is contained as an essential component, and the content of filler (D) is 83% based on the whole resin composition.
To 95% by weight, wherein the silicone compound (E) contains an organically modified silicone compound having the structure of the following formula (I) as an essential component, and the content of the silicone compound (E) is 0% based on the whole resin composition. 0.1 to 5% by weight of the epoxy resin composition for semiconductor encapsulation. "
It is.

[0008]

Embedded image (Where 0 ≦ x ≦ 1000, 0 ≦ y ≦ 300, 0 ≦ z ≦
300, 0 ≦ x + y + z ≦ 1300. R and R 'are an alkyl group or alkylene group having 1 to 10 carbon atoms, and the hydrogen of the alkyl group may be substituted with a hydroxyl group or an alkyl group. Further, 0 ≦ a ≦ 50, 0 ≦ b ≦ 5
0. )

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail.

The epoxy resin (A) in the present invention is not particularly limited as long as it has a plurality of epoxy groups in the molecule. Specific examples thereof include cresol novolak epoxy resin, phenol novolak epoxy resin, biphenyl Epoxy resin, stilbene epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, various novolak epoxy resins synthesized from bisphenol A and resorcinol,
Examples include a linear aliphatic epoxy resin, an alicyclic epoxy resin, a heterocyclic epoxy resin, a spiro ring-containing epoxy resin, and a halogenated epoxy resin. In the epoxy resin (A), two or more epoxy resins can be used in combination.

Among these epoxy resins (A), those which are particularly preferably used in the present invention have a biphenyl skeleton represented by the following general formula (II) because of their excellent solder heat resistance (adhesion). It contains an epoxy resin.

[0012]

Embedded image (However, R ₁ in the formula represents a hydrogen atom, an alkyl group or a halogen atom and may be the same or different.) Further, the epoxy resin (A) is a biphenyl skeleton represented by the above formula (II) It is preferable to contain an epoxy resin having a content of 50% by weight or more.

Preferred specific examples of the epoxy resin skeleton represented by the above formula (II) are 4,4'-bis (2,3-epoxypropoxy) biphenyl 4,4'-bis (2,3-epoxypropoxy) ) -3,3 ', 5,5'-Tetramethylbiphenyl 4,4'-bis (2,3-epoxypropoxy) -3,3', 5,5'-Tetraethylbiphenyl 4,4'-bis (2 , 3-epoxypropoxy) -3,3 ', 5,5'-tetrabutylbiphenyl and the like, and they are sufficiently effective when used alone or in a mixed system.

It is also preferable that the epoxy resin (A) contains an epoxy resin having a skeleton represented by the following general formula (III) from the viewpoint of moldability (internal void).

[0015]

Embedded image (However, n in the formula is an integer of 0 to 5, and R ₂ represents a hydrogen atom, an alkyl group or a halogen atom, and may be the same or different.) Further, the epoxy resin (A) is as described above. It is preferable to contain 15% by weight or more of an epoxy resin having a skeleton represented by the formula (III).

Further, the epoxy resin has a general formula (II)
It is more preferable to include both an epoxy resin having a biphenyl skeleton represented by Formula (1) and an epoxy resin having a skeleton represented by Formula (III). In this case, the general formula (I
In the present invention, the total of the epoxy resin having a biphenyl skeleton represented by I) and the epoxy resin having a skeleton represented by the general formula (III) is preferably 80% by weight or more in the epoxy resin (A). The amount of the epoxy resin (A) is usually 0.5 to 15% by weight, more preferably 2 to 10% by weight, based on the entire epoxy resin composition, from the viewpoint of moldability and adhesion. Epoxy resin (A)
If the blending amount is 0.5% by weight or more, the moldability and adhesion will not be insufficient, and if it is 15% by weight or less, the coefficient of linear expansion of the cured product will be large, There is no difficulty in stressing.

The curing agent (B) in the present invention is not particularly limited as long as it reacts with the epoxy resin (A) and cures. Usually a compound having a phenolic hydroxyl group,
Compounds having acid anhydrides and amines are used. Among these, specific examples of the phenolic curing agent, that is, the compound having two or more phenolic hydroxyl groups in the molecule include, for example, phenol novolak resin, cresol novolak resin, phenol aralkyl resin, bisphenol A, resorcin, and the like. Examples include various novolak resins, various polyhydric phenol compounds such as tris (hydroxyphenyl) methane, dihydrobiphenyl, and polyvinyl phenol.

Examples of the compound having an acid anhydride include maleic anhydride, phthalic anhydride, and pyromellitic anhydride.

Examples of the amines include aromatic amines such as metaphenylenediamine, di (aminophenyl) methane (commonly called diaminodiphenylmethane) and diaminodiphenylsulfone. For semiconductor encapsulation, a phenol-based curing agent is preferably used from the viewpoint of heat resistance, moisture resistance and storage stability, and two or more curing agents may be used in combination depending on the application.

In the present invention, the compounding amount of the curing agent (B) is usually 0.5 to 15 with respect to the entire epoxy resin composition.
% By weight, preferably 1 to 10% by weight. Further, the mixing ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of (B) to (A) is 0.5 to 1.5, particularly 0, from the viewpoint of mechanical properties and moisture resistance reliability. It is preferably in the range of 0.8 to 1.2.

In the present invention, a curing accelerator (C) is used to accelerate the curing reaction between the epoxy resin (A) and the curing agent (B). The curing accelerator (C) is not particularly limited as long as it promotes a curing reaction between the epoxy resin (A) and the curing agent (B). For example, 2-methylimidazole,
Imidazole compounds such as 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, triethylamine, benzyldimethylamine, α-methylbenzyl Tertiary amine compounds such as dimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7, zirconium tetra Organometallic compounds such as methoxide, zirconium tetrapropoxide, tetrakis (acetylaceto) zirconium, tri (acetylaceto) aluminum and triphenylphosphine, trimethylphosphine, triethylphosphine, trib Le phosphine, tri (p- methylphenyl) phosphine, an organic phosphine compound such as tri (nonylphenyl) phosphine and the like. Among them, an organic phosphine compound is preferably used from the viewpoint of moisture resistance. Two or more of these curing accelerators (C) may be used in combination depending on the application, and the addition amount thereof is preferably in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the epoxy resin (A). .

Among these curing accelerators (C), those which are particularly preferably used in the present invention are those having excellent moldability (external voids), and which are represented by the following general formula (IV). And tetraphenyl borate.

[0023]

Embedded image As the filler (D) in the present invention, amorphous silica,
Crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, asbestos, glass fiber, etc., among which amorphous silica lowers the linear expansion coefficient It is blended as the filler of the present invention because it has a large effect of reducing the stress and is effective in reducing the stress.

The amorphous silica of the present invention, unlike crystalline silica, is an amorphous silica in which the constituent elements of silica, silicon and oxygen, are not regularly arranged and are not in a crystalline state. . Amorphous silica can be obtained, for example, by melting crystalline silica and then rapidly cooling it (fused silica). Amorphous silica has a smaller coefficient of linear expansion than crystalline silica and is effective in reducing stress.

The amorphous silica can be produced by any production method. For example, a method of melting crystalline silica,
Examples include a method of synthesizing from various raw materials.

The shape and particle size of the filler (D) in the present invention are not particularly limited, but the average particle size is from 3 μm to 40 μm.
The filler (D) preferably contains 50% by weight or more of spherical particles having a particle size of m or less from the viewpoint of fluidity. Here, the average particle diameter means a particle diameter (median diameter) at which the cumulative weight becomes 50%.

In the present invention, the proportion of (D) in the inorganic filler must be 83 to 95% by weight of the whole resin composition from the viewpoint of flame retardancy, fluidity, low stress and adhesion. Preferably it is 85 to 93% by weight.

In the present invention, it is preferable from the standpoint of reliability that the filler is previously surface-treated with a coupling agent such as a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent.

The silicone compound (E) in the present invention is a polyorganosiloxane, which is generally a polymer such as a dimethylsiloxane unit, a methylphenylsiloxane unit, a diphenylsiloxane unit, etc. Those containing components (preferably at least 60 mol%, more preferably at least 80 mol%) are preferably used. Hydrogen, ethyl group, hydroxyl group,
Those in which the side chains or terminals are substituted with other organic groups can be used arbitrarily. As the properties of the silicone compound (E), liquid, gum-like and crosslinked rubber-like ones are optionally used, but liquid ones are preferably used from the viewpoint of dispersibility. The molecular weight of the silicone compound (E) is arbitrary from a disiloxane structure to an infinite one due to crosslinking. Among them, those having a number average polymerization degree of 2 or more siloxane repeating units, 10,000 or less, 5000 or less, and 2000 or less are preferably used.

In the present invention, among these silicone compounds (E), an organically modified silicone compound having the structure of the following general formula (I) is contained as an essential component, and the moldability (outer void, inner void, package) It is necessary from the viewpoint of surface appearance).

[0031]

Embedded image (Where 0 ≦ x ≦ 1000, 0 ≦ y ≦ 300, 0 ≦ z ≦
300, 0 ≦ x + y + z ≦ 1300. R and R 'are an alkyl group or alkylene group having 1 to 10 carbon atoms, and the hydrogen of the alkyl group may be substituted with a hydroxyl group or an alkyl group. Further, 0 ≦ a ≦ 50, 0 ≦ b ≦ 5
0. Among the organically modified silicone compounds having the structure of the general formula (I), the organically modified silicone compound having a polyether side chain is preferably used because of its excellent compatibility with the epoxy resin.

The amount of the silicone compound (E) in the present invention is preferably 0.01 to 0.01% based on the whole resin composition.
-5% by weight, more preferably 0.03-3% by weight. When the amount is 0.01% by weight or more, the effect of reducing external voids and internal voids is sufficiently exhibited.
If it is at most% by weight, the adhesion and the moldability (package surface appearance) will not be reduced.

The epoxy resin composition of the present invention comprises a flame retardant such as a halogen compound such as a halogenated epoxy resin;
Various flame retardant aids such as antimony trioxide, coloring agents such as carbon black, ion scavengers such as hydrotalcite, olefin copolymers, elastomers such as modified nitrile rubber and modified polybutadiene rubber, and thermoplastic resins such as polyethylene , Long chain fatty acids, metal salts of long chain fatty acids,
Release agents such as esters of long-chain fatty acids, amides of long-chain fatty acids, and paraffin wax, and crosslinking agents such as organic peroxides can be optionally added.

The epoxy resin composition of the present invention is preferably produced by melt-kneading. For example, the epoxy resin composition is melt-kneaded using a known kneading method such as a Banbury mixer, a kneader, a roll, a single- or twin-screw extruder and a co-kneader. It is manufactured by

Here, the semiconductor device refers to an electronic circuit (integrated circuit) formed by integrating transistors and diodes, resistors, capacitors, and the like on a semiconductor chip or substrate and wiring them. Refers to an electronic component sealed with a resin composition. Then, a semiconductor device can be obtained by sealing a semiconductor element formed of a semiconductor chip using the epoxy resin composition of the present invention.

As a method of manufacturing a semiconductor device, for example,
With the semiconductor element fixed to the lead frame, the epoxy resin composition of the present invention is molded at a temperature of, for example, 120 to 250 ° C., preferably 150 to 200 ° C. by a method such as transfer molding, injection molding, or casting. Thereby, a semiconductor device sealed with a cured product of the epoxy resin is manufactured. Further, if necessary, an additional heat treatment (for example, 150 to 200 ° C., 2 to 16 hours) can be performed.

[0037]

The present invention will be described below in detail with reference to examples. Incidentally,% in the examples indicates% by weight.

EXAMPLES AND COMPARATIVE EXAMPLES The raw material components shown in Table 1 were dry-blended by a mixer at the composition ratios shown in Table 2. This was heated and kneaded for 5 minutes using a mixing roll having a roll surface temperature of 90 ° C.
It was cooled and pulverized to produce an epoxy resin composition for semiconductor encapsulation.

Using this resin composition, a 160-pin QFP (quad flat package) mounted with a silicon chip (size 10 mm × 10 mm) having a surface of silicon nitride at 175 ° C. and a cure time of 2 minutes by a low-pressure transfer molding method. After molding, the characteristics of each resin composition were evaluated by the following characteristic evaluation method.

Adhesion: 16 pieces of the above 160-pin QFP were molded under the above conditions, and after post-curing at 175 ° C. for 4 hours,
Humidification was performed at 85 ° C./85% RH for 4 days, and the number of packages having peeled off on the chip surface was examined.

External void: The above 160 pin QFP is added to 1
Six were molded under the above conditions, and the number of external voids on the package surface was observed under a microscope. According to the total number of external voids observed (total number in 16 packages), the following A
ＥE was evaluated on a five-point scale. A: 0 to 1 (pieces / package 16) B: 2 to 5 (pieces / package 16) C: 6 to 10 (pieces / package 16) D: 11 to 15 (pieces / package 16) E: 16 or more (pieces) / 16 package)

Internal void: The above 160-pin QFP was converted to 4
The individual pieces were molded under the above conditions, and the internal voids inside the package were observed with an ultrasonic flaw detector. The average of the number of internal voids (pieces / package) observed in each package was evaluated in the following five grades A to E. A: 0 to 10 (pieces / package) B: 11 to 20 pieces / package C: 21 to 30 (pieces / package) D: 31 to 40 (pieces / package) E: 41 or more (pieces / package)

Package surface appearance: 160 pin Q above
Eight FPs were molded under the above conditions, and the package surface was visually checked for defects such as flow marks and seepage. The evaluation was performed in the following three stages. ：: good △: flow mark, slight seepage ×: poor (many flow marks, seepage)

[0044]

[Table 1]

[0045]

[Table 2]

As can be seen from Table 2, the epoxy resin compositions of the present invention (Examples 1 to 8) exhibited excellent adhesiveness, external voids,
Excellent internal voids and package surface appearance. On the other hand, Comparative Example 1 containing only dimethylpolysiloxane as the silicone compound is inferior in adhesion and package surface appearance. Comparative Example 2 containing no silicone compound is inferior in outer voids and internal voids, and Comparative Example 3 containing a large amount is inferior in adhesion and package surface appearance. Further, Comparative Example 4 in which the filler amount was less than 83% by weight was inferior in adhesion, and Comparative Example 5 in which the filler amount was more than 95% by weight had internal voids,
It turns out that it is inferior to an external void.

[0047]

According to the present invention, an epoxy resin composition for semiconductor encapsulation having excellent solder heat resistance (adhesion) and moldability (external voids, internal voids, package surface appearance) can be obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 63/00 C08L 63/00 AC H01L 23/29 H01L 23/30 R 23/31 F term (reference) 4J002 CC04X CD00W CD05W CD11Y CP08Y CP09Y CP18Y DK008 EW178 FD016 FD14X FD147 FD158 GQ05 4J036 AA01 AA05 AD07 AD08 AJ01 AJ02 AJ03 AJ15 AJ17 AJ21 DA04 FA01 FB07 FB16 JA07 4M109 AA01 EA04 EB04 EB19 EC05

Claims (5)

[Claims] 1. An epoxy resin (A), a curing agent (B), a curing accelerator (C), a filler (D), and a silicone compound (E) as essential components, and the content of the filler (D). Is 83 to 95% by weight based on the whole resin composition, the silicone compound (E) contains an organically modified silicone compound having a structure of the following formula (I) as an essential component, and further contains the silicone compound (E) Is 0.01 to the entire resin composition
An epoxy resin composition for semiconductor encapsulation, which is 5% by weight. Embedded image (Where 0 ≦ x ≦ 1000, 0 ≦ y ≦ 300, 0 ≦ z ≦
300, 0 ≦ x + y + z ≦ 1300. R and R 'are an alkyl group or alkylene group having 1 to 10 carbon atoms, and the hydrogen of the alkyl group may be substituted with a hydroxyl group or an alkyl group. Further, 0 ≦ a ≦ 50, 0 ≦ b ≦ 5
0. ) 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy resin (A) contains a biphenyl type epoxy resin having a structure of the following formula (II) as an essential component. Embedded image (However, R ₁ in the formula represents a hydrogen atom, an alkyl group or a halogen atom, and may be the same or different.) 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy resin (A) contains an epoxy resin having a structure represented by the following formula (III) as an essential component. . Embedded image (However, n in the formula is an integer of 0 to 5, and R ₂ represents a hydrogen atom, an alkyl group or a halogen atom, and may be the same or different.) 4. The method according to claim 1, wherein the curing accelerator (D) contains tetraphenylphosphonium tetraphenylborate having the structure of the following formula (IV) as an essential component. Epoxy resin composition for semiconductor encapsulation. Embedded image 5. A semiconductor device in which a semiconductor element is sealed with the epoxy resin composition according to claim 1.