JPS6248968B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention aims to provide an epoxy resin composition, particularly a composition suitable for encapsulating electronic components, which has excellent moisture resistance and can yield highly reliable products. Recently, more and more semiconductor devices are being encapsulated with resin, which is superior in mass productivity and can produce products at low cost when compared to conventional ceramic and can encapsulation types. The use of epoxy resins, which have excellent electrical properties, mechanical properties, etc., is increasing. However, semiconductor devices sealed with resins such as epoxy resins are more hygroscopic than ceramic or can-sealed types, and are also less prone to water intrusion through the interface between the resin and the frame. In addition to the problem of large amounts of ionic impurities remaining in these resins, including hydrolyzable Cl, these interact with water and increase the leakage current of semiconductor devices. This causes corrosion of the electrodes and is a major cause of reduced reliability. For this reason, various improvements have been made to the above-mentioned epoxy resins in order to prevent defects caused by insufficient moisture resistance in semiconductor devices sealed with these resins. It has been proposed to remove impurities or add additives to trap ionic substances, but these methods cannot actually completely and reliably remove or trap ionic substances. The disadvantage is that it is impossible to achieve the initial goal. On the other hand, in order to improve the moisture resistance of this type of encapsulation material, the addition of a silane coupling agent is considered to be effective, and as a silane coupling agent for epoxy resin compositions for encapsulating semiconductor devices, epoxy-based Silane, mercapto silane, amine silane, unsaturated hydrocarbon silane, etc. are known.
Examples of the epoxy silane include 3-glycidoxypropyltrimethoxysilane,
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane is used, but since the epoxy groups in these silanes have poor reactivity with epoxy resins, burrs may occur during molding, and In addition to the drawback that electrical properties deteriorate as the amount of epoxy silane added increases, curable epoxy resins containing these epoxy silanes have insufficient adhesion to silicon chips, so semiconductors encapsulated using them The device had the drawback of being prone to failures during humidity tests under harsh conditions. Further, as the mercapto-based silane, for example, 3-mercaptopropyltrimethoxysilane is used, but this has a strong odor and is problematic in practice, and as the amine-based silane, for example,
γ-Aminopropyltrimethoxysilane and N-
(2-aminoethyl)-3-aminopropylmethyldimethoxysilane is used, and compositions containing this have good adhesion to silicon chips.
Although it has the advantage of being less prone to problems such as moisture resistance and corrosion of aluminum electrodes, it has the disadvantage of extremely poor storage stability. Note that vinyltriethoxysilane and 3-methacryloxypropyltrimethoxysilane are used as the unsaturated hydrocarbon silane, but since these do not have a functional group that reacts with the phenol-curable epoxy resin, It is difficult to fully demonstrate its function as a coupling agent. The present invention relates to a curable epoxy resin composition suitable for encapsulating electronic components that solves the above-mentioned disadvantages.
B) 100 to 500 parts by weight of an inorganic filler, and C) General formula R ¹ (-Z-A) _n [where R ¹ is a hydrogen atom or an unsubstituted or substituted hydrocarbon having 1 to 20 carbon atoms, A
is a general formula

[Formula] (R ² , R ⁴ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, R ³ is a divalent hydrocarbon group having 1 to 6 carbon atoms, X is an alkoxy group, alkenyl (oxy group, acyloxy group or hydroxyl group), Z is an oxygen atom or

[Formula] (R ⁵ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms)
0.05 to 10 parts by weight of a coupling agent selected from a group represented by the following formula, m being an integer of 1 to 2, or a hydrolyzate thereof. To explain this, the present inventors have studied various ways to solve the above-mentioned disadvantages regarding curable epoxy resin compositions used for encapsulating electronic parts, and have found that the above-mentioned coupling agent added to epoxy resins is When the silicone compound represented by the formula R ¹ (-Z-A) _n or its hydrolyzate is used, this composition exhibits extremely excellent moisture resistance and also has good storage stability. It has been discovered that there is little corrosion of aluminum wiring in various electronic parts such as semiconductor devices sealed with materials, and therefore semiconductor devices such as ICs, LSIs, transistors, etc. using this composition as a sealant have been found. The present invention was developed after confirming that excellent reliability can be obtained and that this composition can be widely used for various paints, casting, general molding, electrical insulation, laminates, etc. completed. The composition according to the present invention will be explained in detail below. First, the curable epoxy resin as component A) used in the present invention is a curable epoxy resin consisting of an epoxy resin having two or more epoxy groups in one molecule and various curing agents. As the resin, there are no particular restrictions on molecular structure, molecular weight, etc., and various conventionally known resins can be used as long as they can be cured with a phenolic curing agent as described below. For example, epoxy resins synthesized from various novolac resins such as epichlorohydrin and bisphenol, alicyclic epoxy resins, and epoxy resins into which halogen atoms such as chlorine or bromine atoms are introduced can be cited. When used, it is not necessarily limited to only one type, but a mixture of two or more types may be used. In addition, there is no problem in appropriately using a monoepoxy compound in combination with the above-mentioned A) component, and examples of this monoepoxy compound include styrene oxide, cyclohexene oxide, propylene oxide, methyl glycidyl ether, ethyl glycidyl ether,
Examples include phenyl glycidyl ether, allyl glycidyl ether, octylene oxide, and dodecene oxide. Furthermore, various conventionally known curing agents can be used for curing this epoxy resin, such as diaminodiphenylmethane, diaminodiphenyl sulfone, metaphenylenediamine, etc. amine curing agent,
Examples include acid anhydride catalysts such as phthalic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, and those having two or more hydroxyl groups in one molecule such as phenol novolak and cresol novolak. In addition, various curing accelerators such as imidazole or its derivatives, tertiary amine derivatives, phosphine derivatives, cycloamidine derivatives, urea derivatives, etc. are used in combination to accelerate the reaction between the above-mentioned curing agent and the epoxy resin. You may. Typical examples of the inorganic filler that is component B) include crystalline or non-crystalline silica, including Aerosil (trade name manufactured by Degutsusa) and Ultrasil (trade name manufactured by Degutsusa). commercially available ultrafine powdered silica (usually having an average particle size of 1 to 30 μm), Celite (trade name manufactured by John Manville), Imusil (trade name manufactured by Illinois Minerals), crystalline or amorphous quartz powder ( Examples include those having an average particle diameter of usually 1 to 30 μm. However, although these ultrafine silica powders have excellent reinforcing properties, their thickening significantly impairs fluidity, so quartz-based powders are often selected for use in casting or molding.
According to this, various excellent properties can be imparted. Furthermore, regarding this filler, fillers other than the above-mentioned silica-based fillers can be used depending on the use, purpose, etc. of the composition according to the present invention, such as talc, mica, clay, kaolin, carbonate Calcium, alumina, zinc white, baryta, glass balloon, glass fiber, aluminum hydroxide, calcium hydroxide, asbestos, titanium oxide, iron oxide,
Examples include silicon nitride, and two or more of these may be used in combination. If more than 500 parts by weight of the inorganic filler as component B is added to 100 parts by weight of the epoxy resin as component A, it will not only be difficult to disperse, but also have poor processability, low stress, and resistance. Since this may not give satisfactory results in terms of physical properties such as crack resistance, it is preferable to use this in an amount of 100 to 500 parts by weight per 100 parts by weight of component A). Next, the coupling agent as component C) is effective in improving the moisture resistance of the composition of the present invention, and is represented by the formula R ¹ (-Z-A) _n , where R ¹ is a hydrogen atom or Unsubstituted or substituted hydrocarbon group having 1 to 20 carbon atoms, A is a general formula

[Formula] (R ² , R ⁴ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, R ³ is a divalent hydrocarbon group having 1 to 6 carbon atoms, X is an alkoxy group, alkenyl (oxy group, acyloxy group or hydroxyl group), Z is an oxygen atom or

[Formula] (R ⁵ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms), m is an integer of 1 to 2. This R ¹ includes alkyl groups such as methyl group, ethyl group, propyl group, iSO-propyl group, butyl group, t-butyl group, octyl group, and dodecyl group;
Cycloalkyl groups such as cyclopentyl group and cyclohexyl group, alkenyl groups such as vinyl group and allyl group, aralkyl groups such as 2-phenylethyl group, aryl groups such as phenyl group, tolyl group, naphthyl group, xylyl group, or these groups An unsubstituted or substituted monovalent hydrocarbon group or formula selected from groups in which some or all of the hydrogen atoms of are substituted with halogen atoms such as chlorine atoms, cyano groups, etc.

【formula】

【formula】

【formula】

Examples include divalent hydrocarbon groups represented by the general formula A.

In [Formula], R ² and R ⁴ are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms among the same as R ¹ above, and R ³ is a methylene group, ethylene group, propylene group, butylene group. A divalent hydrocarbon group such as a group is exemplified, and X is an alkoxy group, an alkenyloxy group, an acyloxy group, or a hydroxyl group. The coupling agent represented by this formula R ¹ (-Z-A) _n is as follows: These are exemplified by siloxane compounds, but these may also be siloxane compounds obtained by hydrolyzing them,
This siloxane compound also has an effect as a coupling agent. However, this coupling agent preferably has at least one hydrolyzable group remaining in its molecule, and this hydrolyzable group may be a hydroxyl group bonded to a silicon atom. , it may also be a mixture with other hydrolyzable silanes and co-hydrolyzed with them. Regarding the amount of coupling agent used as component C), if it is less than 0.05 parts by weight per 100 parts by weight of the above-mentioned inorganic filler, the effect of improving moisture resistance will not be seen much, and if it is more than 10 parts by weight, Since the glass transition point of the cured product will be low and this will ooze out onto the surface of the cured product, the amount should be in the range of 0.05 to 10 parts by weight, preferably in the range of 0.5 to 6 parts by weight, per 100 parts by weight of the inorganic filler. It is good to do.
It should be noted that the method of adding component C) does not need to be determined in particular;
It may be carried out by adhering to the surface of the inorganic filler. The composition of the present invention can be easily obtained by blending the above-described components A), B), and C), and includes epoxy silane, which has been conventionally used in this type of composition, Silicone compounds such as mercapto silanes and amine silanes, aluminum compounds, alkyl titanate compounds, etc. may be added, and depending on the use and purpose, carbon black, graphite, Fillers such as walrus night, fatty acids, mold release agents such as wax, various coloring agents, flame retardants, flexibility imparting agents, etc. may be added. Next, examples of the present invention will be given. In the examples, all parts are parts by weight, and in the formula, Me
represents a methyl group and Et represents an ethyl group, and the measured values in each example represent the results of measurement by the following methods. (1) Volume resistivity: A disk with a diameter of 100 mm and a thickness of 2 mm is molded (molding temperature: 175°C, molding time: 2 minutes, molding pressure: 70 kg/cm ² ), post-cured at 180°C for 4 hours, and then JIS
The initial resistance value was calculated according to K6911, and the resistance value was further calculated after being left in a pressure tanker (121°C, 2.2 atm) for 200 hours. (2) Bending strength: After forming a bending rod of 100 x 10 x 4 (mm) (forming conditions; same as above) and post-curing at 180℃ for 4 hours, the initial value was measured according to JIS K6911, and 200 to Plescher Kutska (121℃, 2.2atm)
The bending strength was measured after being left for a period of time. (3) Adhesion with Si chips: After mounting a Si chip with a side of 4 mm and a thickness of 0.3 mm on a 14PIN DIP frame, it was molded and sealed with the above composition (molding conditions: (same) and post cured at 180°C for 4 hours. After that, the sealing resin was broken without destroying the Si chip, and the degree of adhesion between the surface of the Si chip and the resin was examined and indicated by ○, △, and ×. 〇…Very good △…Good ×…Poor (4) Formability: A disk with a diameter of 100 mm and a thickness of 2 mm was molded (molding conditions: same as above), and the burrs generated in the gap between the molds during this molding were , and the presence or absence of exudation of the silicone compound onto the surface of the molded product was examined. 〇...Flash, no oozing ×...Flash, oozing Examples 1 to 7, Comparative Examples 1 to 3 70 parts of cresol novolac type epoxy resin (manufactured by Ciba, trade name ECN-1280), phenol novolac resin (Gunei Manufactured by Kagakusha, product name MP-120) 30
1 part triphenylphosphine, 1 part carnauba wax, 1 part carbon black, silica powder
300 parts and 1.5 parts or 2.5 parts of various silicone compounds shown below were kneaded for 3 to 6 minutes using two 8-inch mixing rolls heated to 60 to 100°C, cooled, and then ground.

[Table] Next, the storage stability, adhesion, and moldability of the compositions 1) to 10) obtained in this manner were investigated using the methods described above, and the volume resistivity and bending strength of the cured products were investigated. When measured,
The results shown in Table 1 below were obtained.

[Table] Examples 8 to 13, Comparative Example 4 Epoxy cresol novolak resin with an epoxy equivalent of 220 (manufactured by Nippon Kayaku Co., Ltd., trade name EOCN-102)
64.5 parts, 35.5 parts of tetrahydrophthalic anhydride, 1.5 parts of the coupling agent used in Example 1, 250 parts of fused silica, 1 part of carbon black, 1 part of carnauba wax, 1.5 parts of stearic acid, and C ₁₁ Z
0.8 part of azine (manufactured by Shikoku Kasei Co., Ltd., trade name) was added and treated in the same manner as in Example 1 to prepare Composition No. 11. Further, 25 parts of diaminodiphenylmethane, 1.5 parts of the coupling agent used in Example 1, 230 parts of crystalline quartz powder, and 2 parts of stearic acid were added to 100 parts of the above epoxy cresol novolak resin,
Composition 12 was prepared in the same manner as in Example 1, and further added to 65 parts of phenol volak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name: EPPN) and 35 parts of the phenol volak resin used in Example 1, triphenyl. 1 part phosphine, 1 part carnauba wax, 1 part carbon black, 300 parts fused silica powder and Example 1
The coupling agent used in Example 1 was added in the amount shown in Table 2 below, and treated in the same manner as in Example 1 to obtain Composition 13.
I made ~17. Table 2 Composition No. Amount of coupling agent added (parts) 13 0.5 14 2.0 15 5.0 16 10.0 17 0.04 Next, regarding these compositions No. 11 to No. 17,
When their physical properties were examined in the same manner as in Example 1, the results shown in Table 3 below were obtained.

【table】

[Table] Example 14 After applying aluminum wiring with a film thickness of 1μ and a line width of 10μ to a silicon chip and mounting it on a 14PIN frame, composition 1 used in Examples 1 to 5 and Comparative Examples 1 to 3 was applied. 5 and 8 to 10, post-cured at 180℃ for an hour, and then placed in a pressurizer (140℃ water vapor pressure).
3.1 Kg/cm ² ), and open defects due to corrosion of the aluminum wiring were measured, and the results shown in Table 4 below were obtained. In addition,
The numbers in the table represent the results as number of defectives/parameter.

【table】

Claims (1)

[Claims] 1 A Curable epoxy resin 100 parts by weight B Inorganic filler 100 to 500 parts by weight C General formula R ¹ (-Z-A) _n [Here, R ¹ is a hydrogen atom or a carbon number of 1 to 1] ²⁰ unsubstituted or substituted hydrocarbon groups ^, A is the general ^formula 6 divalent hydrocarbon group, X
is a group represented by an alkoxy group, alkenyloxy group, acyloxy group or hydroxyl group, Z
is an oxygen atom or a group represented by the formula (R ⁵ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms), m is an integer of 1 to 2] or a hydration thereof A curable epoxy resin composition comprising 0.05 to 10 parts by weight of a coupling agent selected from decomposition products.