JPH082943B2 - Epoxy resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition that is preferably used for molding materials, semiconductor encapsulation, and the like.

2. Description of the Related Art As a semiconductor device package, an epoxy resin composition that gives a cured product having good electrical characteristics, mechanical characteristics, chemical resistance, moisture resistance, etc. has been widely used. There is. Above all, a resin composition prepared by blending a novolac type epoxy resin with a phenol resin as a curing agent and further adding an inorganic filler to the resin is currently the mainstream of resin encapsulation for semiconductor devices.

It is common to add a curing accelerator to the epoxy resin composition as a catalyst for accelerating the curing of the resin at the time of molding. For example, a nitrogen-containing or phosphorus-containing compound is used as the curing accelerator. There is.

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 the composition progresses, the moldability may be deteriorated, such as a decrease in fluidity during molding of the composition and an increase in viscosity. Therefore, the conventional epoxy resin composition varies in curability, resulting in electrical, mechanical, and
The chemical properties are likely to deteriorate and the storage stability is poor. Therefore,
It is necessary to strictly control the temperature during mixing and storage,
There is a drawback that the handling is troublesome, and it has been desired to solve these drawbacks.

The present invention has been made in view of the above circumstances, and provides a cured product having excellent storage stability, rapid curing during heat molding, and good electrical, mechanical, and chemical properties, a molding material, and a semiconductor. It is an object of the present invention to provide an epoxy resin composition which is useful for encapsulating a resin.

Means and Actions for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventor has found that an epoxy resin composition containing an epoxy resin, a phenolic curing agent, and an inorganic filler has the following general (I ) (However, in the formula, R ¹ is an aralkyl group having 7 to 20 carbon atoms,
R ² and R ³ are each a monovalent organic group having 1 to 7 carbon atoms,
n is an integer of 1 to 3. ) Is compounded as a curing accelerator, this curing accelerator is stable at room temperature and exhibits sufficient catalytic action only at the heating temperature during molding. Therefore, the epoxy resin and curing agent and other Curing does not progress during heating and mixing with the ingredients or during subsequent storage, and has excellent storage stability, and it quickly cures during heat molding to yield a cured product with good electrical, mechanical, and chemical properties. The inventors have found that an epoxy resin composition to be given can be obtained and have completed the present invention.

Therefore, the present invention provides (1) an epoxy resin, (2) a phenolic curing agent, (3) a curing accelerator represented by the above formula (I), and (4) an epoxy compounded with an inorganic filler as an essential component. A resin composition is provided.

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

The epoxy resin of the first essential component used in the epoxy resin composition of the present invention is not particularly limited as long as it has one or more epoxy groups in one molecule, and examples thereof include bisphenol type epoxy resin and alicyclic epoxy. A resin, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin or the like is preferably used, and it is particularly preferable to use a cresol novolac type epoxy resin.

Incidentally, the epoxy resin, from the viewpoint of moisture resistance of the composition, the content of hydrolyzable chlorine is 500ppm or less, free Na, Cl ions are each 2ppm or less, it is possible to use an organic acid content of 100ppm or less. desirable.

Further, in the present invention, as the epoxy resin, an alkenyl group-containing epoxy resin or an alkenyl group-containing phenol resin, more preferably the following formula (III) (However, in the formula, R ⁵ is Alternatively, it is a hydroxyl group, and p and q are integers represented by 0 ≦ p ≦ 10 and 1 ≦ q ≦ 3. R ⁶ is a hydrogen atom or a methyl group. ) An epoxy resin or phenol resin containing an alkenyl group represented by the following general formula (II) (However, in the formula, R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group, preferably a C 1-C 1 group such as a methyl group or an ethyl group.
8 alkyl groups, aryl groups having 6 to 10 carbon atoms such as phenyl groups, ClC ₃ H _6-, in which one or more hydrogen atoms of these groups are substituted with halogen atoms, Group _{etc., -C 2 H 4 Si (OCH} 3) a portion of the hydrogen atoms substituted with alkoxysilyl group _{3, -C 3 H 6 Si (} OCH 3) 3, -C 2 H 4 Si (OC
₂ H ₅ ) ₃ , And a and b are 0.01 ≦ a ≦ 1, preferably 0.03 ≦
a ≦ 0.5, 1 ≦ b ≦ 3, preferably 1.95 ≦ b ≦ 2.05, 1
It is a positive number that satisfies ≦ a + b <4, preferably 1.8 ≦ a + b ≦ 2.4. The number of silicon atoms in one molecule is 20-40.
It is an integer of 0, and the number of hydrogen atoms directly connected to a silicon atom in one molecule is 1 or more, preferably an integer of 1 to 5. It is preferable to add an addition polymer (silicone-modified epoxy resin or silicone-modified phenolic resin) with an organic silicon compound represented by The SiH group of the formula (II) is added to the alkenyl group of the epoxy resin or phenol resin of the formula (III) to form an addition polymer.

In this case, the above silicone-modified epoxy resin or phenol resin has a hydrolyzable chlorine content of 500 ppm.
In the following, free Na, Cl ions each 2ppm or less, preferably the organic acid content is 100ppm or less, when the content of hydrolyzable chlorine, free Na, Cl ions, organic acid exceeds the above value However, the heat resistance of the sealed semiconductor device may deteriorate.

The above silicone-modified epoxy resin or phenolic resin may be used alone or in admixture of two or more, and the compounding amount is 100 parts by weight of the total amount of the epoxy resin and the curing agent (parts by weight, It is preferably 5 to 70 parts, especially 8 to 50 parts. The amount of silicone-modified epoxy resin or phenol resin is 5
If it is less than 70 parts, it is difficult to obtain a sufficiently low stress property, and if it exceeds 70 parts, the mechanical strength of the molded product may decrease.

Next, as the second essential component, a phenol-based curing agent that is suitable for the epoxy resin is used, such as phenol novolac resin, cresol novolac resin, and bus phenol resin. The phenolic resin used as a curing agent contains 2 ppm or less of free Na and Cl ions and 1% or less of phenol in the monomer.
Organic acid such as formic acid generated by the Cannizzaro reaction of a trace amount of formaldehyde remaining during production is preferably 100 ppm or less, and when the content of free Na, Cl ions or organic acid is more than the above amount, the composition is sealed. The moisture resistance of the semiconductor device may deteriorate, and the amount of phenol in the monomer may be 1%.
If there is more, voids, unfilled,
Defects such as sink marks may occur. Further, the softening point of the phenolic resin is preferably from 50 to 120 ° C. When it is less than 50 ° C., the second-order transition temperature of the composition becomes low and the heat resistance may deteriorate, and when it exceeds 120 ° C. In some cases, the melt viscosity becomes too high, resulting in poor workability.

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, and 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.

In the present invention, the following general formula (I) is used as the third essential component. (However, in the formula, R ¹ is an aralkyl group having 7 to 20 carbon atoms,
R ² and R ³ are each a monovalent organic group having 1 to 7 carbon atoms,
n is an integer of 1 to 3. The compound shown by the above) is added as a curing accelerator.

Here, the substituent R ^{1 of the} formula (I) is an aralkyl group having a carbon number of 7 to 20, and examples thereof include a benzyl group, a 2-phenylethyl group, a 1-phenylethyl group and a 3-phenylpropyl group. Further, R ² and R ³ each have 1 to 7 carbon atoms.
Examples of the monovalent organic group include an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group, and a monovalent hydrocarbon group such as an aryl group such as a phenyl group and a tolyl group. , Phenyl groups are the most common. Further, n is an integer of 1 to 3, but generally n is 1 from the viewpoint of availability of raw materials.

Specifically as such a compound of the above formula (I),
Benzyltriphenylphosphonium ・ Tetrabutylborate, 1-phenylethyltriphenylphosphonium ・
Tetraphenyl borate, benzyl triphenyl phosphonium ethyl triphenyl borate, 2-phenyl ethyl triphenyl phosphonium tetraphenyl borate, benzyl triphenyl phosphonium tetraphenyl borate, benzyl tributyl phosphonium tetraphenyl borate, benzyl tributyl phosphonium
Tetraethyl borate, dibenzyl diphenylphosphonium tetrabutyl borate, tribenzyl phenylphosphonium tetrabutyl borate and the like are exemplified.

In addition, the compound of the above formula (I) is reacted with a corresponding aralkyl group-containing halide with a tertiary phosphine or the like, or after reacting an organic halide with a corresponding aralkyl group-containing tertiary phosphine. Known reactions (Chem.Ber.92,2756 (1956), J.Am.Che, such as reacting a boron compound (quaternary borate, alkali metal salt, etc.)
m.Soc.87,4156 (1965), etc.), for example, after reaction of benzyl bromide with triphenylphosphine or tributylphosphine, further reaction with sodium tetraphenylborate, etc. It can be synthesized, for example.

Further, in the present invention, the compound of the formula (I) may be used alone as a curing accelerator, but it may be used in combination with other curing accelerators, and as other curing accelerators, especially 1,8 −
The combined use with diazabicyclo-7-undecene is desirable from the viewpoint of the moisture resistance of the composition.

Further, the compounding amount of the compound of the formula (I) is preferably 0.1 to 10 parts, particularly 0.3 to 5 parts with respect to 100 parts of the epoxy resin as the first component, and if the compounding amount is less than 0.1 part, the curability is poor. On the other hand, if it exceeds 10 parts, the storage stability and moisture resistance may deteriorate. When 1,8-diazabicyclo-7-undecene is used in combination with other curing accelerator, it is 0.02 to 2 with respect to 1 part of the compound represented by the formula (I).
It is desirable to use them together in a mixing ratio of 1 part.

Next, as the inorganic filler of the fourth essential component, for example, 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 and the like are used.

The inorganic filler used in the present invention is amorphous,
Various materials such as sintered and spherical materials can be used, but as the sealing material, spherical or nearly spherical shape is particularly preferable. The average particle size is preferably 5 to 75 microns, but those having an average particle size of 0.1 to 5 microns may be used within a range not exceeding 30% of the total amount of the inorganic filler.

The amount of the inorganic filler contained in the composition is not particularly limited, but it is preferably 60% by weight or more of the entire composition.

Further, the inorganic filler may be pretreated with a silane coupling agent or the like. In this case, the silane coupling agent used for the treatment has a structural formula of the following formula (IV) Hydrolyzable residue-containing silanes represented by are preferably used.

Here, the substituent R ⁷ in the formula (IV) is a hydrogen atom,
Substituted or unsubstituted alkyl groups such as methyl group, ethyl group, propyl group, γ-mercaptopropyl group, γ-chloropropyl group, aryl groups such as phenyl group, epoxy,
Included below are those that are amino, acrylic, alkenyl, carboxyl functional.

_{H 2 NCH 2 CH 2 NHCH 2} CH 2 CH 2 - R 9 R 10 NCH 2 CH 2 CH 2 - R 9, R 10 = H or _{C d H 2d + 1 (d} = 1~6 integer) CH ₂ = ^{C (R 11) COO (CH} 2) n - R 11 = H or CH ₃ (n = 1~3 _{integer) CH 2 = CH (CH 2} ) m - (m = 0~4 integer) HOCO (CH ₂ ) _l- (l = an integer of 2 to 18) On the other hand, R ⁸ is, for example, a substituted or unsubstituted alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a methoxyethyl group, and an ethoxyethyl group, Vinyl group, allyl group, alkenyl group such as isopropenyl group, aryl group such as phenyl group, acetyl group, propionyl group, acyl group such as butynyl group and the like, among them, methyl group,
An ethyl group, an isopropenyl group and the like are common, and c is an integer of 1 to 4, but it is more preferable that c is 3 or 4.

The above-mentioned silane coupling agents may be used alone or in combination of two or more kinds, and further, those partially hydrolyzed in advance may be used.

The amount of silane coupling agent is 100% inorganic filler.
It is preferably in the range of 0.001 to 8 parts, more preferably 0.01 to 5 parts with respect to 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 may not be exhibited in some cases, and if the amount of the silane coupling agent is too large, the burr characteristics and the like may deteriorate rather.

As a treatment method with a silane coupling agent, either a dry method or a wet method may be used. The dry method is a ball mill, a Henschel mixer, etc., and the wet method is a method in which a silane coupling agent is mixed with an inorganic filler in a solvent and stirred. Can be done by doing. In this case, examples of the solvent 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. Alternatively, water and a tin-based, titanium-based, or amino compound as a hydrolysis accelerator may be used in combination. Note that it is also possible to sinter a heating furnace at about 400 to 1200 ° C. after the treatment as described above.

Various additives may 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, Carnauba wax is preferably used from the viewpoint of releasing property), pigments such as carbon black, cobalt blue and red iron oxide, flame retardants such as antimony oxide and halogen compounds, antiaging agents, silane coupling agents, ion exchange materials. It is also possible to appropriately mix the above.

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 and cools with a kneader, roll, extruder or the like which has been heated to 60 to 95 ° C. in advance. Then, it can be obtained by a method such as crushing.

Epoxy resin composition obtained in the present invention, IC, LSI,
It can be effectively used for resin encapsulation of semiconductors such as transistors, thyristors, and diodes, and manufacturing of printed circuit boards.

When the epoxy resin composition of the present invention is used to perform resin encapsulation of a semiconductor device, a molding method conventionally used,
That is, transfer molding, injection molding, casting method or the like can be used. Molding conditions are temperature
It is preferable to perform the post cure at 150 to 180 ° C. and 150 to 180 ° C. for about 2 to 16 hours.

EFFECT OF THE INVENTION The epoxy resin composition of the present invention is excellent in storage stability and rapidly cured during heat molding to give a cured product having good electrical, mechanical and chemical properties. It can be preferably used as a semiconductor sealing material.

<Examples and Comparative Examples> Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1] 600 parts by weight of spherical alumina (average particle size: 11 µm) (hereinafter simply referred to as "part") was put into a ball mill, and 0.05% by weight of 1,8
2.5 parts γ-containing diazabicyclo-7-undecene
Glycidoxytripropylmethoxysilane was sprayed and uniformly dispersed. Then, heat treatment was performed at 150 ° C. for 20 hours. This and the following formula The compound represented by 50 parts of a silicone-modified epoxy resin (subscript in the formula is an average value) which is an addition reaction product with a compound represented by: 13 parts of a cresol novolac type epoxy resin (epoxy equivalent 230),
Brominated epoxy resin (epoxy equivalent 280) 5 parts, phenol novolac resin (phenol equivalent 100) 32 parts, carnauba wax 1.5 parts, γ-glycidoxypropyltrimethoxysilane 1.5 parts, fused silica (average particle size 25 μm) 120
Part, carbon black 1.2 parts, benzyltriphenylphosphonium tetraphenylborate 1.22 parts, 1,8
0.14 parts of diazabicyclo-7-undecene was placed on a hot roll at 70 to 80 ° C, kneaded, and cooled and ground to obtain an epoxy resin composition.

[Example 2] An epoxy resin composition was prepared under the same conditions except that the benzyltriphenylphosphonium / tetraphenylborate (1.22 parts) in Example 1 was replaced with benzyltributylphosphonium / tetraphenylborate (1.08 parts). Got

Example 3 An epoxy resin composition was prepared under the same conditions except that 1.22 parts of benzyltriphenylphosphonium / tetraphenylborate in Example 1 was replaced with 1.16 parts of dibenzyldiphenylphosphonium / tetrabutylborate. I got a thing.

[Example 4] Benzyltriphenylphosphonium tetraphenylborate 1.22 parts and 1,8-diazabicyclo-7-undecene 0.14 parts in Example 1 were replaced with 2.11 parts of benzyltriphenylphosphonium tetraphenylborate alone, and the same composition was used. An epoxy resin composition was obtained.

Example 5 An epoxy resin composition was obtained in the same composition by replacing the inorganic filler in Example 1 with 450 parts of crystalline silica (average particle size 18 μm) only.

[Example 6] The epoxy resin composition was obtained in the same manner by replacing the inorganic filler in Example 1 with 400 parts only of fused silica (average particle size 20 µm).

[Comparative Example 1] An epoxy resin composition was obtained with the same composition, except that 1.29 parts of the compound benzyltriphenylphosphonium tetraphenylborate in Example 1 was replaced with 0.52 parts of 2-phenylimidazole.

[Comparative Example 2] An epoxy resin composition was obtained in the same manner, except that 1.29 parts of the compound benzyltriphenylphosphonium tetraphenylborate in Example 1 was replaced with 0.55 parts of triphenylphosphine.

[Comparative Example 3] An epoxy resin composition was obtained in the same composition by replacing 1.29 parts of the compound benzyltriphenylphosphonium / tetraphenylborate in Example 1 with 1.27 parts of tetraphenylphosphonium / tetraphenylborate.

[Comparative Example 4] An epoxy resin composition was obtained in the same formulation, except that 1.29 parts of the compound benzyltriphenylphosphonium tetraphenylborate in Example 6 was replaced with 0.48 part of 2-phenylimidazole.

For these epoxy resin compositions, gel time,
Storage stability and humidity resistance of power IC (aluminum corrosion test)
Was evaluated by the following method. The results are shown in Table 1.

Gelation time The gelation time at 175 ° C was measured.

Hardness ² at 175 ℃ / 70kgcm- ² using transfer molding machine
The mature hardness after minute molding was measured using a Barcol hardness meter 935.

Aluminum wiring corrosion rate A 14-pin IC designed to study the corrosion of aluminum metal electrodes was molded with an epoxy resin composition by the transfer molding method, and a bias voltage of 10 V was applied in a high-pressure pot at 130 ° C and 85% humidity. After 100 hours, the open defect rate of the wiring was examined.

From the results shown in Table 1, the epoxy resin compositions of the present invention (Examples 1 to 6) were the epoxy resin compositions (Comparative Example 1) in which compounds other than the compound of the above formula (I) were blended as a curing accelerator.
It was confirmed that a cured product having excellent storage stability and excellent electrical, mechanical, and chemical properties was obtained as compared with (4) to (4).

─────────────────────────────────────────────────── ─── 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, Isobe, Annaka-shi, Gunma No. 1 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) Reference JP-A-63-245949 (JP, A) JP-A-63-22822 (JP, A) JP-A-48-800 ( JP, A) JP-A-2-14214 (JP, A) JP-A-2-3411 (JP, A) JP-A-2-3412 (JP, A)

Claims (2)

[Claims] 1. A (1) epoxy resin, (2) a phenolic curing agent, (3) a curing accelerator represented by the following general formula (I), (However, in the formula, R ¹ is an aralkyl group having 7 to 20 carbon atoms,
R ² and R ³ are each a monovalent organic group having 1 to 7 carbon atoms,
n is an integer of 1 to 3. (4) An epoxy resin composition comprising an inorganic filler as an essential component. 2. An alkenyl group of an alkenyl group-containing epoxy resin or an alkenyl group-containing phenol resin is represented by the following formula (I
I) (Wherein R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group, and a and b are 0.01 ≦ a ≦ 1,1 ≦ b ≦ 3,1 ≦ a + b <4
Is a positive number that satisfies. The number of silicon atoms in one molecule is an integer of 20 to 400, and the number of hydrogen atoms directly connected to the silicon atom in one molecule is an integer of 1 or more. The epoxy resin composition according to claim 1, wherein a silicone-modified epoxy resin or a silicone-modified phenol resin, which is a polymer obtained by adding the SiH group of the organic silicon compound represented by the formula (3), is blended.