JPH0299531A - Inorganic filling material and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title filling material providing a cured material having low stress, excellent cracking resistance, heat resistance, water vapor resistance, etc., by covering the surface of inorganic powder with a thermoplastic elastomer. CONSTITUTION:Inorganic powder (preferably fused silica or ferrite) is fed to a powder blender (e.g., Henschel mixer), preferably a styrene or olefin-based thermoplastic elastomer (0.1-5wt.% thermoplastic elastomer is used based on inorganic filling material) dissolved in a solvent (e.g., toluene) is dropped or sprayed while blending and further the solvent is removed while blending and introducing dried air, etc., to give the aimed filling material. When wetting between the inorganic powder and the thermoplastic elastomer is poor, the surface of the inorganic filling material is preferably treated with a coupling agent (preferably vinyltrimethoxysilane) for use.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention provides an inorganic filler that can be blended with a thermosetting resin such as an epoxy resin to provide a cured product with low stress and excellent crack resistance. and its manufacturing method.

[Conventional technology]

Currently, many semiconductor devices such as ICs and LSIs are sealed using epoxy resin compositions. However, as devices become more highly integrated and larger, and packages become thinner, there is a desire to develop resin compositions that are low in stress and have excellent crack resistance. Examples of defective phenomena include damage to the passivation film due to stress caused by hardening of the resin and thermal stress caused by the difference in coefficient of thermal expansion between the resin and the element, deformation, misalignment, and disconnection of wiring and bonding lines. Further, during solder mounting, vapor pressure caused by rapid vaporization of moisture within the package causes peeling at the interface between the package and the element and cracks in the package.

Furthermore, stress concentrated at the tip of the inorganic filler causes packvation cracks and malfunctions.

Conventionally, in order to reduce internal stress, a method of adding a flexibility imparting agent (for example, synthetic rubber, organosiloxane, etc.) to the epoxy matrix (Japanese Patent Laid-Open No. 61-22305
Thermal expansion can be achieved by lowering the elastic modulus or increasing the amount of inorganic filler added by using methods such as the method of reacting an epoxy resin or a hardening agent with a flexibility imparting agent. Consideration has been given to lowering the rate.

In order to prevent defects during solder mounting, methods such as lower moisture absorption and higher Tt have been considered, but there is no definitive solution. In order to reduce the stress at the tip of the inorganic filler, methods such as making the inorganic filler atomized and spherical are being considered. (Japanese Unexamined Patent Publications No. 62-96567, No. 62-96568) [Problems to be solved by the invention] Conventional inorganic fillers can reduce thermal stress, but have poor crack resistance and heat resistance. This had the disadvantage of causing a decrease in water resistance, moisture resistance, and fluidity.

The purpose of the present invention is to provide an inorganic filler that can be applied to LSI and VLSI and can provide a resin composition with low stress, excellent crack resistance, and no decrease in heat resistance or moisture resistance, and a method for producing the same. be.

[Means to solve the problem]

The inorganic filler according to the present invention has a surface coated with a thermoplastic elastomer. The manufacturing method is such that while mixing the inorganic powder using a powder mixing device, a thermoplastic elastomer solution is dripped or sprayed, and the solvent is removed while being mixed.

It is defined as a fee. Generally, it is a block or graft polymer consisting of a soft segment that exhibits rubber elasticity and a hard segment that acts as a crosslinking point at room temperature.

Thermoplastic elastomers that can be preferably used in the present invention include those whose soft segments are composed of hydrocarbons having conjugated 21 bonds (diene-based), those made of water strings, long-chain aliphatic hydrocarbon-based, etc. can be mentioned. Furthermore, those in which part or all of the hydrogen atoms of the above-mentioned hydrocarbons are replaced with fluorine atoms (fluororubber), and siloxane systems such as polydimethylsiloxane and polyphenylmethylsiloxane may also be used. Examples of hard segments include hydrocarbons that melt in the range of 70°C to 250°C (for example, polyolefins such as polystyrene and polypropylene), fluororesins in which some or all of their hydrogen atoms have been replaced with fluorine atoms, Copolymers of polydiphenylsiloxane and polydimethyl-spread polymethylphenylsiloxane are used.

The thermoplastic elastomers currently on the market are polycrethane-based, polyester-based, and anti-refin-based.

It can be roughly classified into styrene type, and as mentioned above, styrene type or olefin type is preferable from the viewpoint of heat resistance and moisture resistance. Specific examples include Toughbrane (Asahi Kasei), Toughtic (Asahi Kasei), Kaliflex (Shell Chemical), Clayton G (Shell Chemical), and Nisprene EPR.
(Sumitomo Chemical), Milastomer (Mitsui Petrochemical), and TSR Temora/(Japan Synthetic Rubber).

The amount of thermoplastic elastomer used above is the amount of inorganic filler used. It is preferable that the amount is within the range of 0.1 to 5% by weight.

If the amount is too less than the above range, the effect will not be sufficiently expressed.
If it is too large, the dispersibility decreases (the filler aggregates) and the strength decreases, so it is desirable to select it within the above range.

On the other hand, the inorganic material constituting the inorganic filler is not particularly limited, but examples of those that can be preferably used in the present invention include fused silica.

Examples include crystalline silica, spherical silica, alumina, boron nitride, magnesia, gyric carbide, silicon nitride, glass fiber, and ferrite. These are usually used in the form of powder, and two or more of these can be used in combination if desired.

The inorganic filler coated with a thermoplastic nidistomer in the present invention can be preferably produced, for example, by the following method.

A desired amount of inorganic powder is added to a mixing or stirring means such as a Henschel mixer or a N-Dige mixer, and while mixing, it is added to a solvent such as toluene, xylene, C-hexane, or tetrahydrofuran at an i.
Drop or spray the above thermoplastic elastomer dissolved in 'ii%. The concentration of the solution is adjusted so that the viscosity matches the mounting method. The solvent is removed by introducing dry air or nitrogen gas while mixing or by heating to 30 to 70°C. If the solvent is not removed while mixing, agglomeration will occur.
This causes a decrease in strength.

In cases where the wettability between the inorganic powder and the thermoplastic elastomer solution is poor, etc., the surface of the inorganic filler is pretreated with a coupling agent or a silane compound that imparts hydrophobicity such as phenyltrimethoxysilane or methyltrimethoxysilane. That's good.

The above coupling agent is not particularly limited, but
Examples of those that can be preferably used include t, vinyltrimethoxysilane, vinyltriethoxysilane, γ
- Silane coupling agents such as methacryloxypropyltrimethoxysilane, γ-mercaptoglobiltrimethoxysilane, and inglobiltrinstearyl silane.The amount of this coupling agent used depends on the type of inorganic powder used, but it is usually packed It is preferably 0.05 to 2% by weight based on the material.

The inorganic filler whose surface is coated with a thermoplastic elastomer obtained by pressing as described above can be used by blending it with a resin or an epoxy resin. It can provide a cured product without deterioration in moisture resistance, and can be expected to yield good results when applied to highly reliable sealing materials for various semiconductor devices such as LSI and VLSI, various electronic components, and electrical equipment. be.

The type of resin mentioned above is not necessarily limited, but epoxy resin can be particularly preferably used.

As such epoxy resin, various types of epoxy resins can be used, such as novolac type, Talesol novolac type, bis A type, bis F type, etc. In addition to these epoxy resins, it is also possible to use Jl-formed epoxy resins such as brominated novolak epoxy resins and brominated bisphenol A epoxy resins, if necessary. These epoxy resins can be used alone or in combination of two or more.

As the curing agent, it is possible to use, for example, phenols such as phenol novolanc, acid anhydrides such as tetrahydrophthalic anhydride, and amines such as diaminodiphenylmethane. The amount used is not particularly limited, but 0.7 to 1.3 equivalents based on the epoxy resin is suitable.

As the curing accelerator, imidazole or imidazole derivatives, organic phosphine derivatives, tertiary amines, etc. can be used as required. Usually, it is preferable to add 0.05 to 4.0 parts by weight per 100 parts by weight of the epoxy resin.

In order to obtain a resin composition such as an epoxy resin using the inorganic filler coated with the thermoplastic elastomer according to the present invention, known mixing devices used in the production of conventional resin compositions, such as hot rolls, It can be easily prepared using a kneader, extruder, etc. as appropriate. In this case, ¥! The amount of the inorganic filler added to the fat is not limited and should be adjusted as desired, but it can usually be arbitrarily selected within the range of 50 to 95% of the total composition. .

When an epoxy resin is used as the resin, the thermoplastic elastomer of the present invention exists at the interface between the epoxy resin and the inorganic filler, which have significantly different coefficients of thermal expansion, and acts as a stress relaxation layer. Ships do not necessarily need to be chemically bonded. However, from the viewpoint of improving moisture resistance and/or heat resistance, thermoplastic elastomers having organic groups, carboxyl groups, carboxylic acid anhydride amine groups, epoxy groups, hydroxyl groups, etc. that react with matrix resins are preferred.

Moreover, the inorganic filler coated with a thermoplastic elastomer can also be used as a part of the filler mixed with the resin. That is, out of all the inorganic fillers, only those with a specific particle size can be used by being coated with a thermoplastic elastomer.

Furthermore, in addition to K, a coloring agent such as carbon black, an internal mold release agent such as carnauba wax, and a flame retardant such as antimony trioxide may be added as necessary.

[For production]

The thermoplastic elastomer that coats the surface of the inorganic filler in the present invention is a resin material (IJ) in the resin composition.
It acts as a stress reliever at the interface between the wax and the inorganic filler, and also lowers the elastic modulus of the entire system. The effect of lowering the elastic modulus is greater than that of a system in which the same amount of elastomer is dispersed in a matrix (sand inch effect). Furthermore, while it is usually difficult to control the particle size and disperse elastomers in a matrix,
The dispersed particle size can be controlled simply by selecting the particle size of the inorganic filler.

Thermoplastic elastomers are made of thermosetting rubber that is processed by hot-gathering or fillers (
While the strength would be very low without carbon black), it is characterized by high strength without the need for galvanization and without filling. Therefore, it does not cause a decrease in strength or crack resistance unlike other rubber dispersion systems or modified systems using liquid rubber. When a hydrocarbon type thermoplastic elastomer is used, such as a styrene type or an olefin type, the moisture resistance does not deteriorate because of its strong water repellency. Furthermore, by using a system that does not contain unsaturated bonds, heat resistance is not impaired.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples; however, the present invention is not limited to these Examples.

Example 1 Toughtic M-1913 (
(manufactured by Kasei Kasei) was dissolved in toluene to prepare a 10% by weight solution. Predetermined amount of spherical silica BF100 (Mitsubishi Gold 1!!(
Co., Ltd.) using a Ledeige mixer (made by Ledeige Co., Ltd.) at a mixer rotation speed of 20 orpm and a chopper rotation speed of 500O.
The elastomer solution was added dropwise to the silica in an amount of 103 Iz% while stirring at rpm. Thereafter, while introducing dry air, the mixture was mixed and dried while heating the mixer to 50°C. After about 30 minutes, the mixer temperature was cooled to room temperature to obtain thermoplastic elastomer-coated spherical silica.

The resulting elastomeric spherical silica was coated with epoxy resin, curing agent, etc. in the formulation shown in Table IK using a hot roll C manufactured by Eto Seisakusho 6.
900 (:.

The mixture was kneaded for about 20 minutes to prepare a resin composition. The catalyst was added 3 minutes before the crosstalk ended.

Example 2 A spherical silica was prepared in the same manner as in Example except that the spherical silica was treated in advance with o) Hf% phenyltrimethoxysilane. The silane treatment was carried out by a dry direct treatment method using a Lodeige mixer.

Example 3 It was prepared in the same manner as the actual M9flJ2 except that vinyltrimethoxysilane was used as the silane compound.

Example 4 A thermoplastic elastomer was prepared in the same manner as in Example 3 except that Nisbrene EPR (manufactured by Sumitomo Chemical Co., Ltd.) was used.

Example 5 Toughtic M1913015 as thermoplastic elastomer
This was carried out in the same manner as A3, except that a heavy i% acid solution was used and a 20 heavy acid solution was used for the silica.

Example 6 The elastomer-covered silica of Example 5 was added to 50mf of the total silica amount.
It was prepared in the same manner as Example X except that L% was used.

Example 7 Aluna beads C, which is spherical alumina, as an inorganic filler
It was prepared in the same manner as in Example 1 except that B-AIO (manufactured by Showa Denko) was used.

Comparative Example 1 Spherical silica BF100 without coating with thermoplastic elastomer
It was prepared in the same manner as in Example 1 except that .

Comparative Example 2 A resin composition was prepared by not covering the spherical silica BF100 with a thermoplastic elastomer, Toughtic M-1913, but adding the same amount as in Example 1 during kneading with a heated roll.

Comparative Example 3 A sample was prepared in the same manner as in Example 1 except that a 10% by weight toluene solution of Toughtic M-1913 was used in an amount of 0.5% by weight of the filler.

Comparative Example 4 A sample was prepared in the same manner as in Example 3 except that a 15% by weight toluene solution of Toughtic M-1913 was used in an amount of 40% by weight based on the silica.

Comparative Example 5 A sample was prepared in the same manner as in Example 1, except that epoxy-modified silicone oil 5Fs4zx (manufactured by iL Resilicone) was melt-mixed with an epoxy resin in advance.

[Sample molding and evaluation]

Using the resin compositions prepared in 11 il in Examples 1 to 7 and Comparative Examples 1 to 5, transfer molding was performed at 175° C. for 90 seconds, and post-curing was performed at 175° C. for 7 hours.
A physical property test piece and an element for evaluating moisture resistance were obtained.

The glass transition point was determined using a thermophysical tester TMS-7 model.
The coefficient of thermal expansion was determined by m+j and determined from its inflection point.

Bending strength and bending elastic modulus were determined according to JIS K-6911K.

Moisture resistance was evaluated by subjecting the evaluation element to a Breller force test at 130° C. and 2.7 atm, and determining the time required for the disconnection failure rate of the aluminum wiring to reach 50%.

Soldering resistance was determined by subjecting it to a pressurization force test at 120°C and 2 atm for 24 hours before conducting the above humidity test.
It was immersed in solder at 0° C. for 30 seconds and evaluated in the same manner.

Thermal shock resistance was determined by a thermal shock cycle test in which the evaluation element was immersed in solder at 260'C for 30 seconds and then immersed in liquid nitrogen (-196°C) for 30 seconds. Those that reach the target are considered defective, and the defective rate is 5.
Evaluation was made based on the number of cycles reaching 0%.

Heat resistance was evaluated by aging the evaluation element at 200 DEG C. for 500 hours, subjecting it to one cycle of heat, followed by a moisture resistance test, and evaluating the rate of defective wire breakage after 200 hours.

Fluidity was determined by observing the flow rate of the gold bonding wire of the evaluation element using soft X-rays, and those with significant deformation were judged as defective.

In addition, it was confirmed that the surface of the obtained inorganic filler was covered with the thermoplastic elastomer by measuring the contact angle of the samples obtained in each of the above examples.

〔Effect of the invention〕

As described above, according to the present invention, since the surface of the inorganic filler is covered with a thermoplastic elastomer, the resin has low stress and excellent crack resistance, and has no decrease in heat resistance or moisture resistance. It has the effect of providing a composition.

Claims (2)

[Claims] (1) An inorganic filler whose surface is coated with a thermoplastic elastomer. (2) Inorganic filling whose surface is coated with thermoplastic elastomer, characterized by dropping or spraying a solution of thermoplastic elastomer while mixing inorganic powder using a powder mixing device, and removing the solvent while further mixing. Method of manufacturing wood.