JPH0431311A - Spherical silica, its production, epoxy resin composition and cured product thereof - Google Patents

Abstract

PURPOSE:To obtain spherical silica having improved compatibility and adhesive strength to resins and suitable for the sealing of semiconductor by spraying a suspension of amorphous silica having specific particle diameter and calcining the obtained spherical granules to form calcined particles having specific pore form. CONSTITUTION:A suspension containing fine particles of amorphous silica having a weight-average particle diameter of <=10mum is granulated by spray-drying process to form spherical silica, which is calcined at 1000-1300 deg.C to obtain the objective spherical silica containing 0.02-0.15ml/g of fine pores having pore diameter of 0.01-0.1mum. Preferably, the content of alkali metal, alkaline-earth metal, halogen element and transition metal element in the spherical silica is <=1ppm each and that of radioactive elements is <=1ppb each. An epoxy resin composition filled with the spherical silica has excellent fluidity, high flexural strength and excellent crack resistance after soldering in moisture- absorbed state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to spherical silica having pores of controlled diameter and volume, specifically pores having a diameter in the range of 0.01 to 0.1 μm. and the volume of those pores is 0.0
2~0.15mj! The present invention relates to spherical silica and its manufacturing method, as well as epoxy resin compositions and cured products thereof.

[Conventional technology]

In recent years, with the increase in the density of integrated circuits, the proportion of the chip area occupied in the encapsulating resin composition (hereinafter referred to as encapsulating material) of high-density integrated circuit electronic components has increased, and the thickness of the package has also been reduced. It's progressing. For this reason, requirements for the quality of the encapsulant are becoming increasingly strict so that the chip can be protected with a thin encapsulant.

Such requirements include, first of all, heat stress resistance.

In other words, thermal stress is generated due to the difference in thermal expansion coefficient between the silicon chip and the encapsulant.
are required to do so. Therefore, in order to bring the coefficient of thermal expansion of the sealing material as close as possible to that of the silicon chip, a method has been adopted in which silica, which has a low coefficient of thermal expansion, is added to the resin as much as possible as a filler.

By the way, as filler silica, crushed silica produced by crushing and having an irregular shape and sharp corners has been widely used. However, such a sealing material with a high filling rate of crushed silica has an increased viscosity and deteriorates fluidity during molding, making it impossible to obtain a homogeneous package having predetermined characteristics. Furthermore, crushed silica having sharp edges may wear out the molding die and may penetrate the protective film on the chip surface and damage the aluminum wiring on the chip. For this reason, there is a need for spherical silica without sharp edges that does not reduce the fluidity of the encapsulant, and various proposals have been made to use such spherical silica as a filler in encapsulants. .

Conventionally, methods for producing spherical silica used as a filler for such sealants include (1) a method of melting crushed silica in a flame (for example, Japanese Patent Application Laid-open No. 145613/1983); (2) a method of melting a crushed silica in a flame; A method in which a sol-like solution obtained by hydrolyzing a silicate is sprayed into a heating medium, dried and granulated, and then melted in a flame (for example, JP-A-58-2233), (3) Silicon alkoxide A method of removing alcohol from a partial condensate sol obtained by hydrolyzing a silica gel, dispersing it in water and precipitating it, and firing the resulting silica gel (for example, Japanese Patent Application Laid-Open No. 63-225538
Publication No. 2), etc. have been proposed.

In the calcination of silica in these conventional techniques, conditions have been adopted in which calcination proceeds completely until the pore volume becomes 0.01 ml/g or less, taking into consideration the hydrophobicization of the silica and the strength of the fired product. .

[Problem to be solved by the invention]

However, each of the above-mentioned conventional methods for producing spherical silica has the following problems.

That is, the particles obtained by method (1) or (2) have a weak adhesive force with the resin because their surfaces are too smooth.
It is not suitable as a filler for sealants, and the flame melting method has economic limitations because it consumes large amounts of expensive hydrogen and oxygen. Furthermore, method (2) requires expensive raw materials and requires treatment of wastewater containing organic matter derived from the raw materials.

On the other hand, in method (3), an attempt is made to increase the adhesive strength between the filler and the resin when used as a filler for a sealant by giving the surface of the silica particles a cantaloupe-like unevenness. , it still has not reached a sufficient level compared to crushed silica.

In this way, the previously proposed spherical silica can prevent the fluidity of the encapsulant from deteriorating when the filling rate in the encapsulant is increased, but it has poor compatibility with the resin and has poor adhesive strength. It is inferior in quality and can easily cause the package to crack. For these reasons, there is a strong demand for improvements in spherical silica as a filler for sealants.

Therefore, the object of the present invention is to achieve a resin filling rate of 60 to 60.
Even when blended in a large amount in the range of 90% by weight, the fluidity of the encapsulant is unlikely to decrease, and it is compatible with the resin, has high adhesive strength, and increases the strength of the encapsulant. The present invention provides spherical silica, a method for producing the same, an epoxy resin composition suitable for semiconductor encapsulation, and a cured product thereof.

[Means and effects for solving the problem] As a result of intensive studies to achieve the above object, the present inventors have found that by controlling the diameter and volume of pores possessed by spherical silica, a sealing material can be developed. It was discovered that spherical silica suitable for use as a filler material can be obtained.

In general, when firing silica in conventional techniques, the pore volume is reduced to 0, taking into account hydrophobicization of the silica, strength of the sintered body, etc.
．． Conditions are adopted that allow the firing to proceed completely until the temperature reaches 01 sIJ/g or less.

In contrast, the present inventors found that silica particles having pores large enough to allow the sealing resin to penetrate do not actually improve the strength of the sealed body when used as a filler for the sealant. Considering this, we investigated the relationship between the pore diameter and pore volume possessed by silica particles as a filler and the strength of a sealed body obtained by molding a sealing material containing such a filler.

As a result, surprisingly, there is a close relationship between the pore volume of silica particles as a filler and the strength of the sealed body.
It was found that the larger the pore volume, the greater the strength of the sealed body. Furthermore, as a result of intensive research based on this knowledge, spherical granulated silica obtained by spray drying a suspension of amorphous silica with a weight average particle size of 10 μm or less was dried at a temperature of 1000 to 1300°C. By firing within the range for an appropriate time, the diameter becomes 0. Spherical silica having a pore volume of 0.02 to 0.15 mJ/g, which is in the range of O1 to 0.1 μL, is obtained, and this spherical silica has excellent properties as a filler for a sealant. However, the inventors have discovered that the above object can be effectively achieved, and have completed the present invention.

Therefore, the present invention, as a first invention, has pores with a diameter in the range of 0.01 to 0.1 μm, and the volume of the pores with the diameter in the range is 0.02 to 0.1 μm. Provided is spherical silica in the range of 15 mff1/g.

In addition, as a second invention, spherical granulated silica is obtained by spray drying a suspension of amorphous silica having a weight average particle size of 10 μ■ or less, and then the spherical granulated silica is heated at a temperature of 1000 to
Fired in the range of 1300℃, the diameter is 0.01~0.1
It has pores in the range of the μ intestine, and the volume of the pores with a diameter in the above range is 0.02 to 0.15 sj! Provided is a method for producing spherical silica, characterized by obtaining spherical silica having a weight of 1/g.

Furthermore, as a third invention, there is provided an epoxy resin composition characterized by containing the above-mentioned spherical silica as a filler.

Furthermore, as a fourth invention, there is provided a cured epoxy resin product obtained by curing the above-mentioned epoxy resin composition.

In the present invention, spherical silica is defined as one silica particle having a ratio of the minimum diameter to the maximum diameter of 1 to 0.
6.

The present invention will be explained in more detail below.

As mentioned above, the spherical silica according to the first aspect of the present invention has pores with a diameter in the range of 0801 to 0.1 μm,
And the volume of those pores is 0.02 to 0.15 sI!
/g.

Here, the spherical silica of the present invention is effectively used as a filler in an epoxy resin composition that is suitably used as a sealant, but the spherical silica as a filler for a sealant has a The diameter of the pores that contribute to the strength of the stopper is in the range of 0.01 to 1 μm. Pore diameter is 0.01
If the diameter is smaller than μ■, even if moisture can penetrate into the pores, it becomes difficult for the resin to penetrate. Further, the presence of pores with a diameter smaller than 0.01 μm is not preferable as it indicates that the degree of sintering is insufficient, and such spherical silica has low strength and cannot be used. On the other hand, pores with a diameter larger than 0.1 μm hardly contribute to improving the strength of the sealed body.

Next, regarding the pore volume in the above range, the value is 0.
If it is smaller than 0.02mf/g, there is almost no contribution to improving the strength of the sealing body, while if it is larger than 0.15ml/g, it will significantly increase the strength of the sealing body, but the flow of the sealant during molding will increase. It is not suitable as a filler for sealants because it significantly reduces the properties.

Therefore, the reason why both the fluidity during molding of the encapsulant and the strength of the obtained encapsulant are good is that the spherical silica used as the filler for the encapsulant and L7 is 0.01 to 0.1 μm. Mackerel, more preferably has pores with a diameter in the range of 0.02 to 0.08 μm, and the volume of these pores is 0.02 to 0.15 s!
! /g, more preferably 0.03-0.1+wI! /g
This is the case when the range is within the range of .

The method for producing spherical silica according to the second invention is comprised of the following steps.

<Step-1>: (Li particle silica suspension preparation step) A step of preparing a suspension containing fine particle silica that is amorphous and has a weight average particle diameter of 10 μm or less.

<Step-2>: (Spherical granulated silica manufacturing process) Step-1
A step of granulating and drying the fine particle silica suspension obtained in step 1 by a spray drying method to obtain spherical granulated silica.

<Step-3>: (Spherical granulated silica sintering step) Step-2
A process of firing the spherical granulated silica obtained in step 1 and converting it into spherical silica having pores of controlled diameter and volume.

Each of the steps described above will be explained in sequence below.

[1] Particulate silica suspension preparation step (Step-1) When carrying out the method of the present invention, the impurity content in the raw material amorphous silica is not limited, but it may be Accordingly, it is preferable to use high-purity amorphous silica with a low impurity content.

In particular, when producing spherical silica used as a filler for encapsulants in high-density integrated circuit electronic components, the amorphous silica used as a raw material in the method of the present invention and the obtained spherical silica are: The content of alkali metal elements such as Na and K, alkaline earth metal elements such as Mg and Ca, and halogen elements is 1 ppm or less, and 1)U.

It is preferable that the content of each radioactive element such as Th is 1 ppb or less.

High purity amorphous silica with low impurity content is
For example, in JP-A-62-301 proposed by the present inventors,
No. 1 or JP-A No. 62-283809, a fine fibrous coagulum obtained by extruding an aqueous alkali metal silicate solution through pores into a water-miscible organic medium or an acid solution is acidified. It can be obtained by treating with a containing liquid and then washing with water to extract and remove impurities. Also,
In this case, alkoxides can also be used as raw materials.

In an embodiment when an alkali metal silicate aqueous solution is used as a raw material, an alkali metal silicate aqueous solution prepared in advance to have a viscosity in the range of 2 to 500 poise is mixed with a pore size of 0.
The gel is extruded into a coagulation bath consisting of a water-miscible organic medium or an acid solution through a nozzle in the range of 0.02 to 1 fi to coagulate it into a fibrous, columnar or granular form, and the resulting gel is treated with an acid-containing liquid and then washed with water. do.

By the above method, the f41. Fe.

High purity amorphous silica can be obtained in which the content of various impurities such as transition metal elements such as Ti is 1 ppm or less.

The water-miscible organic medium used in the coagulation bath is as follows:
For example, alcohols such as methanol, ethanol, and n-propanol, esters such as methyl acetate and ethyl acetate, ketones such as acetone 2-methyl ethyl ketone, and dimethyl acetamide.

Amides such as dimethylformamide, dimethyl sulfoxide, etc. can be mentioned.

In addition, the acid used in the coagulation bath is sulfuric acid.

Inorganic acids such as nitric acid and 9-hydrochloric acid can be mentioned, but it is particularly preferable to use sulfuric acid and nitric acid, and as the acid solution, an aqueous solution of these acids is practically preferable.

The acid concentration is in the range of 0.1 to 4N, preferably 0.5 to 3N, more preferably 1 to 2N.

The coagulation bath temperature is preferably maintained at 25°C or higher, preferably in the range of 40 to 80°C.

The purification of silica obtained by reacting an aqueous alkali metal silicate solution with an acid includes substances selected from mineral acids such as sulfuric acid dinitric acid and hydrochloric acid, peroxides such as hydrogen peroxide, and chelating agents. Known methods such as washing with an aqueous solution can be used.

The amorphous silica thus obtained is wet-pulverized to prepare a fine-particle silica suspension.

For wet milling, conventional equipment can be used, such as pot mills, tube mills, transfer ball mills such as conical ball mills or compartment mills, vibrating ball mills, or media agitation mills such as tower mills, stirred tank mills, etc. Preferably, a transfer ball mill or a vibratory ball mill is used.

In addition, the materials of the main parts of the crushing device that come into contact with the crushed material and the crushing media such as balls and rods used as necessary are usually made of alumina, zirconia, plastic-coated steel, silicon carbide, or silicon nitride. In addition, if mixing of aluminum, zirconium, etc. is undesirable, a suitable material may be selected from silicic materials such as quartz glass, fused silica, crystal, azure, or silica stone.

In addition, the size of the grinding medium made of a rigid body such as a ball, which may be used as necessary, is in the range of 0.5 to 25 mm in diameter;
Preferably it is in the range of 1 to 10 cranes. In particular, when it is desired to obtain ultrafine silica particles having an average particle diameter of 1 μm or less, the grinding media used preferably have a diameter in the range of 1 to 5 fi.

In the method of the present invention, water is used as a dispersion medium during wet grinding, and colloidal silica, carboxymethyl cellulose, etc. can also be added as a binder.

In addition, a liquid organic compound can be used as a dispersion medium, and specific examples of water-soluble liquid organic compounds include alcohols such as methanol and ethanol, amides such as formamide, dimethylformamide, and dimethylacetamide, acetone, and methyl ethyl ketone. Examples include ketones. Moreover, a mixture of water and a water-soluble organic compound can also be used as a dispersion medium.

When using an aqueous medium, the pH of the system during grinding is between 2 and 11.
, preferably 2 to 5 or 7 to 11. If the pH of the system during pulverization is less than 2, the acid content increases,
Further, when it exceeds 11, the solubility of silica in the medium increases, which is undesirable.Furthermore, when it exceeds 5 and is less than 7, the fluidity of the obtained silica suspension tends to decrease. p
In adjusting H, mineral acids such as sulfuric acid and hydrochloric acid can be used as acids, and amines such as ammonia and methylamine can be used as alkalis.

The amorphous silica to be wet-pulverized in this step is a slurry-like silica that has not been washed with water and separated from the washing water in the above treatment;
A wet product obtained by separating the washing water, a dry product obtained by drying using an appropriate method, or a dry product obtained by heating and firing using an appropriate method can be used. . These can be wet-pulverized individually or mixed in any proportion.

Note that by firing amorphous silica under appropriate conditions, the pore volume and silanol group concentration of the silica particles can be adjusted. In this case, the firing temperature of the raw material amorphous silica for grinding is preferably in the range of 500 to 1300°C, more preferably 800 to 1290°C. Since the increase in the viscosity of the silica suspension is relatively small, it is possible to increase the limit of the silica concentration in the fine-particle silica suspension that can be handled.

The conditions of the grinding process, such as the amount of raw silica and grinding media loaded into the grinding device, and the selection and combination of the diameters of the grinding media, are determined by the combination of raw silica, the average particle size of the target fine silica, and the amount of silica in the suspension. The silica concentration is selected appropriately depending on the silica concentration, etc., but the silica concentration in the fine particle silica suspension obtained by wet pulverization is usually 5 to 45% by weight when using silica without calcination treatment, and 5 to 45% by weight when silica without calcination treatment is used. When using silica, the amount varies depending on the conditions of the firing process, and is in the range of 30 to 80% by weight.

Here, the average particle diameter of the silica particles constituting the spherical granulated silica produced in Step-2 is an important factor governing the density and strength of the silica obtained by firing in the next Step-3. The smaller the average particle diameter of the silica particles to be sintered, the more dense the spherical silica obtained in step-3 becomes.

Therefore, the average particle size of the fine silica particles obtained by wet grinding in this step-1 must be 10 μm or less,
Preferably 5 μm or less, more preferably 0.3 to 1 μm
is within the range of When the average particle size exceeds 10 μm, the temperature required for the sintering process becomes too high, and sintering between particles progresses as well as within the particles, making it impossible to obtain the desired spherical silica.

Note that when ultrafine silica particles having an average particle size of 1 μm or less, such as Aerosil silica, are used as a raw material, it is not necessary to perform the above-mentioned wet pulverization treatment. In this case, raw silica may be dispersed in an aqueous medium to obtain a desired silica concentration.

[2] Spherical granulated silica manufacturing process (Step-2) In this step, the fine-particle silica suspension prepared in Step-1 is sprayed into a stream of hot air using a spray drying method, granulated into spherical shapes, and dried. to produce spherical granulated silica.

The relationship between the direction in which the fine particle silica suspension is sprayed and the direction in which the hot air flows during spray drying in the method of the present invention is as follows:
You can choose between parallel flow, countercurrent flow, and mixed flow. Moreover, hot air can also be supplied to the drying area in multiple stages.

Various mechanisms such as a centrifugal type, a pressure nozzle type, and a two-fluid nozzle type can be used to spray the particulate silica suspension.

In the method of the present invention, the particle size of the spherical granulated silica obtained by spray drying is preferably 0.1 fi or less. As a result, the particle size of the spherical silica obtained by firing in step-3 can be reduced to 0.1 or less, and the particle size is 1.
Spherical silica in the range of ~100 μm can be obtained.

The silica concentration in the fine particle silica suspension to be spray dried is in the range of 5 to 80% by weight, preferably 10 to 60% by weight, and the hot air temperature is 10 to 450°C, preferably 30 to 60%.
The temperature is preferably in the range of 250°C, and the pH of the fine particle silica suspension to be spray dried is preferably in the range of 2 to 11.

In addition, during spray drying, if the silica concentration in the particulate silica suspension is low and the hot air temperature is high, granulated silica may not be obtained in a spherical shape, and may become hollow or have large dents on the particle surface. . To prevent this, it is preferable to increase the silica concentration in the particulate silica suspension and lower the hot air temperature.

In addition, as a raw material for obtaining spherical granulated silica in this step, after wet-pulverizing the amorphous silica in various states individually in step-1, the resulting fine particle silica suspension is mixed in an appropriate ratio. The mixture can be used as a raw material for producing spherical granulated silica in this step.

[3] Spherical granulated silica firing step (Step-3) In this step, the spherical granulated silica obtained in Step-2 is fired to obtain the spherical silica targeted by the present invention.

The spherical granulated silica obtained by spray-drying the suspension of amorphous silica in an aqueous medium obtained in step-2 still contains a large amount of water and has many pores, and it cannot be pulverized by the pulverization process. Since the obtained particulate silica is only slightly aggregated with each other, it is not suitable as a filler for a sealant as it is.

Therefore, the purpose of the firing treatment in this step is: (1) to remove the residual moisture in the spherical granulated silica, and further reduce the existing silanol groups to about 0.1% by weight or less to make the silica particles hydrophobic; ■ It closes the pores of the silica particles that make up spherical granulated silica, changing the silica particles into a dense structure that is difficult for moisture to penetrate. .1μm
The purpose of the present invention is to obtain spherical silica having pores in the range of 0.02 to 0.15 sl/H and having the pore volume in the range of 0.02 to 0.15 sl/H.

Here, the firing is performed by heat treatment. In this case, the firing temperature that can achieve the objectives (1) and (2) above is 1000°C or higher, particularly preferably in the range of 1100 to 1300°C. If the heating temperature is less than 1000°C, it is insufficient to achieve the above objectives (1) and (2).

For example, the amorphous silica obtained by the method [1] above is heated to 8
In the silica obtained by firing at 00°C, silanol groups equivalent to 2% by weight remain (1250°C firing method),
In addition, the specific surface area is 500 ra''/g, and many pores still remain.When this silica was exposed to an atmosphere with a temperature of 20°C and a relative humidity of 70% for 3 days, it contained water equivalent to 3% by weight. absorbed.

Therefore, the firing conditions for obtaining spherical silica having pores with a diameter and volume in the above range are a temperature of 1000 to 1300°C, preferably 1100 to 1290°C, more preferably 120°C.
It is in the range of 0 to 1280°C. The firing time is in the range of 1 minute to 10 hours, preferably 30 minutes to 6 hours, and more preferably 1 to 5 hours. The combination of temperature and time as the firing conditions is appropriately selected depending on the particle size of the silica in the fine particle silica suspension before spray drying prepared in step-1. The smaller the average particle size of silica at this stage, the more the firing conditions for imparting the above-mentioned physical properties move toward lower temperatures and shorter times.

The atmosphere in which the firing process is performed is not particularly limited, and may include Ar,
An inert gas atmosphere such as He, an oxidizing atmosphere such as air, a reducing atmosphere such as hydrogen, a water vapor atmosphere, or a chlorine-containing atmosphere that can effectively remove impurities in silica can be used.

Moreover, the heating source is optional, and electric heat or combustion gas can be used from an economical point of view. In addition, plasma heating and an image furnace can also be used.

The spherical silica obtained as described above has pores with a diameter of 0.01 to 0.1 μm as described above, and a volume of the pores of 0.02 to 0.15 mI! /g, and the spherical silica obtained in the present invention is suitable as a filler for epoxy resin compositions, and when used in epoxy resin compositions for semiconductor encapsulation, it has a low expansion coefficient, high fluidity and An epoxy resin composition having the advantages of high strength and high reliability can be obtained.

Here, the epoxy resin composition for semiconductor encapsulation containing spherical silica as a filler of the present invention will be described in more detail. C).

In this case, the epoxy resin used in the present invention (al is not particularly limited as long as it has two or more epoxy groups in one molecule; for example, orthocresol novolank type epoxy resin, phenol novolak type epoxy resin, resin cyclic epoxy resin, bisphenol type epoxy resin, substituted or unsubstituted triphenol alkane type epoxy resin,
Examples include halides of the above-mentioned epoxy resins, and one or more of these may be appropriately selected and used.

In addition, the curing agent ('b) is selected depending on the epoxy resin, such as amine curing agents, acid anhydride curing agents, phenol novolak type curing agents, etc. Among them, phenol novolak type curing agents are used. This is more desirable in terms of moldability and moisture resistance of the composition. In addition, specific examples of the phenol novolac type curing agent include phenol novolak resin, cresol novolac resin, and the like.

Here, the amount of the curing agent is not particularly limited, but when using a phenol novolak type curing agent, the molar ratio of the epoxy group in the epoxy resin to the phenolic hydroxyl group in the curing agent is 0.5 to 1. A range of 5 is preferable.

Further, it is preferable to add a curing accelerator to the epoxy resin composition of the present invention in order to promote the reaction between the epoxy resin and the curing agent. As the curing accelerator, one or two types of imidazole compounds, undecene compounds such as 1,8-diazabicyclo(5,4,0)undecene-7 (DBU), phosphine compounds such as triphenylphosphine, and tertiary amines can be used. The above is used. Note that the amount of the curing accelerator used is not particularly limited, and may be a normal amount.

Furthermore, in the present invention, a silicone polymer can be blended for the purpose of reducing stress in the epoxy resin composition.
The addition of silicone-based polymers significantly reduces the occurrence of package cranking in thermal shock tests.

Here, silicone polymers include, for example, silicone oils, silicone resins, or silicone rubbers having epoxy groups, amino groups, carboxyl groups, hydroxyl groups, hydrosilyl groups, vinyl groups, etc., and furthermore, these silicone polymers and phenol novolak resins, epoxidized A copolymer with an organic polymer such as phenol novolafuku resin can be used.

The amount of the silicone polymer to be blended is preferably 1 to 50 parts based on 100 parts of the total amount of the epoxy resin and curing agent.

The spherical silica of the present invention used as a filler in such an epoxy resin composition has the above-mentioned specific pores, but also has an average particle size of 1 to 30 μm, particularly 5 to 15 μm.
Preferably it is μm. In addition, the specific surface area is 1 to 1O
+"/g, particularly 2 to 7+st/g, is preferably used.

The blending amount of the spherical silica is preferably 250 to 700 parts by weight, particularly 350 to 650 parts by weight, based on 100 parts by weight of the total amount of the epoxy resin and curing agent.

In addition to the above-mentioned spherical silica, other fillers such as crushed silica may be added to the epoxy resin composition as needed.

Various additives can be further added to the epoxy resin composition if necessary. For example, waxes, mold release agents such as fatty acids such as stearic acid and their metal salts, pigments such as carbon black, flame retardants, surface treatment agents (T-glycidoxypropyltrimethoxysilane, etc.), epoxysilane, Coupling agents such as vinyl silane, boromine compounds, alkyl titanates, anti-aging agents, and other additives.
A species or two or more species can be blended.

The above-mentioned epoxy resin composition is manufactured by uniformly stirring and mixing a predetermined amount of the above-mentioned components, heating the mixture to 70 to 95°C in advance, kneading it with a kneader, roll, extruder, etc., cooling it, and pulverizing it. It can be obtained by such methods. Here, there is no particular restriction on the order of blending the components.

The epoxy resin composition thus obtained can be effectively used for sealing semiconductor devices such as DIP type, flat punk type, PLCC type, SO type, etc. In this case, conventionally employed molding methods such as transfer molding, etc. This can be done by employing injection molding, casting methods, etc. In addition, the molding temperature of the epoxy resin composition is 150 to 180°C,
Post-curing is preferably performed at 150-180°C for 2-16 hours.

[Effects of the Invention] The spherical silica of the present invention hardly reduces the fluidity of the encapsulant even when the filling rate is increased, and increases the strength of the encapsulant, so it is suitable for use as an encapsulant for electronic components. It is suitably used as a filler.

Moreover, by the method of the present invention, the diameter is 0.01 to 0.1μ.
m, and the volume of these pores is 0.02 to 0.15 mm. It is possible to obtain spherical silica suitable as a filler for an encapsulant, which does not reduce the fluidity of the encapsulant even when the filling rate is increased and increases the strength of the encapsulant, which is in the range of /g. can.

Furthermore, by using the spherical silica of the present invention as a filler, it is possible to obtain an epoxy resin composition for semiconductor encapsulation that has a low coefficient of expansion and high strength without decreasing fluidity even when the filling rate is increased.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The invention is not limited to the following examples.

1-1) Production of amorphous silica JIS No. 3 water glass was heated and concentrated to have a viscosity of 300 cps at 20°C. Approximately 81 of this water glass was pressurized with a pump, passed through a filter (opening 70 μm), and passed through a nozzle (pore diameter Q, 2 m, number of holes 50) into a coagulation bath containing 8 wt% sulfuric acid aqueous solution 3001 maintained at 50°C. It was pushed out at a speed of 1 m/sec.

Freshly prepared 10 times the amount of silica obtained in fibrous form 8
The sample was immersed in a wt% aqueous sulfuric acid solution and stirred for about 1 hour at a temperature of about 95°C to extract impurities.

The obtained short fibrous silica was washed with pure water until the pH of the washing solution was 4.
After washing until
kg of amorphous wet silica was obtained.

This wet silica was dried using a hot air dryer at a temperature of 150° C. for 8 hours to obtain 3.7 kg of dry silica.

1-2) Preparation of fine particle silica suspension 1.0% of the dried silica obtained in step 2 of 1-1) above.
Place the pupil in a quartz glass ball (diameter 5
1n) 41 was placed in a quartz glass ball mill (inner volume: 1ON) and pulverized at 50 rpm+ for 24 hours to obtain a fine particle silica suspension (silica concentration = 30% by weight) with an average particle size of 1.0 μm. Ta.

1-3) Production and firing of spherical granulated silica 1-2)
The fine particle silica suspension (3 batches) obtained as above was granulated and dried using a spray dryer to obtain spherical granulated silica having a diameter of about 2.5 pupils.

The obtained spherical granulated silica was placed in a quartz crucible, and heat treated for 4 hours at a temperature of 1250°C using an electric furnace.2.
3 kg of spherical silica was obtained.

The obtained spherical silica has an average particle size of 15μ and a density of 2.
．． 2 g/am', measured by mercury porosimetry, 0,
The volume of pores with a diameter in the range of 0.01 to 0.1 μm is 0.01 μm.
03 mJ/g, and the surface was spherical with no depressions and had a smooth surface with few irregularities.

The impurity content of this spherical silica is NaO, 3ppm
810.4ppm, K is O,l ppm or less, U
was less than 0.05 ppb.

Spherical silica was obtained by changing the firing time of spherical granulated silica obtained in the same manner as in Example-1. The results are shown in Table 1, and it was found that the pore volume increased as the firing time was shortened.

, ratio 1 effect example - 2 upper (when the degree of firing is strengthened).

When the spherical granulated silica obtained in the same manner as in Example 1 was fired at a temperature of 1280°C for 4 hours, the pore volume was 0.0.
1a+l/g of silica was obtained.

, Comparison M-2I (when the degree of firing is relaxed).

On the other hand, when the spherical granulated silica obtained in the same manner as in Example-1 was fired at a temperature of 1200° C. for 2 hours, silica with a pore volume of 0.16 ml/g was obtained.

Tensuke Kanji 1 A fine particulate silica suspension (silica concentration: 30% by weight) obtained by pulverizing dry silica obtained in the same manner as in Example-1 and dry silica before pulverizing were heated at different temperatures. 1200℃
The calcined silica obtained by firing for 2 hours at Spherical granulated silica was obtained in the same manner as in Example-1.

Regarding the obtained spherical granulated silica, at a temperature of 1250 ° C.
Spherical silica was obtained by firing for 1 hour or 2 hours, respectively. The results are shown in Table 1.

Individual difference ±2 (The average particle size of the fine silica particles in the fine silica suspension is 0.
Prepare 3 μm or 0.5 μm, respectively.
Other conditions were the same as in Example-1 to obtain spherical granulated silica. When each was fired at a temperature of 1200°C for 4 hours, the pore volume was 0.03 or 0.04ml!
/g of spherical silica was obtained.

4-Suspension- Spherical silica particles were obtained in the same manner as in Example 1 except that fine particle silica suspensions having a silica concentration of 40% or 50% by weight were prepared respectively. The pore volume of the obtained spherical silica was 0.0 as in Example-1.
It was 03+wl/g.

Ohba ±25 fine particle silica (manufactured by Nippon Aerosil Co., Ltd., average particle size 0.05
μm+) was mixed with 12 ml of pure water to obtain a fine particle silica suspension (silica concentration: 20% by weight).

The thus obtained fine particle silica suspension was granulated and dried using a spray dryer to obtain about 2.5 kg of spherical granulated silica.

The obtained spherical granulated silica was placed in a quartz crucible and heat treated for 2 hours at a temperature of 1000°C using an electric furnace.
kg of spherical silica was obtained.

The obtained spherical silica has an average particle size of 12 μm and a density of 2
．． 2g/C! 13, and 0,0 as measured by mercury porosimetry
The volume of pores with diameters ranging from 1 to 0.1 μm is 0.0
It was 4*J/g, and had a spherical shape with no depressions and a smooth surface with few irregularities.

The impurity content of this spherical silica is Na 0.2pp
+111A I 0.3ppm, K is Ool p
pm or less, and U was 0.05 ppb or less.

A fine particle silica suspension (silica concentration: 20% by weight) was obtained from a silica sol (average particle size: 0.05 μm) obtained by hydrolyzing ethyl silicate in the liquid phase.

This fine particle silica suspension was granulated and dried using a spray dryer to obtain spherical granulated silica.

The obtained spherical granulated silica was placed in a quartz crucible and heat treated at 1000°C for 2°5 hours using an electric furnace.
Spherical silica was obtained.

The obtained spherical silica has an average particle size of 13 μm and a density of 2
．． 2 g/>” and 0,0 as measured by mercury porosimetry.
The volume of pores with diameters ranging from 1 to 0.1 μm is 0.0
It was 3 m#/g, and had a spherical shape with no depressions and a smooth surface with few irregularities.

The impurity content of this spherical silica is Na 0.2pp
s++Al10.1ppm, K is 0.1ppm
Hereinafter, U was 0.05 ppb or less.

Table 1 shows the properties of the spherical silica obtained by the above method.

Large m needle=, comparison, comparative side 1 Using silicas A to 0 obtained in Examples 1 to 7 and comparative examples 1 and 2, and the following silicas P and Q as comparative examples, the second
The epoxy resin compositions shown in the table were prepared and the following tests were conducted.

Silica P: Average particle size: 5μ noodles.

Specific surface area 1.5+ez/g Silica Q: average particle size 14 μm.

Specific surface area 3.2+n2/g Pore volume 0.01w i 7g.

spherical silica Pore volume 0.01ml 7g.

Crushed silica test 11''l (a) Spiral flow value Using a mold according to EMMI standard, 160℃, 70℃
It was measured under the condition of kg/cd.

(b) Bending strength: 160℃, 70kg according to JIS-K6911
A bending rod of 10×4×100n+ was molded at a /cd molding temperature of 3 minutes, post-cured at 180° C. for 4 hours, and then measured at 25° C. (bending strength ■).

In addition, the sample was post-cured at 180°C for 4 hours and left in a 121t presser car for 20 hours, and then measured at 215°C (bending strength ■).

(c) Expansion coefficient, glass transition temperature 50°C to 100°C when the temperature was raised from 25°C to 250°C at a rate of 5°C per minute using a daylight meter using a test piece of 4 cranes φ x 15 cranes. Measured from the straight line up to.

(d) Solder crack resistance after moisture absorption Package size: 14 x 20 x 2.31 m, molded at 175°C for 2 minutes and post-cured at 180°C for 4 hours;
85 flat packages with an island area of 8 x 10 m
After leaving it in a constant temperature and humidity chamber at ℃/85%RH for 24 hours,
When placed in a 15° C. solder bath, the number of package cranks generated was measured.

The above results are shown in Table 2.

From the above results, it is clear that the epoxy resin composition filled with spherical silica of the present invention has low fluidity, high bending strength, and excellent cracking and scratching resistance after moisture absorption and soldering. .

teenager Reason Man small island Takashi Tsukasa (1 other person)

Claims (1)

[Scope of Claims] 1. A pore having a diameter in the range of 0.01 to 0.1 μm, and a volume of the pore having a diameter in the range of 0.0 μm.
Spherical silica ranging from 2 to 0.15 ml/g. 2. The spherical silica according to claim 1, wherein the content of alkali metal elements, alkaline earth metal elements, halogen elements, and transition metal elements is each 1 ppm or less, and the content of radioactive elements is each 1 ppb or less. Spherical silica. 3 A suspension of amorphous silica having a weight average particle diameter of 10 μm or less is spray-dried to obtain spherical granulated silica, and then the spherical granulated silica is fired at a temperature in the range of 1000 to 1300°C to reduce the diameter has pores with a diameter in the range of 0.01 to 0.1 μm, and the volume of the pores with a diameter in the range is 0.
．． A method for producing spherical silica, characterized in that spherical silica is obtained in a range of 0.02 to 0.15 ml/g. 4. The content of alkali metal elements, alkaline earth metal elements, halogen elements, and transition metal elements in the amorphous silica is each 1 ppm or less, and the content of radioactive elements is each 1 ppb or less. The method for producing the described spherical silica. 5. An epoxy resin composition containing the spherical silica according to claim 1 as a filler. 6. A cured product obtained by curing the composition according to claim 5.