JP2018041858A - Cover sheet, sheet covering element, and optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cover sheet, excellent in heat resistance, maintaining light extraction efficiency high, and capable of covering an optical semiconductor element, a sheet covering element excellent in heat resistance, and an optical semiconductor device.SOLUTION: A cover sheet 1 includes: a phosphor layer 2 for covering an optical semiconductor element; and a low refractive index layer 3 disposed on a side of the phosphor layer 2 opposite to the optical semiconductor element and having a lower refractive index than the refractive index of the phosphor layer 2, in a thickness direction in order. The phosphor layer 2 contains a phenyl-based silicone resin. The low refractive index layer 3 has a thickness T exceeding 10 μm and contains a methyl-based silicone resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a covering sheet, a sheet covering element, and an optical semiconductor device, and more particularly to a covering sheet, a sheet covering element including an optical semiconductor element coated thereon, and an optical semiconductor device including the same.

  Conventionally, in an optical semiconductor device, in order to improve the extraction efficiency of light emitted from the optical semiconductor element, light in which the refractive index of the resin layer covering the optical semiconductor element is sequentially decreased from the optical semiconductor element side toward the outermost layer. Semiconductor devices are known.

  For example, a sheet for sealing an optical semiconductor element, in which a resin layer (B layer) having a refractive index lower than the refractive index of the A layer is laminated on the outermost resin layer (A layer) on the side in contact with the optical semiconductor element Has been proposed (see, for example, Patent Document 1).

  In the optical semiconductor element sealing sheet of Patent Document 1, the A layer is made of polycarbodiimide, and the B layer is made of an epoxy resin.

JP 2005-294733 A

  However, the optical semiconductor element sealing sheet described in Patent Document 1 has a problem that the reliability of the optical semiconductor device is lowered because the outermost resin layer (A layer) is deteriorated by heat.

  An object of the present invention is to provide a covering sheet that is excellent in heat resistance and capable of covering an optical semiconductor element while maintaining high light extraction efficiency, a sheet covering element that is excellent in heat resistance, and an optical semiconductor device.

  The present invention (1) includes a coating layer for coating an optical semiconductor element, and a low refractive index disposed on the opposite side of the optical semiconductor element with respect to the coating layer and having a refractive index lower than the refractive index of the coating layer A covering sheet containing a phenyl silicone resin, the low refractive index layer having a thickness exceeding 10 μm, and containing a methyl silicone resin. Including.

  According to this coating sheet, the refractive index of the coating layer and the low refractive index layer decreases in this order. Therefore, if the optical semiconductor element is coated with the coating layer, the light extraction efficiency can be improved. . Therefore, it is possible to obtain a sheet covering element and an optical semiconductor device that are provided with a covering sheet that covers the optical semiconductor element and are excellent in luminous efficiency.

  Further, since the low refractive index layer has a thickness exceeding 10 μm, the light extraction efficiency can be further improved.

  Furthermore, according to this covering sheet, since the covering layer contains the phenyl silicone resin, it is excellent in heat resistance. Furthermore, the coating layer containing the phenyl silicone resin and the low refractive index layer containing the methyl silicone resin have high affinity because both the phenyl silicone resin and the methyl silicone resin are the same silicone resin. Therefore, a sheet covering element and an optical semiconductor device having excellent reliability can be obtained.

  The present invention (2) includes the covering sheet according to (1), wherein the low refractive index layer has a thickness of 100 μm or less.

  In this covering sheet, since the low refractive index layer has a thickness of 100 μm or less, the covering sheet can be thinned. Therefore, a sheet covering element and an optical semiconductor device that can be thinned can be obtained.

  This invention (3) contains the coating sheet as described in (1) or (2) whose said methyl-type silicone resin is a C stage.

  In this covering sheet, since the methyl silicone resin is the C stage, the low refractive index layer can reliably support the covering layer.

  Further, even if the methyl silicone resin of the low refractive index layer is C-stage, both the methyl silicone resin contained in the low refractive index layer and the phenyl silicone resin contained in the coating layer are the same silicone resin. Therefore, the coating layer and the low refractive index layer are excellent in adhesion. Therefore, reliable covering of the optical semiconductor element by the covering layer can be ensured.

  This invention (4) contains the coating sheet as described in any one of (1)-(3) in which at least one surface in the thickness direction of the said low-refractive-index layer has uneven | corrugated shape.

  In this covering sheet, since at least one surface in the thickness direction of the low refractive index layer has an uneven shape, the light extraction efficiency can be further improved.

  This invention (5) contains the covering sheet as described in any one of (1)-(4) whose said phenyl-type silicone resin is a B stage.

  In this covering sheet, since the phenyl-based silicone resin is a B stage, the optical semiconductor element can be more reliably covered by the covering layer.

  The present invention (6) is a curve showing the relationship between the storage shear modulus G ′ and the temperature T obtained by dynamic viscoelasticity measurement of the coating layer under the conditions of a frequency of 1 Hz and a heating rate of 20 ° C./min. Has a minimum value, the temperature T at the minimum value is in the range of 40 ° C. or more and 200 ° C. or less, and the storage shear modulus G ′ at the minimum value is 1,000 Pa or more and 90,000 Pa or less. The covering sheet according to (5) is included.

  In this covering sheet, the covering layer can be pressure-sensitively bonded to the optical semiconductor element.

  This invention (7) contains the sheet | seat covering element which has a covering sheet as described in any one of (1)-(4), and the optical semiconductor element coat | covered with the said coating layer of the said covering sheet.

  Since this sheet covering element includes the optical semiconductor element coated on the covering sheet described above, the sheet covering element can be reduced in thickness while being excellent in heat resistance, light emission efficiency and reliability.

  This invention (8) contains the sheet | seat covering element as described in (7) further provided with the light reflection layer arrange | positioned at the side of the said optical semiconductor element when it sees from the thickness direction.

  In this sheet covering element, the light extraction efficiency can be improved by the light reflecting layer.

  The present invention (9) includes an optical semiconductor device comprising the sheet covering element according to (7) or (8) and a substrate on which the optical semiconductor element of the sheet covering element is mounted.

  Since this optical semiconductor device includes the above-described sheet covering element, it can be thinned while being excellent in heat resistance, light emission efficiency, and reliability.

  According to the covering sheet of the present invention, a sheet covering element and an optical semiconductor device excellent in heat resistance and light emission efficiency can be obtained. Moreover, this covering sheet can improve the heat-resistant reliability of the optical semiconductor element. Furthermore, the cover sheet can be thinned.

  According to the sheet covering element of the present invention, it is possible to reduce the thickness while being excellent in heat resistance, light emission efficiency and reliability.

  According to the optical semiconductor device of the present invention, it is possible to reduce the thickness while being excellent in heat resistance, light emission efficiency, and reliability.

FIG. 1 shows a cross-sectional view of the covering sheet of the first embodiment of the present invention. FIG. 2 shows a production process diagram of the covering sheet shown in FIG. FIG. 3 shows a cross-sectional view of a sheet-covered element including the cover sheet shown in FIG. 4A to 4C are manufacturing process diagrams of the sheet covering element shown in FIG. 3, where FIG. 4A is a first step of cutting the covering sheet, and FIG. 4B is arranging a plurality of covering sheets on the third release sheet. The second step, FIG. 4C, shows a third step of fixing the optical semiconductor element to the other surface in the thickness direction of the phosphor layer. 5D to 5F are a manufacturing process diagram of the sheet covering element shown in FIG. 3 and a manufacturing process diagram of the optical semiconductor device shown in FIG. 3 following FIG. 4C, and FIG. 5D shows a plurality of optical semiconductor elements by the light reflective layer. And the 4th process of sealing a plurality of covering sheets, Drawing 5E shows the 5th process which cuts an element aggregate, and Drawing 5F shows the process of mounting a sheet covering element on a substrate. FIG. 6 shows a cross-sectional view of a sheet-coated element according to the second embodiment of the present invention. 7A to 7D are a manufacturing process diagram of the sheet covering element shown in FIG. 6 and a manufacturing process diagram of the optical semiconductor device, in which FIG. 7A is a step of pressure-sensitively bonding the plurality of optical semiconductor elements to the phosphor layer. 7B shows a step of disposing the light reflective layer, FIG. 7C shows a step of removing the upper portion of the light reflective layer, and FIG. 7D shows a step of mounting the sheet covering element on the substrate. FIG. 8 shows a cross-sectional view of the sheet-coated element of the third embodiment of the present invention. 9A to 9F are manufacturing process diagrams of the sheet covering element shown in FIG. 8 and manufacturing process diagrams of the optical semiconductor device. FIG. 9A is a process of peeling the first release sheet, and FIG. 9B is an optical semiconductor. 9C is a step of pressure sensitively bonding the element to the phosphor layer, FIG. 9C is a step of placing the low refractive index layer on the fifth release sheet, FIG. 9D is a step of disposing a light reflective layer, and FIG. FIG. 9F shows a step of mounting the sheet covering element on the substrate. FIG. 10 shows a cross-sectional view of a sheet-covered element according to the fourth embodiment of the present invention. 11A to 11D are a manufacturing process diagram of the sheet covering element shown in FIG. 10 and a manufacturing process diagram of the optical semiconductor device. FIG. 11A is a process of arranging a plurality of optical semiconductor elements and a covering sheet to face each other. 11B shows a step of sealing a plurality of optical semiconductor elements with a phosphor layer, FIG. 11C shows a step of cutting the covering sheet, and FIG. 11D shows a step of mounting the sheet covering element on the substrate. FIG. 12 shows a cross-sectional view of the sheet-coated element of the fifth embodiment of the present invention. 13A to 13D are a manufacturing process diagram of the sheet covering element shown in FIG. 12 and a manufacturing process diagram of the optical semiconductor device. FIG. 13A is a process of arranging a plurality of optical semiconductor elements and a covering sheet to face each other. 13B shows a step of sealing a plurality of optical semiconductor elements with a phosphor layer, FIG. 13C shows a step of cutting the covering sheet, and FIG. 13D shows a step of mounting the sheet covering element on the substrate. 14A to 14B are manufacturing process diagrams of the optical semiconductor device according to the sixth embodiment of the present invention, in which FIG. 14A is a process of preparing a chip size package, and FIG. 14B is a cover sheet with respect to the chip size package. The process of hot pressing is shown. FIG. 15 shows the relationship between the storage shear modulus G ′ and the temperature T of the phosphor layers in Examples 1 and 8.

<First Embodiment>
A first embodiment of a covering sheet, a sheet covering element, and an optical semiconductor device of the present invention will be described.

1. Covering Sheet As shown in FIG. 1, the covering sheet 1 has a substantially plate (sheet) shape extending in a surface direction (a direction perpendicular to the thickness direction, including a left-right direction and a front-rear direction). The covering sheet 1 includes a phosphor layer 2 as an example of a covering layer and a low refractive index layer 3 in order toward one side in the thickness direction. The covering sheet 1 is preferably composed of only the phosphor layer 2 and the low refractive index layer 3.

2. As shown in FIG. 1, the phosphor layer 2 forms the other layer in the thickness direction on the other side in the thickness direction in the covering sheet 1. The phosphor layer 2 has a substantially plate (sheet) shape extending in the surface direction. The phosphor layer 2 is a layer for covering the optical semiconductor element 5 (see FIG. 5F). The phosphor layer 2 is a wavelength conversion layer that converts the wavelength of light emitted from the optical semiconductor element 5 (see FIG. 5F).

  The phosphor layer 2 includes a phenyl silicone resin and a phosphor.

2-1. Phosphor resin composition The phosphor layer 2 is made of, for example, a phosphor resin composition having a phenyl silicone resin and a phosphor.

  Specifically, the phosphor layer 2 is made of, for example, a phosphor resin composition having a B-staged phenyl silicone resin and a phosphor. Alternatively, the phosphor layer 2 is made of a phosphor resin composition having a C-stage phenyl silicone resin (phenyl silicone resin cured product) and a phosphor.

  More preferably, the phosphor layer 2 is formed in the shape described above from a B-staged phenyl silicone resin and a phosphor.

2-2. Phenyl Silicone Resin Phenyl silicone resin is a matrix resin that constitutes a matrix in which phosphors can be dispersed. The phenyl silicone resin is also a high refractive index resin for relatively increasing the refractive index of the phosphor layer 2. In addition, the phenyl silicone resin has excellent heat resistance.

  As the phenyl-based silicone resin, for example, a one-stage reaction-curable silicone resin that has one reaction mechanism and can be changed from the A stage to the C stage (completely cured) in the first stage reaction, for example, It has two reaction mechanisms. In the first stage reaction, the A stage is changed to the B stage (semi-curing), and then in the second stage reaction, the B stage is changed to the C stage (complete curing). And a thermosetting silicone resin such as a two-stage reaction curable silicone resin. The first-stage reaction curable silicone resin can be changed from the A stage to the B stage in the middle of the first stage reaction, and the subsequent stage heating can cause the first stage reaction. It includes a thermosetting silicone resin that can be resumed to be C-staged (completely cured) from the B-stage. That is, such a one-step reaction-curable silicone resin includes a one-step reaction-curable silicone resin that can be a B-stage. The one-stage reaction curable silicone resin cannot be controlled to stop in the middle of the one-stage reaction, that is, cannot become the B stage, and is changed from the A stage to the C stage (completely cured) 1 Also included is a step reaction curable silicone resin. That is, such a thermosetting silicone resin can also include a one-step reaction curable resin that cannot be a B-stage.

  In addition, the phenyl silicone resin cured product (product) obtained by C-stage of the phenyl silicone resin has, for example, a methyl group and a phenyl group in the main skeleton which is a siloxane bond, or, for example, siloxane The main skeleton that is a bond has only a phenyl group. Preferably, the cured phenyl-based silicone resin has a methyl group and a phenyl group in the main skeleton that is a siloxane bond.

In the phenyl-based silicone resin cured product (product), the content ratio of the phenyl group in the hydrocarbon group directly bonded to the silicon atom is, for example, 30 mol% or more, preferably 35 mol% or more. It is 55 mol% or less, preferably 50 mol% or less. The phenyl group content is calculated by ²⁹ Si-NMR. Details of the method for calculating the phenyl group content are described in, for example, WO2011 / 125463.

  As the phenyl silicone resin, a thermosetting silicone resin that can be a B stage is preferable, and a one-stage reaction curable silicone resin that can be a B stage is more preferable.

  Specifically, the one-stage reaction-curable silicone resin that can be a B-stage is a thermoplastic that is once plasticized (or liquefied) by heating in the B-stage and then cured (C-stage) by further heating.・ It is a thermosetting silicone resin.

  B-staged phenyl silicone resins (especially those having a storage shear modulus G ′ of 1,000 Pa or more, which will be described later) soften (show a minimum point) in the above-described further heating, but are generally thermoplastic. -It is harder than a thermosetting silicone resin, and the phosphor layer 2 can be held in the above-described further heating.

  One-stage reaction-curable silicone resins that can be B-stages are described in, for example, JP-A-2006-037562 and JP-A-2006-119454.

  The refractive index of the phenyl silicone resin is, for example, 1.45 or more, preferably 1.50 or more, more preferably 1.53 or more, and still more preferably 1.55 or more. 75 or less, preferably 1.65 or less.

  The content ratio of the phenyl silicone resin is, for example, 10% by mass or more, preferably 20% by mass or more, for example, 95% by mass or less, preferably 90% by mass or less, with respect to the phosphor resin composition. is there.

2-3. Phosphor The phosphor is a particle (wavelength convertible particle) that can convert the wavelength of light emitted from the optical semiconductor element 5 (see FIG. 5F). Examples of the phosphor include a yellow phosphor that can convert blue light into yellow light, and a red phosphor that can convert blue light into red light.

Examples of the yellow phosphor include silicate phosphors such as (Ba, Sr, Ca) ₂ SiO ₄ ; Eu, (Sr, Ba) ₂ SiO ₄ : Eu (barium orthosilicate (BOS)), for example, Y ₃ Al Garnet-type phosphors having a garnet-type crystal structure such as ₅ O ₁₂ : Ce (YAG (yttrium, aluminum, garnet): Ce), Tb ₃ Al ₃ O ₁₂ : Ce (TAG (terbium, aluminum, garnet): Ce) Examples thereof include oxynitride phosphors such as Ca-α-SiAlON.

Examples of the red phosphor include nitride phosphors such as CaAlSiN ₃ : Eu and CaSiN ₂ : Eu.

  The phosphor is preferably a yellow phosphor, and more preferably a garnet phosphor.

  Examples of the shape of the phosphor include a spherical shape, a plate shape, and a needle shape.

  The phosphors can be used alone or in combination.

  The average particle size of the phosphor is, for example, 0.25 μm or more, preferably 1 μm or more, and for example, 200 μm or less, preferably 100 μm or less. If the average particle diameter of the phosphor is not less than the above lower limit, the wavelength of the light emitted from the optical semiconductor element 5 (see FIG. 5F) can be reliably converted. The average particle diameter is calculated as a D50 value, and specifically measured by a laser diffraction particle size distribution meter. The average particle diameter of the subsequent particles is also determined in the same manner as described above.

  The phosphors can be used alone or in combination.

  The proportion of the phosphor is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and for example, 1000 parts by mass or less, preferably 500 parts by mass or less with respect to 100 parts by mass of the phenyl-based silicone resin. It is. The content ratio of the phosphor is, for example, 5% by mass or more, preferably 10% by mass or more, for example, 90% by mass or less, preferably 80% by mass or less, with respect to the phosphor resin composition.

2-4. Particles other than phosphor The phosphor resin composition may further contain particles other than the phosphor.
Examples of such particles include fillers and thixotropic particles. These can be used alone or in combination.

(1) Filler The filler is optionally blended in the phosphor resin composition in order to strengthen the phosphor layer 2 and increase the amount of the phosphor resin composition.

  The filler is particles that have substantially the same refractive index as the phenyl silicone resin. The filler is allowed to have a refractive index that approximates that of phenyl silicone resin, for example. Specifically, the refractive index difference between the filler and the phenyl silicone resin is allowed to be a minute value of, for example, 0.05 or less, and further 0.04 or less.

  Such particles are selected from, for example, inorganic particles and organic particles.

Examples of the inorganic particles include silica (SiO ₂ ), talc (Mg ₃ (Si ₄ O ₁₀ ) (HO) ₂ ), alumina (Al ₂ O ₃ ), boron oxide (B ₂ O ₃ ), calcium oxide (CaO). ), Zinc oxide (ZnO), strontium oxide (SrO), magnesium oxide (MgO), zirconium oxide (ZrO ₂ ), barium oxide (BaO), antimony oxide (Sb ₂ O ₃ ), and other oxides such as aluminum nitride Examples thereof include inorganic particles (inorganic materials) such as nitrides such as (AlN) and silicon nitride (Si ₃ N ₄ ). Examples of the inorganic particles include composite inorganic particles prepared from the inorganic materials exemplified above, and specifically, composite inorganic oxide particles (specifically, glass particles) prepared from an oxide. Can be mentioned.

  Examples of the organic particles include acrylic resin particles, styrene resin particles, acrylic-styrene resin particles, silicone resin particles, polycarbonate resin particles, benzoguanamine resin particles, polyolefin resin particles, polyester resin particles, and polyamides. Resin particles, polyimide resin particles, and the like.

  The filler can be used alone or in combination.

  Preferably, inorganic oxide particles, more preferably glass particles are used.

  The shape of the filler is not particularly limited, and examples thereof include a spherical shape, a plate shape, and a needle shape.

  The average particle diameter of the filler is, for example, 0.25 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, further preferably 1 μm or more, and for example, 200 μm or less, preferably , 100 μm or less.

  The proportion of the filler is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, for example, 250 parts by mass or less, preferably 150 parts by mass or less, with respect to 100 parts by mass of the phenyl silicone resin. It is. The content of the filler in the phosphor resin composition is, for example, 5% by mass or more, preferably 10% by mass or more, and for example, 70% by mass or less, preferably 60% by mass or less.

(2) Thixotropic particle The thixotropic particle is a thixotropic agent that imparts or improves thixotropy to the phosphor resin composition. Thixotropy is a property in which the viscosity gradually decreases when subjected to shear stress, and the viscosity gradually increases when stationary. Examples of the thixotropic particles include nano silica such as fumed silica (fumed silica). The fumed silica may be, for example, either hydrophobic fumed silica whose surface has been hydrophobized by a surface treating agent such as dimethyldichlorosilane or silicone oil, or hydrophilic fumed silica that has not been surface-treated.

  The average particle size of the thixotropic particles is, for example, 200 nm or less, preferably 50 nm or less, and for example, 1 nm or more, preferably 5 nm or more.

  The thixotropic particles can be used alone or in combination.

  The ratio of the thixotropic particles is, for example, 0.1 parts by mass or more, preferably 0.2 parts by mass or more, and for example, 10 parts by mass or less, preferably 100 parts by mass of the phosphor resin composition. Is 5 parts by mass or less. The content ratio of the thixotropic particles in the phosphor resin composition is, for example, 0.1% by mass or more, preferably 0.2% by mass or more, and for example, 10% by mass or less, preferably 5% by mass. It is as follows.

2-5. Preparation of phosphor resin composition The phosphor resin composition is prepared by blending and mixing a phenyl silicone resin, a phosphor, and, if necessary, particles other than the phosphor.

2-6. Properties and Dimensions of Phosphor Layer 2 When the phenyl silicone resin is B-stage, that is, when phosphor layer 2 is B-stage, this phosphor layer 2 has a frequency of 1 Hz and a heating rate of 20 ° C. The curve showing the relationship between the storage shear modulus G ′ and the temperature T obtained by measuring the dynamic viscoelasticity under the conditions of / min has a minimum value as shown in FIG.

  And the temperature T in such a minimum value exists in the range of 40 degreeC or more and 200 degrees C or less, and the storage shear modulus G 'in the above-mentioned minimum value exists in the range of 5 Pa or more and 90,000 Pa or less, for example. .

  The storage shear modulus G ′ at the above-mentioned minimum value is preferably 10 Pa or more, more preferably 15 Pa or more, still more preferably 20 Pa or more, and preferably 1,000 Pa or less, preferably 750 Pa or less. More preferably, it is 250 Pa or less, more preferably 100 Pa or less, particularly preferably less than 50 Pa. If the storage shear modulus G ′ at the minimum value is equal to or less than the above-described upper limit, the sheet covering element 4 including the phosphor layer 2 having various shapes (FIGS. 3, 6, 8, 10, and 12 described later). Furthermore, the optical semiconductor device 8 (FIG. 14B described later) can be manufactured.

  Alternatively, the temperature T at the minimum value is in the range of 40 ° C. or more and 200 ° C. or less, and the storage shear modulus G ′ at the above minimum value is preferably 1,000 Pa or more, more preferably 10,000 Pa or more. More preferably, it is 20,000 Pa or more, more preferably 30,000 Pa or more, and preferably 70,000 Pa or less. If the storage shear modulus G ′ at the minimum value is equal to or greater than the lower limit described above, in the third step (described later) shown in FIG. 5D, wrinkles of the phosphor layer 2 are prevented and the thickness of the phosphor layer 2 becomes uniform. The obtained sheet covering element 4 and the optical semiconductor device 8 (see FIG. 5F) are excellent in color uniformity. If the storage shear modulus G ′ at the minimum value is not more than the above upper limit, the optical semiconductor element 5 can be reliably pressure-sensitively bonded to the phosphor layer 2 in the third step (described later) shown in FIG. 4C.

  The refractive index of the phosphor layer 2 is, for example, 1.45 or more, preferably 1.50 or more, more preferably 1.53 or more, and for example, 1.75 or less.

  The refractive index is obtained by measuring with an Abbe refractometer.

  In addition, each refractive index of the phenyl-type silicone resin of A stage, B stage, and C stage is substantially the same.

  The thickness of the fluorescent substance layer 2 is 30 micrometers or more, for example, Preferably, it is 50 micrometers or more, for example, is 1000 micrometers or less, Preferably, it is 500 micrometers or less.

3. Low Refractive Index Layer As shown in FIG. 1, the low refractive index layer 3 forms a thickness direction one side layer located on the thickness direction one side in the covering sheet 1. The low refractive index layer 3 has a substantially plate (sheet) shape extending in the surface direction. The low refractive index layer 3 is disposed on the one surface in the thickness direction of the low refractive index layer 3 so as to be in contact with the entire surface of the one surface in the thickness direction of the phosphor layer 2. The low refractive index layer 3 emits light emitted from an optical semiconductor element 5 (see FIG. 5F), which will be described later, and passes through the phosphor layer 2 and light wavelength-converted by the phosphor layer 2 (side outside). ) Is refracted (or diffused).

  The low refractive index layer 3 has a lower refractive index (described later) than the refractive index of the phosphor layer 2.

  The low refractive index layer 3 includes a flat first surface (the other surface in the thickness direction) 41 that is parallel to the surface direction, and a second surface (one surface in the thickness direction) 42 that is opposed to the first surface 41 and has an uneven shape. And have.

  The first surface 41 is a contact surface that contacts one surface in the thickness direction of the phosphor layer 2.

  The second surface 42 is an exposed surface that is exposed outward (one in the thickness direction). The concave-convex shape of the second surface 42 is a shape that exhibits a brightness enhancement effect in the low refractive index layer 3, and examples thereof include a hemispherical lens shape, a pyramid shape, a cone shape, and a bell shape. Details and dimensions of the uneven shape of the second surface 42 are described in, for example, Japanese Patent Application Laid-Open No. 2007-110053, Japanese Patent Application Laid-Open No. 2010-192586, and the like. The surface roughness of the second surface 42 (arithmetic mean roughness Ra defined by JIS B 0601: 2001) is, for example, 0.05 μm or more, preferably 0.1 μm or more, more preferably 0.2 μm. For example, it is 3 μm or less.

  The low refractive index layer 3 contains a methyl silicone resin.

  For example, the low refractive index layer 3 is formed in the above-described shape from a low refractive resin composition containing a methyl silicone resin. Preferably, the low refractive index layer 3 is made of a low refractive index resin composition containing a C-stage methyl silicone resin (methyl silicone resin cured product).

3-1. Methyl Silicone Resin Methyl silicone resin is a low refractive index resin blended in a low refractive resin composition in order to lower the refractive index of the low refractive index layer 3 relative to the refractive index of the phosphor layer 2. . The methyl silicone resin is also a matrix resin that constitutes a matrix that can disperse the filler and thixotropic particles when the filler and thixotropic particles described later are blended in the low refractive index resin composition.

  Examples of the methyl silicone resin include a C-stage thermosetting silicone resin (cured silicone resin) in which a one-stage reaction-curable silicone resin and a two-stage reaction-curable silicone resin are converted to a C-stage. The methyl silicone resin preferably includes a cured silicone resin in which a one-stage reaction-curable silicone resin that can be C-staged (completely cured) from the A-stage is C-staged.

  Note that the C-stage methyl silicone resin has substantially only a methyl group in the main skeleton which is a siloxane bond. Specifically, the content ratio of the methyl group in the hydrocarbon group directly bonded to the silicon atom is, for example, 90 mol% or more, preferably 95 mol% or more, more preferably 99 mol% or more, and further preferably Is 100 mol%.

  The refractive index of the methyl silicone resin is, for example, less than 1.50, preferably 1.45 or less, and for example, 1.3 or more, preferably 1.35 or more. Difference in refractive index between methyl silicone resin and phenyl silicone resin (the value obtained by subtracting the refractive index of methyl silicone resin from the refractive index of phenyl silicone resin is, for example, 0.05 or more, preferably 0.1 or more For example, the ratio of the refractive index of the phenyl silicone resin to the refractive index of the methyl silicone resin is, for example, 1.05 or more. , Preferably 1.07 or more, and for example 1.2 or less, preferably 1.15 or less.

  The content ratio of the methyl silicone resin is, for example, 50% by mass or more, preferably 80% by mass or more, for example, 100% by mass or less, preferably 90% by mass or less, with respect to the low flexural resin composition. It is.

3-2. Fillers, etc. The low refractive index resin composition can contain particles such as fillers and thixotropic particles, if necessary.

(1) Filler The filler is optionally blended in the low refractive index resin composition in order to reinforce the low refractive index layer 3 and increase the amount of the low refractive index resin composition.

  The filler is particles that have substantially the same refractive index as that of the methyl silicone resin. The filler is allowed to have a refractive index that approximates that of methyl silicone resin, for example. Specifically, the refractive index difference between the filler and the methyl silicone resin is allowed to be a minute value of, for example, 0.05 or less, and further 0.04 or less.

  Examples of the filler include those exemplified for the phosphor resin composition, preferably organic particles, more preferably silicone resin particles.

  The proportion of the filler is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and for example, 250 parts by mass or less, preferably 150 parts by mass or less with respect to 100 parts by mass of the methyl silicone resin. It is. The content of the filler in the phosphor resin composition is, for example, 5% by mass or more, preferably 10% by mass or more, and for example, 70% by mass or less, preferably 60% by mass or less.

(2) Thixodonating particles The thixotropic particles may be of the same type as the thixotropic particles exemplified in the phosphor resin composition, and their physical properties and blending ratio are the same as above.

3-3. Physical Properties and Dimensions of Low Refractive Index Layer The compression elastic modulus at 25 ° C. of the low refractive index layer 3 is, for example, more than 1.2 MPa, preferably more than 1.4 MPa, and for example, 15 MPa or less, preferably 10 MPa or less. The compression elastic modulus of the low refractive index layer 3 is obtained by the method described in “Plastics—Method for obtaining compression characteristics” of JIS K 7181: 2011. If the compression elastic modulus of the low refractive index layer 3 exceeds the lower limit described above, the low refractive index layer 3 reliably supports the phosphor layer 2 and ensures the reliable covering of the optical semiconductor element 5 by the phosphor layer 2. be able to.

  The thickness T of the low refractive index layer 3 exceeds 10 μm, preferably 15 μm or more, and more preferably 25 μm or more. If the thickness T of the low refractive index layer 3 is less than the lower limit, the light extraction efficiency cannot be improved. On the other hand, if the thickness T of the low refractive index layer 3 exceeds the lower limit described above, the light extraction efficiency can be improved.

  The thickness T of the low refractive index layer 3 is, for example, 500 μm or less, preferably 150 μm or less, more preferably 100 μm or less, and still more preferably 85 μm or less. If the thickness T of the low refractive index layer 3 is equal to or less than the above upper limit, the cover sheet 1 can be thinned.

  The refractive index of the low refractive index layer 3 is, for example, 1.30 or more, preferably 1.35 or more, and for example, 1.55 or less, preferably 1.50 or less. If the refractive index of the low refractive index layer 3 is not more than the above upper limit, the refractive index of the low refractive index layer 3 can be reliably set lower than the refractive index of the phosphor layer 2, and the light extraction efficiency by the cover sheet 1 can be increased. Can be improved.

  The refractive index difference between the low refractive index layer 3 and the phosphor layer 2 (a value obtained by subtracting the refractive index of the low refractive index layer 3 from the refractive index of the phosphor layer 2) is, for example, 0.5 or less, preferably 0. .3 or less, preferably 0.2 or less, and for example, 0.03 or more. The ratio of the refractive index of the phosphor layer 2 to the refractive index of the low refractive index layer 3 is, for example, 1.05 or more, preferably 1.07 or more, and for example, 1.25 or less, preferably Is 1.15 or less.

  The compression elastic modulus at 25 ° C. of the covering sheet 1 is not particularly limited, and is, for example, 150 MPa or less, preferably less than 80 MPa, more preferably 10 MPa or less, and 0.1 MPa or more. If the compressive elastic modulus is equal to or lower than the above upper limit, the covering sheet 1 is excellent in flexibility and moldability. Therefore, the sheet covering element 4 including the phosphor layer 2 having various shapes, and the optical semiconductor device 8 are manufactured. be able to.

  Specifically, when the compressive elastic modulus is 150 MPa or less, the sheet covering element 4 shown in FIGS. 3, 6, 8, and 10 can be manufactured. Furthermore, if the compression modulus is less than 80 MPa, the sheet covering element 4 shown in FIGS. 3, 6, 8, 10, and 12 can be manufactured. If the compression modulus is 10 MPa or less, the sheet covering element 4 shown in FIGS. 3, 6, 8, 10, and 12, and the optical semiconductor device 8 shown in FIG. 14B can be manufactured.

4). Manufacturing method of covering sheet In order to manufacture the covering sheet 1, for example, as shown in FIG. 2, first, the phosphor layer 2 is manufactured, and the low refractive index layer 3 is separately manufactured, and then the phosphor layer 2 is manufactured. And the low refractive index layer 3 is bonded together.

(1) Production of phosphor layer To produce the phosphor layer 2, first, the above-described components are blended and mixed to prepare a phosphor resin composition (varnish). Next, the phosphor resin composition is applied to the surface (one surface in the thickness direction) of the first release sheet 21.

  The 1st peeling sheet 21 consists of a flexible film extended in a surface direction, for example. Examples of the first release sheet 21 include polymer films such as a polyethylene film, a polyester film, and an epoxy resin, such as a ceramic sheet, such as a metal foil. Moreover, the sticking surface of the 1st peeling sheet 21, ie, the contact surface with respect to the fluorescent substance layer 2, is peeled off if necessary, such as a fluorine treatment. The thickness of the 1st peeling sheet 21 is 1 micrometer or more, for example, Preferably, it is 10 micrometers or more, for example, is 2,000 micrometers or less, Preferably, it is 1,000 micrometers or less.

  Next, when the phenyl silicone resin is a thermosetting silicone resin that can be a B-stage, the A-stage phenyl silicone resin is B-staged. Specifically, the A stage phosphor resin composition is heated (baked) to form a B stage.

  The heating (baking) condition is appropriately set so that the storage shear modulus G ′ in the dynamic viscoelasticity measurement in the phosphor layer 2 is in a desired range (described later).

  That is, the heating temperature is appropriately set depending on the composition of the phenyl silicone resin in the phosphor resin composition, and specifically, for example, 50 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. or higher. For example, it is 120 degrees C or less, Preferably, it is 100 degrees C or less. When the heating temperature is not less than the above lower limit and / or the heating temperature is not more than the above upper limit, the minimum value of the above-described storage shear modulus G ′ can be set in a desired range.

  The heating time is, for example, 2.5 minutes or more, preferably 5.5 minutes or more, and for example, 4 hours or less, preferably 1 hour or less, more preferably 30 minutes or less, still more preferably, 10 minutes or less. If the heating time is not less than the above lower limit and / or not more than the above upper limit, the minimum value of the above-described storage shear modulus G ′ can be set in a desired range.

  Thereby, the phosphor layer 2 is formed on the surface (one surface in the thickness direction) of the first release sheet 21.

  Preferably, the B-stage phosphor layer 2 is produced.

  Specifically, the phosphor layer 2 containing a B-stage phenyl-based silicone resin is produced. Such a phosphor layer 2 has a desired storage shear modulus G ′ in a dynamic viscoelasticity measurement (a storage shear modulus G ′ at a minimum value is in a range of 5 Pa or more and 90,000 Pa or less).

(2) Production of Low Refractive Index Layer To produce the low refractive index layer 3, for example, first, the above-described components are blended and mixed to prepare a low refractive index resin composition (varnish).

  Next, the low refractive index resin composition is applied to the surface (the other surface in the thickness direction) of the second release sheet 22.

  The 2nd peeling sheet 22 consists of a flexible film extended in a surface direction, for example. Examples of the material of the second release sheet 22 include the same material as that of the first release sheet 21.

  The surface (the other surface in the thickness direction) of the second release sheet 22 has an uneven shape corresponding to the uneven shape of the second surface 42.

  In addition, the preparation methods of the 2nd peeling sheet 22 are described in Unexamined-Japanese-Patent No. 2007-110053, Unexamined-Japanese-Patent No. 2010-192586, etc., for example.

  Next, when the methyl silicone resin is a thermosetting silicone resin, the methyl silicone resin is C-staged. Specifically, the A-stage low refractive index resin composition is heated to form a C-stage.

  The heating temperature is, for example, 100 ° C. or higher, preferably 120 ° C. or higher, and for example, 150 ° C. or lower. The heating time is, for example, 10 minutes or longer, preferably 30 minutes or longer, and for example, 180 minutes or shorter, preferably 120 minutes or shorter.

  Thereby, the low refractive index layer 3 is produced on the surface (the other surface in the thickness direction) of the second release sheet 22.

  A C-stage low refractive index layer 3 is produced. At the same time, the irregular shape on the surface of the second release sheet 22 is transferred to the second surface 42 of the low refractive index layer 3.

(3) Bonding of phosphor layer and low refractive index layer Thereafter, the phosphor layer 2 and the low refractive index layer 3 are bonded together.

  Specifically, the exposed surface of the phosphor layer 2 supported by the first release sheet 21 and the exposed surface of the low-refractive index layer 3 supported by the second release sheet 22 are mutually connected by, for example, a laminator or the like. to paste together.

  Thereby, the covering sheet 1 including the phosphor layer 2 and the low refractive index layer 3 is manufactured in a state of being sandwiched (supported) by the first release sheet 21 and the second release sheet 22.

5. Sheet Covering Element, Optical Semiconductor Device, and Manufacturing Method Thereof Next, the sheet covering element 4, the optical semiconductor device 8 manufactured using the covering sheet 1, and the manufacturing method thereof will be described.

5-1. Sheet Covering Element Sheet covering element 4 is an element in which optical semiconductor element 5 is covered with covering sheet 1 as shown in FIG. 3, and optical semiconductor element 5 is covered with covering sheet 1 as shown in FIG. After being coated, it is mounted on a substrate 9 (described later).

  The sheet covering element 4 is not the optical semiconductor device 8, that is, does not include the substrate 9 provided in the optical semiconductor device 8. Specifically, the sheet covering element 4 includes an optical semiconductor element 5, a covering sheet 1 (phosphor layer 2 and low refractive index layer 3), and a light reflective layer 7. The sheet covering element 4 is preferably composed of an optical semiconductor element 5, a covering sheet 1, and a light reflective layer 7. That is, the optical semiconductor element 5 is configured so as not to be electrically connected to the electrode provided on the substrate 9 of the optical semiconductor device 8. The sheet covering element 4 is a component for manufacturing the optical semiconductor device 8, that is, a component for manufacturing the optical semiconductor device 8.

  The optical semiconductor element 5 is, for example, an LED (light emitting diode element) or LD (semiconductor laser element) that converts electrical energy into optical energy. Preferably, the optical semiconductor element 5 is a blue LED that emits blue light. The optical semiconductor element 5 does not include a rectifier (semiconductor element) such as a transistor having a technical field different from that of the optical semiconductor element.

  The optical semiconductor element 5 has a substantially flat plate shape along the plane direction. The optical semiconductor element 5 has a substantially rectangular shape in plan view (preferably, a substantially square shape in plan view). The optical semiconductor element 5 includes an electrode surface 11 on which the electrode 10 is provided, a facing surface 12 that faces the electrode surface 11 in the thickness direction (vertical direction), and a side surface 13 that connects the electrode surface 11 and the peripheral edge of the facing surface 12. And integrally.

  The electrode surface 11 is an example of a lower surface of the optical semiconductor element 5. A plurality (two) of electrodes 10 are provided on the electrode surface 11. Each of the plurality of electrodes 10 has a shape that slightly protrudes downward from the electrode surface 11.

  The facing surface 12 is an example of an upper surface of the optical semiconductor element 5.

  The dimensions of the optical semiconductor element 5 are set as appropriate. Specifically, the thickness (length in the vertical direction) is, for example, 0.1 μm or more, preferably 1 μm or more, more preferably 10 μm or more, For example, it is 500 micrometers or less, Preferably, it is 200 micrometers or less. The length in the left-right direction and / or the front-rear direction of the optical semiconductor element 5 is, for example, 200 μm or more, preferably 500 μm or more, and for example, 3000 μm or less, preferably 2000 μm or less.

  The covering sheet 1 is a refraction-wavelength conversion sheet that converts the wavelength of the sheet covering element 4 while refracting the light emitted from the optical semiconductor element 5 in the plane direction (side, side outside). The covering sheet 1 has a substantially rectangular flat plate shape in plan view. The covering sheet 1 includes the optical semiconductor element 5 when projected in the thickness direction. In the cover sheet 1, the phosphor layer 2 and the low refractive index layer 3 are sequentially arranged from the facing surface 12 of the optical semiconductor element 5 upward (the other side in the thickness direction). The low refractive index layer 3 forms the central portion of the upper surface of the sheet covering element 4. The upper surface of the low refractive index layer 3 is flush with the upper surface of a light reflective layer 7 described later. The central portion of the phosphor layer 2 is in contact (adhesion) with the facing surface 12 of the optical semiconductor element 5. The peripheral edge of the covering sheet 1 is located outside the optical semiconductor element 5 and is in contact with the light reflective layer 7.

  The light reflective layer 7 is a white layer that is disposed on the side of the optical semiconductor element 5 and the covering sheet 1 and that can reflect light emitted from the optical semiconductor element 5 mainly to the side. The light reflective layer 7 has a substantially rectangular frame shape in plan view. The light reflective layer 7 is integrally provided with a lower part 14 and an upper part 15 provided on the upper side.

  The lower portion 14 is disposed on the side of the optical semiconductor element 5 (the periphery, that is, the outer side in the left-right direction and the outer side in the front-back direction). Specifically, the lower part 14 contacts and covers the side surface 13 of the optical semiconductor element. The inner part of the lower part 14 is in contact with the lower surface of the phosphor layer 2. The outer part of the lower part 14 is continuous with the upper part 15. The lower part 14 has a substantially frame shape in plan view. The lower portion 14 is formed so that its inner shape matches the optical semiconductor element 5 and its outer shape matches the outer shape of the upper portion 15 when projected in the thickness direction. The thickness of the lower part 14 is the same as the thickness of the optical semiconductor element 5.

  The upper part 15 is arrange | positioned at the side (around, ie, the left-right direction outer side and the front-back direction outer side) of the coating sheet 1. Specifically, the upper part 15 is in contact with the peripheral side surface of the covering sheet 1 and covers them. The upper part 15 has a substantially frame shape in plan view. The upper portion 15 is formed so that its inner shape matches that of the covering sheet 1 and its outer shape matches that of the lower portion 14 when projected in the thickness direction. The opening in the upper part 15 is larger than the opening in the lower part 14. The thickness of the upper portion 15 is the same as the sum of the thickness T of the low refractive index layer 3 and the thickness of the phosphor layer 2.

  The light reflective layer 7 has a light transmittance of 20% or less, preferably 10% or less, for example, 0% or more when irradiated with light having a wavelength of 450 nm with a thickness of 100 μm.

  The light reflective layer 7 is formed (prepared) from, for example, a light reflective resin composition containing a resin and light reflective particles.

  Examples of the resin include thermosetting resins such as silicone resins and epoxy resins, preferably thermosetting resins that can be B-stages, and more preferably B-stages. A thermosetting silicone resin is mentioned, More preferably, a phenyl-type silicone resin is mentioned.

  Examples of the light-reflective particles include oxides such as titanium oxide, zinc oxide, zirconium oxide, and aluminum oxide, such as lead white (basic lead carbonate), carbonates such as calcium carbonate, and clay minerals such as kaolin. And inorganic materials. Preferably, titanium oxide is used. The refractive index of the light-reflecting particles is, for example, 2.0 or more, preferably 2.5 or more, and for example, 5.0 or less. The average particle diameter of the light reflective particles is, for example, 0.25 μm or more, preferably 1 μm or more, and for example, 200 μm or less, preferably 100 μm or less.

  The content ratio of the resin and the light reflecting particles is appropriately set according to the use and purpose.

5-2. Manufacturing method of sheet covering element And this sheet covering element 4 is a first step of cutting the covering sheet 1 (see FIG. 4A), the low refractive index layer 3 in the plurality of covering sheets 1 on the surface of the third release sheet 23 A second step of placing (see FIG. 4B), a third step of fixing each of the plurality of optical semiconductor elements 5 to the other surface in the thickness direction of the plurality of phosphor layers 2 (see FIG. 4C), the light reflective layer 7 The fourth step (see FIG. 5D) for covering the plurality of optical semiconductor elements 5 and the plurality of covering sheets 1, and the fifth step for manufacturing the plurality of sheet covering elements 4 by cutting the element assembly 17 (FIG. 5E). Manufactured in accordance with a method for manufacturing the sheet-covering element 4.

(1) 1st process As shown with the thick dashed line of Drawing 4A, in the 1st process, one sheet of covering sheet 1 is cut into the size according to a use and the purpose, and a plurality of sheets of covering sheet 1 are produced. To do. In cutting the cover sheet 1, the first release sheet 21 and the second release sheet 22 are cut together with the phosphor layer 2 and the low refractive index layer 3.

(2) Second Step In the second step, first, the second release sheet 22 is peeled from the low refractive index layer 3, and then the low refractive index layer 3 is turned into the third release sheet 23 as shown in FIG. 4B. Deploy. Specifically, the one surface in the thickness direction of the low refractive index layer 3 is brought into contact with the other surface in the thickness direction of the third release sheet 23. In addition, a plurality of the covering sheets 1 are arranged at intervals in the surface direction.

  As the 3rd release sheet 23, the thing similar to the 1st release sheet 21 is mentioned.

(3) Third Step In the third step, the optical semiconductor element 5 is disposed on the other surface in the thickness direction of the phosphor layer 2 as shown in FIG. 4C. Specifically, first, as indicated by an arrow in FIG. 4B, the first release sheet 21 is peeled from the phosphor layer 2, and then the opposing surface 12 of the optical semiconductor element 5 is placed in the thickness direction of the phosphor layer 2, etc. Contact (cover) the surface. As a result, the optical semiconductor element 5 is temporarily fixed (adhered) to the phosphor layer 2 of the B stage. The low refractive index layer 3 is located on the opposite side of the optical semiconductor element 5 with respect to the phosphor layer 2.

  Thereafter, when the phosphor layer is B-stage, specifically, when the phenyl silicone resin contained in the phosphor layer 2 is B-stage, the phosphor layer 2 is made C-stage.

  Specifically, the B-stage phosphor layer 2 is heated. The heating temperature is, for example, 100 ° C. or higher, preferably 120 ° C. or higher, and for example, 150 ° C. or lower. The heating time is, for example, 10 minutes or longer, preferably 30 minutes or longer, and for example, 180 minutes or shorter, preferably 120 minutes or shorter.

  The phosphor layer 2 is bonded to the optical semiconductor element 5 by forming a C-stage of the phenyl-based silicone resin contained in the phosphor layer 2.

  By the third step, preferably, a plurality of covering sheets 1 including the C-stage low-refractive index layer 3 and the C-stage phosphor layer 2 are produced while being supported by the third release sheet 23.

(4) Fourth Step Preferably, a plurality of covering sheets 1 including the C-stage low refractive index layer 3 and the C-stage phosphor layer 2 are supported by the third release sheet 23 by the third step. Produced.

  As shown in FIG. 5D, in the fourth step, for example, first, the light reflecting sheet 16 (virtual line) is opposed to the plurality of optical semiconductor elements 5 and the plurality of covering sheets 1 with an interval in the vertical direction. Deploy.

  First, the light reflecting sheet 16 is made of a light reflecting resin composition constituting the light reflecting layer 7 (preferably a B-stage phenyl silicone resin and light reflecting particles (refractive index is, for example, 2.0 or more, preferably Is formed in a sheet shape along a surface direction (a direction perpendicular to the vertical direction) from a light reflecting resin composition containing 2.3 or more, for example, 5.0 or less).

  Next, the plurality of optical semiconductor elements 5, the plurality of covering sheets 1, the third release sheet 23, and the light reflecting sheet 16 are set in a hot press machine (not shown). Specifically, the plurality of optical semiconductor elements 5 and the light reflecting sheet 16 are arranged to face each other.

  Next, as shown by the arrows in FIG. 5D, the light reflecting sheet 16 is hot pressed against the plurality of optical semiconductor elements 5 and the plurality of covering sheets 1.

  The conditions for the hot press are set so that the light reflecting sheet 16 is deformed by embedding the plurality of optical semiconductor elements 5 and the plurality of covering sheets 1.

  By this hot pressing, the light reflecting sheet 16 is formed on the light reflecting layer 7 having the lower portion 14 and the upper portion 15.

  As a result, an element assembly 17 including a plurality of optical semiconductor elements 5, a plurality of covering sheets 1, and one light reflective layer 7 is obtained in a state where it is supported by the third release sheet 23.

  Next, the light reflective layer 7 in the element assembly 17 is heated to form a C stage. Specifically, the element assembly 17 is taken out from the press machine 30 and heated by an oven or the like.

  Thereafter, the upper portion of the light reflective layer 7 is removed by, for example, grinding, wiping with a solvent, or peeling with an adhesive sheet. Thereby, the electrode surface 11 of the optical semiconductor element 5 is exposed.

(5) Fifth Step In the fifth step, as shown in FIG. 5E, the light reflective layer 7 located between the optical semiconductor elements 5 adjacent in the plane direction and between the covering sheets 1 adjacent in the plane direction. Is cut by, for example, dicing. Thereby, the element assembly 17 is separated into pieces.

  Subsequently, as shown by the arrow in FIG. 5E, the sheet covering element 4 is peeled from the third release sheet 23.

  Thus, a sheet covering element 4 including one optical semiconductor element 5, one covering sheet 1, and one light reflective layer 7 is obtained.

7-3. Thereafter, as shown in FIG. 5F, the sheet covering element 4 is mounted on the substrate 9. Specifically, the optical semiconductor element 5 is flip-chip mounted on the substrate 9. More specifically, the electrode 10 of the optical semiconductor element 5 is electrically connected to a terminal (not shown) provided on the substrate 9.

  Thus, an optical semiconductor device 8 including the substrate 9, the sheet covering element 4, and the light reflective layer 7 is obtained.

  The optical semiconductor device 8 preferably includes a substrate 9, an optical semiconductor element 5, a cover sheet 1, and a light reflective layer 7.

8). Advantageous Effects of First Embodiment According to this covering sheet 1, the phosphor layer 2 and the low refractive index layer 3 have a lower refractive index in this order. If it coat | covers, the extraction efficiency of light can be improved. Therefore, the covering sheet 1 that covers the optical semiconductor element 5 is provided, and the sheet covering element 4 and the optical semiconductor device 8 that are excellent in luminous efficiency can be obtained.

  Further, since the low refractive index layer 3 has a thickness T exceeding 10 μm, the light extraction efficiency can be further improved.

  Furthermore, according to this covering sheet 1, since the phosphor layer 2 contains a phenyl silicone resin, it is excellent in heat resistance. Furthermore, the phosphor layer 2 containing a phenyl silicone resin and the low refractive index layer 3 containing a methyl silicone resin are compatible with each other because the phenyl silicone resin and the methyl silicone resin are the same silicone resin. Is expensive. Therefore, the sheet covering element 4 and the optical semiconductor device 8 having excellent reliability can be obtained.

  In this covering sheet 1, if the low refractive index layer 3 has a thickness T of 100 μm or less, the covering sheet 1 can be thinned. Therefore, the sheet covering element 4 and the optical semiconductor device 8 that can be thinned can be obtained.

  In this covering sheet 1, if the methyl silicone resin is the C stage, the low refractive index layer 3 can reliably support the phosphor layer 2.

  Further, even if the methyl silicone resin is C-stage, both the methyl silicone resin contained in the low refractive index layer 3 and the phenyl silicone resin contained in the phosphor layer 2 are the same silicone resin. Therefore, the phosphor layer 2 and the low refractive index layer 3 are excellent in adhesion. Therefore, reliable covering of the optical semiconductor element 5 with the phosphor layer 2 can be ensured.

  In this covering sheet 1, since the 2nd surface 42 of the low refractive index layer 3 has uneven | corrugated shape, the light extraction efficiency can be improved further.

  Moreover, in this covering sheet 1, if the phenyl-based silicone resin is a B stage, the optical semiconductor element 5 can be more reliably covered by the phosphor layer 2.

  Moreover, in this coating sheet 1, the relationship between the storage shear elastic modulus G ′ and the temperature T obtained by measuring the dynamic viscoelasticity of the phosphor layer 2 under the conditions of a frequency of 1 Hz and a temperature increase rate of 20 ° C./min is shown. The curve shown has a minimum value, the temperature T at the minimum value is in the range of 40 ° C. or more and 200 ° C. or less, and the storage shear modulus G ′ at the minimum value is 1,000 Pa or more and 90,000 Pa or less. If it is within the range, the phosphor layer 2 can be pressure-sensitively bonded to the optical semiconductor element 5.

  Since the sheet covering element 4 includes the optical semiconductor element 5 covered on the covering sheet 1, the sheet covering element 4 can be thinned while being excellent in heat resistance, light emission efficiency, and reliability.

  In addition, since the sheet covering element 4 further includes the light reflective layer 7 disposed on the side of the optical semiconductor element 5 when viewed from the thickness direction, the light reflection layer improves the light extraction efficiency. be able to.

  Since the optical semiconductor device 8 includes the sheet covering element 4 described above, the optical semiconductor device 8 can be thinned while being excellent in heat resistance, light emission efficiency, and reliability.

9. Modified Example In the modified example, the same members and steps as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In 1st Embodiment, although the fluorescent substance layer 2 was mentioned as an example of the coating layer of this invention, it is not limited to this, It can also be set as the coating layer which does not contain fluorescent substance.

  On the other hand, if the coating layer is the phosphor layer 2, the wavelength of light emitted from the optical semiconductor element 5 can be converted. Therefore, the sheet covering element 4 and the optical semiconductor device 8 can extract light with high whiteness.

  In the first embodiment, as shown in FIG. 1, only the second surface 42 of the low refractive index layer 3 has an uneven shape. However, it is not limited to this.

  Although not shown, in the low refractive index layer 3, only the first surface 41 can have an uneven shape instead of the second surface 42, or the first surface 41 has an uneven shape together with the second surface 42. You can also.

  When the first surface 41 of the low refractive index layer 3 has an uneven shape, the other surface in the thickness direction of the phosphor layer 2 also has an uneven shape following the first surface 41.

  Further, neither the first surface 41 nor the second surface 42 of the low refractive index layer 3 may have an uneven shape.

  Preferably, at least one of the first surface 41 and the second surface 42 of the low refractive index layer 3 has an uneven shape. Thereby, the light extraction efficiency can be further improved.

  In the first embodiment, in the manufacturing method of the covering sheet 1, as shown in FIG. 2, each of the phosphor layer 2 and the low refractive index layer 3 is prepared, and then the phosphor layer 2 and the low refractive index layer 3 are formed. They are pasted together.

  However, for example, although not shown, the low refractive index layer 3 and the phosphor layer 2 can be sequentially laminated on the other side in the thickness direction of the second release sheet 22. Specifically, first, the low refractive index layer 3 (preferably, the C-stage low refractive index layer 3) is disposed on the other surface in the thickness direction of the second release sheet 22, and then the A-stage phosphor resin composition. Is applied to the other surface in the thickness direction of the low refractive index layer 3 and then heated. Preferably, the phosphor layer 2 of the B stage is formed on the other surface in the thickness direction of the low refractive index layer 3 of the C stage.

  In the first embodiment, as illustrated in FIG. 5D, the light reflective layer 7 is manufactured using the light reflecting sheet 16 indicated by the phantom line. For example, although not illustrated, the light reflecting sheet 16 is not used. The light-reflecting resin composition is directly disposed on the plurality of optical semiconductor elements 5 and the plurality of covering sheets 1 by coating or the like, and then the light-reflecting resin composition is C-staged to form the light-reflecting layer 7. It can also be produced.

  Also according to each modification mentioned above, there can exist an effect similar to 1st Embodiment.

Second Embodiment
In the second embodiment, the same members and steps as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the first embodiment, as shown in FIG. 3, in the sheet covering element 4, the covering sheet 1 has a size smaller than the light reflective layer 7 and larger than the optical semiconductor element 5 in plan view. .

  On the other hand, in 2nd Embodiment, as shown in FIG. 6, in the sheet | seat coating | coated element 4, the coating sheet 1 has the external shape of the same size as the light reflective layer 7 in planar view.

  The side surface of the covering sheet 1 and the side surface of the light reflective layer 7 are continuous in the thickness direction. Specifically, the side surface of the covering sheet 1 and the side surface of the light reflective layer 7 are flush with each other.

  The light reflective layer 7 does not have the upper part 15 (refer FIG. 3) in 1st Embodiment.

  In order to manufacture this sheet covering element 4 using the covering sheet 1, as shown in FIG. 1, first, the first release sheet 21 is peeled from the phosphor layer 2.

  Next, as shown in FIG. 7A, a plurality of optical semiconductor elements 5 are aligned and spaced apart from each other in the plane direction on the other surface in the thickness direction of the phosphor layer 2. Specifically, the facing surface 12 of the optical semiconductor element 5 is adhered (pressure-sensitive adhesion) to the other surface in the thickness direction of the phosphor layer 2 of the B stage.

  Subsequently, if the phosphor layer 2 is a B stage, the B stage phosphor layer 2 is heated to a C stage.

  Next, as shown in FIG. 7B, the light reflective layer 7 is disposed on the other surface in the thickness direction of the phosphor layer 2 so as to cover the plurality of covering sheets 1 and the plurality of optical semiconductor elements 5. Specifically, the light reflective layer 7 is filled between the adjacent covering sheets 1 and between the adjacent optical semiconductor elements 5.

  Next, as shown in FIG. 7C, the upper portion of the light reflective layer 7 is removed to expose the electrode surfaces 11 of the plurality of optical semiconductor elements 5.

  Next, as shown by a thick dashed line in FIG. 7C, the light reflective layer 7 and the covering sheet 1 between the adjacent optical semiconductor elements 5 are cut.

  Thereby, a plurality of sheet covering elements 4 including the optical semiconductor element 5, the covering sheet 1, and the light reflective layer 7 are obtained in a state where they are supported by the second release sheet 22.

  Thereafter, the sheet covering element 4 is peeled from the second release sheet 22 as indicated by an arrow in FIG. 7C.

  Thereafter, as shown in FIG. 7D, the sheet covering element 4 is flip-chip mounted on the substrate 9.

  Thereby, the optical semiconductor device 8 including the substrate 9 and the sheet covering element 4 is obtained.

  Also according to the second embodiment, the same effects as those of the first embodiment can be achieved.

<Third Embodiment>
In the third embodiment, members and steps similar to those in the first embodiment and the second embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the second embodiment, as shown in FIG. 6, the side surface of the covering sheet 1 and the side surface of the light reflective layer 7 are flush with each other.

  On the other hand, in the third embodiment, as shown in FIG. 8, the side surface of the cover sheet 1 and the side surface 13 of the light reflective layer 7 are flush with each other.

  The covering sheet 1 has the same shape as the optical semiconductor element 5 when projected in the thickness direction.

  In the light reflective layer 7, the inner surfaces of the lower part 14 and the upper part 15 are flush with each other in the thickness direction.

  In order to manufacture this sheet | seat covering element 4, as shown by the phantom line of FIG.

  Next, as shown in FIG. 9B, the optical semiconductor element 5 is disposed on the other surface in the thickness direction of the phosphor layer 2. Specifically, the facing surface 12 of the optical semiconductor element 5 is adhered (pressure-sensitive adhesion) to the other surface in the thickness direction of the phosphor layer 2 of the B stage.

  Subsequently, if the phosphor layer 2 is a B stage, the B stage phosphor layer 2 is heated to a C stage.

  Next, as shown in FIG. 9C, the second release sheet 22 is peeled from the low refractive index layer 3, and the low refractive index layer 3 is placed on another fourth release sheet 24.

  Examples of the fourth release sheet 24 include the same as the second release sheet 22. The fourth release sheet 24 has a size larger than that of the cover sheet 1 and the optical semiconductor element 5 in plan view.

  Thereafter, as shown in FIG. 9D, the light reflective layer 7 is disposed on the other side in the thickness direction of the fourth release sheet 24 so that the cover sheet 1 and the optical semiconductor element 5 are embedded by the light reflective layer 7.

  Subsequently, as shown in FIG. 9E, the upper portion of the light reflective layer 7 is removed to expose the electrode surface 11 of the optical semiconductor element 5.

  As a result, the sheet covering element 4 including the optical semiconductor element 5, the covering sheet 1, and the light reflective layer 7 is obtained in a state of being supported by the fourth release sheet 24.

  Thereafter, as shown in FIG. 9F, the sheet covering element 4 is flip-chip mounted on the substrate 9.

  Thereby, the optical semiconductor device 8 including the substrate 9, the sheet covering element 4, and the light reflective layer 7 is obtained.

  Also according to the third embodiment, the same effects as those of the first embodiment and the second embodiment can be achieved.

<Fourth embodiment>
In the fourth embodiment, members and processes similar to those in the first to third embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 10, the sheet covering element 4 does not include the above-described light reflective layer 7 but includes the optical semiconductor element 5, the phosphor layer 2, and the low refractive index layer 3. Preferably, the sheet covering element 4 includes only the optical semiconductor element 5, the phosphor layer 2, and the low refractive index layer 3.

  The phosphor layer 2 is disposed on the upper side and the side of the optical semiconductor element 5 so as to cover the facing surface 12 and the side surface 13 of the optical semiconductor element 5. That is, the phosphor layer 2 is arranged on the upper side and the periphery of the optical semiconductor element 5 so as to completely cover five surfaces (one opposing surface 12 and four side surfaces 13) other than the electrode surface 11 of the optical semiconductor element 5. Has been. The phosphor layer 2 includes the optical semiconductor element 5 when projected in the vertical direction. The phosphor layer 2 has a substantially rectangular tube shape extending in the vertical direction and closed at the upper end. Specifically, the phosphor layer 2 integrally includes an upper portion 18 disposed on the upper side of the optical semiconductor element 5 and a side portion 19 disposed on the side of the optical semiconductor element 5.

  The upper portion 18 has a substantially flat plate shape along the surface direction, and forms the outer shape of the phosphor layer 2 when projected in the thickness direction. The central portion of the lower surface of the upper portion 18 is in contact with the entire surface of the facing surface 12 of the optical semiconductor element 5, and the peripheral end portion of the upper portion 18 is continuous with the upper end portion of the side portion 19.

  The side portion 19 has a substantially rectangular frame shape (substantially rectangular tube shape) in plan view extending in the vertical direction. The side portion 19 is disposed around the optical semiconductor element 5 so as to contact and cover the side surface 13 of the optical semiconductor element 5. That is, the inner peripheral surface of the side portion 19 is in contact with the entire side surface 13 of the optical semiconductor element 5.

  The low refractive index layer 3 is in contact with the entire upper surface (one surface in the thickness direction) of the upper portion 18 of the phosphor layer 2. The low refractive index layer 3 has a substantially flat plate shape extending in the surface direction in the sheet covering element 4. The side surface (side end surface, peripheral surface) of the low refractive index layer 3 is continuous with the outer surface of the side portion 19 of the phosphor layer 2. That is, the side surface of the low refractive index layer 3 is flush with the outer surface of the side portion 19 of the phosphor layer 2.

  In order to manufacture this sheet covering element 4, first, as shown in FIG. 11A, a plurality of optical semiconductor elements 5 are aligned and arranged at intervals in the surface direction.

  Specifically, the electrode surface 11 of the optical semiconductor element 5 is temporarily fixed (pressure-sensitive adhesion) to the temporary fixing sheet 26. The temporary fixing sheet 26 has a substantially plate shape extending in the surface direction, and includes a pressure-sensitive adhesive layer on one surface in the thickness direction.

  Next, the covering sheet 1 is disposed so as to face the plurality of optical semiconductor elements 5 and the temporary fixing sheet 26 with an interval in the vertical direction. Specifically, the phosphor layer 2 and the optical semiconductor element 5 are opposed to each other. Specifically, the other surface in the thickness direction of the phosphor layer 2 is opposed to the facing surface 12 of the optical semiconductor element 5 in the vertical direction.

  In the covering sheet 1, the phosphor layer 2 is formed from a phosphor resin composition containing, for example, a B-stage phenyl-based silicone resin. Preferably, a thermoplastic / thermosetting silicone resin that can be sufficiently softened and deformed by heating (a thermoplastic / thermosetting silicone that exhibits a softer thermal behavior than a thermoplastic / thermosetting silicone resin that can retain its shape by heating) Resin) containing the phosphor resin composition. Specifically, the storage shear modulus G ′ at the above-described minimum value is formed from a phosphor resin composition having a range of, for example, 5 Pa or more and 1,000 Pa or less.

  The phosphor layer 2 has a thickness that allows the optical semiconductor element 5 to be sufficiently embedded by the following hot pressing. Specifically, the phosphor layer 2 has a thickness of, for example, 100 μm or more, preferably 150 μm or more.

  Subsequently, as shown in FIG. 11B, the covering sheet 1 is hot-pressed against the plurality of optical semiconductor elements 5 and the temporary fixing sheet 26.

  Thereby, the phosphor layer 2 is filled between the adjacent optical semiconductor elements 5. The phosphor layer 2 is deformed, and the phosphor layer 2 covers the side surface 13 and the facing surface 12 of the optical semiconductor element 5. The phosphor layer 2 has the above-described upper portion 18 and side portions 19 corresponding to the plurality of optical semiconductor elements 5.

  Subsequently, when the phosphor layer 2 is in the B stage, the phosphor layer 2 is changed to the C stage by heating.

  Next, as shown by a thick dashed line in FIG. 11C, the phosphor layer 2 between the optical semiconductor elements 5 adjacent in the plane direction and the low refractive index layer 3 thereon are cut.

  As a result, the sheet covering element 4 including one optical semiconductor element 5, one phosphor layer 2, and one low refractive index layer 3 is obtained in a state of being supported by the temporarily fixed sheet 26.

  Thereafter, as shown by the phantom lines in FIG. 11C, the sheet covering element 4 is peeled from the temporarily fixed sheet 26.

  As a result, a sheet covering element 4 having one optical semiconductor element 5, one phosphor layer 2, and one low refractive index layer 3 is obtained.

  Thereafter, as shown in FIG. 11D, the sheet covering element 4 is flip-chip mounted on the substrate 9.

  Thereby, the optical semiconductor device 8 including the substrate 9 and the sheet covering element 4 is obtained.

  Also according to the fourth embodiment, the same operational effects as those of the first to third embodiments can be achieved.

<Fifth Embodiment>
In the fifth embodiment, members and steps similar to those in the first to fourth embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the fifth embodiment, as shown in FIG. 12, the phosphor layer 2 further has a flange 20.

  The flange portion 20 is an overhanging portion that protrudes outward in the surface direction from the lower end portion of the side portion 19. The collar portion 20 has a substantially rectangular frame shape in plan view.

  The low refractive index layer 3 has a shape that follows the upper portion 18, the side portion 19, and the flange portion 20 of the phosphor layer 2. That is, the low refractive index layer 3 has substantially the same shape as the phosphor layer 2. The peripheral end surface of the low refractive index layer 3 is flush with the peripheral end surface of the flange 20 of the phosphor layer 2.

  In order to manufacture this sheet covering element 4, as shown in FIG. 13A, first, a plurality of optical semiconductor elements 5 are arranged on the upper surface (one surface in the thickness direction) of the temporarily fixing sheet 26 with a space in the plane direction. Align and arrange.

  Next, the covering sheet 1 is disposed so as to face the plurality of optical semiconductor elements 5 and the temporary fixing sheet 26 with an interval in the vertical direction.

  Subsequently, as shown in FIG. 13B, the covering sheet 1 is hot-pressed against the plurality of optical semiconductor elements 5 and the temporary fixing sheet 26.

  In the hot press, a mold 28 having a plurality of convex portions 27 corresponding to the flange portion 20 is used. Specifically, the mold 28 is disposed above the covering sheet 1 and the mold 28 is moved downward.

  In the covering sheet 1 pressed on the convex portion 27, the collar portion 20 is formed in the phosphor layer 2 in contact with the upper surface of the temporarily fixing sheet 26, and the low refractive index layer 3 follows the collar portion 20. .

  Subsequently, when the phosphor layer 2 is in the B stage, the phosphor layer 2 is changed to the C stage by heating.

  Next, as shown by a thick one-dot chain line in FIG. 13C, the flange portion 20 of the phosphor layer 2 and the low refractive index layer 3 thereon are cut.

  As a result, the sheet covering element 4 including one optical semiconductor element 5, one phosphor layer 2, and one low refractive index layer 3 is obtained in a state of being supported by the temporarily fixed sheet 26.

  Thereafter, as shown by the phantom lines in FIG. 13C, the sheet covering element 4 is peeled from the temporarily fixed sheet 26.

  As a result, a sheet covering element 4 having one optical semiconductor element 5, one phosphor layer 2, and one low refractive index layer 3 is obtained.

  Thereafter, as shown in FIG. 13D, the sheet covering element 4 is flip-chip mounted on the substrate 9.

  Thereby, the optical semiconductor device 8 including the substrate 9 and the sheet covering element 4 is obtained.

  Also according to the fifth embodiment, the same operational effects as those of the first to fourth embodiments can be achieved.

<Modifications of Fourth and Fifth Embodiments>
In this modification, members and steps similar to those in the fourth and fifth embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  The sheet covering element 4 (fourth embodiment) shown in FIG. 10 includes a flange portion 20 of the phosphor layer 2 in the sheet covering element 4 (fifth embodiment) obtained by the manufacturing method of FIGS. 13A to 13D, and Correspondingly, the low refractive index layer 3 covering the side portion 19 can be removed by cutting.

<Sixth Embodiment>
In the optical semiconductor device 8 of the sixth embodiment, as shown in FIG. 14B, the optical semiconductor element 5 is wire-bonded to a terminal (not shown) of the substrate 9 via a wire 29.

1. Optical Semiconductor Device As shown in FIG. 14B, the optical semiconductor device 8 is provided on the upper surface of the substrate 9, located around the optical semiconductor element 5, the optical semiconductor element 5 bonded to the substrate 9, and the optical semiconductor element 5. A light-reflective layer 7, a phosphor layer 2 that fills the light-reflective layer 7 and seals the optical semiconductor element 15, and a low-refractive index layer 3 that is positioned on the upper surface of the phosphor layer 2. Preferably, the optical semiconductor device 8 includes only the substrate 9, the optical semiconductor element 5, the light reflective layer 7, the phosphor layer 2, and the low refractive index layer 3.

  The optical semiconductor element 5 is electrically connected to the substrate 9 through a wire 29. The wire 29 has a linear shape, one end of which is electrically connected to a terminal (not shown) located on the electrode surface 11 of the optical semiconductor element 5, and the other end is a terminal (see FIG. (Not shown). The opposing surface 12 of the optical semiconductor element 5 is in contact with the upper surface of the substrate 9, while the electrode surface 11 of the optical semiconductor element 5 faces upward.

  The light reflective layer 7 is a housing having a frame shape surrounding the optical semiconductor element 5 in plan view. Further, the light reflective layer 7 is formed in a tapered cross section in which the opening cross-sectional area increases from the bottom to the top. The light reflective layer 7 may be prepared from white ceramics.

  The phosphor layer 2 covers the facing surface 12 and the side surface 13 of the optical semiconductor element 5 and seals the optical semiconductor element 5. The phosphor layer 2 also seals the wire 29. The upper surface of the phosphor layer 2 is flush with the upper surface of the light reflective layer 7.

  The low refractive index layer 3 covers the entire upper surface of the phosphor layer 2 and the upper surface of the light reflective layer 7. The low refractive index layer 3 has a substantially plate shape extending in the surface direction in the optical semiconductor device 8.

2. Method for Manufacturing Optical Semiconductor Device To manufacture the optical semiconductor device 8, first, as shown in FIG. 14A, a chip size package 30 including a substrate 9, an optical semiconductor element 5, and a light reflective layer 7 is prepared. .

  Separately, the covering sheet 1 is prepared, and the covering sheet 1 and the chip size package 30 are arranged to face each other with an interval in the vertical direction. Specifically, the covering sheet 1 is arranged so that the phosphor layer 2 faces the optical semiconductor element 5.

  The storage shear modulus G ′ at the above-described minimum value of the phosphor layer 2 in the cover sheet 1 is formed from a phosphor resin composition in the range of, for example, 5 Pa or more and 1,000 Pa or less.

  Next, the covering sheet 1 is hot-pressed in the vertical direction.

  When the phosphor layer 2 is a B stage, the phosphor layer 2 flows and is filled in the light reflective layer 7 by hot pressing, and the optical semiconductor element 5 is sealed. Specifically, the peripheral end portion of the phosphor layer 2 is hot-pressed on the lower surface of the peripheral end portion of the low refractive index layer 3 and the upper surface of the light reflective layer 7 and flows into the light reflective layer 7. At the same time, the opposing surface 12 and the side surface 13 of the optical semiconductor element 5 are covered together with the central portion of the phosphor layer 2.

  Thereafter, when the phosphor layer 2 is in the B stage, it is changed to the C stage. Thereby, the phosphor layer 2 seals the optical semiconductor element 5 and the wire 29. A low refractive index layer 3 is adhered to the upper surface of the phosphor layer 2.

  Thereby, the optical semiconductor device 8 is obtained.

3. Effects of the Sixth Embodiment Also according to the sixth embodiment, the same functions and effects as those of the first to fifth embodiments can be achieved.

  Preparation Examples, Examples and Comparative Examples are shown below to further illustrate the present invention, but the present invention is not limited to the Preparation Examples, Examples and Comparative Examples. Specific numerical values such as blending ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned “Mode for Carrying Out the Invention”, and the corresponding blending ratio (content ratio) ), Physical property values, parameters, etc. may be replaced with the upper limit values (numerical values defined as “less than” or “less than”) or lower limit values (numbers defined as “greater than” or “exceeded”). it can.

Preparation Example 1
(Preparation of phenyl silicone resin)
In accordance with Preparation Example 1 described in Examples of JP-A-2006-037562, an A-stage phenyl-based silicone resin (a one-stage reactive curable resin that can be a B-stage) was prepared.

  Thereafter, the A-stage phenyl-based silicone resin was reacted (completely cured, C-staged) at 100 ° C. for 1 hour to obtain a product.

Subsequently, ²⁹ Si-NMR of the obtained product was measured, and the proportion (mol%) occupied by the phenyl group in the hydrocarbon group directly bonded to the silicon atom was calculated to be 48%.

  Further, the refractive index of the C-stage phenyl-based silicone resin was 1.56 when measured at 25 ° C. at a wavelength of 589 nm using a multi-wavelength Abbe refractometer (iDR-M4 manufactured by ATAGO). .

Example 1
(1) Preparation of phosphor layer Phosphor (trade name “Y468”, YAG: Ce, average particle diameter 17 μm, manufactured by Nemoto Lumi Materials) 60 on 100 parts by mass of the A-stage phenyl silicone resin of Preparation Example 1 Mass parts, glass particles as a filler (refractive index 1.55, average particle diameter 20 μm, composition and composition ratio (mass%): SiO ₂ / Al ₂ O ₃ / CaO / MgO = 60/20/15/5 By mixing and mixing 100 parts by mass of inorganic particles) and 2 parts by mass of fumed silica (refractive index 1.41, average particle diameter 20 nm, R976s (manufactured by Nippon Aerosil Co., Ltd.) as thixotropic particles, a phosphor A resin composition was prepared.

  Subsequently, as shown in FIG. 2, the phosphor resin composition is heated on the surface of the first release sheet 21 (PET film, product name “SE-1”, thickness 50 μm, manufactured by Fujiko Co., Ltd.) with a thickness of 75 μm. Then, it was coated with a comma coater so as to be, and subsequently heated (baked) at 80 ° C. for 11.5 minutes. Thereby, the phosphor layer 2 of the B stage was produced while being supported by the first release sheet 21.

(2) Production of low refractive index layer Methyl silicone resin (refractive index 1.41, KER2500, methyl group content in hydrocarbon group bonded directly to silicon atom in C stage 100 mol%, manufactured by Shin-Etsu Silicone) A low refractive index resin composition (varnish) was prepared.

  Subsequently, as shown in FIG. 2, the low refractive index resin composition is applied to the surface (flat surface) of the second release sheet 22 having a flat surface with a comma coater so that the thickness after heating becomes 20 μm. Subsequently, it was heated at 150 ° C. for 3 hours. Thereby, the low refractive index layer 3 of the C stage was produced while being supported by the second release sheet 22.

(3) Bonding of phosphor layer and low refractive index layer Next, the phosphor layer 2 and the low refractive index layer 3 were bonded together by a laminator.

  Thus, the covering sheet 1 including the phosphor layer 2 and the low refractive index layer 3 was manufactured in a state of being sandwiched between the first release sheet 21 and the second release sheet 22.

  Thereafter, the sheet covering element 4 shown in FIG. 3 was manufactured by the method described in the first embodiment, and subsequently, the optical semiconductor device 8 shown in FIG. 5F was manufactured.

Examples 2-8 and Comparative Examples 1-7
Except having changed into the prescription of Table 1-Table 2, it processed similarly to Example 1 and manufactured the covering sheet 1. FIG.

  In Example 3, as shown in the enlarged view of FIG. 1, the low refractive index layer was processed in the same manner as in Example 1 except that the second surface 42 of the low refractive index layer 3 was formed in an uneven shape. 3 was produced. In Example 4, a low refractive index layer 3 was produced in the same manner as in Example 1 except that a filler was further added to the low refractive index resin composition. In Example 5, a filler was further added to the low refractive index resin composition, and, as shown in the enlarged view of FIG. 1, the second surface 42 of the low refractive index layer 3 was formed in an uneven shape, The low refractive index layer 3 was produced in the same manner as in Example 1.

  Specifically, in Examples 4 and 5, in “(2) Production of Low Refractive Index Layer”, methyl silicone resin (refractive index 1.41, KER2500, hydrocarbon directly bonded to silicon atom in C stage) 100% by mass of methyl group in the group, 100 parts by mass of Shin-Etsu Silicone Co., Ltd., silicone resin particles (refractive index 1.42, average particle size 2.0 μm, Tospearl TS120, Toshiba Silicone Co., Ltd.) as filler ) A low refractive index resin composition (varnish) was prepared by blending and mixing 40 parts by mass.

  Moreover, in Example 3 and 5, the 2nd peeling sheet 22 which has an uneven | corrugated shape on the surface was produced based on description of Example 1 of Unexamined-Japanese-Patent No. 2007-110053. Subsequently, as shown in FIG. 2, the low refractive index resin composition was applied to the surface (uneven surface) of the second release sheet 22 with a comma coater so that the thickness after heating was 50 μm, Heated at 150 ° C. for 3 hours.

  In addition, the numerical value of Table 1-Table 2 and a mixing | blending prescription column shows a mass part number, unless a unit is mentioned especially.

  For Comparative Example 1, a phosphor layer 2 made of polycarbodiimide and a low-refractive index layer 3 made of epoxy resin were prepared in accordance with the description in Example 1 of JP-A-2005-294733.

  Moreover, about the comparative example 5, the low refractive index layer 3 was not provided but the coating sheet 1 which consists of 1 layer of the phosphor layer 2 was produced.

Evaluation 1. Dynamic viscoelasticity of phosphor layer (storage shear modulus G ′)
Each of the B-stage phosphor layers 2 obtained in Example 1 and Example 8 was subjected to dynamic viscoelasticity measurement under the following conditions.

[conditions]
Viscoelastic device: Rotary rheometer (C-VOR device, manufactured by Malvern)
Sample shape: Disc shape Sample size: Thickness 225 μm, Diameter 8 mm
Distortion amount: 10%
Frequency: 1Hz
Plate diameter: 8mm
Gap between plates: 200 μm
Temperature rising rate 20 ° C / min Temperature range: 20-200 ° C
A curve showing the relationship between the storage shear modulus G ′ and the temperature T is shown in FIG.

  The minimum value of the storage shear modulus G ′ in Example 1 was 24 Pa.

  The minimum value of the storage shear modulus G ′ in Example 8 was 2,000 Pa.

2. High-temperature and high-humidity reliability The sheet-coated element 4 was put into a high-temperature and high-humidity continuous lighting (0.77 A / mm ² ) test at 85 ° C./85% RH, and the change in the total luminous flux between the initial stage and after 1000 hours was evaluated Evaluation was based on the following criteria. The results are shown in Tables 1 and 2.
A: The ratio of the total luminous flux after 1000 hours to the initial total luminous flux was 90% or more.
X: The ratio of the total luminous flux after 1000 hours to the initial total luminous flux was less than 90%.

3. Total luminous flux The luminous efficiency of the optical semiconductor device 8 was measured by LED-Die-Prober (manufactured by MPI Co., Ltd .: LEDA-AS DP76 LED) and evaluated according to the following criteria. The results are shown in Tables 1 and 2.
A: Luminous efficiency is 150 lm / W or higher. O: Luminous efficiency is 149 lm / W or higher and lower than 150 lm / W.
4). Dimensions (thinning)
The thickness of the sheet covering element 4 was measured and evaluated according to the following criteria. The results are shown in Tables 1 and 2.
○: The thickness was 500 μm or less.
Δ: The thickness was over 500 μm.

5. Sealing property (1) Compressive elastic modulus The compressive elastic modulus at 25 ° C of the coated sheet 1 was measured with a precision load measuring device (MODEL-1605VCL: manufactured by AIKOH) and evaluated according to the following criteria.
○: Less than 10 MPa Δ: 10 MPa or more, 80 MPa or less ×: More than 80 MPa (2) Sealability to optical semiconductor element 5 Using the sheet covering element 4 in each example and each comparative example, FIG. 3, FIG. 8, an optical semiconductor element 4 shown in FIGS. 10 and 12, and an optical semiconductor device 8 shown in FIG.

Evaluation was based on the following criteria. The results are shown in Tables 1 and 2.
○: The sheet covering element 4 or the optical semiconductor device 8 was produced.
X: The sheet covering element 4 or the optical semiconductor device 8 could not be produced.

DESCRIPTION OF SYMBOLS 1 Cover sheet 2 Phosphor layer 3 Low refractive index layer 4 Sheet covering element 5 Optical semiconductor element 7 Light reflective layer 8 Optical semiconductor device 9 Substrate 41 First surface 42 Second surface T Thickness of low refractive index layer

Claims (9)

A coating layer for coating the optical semiconductor element;
A low refractive index layer that is disposed on the opposite side of the optical semiconductor element with respect to the coating layer and has a refractive index lower than the refractive index of the coating layer, in order in the thickness direction,
The coating layer contains a phenyl-based silicone resin,
The low refractive index layer has a thickness exceeding 10 μm, and contains a methyl silicone resin.   The covering sheet according to claim 1, wherein the low refractive index layer has a thickness of 100 μm or less.   The covering sheet according to claim 1, wherein the methyl silicone resin is a C stage.   The covering sheet according to any one of claims 1 to 3, wherein at least one surface in the thickness direction of the low refractive index layer has an uneven shape.   The said phenyl-type silicone resin is a B stage, The covering sheet as described in any one of Claims 1-4 characterized by the above-mentioned. The curve showing the relationship between the storage shear modulus G ′ and the temperature T obtained by measuring the viscoelasticity of the coating layer under the conditions of a frequency of 1 Hz and a heating rate of 20 ° C./min has a minimum value. ,
The temperature T at the minimum value is in the range of 40 ° C. or higher and 200 ° C. or lower,
6. The coated sheet according to claim 5, wherein the storage shear elastic modulus G ′ at the minimum value is in a range of 1,000 Pa or more and 90,000 Pa or less. The covering sheet according to any one of claims 1 to 4,
An optical semiconductor element covered with the covering layer of the covering sheet.   The sheet covering element according to claim 7, further comprising a light reflection layer disposed on a side of the optical semiconductor element when viewed from the thickness direction. The sheet covering element according to claim 7 or 8,
An optical semiconductor device comprising: a substrate on which the optical semiconductor element of the sheet covering element is mounted.

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