JPH02129220A - Epoxy resin molding material for sealing electronic component and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain the title molding material with excellent thermal shock resistance, humidity resistance, and molding processability by mixing each specified epoxy resin, phenolic compd., silicone polymer, silane coupling agent, and inorg. filler as essential components. CONSTITUTION:An epoxy resin with 2 or more epoxy groups in the molecule (e.g., cresol novolak type epoxy resin), a compd. with 2 or more phenolic OH groups in the molecule (e.g., phenol novolak resin), a silicone polymer with an average MW of 5,000-50,000 having a polyalkylene ether group pref. with an MW of 400-4,000 and with a structure of formula I (wherein a/b<=0.5), a silane coupling agent with a ureide group [e.g., a compd. of formula II (wherein R is a lower alkylene; X is a hydrolyzable group such as methoxy)] and an inorg. filler with the max. particle diameter of 200mum (e.g., a molten silica powder) are mixed together as essential components.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an epoxy resin molding material for encapsulating electronic components.
For more information, see Jonetsu? The present invention relates to an epoxy resin molding material for encapsulating electronic components that has excellent impact resistance, heat resistance, moisture resistance, and molding workability.

[Prior Art] Conventionally, epoxy resin molding materials have been widely used for encapsulating electronic components such as coils, capacitors, transistors, and ICs. The reason for this is that epoxy resin has electrical properties, heat resistance, and mechanical properties.

This is because various properties such as adhesion with the insert are well balanced.

However, there is a tendency for electronic component packages to become smaller and thinner, resulting in the problem of packages cracking during temperature cycling. On the other hand, in the field of epoxy resin molding materials for IC sealing, thermal shock resistance is generally improved using silicone compounds.

[Problems to be Solved by the Invention] Modification of epoxy resin molding materials using silicone compounds is effective in terms of thermal shock resistance.

In many cases, moldability is impaired. That is, the silicone compound oozes out during melt molding, causing stains on the mold and the appearance of the molded product. This is generally due to the large difference in compatibility between silicone compounds and epoxy resins. Therefore, it is important to enhance the interaction between the silicone compound and the epoxy resin to prevent separation and seepage during melt molding.

The present invention has been made to solve these drawbacks, and aims to provide an epoxy resin molding material for encapsulating electronic components that has good thermal shock resistance, heat resistance, and excellent moldability. be.

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the inventors have found that the above objects can be achieved by blending specific compounds into an epoxy resin system. They discovered this and completed the present invention.

Namely, the epoxy resin molding material for encapsulating electronic components of the present invention is (A) an epoxy resin having two or more epoxy groups in one molecule, and (B) a compound having two or more phenolic hydroxyl groups in one molecule. , (C) a silicone polymer having a polyalkylene ether group, (D) a silane coupling agent having a ureido group (H2NGONH-).

(E) It is characterized by containing an inorganic filler having a maximum particle size of 200 μm or less as an essential component.

In one molecule of component (A) used in the present invention, 2
There are no restrictions on the epoxy resin having 2 or more epoxy groups, as long as it is commonly used in epoxy resin molding materials for encapsulating electronic components, including phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, etc. Epoxidized novolak resin of phenols and aldehydes, bisphenol A,
Diglycidyl ethers such as bisphenol B, bisphenol F and bisphenol S, glycidyl ester type epoxy resins obtained by the reaction of polybasic acids such as phthalic acid and dimer acid with epichlorohydrin, and polyamines such as diaminodiphenylmethane and isocyanuric acid and epichlorohydrin. There are glycidylamine type epoxy resins obtained by reaction, linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid, and alicyclic epoxy resins, and any number of these can be used in combination as appropriate. be able to.

Compounds having two or more phenolic hydroxyl groups in one molecule of component (B) used in the present invention include phenols such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, and bisphenol F, and formaldehyde. There are novolac-type phenolic resins that can be thickened by condensation reaction under acidic catalysts, bisphenol A, bisphenol F, polyparavinylphenol resins, and polyhydric phenols such as resorcinol, catechol, and hydroquinone, which can be used alone or in combination of two or more. The equivalent ratio of (A) to the epoxy resin (number of hydroxyl groups in (B)/number of epoxy groups in (A)) is not particularly limited, but is preferably 0.7 to 1.3.

Component (C) used in the present invention is a silicone polymer having a structure represented by the general formula. Here R
1 is generally a polyalkylene ether group consisting of repeating units R-0, and R is a methylene group or a polymethylene group and its derivatives. R2 is an epoxy group such as or a carboxyl group such as -R3-COOR. Here, R3 and R4 are +CF1. It is a lower alkylene group such as .

For thermal shock resistance and moldability (bleeding during molding), which are the main objectives of the present invention, polyalkylene ether groups in particular play an important role. The structure represented by (a/b is an integer having the relationship of 0.5) is preferable, and the molecular weight is 40
0 to 4000 is suitable. The reason for this is that a/b is 0
．． This is because if it is 5 or more, the moisture resistance may decrease due to the hydrophilic nature of the ethylene oxide component. From this point of view, a
It is more desirable that /b is 0 or 0.2 or less, and if the molecular weight is 400 or less, it will have little effect on thermal shock resistance and moisture resistance.

If the molecular weight is 4,000 or more, fluidity during molding may be impaired. Furthermore, the ratio of the polyalkylene ether group of R1 is preferably 10 to 60% by weight based on the silicone polymer of component (C).

There is no particular limitation, and the reason for this is that if it is less than 10% by weight, it will have poor compatibility with the base resin and problems such as seepage will occur during molding, and if it exceeds 60% by weight, the polyalkylene ether group will become hydrophilic. This is because moisture resistance tends to decrease. Furthermore, the ratio of the epoxy group or carboxyl group in R2 is not particularly limited, but (C)
1000 to 1000 as the functional group equivalent of the component silicone polymer
A range of 10,000 is preferred, more preferably 15
The range is from 00 to 4000. The reason for this is that when the functional group equivalent is less than 1,000 or more than 10,000, there is little effect on thermal shock resistance. The molecular weight of the silicone polymer as component (C) is not particularly limited;
~5oooo is preferable, because if it is less than 5000, there is little effect on thermal shock resistance, and if it is more than 5000, the viscosity of the molding material increases and fluidity during molding decreases.

Furthermore, in order to appropriately produce the effects of the present invention, a silicone compound (C) having an epoxy group and a silicone compound (B) having an epoxy group.
The component phenolic resin can be heated and mixed in advance in the presence of a curing accelerator that promotes the reaction between the epoxy group and the phenolic hydroxyl group. Examples of the curing accelerator include 1°8-diaza-bicyclo(5,4,O)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol. Tertiary amines, imidasols such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-hebdadecylimidazole, tributylphosphine, methyldiphenylphosphine, triphenyl phosphine, diphenylphosphine,
Organic phosphines such as phenylphosphine, tetraphenyl such as tetraphenylphosphonium-tetraphenylborate, triphenylphosphine-tetraphenylborate, 2-ethyl-4-methylimidazole-tetraphenylborate, N-methylmorpholine-tetraphenylborate, etc. There are boron salts, etc., and one type or two or more types can be used as appropriate. The conditions for heating and mixing the components (B) and (C) are not particularly limited.

120°C to 180°C without solvent or using a suitable solvent
, a range of 1 hour to 10 hours is preferred. Under these conditions, the phenolic hydroxyl group of component (B) and the epoxy group of component (C) can react effectively, which is particularly effective for improving thermal shock resistance and preventing seepage during molding. In this case, the epoxy equivalent of component (C) is important, and in order to effectively exhibit the effect, the epoxy equivalent [150
A range of 0 to 4000 is preferred.

Furthermore, in order to appropriately produce the effects of the present invention, a silicone compound (C) having a carboxyl group and (
The epoxy resin of component A) can be heated and mixed in advance in the presence of a curing accelerator that promotes the reaction between epoxy groups and carboxyl groups. As this curing accelerator,
One or more types of curing accelerators similar to the aforementioned curing accelerators that promote the reaction between epoxy groups and phenolic hydroxyl groups can be used as appropriate. The conditions for heating and mixing component (A) and component (C) are not particularly limited, but may be in the range of 120°C to 180°C for 1 to 10 hours without a solvent or using an appropriate solvent. preferable.

Under these conditions, the epoxy group of component (A) and the carboxyl group of component (C) can react effectively, which is particularly effective for heat impact resistance and prevention of seepage during molding. In this case, the carboxyl equivalent of component (C) is important, and in order to effectively exhibit the effect, the carboxyl equivalent is preferably in the range of 1,500 to 4,000 as described above.

The ureido group-containing silane coupling agent (D) used in the present invention is a silane monomer represented by the general formula %. Here, R is +CH
It is a lower alkylene group such as 2-%, and X is a hydrolyzable group such as a me-1-oxy group or an ethoxy group. In the present invention, by using component (D), an epoxy resin molding material for electronic component sealing and a lead frame (Cu-based, Fe
etc.), it is possible to maintain a good level of adhesion with the aluminum wiring and passivation (inorganic protective film) on the RC element. That is, in the present invention, even when component (D) is not used, good performance is shown in terms of thermal shock resistance and moldability, but due to the influence of the silicone compound of component (C), the epoxy resin molding material for encapsulating electronic components is Adhesion tends to decrease, which may result in a decrease in moisture resistance. This problem is particularly likely to occur when the IC undergoes a severe process such as soldering.As a result of intensive study by the inventors, the use of component (D) can improve adhesive strength and provide moisture resistance. I have found that my sexual health can also be significantly improved. Therefore, component (D) is indispensable in order to obtain an epoxy resin molding material for encapsulating electronic components that is excellent in reliability such as thermal shock resistance and moisture resistance, and has good moldability.

The inorganic filler of component (E) used in the present invention is not particularly limited as long as the maximum particle size is 200 μm or less, but includes fused silica, crystalline silica, alumina,
One or more types of powders such as zircon, silicon nitride, boron nitride, silicon carbide, calcium silicate, calcium carbonate, beryllia, spinel, and mullite, or beads obtained by spheroidizing these powders can be used. Maximum particle size is 200μm
The following reason is that if the particle size of the filler is coarse, it will clog at the gate portion of the mold during molding, resulting in non-filling defects. The amount of the inorganic filler (E) component is as follows:
Although not particularly limited, it is preferably 40 to 80% by volume, more preferably 60 to 80% by volume from the viewpoint of thermal shock resistance.
80% by volume is desirable.

Furthermore, flame retardants, mold release agents, colorants, and the like can be used as appropriate in the epoxy resin molding material for encapsulating electronic components of the present invention.

A general method for producing molding materials using the raw materials mentioned above is to thoroughly mix a raw material mixture of a predetermined amount using a mixer, etc., then mix the mixture using a hot roll, extruder, etc., cool it, and crush it. By this, a molding material can be obtained.

The most common method for sealing electronic components using the molding material obtained in the present invention is low-pressure transfer molding, but injection molding, compression molding, and casting are also possible.

[Function] The reason why the present invention provides an epoxy resin molding material for encapsulating electronic components with excellent thermal shock resistance, heat resistance, moisture resistance, and moldability is that (A) the epoxy resin and (B) the phenolic resin. A silicone compound having a polyalkylene ether group (C) is used as a flexibilizer in a molding material mainly consisting of a compound having a hydroxyl group and an inorganic filler (E), and further has a ureido group (D). This is presumably due to the use of a silane coupling agent as an adhesion promoter. The silicone compound (C) is a copolymer of polysiloxane, which is incompatible with the base resin, and polyalkylene ether, which is relatively compatible, and is thought to form a phase-separated structure with fine particles dispersed in the base resin. . Due to this, there is almost no decrease in the heat resistance (glass transition temperature, etc.) of the base resin, and flexibility can be effectively achieved. Here, the effect of the polyalkylene ether group is that it has relatively good compatibility with the base resin, so it is thought to work to improve the dispersibility of the silicone compound in the base resin.

Furthermore, the effect of 8 or more, which is considered to prevent the silicone compound from separating and seeping out during molding, is even more effective when the base resin and the silicone compound (C) are mixed in advance by heating. The effect of component (D) is that it can improve the adhesion that has decreased due to silicone modification and maintain good moisture resistance.

[Examples] The present invention will be explained below with reference to two examples, but the scope of the present invention is not limited to these examples.

Example 1 Epoxy equivalent: 200, cresol novolak type epoxy resin with softening point of 70°C: 80 parts by weight, epoxy equivalent: 375,
20 parts by weight of brominated bisphenol A epoxy resin with a softening point of 80°C, hydroxyl equivalent of 106, 48 parts by weight of a phenol novolak resin with a softening point of 83°C, 1.5 parts by weight of triphenylphosphine, 2 parts by weight of carnauba wax, 8 parts by weight of antimony dioxide. Parts by weight, 1.5 parts by weight of carbon black, fused silica powder with a maximum particle size of 150 μm and an average particle size of 15 μm 5
00% by weight and a copolymer of ethyleneoxide and propylenoxide as a silicone compound (mole ratio 2:81 molecules i
2500) and a polyether having an epoxy group as a side group, 40 parts per epoxy, 20 parts by weight of silicone polymer (1) of fZ2500, and 5 parts by weight of trimethoxysilane having a ureido group as a coupling agent. were blended and kneaded using a 10-inch diameter heating roll under conditions of a mixing temperature of about 80° C. and a mixing time of about 10 minutes. Thereafter, 48 parts by weight of the phenol novolak resin of Example 1 and 20 parts by weight of silicone compound (I) were mixed in advance with 0 parts by weight of triphenylphosphine. It was produced in the same manner as in Example 1, except that it was heated and mixed with .5 parts by weight at 150° C. for 3 hours.

Example 3 A silicone compound (TI
) was produced in the same manner as in Example 1, except for using.

Example 4 Same as Example 1 except that 80 parts by weight of the epoxy resin of Example 3 and 20 parts by weight of the silicone compound (H) were heated and mixed together with 0.5 parts by weight of triphenylphosphine at 150°C for 3 hours. It was created in

Comparative Example 1 Example 1 except that the silicone compound (1) of Example 1 and the silane coupling agent having a ureido group were excluded, and 5 parts by weight of the silane coupling agent having an epoxy group was used.
It was prepared in the same manner as .

Comparative Example 2 Comparative Example 1 except that 20 parts by weight of epoxy modified dimethyl silicone oil with an epoxy equivalent of 3000 was used in Comparative Example 1.
It was prepared in the same manner as .

Comparative Example 3 In place of the silane coupling agent having a ureido group in Example 2, a silane coupling agent having an epoxy group was used.
It was produced in the same manner as in Example 2 except that the weight part was used.

Comparative Example 4 In place of the silane coupling agent having a ureido group in Example 4, a silane coupling agent having an epoxy group was used.
It was produced in the same manner as in Example 4 except that the weight part was used.

Table 1 shows the properties of the molding materials obtained in Examples and Comparative Examples.
Table 2 shows details of the characteristic evaluation method.

As a result, the molding materials obtained in Examples 1 to 4 had significantly improved thermal shock resistance and moisture resistance, as well as excellent moldability such as molded product appearance and crispness, compared to Comparative Example 1 without the addition of silicone compounds. There is little decrease in glass transition temperature, which is an indicator of heat resistance.
On the other hand, Comparative Example 2 uses a silicone compound that does not have a polyalkylene ether group, so there are problems with the appearance and texture of the molded product. Furthermore, although Comparative Examples 3 and 4 were modified with a silicone compound having a polyalkylene ether group, they were inferior in moisture resistance because no ureido silane coupling agent was used.

[Effect of the invention]

Claims (6)

[Claims] 1. (A) an epoxy resin having two or more epoxy groups in one molecule, (B) a compound having two or more phenolic hydroxyl groups in one molecule, (C) a silicone polymer having a polyalkylene ether group, ( An epoxy resin molding material for encapsulating electronic components, comprising as essential components D) a silane coupling agent having a ureido group (H_2NCONH-), and (E) an inorganic filler having a maximum particle size of 200 μm or less. 2. The polyalkylene ether group of component (C) is 400 or more
Silicone weight with an average molecular weight of 5,000 to 50,000 and a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. The epoxy resin molding material for electronic component sealing according to claim 1, which is a combination. 3. Component (C) further has an epoxy equivalent of 1500 to 40
The epoxy resin molding material for encapsulating electronic components according to claim 1, which is a silicone polymer having an epoxy group of 0.00. 4. Component (C) further has a carboxyl equivalent of 1500 to
The epoxy resin molding material for encapsulating electronic components according to claim 1, which is a silicone polymer having a carboxyl group of 4,000. 5. Curing acceleration of the compound (B) having two or more phenolic hydroxyl groups in one molecule and the silicone polymer (C) having polyalkylene ether groups and epoxy groups to promote the reaction between the epoxy groups and the phenolic hydroxyl groups An epoxy resin (A) having two or more epoxy groups in one molecule, a silane coupling agent (D) having a ureido group, and an inorganic filler with a maximum particle size of 200 μm or less are mixed in advance by heating in the presence of the agent. A method for producing an epoxy resin molding material for encapsulating electronic components, the method comprising adding and mixing an agent (E). 6. A curing accelerator that promotes the reaction between carboxyl groups and epoxy groups between an epoxy resin (A) having two or more epoxy groups in one molecule and a silicone polymer (C) having a polyalkylene ether group and a carboxyl group. A compound (B) having two or more phenolic hydroxyl groups in one molecule, a silane coupling agent (D) having a ureido group, and an inorganic filler with a maximum particle size of 200 μm or less are mixed in advance with heating in the presence of A method for producing an epoxy resin molding material for encapsulating electronic components, which comprises adding and mixing (E).