JPH0786136B2 - Epoxy resin composition and semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an epoxy resin composition which has good storage stability and gives a cured product which is rapidly cured during heat molding to have excellent moisture resistance and the like. The present invention relates to a semiconductor device sealed with a cured product of the epoxy resin composition.

[Conventional technology]

As a package of a semiconductor device, an epoxy resin is widely used as a plastic, which gives a cured product having good electrical characteristics, mechanical characteristics, chemical resistance, moisture resistance and the like.
Above all, a resin composition in which a phenol resin is mixed with a novolac type epoxy resin as a curing agent and an inorganic filler is further added to the resin is currently the mainstream of resin encapsulation of semiconductor devices.

It is common to use a catalyst (curing accelerator) for accelerating the curing of the resin in the epoxy resin composition at the time of molding, and a nitrogen-containing or phosphorus-containing compound is used as the curing accelerator. .

[Problems to be Solved by the Invention]

However, generally used curing accelerators show a catalytic action even at a relatively low temperature depending on their type, and therefore, curing gradually occurs during heating and mixing of the epoxy resin and the curing agent and other components and subsequent storage. As it progresses, it may cause deterioration of moldability such as lowering of fluidity during molding and increase of viscosity, which may cause deterioration of electromechanical and chemical properties of molded products due to variation of curability. However, there is a problem that temperature control during mixing and storage of the epoxy resin composition must be strictly performed. Therefore, it is desired to develop an epoxy resin composition that is stable at room temperature, has good storage stability, and quickly cures during heat molding.

The present invention has been made in view of the above circumstances, and an epoxy resin composition having good storage stability and rapidly curing during heat molding to give a cured product having excellent properties especially for semiconductor encapsulation. Another object of the present invention is to provide a highly reliable semiconductor device sealed with a cured product of the epoxy resin composition.

[Means and Actions for Solving the Problems]

The present inventor has conducted extensive studies in order to achieve the above object, and as a result, (A) an epoxy resin, (B) a phenolic curing agent, and (C) an epoxy resin composition containing an inorganic filler, and further (D) ) As a curing accelerator, the following general formula (1) (In the formula, R ¹ , R ² and R ³ are the same or different substituted or unsubstituted monovalent hydrocarbon groups.) When the compound represented by the formula is added, the resulting epoxy resin composition has a long Even if stored for a period of time, there is little change in curability,
It has good storage stability, changes rapidly during thermoforming, and its cured product has good electrochemical properties, and the semiconductor device encapsulated with the cured product has excellent moisture resistance. The present invention has been found to be excellent in reliability and has led to the present invention.

Therefore, the present invention provides the above-mentioned component (A), component (B) and (C).
Provided are an epoxy resin composition, which comprises the component and the component (D) as essential components, and a semiconductor device sealed with a cured product of the epoxy resin composition.

Hereinafter, the present invention will be described in more detail.

The epoxy resin composition of the present invention is (A) as described above.
An epoxy resin, (B) a phenol-based curing agent, (C) an inorganic filler, and (D) a curing accelerator are added as essential components.

Here, the epoxy resin of the component (A) is not particularly limited as long as it has one epoxy group in one molecule, and for example, a bisphenol type epoxy resin, an alicyclic epoxy resin, a phenol novolac type epoxy resin. , Cresol novolac type epoxy resin, triphenol alkane type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, halogenated epoxy resin and the like are preferably used, and these may be used alone or in combination of two or more. Can be used.

In addition, it is desirable that the epoxy resin has a hydrolyzable chlorine content of 500 ppm or less, free Na and Cl ions of 2 ppm or less, and an organic acid content of 100 ppm or less from the viewpoint of moisture resistance of the composition. .

Next, examples of the phenolic curing agent as the component (B) include novolac type phenolic resins, resol type phenolic resins, triphenolalkane type resins, naphthol type resins, biphenyl type phenolic resins, and other phenolic resins. They may be used alone or in combination of two or more. The phenolic resin used as a curing agent contains free Na and Cl ions of 2 ppm or less each, the amount of phenol in the monomer is 1% or less, and formic acid generated by the Cannizzaro reaction of a small amount of formaldehyde remaining during production. It is desirable that the organic acid is 100 ppm or less, and if the content of free Na, Cl ions or organic acid in the phenol resin is more than the above amount, the moisture resistance property of the encapsulated semiconductor device may deteriorate. If the amount of phenol of the monomer in the phenol resin is more than 1%,
Defects such as voids, non-filling and sink marks may occur in the molded product. Furthermore, the softening point of phenol novolac resin is
50 to 120 ° C. is preferable, and if it is less than 50 ° C., the second transition point of the cured product may be low and the heat resistance may deteriorate.
If it exceeds 0 ° C, the melt viscosity of the composition becomes too high, which may result in poor workability.

In addition, in the epoxy resin composition of the present invention, (A)
As the curing agent for the epoxy resin as the component, the main component is the phenolic curing agent as the component (B), but if necessary, an amine curing agent represented by diaminodiphenylmethane, metaphenylenediamine, etc., pyromellitic anhydride. An acid anhydride curing agent such as an acid or benzophenonetetracarboxylic acid anhydride may be used in combination.

Here, the compounding amount of the curing agent is not particularly limited, but it is preferable that the molar ratio of the epoxy group of the epoxy resin to the phenolic hydroxyl group of the curing agent is 0.8 to 2, particularly 1 to 1.5. . If the molar ratio of both groups is less than 0.8, the curing characteristics of the composition and the second-order transition temperature of the molded article may be low, and the heat resistance may decrease, and if it is greater than 2, the second-order transition temperature and electrical characteristics of the molded article. May get worse.

As the inorganic filler of the component (C), in addition to fused silica and crystalline silica, silicon nitride, alumina, aluminum nitride, boron nitride, magnesium oxide, calcium carbonate, calcium silicate, zirconium, talc, clay, mica, glass fiber powder Are used.

As such an inorganic filler, various ones such as amorphous, sintered, and spherical can be used, but a spherical or near spherical shape is particularly preferable as the sealing material. Particularly in the case of alumina, the axial ratio between the major axis and the minor axis of the particles is 1 to 2, particularly 1 to 1 when observing the particles in a scanning electron micrograph.
It is preferably 7, and the use of alumina having an axial ratio of more than 2 may deteriorate the fluidity of the composition. The average particle size of the inorganic filler is preferably 5 to 50 microns, but the average particle size is within a range not exceeding 30% of the total amount of the filler.
You may use 1-5 micron thing. The amount of the inorganic filler contained in the resin is not particularly limited, but it is preferably 60% by weight or more of the entire resin composition.

The inorganic filler may be previously treated with a silane coupling agent or the like. In this case, as the silane coupling agent used for the treatment, a hydrolyzable residue-containing silane represented by the following structural formula (4) ▲ R ⁴ _4-c ▼ Si (OR ⁵ ) _c (4) Classes are preferably used.

In the above formula, R ⁵ is a hydrogen atom, a methyl group, an ethyl group,
Examples include non-functional alkyl groups such as propyl group and phenyl group, alkenyl groups, aryl groups, and those shown below, which have epoxy, amino, acryl, alkenyl and acyl functionalities.

_{H 2 NCH 2 CH 2 NHCH 2} CH 2 CH 2 - R 6 R 7 NCH 2 CH 2 CH 2 - R 6, R 7 = H, C d H 2d + 1, C 6 H 5 CH 2 d = 1~6 integer ^{_{CH 2 = C (R 8)}} COO (CH 2) n - R 8 = H, CH 3 n = 1~3 integer _{CH 2 = CH (CH 2)} m - m = 0~4 integer HOCO ( CH ₂ ) _l -l = integer of 2 to 18 On the other hand, R ⁵ includes an alkyl group, an alkenyl group, an aryl group, a carbonyl group and the like, and among them, a methyl group, an ethyl group, an isopropenyl group and the like are common. Target,
Although c is 1 to 4, it is more preferable that c is 3 or 4.

As a method for treating the inorganic filler with the silane coupling agent, either a dry method or a wet method may be used. The dry method is a ball mill, a Henschel mixer, or the like, and the wet method is a silane coupling agent for the inorganic filler in a solvent. Mixed,
It can be performed by stirring. The amount of the silane coupling agent is 0.001 to 8 parts, more preferably 0.01 to 5 parts based on 100 parts of the inorganic filler (parts by weight, the same applies below).
It is a range of parts. If the amount of the silane coupling agent is too small, the effect of the treatment, that is, the improvement of the moisture resistance is not exhibited, and if the amount of the silane coupling agent is too large, the burr characteristics may deteriorate rather. Two or more kinds of these silane coupling agents may be used in combination, and those partially hydrolyzed in advance may be used. Examples of the solvent used in the wet method include hydrocarbon solvents such as toluene and xylene, alcohol solvents such as methanol, ethanol and isopropyl alcohol, ketone solvents such as acetone and 2-butanone, and ether solvents such as isopropyl ether and tetrahydrofuran. It is also possible to use water and a tin-based, titanium-based, or amine compound as a hydrolysis accelerator together. After the treatment as described above, it is also possible to sinter in a heating furnace at about 400 to 1200 ° C.

The curing accelerator used as the component (D) in the epoxy resin of the present invention has the following formula (1) (Wherein R ¹ , R ² and R ³ are the same or different substituted or unsubstituted monovalent hydrocarbon groups, respectively).

Here, the substituted or unsubstituted monovalent hydrocarbon group of R ¹ , R ² and R ³ is preferably one having 1 to 10 carbon atoms, particularly one having 1 to 8 carbon atoms, such as a methyl group or an ethyl group. , Propyl group,
Alkyl groups such as butyl groups, or aryl groups such as chloromethyl groups in which some or all of the hydrogen atoms of these groups are replaced with halogen atoms, 3,3,3-trifluoropropyl groups, phenyl groups, tolyl groups, etc. And aralkyl groups such as benzyl group and phenethyl group,
Most commonly, R ¹ is a methyl group and a butyl group, a phenyl group, and R ² and R ³ are methyl groups.

The compound of the above formula (1) is a known substance obtained by reacting a corresponding tertiary phosphine with a corresponding phosphoric acid ester, and for example, reacting triphenylphosphine, tributylphosphine, etc. with dimethylmethanephosphonate, etc. Obtained by Specific examples of the compound of the formula (1) include methyltriphenylphosphonium methylmethanephosphonate, methyltributylphosphonium methylmethanephosphonate, and benzyltriphenylphosphonium benzylmethanephosphonate. One of these may be used alone or in combination of two or more. Can be used in combination.

In the epoxy resin of the present invention, other curing accelerators can be used in addition to the curing accelerator represented by the formula (1). In this case, especially 1,8-diazabicyclo (5.4.0)
Combined use with Undecene-7 is desirable from the viewpoint of curability, moisture resistance and the like. The compounding amount of the entire curing accelerator is preferably in the range of 0.1 to 10 parts, particularly 0.3 to 7 parts based on 100 parts of the total amount of the epoxy resin and the curing agent, and the curing amount represented by the formula (1) Accelerator is 10 to 100% by weight of the total curing accelerator, especially 20
It is preferable to be set to 100% by weight.

It is desirable to add a silicone-modified epoxy resin and / or a silicone-modified phenol resin to the epoxy resin composition of the present invention in order to further impart a low linear expansion coefficient, a low elastic modulus and good moisture resistance.

As the silicone-modified epoxy resin and phenol resin, the following formula (2) is added to the alkenyl group of the alkenyl group-containing epoxy resin or the alkenyl group-containing phenol resin. (However, in the formula, R ⁹ has the same number of carbon atoms as that of R ^{1 to} R ³ described above.
~ 10 substituted or unsubstituted monovalent hydrocarbon group, a,
b is a positive number that satisfies 0.01 ≦ a <1, 1 ≦ b <3, 1 ≦ a + b <4. The number of silicon atoms in one molecule is 20 to 400.
And the number of hydrogen atoms directly connected to a silicon atom in one molecule is an integer of 1 or more. A polymer obtained by adding an ≡SiH group of an organic silicon compound represented by (4) can be preferably used.

In this case, as the alkenyl group-containing epoxy resin or phenol resin, the following formula (3) (However, R ¹⁰ is Alternatively, a hydroxyl group, R ¹¹ is a methyl group or a hydrogen atom, and p and q are integers represented by 0 ≦ p ≦ 10 and 1 ≦ q ≦ 3. ) The alkenyl group-containing epoxy resin or phenol resin represented by

In this case, the silicone-modified epoxy resin or phenol resin has a hydrolyzable chlorine content of 500 ppm or less,
Free Na and Cl ions are less than 2ppm each, organic acid content is 100
It is preferably ppm or less, hydrolyzable chlorine, free Na, Cl ions, if the content of organic acids exceeds the above values,
The heat resistance of the sealed semiconductor device may deteriorate.

The silicone-modified epoxy resin or phenol resin may be used alone or as a mixture of two or more kinds, and the compounding amount is 5 to 50 parts based on 100 parts of the total amount of the epoxy resin and the curing agent. It is preferable. If the compounding amount of the silicone-modified epoxy resin is less than 5 parts, it is difficult to obtain a sufficiently low stress property, and if it exceeds 50 parts, the mechanical strength of the molded product may decrease.

Various additives can be further added to the composition of the present invention as necessary. For example, waxes such as carnauba wax, release agents such as fatty acids such as stearic acid and metal salts thereof (adhesiveness among others, Carnauba wax is preferably used from the viewpoint of releasing property), pigments such as carbon black, cobalt blue and red iron oxide, antimony oxide, flame retardants such as halogen compounds, antiaging agents, silane coupling agents, ion exchange materials. Can also be used as appropriate.
Incidentally, the epoxy resin composition of the present invention, in the production thereof, uniformly stirs and mixes predetermined amounts of the above-mentioned components, and kneads them with a kneader, roll, extruder or the like which has been heated to 60 to 95 ° C. in advance, and cools them. It can be obtained by a method such as crushing and crushing.

The epoxy resin composition of the present invention can be effectively used for resin encapsulation of semiconductors such as ICs, LSIs, transistors, thyristors, and diodes, and manufacturing of printed circuit boards. The epoxy resin composition of the present invention can be used for semiconductor devices. The resin encapsulation can be performed by a conventionally used molding method, such as transfer molding, injection molding, or casting method. Molding conditions are temperature 150-180
C. and post cure are preferably carried out at 150 to 180.degree. C. for about 2 to 16 hours.

〔The invention's effect〕

As explained above, the epoxy resin composition of the present invention,
It has excellent storage stability and is rapidly cured during heat molding to give a cured product having good electrochemical properties. Therefore, it is sealed with a cured product of the epoxy resin composition of the present invention. The manufactured semiconductor device has excellent moisture resistance and the like and is highly reliable.

Hereinafter, the present invention will be specifically described by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight.

Example 1 500 parts of crystalline silica (average particle size: 17 μm) was put in a Henschel mixer, and 0.02% by weight of 1,8-diazabicyclo-7 was added.
2.0 parts of γ-glycidoxypropyltrimethoxysilane containing undecene were sprayed on and dispersed homogeneously. Then, heat treatment was performed at 180 ° C. for 12 hours.

This inorganic filler, and 20 parts of silicone-modified epoxy resin (subscript in the formula is the average value, epoxy equivalent 295) which is an addition reaction product with cresol novolac type epoxy resin (epoxy equivalent 230) 13
Part, naphthol type epoxy resin (epoxy equivalent 215) 30
Parts, brominated epoxy resin (epoxy equivalent 280) 5 parts, phenol novolac resin (phenol equivalent 110) 32 parts,
Carnauba wax 1.2 parts, γ-glycidoxypropyltrimethoxysilane 1.8 parts, carbon black 2 parts, methyltriphenylphosphonium methylmethanephosphonate
0.95 parts and 1,8-diazabicyclo-7-undecene 0.1
Eight parts were put on a hot roll at 80 to 90 ° C, kneaded, cooled and pulverized to obtain an epoxy resin.

Example 2 An epoxy resin composition was obtained in the same composition as in Example 1 except that 0.95 part of methyltriphenylphosphonium methylmethanephosphonate in Example 1 was replaced with 0.80 part of methyltributylphosphonium methylmethanephosphonate.

Example 3 0.74 parts of methyltriphenylphosphonium methylmethanephosphonate in Example 1, 1,8-diazabicyclo-
An epoxy resin composition was obtained in the same formulation as in Example 1 except that 0.18 part of 7-undecene was replaced with 2.48 parts of methyltriphenylphosphonium methylmethanephosphonate alone.

[Example 4] The inorganic filler in Example 1 was fused silica (average particle size).
An epoxy resin composition was obtained in the same formulation as in Example 1 except that only 22 μm) was replaced with 370 parts.

[Example 5] Except that the inorganic filler in Example 1 was replaced with 550 parts of α-alumina (average particle size 25 µm) treated in the same manner as in Example 1 and 110 parts of fused silica (average particle size 1.2 µm). An epoxy resin composition was obtained with the same composition as in Example 1.

Example 6 Example 1 was repeated except that the inorganic filler in Example 1 was replaced by 500 parts of spherical alumina (average particle size 15 μm) treated in the same manner as in Example 1 and 100 parts of fused silica (average particle size 25 μm). An epoxy resin composition was obtained with the same composition.

[Comparative Example 1] 2.48 parts of the compound methyltriphenylphosphonium methylmethanephosphonate in Example 3 was replaced with 2-ethyl-4-
An epoxy resin composition was obtained in the same formulation as in Example 1 except that 0.64 parts of methylimidazole was used.

Comparative Example 2 An epoxy resin composition was obtained in the same composition as in Example 1 except that 0.95 parts of the compound methyltriphenylphosphonium methylmethanephosphonate in Example 1 was replaced with 0.60 parts of tris (4-methoxyphenylaphosphine). .

[Comparative Example 3] An epoxy resin composition was obtained in the same composition as in Example 1 except that 0.95 parts of the compound methyltriphenylphosphonium methylmethanephosphonate in Example 1 was replaced with 1.15 parts of triphenylphosphine triphenylborate.

Comparative Example 4 0.95 parts of the compound methyltriphenylphosphonium methylmethanephosphonate in Example 6 and 0.18 part of 1,8-diazabicyclo-7-undecene were added to 2phenylimidazole.
An epoxy resin composition was obtained with the same composition as in Example 6 except that 0.66 part was used.

Curability at the time of molding for these compositions, storage stability,
Bending strength, thermal shock resistance test, and humidity resistance of power IC (aluminum corrosion test) were evaluated by the following methods. The results are shown in Table 1.

Spiral flow value Using a mold conforming to the EMMI standard, it was measured immediately after compounding and after 90 days of storage at 10 ° C under the conditions of 175 ° C and 70 kg / cm ² .

Hardness Using a transfer molding machine, the hot hardness after molding at 175 ° C./70 kg · cm ⁻² for 2 minutes was measured using a Barcol hardness meter 935.

Measuring method of aluminum wiring corrosion rate Designed to study the corrosion of aluminum metal electrodes
A 14-pin IC was molded with an epoxy resin composition by a transfer molding method, and then placed in a high-pressure oven at 125 ° C. and a humidity of 85% for 15 hours with a bias voltage of 15 V for 250 hours, and the open defect rate of the wiring was examined.

From the results shown in Table 1, the epoxy resin composition of the present invention containing the curing accelerator represented by the formula (1) (Example) is an epoxy resin composition containing no curing accelerator (Comparative Example).
Compared with, the curability is good and the storage stability is good. Further, it is recognized that the epoxy resin composition of the present invention gives a cured product having an excellent semiconductor protection function, and an IC encapsulated with such a cured product has excellent moisture resistance.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01L 23/29 23/31 (72) Inventor Seiji Katayama 2-13-1 Isobe, Annaka-shi, Gunma Shin-Etsuka Gakukogyo Co., Ltd. Silicone Electronic Materials Research Laboratory (56) Reference JP-A-2-163115 (JP, A) JP-A-58-119654 (JP, A) JP-A-57-194555 (JP, A) Kai 48-47994 (JP, A)

Claims (2)

[Claims] 1. (A) Epoxy resin, (B) Phenolic curing agent, (C) Inorganic filler, (D) The following general formula (1) (In the formula, R ¹ , R ² and R ³ are the same or different substituted or unsubstituted monovalent hydrocarbon groups.) A curing accelerator is added as an essential component. And an epoxy resin composition. 2. A semiconductor device encapsulated with a cured product of the epoxy resin composition according to claim 1.