JPS6226651B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermosetting resin composition, and particularly to a thermosetting resin composition containing an epoxy resin as a main ingredient and used for encapsulating electronic components. The encapsulation of electronic components such as semiconductor devices is shifting from ceramics and cans to resin encapsulation methods, which are mass-producible and low-cost. The use of epoxy resins is increasing because of their superior properties. However, with regard to these semiconductor devices, as semiconductor elements have become larger due to higher integration, the packages that seal them have become smaller and thinner. There are disadvantages in that the stress generated during curing deteriorates the semiconductor properties of the device and causes accidents such as destruction of the passivation film and the device.
Another drawback is that when this seal is made particularly compact and thin, cracks can easily form in the resin layer due to heat cycles or soldering, and if the resin layer is made thinner, moisture can Since it easily passes through the layers and reaches the surface of the semiconductor element, there is a disadvantage that aluminum electrodes and the like are corroded. On the other hand, most of this resin sealing is done by transfer molding in terms of mass production and workability, and as a result, it has become common practice to mold a large number of 200 to 1,000 pieces, but this is not possible with money. The disadvantage is that mold release agents, which are used to improve the release of resin from the mold, can accumulate on the mold surface, contaminating the mold, and the mold must be cleaned to remove this contamination. A process of cleaning with resin is required. The present invention relates to a thermosetting resin composition that solves these disadvantages, and includes (A) 100 parts by weight of a thermosetting epoxy resin, and (B) a perfluoroalkyl group containing 5 or more fluorine atoms. It is characterized by comprising 0.1 to 20 parts by weight of at least one organopolysiloxane and 50 to 500 parts by weight of (C) an inorganic filler. To explain this, the present inventors have conducted various studies on measures to improve the physical properties of resin compositions for encapsulating electronic components that have epoxy resin as the main ingredient. When an organopolysiloxane having a group is added, the impact resistance of the resin sealing layer molded with this composition is improved, and since it is said to have water repellency, it has excellent moisture resistance. It was discovered that the mold release effect prevents mold contamination, and therefore resin sealing that does not cause cracks even during heat cycles and soldering, and does not cause electrode corrosion due to moisture intrusion. After confirming that a layer could be obtained, the present invention was completed by conducting research on the type and amount of organosiloxane added. The thermosetting epoxy resin as the main component constituting the composition of the present invention may be a known one conventionally used in this type of composition, and has at least one, preferably two or more epoxy groups in the molecule. Examples include those consisting of epichlorohydrin and bisphenol A, or resins synthesized from various novolak resins, alicyclic epoxy resins, and epoxy resins containing halogen atoms such as chlorine atoms and bromine atoms. This is its molecular structure,
There is no particular restriction on the molecular weight, and it may be two or a mixture of two or more thereof. Naturally, a curing agent is used in conjunction with this epoxy resin, and these include amine-based curing agents such as diaminodiphenylmethane, diaminodiphenyl sulfone, and metaphenylenediamine, phthalic anhydride, pyromellitic anhydride, and benzophenone anhydride. Acid anhydride curing agents such as tetracarboxylic acid, phenol novolak curing agents having two or more hydroxyl groups in the molecule such as phenol novolak and cresol novolak, various imidazole derivatives, tertiary amine derivatives, cycloamidine Examples include derivatives, phosphine compounds, and catalytic curing agents such as boron trifluoride. Next, the organopolysiloxane as component B) in the composition of the present invention is required to contain at least one perfluoroalkyl group in its molecule, and this perfluoroalkyl group contains a fluorine atom. It is preferable to include at least five, and examples thereof include the following. CF ₃ CF ₂ CF ₂ ―, CF ₃ (CF ₂ ) _o CH ₂ CH ₂ ―, CF ₃
(CF ₂ ) _o CH ₂ CH ₂ S―, CF ₃ (CF ₂ ) _o CF ₂ CF ₂ COO
--, C ₇ F ₁₅ CH _{2 CH 2} O—, this organopolysiloxane having a perfluoroalkyl group may have a linear, branched _{, or three-dimensional structure, R 13} ^SiO _0.5 units, ^R22SiO _{_}
Units, R ³ ₁ SiO _1.5 units, SiO ₂ units (where R ¹ _,
R ² and R ³ are composed of an arbitrary composition ratio of a monovalent organic group or an organic group having one or more fluorine atoms, and this organic group is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, etc. Alkenyl groups such as vinyl groups and allyl groups, aryl groups such as phenyl groups and tolyl groups, cycloalkyl groups such as cyclohexyl groups, and some of the hydrogen atoms bonded to the carbon atoms of these groups are replaced by halogen atoms or cyano groups. It may be selected from groups substituted with such as methoxy groups, alkoxy groups such as ethoxy groups, and functional groups such as amino groups, epoxy groups, thiol groups, hydroxyl groups, and carboxyl groups. Further, the viscosity of this organopolysiloxane is not particularly defined, and it may be a low-viscosity or high-viscosity liquid or a solid having a softening point, and examples thereof include the following. (1) Linear polysiloxane (2) Granulated polysiloxane (3) Three-dimensional structure polysiloxane [R _f in the above represents a perfluoroalkyl group] The amount of this organopolysiloxane added to component (A) is 0.1 parts by weight per 100 parts by weight of component (A).
If it is less than 20 parts by weight, the effect of improving the moisture resistance of the sealing resin layer made from this composition and the releasability from the mold will be small; if it is more than 20 parts by weight, it may bleed onto the surface of the molded product or the resin interface This will reduce the adhesion between the lead and the lead, so this should be 0.1 to 20 parts by weight per 100 parts by weight of the epoxy resin as component (A).
The amount is preferably 0.5 to 10 parts by weight. Note that if the perfluoroalkyl group has 5 or less fluorine atoms, this organopolysiloxane will not exhibit sufficient mold release properties, so it is necessary to have 5 or more fluorine atoms. There is. Further, the inorganic filler as component C) may be a known one, such as dry silica, wet silica, fused silica powder, crystalline quartz powder, glass fiber, alumina, calcium carbonate, magnesite, zinc white, clay, kaolin, Examples include talc, mica, asbestos, carbon black, etc., and these may be used alone or in combination of two or more thereof. The amount used should be 50 parts by weight or more per 100 parts by weight of the epoxy resin as component A), but if it is too large, it will be difficult to disperse it and the processability will be poor, making it difficult for the molded product to have low quality. Since it will lack stress and crack resistance, it is preferable to limit it to 500 parts by weight. The composition of the present invention can be obtained by uniformly mixing the above-mentioned components (A), (B), and (C) using a mixer, roll, etc., and if necessary, colorants, coupling agents, Known additives such as antioxidants and flame retardants may also be added. This composition contains the above-mentioned organosiloxane containing a fluorine atom-containing functional group, and this organosiloxane has excellent heat resistance and will not deteriorate even if left in a high-temperature atmosphere for a long time. is suitable as a mold release agent for curable resins, and furthermore has excellent water repellency and works as a flexibility imparting agent for various resins, so the composition of the present invention contains it. The sealing resin layer obtained by molding the product is free from cracks even during heat cycles and soldering, and its water repellency prevents moisture from entering, so there is no corrosion of the electrodes. Furthermore, since this composition itself has mold releasability, it is advantageous in that there is no contamination of the mold by the mold release agent. Next, examples of the present invention will be given, in which parts are by weight, and the various physical properties are the results of measurements or observations made by the following methods. (Cold heat cycle test) 0.35mm thick silicon wafer 16mm x 4.5mm
This was cut into rectangles and glued to a 14-pin IC frame (42 alloy), which was then transfer molded using each molding material at 160°C for 2 minutes, and then post-cured at 180°C for 4 hours. This was then cooled at −55°C for 30 minutes at 180°C.
A cold/hot cycle treatment of heating at ℃ for 30 minutes was performed, and the number of cycles until the defective rate due to cracking of the molded product decreased to 50% was measured. (Stress measurement) Piezoresistance whose resistance value changes due to stress is 3mm.
It is formed on a square silicon chip, wire-bonded to a 14-pin IC frame with gold wire, connected to an external electrode to measure the initial resistance value (Ro), and then molded at 160℃ and 70Kg/cm ² . The resistance value (R) after resin sealing under molding conditions of 3 minutes was measured, and the R-Ro/Ro value was calculated, which was taken as the resin stress. (Hardness when heated) Each molding material was
It was molded at 175°C for 2 minutes, and the hardness was measured immediately after disassembling the mold using a Barcol hardness tester JYZ-935. (Mold contamination) Using a mold for molding a 100mmφ x 2mm thick disc, we performed 100 continuous moldings at 175°C for 2 minutes, and then checked with the naked eye the degree of cloudiness on the mold surface. Examined. (Moisture resistance = aluminum electrode corrosion resistance) A test element for aluminum corrosion measurement was bonded to a 14-pin IC lead frame, various molding materials were molded onto this, post-cured at 180℃ for 4 hours, and then 140℃ and 3.1 atm. The corrosion of the aluminum electrode was examined by leaving it in a steam atmosphere. (General physical properties) The bending strength, bending modulus, glass transition point,
Volume resistivity was measured. Note that this volume resistivity is
The measured values at 100°C () and the measured values after being left in a steam atmosphere for 100 hours () are shown. Example 1 An epoxy resin composition consisting of 63 parts of orthocresol epoxy novolac resin, 32 parts of phenol novolac resin and 5 parts of prominated epoxy novolac resin was added with the following organopolysiloxanes A to G in Table 1. Fused silica powder with the indicated amount 250
parts, and antimony trioxide, γ-glycidoxytrimethoxysilane, carbon black, triphenylphosphine, diazibicyclo[5,4,0]undecene (DBU), in the amounts shown in Table 1.
When a composition was prepared by adding carnauba wax and the physical properties were tested, the results shown in Table 2 were obtained, and the results regarding moisture resistance were as shown in Figure 1. was gotten.
Note that sample No. 13 shows a comparative example.

【table】

【table】

【table】

[Table] Example 2 Organopolysiloxanes C and F used in Example 1, fused silica, and γ-glycidoxysiloxane were added to an epoxy resin composition consisting of epoxy novolak resin, tetrahydrophthalic anhydride, and diaminodiphenylmethane. A composition was prepared by blending citrimethoxysilane, carbon black, imidazole, and carnauba wax in the amounts shown in Table 3, and various physical properties of these were investigated.
The results shown in Table 3 were obtained. Note that Samples Nos. 16 and 17 are comparative examples in which no organopolysiloxane was added.

【table】

[Table] Comparative example: 63 parts of cresol epoxy novolac resin, 32 parts of phenol novolac resin, 5 parts of prominated epoxy novolac resin, formula 2 parts of perfluoroalkyl group-containing organopolysiloxane shown by, 250 parts of fused silica powder, 10 parts of antimony trioxide, 1.2 parts of γ-glycidoxytrimethoxysilane, 1.0 part of carbon black, and 1.0 part of triphenylphosphine. Composition No. 18 was prepared by kneading, and the perfluoroalkyl group-containing organopolysiloxane of Composition No. 18 was mixed with the following formula: Composition No.
I made 19. Next, we examined the moisture resistance of compositions No. 18 and 19, as shown in Figure 2, and found that these compositions had a fluorine content of 5 or less in the perfluoroalkyl group. It was confirmed that this composition had poorer moisture resistance than Composition No. 4 containing 5 or more perfluoroalkyl groups.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 both show test results diagrams of the corrosion resistance of aluminum electrodes showing the moisture resistance of molded articles for encapsulating electronic components made from the composition of the present invention.

Claims (1)

[Scope of Claims] 1 A. Thermosetting epoxy resin 100 parts by weight B. Organopolysiloxane having at least one perfluoroalkyl group containing 5 or more fluorine atoms 0.1 to 20 parts by weight C. Inorganic filler 50 to 20 parts by weight 500 parts by weight of a thermosetting resin composition.