JP2010003848A - Light emitting device - Google Patents

Abstract

In a light-emitting device in which a light-emitting element is bonded and fixed to a support substrate by a die attach layer and has bonding wire bonding on the light-emitting element, the bonding wire can be firmly bonded to the light-emitting element, and the die can be used for a long period of use. Provided is a light emitting device having a die attach layer in which the light emission luminance of the light emitting device is less reduced due to deterioration of the touch material.
A light emitting device of the present invention connects a support substrate, an electrode terminal, a light emitting chip, a die attach layer for bonding and fixing the light emitting chip on the support substrate, and connecting the electrode terminal and the light emitting chip. A light emitting device including a bonding wire and a sealing layer formed so as to seal the light emitting chip, wherein the die attach layer is made of polyorganosiloxane containing and dispersing spherical silicone fine particles.
[Selection] Figure 1

Description

  The present invention relates to a light-emitting device, and more particularly, a light-emitting element such as a light-emitting diode (LED) is bonded and fixed to a support substrate with polyorganosiloxane, has excellent wire bonding properties, and emits light with a long-term use. The present invention relates to a light-emitting device that is excellent in reliability with little deterioration.

  In a light emitting device such as a light emitting diode (LED) lamp or a photocoupler, a light emitting element (for example, an LED chip) is bonded onto a support substrate by a die attach layer made of a highly transparent adhesive such as epoxy resin or silicone resin. A device having a configuration in which electrode terminals provided on a supporting substrate and the like and light emitting elements are connected by bonding wires has been conventionally used (for example, see Patent Document 1).

  In the light emitting device having such a configuration, with the increase in output of the LED chip, the conventional die attach layer made of epoxy resin causes yellowing, cracking, etc. due to heat and light, resulting in a decrease in light emission luminance. There was a problem in terms of reliability during use. In addition, if the die attach layer is formed using a silicone resin with excellent heat resistance, it is possible to prevent a decrease in light emission luminance due to long-term use, but the bonding strength between the bonding wire and the light emitting element is not sufficient. There was a problem. This is because ultrasonic vibration is used when bonding a bonding wire to the light emitting element on the die attach layer, but since the elastic modulus is low in the existing die attach layer made of silicone resin, light is emitted in the bonding step. As a result of the sinking of the element into the die attach layer or the like and insufficient support of the light emitting element, bonding wire bonding having sufficient strength to the light emitting element cannot be obtained.

Therefore, as a die attach layer for adhering and fixing the light emitting element to the support substrate of the light emitting apparatus, it is possible to firmly bond the bonding wire to the light emitting element, and the light emitting apparatus is caused by deterioration of the die attach layer in the long term use There has been a demand for a die attach material in which the decrease in light emission luminance is small.
JP 2007-324256 A

  The present invention provides a light-emitting device in which a light-emitting element is bonded and fixed to a support substrate by a die attach layer and has a bonding wire bonding on the light-emitting element. It is an object of the present invention to provide a light emitting device having a die attach layer in which a decrease in light emission luminance of the light emitting device due to deterioration of the die attach layer is small.

  The light emitting device of the present invention includes a support substrate, an electrode terminal, a light emitting chip, a die attach layer for bonding and fixing the light emitting chip on the support substrate, a bonding wire for connecting the electrode terminal and the light emitting chip, A light emitting device comprising a sealing layer formed to seal the light emitting chip, wherein the die attach layer is mainly composed of polyorganosiloxane, and spherical silicone fine particles are contained in the polyorganosiloxane. -It is characterized by being distributed.

  According to the present invention, the die attach layer for fixing the light emitting element is configured to contain and disperse the spherical silicone fine particles in the silicone resin, so that the spherical silicone fine particles serve as a spacer in the die attach layer. -The sedimentation of the light emitting element to the die attach layer during bonding wire bonding is prevented, and the bonding between the light emitting element and the bonding wire can be strengthened.

  Furthermore, the light emitting device according to the present invention can be used stably for a long time without causing a decrease in light emission luminance due to deterioration of the die attach material because the material constituting the die attach layer is excellent in heat resistance and UV resistance. It is. Further, by containing and dispersing spherical silicone fine particles in the die attach material, an effect of scattering light incident on the die attach layer can be obtained, and it can be expected to contribute to the improvement of the light emission luminance of the entire light emitting device.

Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments.
As shown in FIG. 1, an LED lamp 10 which is an embodiment of a light emitting device of the present invention includes a concave support substrate 1, an electrode terminal 6 provided on the inner bottom surface of the recess of the support substrate 1, and an LED chip 2. A die attach layer 3 for bonding and fixing the LED chip 2 on the bottom surface of the concave portion of the support substrate 1, a bonding wire 7 for connecting the electrode terminal 6 and the LED chip 2, and an LED including the bonding wire 7. And a sealing layer 5 disposed so as to seal the periphery of the chip 2. Further, an optical lens layer (not shown) made of, for example, silicone rubber may be disposed on the sealing layer 5.

  The support substrate 1 is formed of, for example, polyphthalamide (PPA), glass fiber reinforced PPA, ceramics, and the like. On the support substrate 1, silver (Ag), gold (Au), and aluminum (Al ) And the like (not shown) are formed in a desired shape by an ordinary method. In the LED lamp 10 shown in FIG. 1, the LED chip 2 is directly bonded and fixed on the support substrate 1 via the die attach layer 3, but the lead formed on the support substrate 1 depending on the shape of the lead electrode. The LED chip 2 may be bonded and fixed on the electrode via the die attach layer 3. Moreover, although the structure which connects the LED chip 2 and the electrode terminal 6 with the bonding wire 7 exists in two places in FIG. 1, depending on the structure of a light-emitting device, it may be one place.

  Further, FIG. 2 shows an LED lamp 20 which is another embodiment of the light emitting device of the present invention. In the LED lamp 20, one lead frame (lead electrode) 8 having a support substrate 1 and electrode terminals 6 is integrated. The other lead frame (lead electrode) 8 having the electrode terminal 6 is provided independently. In this case, the LED chip 2 is bonded and fixed via a die attach layer 3 on a support substrate 1 made of a conductive material such as a metal constituting a general lead frame. Also in the LED lamp 20, the LED chip 2 and the electrode terminal 6 are connected by the bonding wire 7, and the LED chip 2 is sealed by the sealing layer 5 including the internal resin layer 28 and the external resin layer 29.

  The die attach layer 3 for adhering and fixing the LED chip 2 on the support substrate 1 is mainly composed of a polyorganosiloxane 3a, and spherical silicone fine particles 3b are contained and dispersed in the polyorganosiloxane 3a.

  The polyorganosiloxane (silicone) constituting the die attach layer 3 is formed by heating and curing the addition reaction curable polyorganosiloxane composition at room temperature or at a temperature of 50 to 200 ° C. Examples of the addition reaction curable polyorganosiloxane composition include (a) a polyorganosiloxane having an alkenyl group bonded to an average of 0.5 or more silicon atoms in one molecule, and (b) an average in one molecule. A polyorganohydrogensiloxane having a hydrogen atom bonded to two or more silicon atoms is used in such a manner that the silicon-bonded hydrogen atom in this component is 0.1 per mol of the silicon-bonded alkenyl group in the component (a). Those containing an amount of ~ 5.0 mol and (c) a catalytic amount of a platinum-based catalyst can be used.

  The component (a) is a base polymer, which is a polyorganosiloxane having an average of 0.5 or more, more preferably 2 or more, alkenyl groups bonded to silicon atoms in one molecule. When the average number of alkenyl groups in one molecule is less than 0.5, the resulting composition may not be sufficiently cured. The molecular structure is not particularly limited, and may be linear, branched or cyclic, or a mixture thereof. From the viewpoint of mechanical strength of the cured product, a linear structure is preferable.

  Examples of the alkenyl group bonded to the silicon atom include a vinyl group, an allyl group, a 1-butenyl group, and a 1-hexenyl group, but a vinyl group is most preferable from the viewpoint of ease of synthesis. These alkenyl groups may be present in either the terminal part or the intermediate part of the molecular chain of the polyorganosiloxane, or may be present in both of them, in order to impart excellent mechanical properties to the cured product. Is preferably present at least at the end.

  Examples of the organic group other than the alkenyl group bonded to the silicon atom include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and a dodecyl group; an aryl group such as a phenyl group; a 2-phenylethyl group, 2 -Aralkyl groups such as phenylpropyl group; substituted hydrocarbon groups such as chloromethyl group and 3,3,3-trifluoropropyl group, etc. are exemplified. From the viewpoint of ease of synthesis, a methyl group or a phenyl group is preferable.

  The viscosity of the alkenyl group-containing polyorganosiloxane as component (a) is not particularly limited, but the viscosity at 23 ° C. is preferably in the range of 5 to 100,000 mPa · s. When the viscosity at 23 ° C. is less than 5 mPa · s, physical properties tend to be lowered. On the other hand, when the viscosity exceeds 100,000 mPa · s, the handling workability of the composition is lowered, which is not preferable. In addition, when (a) component is a mixture, it is preferable that it is in the said range as a viscosity of a mixture instead of the viscosity of each component.

  The polyorganohydrogensiloxane having a hydrogen atom bonded to two or more silicon atoms on average in one molecule as the component (b) is a component that serves as a crosslinking agent for the component (a). Examples of the organic group other than the hydrogen atom bonded to the silicon atom include the same groups as those other than the alkenyl group in the aforementioned component (a). A methyl group is most preferred because of ease of synthesis. The polyorganohydrogensiloxane may be linear, branched or cyclic.

  The compounding amount of the polyorganohydrogensiloxane as component (b) is 1 mol of silicon atom-bonded alkenyl group (for example, vinyl group) as component (a), Si—H group) is 0.1 to 5.0 mol, more preferably 0.5 to 2.0 mol. If the amount is less than 0.1 mol, the resulting composition may not be sufficiently cured. On the other hand, when it exceeds 5.0 mol, the cured product becomes too hard. In addition, unreacted Si—H groups remain in the cured composition, and the physical properties and heat resistance of the cured product deteriorate with time.

  The platinum-based catalyst as the component (c) is a catalyst that promotes an addition reaction (hydrosilylation reaction) between the alkenyl group of the component (a) and the Si—H group of the component (b). Examples of the platinum catalyst (c) include platinum alone, chloroplatinic acid, platinum-olefin complexes, platinum-vinylsiloxane complexes, platinum-phosphorus complexes, platinum-alcohol complexes, and platinum black. The amount of the platinum-based catalyst is 0.01 to 2000 ppm, preferably 1 to 200 ppm by weight in terms of platinum atoms with respect to the alkenyl group-containing polyorganosiloxane (a). If the content is less than 0.01 ppm, curing does not proceed sufficiently. On the other hand, even if it exceeds 2000 ppm, no improvement in the curing rate can be expected.

  The addition reaction curable polyorganosiloxane composition for forming the die attach layer 3 contains the components (a) to (c) described above, but as other components, a reaction inhibitor (curing retarder) is used. You may contain. Examples of the reaction inhibitor include 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, and 2-phenyl-3-butyne. Alkyne alcohols such as 2-ol; Enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; 1,3,5,7-tetramethyl- Examples include 1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, benzotriazole, diallyl maleate, and the like. It is preferable that a compounding quantity shall be 0.001-5 weight part with respect to 100 weight part of (a) component.

  The polyorganosiloxane composition may optionally contain a component for imparting adhesiveness to the composition. Examples of the component for imparting adhesiveness include epoxy functional group-containing alkoxysilanes such as γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and vinyltrimethoxy. Alkenyl group-containing alkoxysilanes such as silane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropyltri Amino group-containing alkoxysilanes such as methoxysilane, N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-acrylic Roxypropi Examples include alkoxy silanes such as acrylic or methacrylic group-containing alkoxysilanes such as rutrimethoxysilane, and mercapto group-containing alkoxysilanes such as mercaptopropyltrimethoxysilane. In addition, examples of the organosiloxane oligomer include the following compounds.

  The amount of the adhesion-imparting component is 0.3 to 20 parts by weight, preferably 0.3 to 10 parts by weight per 100 parts by weight of component (a). If the blending amount is less than 0.3 parts by weight, sufficient adhesion cannot be obtained. On the other hand, exceeding 20 parts by weight is uneconomical in terms of cost.

In such a polyorganosiloxane composition, a filler component, a phosphor component and the like may be further blended as optional components according to various purposes. Examples of the filler include inorganic powders such as silica and alumina, and metal powders such as silver (Ag) and aluminum (Al). Among these, silica, particularly fumed silica (fumed silica). Fine silica such as calcined silica and precipitated silica is preferably used for the purpose of increasing the adhesive strength of the polyorganosiloxane composition. The particle diameter of the fine particle silica to be blended is preferably 1 nm to 100 μm, more preferably 5 nm to 50 μm in terms of average particle diameter. The amount is preferably 0.1 to 50% by weight, more preferably 1 to 20% by weight, based on the total amount of the composition. If the blending amount is less than 0.1% by weight, sufficient adhesive strength may not be obtained, and if it exceeds 50% by weight, the light emission luminance of the light emitting device may be lowered.
Moreover, as a fluorescent substance component, the fluorescent substance component generally used for a light emitting element can be used.

  As the spherical silicone fine particles 3b that the die attach layer 3 contains and disperses in the main polyorganosiloxane (silicone) 3a, for example, fine particles made of polyorganosilsesquioxane can be used. Polyorganosilsesquioxane fine particles are finely cross-linked silicone resin fine particles having a three-dimensional network structure by siloxane bonds, and are excellent in solvent resistance that do not swell or dissolve in an organic solvent.

The polyorganosilsesquioxane that makes up the fine particles
General formula: R ¹ Si (OR ² ) ₃ (1)
(Wherein R ¹ represents a monovalent group selected from a substituted or unsubstituted alkyl group, an alkenyl group and a phenyl group, and R ² represents a substituted or unsubstituted alkyl group which is the same or different from each other). Spherical silicone fine particles produced using one or more of organotrialkoxysilanes as a raw material and / or general formula: SiY ₄ (2)
(Wherein Y represents the same or different hydrolyzable groups) and one or more of organotrialkoxysilanes represented by the above general formula (1) are produced as raw materials. Spherical silicone fine particles.

Among these polyorganosilsesquioxanes, the organic group R ¹ bonded to the silicon atom is preferably a methyl group from the viewpoint of ease of production and availability. In addition, various modified polyorganosilsesquioxane fine particles can be used as long as the effects of the present invention are not impaired.

The polyorganosilsesquioxane fine particles used in the embodiment preferably have an average particle size of 0.1 to 100 μm, more preferably 1 to 10 μm. If the average particle size is less than 0.1 μm, the bonding strength of the bonding wire to the light emitting element may not be sufficient, and if it exceeds 100 μm, depending on the thickness of the die attach layer required for the light emitting device to be used, its homogeneity It may be a problem in terms of thickness management. Therefore, the average particle size of the polyorganosilsesquioxane fine particles used in the present invention is preferably adjusted to about 50% or less in consideration of the thickness of the light emitting device die attach layer used.
Further, from the viewpoint of homogenizing the dispersion of light incident on the die attach layer 3, it is preferable that the variation in particle diameter is small. Furthermore, the shape of the polyorganosilsesquioxane fine particles is preferably a spherical shape that is independent from a practical aspect, and more preferably a true spherical shape. Such polyorganosilsesquioxane fine particles are described in, for example, JP-A 63-101857, JP-A 63-77940, JP-A 2000-186148, JP-A 2001-192452. It can be manufactured by a method.

  The content of the spherical silicone fine particles such as the polyorganosilsesquioxane fine particles is preferably 0.1 to 50% by weight, preferably 1 to 20% by weight with respect to the polyorganosiloxane as the base component. It is more preferable to set the ratio. When the content is less than 0.1% by weight, the effect of improving the wire bonding property due to the blending of the spherical silicone fine particles may not be sufficiently exhibited. On the other hand, if the content of the spherical silicone fine particles exceeds 50% by weight, the emission luminance of the light emitting device may be lowered, which is not preferable.

  In the die attach layer 3 of the embodiment, spherical silicone fine particles are further added to the addition reaction curable polyorganosiloxane (silicone) composition obtained by mixing the components (a) to (c) and optional additive components. The composition, which has been added and sufficiently stirred and mixed, is applied to the support substrate 1 provided with the electrode terminals 6 by a usual method such as potting to form a composition layer, and after defoaming, the composition It is formed by installing and curing the LED chip 2 on the layer. Curing proceeds at room temperature or by heating, but in order to cure quickly, it is preferable to heat to a temperature of 50 to 200 ° C. Although the thickness of the die attach layer 3 depends on the LED chip 2 to be used, it is generally adjusted to about 1 to 100 μm, and preferably to about 5 to 30 μm.

  After the LED chip 2 is adhered and fixed on the support substrate 1 by the die attach layer 3 in this way, the LED chip 2 and the electrode terminal 6 of the lead electrode provided on the support substrate 1 are made of gold (Au). They are connected by bonding wires 7 having the same configuration as that used in ordinary light emitting devices such as wires. Actually, the bonding between the LED chip 2 and the bonding wire 7 is the bonding between the electrode terminal (not shown) on the LED chip 2 and the bonding wire 7. As a method of bonding the bonding wire 7 to the electrode terminal on the LED chip 2 and the lead electrode electrode terminal 6, bonding is performed by a normal method, for example, an ultrasonic welding method using ultrasonic vibration or the like by a normal apparatus and conditions. Methods and the like. In the LED lamp 20 having the electrode terminal 6 installed on the lead frame 8 independent of the support substrate 1 as in the embodiment shown in FIG.

  In the LED lamp 10 of the embodiment of the present invention shown in FIG. 1, the sealing layer 5 that seals the LED chip 2 includes the LED chip 2, the bonding wire 7, and the electrode terminal connected by the LED chip 2 and the bonding wire 7. 6 is filled in the concave portion of the support substrate 1 so as to seal, and the upper surface is formed so as to have a dome shape. The sealing layer 5 is usually formed of a highly transparent resin such as a silicone resin or an epoxy resin, but is preferably formed of a silicone resin from the viewpoint of heat resistance and UV resistance. The sealing layer 5 can further contain a phosphor as necessary.

  In the LED lamp 20 of the embodiment of the present invention shown in FIG. 2, the sealing layer 5 that seals the LED chip 2 is composed of an inner resin layer 28 and an outer resin layer 29, and both the resin layers are usually silicone resin. The resin is formed of a highly transparent resin such as an epoxy resin, but is preferably formed of a silicone resin from the viewpoint of heat resistance and UV resistance. The sealing layer 5 can further contain a phosphor as necessary.

  In the LED lamp according to the embodiment of the present invention, the die attach layer 3 for adhering / fixing the LED chip 2 to the support substrate 1 contains a polysiloxane containing spherical silicone fine particles 3b such as polyorganosilsesquioxane fine particles. It is comprised by the organosiloxane 3a composition. By adopting such a configuration, the spherical silicone fine particles 3b serve as a spacer in the die attach layer 3, and the die attach layer 3 at the time of joining the LED chip 2 and the bonding wire 7 using ultrasonic vibration or the like. It is possible to prevent the LED chip 2 from sinking into the LED and to strengthen the bonding between the LED chip 2 and the bonding wire 7.

  Furthermore, since the polyorganosiloxane 3a composition and the spherical silicone fine particles 3b constituting the die attach layer 3 are both excellent in heat resistance and UV resistance, the emission brightness is not lowered due to deterioration of the die attach material, and the long period of time can be maintained. Stable use is possible. Moreover, it can be expected that light incident on the die attach layer 3 is scattered by the spherical silicone fine particles 3b dispersed in the die attach layer 3 and contributes to the light emission luminance of the entire LED lamp.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples.

(Preparation examples, comparative preparation examples)
Each composition component shown in Table 1 was uniformly mixed in the amount (parts by weight) shown in Table 1 to prepare polyorganosiloxane (silicone) compositions containing spherical silicone fine particles (Preparation Examples 1 and 2). For comparison, a conventional polyorganosiloxane (silicone) composition (Comparative Preparation Examples 1 and 2) having a composition containing no spherical silicone fine particles in Preparation Examples 1 and 2 was prepared.

In Table 1, the abbreviations of various components are as follows.
Component (a) (alkenyl group-containing polyorganosiloxane)
M ^Vi D ₈₀ D ₁₀ ^Vi M ^Vi
In the formula, M ^Vi represents a monofunctional siloxy unit represented by (CH ₃ ) ₂ ViSiO _0.5 . Vi is a vinyl group (—CH═CH ₂ ).
D _{80 is (CH 3)} represents the 80 units of the bifunctional siloxy unit represented by 2 _{SiO, D} ^{10 Vi} _represents (CH 3) 10 units of bifunctional siloxy unit represented by ViSiO.
In addition, the position in the molecular chain of 10 units of the bifunctional siloxy unit represented by (CH ₃ ) ViSiO in D ₈₀ D ₁₀ ^Vi is arbitrary.
Further, this component has a silicon atom-bonded vinyl group content of 0.65 mmol / g and a viscosity at 23 ° C. of 200 mPa · s.

M ^Vi Q ₈ M ₅ Resin In the formula, M ^Vi is the same as in the case of M ^Vi D ₈₀ D ₁₀ ^Vi M ^Vi above,
Q is a tetrafunctional siloxy unit represented by SiO ₂ ,
M represents a monofunctional siloxy unit represented by (CH ₃ ) ₃ SiO _0.5 , respectively.
This component has a silicon atom-bonded vinyl group content of 1.0 mmol / g.

Component (b) (polyorganohydrogensiloxane)
MD _'20 D ₂₀ M
In the formula, M represents a monofunctional siloxy unit represented by (CH ₃ ) ₃ SiO _0.5 .
D ₂₀ represents 20 units of a bifunctional siloxy unit represented by (CH ₃ ) ₂ SiO, and D ′ ₂₀ represents 20 units of a bifunctional siloxy unit represented by (CH ₃ ) HSiO.
In addition, the position in the molecular chain of 20 units of the bifunctional siloxy unit represented by (CH ₃ ) HSiO in D ′ ₂₀ D ₂₀ is arbitrary.
Further, this component has a silicon atom-bonded hydrogen atom content of 8.7 mmol / g and a viscosity at 23 ° C. of 30 mPa · s.

(C) Component (platinum catalyst)
Platinum catalyst: platinum-vinylsiloxane complex (platinum atom content: 1700 ppm)
(Spherical silicone fine particles)
Spherical silicone fine particles (Tospearl 120): “Tospearl 120” is our product name, polyorganosilsesquioxane fine particles, average particle size 2 μm

<Evaluation of composition>
(1) Viscosity (JIS K-6249)
The viscosity of the polyorganosiloxane (silicone) composition containing spherical silicone fine particles of each of the preparation examples obtained above was measured according to JIS K-6249. Similarly, the viscosity of a polyorganosiloxane (silicone) composition containing no spherical silicone fine particles (comparative preparation example) was measured. The results are shown in the composition property column of Table 1.

(2) Hardness (JIS K-6253: Type D)
The silicone compositions of each of the preparation examples and comparative preparation examples obtained above were potted at a thickness of 6 mm in a Teflon (registered trademark) -coated mold, defoamed, and then heated in a hot air circulation heating furnace at 150 ° C. Cured by heating for hours. The obtained cured product was taken out from the mold, and the hardness was measured by JIS K-6253, Type D. The results are shown in the composition property column of Table 1.

(3) Light transmittance In the same manner as in (2) above, 2 mm-thick silicone resin test plates were prepared from the silicone compositions of Preparation Examples 1 and 2 and Comparative Preparation Examples 1 and 2, and the test plate was 300 nm thick. The light transmittance at a wavelength of ˜800 nm was measured using an ultraviolet-visible near-infrared spectrophotometer: UV-3600 (manufactured by Shimadzu Corporation). The results are shown in FIG.
Here, with respect to the light transmittance, if the composition other than that is the same, the composition containing the spherical silicone fine particles is slightly more transparent than the composition containing no spherical silicone fine particles, and when used as a die attach layer of a light emitting device. It has been found that it is possible to provide a slightly higher luminance than conventional products.

(Example)
Using the spherical silicone fine particle-containing polyorganosiloxane (silicone) composition obtained in Preparation Example 1, an LED lamp was produced by the following method.
As a support substrate, a concave PPA support substrate in which a lead electrode having electrode terminals on the inner bottom surface of a recess (cup) was mounted was prepared. After a certain amount of the silicone composition obtained in Preparation Example 1 was potted at a predetermined position on the bottom surface of the concave portion of the support substrate and defoamed, an LED chip was placed thereon, and a hot air circulation heating furnace at 150 ° C. The LED chip was adhered and fixed on the substrate by curing the silicone composition by heating for 1 hour. Subsequently, the LED chip electrode terminal bonded and fixed by the die attach layer (10 μm thickness) made of silicone resin in this way and the electrode terminal of the lead electrode were connected by a bonding wire (Au wire). The bonding of the LED chip electrode terminal, the lead electrode electrode terminal and the Au wire was performed by processing at 60,000 Hz for 0.5 seconds using a wire bonder device.

  An addition reaction curable polyorganosiloxane (silicone) composition prepared for forming a sealing layer: IVS4632 (trade name, manufactured by our company) is placed in a support substrate recess (cup) to which an LED chip and a bonding wire are fixed. After filling by potting to form a light emitting surface raised in a dome shape, the silicone composition was cured by heating for 1 hour in a 100 ° C. hot-air circulating heating furnace to obtain an LED lamp.

(Comparative example)
Comparative Example LED Lamp Except that the polyorganosiloxane (silicone) composition obtained in Comparative Preparation Example 2 was used instead of the silicone composition obtained in Preparation Example 1, the LED lamp of Comparative Example was exactly the same as in the above Example. Was made.
<Evaluation>

(1) Wire bonding property In the step of manufacturing the LED lamps of the above examples and comparative examples, the state immediately before forming the sealing layer is prepared as a test sample, and the bonding wire bonding property is obtained by the following method. evaluated.
The test was performed by the method based on the Wire Bond Shear Test Method of EIA / JESD22-B116.
Specifically, a pull test and a ball share test were performed on the test samples using a bonding tester / joint strength tester: PTR-1100 type (manufactured by Reska Co., Ltd.).
The pull test is performed by pulling the bonding wire and measuring the bonding point between the LED chip electrode terminal and the bonding wire, the bonding point between the lead electrode electrode terminal and the bonding wire, and the load when the bonding wire is broken, thereby performing wire bonding. The joint strength is evaluated as the loop strength. In the ball shear test, a load is applied from the side to the joint between the LED chip electrode terminal and the bonding wire, and the load when the joint breaks is measured to evaluate the wire bonding joint strength.
When the result of the pull test is 8 gf / wire or more and the result of the ball share test is 30 gf / wire or more, it is determined that the wire bonding strength is sufficient. The results are shown in Table 2 as “◯” when the strength is sufficient by the standard and “X” when the strength is insufficient.

(2) Luminance (initial, after heating test)
The LED lamps obtained in the above Examples and Comparative Examples were operated under the same conditions, and the luminance was measured with an illuminance meter. The LED lamp was subjected to a heating test in which the LED lamp was allowed to stand for 500 hours at a temperature of 150 ° C., and the emission luminance was measured in the same manner. The results are shown in Table 2 as a percentage when the initial light emission luminance of the LED lamp of the comparative example is 100%.

From these results, it is understood that when the die attach layer made of the polyorganosiloxane (silicone) composition containing spherical silicone fine particles according to the present invention is used in the light emitting device, the light emitting element and the bonding wire can be firmly bonded. In addition, the light emitting device of the present invention is excellent in thermal stability of light emission luminance, which can be said to be more than when a conventional silicone composition is used.
Regarding the initial light emission luminance, the LED lamp of the example is better than the comparative example, as shown in the result of the light transmittance, the difference in composition other than the spherical silicone fine particles of the composition of the adjustment example 1 and the composition of the comparative adjustment example 2 However, it should be considered that the spherical silicone fine particles have an effect of scattering light incident on the die attach layer and contribute to the improvement of the light emission luminance of the light emitting device as a whole.

  The light emitting device of the present invention can be firmly bonded between the light emitting element and the bonding wire by the structure of the die attach layer, and the die attach material itself is excellent in heat resistance and UV resistance. Is possible. Furthermore, the effect which scatters the light which injects into a die attach layer is acquired, and it can be anticipated that it contributes to the improvement of the light emission luminance as the whole light-emitting device. Therefore, it can be used in various applications such as portable terminals, liquid crystal panel backlights, and automobile applications, particularly in applications and fields that require long-term stable use.

It is sectional drawing which shows the structure of the LED lamp which is one Embodiment of this invention. It is sectional drawing which shows the structure of the LED lamp which is another one Embodiment of this invention. It is a graph which shows the light transmittance of the silicone resin for die attach layers used for this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Support substrate, 2 ... LED chip, 3 ... Die attach layer, 3a ... Polyorganosiloxane, 3b ... Spherical silicone fine particle, 5 ... Sealing layer, 6 ... Electrode terminal, 7 ... Bonding wire, 10, 20 ... LED lamp .

Claims (7)

A support substrate, an electrode terminal, a light emitting chip, a die attach layer for adhering and fixing the light emitting chip on the support substrate, a bonding wire connecting the electrode terminal and the light emitting chip, and the light emitting chip are sealed. A light-emitting device including a sealing layer formed as described above,
The light emitting device, wherein the die attach layer is mainly composed of polyorganosiloxane, and spherical silicone fine particles are contained and dispersed in the polyorganosiloxane.   2. The light emitting device according to claim 1, wherein the spherical silicone fine particles are fine particles made of polyorganosilsesquioxane.   The light emitting device according to claim 1 or 2, wherein the spherical silicone fine particles have an average particle size of 0.1 to 100 µm.   4. The light emitting device according to claim 1, wherein a content ratio of the spherical silicone fine particles is 0.1 to 50 wt% with respect to the polyorganosiloxane.   2. The light emitting device according to claim 1, wherein the polyorganosiloxane is a cured product of an addition reaction curable polyorganosiloxane composition. The addition reaction curable polyorganosiloxane composition is:
(A) a polyorganosiloxane having an alkenyl group bonded to an average of 0.5 or more silicon atoms in one molecule, and (b) a polyorganosiloxane having an average of two or more silicon atoms bonded to a silicon atom in one molecule. Organohydrogensiloxane in an amount such that the silicon-bonded hydrogen atoms in this component are 0.1 to 5.0 moles per mole of silicon-bonded alkenyl groups in component (a), and (c) catalyst. The light-emitting device according to claim 5, wherein each of the platinum-based catalysts is contained.   The light-emitting device according to claim 1, wherein the polyorganosiloxane further contains fine-particle silica.

Images