JP2012092172A - Composition for sealing optical semiconductor, and light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for sealing an optical semiconductor which can form a sealing material having excellent heat resistance or the like and further having excellent moisture permeability resistance.SOLUTION: The composition for sealing the optical semiconductor comprises 40 to 95 mass% of polysiloxane (A) having an epoxy group and having a repeated structural unit represented by formula (1) (wherein, Ar denotes an aryl group). The light-emitting element obtained by sealing an optical semiconductor with the composition for sealing the optical semiconductor has no deterioration in an optical semiconductor by water vapor passed through a sealing material, and can be stably used over a long period of time.

Description

  The present invention relates to an optical semiconductor sealing composition, and more particularly to an optical semiconductor sealing composition capable of obtaining a sealing material having high heat resistance and high permeability resistance.

One important material that supports the performance of a light emitting diode (LED) is a sealing material that seals and protects the LED so that the performance of the LED does not deteriorate.
Conventionally, epoxy resin has been mainly used as a sealing material for a light emitting diode (LED) element. However, the epoxy resin has low heat resistance and light resistance. Therefore, in place of the epoxy resin, an LED sealing material mainly composed of polysiloxane having excellent heat resistance, light resistance and transparency is being developed.

  In Patent Document 1, a composition containing a polysiloxane obtained by reacting an epoxy group-containing alkoxysilane with a hydroxy-terminated polydimethylsiloxane causes peeling from a package substrate even under high-temperature conditions such as a solder reflow process. It is disclosed to provide a sealing material that does not.

  In Patent Document 2, a composition containing an epoxy group-containing organosiloxane compound having a specific structure and a 5-membered or 6-membered acid anhydride is excellent in heat resistance, light resistance, and transparency, such as a solder reflow process. It is disclosed to provide a sealing material that does not peel off from a package base material even under high temperature conditions and is unlikely to cause yellowing.

  In Patent Document 3, a composition containing a linear diorganopolysiloxane having an aliphatic unsaturated group at both ends of a molecular chain, an organosilicon compound, and a hydrosilylation catalyst has high transparency and refractive properties, and has strength characteristics. Provides a good sealing material.

  Patent Document 4 discloses a branched and / or three-dimensional network structure alkenyl group-containing organopolysiloxane having a high phenyl group content and a high hydroxyl group content, an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom, A composition containing an addition reaction catalyst and an organohydrogenpolysiloxane containing an epoxy group and / or an alkoxy group has high hardness and transparency, excellent heat resistance and light resistance, temperature dependency and It is disclosed to provide a sealing material having transparency without dependence on thermal history.

  Patent Document 5 discloses an organopolysiloxane having at least two alkenyl groups in one molecule, an organohydrogenpolysiloxane having at least two hydrogen atom-bonded hydrogen atoms in one molecule, and a catalyst for hydrosilylation reaction. It has been disclosed that the composition containing the composition provides a sealing material with little discoloration or lowering of luminance due to peeling from the optical semiconductor element even when used for a long time.

  However, these polysiloxane-based encapsulants are excellent in heat resistance and light resistance, but are inferior in moisture permeability due to the fact that cracks and voids are likely to occur due to shrinkage during sealing. . For this reason, in the light emitting element using the sealing material which has these polysiloxanes as a main component, there existed a problem that an optical semiconductor deteriorated with the water vapor which permeate | transmitted the sealing material.

JP 2010-13619 A JP 2010-111181 A JP 2010-132895 A JP 2007-246894 A JP 2006-093354 A

  An object of this invention is to provide the composition for optical semiconductor sealing which is excellent in heat resistance etc. and can form the sealing material excellent in moisture permeability.

  As a result of intensive studies to achieve the above object, the present inventor has found a composition containing a polysiloxane having an epoxy group and a structure in which one silicon atom in the siloxane skeleton is bonded to two aryl groups. When used, it was found that a sealing material having excellent heat resistance and moisture permeability was obtained, and the present invention was completed.

  That is, this invention is an optical semiconductor sealing composition characterized by containing 40-95 mass% of polysiloxane (A) which has an epoxy group and has a repeating structural unit shown to following formula (1). is there.

（式（１）中、Ａｒはアリール基を示す。）
前記光半導体封止用組成物においては、
前記ポリシロキサン（Ａ）中に含まれる前記式（１）に示す繰り返し構造単位の含有割合が、２０〜８０質量％であることが好ましく、
前記ポリシロキサン（Ａ）のエポキシ当量が１００〜１００００ｇ／ｅｑ．であることが好ましい。

(In the formula (1), Ar represents an aryl group.)
In the optical semiconductor sealing composition,
The content ratio of the repeating structural unit represented by the formula (1) contained in the polysiloxane (A) is preferably 20 to 80% by mass,
The epoxy equivalent of the polysiloxane (A) is 100 to 10,000 g / eq. It is preferable that

Moreover, it is preferable that the composition for optical semiconductor sealing contains the said hardening | curing agent for epoxy resins (B) further,
The epoxy resin curing agent (B) is preferably an acid anhydride.

  Another invention is a light emitting device formed by sealing an optical semiconductor using the optical semiconductor sealing composition.

  The encapsulant obtained by curing the composition for optical semiconductor encapsulation of the present invention is excellent in heat resistance and the like, and is excellent in moisture permeability resistance. For this reason, the light-emitting element obtained by encapsulating the optical semiconductor with the composition for encapsulating an optical semiconductor of the present invention can be used stably over a long period without deterioration of the optical semiconductor due to water vapor that passes through the encapsulant. can do.

FIG. 1 is a schematic view showing a specific example of a light-emitting element obtained by encapsulating an LED with the composition for encapsulating an optical semiconductor of the present invention.

The composition for optical semiconductor encapsulation of the present invention contains a resin component such as polysiloxane as a main component, and is usually used in a state containing a curing agent component for curing the resin component.
In order to suppress discoloration of the sealing material due to the heat treatment for sealing, and to suppress the precipitation of the phosphor due to the heat treatment when the phosphor is used, the optical semiconductor sealing composition is usually as much as possible. A device for heat treatment under mild conditions, for example, a device for shortening the heat treatment time as much as possible is made. As one of the devices, a highly reactive curing agent is usually used.

It is easily conceived that such a composition containing a highly reactive curing agent and a resin component has poor storage stability.
For this reason, a composition containing a resin component and a curing agent are usually prepared separately, and these are mixed and used immediately before sealing.

  Therefore, in the composition for optical semiconductor encapsulation of the present invention, it may be prepared as a resin composition containing a curing agent, but it is prepared as a resin composition not containing a curing agent and cured at the time of use. It is preferable to mix an agent into the composition.

<Composition for optical semiconductor sealing>
The composition for optical semiconductor sealing of this invention contains 40-95 mass% of polysiloxane (A) which has an epoxy group and has a repeating structural unit shown to following formula (1).

（式（１）中、Ａｒはアリール基を示す。）

(In the formula (1), Ar represents an aryl group.)

Polysiloxane (A)
The polysiloxane (A) has a repeating structural unit (hereinafter also referred to as a specific structural unit) represented by the above formula (1). In formula (1), Ar represents an aryl group.

When the polysiloxane (A) has the repeating structural unit represented by the above formula (1), the sealing material obtained by curing the composition for optical semiconductor sealing of the present invention is excellent in moisture permeability resistance.
The reason why a sealing material excellent in moisture permeability can be obtained when the polysiloxane (A) has the repeating structural unit represented by the above formula (1) is not clear, but the polysiloxane (A) present in the sealing material This is considered to be because the aryl group can easily block the permeation of water vapor in the encapsulant because the aryl group in the structure easily stacks.

  Examples of the aryl group represented by Ar in the formula (1) include aromatic hydrocarbon groups such as phenyl groups and naphthyl groups, and groups containing heteroatoms (O, S, N) such as isocyanur groups. . Among these, an aromatic hydrocarbon group such as a phenyl group or a naphthyl group is preferable in that it has high heat resistance without being colored in the visible light region. Two Ar in the formula (1) may be the same or different aryl groups.

  The content ratio of the repeating structural unit represented by the formula (1) contained in the polysiloxane (A) is preferably 20 to 80% by mass, more preferably 25 to 70% by mass, and further preferably 30 to 60% by mass. is there. If the content is less than 20% by mass, moisture permeability may be deteriorated. If the content is more than 80% by mass, a film having sufficient mechanical strength may not be formed.

  Polysiloxane (A) has an epoxy group. In the composition for optical semiconductor encapsulation of the present invention, cross-linking between molecules occurs by ring-opening polymerization of the epoxy group of polysiloxane (A), and the composition for optical semiconductor encapsulation is cured.

  The epoxy equivalent of polysiloxane (A) is preferably 100 to 5000 g / eq. More preferably, 300 to 3000 g / eq. It is. The epoxy equivalent is 100 g / eq. Less than 5000 g / eq., Resulting in a decrease in the transparency of the cured film. If it exceeds, curing failure tends to occur.

  The polysiloxane (A) preferably has at least one group represented by the following general formulas (2) to (5) as a group containing an epoxy group. When the polysiloxane (A) has such a group, a thick film can be formed on the mm order of the cured product.

〔一般式（２）中Ｒ⁵はメチレン基または２価の炭素数２〜１０の直鎖状アルキレン基または炭素数３〜１０の分岐鎖状アルキレン基を示す。〕

[In General Formula (2), R ⁵ represents a methylene group, a divalent linear alkylene group having 2 to 10 carbon atoms, or a branched alkylene group having 3 to 10 carbon atoms. ]

〔一般式（３）中Ｒ⁶はメチレン基または２価の炭素数２〜１０の直鎖状アルキレン基または炭素数３〜１０の分岐鎖状アルキレン基を示す。〕

[In the general formula (3), R ⁶ represents a methylene group, a divalent linear alkylene group having 2 to 10 carbon atoms or a branched alkylene group having 3 to 10 carbon atoms. ]

〔一般式（４）中Ｒ⁷はメチレン基または２価の炭素数２〜１０の直鎖状アルキレン基または炭素数３〜１０の分岐鎖状アルキレン基を示す。〕

[In the general formula (4), R ⁷ represents a methylene group, a divalent linear alkylene group having 2 to 10 carbon atoms, or a branched alkylene group having 3 to 10 carbon atoms. ]

〔一般式（５）中Ｒ⁸はメチレン基または２価の炭素数２〜１０の直鎖状アルキレン基または炭素数３〜１０の分岐鎖状アルキレン基を示す。〕

[In General Formula (5), R ⁸ represents a methylene group, a divalent linear alkylene group having 2 to 10 carbon atoms, or a branched alkylene group having 3 to 10 carbon atoms. ]

Specific examples of the group represented by the general formula (2) include a 2- (3 ′, 4′-epoxycyclohexyl) ethyl group.
Specific examples of the group represented by the general formula (3) include a 3-glycidoxy group.

Specific examples of the group represented by the general formula (4) include a 3-glycidoxypropyl group.
Specific examples of the group represented by the general formula (5) include a 2- (4′-methyl-3 ′, 4′-epoxycyclohexyl) ethyl group and the like.

  The polysiloxane (A) preferably has a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography in the range of 100 to 10000, and more preferably in the range of 500 to 5000. When the weight average molecular weight of the polysiloxane (A) is within the above range, it is easy to handle when producing an optical semiconductor encapsulating material using the composition, and the cured product obtained from the composition is an optical semiconductor encapsulating material. It has sufficient material strength and properties as a stopper.

  The polysiloxane (A) is contained in an amount of 40 to 95% by mass, preferably 50 to 90% by mass, and more preferably 55 to 85% by mass with respect to the total mass of the composition. When the content of the polysiloxane (A) is within the above range, the sealing material using the polysiloxane (A) has particularly excellent moisture resistance.

  As a method for producing the polysiloxane (A), known methods described in JP-A-6-9659, JP-A-2007-106798, JP-A-2007-169427, JP-A-2010-059359, and the like. For example, a method of hydrolyzing and condensing a silane compound with water as necessary in the presence of a reactive metal catalyst such as an acidic compound, a basic compound and titanium alkoxide can be mentioned.

Other components The composition for optical semiconductor encapsulation of the present invention may or may not contain the epoxy resin curing agent (B) for curing the resin component as described above. . In addition, the composition for optical semiconductor encapsulation of the present invention can contain various components as long as the object of the present invention can be achieved, and includes, for example, a curing accelerator, inorganic particles, an adhesion aid, an antiaging agent, and the like. can do. Moreover, the composition for optical semiconductor sealing of this invention can contain a fluorescent substance further. The composition for sealing an optical semiconductor containing a phosphor can be used as an LED sealing material for an LED having a wide wavelength band.

[Curing agent for epoxy resin (B)]
The epoxy resin curing agent (B) is a substance that cures the polysiloxane (A).
Examples of the epoxy resin curing agent (B) include acid anhydrides, secondary and tertiary amines, and metal chelate compounds. Among these, acid anhydrides are particularly preferable in that a sealing material having excellent heat resistance can be obtained without being colored.

(Acid anhydride)
The acid anhydride is not particularly limited, but alicyclic acid anhydrides such as alicyclic carboxylic acid anhydrides are preferred.
Examples of the alicyclic acid anhydride include compounds represented by the following formulas (6) to (16).

や、４−メチルテトラヒドロフタル酸無水物、メチルナジック酸無水物、ドデセニルコハク酸無水物のほか、α−テルピネン、アロオシメン等の共役二重結合を有する脂環式化合物と無水マレイン酸とのディールス・アルダー反応生成物やこれらの水素添加物等を挙げることができる。なお、前記ディールス・アルダー反応生成物やこれらの水素添加物としては、任意の構造異性体および任意の幾何異性体を使用することができる。

And Diels-Alder of maleic anhydride and alicyclic compounds having conjugated double bonds such as α-terpinene and alloocimene in addition to 4-methyltetrahydrophthalic anhydride, methylnadic acid anhydride, dodecenyl succinic anhydride Reaction products and hydrogenated products thereof can be exemplified. In addition, arbitrary structural isomers and arbitrary geometric isomers can be used as the Diels-Alder reaction product and hydrogenated products thereof.

  Siloxane-modified acid anhydrides can also be used. Such an acid anhydride is, for example, a hydrolyzate of a compound containing an acid anhydride and a double bond in one molecule such as 5-norbornene-2,3-dicarboxylic acid anhydride and a polysiloxane containing a hydride group. Obtained by silylation. As the hydrosilylation reaction product, any structural isomer and any geometric isomer can be used.

Moreover, the said alicyclic acid anhydride can also be chemically modified | denatured and used suitably, unless the hardening reaction is prevented substantially.
Among these alicyclic acid anhydrides, from the viewpoint of fluidity and transparency of the composition, the formula (6), the formula (8), the formula (10), the formula (11), the formula (12) and the formula ( The compound represented by 16) is preferred. Particularly preferred are compounds represented by formula (6), formula (8), formula (11) and formula (16).

In this invention, an alicyclic acid anhydride can be used individually or in mixture of 2 or more types.
In addition, one or more aliphatic acid anhydrides or aromatic acid anhydrides can be used as the acid anhydride. These are preferably used in combination with an alicyclic acid anhydride.

The aliphatic acid anhydride and aromatic acid anhydride can also be used after being appropriately chemically modified as long as the curing reaction is not substantially hindered.
The total use ratio of the aliphatic acid anhydride and the aromatic acid anhydride is preferably 50% by mass or less, more preferably 30% by mass or less, based on the total amount of these and the alicyclic acid anhydride.

  Content of the hardening | curing agent for epoxy resins (B) is 0.01-10 mass% normally with respect to the mass of the whole composition, Preferably it is 0.05-5 mass%, More preferably, it is 0.1-1 mass. %.

  When an acid anhydride is used as the epoxy resin curing agent (B), the amount used is equivalent ratio of acid anhydride group to 1 mol of epoxy group in polysiloxane (A) (acid anhydride equivalent / epoxy equivalent). 0.2 to 1.7, preferably 0.3 to 1.5, more preferably 0.5 to 1.3, and most preferably 0.6 to 0.8. In this case, even if the corresponding amount ratio is less than 0.2 or exceeds 1.7, there is a possibility that problems such as a decrease in the glass transition point (Tg) and coloring of the obtained cured product may occur.

[Curing accelerator]
The curing accelerator is a component that accelerates the curing reaction between the polysiloxane (A) and the epoxy resin curing agent (B).

As such a curing accelerator, compounds described in JP 2010-13619 A and the like can be used. For example,
Tertiary amines such as benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, cyclohexyldimethylamine, triethanolamine; special amines such as UCAT410 (San Apro Corporation);
Imidazoles such as 2-methylimidazole and 2-n-heptylimidazole;
Organophosphorus compounds such as diphenylphosphine, triphenylphosphine, triphenyl phosphite;
Quaternary phosphonium salts such as benzyltriphenylphosphonium chloride, tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium tetrafluoroborate;
Diazabicycloalkenes such as 1,8-diazabicyclo [5.4.0] undecene-7 and organic acid salts thereof;
Organometallic compounds such as zinc octylate, tin octylate, aluminum acetylacetone complex;
Quaternary ammonium salts such as tetraethylammonium bromide, tetra-n-butylammonium bromide, UCAT18X (San Apro Co., Ltd.);
Boron compounds such as boron trifluoride and triphenyl borate; metal halides such as zinc chloride and stannic chloride,
High melting point dispersion type latent curing accelerators such as amine addition accelerators such as dicyandiamide and adducts of amine and epoxy resin;
A microcapsule type latent curing accelerator in which the surface of a curing accelerator such as imidazoles, organophosphorus compounds and quaternary phosphonium salts is coated with a polymer;
An amine salt type latent curing agent accelerator;
Latent curing accelerators such as high temperature dissociation type thermal cationic polymerization type latent curing accelerators such as Lewis acid salts and Bronsted acid salts;
A radiation-sensitive acid generator described in JP-A-2008-192774;
Etc.

  Of these curing accelerators, imidazoles, quaternary phosphonium salts, diazabicycloalkenes, organometallic compounds, and quaternary ammonium salts are colorless and transparent, and a cured product that is difficult to discolor even when heated for a long time is obtained. This is preferable.

The said hardening accelerator can be used individually or in mixture of 2 or more types.
In the composition for optical semiconductor encapsulation of the present invention, the use amount of the curing accelerator is 0.005 to 6 parts by mass, preferably 0.01 to 5 parts by mass, further based on 100 parts by mass of the polysiloxane (A). Preferably it is 0.05-4 mass parts. When the amount of the curing accelerator used is less than 0.005 parts by mass, the effect of promoting the curing reaction tends to be reduced. On the other hand, when the amount exceeds 6 parts by mass, the resulting cured product may be inconvenient such as coloring. is there.

[Inorganic particles]
Examples of the inorganic particles include silica particles described in JP2010-13619A. When the composition for optical semiconductor encapsulation of the present invention contains silica particles as inorganic particles, it is preferable in terms of improving the strength and hardness of the cured film.

  When silica particles are blended as inorganic particles, they can also be used in the form of powder or a solvent-based sol or colloid dispersed in a polar solvent such as isopropyl alcohol or a nonpolar solvent such as toluene. In the case of a solvent-based sol or colloid, the solvent may be removed after compounding. In order to improve the dispersibility of the silica particles, a surface treatment may be performed.

  The usage-amount of an inorganic particle is normally 80 mass parts or less exceeding 0 mass part with respect to 100 mass parts of polysiloxane (A), Preferably it is 0.1 to 50 mass parts.

[Adhesion aid]
The composition for optical semiconductor encapsulation of the present invention contains an adhesion assistant, particularly for the purpose of improving the adhesion between the encapsulant and the reflector or electrode of the light emitting device.

As the adhesion assistant, compounds described in JP 2010-13619 A and the like can be used. For example, the following substances can be mentioned.
An organic compound containing at least two epoxy groups in the molecule and having a molecular weight of 100 to 1500, such as an alicyclic epoxy group-containing compound such as an epoxycycloalkyl group or a compound having a glycidoxyalkyl group ;
An epoxy group-containing alkoxysilane represented by the following formula (17) and the following formula (18)

〔式（１７）中、Ｒ^Eはエポキシ基を含有する有機基、Ｒ¹およびＲ³はそれぞれ独立に非置換または置換の１価の炭化水素基を示し、ｍは１または２、ｎは２または３、かつｍ＋ｎ≦４である。〕

[In formula (17), R ^E represents an organic group containing an epoxy group, R ¹ and R ³ each independently represents an unsubstituted or substituted monovalent hydrocarbon group, m is 1 or 2, and n is 2 Or 3 and m + n ≦ 4. ]

（式（１８）中、Ｒ⁵およびＲ⁶はそれぞれ独立に非置換または置換の１価の炭化水素基を示し、ｐは０〜２の整数である。）
で表されるアルコキシシランとの加水分解縮合物や、シラノール基を含有しないエポキシ基含有ポリジメチルシロキサンの如き、ポリシロキサン（Ａ）以外のエポキシ基含有ポリシロキサン； １，４−ビス｛［（３−エチルオキセタン−３−イル）メトキシ］メチル｝ベンゼン（商品名「ＯＸＴ−１２１」、東亜合成社製）、３−エチル−３−｛［（３−エチルオキセタン−３−イル）メトキシ］メチル｝オキセタン（商品名「ＯＸＴ−２２１」、東亜合成社製）、ビス〔（３−エチル−３−オキセタニルメトキシ）メチル−フェニル〕エーテル、ビス〔（３−エチル−３−オキセタニルメトキシ）メチル−フェニル〕プロパンの如きオキセタン化合物；
３−メルカプトプロピルトリメトキシシラン、３−メルカプトプロピルトリエトキシシランの如きチオール化合物；
イソシアヌル酸トリス（３−トリメトキシシリル−ｎ−プロピル）、イソシアヌル酸トリス（２−ヒドロキシエチル）、イソシアヌル酸トリグリシジルの如きイソシアヌル環構造を有する化合物；
上述した式（１８）で表されるアルコキシシランやその加水分解物、またはその縮合物の如きアルコキシシランやその加水分解物または縮合物；が挙げられる。

(In formula (18), R ⁵ and R ⁶ each independently represents an unsubstituted or substituted monovalent hydrocarbon group, and p is an integer of 0 to 2.)
An epoxy group-containing polysiloxane other than polysiloxane (A), such as a hydrolysis-condensation product with an alkoxysilane represented by formula (1) or an epoxy group-containing polydimethylsiloxane not containing a silanol group; 1,4-bis {[(3 -Ethyloxetane-3-yl) methoxy] methyl} benzene (trade name “OXT-121”, manufactured by Toa Gosei Co., Ltd.), 3-ethyl-3-{[((3-ethyloxetane-3-yl) methoxy] methyl} Oxetane (trade name “OXT-221”, manufactured by Toa Gosei Co., Ltd.), bis [(3-ethyl-3-oxetanylmethoxy) methyl-phenyl] ether, bis [(3-ethyl-3-oxetanylmethoxy) methyl-phenyl] Oxetane compounds such as propane;
Thiol compounds such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane;
Compounds having an isocyanuric ring structure such as isocyanuric acid tris (3-trimethoxysilyl-n-propyl), isocyanuric acid tris (2-hydroxyethyl), isocyanuric acid triglycidyl;
And alkoxysilanes and hydrolysates or condensates thereof, such as alkoxysilanes represented by the formula (18) and hydrolysates or condensates thereof.

  The adhesion assistant may be added at the time of synthesizing the polysiloxane (A) or may be added at the time of forming the cured body.

[Other additives]
Other additives include antioxidants and light stabilizers.

  The said antioxidant is used from the point of the heat resistance improvement of a sealing material. As an antioxidant, Preferably a hindered phenolic antioxidant can be mix | blended with 0.1-5 mass parts with respect to 100 mass parts of (A) component. As the antioxidant, compounds described in JP 2010-13619 A and the like can be used.

  The light stabilizer is used in terms of improving the light resistance of the sealing material. The light stabilizer can be contained in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of the polysiloxane (A). As the light stabilizer, compounds described in JP 2010-13619 A and the like can be used.

<Encapsulant>
A sealing material is obtained by curing the composition for optical semiconductor encapsulation of the present invention. Examples of the method for curing the composition for optical semiconductor encapsulation include a method in which the composition for optical semiconductor encapsulation is applied on a substrate and then heated at 100 to 180 ° C. for 3 to 13 hours. In addition, as above-mentioned, when using a hardening | curing agent (B) for the composition for optical semiconductor sealing, the composition for optical semiconductor sealing is prepared just before making it harden | cure, Then, the composition for optical semiconductor sealing is on a board | substrate. It can be cured by coating and heat treatment.

  As described above, the encapsulant obtained by curing the composition for optical semiconductor encapsulation of the present invention is excellent in heat resistance and the like and excellent in moisture permeability.

<Light emitting element>
The light emitting element according to the present invention is obtained by sealing an optical semiconductor using the optical semiconductor sealing composition. When sealing an optical semiconductor using the composition, the composition can be cured by a known method. For example, after apply | coating this composition, it can be made to harden | cure by heating at 100-180 degreeC for 3 to 13 hours, and the hardening body which is a sealing material can be formed. Curing may be performed in a process of stepwise temperature rise (step cure).

Examples of the optical semiconductor include an LED (Light Emitting Diode) and an LD (Laser Diode).
FIG. 1 is a schematic view of a light emitting device obtained by encapsulating an optical semiconductor with the composition for encapsulating an optical semiconductor of the present invention, that is, a light emitting device 1 as a specific example of the light emitting device according to the present invention. The light-emitting element 1 includes an electrode 6, an optical semiconductor 2 installed on the electrode 6 and electrically connected to the electrode 6 by a wire 7, a reflector 3 disposed so as to receive the optical semiconductor 2, and a reflector 3. It has the sealing material 4 with which it fills in and seals the optical semiconductor 2. The sealing material 4 is obtained by curing the optical semiconductor sealing composition of the present invention. Silica particles 5 are dispersed in the sealing material 4.

  As described above, the encapsulant obtained by curing the composition for optical semiconductor encapsulation of the present invention is excellent in heat resistance and the like and excellent in moisture permeability. For this reason, the light-emitting element obtained by encapsulating the optical semiconductor with the composition for encapsulating an optical semiconductor of the present invention can be used stably over a long period without deterioration of the optical semiconductor due to water vapor that passes through the sealing material. can do.

1. Synthesis of polysiloxane The weight average molecular weight and epoxy equivalent of polysiloxane were measured by the following methods.
1-1. Weight average molecular weight (Mw)
The weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC) under the following conditions and determined as a polystyrene equivalent value.

Apparatus: HLC-8120C (manufactured by Tosoh Corporation)
Column: TSK-gel Multipore HXL-M (manufactured by Tosoh Corporation)
Eluent: THF, flow rate 0.5 mL / min, load 5.0%, 100 μL
1-2. Epoxy equivalent Based on JIS C2105, the epoxy equivalent of the obtained polysiloxane was measured.
1-3. Content ratio of specific structural units
The content ratio of the specific structural unit was measured by ² H NMR.

[Synthesis Example 1] Synthesis of polysiloxane (A1) In a reaction vessel, 20 parts of diphenyldimethoxysilane (a1-1), 8 parts of 2- (3 ′, 4′-epoxycyclohexyl) ethyltrimethoxysilane (a2-1) After mixing 8 parts of dimethyldimethoxysilane (a3-1) and 3 parts of diazabicycloundecene, the mixture was heated at 50 ° C. for 8 hours.

  To the mixed liquid after heating, 75 parts of methyl isobutyl ketone, 25 parts of methanol and 25 parts of water were added to obtain a two-layer liquid comprising an aqueous layer and an organic layer. After stirring the two-layer solution at 25 ° C. for 1 hour, 30 parts of a 6% oxalic acid aqueous solution was added and stirred at 25 for 1 hour. After stirring, the organic layer of the two-layer liquid was taken out, and this organic layer was washed with water three times. After washing, methyl isobutyl ketone, methanol, ethanol and water were distilled off from this organic layer to obtain polysiloxane (A1). This polysiloxane had an Mw of 1000, an epoxy equivalent of 900, and a specific structural unit content of 55% by mass.

[Synthesis Examples 2 to 10] Synthesis of Polysiloxanes (A2) to (A7) and (AR1) to (AR3) Polysiloxanes were synthesized in the same manner as in Synthesis Example 1 except that the compounds shown in Table 1 below were used. (A2) to (A7) and (AR1) to (AR3) were obtained. The details of the compounds in Table 1 are as follows. Further, the Mw, epoxy equivalent and content ratio of the specific structure of these polysiloxanes are appended in Table 1.

a1-1: Diphenyldimethoxysilane a1-2: Diphenylsilanediol a2-1: 2- (3 ′, 4′-epoxycyclohexyl) ethyltrimethoxysilane a3-1: Dimethyldimethoxysilane a3-2: Cyclohexylmethyldimethoxysilane a3 -3: Phenyltrimethoxysilane a3-4: Hydroxy-terminated polydimethylsiloxane (trade name “XC96-723” manufactured by Momentive Co., Ltd.)
a3-5: Vinyltrimethoxysilane

［合成例１１］ビス（ジメチルシリル）ジフェニルシロキサン（Ｃ２）の合成
反応容器に、ジフェニルジメトキシシラン（ａ１−１）２４０部、１，１、３，３−テトラメチルジシロキサン１３４部およびトリフルオロメタンスルホン酸０．７４部を２５℃で混合した。混合液に酢酸３６０部を加え、混合液を５０℃で３時間攪拌した。

[Synthesis Example 11] Synthesis of bis (dimethylsilyl) diphenylsiloxane (C2) In a reaction vessel, 240 parts of diphenyldimethoxysilane (a1-1), 134 parts of 1,1,3,3-tetramethyldisiloxane and trifluoromethanesulfone 0.74 parts of acid was mixed at 25 ° C. 360 parts of acetic acid was added to the mixture, and the mixture was stirred at 50 ° C. for 3 hours.

  The heated solution was cooled to room temperature, and 500 parts of toluene was added. This solution was washed three times with water. The organic layer after washing was transferred to a reaction vessel equipped with a Dean Stark and heated at 110 ° C. The reaction solution was distilled off under reduced pressure to obtain bis (dimethylsilyl) diphenylsiloxane (C2).

2. Preparation of composition for optical semiconductor encapsulation [Examples 1 to 9 and Comparative Examples 1 to 3]
By mixing the components shown in Table 2 in the proportions shown in Table 2, compositions for optical semiconductor encapsulation of Examples 1 to 9 and Comparative Examples 1 to 3 were prepared. In addition, the detail of the hardening | curing agent for epoxy resins (B1-B2) and other components (C1-C2) is as follows.
B1: Mixture of hexahydrophthalic anhydride and methylhexahydrophthalic anhydride (trade name “MH-700G”, manufactured by Shin Nippon Science Co., Ltd.).
B2: 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate (trade name “Celoxide 2021P”, manufactured by Daicel Chemical Industries, Ltd.).
C1: Toluene solution containing 0.3% by weight of platinum (0) divinyltetramethyldisiloxane C2: Bis (dimethylsilyl) diphenylsiloxane

３．光半導体封止用組成物の評価
上記『２．光半導体封止用組成物の調製』で得た実施例１〜９および比較例１〜３の光半導体封止用組成物について下記３−１〜３−５の評価を行った。結果を上記表３に示す。

3. Evaluation of composition for optical semiconductor sealing [2. Evaluation of the following 3-1 to 3-5 was performed about the composition for optical semiconductor sealing of Examples 1-9 and Comparative Examples 1-3 obtained by preparation of the composition for optical semiconductor sealing. The results are shown in Table 3 above.

3-1. Moisture permeability resistance The composition for optical semiconductor sealing was apply | coated on the peeling film, and the coating film was heated at 100 degreeC for 1 hour, and then at 150 degreeC for 5 hours. Next, the release film was peeled off from the coating film to obtain a 200 μm-thick film (a sample for moisture permeability evaluation).

The water vapor permeability of the moisture permeation resistance evaluation sample was measured with a water vapor permeability measuring device (trade name “PERMATRAN-W 3/31”, manufactured by MOCON) according to the MOCON method. The moisture permeability resistance was evaluated according to the following evaluation criteria.
A: Water vapor transmission rate is less than 50 g / m ² / day.
B: Water vapor transmission rate is 50 to 100 g / m ² / day.
C: Water vapor transmission rate is greater than 100 g / m ² / day.

3-2. Heat resistance After applying the composition for encapsulating an optical semiconductor on quartz glass so that the dry film thickness becomes 1 mm, it is dried and cured at 100 ° C. for 1 hour, and then dried and cured at 150 ° C. for 5 hours. A sample for heat resistance evaluation was prepared. This sample for heat resistance evaluation was stored at 150 ° C. for 500 hours, and the appearance of the cured body after storage was visually observed to evaluate the heat resistance. The evaluation criteria are as follows.
A: No color change B: Slightly discolored C: Clear yellow

3-3. Peeling resistance An optical semiconductor sealing composition is injected into an LED package (surface-mounting type, top-view type, part constituted by the optical semiconductor 2, the electrode 6, the wire 7 and the reflector 3 in FIG. 1) at 100 ° C. It was dried and cured for 1 hour, and then dried and cured at 150 ° C. for 5 hours to prepare a cured body sample. The obtained cured body sample was stored in a constant temperature and humidity chamber (Espec SP-3KP) at 85 ° C. and 85% RH for 5 hours, and then a tabletop solder reflow apparatus (STR-2010 manufactured by Senju Metal Industry Co., Ltd.) was used. The heat treatment was performed twice at 260 ° C. for 10 seconds. Separation between the cured product in the package after reflow treatment and the package resin was observed with an optical microscope. Ten cured samples were prepared for each composition for optical semiconductor encapsulation, the same observation was performed on each sample, and the peel resistance was evaluated according to the following criteria.
A: No peeling occurred in all samples after storage for 5 hours B: 1-2 occurrences of peeling in 10 samples after storage for 5 hours C: 3 or more occurrences of peeling in 10 samples after storage for 5 hours

3-4. Thermal shock resistant composition for optical semiconductor encapsulation is injected into an LED package (surface mounted type, top view type, part constituted by optical semiconductor 2, electrode 6, wire 7 and reflector 3 in FIG. 1) at 100 ° C. A sample for evaluation of thermal shock resistance was prepared by heating for 1 hour at 150 ° C. for 3 hours.

Using a thermal shock test apparatus (trade name “TOM17”, manufactured by ESPEC), a temperature increase from −40 ° C. to 100 ° C. at a rate of 1 ° C./min with respect to the thermal shock resistance evaluation sample. A thermal shock test in which cooling from 100 ° C. to −40 ° C. was 1 cycle was performed 1000 cycles. Ten samples for evaluation of thermal shock resistance were prepared for each composition for optical semiconductor encapsulation, and the same test was performed on each sample. The sample for evaluating thermal shock resistance after 1000 cycles was observed using an optical microscope, and the presence or absence of peeling between the package and the resin and cracks inside the resin was visually evaluated. The evaluation criteria are as follows.
Existence of peeling A: No peeling on all samples B: Separation occurred in 1 to 4 samples out of 10 between package and resin C: 5 or more samples out of 10 between package and resin A: No cracks occurred in all samples B: Cracks occurred in 1 to 4 out of 10 samples inside the resin C: Cracks occurred in 5 or more out of 10 samples inside the resin There has occurred

3-5. Electrode blackening suppression ability An optical semiconductor sealing composition is injected into an LED package (surface-mounting type, top view type, portion constituted by the optical semiconductor 2, the electrode 6, the wire 7, and the reflector 3 in FIG. 1). A sample for evaluating electrode blackening suppression ability was prepared by heating at 100 ° C. for 1 hour and subsequently at 150 ° C. for 3 hours.

After the sample for evaluating electrode blackening suppression ability was allowed to stand in a pressure-resistant container (volume: 1 L), hydrogen sulfide gas was fed so that 10% by volume of the sample was hydrogen sulfide. Thereafter, the pressure vessel was heated at 80 ° C. for 24 hours. About the discoloration condition of the silver electrode of the sample for electrode blackening suppression ability evaluation after a heating, it observed by visual observation with the optical microscope, and evaluated electrode blackening suppression ability. The evaluation criteria are as follows.
A: The silver electrode is the same silver color as the silver electrode of the LED package.
B: The silver electrode part turned yellow.
C: The silver electrode part changed to black.

1 .. Light emitting element 2 .. Optical semiconductor 3 .. Reflector 4 .. Sealing material 5 .. Silica particle 6 .. Electrode 7 .. Wire

Claims (5)

An optical semiconductor sealing composition comprising 40 to 95% by mass of polysiloxane (A) having an epoxy group and having a repeating structural unit represented by the following formula (1).

(In the formula (1), Ar represents an aryl group.)   The composition for optical semiconductor sealing according to claim 1, wherein a content ratio of the repeating structural unit represented by the formula (1) contained in the polysiloxane (A) is 20 to 80% by mass.   Furthermore, the composition for optical semiconductor sealing in any one of Claims 1-2 containing the said hardening | curing agent for epoxy resins (B).   The composition for optical semiconductor encapsulation according to claim 3, wherein the epoxy resin curing agent (B) is an acid anhydride.   The light emitting element formed by sealing an optical semiconductor using the composition for optical semiconductor sealing in any one of Claims 1-4.

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