Patent Application
20170190879
The present invention relates to a novel adhesion promoter, a curable silicone composition containing the adhesion promoter, and a semiconductor device using the curable silicone composition.
Since a hydrosilylation curable silicone composition typically has poor adhesion to metals and organic resins, especially to base materials of thermoplastic resins or the like, the following proposals have been made, for example. A curable silicone composition comprising: an organopolysiloxane having an alkenyl group bonded to a silicon atom; an organohydrogenpolysiloxane having a silicon atom-bonded hydrogen atom; an adhesion promoter containing an isocyanuric acid derivative having at least one type of functional group selected from the group consisting of epoxy groups, glycidoxy groups, and alkoxysilyl groups, and at least one type of group selected from the group consisting of crosslinkable vinyl groups and hydrosilyl groups (Si—H groups); and a hydrosilylation reaction catalyst has been proposed (see Patent Document 1). A curable silicone composition comprising: an organopolysiloxane having at least two alkenyl groups in a molecule; an organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms in a molecule; an isocyanuric ring-containing organosiloxane having an allyl group, an epoxy group, and an organosiloxy group in a molecule; and a hydrosilylation reaction catalyst has been proposed (see Patent Document 2). A curable silicone composition comprising: an organopolysiloxane having an alkenyl group bonded to a silicon atom; an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom; an adhesion promoter comprising an isocyanuric acid derivative having an alkoxysilyl group and/or an epoxy group, and a divalent siloxy unit-containing group, and a silane or siloxane compound having an alkoxy group and/or an epoxy group but having no isocyanuric ring; and a hydrosilylation reaction catalyst has been proposed (Patent Document 3).
However, there has been a problem in that adhesion to base materials that are in contact even with these curable silicone compositions during curing is not sufficient.
An object of the present invention is to provide a novel adhesion promoter, a curable silicone composition that contains the adhesion promoter and that forms a cured product having excellent adhesion to various base materials, and a semiconductor device that is formed from the curable silicone composition and that has excellent reliability.
The adhesion promoter of the present invention is represented by the average formula:
wherein, R1 are the same or different monovalent hydrocarbon groups having from 1 to 12 carbons but having no aliphatic unsaturated bond, X is a glycidoxyalkyl group, an epoxycycloalkylalkyl group, or an epoxyalkyl group, m and n are numbers satisfying: 1<m<3, 1<n<3, and m+n=3, and p is an integer of 1 to 50.
The curable silicone composition of the present invention contains the adhesion promoter described above and preferably is cured by hydrosilylation reaction. The curable silicone composition of the present invention more preferably comprises:
(A) 100 parts by mass of an organopolysiloxane having at least two alkenyl groups in a molecule;
(B) an organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms in a molecule, in an amount such that provides from 0.1 to 10 mol of silicon atom-bonded hydrogen atom per 1 mol total of alkenyl groups contained in components (A) and (C);
(C) from 0.01 to 20 parts by mass of the adhesion promoter described above; and
(D) a hydrosilylation reaction catalyst, in an amount such that promotes curing of the present composition.
The semiconductor device of the present invention has a semiconductor element encapsulated with a cured product of the curable silicone composition described above, and preferably the semiconductor element is a light emitting element.
The adhesion promoter of the present invention is a novel compound and can impart excellent adhesion to a curable silicone composition. The curable silicone composition of the present invention forms a cured product having excellent adhesion to various base materials that are in contact with the curable silicone composition during curing. Furthermore, the semiconductor device of the present invention has excellent reliability since a semiconductor element is encapsulated with the cured product of the composition.
First, the adhesion promoter of the present invention will be described in detail.
The adhesion promoter of the present invention is represented by the average formula:
In the formula, R1 are the same or different monovalent hydrocarbon groups having from 1 to 12 carbons but having no aliphatic unsaturated bond. Specific examples thereof include alkyl groups, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group; aryl groups, such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group; aralkyl groups, such as a benzyl group, a phenethyl group, and a phenylpropyl group; and groups in which some or all of the hydrogen atoms in these groups are substituted with halogen atoms, such as fluorine atoms, chlorine atoms, and bromine atoms. Of these, a methyl group and a phenyl group are preferable.
In the formula, X is a glycidoxyalkyl group, an epoxycycloalkylalkyl group, or an epoxyalkyl group. Examples of the glycidoxyalkyl group include a 2-glycidoxyethyl group, a 3-glycidoxypropyl group, and a 4-glycidoxybutyl group. Examples of the epoxycycloalkylalkyl group include a 2-(3,4-epoxycyclohexyl)-ethyl group and a 3-(3,4-epoxycyclohexyl)-propyl group. Examples of the epoxyalkyl group include a 3,4-epoxybutyl group and a 7,8-epoxyoctyl group.
In the formula, m and n are numbers satisfying: 1<m<3, 1<n<3, and m+n=3. This is because, when m is a number greater than 1, that is, n is a number less than 3, adhesion of the curable silicone composition can be enhanced, and on the other hand, when m is a number less than 3, that is, n is a number greater than 1, the present adhesion promoter readily reacts with the silicon atom-bonded hydrogen atom in the hydrosilylation curable silicone composition.
In the formula, p is a number in a range of 1 to 50, and from the perspective of enhancing adhesion of the curable silicone composition, p is preferably a number in a range of 1 to 30, and more preferably a number in a range of 1 to 10.
The method of preparing such an adhesion promoter is not limited, and examples thereof include a method in which triallylisocyanurate and a siloxane represented by the average formula:
wherein, R1, X, and p are the same as those described above,
are subjected to hydrosilylation reaction in the presence of a hydrosilylation reaction catalyst.
In the siloxane described above, R1 in the formula are the same or different monovalent hydrocarbon groups having from 1 to 12 carbons but having no aliphatic unsaturated bond, and examples thereof are the same as the groups described above. Furthermore, in the formula, X is a glycidoxyalkyl group, an epoxycycloalkylalkyl group, or an epoxyalkyl group, and examples thereof are the same as the groups described above. Furthermore, in the formula, p is a number in a range of 1 to 50, preferably a number in a range of 1 to 30, and more preferably a number in a range of 1 to 10.
In the preparation method described above, less than the equivalent amount of the silicon atom-bonded hydrogen atom in the siloxane described above needs to be reacted with the allyl group in the triallylisocyanurate. The reaction is preferably performed in amounts where preferably 0.5 mol to 2 mol, and more preferably 0.75 mol to 1.5 mol, of the silicon atom-bonded hydrogen atom in the siloxane is reacted with 3 mol of allyl group in the triallylisocyanurate.
Examples of the hydrosilylation reaction catalyst used in the preparation method described above include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts, and platinum-based catalysts are particularly preferable. Examples of the platinum-based catalyst include platinum-based compounds, such as finely powdered platinum, platinum black, platinum-supported silica fine powder, platinum-supported activated carbon, chloroplatinic acid, alcohol solutions of chloroplatinic acid, olefin complexes of platinum, and alkenylsiloxane complexes of platinum.
An organic solvent may be used in the preparation method described above. The utilized organic solvent is exemplified by ethers, ketones, acetates, aromatic or aliphatic hydrocarbons, and a γ-butyrolactone; and mixtures of two or more types of such solvents. Preferred organic solvents are exemplified by propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol mono-t-butyl ether, γ-butyrolactone, toluene, and xylene.
In the preparation method described above, hydrosilylation reaction is promoted by heating. When an organic solvent is used, the reaction is preferably performed at the reflux temperature of the organic solvent.
Next, a curable silicone composition of the present invention will be described in detail.
The curable silicone composition of the present invention contains the adhesion promoter described above. The curing mechanism of such a curable silicone composition is not limited, and examples thereof include hydrosilylation reactions, condensation reactions, and radical reactions, and hydrosilylation reactions are preferable. The hydrosilylation curable silicone composition preferably comprises:
(A) 100 parts by mass of an organopolysiloxane having at least two alkenyl groups in a molecule;
(B) an organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms in a molecule, in an amount such that provides from 0.1 to 10 mol of silicon atom-bonded hydrogen atom per 1 mol total of alkenyl groups contained in components (A) and (C);
(C) from 0.01 to 20 parts by mass of the adhesion promoter described above; and
(D) a hydrosilylation reaction catalyst.
Component (A) is the base compound of the present composition and is an organopolysiloxane having at least two alkenyl groups in a molecule. Examples of the alkenyl groups in component (A) include alkenyl groups having from 2 to 12 carbons, such as a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, a undecenyl group, and a dodecenyl group. Of these, a vinyl group is preferable. Furthermore, examples of the group bonded to the silicon atom other than alkenyl group in component (A) include alkyl groups having from 1 to 12 carbons, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group; aryl groups having from 6 to 20 carbons, such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group; aralkyl groups having from 7 to 20 carbons, such as a benzyl group, a phenethyl group, and a phenylpropyl group; and groups in which some or all of the hydrogen atoms in these groups are substituted with halogen atoms, such as fluorine atoms, chlorine atoms, and bromine atoms. Note that the silicon atom in component (A) may have a small amount of a hydroxy group and/or an alkoxy group, such as a methoxy group and an ethoxy group, at levels that do not impair the object of the present invention.
The molecular structure of component (A) is not particularly limited, and examples thereof include straight, partially branched straight, branched, cyclic, and three-dimensional network structures. Component (A) may be one type of organopolysiloxane having such a molecular structure, or may be a mixture of two or more types of organopolysiloxanes having such molecular structures.
The state of component (A) at 25° C. is not particularly limited and, for example, may be liquid or solid. When component (A) is liquid, the viscosity at 25° C. is preferably in a range of 1 to 1,000,000 mPa·s, and particularly preferably in a range of 10 to 1,000,000 mPa·s. Note that this viscosity can be determined by, for example, measurement using a B type viscometer in accordance with JIS K 7117-1.
Examples of component (A) include dimethylpolysiloxane capped at both molecular terminals with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers capped at both molecular terminals with dimethylvinylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers capped at both molecular terminals with dimethylvinylsiloxy groups, methylphenylpolysiloxane capped at both molecular terminals with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers capped at both molecular terminals with trimethylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers capped at both molecular terminals with trimethylsiloxy groups, copolymers comprising (CH3)3SiO1/2 units, (CH3)2(CH2═CH)SiO1/2 units, and SiO4/2 units, copolymers comprising (CH3)2(CH2═CH)SiO1/2 units and SiO4/2 units, and the following organopolysiloxanes. Note that, in the formulas, Me represents a methyl group, Vi represents a vinyl group, Ph represents a phenyl group, and x and x′ are each independently an integer of 1 to 5,000.
ViMe2SiO(Me2SiO)xSiMe2Vi
ViPhMeSiO(Me2SiO)xSiMePhVi
ViPh2SiO(Me2SiO)xSiPh2Vi
ViMe2SiO(Me2SiO)x(Ph2SiO)x′SiMe2Vi
ViPhMeSiO(Me2SiO)x(Ph2SiO)x′SiPhMeVi
ViPh2SiO(Me2SiO)x(Ph2SiO)x′SiPh2Vi
ViMe2SiO(MePhSiO)zSiMe2Vi
MePhViSiO(MePhSiO)xSiMePhVi
Ph2ViSiO(MePhSiO)xSiPh2Vi
ViMe2SiO(Ph2SiO)x(PhMeSiO)x′SiMe2Vi
ViPhMeSiO(Ph2SiO)x(PhMeSiO)x′SiPhMeVi
ViPh2SiO(Ph2SiO)x(PhMeSiO)x′SiPh2Vi
Component (B) is a crosslinking agent of the present composition and is an organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms in a molecule. Examples of the molecular structure of component (B) include straight, partially branched straight, branched, cyclic, and dendritic structures. Of these, straight, partially branched straight, and dendritic structures are preferable. The bonding positions of the silicon atom-bonded hydrogen atoms in component (B) are not limited, and examples thereof include a molecular terminal(s) and/or side chain(s). Furthermore, examples of the silicon atom-bonded group other than the hydrogen atom in component (B) include alkyl groups, such as a methyl group, an ethyl group, and a propyl group; aryl groups, such as a phenyl group, a tolyl group, and a xylyl group; aralkyl groups, such as a benzyl group and a phenethyl group; and halogenated alkyl groups, such as a 3-chloropropyl group and a 3,3,3-trifluoropropyl group; and a methyl group and a phenyl group are preferable. Furthermore, although the viscosity of component (B) is not limited, the viscosity at 25° C. is preferably in a range of 1 to 10,000 mPa·s, and particularly preferably in a range of 1 to 1,000 mPa·s.
Examples of component (B) include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tris(dimethylhydrogensiloxy)methylsilane, tris(dimethylhydrogensiloxy)phenylsilane, 1-glycidoxypropyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1,5-glycidoxypropyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1-glycidoxypropyl-5-trimethoxysilylethyl-1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrogenpolysiloxane capped at both molecular terminals with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymers capped at both molecular terminals with trimethylsiloxy groups, dimethylpolysiloxane capped at both molecular terminals with dimethylhydrogensiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymers capped at both molecular terminals with dimethylhydrogensiloxy groups, methylhydrogensiloxane-diphenylsiloxane copolymers capped at both molecular terminals with trimethylsiloxy groups, methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymers capped at both molecular terminals with trimethylsiloxy groups, hydrolysis condensates of trimethoxysilane, copolymers comprising (CH3)2HSiO1/2 units and SiO4/2 units, copolymers comprising (CH3)2HSiO1/2 units, SiO4/2 units, and (C6H5)SiO3/2 units, and the following organohydrogenpolysiloxane. Note that, in the formulas, Me represents a methyl group, Vi represents a vinyl group, Ph represents a phenyl group, Naph represents a naphthyl group, and y and y′ are each independently an integer of 1 to 100, c, d, e, and f are positive numbers but the total of c, d, e, and f is 1.
HMe2SiO(Ph2SiO)ySiMe2H
HMePhSiO(Ph2SiO)ySiMePhH
HMeNaphSiO(Ph2SiO)ySiMeNaphH
HMePhSiO(Ph2SiO)y(MePhSiO)y′SiMePhH
HMePhSiO(Ph2SiO)y(Me2SiO)y′SiMePhH
(HMe2SiO1/2)c(PhSiO3/2)d
(HMePhSiO1/2)c(PhSiO3/2)d
(HMePhSiO1/2)c(NaphSiO3/2)d
(HMe2SiO1/2)c(NaphSiO3/2)d
(HMePhSiO1/2)c(HMe2SiO1/2)d(PhSiO3/2)e
(HMe2SiO1/2)c(Ph2SiO2/2)d(PhSiO3/2)e
(HMePhSiO1/2)c(Ph2SiO2/2)d(PhSiO3/2)e
(HMe2SiO1/2)c(Ph2SiO2/2)d(NaphSiO3/2)e
(HMePhSiO1/2)c(Ph2SiO2/2)d(NaphSiO3/2)e
(HMePhSiO1/2)c(HMe2SiO1/2)d(NaphSiO3/2)e
(HMePhSiO1/2)c(HMe2SiO1/2)d(Ph2SiO2/2)e(NaphSiO3/2)f
(HMePhSiO1/2)c(HMe2SiO1/2)d(Ph2SiO2/2)e(PhSiO3/2)f
The content of component (B) is in an amount such that the amount of the silicon atom-bonded hydrogen atom of the present composition is from 0.1 to 10 mol, and preferably from 0.5 to 5 mol, per 1 mol total of alkenyl groups contained in components (A) and (C). This is because, when the content of component (B) is less than or equal to the upper limit of the range described above, excellent mechanical characteristics of the resulting cured product is achieved, and on the other hand, when the content of component (B) is greater than or equal to the lower limit of the range described above, excellent curability of the resulting composition is achieved.
Component (C) is an adhesion promoter for imparting adhesion to the present composition and is a compound that is as described above. The content of component (C) is in a range of 0.01 to 20 parts by mass, and preferably in a range of 0.1 to 10 parts by mass, per 100 parts by mass of component (A). This is because, when the content of component (C) is greater than or equal to the lower limit of the range described above, sufficient adhesion can be imparted to the resulting composition, and on the other hand, when the content of component (C) is less than or equal to the upper limit of the range described above, curability of the resulting composition is less likely to be deteriorated and coloring or the like of the resulting cured product can be suppressed.
Component (D) is a hydrosilylation reaction catalyst for accelerating the curing of the present composition, and examples thereof include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts. Particularly, component (D) is preferably a platinum-based catalyst so that the curing of the present composition can be dramatically accelerated. Examples of the platinum-based catalyst include a platinum fine powder, chloroplatinic acid, an alcohol solution of chloroplatinic acid, a platinum-alkenylsiloxane complex, a platinum-olefin complex and a platinum-carbonyl complex, and the platinum-alkenylsiloxane complex is preferred.
The content of component (D) is in an amount such that promotes the curing of the present composition. Specifically, the content of component (D) is preferably an amount so that the catalyst metal in component (D) is in a range of 0.01 to 500 ppm, more preferably in a range of 0.01 to 100 ppm, and particularly preferably in a range of 0.01 to 50 ppm, in a mass unit, relative to the amount of the present composition.
Furthermore, the present composition may contain (E) a hydrosilylation reaction inhibitor, as an optional component, such as alkyne alcohols, such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, and 2-phenyl-3-butyn-2-ol; ene-yne compounds, such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, and benzotriazole. In the present composition, although the content of component (E) is not limited, the content of component (E) is preferably in a range of 0.0001 to 5 parts by mass per 100 parts by mass total of components (A) to (D).
Furthermore, the present composition may also contain an adhesion promoter other than component (C) to enhance the adhesion of the cured product to a base material which is in contact with the present composition during the curing. As this adhesion promoter, an organosilicon compound having at least one alkoxy group bonded to a silicon atom in a molecule is preferable. This alkoxy group is exemplified by a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a methoxyethoxy group; and the methoxy group is particularly preferred. Furthermore, examples of other groups, excluding the alkoxy group bonded to the silicon atom of the organosilicon compound, include substituted or unsubstituted monovalent hydrocarbon groups, such as an alkyl group, an alkenyl group, an aryl group, an aralkyl group, and a halogenated alkyl group; glycidoxyalkyl groups, such as a 3-glycidoxypropyl group and a 4-glycidoxybutyl group; epoxycyclohexylalkyl groups, such as a 2-(3,4-epoxycyclohexyl)ethyl group and a 3-(3,4-epoxycyclohexyl)propyl group; epoxyalkyl groups, such as a 3,4-epoxybutyl group and a 7,8-epoxyoctyl group; acrylic group-containing monovalent organic groups, such as a 3-methacryloxypropyl group; and a hydrogen atom. This organosilicon compound preferably has a silicon-bonded alkenyl group or silicon-bonded hydrogen atom. Examples of such an organosilicon compound include organosilane compounds, organosiloxane oligomers, and alkyl silicates. Examples of the molecular structure of the organosiloxane oligomer or alkyl silicate include straight, partially branched straight, branched, cyclic, and net-shaped structures. Straight, branched, and net-shaped structures are particularly preferred. Examples of such an organosilicon compound include silane compounds such as 3-glycidoxypropyl trimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, and 3-methacryloxypropyl trimethoxysilane; siloxane compounds having at least one of silicon-bonded alkenyl groups and silicon-bonded hydrogen atoms, and at least one silicon-bonded alkoxy group in a molecule; mixtures of a silane compound or siloxane compound having at least one silicon-bonded alkoxy group and a siloxane compound having at least one silicon-bonded hydroxyl group and at least one silicon-bonded alkenyl group in a molecule; and methyl polysilicate, ethyl polysilicate, and epoxy group-containing ethyl polysilicate.
Furthermore, the present composition may contain a phosphor that is used to obtain light of a desired wavelength by converting the wavelength of light emitted from a light emitting element that is encapsulated or covered with the cured product of the present composition. Examples of such a phosphor include yellow, red, green, and blue light emitting phosphors formed from oxide phosphors, oxynitride phosphors, nitride phosphors, sulfide phosphors, and oxysulfide phosphors, which are widely used in light emitting diodes (LEDs). Examples of the oxide-based phosphors include yttrium, aluminum, and garnet-type YAG green to yellow light-emitting phosphors containing cerium ions; terbium, aluminum, and garnet-type TAG yellow light-emitting phosphors containing cerium ions; and silicate green to yellow light-emitting phosphors containing cerium or europium ions. Examples of the oxynitride-based phosphors include silicon, aluminum, oxygen, and nitrogen-type SiALON red to green light-emitting phosphors containing europium ions. Examples of the nitride-based phosphors include calcium, strontium, aluminum, silicon, and nitrogen-type CASN red light-emitting phosphors containing europium ions. Examples of the sulfide-based phosphors include ZnS green light-emitting phosphors containing copper ions or aluminum ions. Examples of the oxysulfide-based phosphors include Y2O2S red light-emitting phosphors containing europium ions. One type of these phosphors or a mixture of two or more types of these phosphors may be used. The content of the phosphor is in a range of 0.1 to 70 mass %, and preferably in a range of 1 to 20 mass %, relative to the total amount of the components (A) to (D).
Moreover, an inorganic filler such as silica, glass, alumina or zinc oxide; an organic resin fine powder of a polymethacrylate resin and the like; a heat-resistant agent, a dye, a pigment, a flame retardant, a solvent and the like may be incorporated as optional components in the present composition at levels that do not impair the object of the present invention.
In order to sufficiently suppress the discoloration of silver electrodes or silver plating of a substrate in an optical semiconductor device due to sulfur-containing gas in the air, at least one type of a fine powder having an average particle diameter of 0.1 nm to 5 μm, which is selected from the group consisting of zinc oxide fine powders surface-coated with at least one type of oxide of an element selected from the group consisting of Al, Ag, Cu, Fe, Sb, Si, Sn, Ti, Zr, and rare earth elements, zinc oxide fine powders surface-treated with organosilicon compounds having no alkenyl groups, and hydrate fine powders of zinc carbonate, may be contained.
In a zinc oxide fine powder surface-coated with an oxide, examples of the rare earth elements include yttrium, cerium, and europium. Examples of the oxide on the surface of the zinc oxide fine powder include Al2O3, AgO, Ag2O, Ag2O3, CuO, Cu2O, FeO, Fe2O3, Fe3O4, Sb2O3, SiO2, SnO2, Ti2O3, TiO2, Ti3O5, ZrO2, Y2O3, CeO2, Eu2O3, and mixtures of two or more types of these oxides.
In a zinc oxide fine powder surface-treated with an organic silicon compound, the organic silicon compound does not have alkenyl groups, and examples thereof include organosilanes, organosilazanes, polymethylsiloxanes, organohydrogenpolysiloxanes, and organosiloxane oligomers. Specific examples include organochlorosilanes, such as trimethylchlorosilane, dimethylchlorosilane, and methyltrichlorosilane; organotrialkoxysilanes, such as methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; diorganodialkoxysilanes, such as dimethyldimethoxysilane, dimethyldiethoxysilane, and diphenyldimethoxysilane; triorganoalkoxysilanes, such as trimethylmethoxysilane and trimethylethoxysilane; partial condensates of these organoalkoxysilanes; organosilazanes, such as hexamethyldisilazane; a polymethylsiloxane, an organohydrogenpolysiloxane, an organosiloxane oligomer having a silanol group or an alkoxy group, and silanol group- or alkoxy group-containing resin-like organopolysiloxanes comprising an R2SiO3/2 unit (wherein, R2 is a monovalent hydrocarbon group that is not an alkenyl group and that is exemplified by alkyl groups, such as a methyl group, an ethyl group, and a propyl group, and aryl groups, such as a phenyl group), and/or an SiO4/2 unit.
In addition, the composition may also contain a triazole-based compound as an optional component in order to enable the further suppression of the discoloration of the silver electrodes or the silver plating of the substrate due to a sulfur-containing gas in the air. Specific examples thereof include 1H-1,2,3-triazole, 2H-1,2,3-triazole, 1H-1,2,4-triazole, 4H-1,2,4-triazole, 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 1H-1,2,3-triazole, 2H-1,2,3-triazole, 1H-1,2,4-triazole, 4H-1,2,4-triazole, benzotriazole, tolyltriazole, carboxybenzotriazole, 1H-benzotriazole-5-methylcarboxylate, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, 5-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, chlorobenzotriazole, nitrobenzotriazole, aminobenzotriazole, cyclohexano[1,2-d]triazole, 4,5,6,7-tetrahydroxytolyltriazole, 1-hydroxybenzotriazole, ethylbenzotriazole, naphthotriazole, 1-N,N-bis(2-ethylhexyl)-[(1,2,4-triazol-1-yl)methyl]amine, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]tolyltriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]carboxybenzotriazole, 1-[N,N-bis(2-hydroxyethyl)-aminomethyl]benzotriazole, 1-[N,N-bis(2-hydroxyethyl)-aminomethyl]tolyltriazole, 1-[N,N-bis(2-hydroxyethyl)-aminomethyl]carboxybenzotriazole, 1-[N,N-bis(2-hydroxypropyl)amino methyl]carboxybenzotriazole, 1-[N,N-bis(1-butyl)aminomethyl]carboxybenzotriazole, 1-[N,N-bis(1-octyl)aminomethyl]carboxybenzotriazole, 1-(2′,3′-di-hydroxypropyl)benzotriazole, 1-(2′,3′-di-carboxyethyl)benzotriazole, 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)benzotriazole, 2-(2′-hydroxy-3′,5′-aminophenyl)benzotriazole, 2-(2′-hydroxy-4′-octoxyphenyl)benzotriazole, 2-(2′-hydroxy-5′-tert-butylphenyl)benzotriazole, 1-hydroxybenzotriazole-6-carboxylic acid, 1-oleoylbenzotriazole, 1,2,4-triazol-3-ol, 5-amino-3-mercapto-1,2,4-triazole, 5-amino-1,2,4-triazole-3-carboxylic acid, 1,2,4-triazole-3-carboxyamide, 4-aminourazole, and 1,2,4-triazol-5-one. The content of the triazole-based compound is not particularly limited; however, the content is, in terms of a mass unit, in a range of 0.01 ppm to 3%, and preferably in a range of 0.1 ppm to 1%, relative to the amount of the present composition.
The present composition may further contain a cerium-containing organopolysiloxane as an optional component to suppress cracking due to heat aging of the resulting cured product. The cerium-containing organopolysiloxane can be prepared by, for example, a reaction between cerium chloride or a ceric salt of carboxylic acid and an alkali metal salt of silanol group-containing organopolysiloxane.
Examples of the ceric salt of carboxylic acid include cerium 2-ethylhexanoate, cerium naphthenate, cerium oleate, cerium laurate, and cerium stearate.
Furthermore, examples of the alkali metal salt of silanol group-containing organopolysiloxane include potassium salts of diorganopolysiloxane capped at both molecular terminals with silanol groups, sodium salts of diorganopolysiloxane capped at both molecular terminals with silanol groups, potassium salts of diorganopolysiloxane capped at one molecular terminal with a silanol group and the other molecular terminal with triorganosiloxy group, and sodium salts of diorganopolysiloxane capped at one molecular terminal with a silanol group and the other molecular terminal with triorganosiloxy group. Note that examples of the group to be bonded to the silicon atom in this organopolysiloxane include alkyl groups having from 1 to 12 carbons, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group; aryl groups having from 6 to 20 carbons, such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group; aralkyl groups having from 7 to 20 carbons, such as a benzyl group, a phenethyl group, and a phenylpropyl group; and groups in which some or all of the hydrogen atoms in these groups are substituted with halogen atoms, such as fluorine atoms, chlorine atoms, and bromine atoms.
The reaction described above is performed at room temperature or by heating in an organic solvent including alcohols, such as methanol, ethanol, isopropanol, and butanol; aromatic hydrocarbons, such as toluene and xylene; aliphatic hydrocarbons, such as hexane and heptane; mineral spirit, ligroin, petroleum ether, and the like. Furthermore, the resulting reaction product is preferably subjected to removal of organic solvents and/or low boiling point components by distillation and/or removal of precipitates by filtration, as necessary. Furthermore, to accelerate this reaction, dialkylformamide, hexaalkylphosphoramide, or the like may be added. The content of the cerium atom in the cerium-containing organopolysiloxane prepared as described above is preferably in a range of 0.1 to 5 mass %.
Although the content of the cerium-containing organopolysiloxane is not limited, the content is preferably an amount by which the content of the cerium atom, in terms of a mass unit, is in a range of 10 to 2,000 ppm, 20 to 2,000 ppm, 20 to 1,000 ppm, or 20 to 500 ppm, relative to the amount of the present composition. This is because, when the content of the cerium-containing organopolysiloxane is greater than or equal to the lower limit of the range described above, heat resistance of the resulting composition can be enhanced, and on the other hand, when the content is less than or equal to the upper limit of the range described above, variation in luminescent chromaticity can be decreased when the composition is used in an optical semiconductor device.
The curing of the present composition proceeds either at room temperature or under heating, but it is preferable to heat the composition in order to achieve rapid curing. The heating temperature is preferably in a range of 50 to 200° C.
The semiconductor device of the present invention will now be described in detail.
The semiconductor device of the present invention is produced by encapsulating a semiconductor element with a cured product of the curable silicone composition described above. Examples of such a semiconductor device of the present invention include a light emitting diode (LED), a photocoupler, and a charge coupled device (CCD). Examples of the semiconductor element include a light emitting diode (LED) chip and a solid-state image sensing device.
An example of a method for producing the surface mounted type LED illustrated in
The adhesion promoter, the curable silicone composition, and the semiconductor device of the present invention will be described in detail using examples. Note that, in the formulas, Me represents a methyl group, Vi represents a vinyl group, and Ph represents a phenyl group.
First, 400 g (2.02 mol) of phenyltrimethoxysilane and 93.5 g (0.30 mol) of 1,3-divinyl-1,3-diphenyldimethyldisiloxane were loaded into a reaction vessel and mixed in advance. Next, 1.74 g (11.6 mmol) of trifluoromethane sulfonic acid was added, and 110 g (6.1 mol) of water was added and heat-refluxed for 2 hours while stirring. Next, the mixture was distilled at atmospheric pressure by heating until the temperature reached 85° C. Next, 89 g of toluene and 1.18 g (21.1 mmol) of potassium hydroxide were added, and the mixture was distilled at atmospheric pressure by heating until the reaction temperature reached 120° C. and then allowed to react at this temperature for 6 hours. The mixture was then cooled to room temperature, and the cooled mixture was neutralized by adding 0.68 g (11.4 mmol) of acetic acid. After filtering off the formed salts, low boiling point substances were removed from the obtained transparent solution by heating under reduced pressure to prepare 347 g (yield: 98%) of an organopolysiloxane resin represented by the average unit formula:
(McPhViSiO1/2)0.23(PhSiO3/2)0.77.
In a reaction vessel, 18.8 g (0.075 mol) of triallylisocyanurate, a catalytic amount of a toluene solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex were charged and heated at 80 to 90° C. Thereafter, 18.6 g (0.075 mol) of disiloxane represented by the formula:
was added dropwise and, after the completion of the addition, reacted at 100° C. for 2 hours. After absence of the silicon atom-bonded hydrogen atoms in the reaction mixture was confirmed using an infrared spectrophotometer, low boiling point components were removed under reduced pressure to obtain a light yellow liquid. As a result of NMR analysis, it was found that this liquid was an adhesion promoter represented by the average formula.
In a reaction vessel, 18.8 g (0.075 mol) of triallylisocyanurate, a catalytic amount of a toluene solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex were charged and heated at 80 to 90° C. Thereafter, 28.0 g (0.1125 mol) of disiloxane represented by the formula:
was added dropwise and, after the completion of the addition, reacted at 100° C. for 2 hours. After absence of the silicon atom-bonded hydrogen atoms in the reaction mixture was confirmed using an infrared spectrophotometer, low boiling point components were removed under reduced pressure to obtain a light yellow liquid. As a result of NMR analysis, it was found that this liquid was an adhesion promoter represented by the average formula:
The curable silicone compositions shown in Table 1 were prepared using the components described below. Moreover, in Table 1, the content of component (D) is expressed in terms of the content (ppm; in terms of a mass unit) of platinum metal relative to the amount of the curable silicone composition. Furthermore, SiH/Vi in Table 1 shows the number of moles of silicon atom-bonded hydrogen atom in component (B) per 1 mol total of alkenyl groups contained in components (A) and (C).
The following components were used as component (A).
Component (A-1): an organopolysiloxane represented by the average unit formula:
(Me2ViSiO1/2)0.2(PhSiO3/2)0.8
Component (A-2): a methylphenylpolysiloxane capped at both molecular terminals with dimethylvinylsiloxy groups having a viscosity of 3,000 mPa·s
The following components were used as component (B).
Component (B-1): an organotrisiloxane represented by the formula:
HMe2SiOPh2SiOSiMe2H
The following components were used as component (C).
Component (C-1): an adhesion promoter prepared in Example 1
Component (C-2): an adhesion promoter prepared in Example 2
Component (C-3): an adhesion promoter which is formed from a condensation reaction product of a methylvinylsiloxane oligomer capped at both molecular terminals with silanol groups and having a viscosity at 25° C. of 30 mPa·s, and 3-glycidoxypropyl trimethoxysilane
The following components were used as component (D).
Component (D-1): a solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (the solution contains 0.1 mass % of platinum)
Adhesion of the cured product of the curable silicone composition was evaluated as follows.
A spacer that was made of a fluoro resin and had a thickness of 2 mm and a hole having a diameter of 5 mm was placed on an aluminum plate or a silver-plated panel for adhesion test. The curable silicone composition was charged into the hole of the spacer and then left in a circulating hot air oven at 150° C. for 1 hour to form a cylindrical cured product having a diameter of 5 mm and a height of 2 mm. This cured product was then peeled off at a rate of 50 mm/min using a die shear strength measurement device, and the load (MPa) at this time was measured to evaluate the adhesion.
The curable silicone composition was used to produce a surface-mounted type light emitting diode (LED) as described below.
In a cylindrical frame 5 that was made from polyphthalamide (PPA) resin and that had a closed bottom (inner diameter: 2.0 mm; depth: 1.0 mm), lead frames 2 and 3 were extended from side walls of the frame 5 toward the center of inner bottom of the frame 5. An LED chip 1 was mounted on the center of the lead frame 2, and the LED chip 1 and the lead frame 3 were electrically connected by a bonding wire 4 in an unencapsulated light emitting diode. To the unencapsulated light emitting diode, the curable silicone composition that had been degassed was injected using a dispenser. Thereafter, the light emitting diode illustrated in
Sixteen light emitting diodes produced by the method described above were immersed in commercially available red ink and left at 50° C. for 24 hours. After the light emitting diodes were left, presence or absence of permeation of the red ink were observed using a microscope and evaluated as follows.
⊚: Permeation of the ink was observed in two or less light emitting diodes.
Δ: Permeation of the ink was observed in three to eight light emitting diodes.
x: Permeation of the ink was observed in nine or more light emitting diodes.
Sixteen light emitting diodes produced by the method described above were subjected to 1,000 cycles of heat cycle test, in which 1 cycle thereof was a cycle of −40° C. for 30 minutes and then 125° C. for 30 minutes. Thereafter, lighting test of light emitting diodes was performed by turning on the electricity and evaluated as follows.
⊚: Fourteen or more light emitting diodes were lighted up.
o: Eight to thirteen light emitting diodes were lighted up.
Δ: Seven or less light emitting diodes were lighted up.
The curable silicone compositions shown in Table 2 were prepared using the components described below. Note that, in Table 2, the content of component (D) is expressed in terms of the content (ppm; in terms of a mass unit) of platinum metal relative to the amount of the curable silicone composition. Furthermore, SiH/Vi in Table 2 shows the number of moles of silicon atom-bonded hydrogen atom in component (B) per 1 mol total of alkenyl groups contained in components (A) and (C).
The following components were used as component (A). Furthermore, the viscosity was the value at 25° C. and was measured using a type B viscometer in accordance with JIS K 7117-1. Furthermore, the content of the vinyl group was measured by analysis using FT-IR, NMR, GPC, and the like.
Component (A-3): a dimethylpolysiloxane capped at both molecular terminals with dimethylvinylsiloxy groups (vinyl group content=0.48 mass %) that has a viscosity of 300 mPa·s and that is represented by the average formula:
Me2ViSiO(Me2SiO)150SiMe2Vi
Component (A-4): a dimethylpolysiloxane capped at both molecular terminals with dimethylvinylsiloxy groups (vinyl group content=0.15 mass %) that has a viscosity of 10,000 mPa·s and that is represented by the average formula:
Me2ViSiO(Me2SiO)500SiMe2Vi
Component (A-5): an organopolysiloxane resin having two or more vinyl groups in a molecule (vinyl group content=5.4 mass %) that is a white solid at 25° C. and soluble in toluene and that is represented by the average unit formula:
(Me2ViSiO1/2)0.15(Me3SiO1/2)0.47(SiO4/2)0.38(HO1/2)0.0001
Component (A-6): an organopolysiloxane having two or more vinyl groups in a molecule (vinyl group content=4.2 mass %) that is a white solid at 25° C. and soluble in toluene and that is represented by the average unit formula:
(Me2ViSiO1/2)0.15(Me3SiO1/2)0.38(SiO4/2)0.47(HO1/2)0.01
As component (B), the following component was used.
Component (B-2): a polymethylhydrogensiloxane capped at both molecular terminals with trimethylsiloxy groups (silicon atom-bonded hydrogen atom content=1.6 mass %) that has a viscosity of 20 mPa·s and that is represented by the average formula:
Me3SiO(MeHSiO)55SiMe3
As component (C), components (C-1) and (C-3) described above were used.
The following components were used as component (D).
Component (D-2): a solution of a platinum-1,3-divinyltetramethyldisiloxane complex in 1,3-divinyltetramethyldisiloxane (platinum metal content=approximately 5,000 ppm).
The following component was used as component (E).
Component (E-1): 1-ethynylcyclohexan-1-ol
The curable silicone composition was used to produce a surface-mounted type light emitting diode (LED) as described below.
In a cylindrical frame 5 that was made from polyphthalamide (PPA) resin and that had a closed bottom (inner diameter: 2.0 mm; depth: 1.0 mm), lead frames 2 and 3 were extended from side walls of the frame 5 toward the center of inner bottom of the frame 5. An LED chip 1 was mounted on the center of the lead frame 2, and the LED chip 1 and the lead frame 3 were electrically connected by a bonding wire 4 in an unencapsulated light emitting diode. To the unencapsulated light emitting diode, the curable silicone composition that had been degassed was injected using a dispenser. Thereafter, the light emitting diode illustrated in
For eight light emitting diodes produced by the method described above, peeling conditions between the lead frames 2 and 3 and the bonding wire 4 and the cured product 6 were observed using an optical microscope. The proportion of the number of the light emitting diode in which peeling was observed is shown in Table 2.
Peeling Proportion 1 after Moisture Absorption Reflow
For eight light emitting diodes produced by the method described above, peeling conditions between the lead frames 2 and 3 and the bonding wire 4, and the cured product 6 were observed using an optical microscope after the light emitting diodes were placed in a constant-temperature and constant-humidity chamber at 85° C. and 85% for 24 hours, then placed in an oven at 280° C. for 30 seconds, and placed at room temperature (25° C.). The proportion of the number of the light emitting diode in which peeling was observed is shown in Table 2.
Peeling Proportion 2 after Moisture Absorption Reflow
For eight light emitting diodes produced by the method described above, peeling conditions between the lead frames 2 and 3 and the bonding wire 4 and the cured product 6 were observed using an optical microscope after the light emitting diodes were placed in a constant-temperature and constant-humidity chamber at 85° C. and 85% for 72 hours, then placed in an oven at 280° C. for 30 seconds, and placed at room temperature (25° C.). The proportion of the number of the light emitting diode in which peeling was observed is shown in Table 2.
From the results shown in Table 2, it is clear that the cured product of the curable silicone composition of Example 7 exhibited a higher peeling resistance compared to that of the cured product of the curable silicone composition of Comparative Example 3.
The curable silicone composition of the present invention is a composition that has excellent flowability and which is cured to form a cured product in which phosphors are homogeneously dispersed and that has a high refractive index, and is therefore suitable for use as a sealing agent or coating agent for light emitting elements in optical semiconductor devices such as light emitting diodes (LEDs).
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-115578 | Jun 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/002717 | 5/29/2015 | WO | 00 |
