JP2006176791A - Material for sealing electronic part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material for sealing semiconductors, which has excellent flame retardancy, water resistance and thermal conductivity. <P>SOLUTION: The material for sealing electronic parts comprises magnesium hydroxide particles which are characterized by fulfilling following requirements (i)-(iv): (i) the average secondary particle diameter is 5 μm or less, as measured by the laser diffraction scattering method; (ii) the BET specific surface area is 10 m<SP>2</SP>/g or less; (iii) the total content of Fe and Mn compounds measured as metals is 0.02 wt.% or less; and (iv) the total content of U and Th compounds calculated as metals is 10 ppb or less. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor sealing material, and more particularly to a semiconductor sealing material used in a resin composition for semiconductor sealing excellent in flame retardancy, water resistance and thermal conductivity.

Semiconductor elements and integrated circuit elements are sealed with various sealing materials so as not to be affected by external vibration, impact, dust, moisture, atmospheric gas, and the like. As a sealing material, a metal material, ceramic, glass or the like has been used, but from the viewpoint of cost and mass productivity, most of them are currently sealed with resin using plastic.
Conventionally, epoxy resin, silicone resin, phenol resin, diallyl phthalate resin, polyimide resin and the like have been used, and satisfactory results have been achieved.

However, technological innovations in the semiconductor field have led to improvements in integration, miniaturization of device sizes, and miniaturization of wiring, and packages tend to be smaller and thinner. It has become necessary.
Further, as a sealing material, strength and thermal conductivity are required, and inorganic fillers have been blended.
Further, electronic parts such as semiconductor devices are required to have a high degree of flame retardancy, and a method of adding a bromine-based epoxy resin and antimony oxide has been performed. However, in this case, hydrogen bromide, bromine-based gas, antimony bromide, etc. generated during combustion are harmful to the human body and corrosive to equipment, and industrial waste and epoxy resin molding materials produced in the process of sealing semiconductor devices. In addition, environmental safety such as a problem of disposal of electronic parts using the molding material has been a problem.

Further, when the semiconductor device to which the flame retardant is added is left at a high temperature for a long time, the aluminum wiring on the semiconductor element is corroded due to the effect of the liberated bromine, causing a failure of the semiconductor device, resulting in a problem of reduced high-temperature reliability. In order to solve the above problems, a method of adding a metal hydroxide as a flame retardant has been proposed.
However, in this method, a large amount (40% by weight or more) of metal hydroxide must be blended, and the metal hydroxide that absorbs a large amount of water when the semiconductor device is exposed to a high temperature (usually 215 to 260 ° C.) absorbs moisture. Due to the rapid vaporization of moisture, problems such as swelling and cracking of the semiconductor device occur, and there is a problem that solder resistance decreases.

In addition, there is a problem that the function of the semiconductor element is deteriorated in a high temperature and high humidity environment of 80 to 200 ° C. and a relative humidity of 70 to 100%.
In order to solve this problem, Patent Document 1 discloses a composition in which a metal hydroxide is limited to magnesium hydroxide, a surface treatment is further applied to the magnesium hydroxide to prevent moisture absorption, and dispersibility in a resin is further improved. Proposed.
JP-A-9-176368

However, due to recent technological innovation in the semiconductor field, higher flame retardancy and higher moisture resistance and safety are required. Furthermore, if there are many impurities in the metal hydroxide particles, especially Fe compounds and Mn compounds, it will cause corrosion of molds and semiconductor elements, and with the recent increase in memory capacity, that is, higher integration of memory. If the content of radioactive materials such as uranium (U) and thorium (Th) is large due to a decrease in the amount of stored charge, the memory may generate a soft error due to alpha rays due to the decay of U, Th, etc. It has become a problem. For example, the content of U and Th is 1 ppb (ng / g) or less in a memory of 1 M to 4 M bits, and 0 in 4 to 16 M bits. Less than lppb (ng / g) is required to ensure reliability against soft errors. For this reason, it has been required that the content of the radioactive material of magnesium hydroxide blended in the synthetic resin used as the sealing material is very small.
It was also discovered that water-soluble alkali metal salts in magnesium hydroxide particles affect water resistance insulation.

Thus, according to the study by the present inventors, high purity magnesium hydroxide particles containing Fe compound, Mn compound, U compound and Th compound as impurities in a certain amount or less, and the average secondary particle size value is By blending a certain amount of magnesium hydroxide particles having a specific surface area (BET) value of 10 m ² / g or less and, if necessary, a certain amount of other inorganic fillers into the synthetic resin, Encapsulation of electronic components that has sufficient water resistance even under high humidity conditions, has corrosion resistance to molds and semiconductor elements, has excellent flame resistance and thermal conductivity, and suppresses soft memory errors It has been found that a resin composition and a resin composition for encapsulating electronic parts and a molded product thereof can be obtained.

  According to the study of the present inventors, the object of the present invention is to have a specific secondary particle diameter and a specific BET specific surface area as magnesium hydroxide particles to be blended in a synthetic resin, and also an Fe compound, Mn It has been found that this is achieved by selecting magnesium hydroxide particles in which the compound, U compound and Th compound are less than a certain amount, and more desirably, the content of the water-soluble alkali metal salt is extremely low.

That is, according to the present invention, there is provided an electronic component sealing material which is magnesium hydroxide particles satisfying the following requirements (i) to (iv).
(I) Average secondary particle size is 5 μm or less (ii) BET specific surface area is 10 m ² / g or less (iii) The total content of Fe compound and Mn compound is 0.02% by weight or less in terms of metal (Iv) The total content of U compound and Th compound is 10 ppb or less in terms of metal. Hereinafter, the present invention will be described in more detail.

  Magnesium hydroxide particles cause not only thermal conductivity but also a significant decrease in the thermal stability of the blended resin as the content of iron and manganese compounds in the magnesium hydroxide increases. However, the total amount of these compounds only satisfies the above range, and does not mean that the deterioration of the physical properties of the resin is not impaired, and the average secondary particle diameter and specific surface area must satisfy the above range, respectively. It is. As the average secondary particle diameter of the particles increases, the contact surface with the resin decreases and the thermal stability improves, but problems such as a decrease in mechanical strength and poor appearance occur. Therefore, the range of the average secondary particle diameter of magnesium hydroxide is 5 μm or less, preferably 3 μm or less.

The specific surface area of the magnesium hydroxide particles by the BET method is 10 m ² / g or less, preferably 5 m ² / g or less. Further, the total content of U compound and Th compound must be 10 ppb or less, preferably 5 ppb or less, more preferably 1 ppb or less in terms of metal. Desirably, the water-soluble alkali metal salt content is 0.05% by weight or less, preferably 0.03% by weight or less, and more preferably 0.003% by weight or less.

When the Fe compound and Mn compound content exceeds the above range, the thermal deterioration of the resin is affected. Furthermore, if the contents of the U compound and the Th compound are within the above ranges, the occurrence of soft errors in the memory can be reduced, but the soft errors increase as the contents increase.
As described above, the magnesium hydroxide particles have an average secondary particle diameter, a specific surface area, a total content of iron compound and manganese compound, a content of U compound and Th compound, and more preferably a content of water-soluble alkali metal salt. If it is within the range, a resin composition satisfying various properties such as compatibility with the resin, dispersibility, molding and processability, appearance of molded products, mechanical strength and flame retardancy, and reduction of memory soft errors can be obtained. It is done.

As long as the said magnesium hydroxide particle in this invention satisfies the requirements of said (i), (ii), (iii) and (iv), the adjustment method does not receive a restriction | limiting in particular.
The magnesium hydroxide particles satisfying the average secondary particle diameter of (i) and the specific surface area of (ii) are obtained by basically adopting the method and conditions described in, for example, JP-A No. 52-115799. Can be manufactured. That is, by using magnesium chloride or magnesium nitrate and an alkali substance such as alkali metal hydroxide, ammonia or magnesium oxide as raw materials, and heating them in an aqueous medium under pressure (preferably 5 to 30 kg / cm ² ). Can be manufactured.
At that time, by selecting impurities that do not contain impurities, particularly iron compounds and manganese compounds (and other metal compounds if necessary), U compounds and Th compounds, etc. Magnesium hydroxide particles satisfying the requirements (iii) and (iv) can be obtained.

If necessary, it is preferable to subject the magnesium chloride or magnesium nitrate as a raw material and the alkaline substance to a purification treatment in order to reduce the content of the impurities therein.
By washing the obtained magnesium hydroxide particles with ion exchange water or industrial water, the water-soluble alkali metal salt can be removed.
As a result of research conducted by the present inventors on the method for removing U and Th, it is appropriate that U in the magnesium hydroxide raw material is adsorbed and removed by hydrotalcite represented by the following formula (1). I understand.

（式中Ｍ^３＋はＡ１^３＋およびＦｅ^３＋の少なくとも１種、
ｘは０．２≦ｘ＜０．５の正数、
Ａ^２−はＣＯ_３ ^２−およびＳＯ_４ ^２−の少なくとも１種、
ｍは０〜２の数を示す。）
このハイドロタルサイトは天然品でも合成品でもよく、さらに好ましくはこれを水酸化マグネシウム原料に添加し、Ｕを除去する。水酸化マグネシウムの原料であるマグネシウム源と、アルミニウム源でハイドロタルサイトを合成し、濾過し、この濾液である塩化マグネシウムを水酸化マグネシウムの原料としても、合成されたハイドロタルサイトがＵを吸着しているので、Ｕの少ない塩化マグネシウムが得られる。
一例を示すと下記の通りである。

( ^Wherein M ³⁺ is at least one of A1 ³⁺ and Fe ³⁺ ,
x is a positive number of 0.2 ≦ x <0.5,
A ^2- is at least one of CO ₃ ^2- and SO ₄ ^2- ;
m shows the number of 0-2. )
This hydrotalcite may be a natural product or a synthetic product, and more preferably, this is added to the magnesium hydroxide raw material to remove U. Hydrotalcite is synthesized with magnesium source, which is the raw material of magnesium hydroxide, and aluminum source and filtered. Even if magnesium chloride, which is the filtrate, is used as the raw material of magnesium hydroxide, the synthesized hydrotalcite adsorbs U. Therefore, magnesium chloride with less U can be obtained.
An example is as follows.

Put ₂ L of bitter juice (MgC12 = 1.9 mo1 / L) in a 3 L beaker (U content is 126 ppb), add 2 mL of hydrochloric acid (manufactured by Wako Pure Chemical Industries, Ltd. KK) adjusted to a concentration of 5 N under stirring conditions, The mixture was stirred at room temperature (25 ° C.) for 30 minutes to obtain a bitter juice with pH = 1.6. While stirring the bitter juice, 20 mL of an aqueous solution of aluminum nitrate (manufactured by Wako Pure Chemical Industries, Ltd. KK) adjusted to a concentration of 54 g / L is added, and further, 23 mL of aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd. KK) adjusted to 14 wt% is being stirred. Then, the mixture was stirred at room temperature (25 ° C.) for 30 minutes to obtain a bitter juice having a pH of 6.5.
This bitter juice is a suspension containing a double hydroxide in which aluminum ions and some magnesium ions are co-precipitated. This was subjected to suction filtration with a Buchner funnel to obtain a bitter juice of magnesium chloride (MgCl ₂ ) = 1.7 mo1 / L as a filtrate.

The U content was 0.8 ng / mL or less.
This magnesium chloride was used as a Mg source and an alkali source was used as calcium hydroxide to obtain magnesium hydroxide. The magnesium hydroxide had a U content of 2 ppb.
This was compared with the U content of magnesium hydroxide obtained by reacting magnesium chloride with calcium hydroxide without U removal.

Although the mechanism of uranium removal is not clear, crystal growth of magnesium hydroxide occurs, the BET specific surface area is reduced, the dispersibility of the particles is improved, and powder properties suitable as an additive for resin are imparted.
The magnesium hydroxide particles used in the present invention are at least one surface treatment agent selected from the group consisting of higher fatty acids, anionic surfactants, phosphate esters, coupling agents and fatty acid esters of polyhydric alcohols. It may be surface treated.

  Examples of those preferably used as the surface treating agent are as follows. Higher fatty acids having 10 or more carbon atoms such as stearic acid, erucic acid, palmitic acid, lauric acid and behenic acid, alkali metal salts of the higher fatty acids, sulfate esters of higher alcohols such as stearyl alcohol and oleyl alcohol; polyethylene glycol Ether sulfate salt, amide bond sulfate ester, ester bond sulfate ester, ester bond sulfonate, amide bond sulfonate, ether bond sulfonate, ether bond alkyl aryl sulfonate, ester bond alkyl aryl sulfonate, Anionic surfactants such as amide-bonded alkyl aryl sulfonates; mono- or diesters such as orthophosphoric acid and oleyl alcohol, stearyl alcohol or a mixture thereof, and their acid forms or alkali metals Or phosphoric esters such as amine salts; γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β -(N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane / hydrochloride, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyl Triacetoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, γ- Chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (βmethoxyethoxy) silane, β- (3,4 epoxy cyclohexyl) ) Ethyltrimethoxysilane, γ-glycidoxypropylmethylethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyl Triethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-βaminoethyl) γ-aminopropyltrimethoxysilane, N-β Aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ Silane coupling agents such as methacryloxypropyltrimethoxysilane; isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, isopropyl tridecylbenzenesulfonyl titanate , Tetraoctyl bis (ditridecyl phosphite) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, isopropyl tridodecylben Zensulfonyl titanate, tetraisopropylbis (dioctylphosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis- (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyltriocta Titanate coupling agents such as noyl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, dicumyl phenyl oxyacetate titanate, diisostearoyl ethylene titanate Class: Aluminum couplings such as acetoalkoxyaluminum diisopropylate Agents, triphenyl phosphite, diphenyl tridecyl phosphite, phenyl ditridecyl phosphite, phenyl isodecyl phosphite, tri nonyl phenyl phosphite, 4,4′-butylidene-bis (3-methyl- 6-t-butylphenyl) -ditridecyl phosphite, trilauryl thiophosphite, etc., polyhydric alcohols such as glycerol monostearate, glycerol monooleate and fatty acids.

The surface treatment method of the magnesium hydroxide particles with the surface treatment agent can be carried out by a known wet or dry method. For example, as a wet method, the surface treatment agent may be added in a liquid or emulsion form to a slurry of magnesium hydroxide particles and mechanically mixed sufficiently at a temperature up to about 100 ° C.
As a dry method, the surface treatment agent may be added in a liquid, emulsion, or solid form with sufficient stirring with a mixer such as a Henschel mixer, and mixed sufficiently under heating or non-heating. Although the addition amount of a surface treating agent can be selected suitably, it is 0.01-10.00 weight% with respect to magnesium hydroxide particle, Preferably, it is 0.05-5.00 weight%.

The surface-treated magnesium hydroxide particles can be made into a final product form by appropriately selecting and implementing means such as water washing, dehydration, granulation, drying, pulverization, and classification, if necessary.
The surface treatment agent can also be added at the time of kneading the synthetic resin and the magnesium hydroxide particles. In the resin composition of the present invention, the proportion of the synthetic resin and magnesium hydroxide particles is 5 to 500 parts by weight, preferably 50 to 300 parts by weight, based on 100 parts by weight of the synthetic resin. It is.

  Moreover, (C) inorganic filler can be mix | blended as needed. The inorganic filler is blended for the purpose of improving strength and reducing hygroscopicity. In the present invention, when (C) an inorganic filler is blended, examples thereof include amorphous silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, silicon nitride, magnesium aluminum oxide, zirconia, zircon, Examples include clay, talc, calcium silicate, titanium oxide, antimony oxide, asbestos, glass fiber, calcium sulfate, and aluminum nitride, and any shape such as spherical, crushed, and fibrous can be used. Preferable specific examples of the inorganic filler are amorphous silica, crystalline silica, and alumina. In this case, the total amount of the inorganic filler including magnesium hydroxide particles is the total amount of the inorganic filler including the magnesium hydroxide particles. 60 to 95% by weight, preferably 70 to 90% by weight. Since the total blending amount is large, it is required to have good moldability, that is, good flowability and low viscosity.

  Examples of the synthetic resin include epoxy resin, silicone resin, phenol resin, diallyl phthalate resin, polyimide resin, polyphenylene sulfide resin, acrylic rubber, butyl rubber, ethylene propylene rubber, olefin elastomer, or fluororesin.

  The epoxy resin in the present invention is not particularly limited, and specific examples thereof include 4,4′-bis (2,3-epoxypropoxy) biphenyl and 4,4′-bis (2,3-epoxypropoxy) 3. , 3′5,5′-tetramethylbiphenyl, 4,4′-bis (2,3-epoxypropoxy) -3,3′5,5′-tetraethylbiphenyl, 4,4′-bis (2,3- (Epoxypropoxy) -3,3′5,5′-tetramethyl-2-chlorobiphenyl, biphenyl type epoxy resins having a biphenyl skeleton, 1,5-di (2,3-epoxypropoxy) naphthalene, 1,6- Naphthalene type epoxy resin such as di (2,3-epoxypropoxy) naphthalene, 4,4′-bis (2,3-epoxypropoxy) stilbene, 4,4′-bis (2, -Epoxypropoxy) Novolak type epoxy resins such as stilbene type epoxy resins such as -3,3'5,5'-tetramethylstilbene, cresol novolak type epoxy resins, phenol novolak type epoxy resins, and bisphenol A skeleton-containing novolak type epoxy resins. And aryl aralkyl type epoxy resins such as phenol aralkyl type epoxy resins and naphthol aralkyl type epoxy resins, dicyclopentadiene skeleton-containing epoxy resins, and polyfunctional epoxy resins such as tris (2,3′-epoxypropoxy) phenylmethane. . Among these, bifunctional epoxy resins such as biphenyl type epoxy resins, naphthalene type epoxy resins, and stilbene type epoxy resins are particularly preferably used. These may be used alone or in combination of two or more.

  Specific examples of the silicone resin include compositions containing polyorganosiloxane and a curing agent. This polyorganosiloxane composition is obtained by uniformly dispersing (a) a polyorganosiloxane base polymer, (b) a curing agent, and various additives as required. Of the various components used in such a composition, (a) the polyorganosiloxane base polymer and (b) the curing agent are appropriately selected according to the reaction mechanism for obtaining a rubber elastic body. As the reaction mechanism, (1) a crosslinking method using an organic acid oxide granule, (2) a method using a condensation reaction, (3) a method using an addition reaction, etc. are known. It is well known that the preferred combination of component (b), i.e., curing catalyst or crosslinking agent, is determined.

  The organic acid in the polyorganosiloxane as the base polymer of the component (a) used in such various reaction mechanisms is a monovalent substituted or unsubstituted monovalent hydrogen group, methyl group, ethyl group, propyl group, An unsubstituted hydrocarbon group such as an alkyl group such as a butyl group, a hexyl group or a dodecyl group, an aryl group such as a phenyl group, an aralkyl group such as a β-phenylethyl group or a βphenylpropyl group, or a chloromethyl group And a substituted hydrocarbon group such as 3,3,3-trifluoropropyl group. Of the silicone resins, silicone rubber is preferred.

  The curing agent is not particularly limited as long as it functions as a curing agent. For example, there are phenolic compounds, acid anhydrides, amine compounds, etc. Among them, phenolic compounds are preferable. Examples of phenolic compounds include phenols such as phenol, cresol, xylenol, hydroquinone, resorcin, catechol, bisphenol A, bisphenol F, or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene, and formaldehyde, acetaldehyde, propion. Resins obtained by condensation or cocondensation with aldehydes such as aldehyde, benzaldehyde, salicylaldehyde, etc. in the presence of an acidic catalyst, polyparavinylphenol resins, phenol aralkyl resins having xylylene groups synthesized from phenols and dimethoxyparaxylene And naphthol resins having a xylylene skeleton, and may be used alone or in combination of two or more.

  Examples of the curing accelerator include diazabicycloalkenes and derivatives thereof such as 1,8-diazabicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris ( Tertiary amines such as (dimethylaminomethyl) phenol, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, tributylphosphine, methyldiphenylphosphine, triphenyl Organic phosphines such as phosphine, tetra-substituted phosphonium / tetra-substituted borate such as tetraphenyl phosphonium / tetra-fail borate, 2-ethyl-4-methylimidazole / tetraphenyl borate DOO, and the like tetraphenyl boron salts such as N- methylmorpholine-tetra phenylalanine borate.

  In the resin composition of the present invention, if necessary, a release agent such as a curing agent natural wax, synthetic wax, higher fatty acid and its metal salt, or paraffin; colorant such as carbon black, pigment, foaming agent, plasticizer Agents, fillers, acid acceptors, reinforcing agents, antioxidants, UV absorbers, antistatic agents, lubricants, stabilizers, curing accelerators, and the like may be added. Moreover, you may add flame retardants, such as an antimony trioxide, a phosphorus compound, and a brominated epoxy resin.

  In order to reduce the stress, various elastomers may be added or reacted in advance. Specific examples include additive or reactive elastomers such as polybutadiene, butadiene-acrylonitrile copolymer, silicone rubber, and silicone oil. The resin composition for semiconductor encapsulation of the present invention is preferably mixed by melting and kneading each component, for example, melt kneading using a known kneading method such as a kneader, a roll single screw or biaxial extruder or a kneader. It is manufactured by doing.

  The semiconductor sealing material of the present invention is usually used for semiconductor sealing in a powder or tablet state. A low-pressure transfer molding method is generally used as a method for molding a member having a semiconductor fixed on a substrate with a semiconductor sealing resin composition, and an injection molding method or a compression molding method is also possible. As molding conditions, for example, a sealing resin composition is molded by molding at a molding temperature of 150 to 200 ° C., a pressure of 5 to 15 MPa, a molding time of 30 to 300 seconds, and a cured product of the sealing resin composition is sealed. The formed semiconductor molded product is manufactured. Moreover, you may heat-process the said molded object at 100-200 degreeC for 2 to 15 hours as needed.

  The curing agent used for curing the resin composition of the present invention is arbitrary as long as it is a compound that reacts with the resin, but when it is a cured product, a phenol compound having a hydroxyl group in the molecule as a compound having a low water absorption rate. Preferably used. Specific examples of the phenol compound include phenol novolak resin, cresol novolak resin, naphthol novolak resin, tris (hydroxyphenyl) methane, 1,1,2-tris (hydroxyphenyl) ethane, 1,1,3-tris (hydroxyphenyl). ) Propane, terpene and phenol condensation compounds, dicyclopentadiene-modified phenol resin, phenol aralkyl resin, naphthol aralkyl resin, catechol, resorcin, hydroquinone, virogallol, phloroglucinol and the like. Among them, a curing agent having a hydroxyl group equivalent of 130 or more is particularly preferable, and a phenol aralkyl resin or a terpene skeleton-containing phenol resin is particularly preferably used. The compounding quantity of a hardening | curing agent is 50-200 weight part with respect to 100 weight part of synthetic resins, Preferably it is 70-150 weight part.

In Examples, “%” and “part” mean “% by weight” and “part by weight” unless otherwise specified. In the examples, the characteristics of the magnesium hydroxide particles and the physical properties of the molded products were measured by the following methods. Molding was performed by transfer molding.
(1) Average secondary particle diameter of magnesium hydroxide particles The measurement is determined using a MICROTRAC particle size analyzer SPA type [manufactured by LEEDS & NORTHRUP INSTRUMENTS].

700 mg of the sample powder was added to 70 mL of water, and after 3 minutes of dispersion treatment with ultrasonic waves (manufactured by NISSEI, MODEL US-300, current 300 μA), 2-4 mL of the dispersion was taken and 250 mL of degassed water The particle size distribution is measured after the suspension is circulated for 8 minutes by operating the analyzer. The measurement is performed twice in total, and the arithmetic average value of the 50% cumulative secondary particle diameter obtained for each measurement is calculated to obtain the average secondary particle diameter of the sample.
(2) BET specific surface area of magnesium hydroxide particles Measured by an adsorption method of liquid nitrogen.
(3) U and Th
It was measured by ICP-MS (Inductivity Coupled Plasma-Mass Spectrometry) or atomic absorption method.
(4) Water-soluble alkali metal salt Atomic absorption (5) Heavy metal Measured by ICP mass spectrometry.
(6) Flame retardancy Measured according to UL94VE method.
(7) Thermal conductivity It measured by the probe method using the QTM quick thermal conductivity meter by Kyoto Electronics Industry Co., Ltd.
(8) Thermal stability Device: Tabai Espec Gear Oven GPHH-100
Setting conditions: 150 ° C, damper opening 50%
Set two test pieces as a set, sandwich the upper part with paper, hold it with a metal clip, hang it on a rotating ring, and pull it out over time.
Test piece: 1/12 inch Judgment: The time until whitening was observed on the test piece was used as a measure of thermal deterioration.
(9) Test of water resistance insulation of molded product A synthetic resin is a square of 10 cm on each side cut with scissors, and a test piece made of a rectangular parallelepiped with a thickness of 2 mm is placed in 95 ° C. ion exchange water for 48 hours. After dipping, it was taken out and the surface moisture was wiped off with a paper towel. Conditioning at 23 ° C. ± 2 ° C. and 50% RH was performed for 15 minutes. Under the same condition control, the volume resistivity was measured using Takeda Riken Kogyo's TR8401 and the water resistance of the test piece was obtained. However, the EVA test piece was immersed in ion exchange water at 70 ° C. for 168 hours.

Table 2 shows the properties of magnesium hydroxide used in the examples. However, in Examples 2 and 3, the magnesium hydroxide of Example 1 was surface-treated.
Each component shown in Table 3 was dry blended with a mixer at the composition ratio shown in Table 3. This was heated and kneaded for 5 minutes using a mixing roll having a roll surface temperature of 90 ° C., then cooled and crushed to produce a test piece of an epoxy resin composition.
Using this test piece, the thermal conductivity, flame retardancy, and thermal stability were measured by the methods described above. The results are shown in Table 3.
The type of the surface treatment agent for the magnesium hydroxide particles used was as follows, and the surface treatment agent was 2% by weight based on the magnesium hydroxide.

Example 1 None Example 2 Stearic acid Example 3 Epoxysilane coupling agent Example 4 None Example 5 None Example 6 is the same magnesium hydroxide particles as Example 1 Example 7 is the same magnesium hydroxide as Example 2 Particle Example 8 was the same magnesium hydroxide particle as Example 3. Example 9 was the same magnesium hydroxide particle as Example 1. Example 10 was the same magnesium hydroxide particle as Example 3.

Claims (13)

An electronic component sealing material, which is magnesium hydroxide, satisfying the following requirements (i) to (iv):
(I) Average secondary particle diameter measured by laser diffraction scattering method is 5 μm or less (ii) BET method specific surface area is 10 m ² / g or less (iii) Total content of Fe compound and Mn compound is converted to metal 0.02 wt% or less (iv) The total content of U compound and Th compound is 10 ppb or less in terms of metal 2. The electronic component sealing material according to claim 1, wherein the magnesium hydroxide particles have an average secondary particle diameter of 5 μm or less as measured by a laser diffraction scattering method. ^2. The electronic component sealing material according to claim 1, wherein the magnesium hydroxide particles have a specific surface area of 5 m ² / g or less by a BET method. 2. The electronic component sealing material according to claim 1, wherein the magnesium hydroxide particles have a total content of iron compound and manganese compound of 0.01 wt% or less in terms of metal. 2. The magnesium hydroxide particle has a total content of iron compound, manganese compound, cobalt compound, chromium compound, copper compound, vanadium compound, and nickel compound of 0.02% by weight or less in terms of metal. Material for sealing electronic parts. 2. The electronic component sealing material according to claim 1, wherein the magnesium hydroxide particles have a total content of U compound and Th compound of 5 ppb or less in terms of metal. 2. The electronic component sealing material according to claim 1, wherein the magnesium hydroxide particles have a total content of U compound and Th compound of 1 ppb or less in terms of metal. 2. The electronic component sealing material according to claim 1, wherein the total content of the water-soluble alkali metal compound in the magnesium hydroxide particles is 0.05% by weight or less in terms of alkali metal. 2. The electronic component sealing material according to claim 1, wherein the total content of the water-soluble alkali metal compound in the magnesium hydroxide particles is 0.03% by weight or less in terms of alkali metal. 2. The electronic component sealing material according to claim 1, wherein the total content of the water-soluble alkali metal compound is 0.003% by weight or less in terms of alkali metal. Use of the electronic component sealing material according to claim 1 for a synthetic resin. The use according to claim 11, wherein the synthetic resin is an epoxy resin, a silicone resin, a phenol resin, a diallyl phthalate resin, a polyimide resin, a polymaleimide resin or an unsaturated polyester. The use according to claim 11, wherein the synthetic resin is an epoxy resin.