JPH1121427A - Epoxy resin molding material for sealing electronic part and electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both an epoxy resin composition, excellent in moldability and reliability and effective in even suppression of the peeling of an oxide film of a copper-based lead frame and an epoxy resin molding material for sealing electronic parts. SOLUTION: This epoxy resin composition consists essentially of (A) an epoxy resin, (B) a curing agent, (C) a silane coupling agent and (D) an inorganic filler. The silane coupling agent of the component C is represented by the formula [R<1> is hydrogen, a 1-6C alkyl group or a 1-2C alkoxy group; R<2> is a 1-6C alkyl group or phenyl group; R<3> is methyl group or ethyl group; (n) denotes a number of 1-6]. The epoxy resin molding material for sealing electronic parts contains the resin composition.

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 moldability and reliability, an epoxy resin molding material for encapsulating electronic components, and an electronic component in which elements are encapsulated with the molding material.

[0002]

2. Description of the Related Art Conventionally, in the field of element sealing of electronic components such as transistors and ICs, resin sealing has become the mainstream in terms of productivity and cost, and epoxy resin molding materials have been widely used. The reason for this is that the epoxy resin is well balanced in various properties such as workability, moldability, electrical properties, moisture resistance, heat resistance, mechanical properties, and adhesion to insert products. Further, as a lead frame for mounting an element and ensuring electrical contact with the outside, an iron-based material has been mainly used for a surface mounting package.

In recent years, products using a copper-based lead frame have been increasing in terms of heat dissipation and cost. However, the copper-based lead frame has advantages in heat dissipation and cost, but has the disadvantage that an oxide film is easily formed on the surface and the strength of the oxide film is extremely low. Therefore, an oxide film is formed on the surface of the lead frame by heat applied in a step of fixing the element to the lead frame, a step of connecting the element and the lead frame with a gold wire, and the like. When such a lead frame having an oxide film formed on the surface is sealed with a conventional epoxy resin molding material for sealing electronic components, the oxide film peels off due to stress generated at the interface between the lead frame and the molding material. The reliability as an electronic component was significantly reduced.

[0004] Various countermeasures have been studied for this problem. For example, a step of fixing the element to a lead frame,
There is a method in which the step of connecting the element and the lead frame with a gold wire or the like is performed in a nitrogen atmosphere or at a relatively low temperature to suppress formation of an oxide film and prevent peeling. These techniques are effective in preventing the separation of the oxide film, but are not practical in terms of cost and connection strength of the gold wire. A method of improving the heat resistance by coating the surface of the copper frame with plating is also effective, but is not practical in terms of cost.

[Problems to be solved by the invention]

On the other hand, as improvements from the epoxy resin molding material for encapsulating electronic parts, it has been proposed to add a flexibilizing agent, optimize the amount of filler, and review the release agent.
There is no reliability that meets the requirements of electronic component sealing applications. It has already been reported that an epoxy resin composition using a coupling agent containing two alkoxy groups and a γ-glycid group has low corrosiveness to aluminum (JP-A-60-179419). However, this limits the functional group to a γ-glycidic group, and does not mention improvement in adhesion to copper.

In view of the above background, the present invention strongly demands an epoxy resin molding material for encapsulating electronic parts, which has the same reliability and moldability as copper-based lead frames as well as iron-based lead frames. Have been.

[Means for Solving the Problems]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that the addition of a specific coupling agent has a remarkable effect in suppressing the separation of an oxide film from a copper-based lead frame. As a result, it was found that a molding material satisfying the above requirements was obtained, and the present invention was completed.

That is, the present invention comprises (1) (A) an epoxy resin, (B) a curing agent, (C) a silane coupling agent, and (D) an inorganic filler as essential components, and (C) a silane component. An epoxy resin composition, wherein the coupling agent is represented by the following general formula (I):

Embedded image (Where R ¹ is hydrogen or an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to ² carbon atoms;
6, an alkyl group or phenyl group, R ³ is a methyl group or an ethyl group, and n represents a number of 1 to 6. (2) The epoxy resin composition according to the above (1), comprising a silane compound represented by the following general formula (II):

(R ¹ ) ₂ —Si— (OR ² ) ₂ (II) (where R ¹ is an alkyl group or phenyl group having 1 to 10 carbon atoms, and R ² is a methyl group or ethyl (3) The epoxy resin composition according to the above (1) or (2), further comprising an epoxy resin represented by the following general formula (III):

Embedded image (Here, R ^{1 to} R ⁴ represent hydrogen or a hydrocarbon having 1 to 10 carbon atoms, and may be the same or different. N represents a positive number of 0 to 3.) (4) The following general formula: The epoxy resin composition according to any one of the above (1) to (3), comprising a curing agent of the formula (IV):

Embedded image (Where R is hydrogen, a hydrocarbon having 1 to 10 carbon atoms or halogen, and n represents a positive number of 0 to 8). (5) The epoxy resin according to any one of the above (1) to (4) An epoxy resin molding material for encapsulating an electronic component, comprising a composition, and (6) an electronic component obtained by encapsulating an element with the molding material according to (5).

[0009]

DETAILED DESCRIPTION OF THE INVENTION (A) used in the present invention
The epoxy resin of the component is not particularly limited, and is, for example, one generally used in an epoxy resin molding material for encapsulating electronic parts, and is a phenol novolak type epoxy resin, an orthocresol novolak type epoxy resin, a bisphenol A novolak type. Epoxy resins obtained by epoxidizing novolak resins synthesized from phenols and aldehydes including epoxy resins, diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol S, and alkyl-substituted biphenols; polyamines such as diaminodiphenylmethane and isocyanuric acid Glycidylamine type epoxy resin obtained by the reaction of phenol and epichlorohydrin, epoxidized co-condensation resin of dicyclopentadiene and phenols, epoxy resin having naphthalene ring, naphtho Epoxidized aralkyl resins, trimethylolpropane-type epoxy resins, terpene-modified epoxy resins, linear aliphatic epoxy resins obtained by oxidizing olefin bonds with a peracid such as peracetic acid, and alicyclic epoxy resins. From the viewpoint of reflow resistance, an epoxy resin represented by the following general formula (III) is preferable.

Embedded image (Here, R ^{1 to} R ⁴ represent hydrogen or a hydrocarbon having 1 to 10 carbon atoms and may be the same or different from each other. N represents a positive number of 0 to 3.) Epoxy containing 4,4'-bis (2,3-epoxypropoxy) biphenyl or 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetramethylbiphenyl as a main component Resin, epichlorohydrin and 4,4'-bis (2,3-epoxypropoxy) biphenol or 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetramethylbiphenol An epoxy resin obtained by the reaction is exemplified. Among them, an epoxy resin containing 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylbiphenyl as a main component is preferable. These epoxy resins can be used alone or in combination of two or more.

The curing agent of the component (B) used in the present invention is not particularly limited. For example, a curing agent generally used in an epoxy resin molding material for sealing electronic parts, such as phenol, cresol, resorcin, catechol, Resins obtained by condensing or co-condensing phenols such as bisphenol A and bisphenol F or naphthols such as α-naphthol, β-naphthol and dihydroxynaphthalene with aldehydes such as formaldehyde in the presence of an acidic catalyst, phenol aralkyl resins And a naphthol aralkyl resin, and particularly from the viewpoint of reflow resistance, a phenol aralkyl resin represented by the following general formula (IV) is preferable.

Embedded image (Here, R is hydrogen, a hydrocarbon having 1 to 10 carbon atoms or halogen, and n represents a positive number of 0 to 8.) Above all, it is represented by the following formula (V), and n is 0 on average. To 8 are preferred.

Embedded image These curing agents can be used alone or in combination of two or more.

The epoxy resin (A) and the epoxy resin (B)
The equivalent ratio of the curing agent of the component, that is, the ratio of the number of epoxy groups in the epoxy resin / the number of hydroxyl groups in the curing agent is not particularly limited, but is 0.7 to 1.3 in order to reduce the amount of each unreacted component. In particular, in order to obtain a molding material having excellent moldability and reflow resistance, it is preferably set in the range of 0.8 to 1.2.

The silane coupling agent of the component (C) used in the present invention is represented by the following general formula (I).

Embedded image (Where R ¹ is hydrogen or an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to ² carbon atoms;
6, an alkyl group or phenyl group, R ³ is a methyl group or an ethyl group, and n represents a number of 1 to 6. For example, γ-anilinopropylmethyldimethoxysilane, γ-anilinopropylmethyldiethoxysilane, γ-anilinomethylmethyldimethoxysilane, γ
-Anilinomethylmethyldiethoxysilane, N- (p-
Methoxyphenyl) -γ-aminopropylmethyldimethoxysilane, N- (p-methoxyphenyl) -γ-aminopropylmethyldiethoxysilane, and the like. From the viewpoint, γ-anilinopropylmethyldimethoxysilane is preferably used.

The compounding amount of the silane coupling agent of the component (C) is 0.2 to 5.0 with respect to the inorganic filler of the component (D).
% By weight, more preferably 0.5% by weight.
~ 2.5% by weight. If it is less than 0.2% by weight, the adhesion to the frame tends to decrease, and if it exceeds 5.0% by weight, the moldability of the package tends to decrease.

In the epoxy resin composition of the present invention and the epoxy resin molding material for encapsulating electronic parts, a conventionally known coupling agent may be used in addition to the silane coupling agent of the component (C). For example, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyl Trimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ
-Aminopropyltriethoxysilane, γ- [bis (β
-Hydroxyethyl)] aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, γ- (β-aminoethyl) aminopropyldimethoxymethylsilane, N- (trimethoxysilylpropyl) Ethylenediamine, N- (dimethoxymethylsilylisopropyl) ethylenediamine, methyltrimethoxysilane, methyltriethoxysilane, N
-Β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, γ-mercaptopropyl Silane-based coupling agents such as methyldimethoxysilane, or isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, tetraoctyl bis (ditridecyl phosphite) titanate Tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, Bis (dioctyl pyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearyl diacryl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, One or more titanate coupling agents such as tetraisopropylbis (dioctylphosphite) titanate can be used in combination.

The inorganic filler of the component (D) in the present invention is not particularly limited, but may be fused silica, crystalline silica,
Powders of alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, aluminum nitride, boron nitride, beryllia, zirconia, etc., or spherical beads of these, single crystals of potassium titanate, silicon carbide, silicon nitride, alumina, etc. One or more kinds of fibers, glass fibers and the like can be used in combination. Further, examples of the inorganic filler having a flame-retardant effect include aluminum hydroxide, magnesium hydroxide, zinc borate and the like, and these can be used alone or in combination. Among the above-mentioned inorganic fillers, fused silica is preferred from the viewpoint of reducing the linear expansion coefficient, and alumina is preferred from the viewpoint of high thermal conductivity. The shape of the filler is preferably spherical or nearly spherical in view of fluidity during molding and mold abrasion, and particularly preferably 50% by weight or more is spherical.

The amount of the inorganic filler (D) is preferably 70% by weight or more, more preferably 85% to 95% by weight, based on the whole molding material, from the viewpoints of hygroscopicity, reduction of linear expansion coefficient and improvement of strength.
Is particularly preferred. If it is less than 85% by weight, the reflow resistance tends to decrease, and if it exceeds 95% by weight, the fluidity tends to be insufficient. Among them, the range of 88 to 92% by weight is more preferable.

The epoxy resin composition and the epoxy resin molding material for encapsulating electronic parts of the present invention include the above (A) to
In addition to the component (D), a silane compound represented by the following general formula (II) can be used.

Embedded image (R ¹ ) ₂ —Si— (OR ² ) ₂ (II) (where R ¹ is an alkyl group or phenyl group having 1 to 10 carbon atoms, and R ² is a methyl group or ethyl Represents a group.)
The silane compound of the general formula (II) is effective for suppressing oxide film separation and improving solder heat resistance. Examples thereof include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, and methylphenyldiethoxysilane, among which dimethyldimethoxysilane is particularly preferred.

The compounding amount of the silane compound of the general formula (II) is
The ratio ((C) / (II)) to the component (C) is preferably set to 0.5 to 10, more preferably 1 to 5. If it is less than 0.5, the adhesion to the frame tends to decrease, and if it exceeds 10, the moisture resistance reliability tends to decrease.

A curing accelerator can also be used in the epoxy resin composition of the present invention and the epoxy resin molding material for sealing electronic parts. For example, 1,8-diaza-bicyclo (5,4,0) undecene-7,1,5-diaza-bicyclo (4,3,0) nonene, 5,6- {butylamino-
1,8-diaza-bicyclo (5,4,0) undecene-
7, benzyldimethylamine, triethanolamine,
Tertiary amines such as dimethylaminoethanol and tris (dimethylaminomethyl) phenol and derivatives thereof, imidazoles such as 2-methylimidazole, 2-phenylimidazole and 2-phenyl-4-methylimidazole and derivatives thereof, tributyl Phosphine,
Organic phosphines such as methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine, and intramolecular polarization obtained by adding compounds having a π bond such as maleic anhydride, benzoquinone, and diazophenylmethane to these phosphines Examples include phosphorus compounds, tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, N-methylmorpholine tetraphenylborate, and derivatives thereof. Can be These may be used alone or in combination of two or more.

Further, as other additives, flame retardants such as brominated epoxy resins, antimony trioxide, phosphate esters, red phosphorus and melamine resins, and other nitrogen-containing compounds, natural waxes, synthetic waxes, oxidized or non-oxidized Release agents such as oxidized polyolefins, coloring agents such as carbon black, stress relievers such as silicone oil and silicone rubber powder, and ion trapping agents such as hydrotalcite and antimony-bismuth can be used as necessary. .

The molding material in the present invention can be prepared by any method as long as various raw materials can be uniformly dispersed and mixed. As a general method, a predetermined amount of raw materials are thoroughly mixed by a mixer or the like. After mixing, melt-kneading with a mixing roll, extruder, etc., cooling,
A pulverizing method can be used. It is easy to use if it is tableted with dimensions and weight that match the molding conditions.

Supporting members such as lead frames, wired tape carriers, wiring boards, glass, silicon wafers, and the like, active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils. An electronic component can be manufactured by mounting the element and sealing a necessary portion with the molding material for sealing of the present invention. Such electronic components include, for example, copper reeds.
Examples include QFP in which a chip mounted on a do frame is sealed with the molding material of the present invention, and TCP in which a semiconductor chip connected to a tape carrier by a bump is sealed with the molding material of the present invention. Also, active elements such as semiconductor chips, transistors, diodes, thyristors, and / or passive elements such as capacitors, resistors, and coils are connected to wiring formed on a wiring board or glass by wire bonding, flip chip bonding, soldering, or the like. , A COB module, a hybrid IC, a multi-chip module, and the like, which are sealed with the molding material of the present invention. As a method of sealing the electronic component, a low-pressure transfer molding method is the most common, but an injection molding method, a compression molding method, or the like may be used.

[0023]

EXAMPLES Next, examples of the present invention will be described, but the scope of the present invention is not limited to these examples.

Examples 1 and 2, Comparative Examples 1 to 3 After premixing (dry blending) each material with the composition shown in Table 1, a biaxial roll (roll surface temperature of about 80 ° C.)
For 10 minutes, and cooled and pulverized to produce molding materials of Examples 1 and 2 and Comparative Examples 1 to 3. Examples of the epoxy resin include an epoxy resin (1) mainly composed of 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylbiphenyl having an epoxy equivalent of 196; An epibis-type brominated epoxy resin having an equivalent weight of 393 and a bromine content of 49% is used.
171 hydroxyl equivalents, 69 ° C softening point, 900 number average molecular weight
The phenol aralkyl resin of the following structural formula (V) was used.

Embedded image (Here, n indicates a positive number from 0 to 8.)

[0025]

[Table 1] Table 1 Composition (unit: parts by weight) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Material Example Comparative Example 1 2 1 2 3 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Epoxy resin (1) 85 85 85 85 85 Brominated epoxy resin 15 15 15 15 15 Phenol resin 85 85 85 85 85 85 Triphenylphosphine 2 2 2 2 2 N-phenyl-γ-aminopropyl 10 10 − − − Methyldimethoxysilane γ-glycidoxypropyl -10 10 10 Trimethoxysilane Dimethyldimethoxysilane-5-5- Flexible agent-----20 (Polydimethylsiloxane) Carnauba wax 1 1 1 1 1 Polyethylene wax 1 1 1 1 1 Antimony trioxide 55 55 55 Carbon black 3.5 3.5 3.5 3.5 3.5 Fused silica (spherical) 1700 1700 1700 1700 17
00 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Using the transfer molding machine, a total of five types of molding materials were evaluated by conducting the following tests under the conditions of a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm ² , and a curing time of 90 seconds. (1) Spiral flow (indicator of fluidity) Molding was performed using a mold for measuring spiral flow according to EMMI-1-66, and the flow distance was determined. (2) Hot hardness The hardness of the molded product immediately after opening the mold was measured using a Shore-D hardness meter. (3) Moisture Resistance A SOP-28 pin semiconductor device was molded using each molding material, and cured at 175 ° C. for 5 hours to produce a test package. 85 ° C / 85% for this package
After pretreatment of RH / 72 hours moisture absorption + 215 ° C./90 seconds (VPS), it is left in PCT (121 ° C./2 atm) to observe the presence or absence of disconnection of wiring on the chip, and until the disconnection failure rate reaches 50%. I checked the time. (4) Solder heat resistance QFP 80-pin resin-sealed semiconductor device (external dimensions 20
mm × 14mm × 2mm, chip size: 8 × 10m
m, using a lead frame: EFTEC64T (without stage processing)), bonding a silicon chip to the frame with a silver paste (130 ° C./2 hr curing),
An oxide film was formed on the surface of the frame by being left on a hot plate maintained at 25 ° C. for 3 minutes. This frame was formed using the molding materials of Examples and Comparative Examples, with a mold temperature of 180 ° C. and a molding pressure of 7.
Molded under the conditions of 0 kgf / cm ² and curing time of 90 seconds.
A test package was prepared by curing at 75 ° C. for 5 hours. This package was placed in a thermo-hygrostat, 85
After absorbing moisture for a predetermined time under the conditions of
The presence or absence of cracks when treated under the conditions of ° C./10 seconds was observed, and the moisture absorption time until cracks were generated was examined. (5) Oxide film peeling The test package created in (4) above, after post-curing,
The presence or absence of peeling on the back surface of the stage was observed using an ultrasonic probe, and evaluated by the peeling area ratio (%). Table 2 shows the evaluation results.

[0027]

[Table 2] Table 2 Evaluation results 項 Item Example Comparative example 1 2 1 2 3 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Spiral flow (inch) 35 40 30 35 30 Heat hardness 80 80 83 83 75 Moisture resistance (hr) 1350 1400 1250 1050 1450 Solder heat resistance (hr) 120 168 24 48 48 Oxide film peeling (%) <100> 30 10-30 <10 Molded product appearance good Good good good bad ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

In each of the comparative examples containing no silane coupling agent (C) in the present invention, the solder heat resistance is inferior. In Comparative Examples 1 and 2, the oxide film peeling was further large and the moisture resistance was poor. In Comparative Example 3 in which a flexibilizing agent was added, although the effect of preventing peeling was observed, the hardness when heated (moldability) was low and the appearance was poor. On the other hand, Examples 1 and 2, which contain all of the components (A) to (D), had good fluidity, hardness at heat, moisture resistance, solder heat resistance, and appearance, and also had an effect of preventing peeling. . In particular, in Example 2 in which the silane compound corresponding to the general formula (II) was added, no oxide film peeling was observed at all.

[0029]

The epoxy resin molding material for encapsulating electronic parts obtained by the present invention is excellent in reliability such as fluidity and moldability, so that it contributes to high productivity of electronic parts.
Using this molding material, a semiconductor device manufactured by sealing a semiconductor element mounted on a copper-based lead frame is excellent in moisture resistance and solder heat resistance as shown in the examples, and oxide film peeling is suppressed. Therefore, its industrial value is great.

Claims (6)

[Claims] (1) an epoxy resin, (B) a curing agent,
An epoxy resin composition comprising (C) a silane coupling agent and (D) an inorganic filler as essential components, wherein the silane coupling agent as the component (C) is represented by the following general formula (I). Stuff. Embedded image (Where R ¹ is hydrogen or an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to ² carbon atoms;
6, an alkyl group or phenyl group, R ³ is a methyl group or an ethyl group, and n represents a number of 1 to 6. ) 2. The epoxy resin composition according to claim 1, comprising a silane compound represented by the following general formula (II). (R ¹ ) ₂ —Si— (OR ² ) ₂ (II) (where R ¹ is an alkyl group having 1 to 10 carbon atoms or a phenyl group, and R ² is a methyl group or ethyl Represents a group.) 3. The epoxy resin composition according to claim 1, comprising an epoxy resin represented by the following general formula (III). Embedded image (Here, R ^{1 to} R ⁴ represent hydrogen or a hydrocarbon having 1 to 10 carbon atoms and may be the same or different. N represents a positive number of 0 to 3.) 4. The epoxy resin composition according to claim 1, further comprising a curing agent represented by the following general formula (IV). Embedded image (Here, R is hydrogen, a hydrocarbon having 1 to 10 carbon atoms or halogen, and n is a positive number of 0 to 8.) 5. An epoxy resin molding material for sealing electronic parts, comprising the epoxy resin composition according to claim 1. 6. An electronic component obtained by sealing an element with the molding material according to claim 5.