JPH03157447A - Epoxy resin composition and cured product of epoxy resin - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition suitable as sealing materials, etc., for semiconductors by blending alumina and/or aluminum nitride as an inorganic filler with tetraphenylphosphonium tetraphenylborate as a curing accelerator. CONSTITUTION:An epoxy resin composition obtained by blending (A) an epoxy rein, preferably an epoxy resin containing 5-70wt.% silicone-modified epoxy resin prepared by adding SiH groups of an organosilicon compound expressed by the formula (R<1> is monofunctional hydrocarbon group, OH, etc.; a is 0.01-1; b is 1-3; a+b is integer of 1-4; the number of Si in one molecule is 1-400; the number of H directly bound to Si is >=1) to alkenyl groups of an alkenyl group- containing epoxy resin with (B) a curing agent (preferably phenol novolak resin), (C) alumina and/or aluminum nitride as an inorganic filler and (D) tetraphenylphosphonium tetraphenylborate as a curing accelerator.

Description

[Detailed Description of the Invention] The present invention relates to an epoxy resin composition suitable for use as a molding material, a semiconductor encapsulating material, etc., and a cured product thereof, which is easy to spread. Conventionally, inorganic fillers such as fused silica and crystalline silica have been mainly used as fillers in epoxy resin compositions for semiconductor encapsulation. Crystalline silica with good quality is used.

However, even if crystalline silica is used as a filler and its content is increased, the thermal conductivity remains at 65 cal/c.
The limit is to increase the thermal conductivity to about m・℃・sec, and if the content of crystalline siliency is increased to obtain higher thermal conductivity, the fluidity of the composition will become too poor and transfer molding will no longer be possible. There were drawbacks such as.

Therefore, in recent years, attempts have been made to solve the above problem by using alumina or aluminum nitride, which has a higher thermal conductivity than crystalline silica and a lower coefficient of thermal expansion, as a filler. However, according to the inventors' study,
Although thermal conductivity increases when alumina or aluminum nitride is used, the effect of the curing accelerator in the epoxy resin composition is inhibited due to their surface activity or impurities present in the 1# amount. There were problems in that initial and post-storage moldability deteriorated, and the moisture resistance of the cured product was inferior compared to conventional silica compound systems.

That is, alumina and aluminum nitride have high thermal conductivity and low coefficient of thermal expansion, so they are ideal as fillers for future semiconductor encapsulation materials.On the other hand, 2-phenylimidazole and 1 are suitable as curing accelerators for epoxy resins. It has been common to use amine compounds such as 8-diazabicyclo-7-undecene and phosphorus compounds such as triphenylphosphine alone or in combination, but in epoxy resin compositions that use alumina or aluminum nitride as inorganic fillers. When imidazole is used as a curing accelerator, the purity of the composition is poor and the moisture resistance reliability of the cured product is poor;
``Riphenylphosphine and 1,8-diazabicyclo-7
- When undecene was used, the initial curability decreased during storage.

The present invention was made to solve the above-mentioned problems of epoxy resin compositions using alumina or aluminum nitride as fillers, and has a low coefficient of thermal expansion and excellent heat dissipation.
At the same time, it is an object of the present invention to provide an epoxy resin composition that gives a cured product with good moisture resistance reliability, good moldability, and is useful for semiconductor encapsulation, etc., and a cured product thereof.

In order to achieve the above object, the inventor of the present invention has conducted extensive studies on curing accelerators to be added to epoxy resin compositions using alumina and/or aluminum nitride as inorganic fillers, and has found that curing accelerators can be added to epoxy resin compositions that use alumina and/or aluminum nitride as inorganic fillers. When tetraphenylphosphonium tetraphenylborate is used as an agent, the above-mentioned triphenylphosphine and 1,8-diazabicyclo-
It has been found that the disadvantages of using 7-undecene can be overcome. Furthermore, as an epoxy resin, the alkenyl group of the alkenyl group-containing epoxy resin has the following formula (1) % formula % (1) (wherein R1 is a substituted or unsubstituted monovalent hydrocarbon, a hydroxyl group, an alkoxy group, or an alkenyl group). Indicates an oxy group, a and b are 0.01≦a≦1゜1≦b≦3.1≦a
It is a positive number satisfying +b≦4. Further, the number of silicon atoms in one molecule is an integer of 1 to 400, and the number of hydrogen atoms directly bonded to silicon atoms in one molecule is an integer of 1 or more.

) It is effective to blend a silicone-modified epoxy resin formed by adding an E S i H group of an organosilicon compound represented by using borate as a curing accelerator;
More preferably, by blending the above-mentioned silicone-modified epoxy resin, a cured product having a small coefficient of thermal expansion, excellent heat dissipation properties, and good moisture resistance reliability can be obtained, and moldability is also good, and it can be used as a molding material, semiconductor The present inventors have discovered that an epoxy resin composition suitable for sealing materials, etc. can be obtained, and the present invention has been completed.

Therefore, the present invention provides an epoxy resin composition containing alumina and/or aluminum nitride as an inorganic filler and tetraphenylphosphonium tetraphenylborate as a curing accelerator, and a cured product thereof.

The present invention will be explained in more detail below.

The epoxy resin composition of the present invention is composed of an epoxy resin, a curing agent, an inorganic filler, a curing accelerator, and, if necessary, a release agent, a pigment, a silane coupling agent, and the like.

In this case, the epoxy resin used in the composition of the present invention is not particularly limited as long as it has one or more epoxy groups in one molecule, such as bisphenol A type epoxy resin,
Alicyclic epoxy resins, cresol novolac type epoxy stool fat, etc. are preferably used, and it is particularly desirable to use cresol novolac type epoxy resins.

Note that the above epoxy resin has a hydrolyzable chlorine content of 500 ρρm or less and a free Na content from the viewpoint of moisture resistance of one composition.
, CQ ions are less than 2 ppm each, organic acid content is 1
It is desirable to use one with a content of 100 pp or less.

The composition of the present invention also includes an alkenyl group-containing epoxy resin, especially the following formula 1 (%) is a hydroxyl group, and p and q are integers represented by 0≦p≦10, 1≦q≦3. It is. ) and an alkenyl group-containing epoxy resin represented by the following formula (
1) % formula %) (However, in the formula, R1 represents a substituted or unsubstituted monovalent hydrocarbon group, hydroxyl group, alkoxy group, or alkenyloxy group, and a and b are 0.01≦a≦1゜1≦b ≦3.1≦a
It is a positive number satisfying +b≦4. Further, the number of silicon atoms in one molecule is an integer of 1 to 400, and the number of hydrogen atoms directly bonded to silicon atoms in one molecule is an integer of 1 or more. ) It is preferable to blend a silicone-modified epoxy resin which is an addition polymer with an organosilicon compound represented by: In addition, this organosilicon compound has its =S i
The H group is added to the alkenyl group of the epoxy resin to form an addition polymer.

Here, R1 in formula (1) is a substituted or unsubstituted monovalent hydrocarbon group, hydroxyl group, alkoxy group or alkenyloxy group, preferably an alkyl group having 1 to 8 carbon atoms such as a methyl group or an ethyl group. 6-10 carbon atoms such as groups, phenyl groups, etc.
an aryl group, a group such as CQC3)I-1ca÷ in which one or more hydrogen atoms of these groups are substituted with a halogen atom, an alkoxy group having 1 to 5 carbon atoms such as a hydroxyl group, a methoxy group, an ethoxy group, and a , b is 0.01≦a≦1, preferably 0.03≦a≦1.1≦b≦3, preferably 1.95≦
b≦2.05.1≦a+b≦4, preferably 1.8≦a
It is a positive number satisfying 10b≦4.

In this case, the silicone-modified epoxy resin has a hydrolyzable chlorine content of 500 ppm or less and free N.
A, CQ ion is preferably 2 ρρm or less, and 2 is preferably hydrolyzable chlorine and free Na.

When the content of CQ ions and organic acids exceeds the above values.

The heat resistance of the sealed semiconductor device may deteriorate.

The above silicone-modified epoxy resin may be used alone or in combination.
A mixture of two or more species may be used, and the amount thereof is preferably 5 parts or more, particularly 5 to 70 parts, based on 100 parts (parts by weight, hereinafter the same) of the epoxy resin blended into the composition. . If the amount of silicone-modified epoxy resin is less than 5 parts, it is difficult to obtain sufficient low stress properties, and if it exceeds 70 parts, the mechanical strength of the molded product may decrease.

In addition, the hardening agent used is appropriate for the epoxy resin.
For example, acid anhydrides such as trimellitic anhydride and tetrahydrophthalic anhydride, phenol novolak resins, and the like are used, and among them, it is optimal to use phenol novolac resins. The phenol novolak resin used as a curing agent contains 2 ppm or less of free Na and CQ ions each, and 1% or less of monomer phenol, which is produced by the Cannizaro reaction of a trace amount of formaldehyde remaining during manufacturing. Organic acids such as formic acid are 110
It is preferably 0 pp or less, and if the content of free Na, CQ ions or organic acids is higher than the above value, when the composition is used as a semiconductor encapsulant, the moisture resistance of the encapsulated semiconductor device will deteriorate. If the amount of phenol in the monomer is more than 1%, defects such as voids, unfilling, sink marks, etc. may occur in molded articles made from the composition. Furthermore, the softening point of the phenol novolak resin is preferably 50 to 120°C; if it is less than 50°C, the glass transition point of the composition may become low and the heat resistance may deteriorate; if it exceeds 120°C, the composition may deteriorate. Melt viscosity may become high and workability may be poor.

Here, the blending amount of the curing agent is not particularly limited.

It is preferable that the molar ratio between the epoxy group of the epoxy resin and the phenolic hydroxyl group or acid anhydride group of the curing agent is in the range of 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 secondary transition temperature (T' g ) of the molded product may deteriorate, leading to a decrease in heat resistance. Secondary transition temperature and electrical characteristics may deteriorate.

The epoxy resin composition of the present invention includes the above epoxy resin,
Together with the curing agent, tetraphenylphosphonium tetraphenylborate is blended as a curing accelerator, and alumina and/or aluminum nitride is blended as an inorganic filler.

In this case, the amount of tetraphenylphosphonium tetraphenylborate as a curing accelerator is preferably 0.1 to 10 parts, particularly 0.3 to 5 parts, based on 100 parts of the epoxy resin, and the amount is less than 0.1 part. If it is not used, the curability may deteriorate, while if it exceeds 10 parts, the storage stability and moisture resistance properties may be deteriorated.

In addition, as a curing accelerator, other curing accelerators may be used in combination with tetraphenylphosphonium tetraphenylborate. In particular, from the viewpoint of moisture resistance, 1,8-diazabicyclo-7-undecene, for example, tetraphenyl It is desirable to use them together in a blending ratio of 0.02 to 2 parts per 1 part of phosphonium te to 1 part of raphenylborate.

Next, the alumina and aluminum nitride used as the inorganic filler in the present invention can be in various shapes such as amorphous, sintered, and spherical, but the composition can be used as the sealing material. In this case, a spherical one is particularly suitable.

Further, the average particle size of alumina and aluminum nitride is preferably 1 to 100 microns, more preferably 5 to 75 microns, but the average particle size is 0.5 to 100. A material having a diameter of 1 to 1 micron may also be used.

Furthermore, it is preferable that alumina and aluminum nitride be treated in advance with a silane coupling agent, etc. The silane coupling agent used in the treatment of alumina and aluminum nitride has a structural formula represented by RniecSi(OR')c. Silanes containing hydrolyzable residues are preferably used.

In this case, R3 is a hydrogen atom, a non-functional alkyl group such as a methyl group, an ethyl group, a propyl group, a vinyl group, an isopropenyl group, a phenyl group, an alkenyl group, an aryl group,
Mention may be made of the following groups which are epoxy, amino, acrylic, alkenyl, carboxyl functional.

Cl-1zCHCH,QC:H,CH,CH,-\/H,NCH,CH2NHCH2C82CH,-HR'N
CH, CHiCHz-R'=H, CdHid Yu1. d=
Integer from 1 to 4 CHz=C(R')Coo(CH2)n
R'=H1CH-n=1.3CH,=CH(CH2
) m-m=integer from 1 to 4 HOCO(CHz')Q-Ω=
An integer from 2 to 18. R4 is an alkyl group or an alkenyl group.

Examples include aryl groups and carbonyl groups, among which methyl groups, ethyl groups, isopropenyl groups, etc. are common, and isopropenyl groups are particularly preferred.
A number of ˜4 is preferred, especially 3 or 4.

Note that the silane coupling agent may be used alone, or two or more types may be used in combination, or the above-mentioned silane coupling agent may be partially hydrolyzed in advance.

Either a dry or wet method can be used to treat alumina and aluminum nitride with a silane coupling agent. The dry method uses a Henschel mixer, etc., and the wet method involves treating alumina and aluminum nitride with a silane coupling agent in a solvent. This can be done by mixing and stirring.

In this case, the amount of silane coupling agent used is 0.001 to 100 parts of alumina and aluminum nitride.
8 parts, particularly preferably in the range of 0.01 to 5 parts. If the amount of the silane coupling agent used is less than 0.001 part, the treatment effect may not be sufficiently obtained, and if it is more than 8 parts, the high thermal conductivity, which is a characteristic of alumina and aluminum nitride, will be achieved.

Low thermal expansion properties may be lost.

Examples of solvents include hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol, and isopropyl alcohol, ketones such as acetone and 2-butanone, and ethers such as isopropyl ether and tetrahydrofuran. Water and a tin-based, titanium-based, or amine compound as a hydrolysis accelerator can also be used in combination.

Furthermore, after being treated with a silane coupling agent in this way, it can be sintered in a heating furnace at about 400 to 1200°C.

Furthermore, regarding the aluminum nitride laminated membrane 3, it is more preferable to treat a part of it by oxidation or the like so that an alumina film is formed by oxidizing its surface.

It is desirable to perform the above-mentioned silane treatment thereon.

In the present invention, in addition to alumina and aluminum nitride, other inorganic fillers such as fused silica and crystalline silica can be used as the inorganic filler, and the amounts of alumina and aluminum nitride are not particularly limited. To make effective use of its characteristics of high heat dissipation and low coefficient of thermal expansion.

The total amount of inorganic fillers is 50% by weight or more, especially 70 to 90% by weight of the entire composition, and the blending ratio of alumina and aluminum nitride in the total inorganic fillers is 50% by weight or more, especially 70 to 95% by weight. Preferably, it is % by weight.

Various additives can be further added to the composition of the present invention, if necessary. Carnauba wax is preferably used from the viewpoint of moldability), pigments such as carbon black, cobalt blue, red iron, flame retardants such as antimony oxide and halogen compounds, anti-aging agents, silane coupling agents,
One or more types of ion exchange substances and other additives can be blended.

In addition, when producing the epoxy resin composition of the present invention, predetermined amounts of the above-mentioned components are uniformly stirred and mixed,
It can be obtained by heating to 0 to 95°C, kneading with a kneader, roll, extruder, etc., cooling, and pulverizing. Here, there is no particular restriction on the order of blending the components.

As mentioned above, the epoxy resin composition of the present invention includes IC,
It can be effectively used for manufacturing printed circuit boards and sealing resins for semiconductor devices such as LSIs, transistors, thyristors, and diodes.

Here, when sealing the semiconductor device, conventionally employed molding methods such as transfer molding, injection molding, and casting can be used. In this case, the molding temperature of the epoxy resin composition is 150
~180℃, post cure at 150℃~180℃ 2
It is preferable to carry out the treatment for 16 hours.

The epoxy resin composition of the present invention has a small coefficient of thermal expansion, excellent heat dissipation properties, and good moisture resistance reliability, and
It provides a cured product with good moldability and is useful as a molding material and a semiconductor encapsulating material.

<Examples, Comparative Examples> The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, in the following examples, all parts are parts by weight.

[Example 1] The following components were kneaded using heated rolls at 80 to 90°C, cooled and ground to obtain an epoxy resin composition.

(Epoxy equivalent j1230) Brominated epoxy resin (Epoxy equivalent 28o) Phenol novolac resin (Phenol equivalent 100) 2 Add carnauba wax tramethoxysilane (TMS), add 0.5 part of pure water and heat, and reflux toluene. After continuing to stir for 5 hours, the solvent was distilled off at 150'C under reduced pressure, and the surface was treated.

In addition, the silicone-modified epoxy resin (■) is carbon black filler, spherical alumina (average particle size 25 pnI), fused silica hardening accelerator, 00 00 silicone-modified epoxy resin 1, 50.
A silicone-modified epoxy resin (the subscript in the formula is an average value) which is an addition reaction product with 1.0 part of Te was used.

[Example 2] Methyltriisopropenoxysilane (MTTPS) was used instead of 1.0 part of tetramethoxysilane as the spherical alumina.
)4-. An epoxy resin composition was obtained by carrying out the treatment under the same formulation and conditions as in Example 1, except that the surface treatment was carried out using 0 parts.

[Example 3] An epoxy resin composition was obtained in the same manner as in Example 1, except that 600 parts of spherical alumina treated in the same manner as in Example 1 was used without blending fused silica as a filler.

[Example 4] An epoxy resin composition was obtained in the same manner as in Example 1, except that an addition reaction product (silicone-modified epoxy resin (■)) was used instead of silicone-modified epoxy resin I in Example 1.

[Example 5] 1.27 parts of tetraphenylphosphonium tetraphenylborate in Example 1 as a curing accelerator, 1,8-
0.14 parts of diazabicyclo-7-undecene and 1.8 parts of tetraphenylphosphonium tetraphenylborate
An epoxy resin composition was obtained using the same formulation as in Example 1 except that the amount was changed to 2 parts.

[Example 6] An epoxy resin composition was obtained in the same manner as in Example 1 except that untreated alumina was used instead of surface-treated spherical alumina.

[Example 7] Epoxy was used in the same formulation as in Example 1, except that 350 parts of aluminum nitride (average particle size 17-) treated in the same manner as in Example 2 was used instead of the surface-treated spherical alumina. A resin composition was obtained.

[Example 8] An epoxy resin composition was obtained in the same manner as in Example 7, except that 450 parts of aluminum nitride treated in the same manner as in Example 7 was used without blending fused silica as a filler.

[Comparative Example 1] An epoxy resin composition was obtained with the same formulation as in Example 1, except that 1-1.27 parts of tetraphenylphosphonium tetraphenylbore in Example 1 was changed to 0.155 parts of triphenylphosphine (TPP). .

[Comparative Example 2] 1.27 parts of tetraphenylphosphonium tetraphenylbore h in Example 1, 1.8-diazabicyclo-
An epoxy resin composition was obtained in the same manner as in Example 1, except that 0.14 parts of 7-undecene was replaced with 1.68 parts of 2-phenylimidazole (2-PIZ).

[Comparative Example 3] 1.27 parts of the tetraphenylphosphonium tetraphenylbore h in Example 6 was added to 0 part of triphenylphosphine.
．． An epoxy resin composition was obtained using the same formulation as in Example 6 except that the amount was changed to 55 parts.

[Comparative Example 4] An epoxy resin composition was obtained in the same manner as in Example 7 except that 1.2'7 parts of tetraphenylphosphonium tetraphenylborate in Example 7 was changed to 0.55 parts of triphenylphosphine.

[Comparative Example 5] An epoxy resin composition was obtained using the same formulation as in Example 1, except that 500 parts by weight of surface-treated spherical alumina in Example 1 was replaced with 500 parts by weight of crystalline silica (average particle size 28 μ5).

Regarding these epoxy resin compositions, curability during molding, storage stability, bending strength, thermal shock resistance test, and power IC
The moisture resistance (aluminum corrosion test) was evaluated as 3f using the following method. The results are shown in Tables 1 and 2.

Spiral flow value: 175°C, 70°C using a mold that complies with EMMI standards.
It was measured under the condition of kg/d.

Hard-Koichi It was measured using Barcol hardness meter 935.

According to JIS-6911, 175°C 170kg/
(d, 10 rm x 4 nu under conditions of 2 minutes of molding time
Measurements were made on molded X100M shafts and post-cured at 180° C. for 4 hours.

Using a test piece measuring 4 rrrn x 4 trrn x 15 m, the temperature was measured using a deiradometer at a rate of 5° C. per minute.

A disk having a size of 5011111φX9nwn was measured by the unsteady hot wire method using a Shotherm QTM-D quick thermal conductivity meter manufactured by Showa Denko.

A silicon chip with a size of 9 nm x 4.5 nm x 0.5 on was glued to a 14PIN-IC frame (4270), and an epoxy resin composition was applied to it under molding conditions of 175°C.
After molding for 2 minutes and post-curing at 180°C for 4 hours, thermal cycles of 0°C x 5 minutes to 180' CXS were repeated in the liquid phase, and the resin crack occurrence rate after 1000 cycles was measured.

An epoxy resin composition was molded into a 14-pin IC designed to examine the corrosion of aluminum metal electrodes using the transfer molding method, and the product was placed in a high-pressure cooker at 121°C and 100% humidity for 1500 hours to reduce the open failure rate of wiring. Examined.

[Example 9] The composition obtained in Example 1 was made into a 20% solution in toluene to obtain a liquid composition. Molded products obtained by casting and curing this composition exhibited good physical properties similar to those of the cured products of Examples 1 to 8.

From these results, the epoxy resin composition of the present invention containing alumina and/or aluminum nitride as an inorganic filler and tetraphenylphosphonium tetraphenylborate as a curing accelerator has a coefficient of thermal expansion of the cured product. It was confirmed that it is small, has excellent moisture resistance reliability, and has good moldability.

Claims (1)

[Scope of Claims] 1. An epoxy resin composition comprising alumina and/or aluminum nitride as an inorganic filler and tetraphenylphosphonium tetraphenylborate as a curing accelerator. 2. The alkenyl group of the alkenyl group-containing epoxy resin has the following formula (1) ▲ Numerical formula, chemical formula, table, etc. ▼... (1) (However, in the formula, R^1 is a substituted or unsubstituted monovalent hydrocarbon group, hydroxyl group, alkoxy group or alkenyloxy group, a and b are 0.01≦a≦1, 1≦b≦3, 1≦
A positive number that satisfies a+b≦4, and the number of silicon atoms in one molecule is an integer of 1 to 400, and the number of hydrogen atoms directly bonded to silicon atoms in one molecule is an integer of 1 or more. It is. 2. The epoxy resin composition according to claim 1, further comprising a silicone-modified epoxy resin added with a ≡SiH group of an organosilicon compound represented by the following formula. 3. A cured epoxy resin obtained by curing the composition according to claim 1 or 2.