JPS59108026A - Epoxy resin composition for sealing - Google Patents

Abstract

PURPOSE:To prepare the titled composition having balanced viscosity and fluidity, moldable without flashing, and useful for the sealing of electronic circuit parts, by compounding an epoxy resin with a curing agent, a filler, and ultra-fine amorphous silica powder having specific diameter. CONSTITUTION:The objective epoxy resin composition for sealing can be prepared by mixing (A) an epoxy resin (e.g. phenol novolak-type epoxy resin), (B) a curing agent (e.g. a phenol novolak resin), (C) a filler (e.g. a fused silica having an average particle diameter of 20-40mum), (D) 2-20wt%, based on (A)+(B), of ultra-fine powder of amorphous silica having an average particle diameter of <=20mum, and if necessary (E) an internal releasing agent (e.g. stearic acid), a cure accelerator (e.g. imidazole), a flame-retardant, a surface-treating agent, etc., heating and kneading the mixture, cooling, crushing, tabletting, and carrying out the tablet molding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an epoxy resin composition for sealing used for sealing electronic circuit components such as semiconductor elements.

[Technical background of the invention and its problems] Epoxy resin compositions for sealing are highly reliable materials due to their excellent fluidity, low-pressure moldability, moisture resistance, etc.
It has penetrated the semiconductor field far ahead of other thermosetting resins.

The epoxy resin composition for sealing has extremely low melt viscosity and fluidity so that the objects to be sealed are composed of fine AU and AI wires and AI patterns, etc., so that they will not be deformed or disconnected during sealing molding. Good sexuality is required.
However, if this fluidity is too good, the resin will easily flow out from minute gaps and cause flashing (resin bleed), which is undesirable from the viewpoint of maintenance of the molding die and an increase in the number of man-hours for removing flashing. Furthermore, with the simultaneous progress of high integration, miniaturization, and thinning of ICs, LSIs, etc., in particular, small flat packages with envelopes have thin lead-flakes and mu-walls, and the gap between bottles has increased. automation of the deburring process is often difficult. On the other hand, if the fluidity is too good, voids will occur in the sealed molded product due to the entrainment of air, which is unfavorable in terms of workability and reliability due to deterioration of the moisture resistance of the molded product. Therefore, there is a demand for an epoxy resin composition for sealing that does not generate any firmness or voids and has both fluidity and reliability. In order to solve the above problems, (1) Use a relatively high viscosity raw rice resin (2) Adjust the amount of curing agent or curing accelerator (3) Increase the amount of filler (4) ) Selection of filler particle size, etc. have been studied. (1) tends to cause deformation of ALI and A1 wires, (2) has limits on molding cycles and moisture resistance, (3) has a high viscosity and is easily deformed like (1), and (4) Although it can be improved to some extent, it is not fully satisfactory for all envelopes. Thus, there is a demand for a sealing composition that has a well-balanced viscosity and fluidity.

C. Purpose of the Invention The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide an excellent sealing epoxy resin composition and product that does not cause generation of paris and does not cause deformation of wires, etc. .

[Summary of the Invention] The present invention has been made as a result of intensive research to achieve the above object.
It has been discovered that by blending ultrafine amorphous silica particles in addition to the main filler of conventional particles, it is possible to obtain an epoxy resin composition for sealing that does not generate flakes and does not cause deformation of wires, etc.

That is, in a sealing resin composition containing an epoxy resin, a curing agent, and a filler as main components, the average particle size of the epoxy resin component (epoxy resin and curing agent) is 20 mμ or less (maximum particle size of 50 mμ or less). This is an epoxy resin composition for sealing characterized by containing 2 to 10% by weight of ultrafine amorphous silica powder.

The epoxy resin used in the present invention is not particularly limited, and examples include novolac type epoxy resins and bisphenol type epoxy resins.

Examples of the novolac type epoxy resin include phenol novolac type epoxy resin, cresol novolac type epoxy resin, and halogenated phenol novolac type epoxy resin. These epoxy resins may be used alone or in a mixed system of two or more. Further, as the bisphenol type epoxy resin, a glycidyl ether type epoxy resin, a glycidyl ester type epoxy resin, etc. can be used in combination with the novolak type epoxy resin. These resins have a rating of 70 to 85 according to the JIS ring and ball method.
A material with a softening point of ℃ is preferable.

Examples of curing agents for epoxy resins used in the present invention include phenolic resins, M anhydrides, and polyamines.

Among them, examples of phenolic resin curing agents include phenol novolac resin, Talesol novolac resin, t
Examples include ert-butylphenol novolak resin, nonylphenol novolak resin, and the like.

Examples of acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadic anhydride,
Examples include rutile nadic anhydride, phosuccinic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Examples of the polyamine include meta-phenylene diamine, paraphenyl diamine, dianisidine, 1,4-naphthylene diamine, 4°4'-diaminodiphenylmethane, diaminodiphenylsulfone, and 4,4-diaminodiphenyl ketone.

The main filler used in the present invention has an average particle size of 20 to 4
0 μm fusible silica (A) or crystalline silica (8-)
They can be used alone, in combination with (A) and A'), or in combination with fusible silica having an average particle diameter of 1 to 15 μm <B).

The ultrafine amorphous silica powder used in the present invention has an average particle size of 20 mμ or less (maximum particle size of 50 mμ or less).
It is desirable that the specific surface area is 50111'/(1 or more. The average particle diameter of this ultrafine amorphous silica is 2
If it is less than 0 mμ, if it is larger than this, there will be no anti-fog effect, and a large amount must be added to increase the viscosity. Therefore, it is desirable that the thickness be 20 mμ or less. If the specific surface area is less than 50 m2/(), the anti-padding effect will be reduced or the viscosity will increase, causing problems with wire flow and formability unless the amount is increased.

One type or two or more types may be mixed as long as they have the average particle diameter as described in (a) above. Further, although sufficient effects can be exhibited with this particle size, it is even more effective if the ultrafine particle amorphous silica powder is hydrophobic. It is thought that this can be made hydrophobic by substituting the hydrophilic hydroxyl groups covering the particles with trimedelsiloxyl groups, and that water resistance is improved by making the surface of the particles hydrophobic.

Next, it is desirable that the amount of ultrafine amorphous silica powder is 2 to 10% by weight based on the epoxy resin component (resin and curing agent). If the amount is 2% by weight without grooves, the effect of improving the occurrence of paris is small, and if it exceeds 10% by weight, the melt viscosity increases and causes deformation of the ΔU and AL wires, which is not preferable. Therefore, its range is limited as described above. By incorporating ultrafine amorphous silica powder, which is a finding of the present invention, the occurrence of paris is improved. The reason for this is not necessarily clear, but the resin component that exists between the silica particles, which has a relatively low oil absorption, starts to flow due to the pressure applied during melting, and when it passes through a small gap, the resin and amorphous silica powder are mixed together. It is thought that due to the coexistence of , the thermal conductivity of the part of the part that flows like a film increases, and the reaction with the curing agent and the like proceeds more effectively, thereby reducing the occurrence of part of the part.

In the present invention, it is essential to use at least the above-mentioned ultrafine amorphous silica powder as a filler, but these fillers may further contain other fillers.
Examples include alumina, talc, and clay. The average particle diameter of these fillers can be applied to an extent that does not exceed the above range. As mentioned above, the epoxy resin composition of the present invention contains an epoxy resin, a curing agent, and a filler, but it can also usually contain an internal mold release agent and a curing accelerator.

Examples of the internal mold release agent include long chain carboxylic acids such as stearic acid and palmitic acid, metal salts of long chain carboxylic acids such as zinc stearate and calcium stearate, and waxes such as carnauba wax and montan wax.
As curing accelerators, imidazoles, tertiary amines, phenols, organic metal compounds, etc. are widely used.
Other additives include surface treatment agents for fillers such as silane coupling agents such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane, and antimony oxide. Conventionally known additives such as tuna retardants such as halides and phosphides, and various pigments may also be blended.

To obtain the epoxy resin composition of the present invention, the epoxy resin, curing agent, filler, ultrafine amorphous silica powder, and other additives as necessary are added and mixed uniformly using a mixing roll or an extruder. The mixture is heated and kneaded, cooled, and then pulverized and sized to form Tablef 1 according to a conventional method to obtain an epoxy resin composition for sealing.

[Effects of the Invention] As detailed above, the epoxy resin composition for sealing of the present invention uses a main filler and ultrafine particle amorphous silica in combination, and the ratio of their use is set within a specific range, so it has excellent properties. Its practical value is extremely high due to its well-balanced composition with good fluidity, workability, and no flaking.

[Embodiments of the invention] Next, the present invention will be explained in more detail with reference to Examples.

Examples and Comparative Examples The compositions shown in Table 1 were blended, kneaded for 3 to 5 minutes with a heated mixing roll at 60 to 100°C, cooled and ground, and the viscosity, spiral flow, and par length of the powder were measured. Furthermore, the flow% of the Au wire was measured using a test element using a 16 pin' DIP IC model mold.

The results are shown in Table 1.

Claims (1)

[Scope of Claims] 1. In a sealing resin composition containing an epoxy resin, a curing agent, and a filler as main components, the epoxy resin component (epoxy resin and curing agent) has an average particle diameter of 20 mμ or less (maximum particle size). An epoxy resin composition for sealing, comprising 2 to 10% by weight of ultrafine amorphous silica powder having a diameter of 50 mμ or less. 2. The epoxy resin composition for sealing according to claim 1, wherein the ultrafine amorphous silica is hydrophobic.