Thermosetting resin composition

Abstract

To provide sheet-like resin compositions for optical semiconductor elements, which have excellent sealability of the optical semiconductor elements, but have excellent heat resistance, and prevent breakage of sheets when separating adjacent optical semiconductor devices and also prevent the sticking between the sheets of the adjacent optical semiconductor devices.SOLUTION: A thermosetting resin composition 3 is a sheet-like thermosetting resin composition for sealing one or more optical semiconductor elements 6 disposed on a substrate 5. The thermosetting resin composition 3 may have a tensile storage elastic modulus E' of 0.1-10 MPa at 150°C after curing and may have a tensile storage elastic modulus E' of 10-1500 MPa at 25°C before curing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermosetting resin composition, and more specifically to a sheet-shaped thermosetting resin composition for encapsulating one or more optical semiconductor elements arranged on a substrate. [Background technology]

[0002] For example, a backlight used in a liquid crystal display device is known to have a structure in which a plurality of LEDs are arranged on a substrate and sealed with a sealing resin. A known method for sealing the plurality of LEDs collectively using the sealing resin is to pour liquid resin into the area where the plurality of LEDs are arranged, bury the plurality of LEDs, and then harden the liquid resin by applying heat or ultraviolet light.

[0003] However, the method of encapsulating optical semiconductor elements such as LEDs using a liquid resin has problems such as poor handling, such as dripping when the liquid resin is applied and adhesion to unintended areas. In response to this, it is conceivable that an encapsulating sheet having an encapsulating layer for encapsulating optical semiconductor elements, rather than using a liquid resin, can be used to encapsulate optical semiconductor elements easily and in a short time through a simple process. As such an encapsulating sheet, an encapsulant sheet for a light-emitting diode substrate containing a thermoplastic resin is known (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-9937 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the encapsulating sheet using a thermoplastic resin tends to have poor heat resistance because the thermoplastic resin may soften and melt near its melting point. Therefore, after an optical semiconductor element is encapsulated using the encapsulating sheet using a thermoplastic resin, there is a problem that the shape of the encapsulating sheet changes when, for example, an image display device to which the encapsulating sheet is applied generates heat or is heated when subjected to a reflow process after encapsulation.

[0006] Meanwhile, with the trend toward higher image quality, such as 4K and 8K, the demand for larger-screen image display devices is growing. Furthermore, the use of large-screen image display devices for signage, such as advertising displays and bulletin boards, outdoors and in public facilities, is also increasing. However, manufacturing large-screen image display devices poses problems of reduced yield and increased manufacturing costs. To manufacture large-screen image display devices at lower cost, tiling displays, in which multiple optical semiconductor devices, such as image display devices, are arranged in a tiled pattern, are being considered. When arranging multiple optical semiconductor devices in a tiled pattern, i.e., when tiling, if misalignment occurs between adjacent optical semiconductor devices or if rearrangement is required, positional correction is performed.

[0007] Here, when tiling optical semiconductor devices in which optical semiconductor elements are encapsulated with an encapsulating sheet, it is necessary to temporarily separate adjacent optical semiconductor devices in order to correct their positions during tiling. However, when separating them, the encapsulating sheet of one optical semiconductor device and the encapsulating sheet of the other adjacent optical semiconductor device may come into close contact with each other and attract each other, which may cause defects such as defects in the encapsulating sheet of one optical semiconductor device or transfer and adhesion of a part of the encapsulating sheet to the other optical semiconductor device.

[0008] The present invention was conceived under these circumstances, and its object is to provide a sheet-like resin composition for encapsulating optical semiconductor elements that has excellent encapsulation properties for optical semiconductor elements, excellent heat resistance, and is less likely to cause damage to the sheet or adhesion of sheets of adjacent optical semiconductor devices when separating the adjacent optical semiconductor devices. [Means for solving the problem]

[0009] As a result of intensive research to achieve the above object, the present inventors have found that, as a sheet-shaped resin composition for encapsulating optical semiconductor elements, a thermosetting resin composition having a tensile storage modulus E' at 150°C after curing within a specific range, or a thermosetting resin composition having a tensile storage modulus E' at 25°C before curing within a specific range, provides excellent encapsulation of optical semiconductor elements while also having excellent heat resistance, and is less likely to cause damage to the sheet or adhesion of the sheets of adjacent optical semiconductor devices when separating them. The present invention was completed based on these findings.

[0010] That is, one embodiment of the present invention is a sheet-shaped thermosetting resin composition for encapsulating one or more optical semiconductor elements arranged on a substrate, comprising: The thermosetting resin composition has a tensile storage modulus E' at 150°C of 0.1 to 10 MPa after curing.

[0011] The thermosetting resin composition has thermosetting properties, so that a sheet-shaped thermosetting resin composition can be attached to a substrate equipped with an optical semiconductor element, embedding the optical semiconductor element in the thermosetting resin composition, and then curing the composition by heating to encapsulate the optical semiconductor element. Furthermore, the thermosetting resin composition is resistant to softening and melting due to heat after thermal curing, and therefore has excellent heat resistance. Furthermore, as described above, the 150°C tensile storage modulus E' of the thermosetting resin composition after curing is 0.1 to 10 MPa. Having a 150°C tensile storage modulus E' of 0.1 MPa or more allows the thermosetting resin composition to have a certain degree of hardness after curing, resulting in low adhesion between the side surfaces of adjacent optical semiconductor devices in a tiling state. Therefore, when adjacent optical semiconductor devices are separated from each other, damage to the sheet on the side surfaces of the optical semiconductor device and adhesion of the sheets of adjacent optical semiconductor devices are unlikely to occur. Furthermore, since the tensile storage modulus E' at 150°C is 10 MPa or less, when an optical semiconductor element is encapsulated, the difference in the linear expansion coefficient between the cured product of the thermosetting resin composition and the substrate is small, which makes it less likely for the substrate carrying the optical semiconductor element to warp, resulting in excellent encapsulation properties for the optical semiconductor element.

[0012] The thermosetting resin composition preferably has a glass transition temperature of 20 to 100° C. after curing. When the glass transition temperature is 20° C. or higher, the surface has excellent scratch resistance. When the glass transition temperature is 100° C. or lower, the substrate is less likely to warp after thermal curing of the thermosetting resin composition, and the sealing performance of the optical semiconductor element is excellent.

[0013] The thermosetting resin composition preferably has a tan δ of 0.7 to 1.5 at the glass transition temperature after curing. When the tan δ is 0.7 or more, the substrate is less likely to warp after thermal curing of the thermosetting resin composition, resulting in excellent sealing properties for optical semiconductor elements. When the tan δ is 1.5 or less, the surface has excellent scratch resistance.

[0014] Another embodiment of the present invention is a sheet-shaped thermosetting resin composition for encapsulating one or more optical semiconductor elements arranged on a substrate, comprising: The thermosetting resin composition has a tensile storage modulus E' at 25°C of 10 to 1500 MPa.

[0015] The thermosetting resin composition has thermosetting properties, allowing a sheet-like thermosetting resin composition to be attached to a substrate equipped with an optical semiconductor element, embedding the optical semiconductor element in the thermosetting resin composition, and then curing the composition by heating to encapsulate the optical semiconductor element. Furthermore, the thermosetting resin composition is resistant to softening and melting due to heat after thermal curing, resulting in excellent heat resistance. Furthermore, as described above, the 25°C tensile storage modulus E' of the thermosetting resin composition is 10 to 1500 MPa. Having a 25°C tensile storage modulus E' of 10 MPa or more allows the thermosetting resin composition to have a certain degree of hardness after curing, resulting in low adhesion between the side surfaces of adjacent optical semiconductor devices in a tiling state. This reduces the likelihood of sheet damage on the side surfaces of the optical semiconductor devices or adhesion of the sheets of adjacent optical semiconductor devices when separating the adjacent optical semiconductor devices. Furthermore, the thermosetting resin composition has excellent machinability when punching or otherwise processing the composition before thermal curing. Since the tensile storage modulus E' at 25°C is 1500 MPa or less, when an optical semiconductor element is encapsulated, the difference in the linear expansion coefficient between the cured product of the thermosetting resin composition and the substrate is small, which makes it difficult for the substrate to warp and provides excellent encapsulation of the optical semiconductor element.In addition, since the composition has appropriate flexibility, it is less likely to crack and is easy to handle.

[0016] The thermosetting resin composition preferably has a 140°C shear loss modulus G'' of 1 to 20 KPa before curing. If the 140°C shear loss modulus G'' is 1 KPa or more, when the thermosetting resin composition is attached to an optical semiconductor element by thermal lamination and when heated in the thermal curing step, the optical semiconductor element can be appropriately embedded, the thermosetting resin composition is less likely to extrude, and the encapsulation of the optical semiconductor element is superior. If the 140°C shear loss modulus G'' is 20 KPa or less, when the thermosetting resin composition is attached to an optical semiconductor element by thermal lamination and when heated in the thermal curing step, the optical semiconductor element can be sufficiently embedded, and the encapsulation of the optical semiconductor element is superior.

[0017] The thermosetting resin composition preferably contains an acrylic resin and inorganic particles. This configuration makes it more difficult for the substrate to warp after the thermosetting resin composition is cured. In addition, excellent dicing properties and high heat resistance reliability are ensured.

[0018] The thermosetting resin composition preferably has a haze value of 1.0% or less after heat curing. When the haze value is 1.0% or less, the composition has excellent light transmittance after heat curing, which is preferable for use in image display devices.

[0019] The ratio of the light transmittance of the thermosetting resin composition after curing to the light transmittance before curing [after curing / before curing] is preferably 0.95 or more. When the ratio is 0.95 or more, coloring such as whitening or yellowing is unlikely to occur before and after thermal curing, and the light transmittance is excellent, making it preferable for use in image display devices.

[0020] The present invention also provides an optical semiconductor device comprising a substrate, an optical semiconductor element disposed on the substrate, and a cured product formed by curing the thermosetting resin composition to encapsulate the optical semiconductor element. Such an optical semiconductor device has excellent encapsulation properties for the optical semiconductor element and excellent heat resistance, and is less likely to suffer damage to the sheet or adhesion of the sheets of adjacent optical semiconductor devices when the sheets are separated from each other.

[0021] The optical semiconductor device may be a backlight for a liquid crystal display screen, or may be a self-luminous display device.

[0022] The present invention also provides an image display device including the above backlight and a display panel.

[0023] The present invention also provides an image display device including the above-described self-luminous display device. [Effects of the Invention]

[0024] The thermosetting resin composition of the present invention has excellent heat resistance while being excellent in sealing optical semiconductor elements. Therefore, even when an image display device using the sheet-shaped thermosetting resin composition generates heat or is heated during a reflow process after sealing, the shape is unlikely to change. Furthermore, the sheet after sealing can be subjected to a heating process such as a reflow process, improving the process flexibility when manufacturing an optical semiconductor device.

[0025] Furthermore, the thermosetting resin composition of the present invention makes it possible to prevent damage to the sheet or adhesion of the sheets of adjacent optical semiconductor devices when separating adjacent optical semiconductor devices. Therefore, after tiling the optical semiconductor devices, if misalignment or rearrangement occurs between adjacent optical semiconductor devices, the position can be easily corrected without any problems, reducing loss of optical semiconductor devices and enabling the economical production of attractive displays. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view showing one embodiment of a sheet for encapsulating an optical semiconductor element comprising a thermosetting resin composition of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of an optical semiconductor device using the optical semiconductor element encapsulation sheet shown in FIG. [Figure 3] 3 is an external view showing one embodiment of an optical semiconductor device produced by tiling the optical semiconductor device shown in FIG. 2. FIG. [Figure 4] 1A and 1B are cross-sectional views illustrating a filling step in one embodiment of a method for manufacturing an optical semiconductor device. [Figure 5] 5 is a cross-sectional view showing a laminate obtained after the embedding step shown in FIG. 4. [Figure 6] 6 is a cross-sectional view showing a laminate obtained by carrying out a heating step on the laminate shown in FIG. 5. [Figure 7] 7 is a cross-sectional view showing a dicing position in a dicing step of the laminate shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0027] [Thermosetting resin composition] The thermosetting resin composition of the present invention is a sheet-shaped thermosetting resin composition for encapsulating one or more optical semiconductor elements arranged on a substrate. In this specification, "encapsulating an optical semiconductor element" refers to embedding at least a portion of the optical semiconductor element in the thermosetting resin composition. Because the thermosetting resin composition has thermosetting properties, the sheet-shaped thermosetting resin composition can be attached to a substrate equipped with an optical semiconductor element, embedding the optical semiconductor element in the thermosetting resin composition, and then curing the composition by heating to encapsulate the optical semiconductor element. Furthermore, the thermosetting resin composition is resistant to softening and melting due to heat after thermal curing, and therefore has excellent heat resistance.

[0028] The 150°C tensile storage modulus E' of the thermosetting resin composition after curing is preferably 0.1 to 10 MPa, more preferably 0.15 to 5 MPa. When the 150°C tensile storage modulus E' is 0.1 MPa or more, the thermosetting resin composition has a certain degree of hardness after curing, and the adhesion between the side surfaces of adjacent optical semiconductor devices in a tiling state is low, so that when adjacent optical semiconductor devices are separated, damage to the sheet on the side surfaces of the optical semiconductor devices and adhesion of the sheets of adjacent optical semiconductor devices are unlikely to occur. When the 150°C tensile storage modulus E' is 10 MPa or less, the difference in linear expansion coefficient between the cured product of the thermosetting resin composition and the substrate is small when an optical semiconductor element is encapsulated, so that warping of the substrate is unlikely to occur, resulting in excellent encapsulation of the optical semiconductor element.

[0029] The 25°C tensile storage modulus E' of the thermosetting resin composition (before curing) is preferably 10 to 1500 MPa, more preferably 20 to 1000 MPa. Having a 25°C tensile storage modulus E' of 10 MPa or more allows the thermosetting resin composition to have a certain degree of hardness after curing, resulting in low adhesion between the side surfaces of adjacent optical semiconductor devices in a tiling state. This reduces the likelihood of sheet damage on the side surfaces of the optical semiconductor devices or adhesion between adjacent optical semiconductor devices when separating the adjacent optical semiconductor devices. Furthermore, the thermosetting resin composition exhibits excellent machinability when punched before thermal curing. Having a 25°C tensile storage modulus E' of 1500 MPa or less reduces the difference in linear expansion coefficient between the cured product of the thermosetting resin composition and the substrate when encapsulating an optical semiconductor element, reducing the likelihood of substrate warpage and providing excellent encapsulation of the optical semiconductor element. Furthermore, due to the moderate flexibility, the thermosetting resin composition is less likely to chip or crack during handling, providing excellent handleability.

[0030] The glass transition temperature (Tg) of the thermosetting resin composition after curing is preferably 20 to 100°C, more preferably 20 to 60°C. When the Tg is 20°C or higher, the surface has excellent scratch resistance. When the Tg is 100°C or lower, the thermosetting resin composition is less likely to warp after thermal curing, and has excellent sealing properties for optical semiconductor elements. The glass transition temperature can be calculated using a dynamic viscoelasticity measurement (DMA) device.

[0031] The thermosetting resin composition preferably has a tan δ of 0.7 to 1.5, more preferably 1.0 to 1.5, at the glass transition temperature after curing. When the tan δ is 0.7 or more, the thermosetting resin composition is less likely to warp after thermal curing, resulting in excellent sealing properties for optical semiconductor elements. When the tan δ is 1.5 or less, the surface has excellent scratch resistance. The tan δ can be calculated using a dynamic viscoelasticity measurement (DMA) device.

[0032] The 140°C shear loss modulus G'' of the thermosetting resin composition (before curing) is preferably 1 to 20 KPa, and more preferably 10 to 20 KPa. If the 140°C shear loss modulus G'' is 1 KPa or more, when the thermosetting resin composition is attached to an optical semiconductor element by thermal lamination and when heated in the thermal curing step, the optical semiconductor element can be appropriately embedded, and the thermosetting resin composition is less likely to extrude, resulting in better encapsulation of the optical semiconductor element. If the 140°C shear loss modulus G'' is 20 KPa or less, when the thermosetting resin composition is attached to an optical semiconductor element by thermal lamination and when heated in the thermal curing step, the optical semiconductor element can be sufficiently embedded, resulting in better encapsulation of the optical semiconductor element.

[0033] The shear loss modulus can be obtained by measuring a thermosetting resin composition punched into a cylindrical shape of φ8 mm × 300 μm in shear mode at a frequency of 1 Hz and calculating the shear loss modulus at 140° C. The measurement of the shear loss modulus and the analysis of the measured values can be performed using a solid viscoelasticity measuring device (product name "HAAKE MARSIII Rheometer", manufactured by Thermo Scientific).

[0034] The haze value of the thermosetting resin composition is preferably 1.0% or less, more preferably 0.8% or less. The haze value may be 0.1% or more. When the haze value is within the above range, the composition exhibits excellent light transmittance after thermal curing, making it preferable for use in image display devices. Furthermore, the thermosetting resin composition can be produced with a simple configuration, for example, by not incorporating a curing agent or by minimizing the incorporation rate of a curing agent, making it possible to achieve the above haze value. The haze value can be measured, for example, using a haze meter in accordance with JIS K 7136. Furthermore, the haze value of the thermosetting resin composition after thermal curing is preferably within the above range. When the haze value after thermal curing is within the above range, the composition exhibits excellent light transmittance, making it preferable for use in image display devices.

[0035] The thermosetting resin composition preferably has a light transmittance of 85% or more at a wavelength of 400 nm, and more preferably 90% or more. A light transmittance of 85% or more provides excellent light transmittance, making it suitable for use in image display devices. Furthermore, the thermosetting resin composition can be produced with a simple configuration, for example, by not incorporating a curing agent or by minimizing the incorporation rate of a curing agent. Furthermore, it is preferable that the thermosetting resin composition, after curing, has a light transmittance of 400 nm after storage at 125°C for 1,000 hours within the above range.

[0036] The ratio of the light transmittance of the thermosetting resin composition after curing to the light transmittance before curing [after curing / before curing] is preferably 0.95 or more. When the ratio is 0.95 or more, coloring such as whitening or yellowing is unlikely to occur before and after thermal curing, and the light transmittance is excellent, making it preferable for use in image display devices.

[0037] The thermosetting resin composition preferably contains at least an acrylic resin as an organic component. The content of the acrylic resin in the organic components is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, relative to the total amount (100% by mass) of the organic components in the thermosetting resin composition. When the content is 85% by mass or more, the thermosetting resin composition has excellent light transmittance after thermal curing. The content may be 100% by mass.

[0038] The acrylic resin is a resin containing a structural unit derived from an acrylic monomer (a monomer component having a (meth)acryloyl group or a structure convertible thereto in the molecule) as a structural unit of the resin (polymer). Only one type of the acrylic resin may be used, or two or more types may be used.

[0039] The acrylic resin is preferably a resin containing the most structural units derived from (meth)acrylic acid esters by mass. In this specification, "(meth)acrylic" refers to "acrylic" and / or "methacrylic" (either one or both of "acrylic" and "methacrylic"), and the same applies to other terms.

[0040] The thermosetting resin composition preferably contains a thermosetting resin from the viewpoint of having thermosetting properties. As the thermosetting resin, a known or commonly used thermosetting resin can be used, for example, a resin having a thermosetting functional group. Among them, an acrylic resin having a thermosetting functional group (a thermosetting functional group-containing acrylic resin) is preferred as the thermosetting resin.

[0041] Examples of the thermosetting functional group include epoxy group-containing groups such as glycidyl groups, carboxy groups, hydroxy groups, isocyanate groups, and aziridyl groups. Among these, epoxy group-containing groups are preferred, and glycidyl groups are more preferred. That is, as an acrylic resin having a thermosetting functional group, a glycidyl group-containing acrylic resin is particularly preferred. The thermosetting functional group may be used alone or in combination of two or more.

[0042] The acrylic resin having a thermosetting functional group preferably contains a structural unit derived from a monomer having a thermosetting functional group, and more preferably contains a structural unit derived from an acrylic monomer having a thermosetting functional group (a thermosetting functional group-containing acrylic monomer). Examples of the monomer having a thermosetting functional group include epoxy group-containing (meth)acrylic esters such as glycidyl group-containing (meth)acrylic esters, carboxy group-containing monomers, acid anhydride group-containing monomers, and hydroxy group-containing (meth)acrylic esters.

[0043] Examples of the glycidyl group-containing (meth)acrylic acid ester include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate.

[0044] Examples of the carboxy group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. Examples of the acid anhydride group-containing monomer include maleic anhydride, itaconic anhydride, etc.

[0045] Examples of the hydroxy group-containing (meth)acrylic acid ester include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

[0046] Among the thermosetting functional group-containing acrylic monomers, epoxy group-containing (meth)acrylic esters are preferred, and glycidyl group-containing (meth)acrylic esters are more preferred. When the acrylic resin contains a structural unit derived from a glycidyl group-containing (meth)acrylic ester, the glycidyl group acts as a thermosetting functional group, and even without a curing agent, the reaction of the glycidyl group proceeds through thermal curing, resulting in the curing of the thermosetting resin composition. Therefore, the thermosetting resin composition has appropriate flexibility after thermal curing and is superior in encapsulating optical semiconductor elements.

[0047] The content of the structural units derived from the glycidyl group-containing (meth)acrylic acid ester is preferably 5 to 50 mass %, more preferably 6 to 45 mass %, relative to the total amount (100 mass %) of all structural units of the glycidyl group-containing acrylic resin. When the content is within the above range, the thermosetting resin composition has appropriate flexibility after thermal curing and is superior in encapsulating properties for optical semiconductor elements.

[0048] The thermosetting functional group-containing acrylic resin may contain a constituent unit derived from a monomer other than the thermosetting functional group-containing monomer. Examples of the other monomer include (meth)acrylic acid esters other than the thermosetting functional group-containing acrylic monomer. The other monomers may be used singly or in combination of two or more.

[0049] Examples of the other (meth)acrylic acid esters include hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group. Examples of the hydrocarbon group-containing (meth)acrylic acid esters in the hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group include (meth)acrylic acid alkyl esters having a linear or branched aliphatic hydrocarbon group, (meth)acrylic acid esters having an alicyclic hydrocarbon group such as (meth)acrylic acid cycloalkyl esters, and (meth)acrylic acid esters having an aromatic hydrocarbon group such as (meth)acrylic acid aryl esters. The hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group may be used singly or in combination of two or more.

[0050] Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and methyl (meth)acrylate. Examples of the acrylate include isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

[0051] Among the above-mentioned (meth)acrylic acid alkyl esters, (meth)acrylic acid alkyl esters having a linear or branched aliphatic hydrocarbon group with a carbon number of 1 to 20 (preferably 1 to 14, more preferably 2 to 10, and even more preferably 2 to 8) are preferred. When the carbon number is within the above range, the flexibility of the thermosetting group-containing acrylic resin during heat curing tends to be more appropriate, and embeddability is further improved.

[0052] Examples of the (meth)acrylic acid ester having an alicyclic hydrocarbon group include (meth)acrylic acid esters having a monocyclic aliphatic hydrocarbon ring such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate; (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; and (meth)acrylic acid esters having a tricyclic or higher aliphatic hydrocarbon ring such as dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

[0053] Examples of the (meth)acrylic acid ester having an aromatic hydrocarbon group include (meth)acrylic acid phenyl ester and (meth)acrylic acid benzyl ester.

[0054] Examples of hydrocarbon group-containing (meth)acrylic acid esters having alkoxy groups include those in which one or more hydrogen atoms in the hydrocarbon group of the above hydrocarbon group-containing (meth)acrylic acid esters have been substituted with alkoxy groups, such as 2-methoxymethyl ester, 2-methoxyethyl ester, and 2-methoxybutyl ester of (meth)acrylic acid.

[0055] In order to properly exhibit basic properties such as adhesiveness and adhesion to optical semiconductor elements due to the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group in the thermosetting resin composition, the proportion of the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group to all structural units of the thermosetting functional group-containing acrylic resin is preferably 50 to 95 mass %, more preferably 55 to 94 mass %, relative to the total amount (100 mass %) of all structural units of the thermosetting functional group-containing acrylic resin.

[0056] Examples of the other monomer components include polar group-containing monomers such as sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and nitrogen atom-containing monomers. Examples of the sulfonic acid group-containing monomers include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of the phosphoric acid group-containing monomers include 2-hydroxyethyl acryloyl phosphate. Examples of the nitrogen atom-containing monomers include morpholino group-containing monomers such as (meth)acryloylmorpholine, cyano group-containing monomers such as (meth)acrylonitrile, and amide group-containing monomers such as (meth)acrylamide.

[0057] The thermosetting functional group-containing acrylic resin may contain a structural unit derived from a polyfunctional (meth)acrylate copolymerizable with the monomer components constituting the acrylic resin to form a crosslinked structure in the polymer skeleton. Examples of the polyfunctional (meth)acrylate include hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. The polyfunctional (meth)acrylate may be used alone or in combination of two or more.

[0058] The thermosetting functional group-containing acrylic resin is obtained by polymerizing the above-mentioned various monomer components. The polymerization method is not particularly limited, but examples thereof include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization by active energy ray irradiation (active energy ray polymerization). The obtained acrylic resin may be any of random copolymers, block copolymers, graft copolymers, etc.

[0059] The weight-average molecular weight of the glycidyl group-containing acrylic resin is preferably 2,000 to 400,000. When the weight-average molecular weight is within the above range, the embedding property of an optical semiconductor element is superior. The weight-average molecular weight is measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

[0060] The glycidyl group-containing acrylic resin preferably contains one having a weight average molecular weight of 30,000 to 300,000, from the viewpoint of having a certain degree of hardness after curing of the thermosetting resin composition and reducing adhesion between the side surfaces of an optical semiconductor device having cut side surfaces. Furthermore, the glycidyl group-containing acrylic resin may further contain one having a weight average molecular weight of 2,000 to 20,000 (preferably 2,000 to 10,000), from the viewpoint of reducing the loss modulus before curing and further improving embeddability.

[0061] The content of the glycidyl group-containing acrylic resin in the organic component is preferably 40% by mass or more (for example, 40 to 100% by mass), more preferably 50% by mass or more, and even more preferably 60% by mass or more, relative to the total amount (100% by mass) of the organic components in the thermosetting resin composition. When the content is 40% by mass or more, the embeddability of the optical semiconductor element is superior.

[0062] The thermosetting resin composition preferably contains a component having a functional group (second functional group) that can react with the thermosetting functional group (first functional group) in the thermosetting functional group-containing acrylic resin by heat. The second functional group is also a thermosetting functional group. In this case, the reaction between the first functional group and the second functional group during heating of the thermosetting resin composition further accelerates the curing of the thermosetting resin composition.

[0063] The component having the second functional group may be a thermosetting functional group-containing acrylic resin other than the thermosetting functional group-containing acrylic resin having the first functional group, or may be another component having a second functional group. Only one type of component having the second functional group may be used, or two or more types may be used.

[0064] Examples of combinations of the first functional group and the second functional group include a carboxy group and an epoxy group, an epoxy group and a carboxy group, a carboxy group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, an isocyanate group and a hydroxy group, etc. The combinations may be of only one type or two or more types.

[0065] When the thermosetting resin composition contains the glycidyl group-containing acrylic resin, the component having the second functional group preferably contains a component having a functional group reactive with the glycidyl group. Examples of the functional group reactive with the glycidyl group include a carboxy group, an aziridyl group, and a hydroxy group. Among these, a carboxy group and a hydroxy group are preferred. As the hydroxy group, a silanol group is preferred from the viewpoint of high acidity and excellent reactivity with epoxy groups.

[0066] The component having a carboxy group is preferably the organic component, more preferably a carboxy group-containing acrylic resin. The inclusion of the carboxy group-containing acrylic resin facilitates the reaction between the glycidyl group and the carboxy group in the glycidyl group-containing acrylic resin, even without a curing agent, and provides superior sealing of optical semiconductor elements. Furthermore, the surface scratch resistance is further improved.

[0067] The carboxyl group-containing acrylic resin preferably contains a structural unit derived from a carboxyl group-containing monomer, more preferably a structural unit derived from a carboxyl group-containing acrylic monomer, such as acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, or crotonic acid.

[0068] The content of the structural units derived from the carboxyl group-containing acrylic monomer is preferably 1 to 50 mass %, more preferably 10 to 40 mass %, relative to the total amount (100 mass %) of all structural units of the carboxyl group-containing acrylic resin. When the content is within the above range, the thermosetting resin composition has appropriate flexibility after thermal curing and is superior in encapsulating properties for optical semiconductor elements.

[0069] The carboxyl group-containing acrylic resin may contain a constituent unit derived from a monomer other than the carboxyl group-containing monomer. Examples of the other monomer include (meth)acrylic acid esters other than the thermosetting functional group-containing acrylic monomer, the polar group-containing monomers, and the polyfunctional monomers. The other monomers may be used singly or in combination of two or more.

[0070] Examples of the other (meth)acrylic acid esters include the hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group. As the (meth)acrylic acid alkyl esters in the hydrocarbon group-containing (meth)acrylic acid esters which may have an alkoxy group, (meth)acrylic acid alkyl esters having a linear or branched aliphatic hydrocarbon group having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 1 to 10, and even more preferably 1 to 8) are preferred. When the carbon number is within the above range, the flexibility of the thermosetting group-containing acrylic resin is more likely to be appropriate, and the embeddability is further improved.

[0071] In order to adequately exhibit the basic properties of the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group, such as adhesiveness and adhesion to optical semiconductor elements, in the thermosetting resin composition, the proportion of the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group relative to the total amount (100% by mass) of all structural units of the carboxy group-containing acrylic resin is preferably 50 to 95% by mass, and more preferably 60 to 90% by mass.

[0072] The weight-average molecular weight of the carboxyl group-containing acrylic resin is preferably 1,000 to 200,000, and more preferably 3,000 to 100,000. When the weight-average molecular weight is within the above range, the embedding property of the optical semiconductor device is superior. The weight-average molecular weight is measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

[0073] When the carboxyl group-containing acrylic resin is contained, the content of the carboxyl group-containing acrylic resin in the organic components is preferably 5 to 60 mass %, more preferably 10 to 50 mass %, and even more preferably 25 to 45 mass %, relative to the total amount (100 mass %) of the organic components in the thermosetting resin composition. When the content is within the above range, the thermosetting resin composition has better thermosetting properties and better surface scratch resistance.

[0074] The content of the organic component in the thermosetting resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 65% by mass or more, based on the total amount (100% by mass) of the thermosetting resin composition. When the content is 50% by mass or more, the thermosetting resin composition has excellent flexibility and excellent embeddability for optical semiconductor elements. The content may be 100% by mass.

[0075] The thermosetting resin composition preferably contains inorganic particles. When the thermosetting resin composition contains the inorganic particles, warping is less likely to occur after curing. In addition, excellent dicing properties are achieved, and high heat resistance reliability is ensured. The inorganic particles may have various shapes, such as spherical, acicular, or flake-like. Only one type of inorganic particle may be used, or two or more types may be used.

[0076] The inorganic particles are preferably inorganic particles having silanol groups, more preferably silica particles. When the inorganic particles having silanol groups (particularly silica particles) are contained, the inorganic particles correspond to the other component having the second functional group, and the silanol groups act as thermosetting functional groups. The reaction between the glycidyl groups and the silanol groups in the glycidyl group-containing acrylic resin proceeds more easily even without the addition of a curing agent. Furthermore, the thermosetting resin composition has a certain degree of hardness before thermal curing, resulting in excellent sealing properties for optical semiconductor elements. Furthermore, warping of the substrate is suppressed after sealing, resulting in even better sealing properties.

[0077] The inorganic particles preferably have an average particle size of 50 nm or less (e.g., 1 to 50 nm), more preferably 30 nm or less (e.g., 3 to 30 nm). When the average particle size is 50 μm or less, the total surface area of the inorganic particles is sufficiently large. Therefore, when the inorganic particles have silanol groups, the amount of silanol groups increases, resulting in higher reactivity with epoxy groups. Furthermore, excellent light transmittance and high heat resistance reliability are ensured after curing of the thermosetting resin composition. The average particle size of the filler can be determined, for example, using a photometric particle size distribution analyzer (e.g., product name "LA-910," manufactured by Horiba, Ltd.).

[0078] When the thermosetting resin composition contains the inorganic particles, the content of the inorganic particles is preferably 1 to 50 parts by mass, more preferably 5 to 45 parts by mass, per 100 parts by mass of the total amount of the organic components. When the content is 1 part by mass or more, the thermosetting resin composition has better thermosetting properties. When the content is 50 parts by mass or less, the thermosetting resin composition has better flexibility, better embeddability for optical semiconductor elements, and better surface scratch resistance.

[0079] The thermosetting resin composition may contain other components in addition to the above-mentioned various components, as long as the effects of the present invention are not impaired. Examples of such other components include resins other than acrylic resins, crosslinking accelerators, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, antioxidants, other fillers (organic fillers, etc.), colorants (pigments, dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, UV absorbers, polymerization inhibitors, granular materials, foil-like materials, etc. Only one of the above other components may be used, or two or more may be used.

[0080] The colorant is preferably a black colorant. Known or commonly used colorants (pigments, dyes, etc.) for producing black can be used as the black colorant. Examples of the black colorant include carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, pine soot, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complexes, anthraquinone-based colorants, and zirconium nitride. Only one type of black colorant may be used, or two or more types may be used. Alternatively, a colorant that functions as a black colorant may be used by combining colorants that produce colors other than black.

[0081] The content of the curing agent that promotes the reaction of thermosetting functional groups or forms crosslinks in the thermosetting resin composition is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and particularly preferably substantially none, relative to the total amount (100% by mass) of the thermosetting resin composition. Even without a curing agent, the glycidyl group-containing acrylic resin undergoes a reaction of the glycidyl group upon thermal curing, curing the thermosetting resin composition. Therefore, when the content is 10% by mass or less, the thermosetting resin composition has appropriate flexibility after thermal curing and exhibits excellent encapsulation of optical semiconductor elements. Furthermore, the composition exhibits excellent light transmittance.

[0082] Examples of the curing agent include those that have the effect of accelerating the thermal curing of glycidyl groups, and specific examples include epoxy resins, phenolic resins, amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, and thermosetting polyimide resins.

[0083] The Shore D hardness of the thermosetting resin composition after thermal curing is preferably 50 to 100, more preferably 60 to 97, and even more preferably 80 to 95. When the Shore D hardness is within the above range, the surface has excellent scratch resistance. The Shore D hardness can be measured in accordance with ASTM D-2240.

[0084] When the thermosetting resin composition is bonded to a 100 μm-thick wafer and thermally cured, the amount of warpage of the wafer after thermal curing relative to before thermal curing is preferably 4 mm or less, more preferably 3 mm or less, and even more preferably 1 mm or less. If the amount of warpage is 4 mm or less, the sealing ability for optical semiconductor elements is superior after the thermal curing tensile storage modulus E is adjusted. The amount of warpage is determined by bonding the sheet-like thermosetting resin composition to a 100 μm-thick wafer, setting the warpage of the wafer before thermal curing to 0 mm, and measuring the amount of warpage of the wafer when the thermosetting resin composition is thermally cured.

[0085] The thermosetting resin composition may be provided on the surface of a substrate. In this case, the substrate serves as a support for the thermosetting resin composition, and the provision of the substrate makes the thermosetting resin composition easy to handle. Note that a sheet comprising the substrate and the thermosetting resin composition provided on one surface of the substrate may be referred to as a sheet for encapsulating optical semiconductor elements.

[0086] The thermosetting resin composition may also have a release liner on at least one surface thereof (for example, on the surface opposite to the substrate when the substrate is present). The release liner is used as a protective material for the thermosetting resin composition and is peeled off when the optical semiconductor element is encapsulated using the thermosetting resin composition. However, the release liner is not necessarily provided.

[0087] The release liner is an element for covering and protecting the surface of the thermosetting resin composition, and is peeled off from the sheet when the thermosetting resin composition is to be attached to a substrate on which an optical semiconductor element is disposed.

[0088] Examples of the release liner include polyethylene terephthalate (PET) film, polyethylene film, polypropylene film, plastic films and papers whose surfaces are coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent.

[0089] The thickness of the release liner is, for example, 10 to 200 μm, preferably 15 to 150 μm, and more preferably 20 to 100 μm. When the thickness is 10 μm or more, the release liner is less likely to break due to cuts during processing. When the thickness is 200 μm or less, the release liner is more easily peeled from the thermosetting resin composition during use.

[0090] [Optical semiconductor element encapsulation sheet] The optical semiconductor element encapsulation sheet includes the substrate and the thermosetting resin composition in a sheet form provided on one surface of the substrate.

[0091] An embodiment of the optical semiconductor element encapsulation sheet will be described below. FIG. 1 is a cross-sectional view showing an embodiment of the optical semiconductor element encapsulation sheet comprising the thermosetting resin composition of the present invention. As shown in FIG. 1, the optical semiconductor element encapsulation sheet 1 can be used to encapsulate one or more optical semiconductor elements arranged on a substrate, and comprises a substrate 2, a sheet-like thermosetting resin composition 3, and a release liner 4. The thermosetting resin composition 3 is provided on one side of the substrate 2. The release liner 4 is attached to the surface of the thermosetting resin composition 3 (the surface opposite to the side having the substrate 2). In other words, the optical semiconductor element encapsulation sheet 1 comprises the substrate 2, the thermosetting resin composition 3, and the release liner 4 in this order. The substrate 2 is a multilayer structure comprising an optical film 21 and a plastic film 23, and the optical film 21 and the plastic film 23 are attached to each other via an adhesive layer 22.

[0092] <Base material part> The substrate may be a single layer, or may be multiple layers having the same or different compositions, thicknesses, etc. When the substrate is multiple layers, each layer may be bonded to another layer such as an adhesive layer. Note that the substrate layer used in the substrate is the part that is attached to the substrate including the optical semiconductor element together with the thermosetting resin composition when the optical semiconductor element is encapsulated using the thermosetting resin composition, and the "substrate" does not include a release liner that is peeled off when the thermosetting resin composition is used (attached) or a surface protection film that merely protects the surface of the substrate.

[0093] Examples of the substrate layer constituting the substrate part include glass and plastic substrates (particularly, plastic films). Examples of resins constituting the plastic substrate include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, very low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypropylene, polybutene, polymethylpentene, ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-propylene copolymer, cyclic olefin polymer, ethylene-butene copolymer, ethylene-hexene copolymer, etc. Examples of suitable resins include polyolefin resins, polyurethanes, polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT), polycarbonates, polyimide resins, polyether ether ketones, polyetherimides, polyamides such as aramids and wholly aromatic polyamides, polyphenyl sulfides, fluororesins, polyvinyl chloride, polyvinylidene chloride, cellulose resins such as triacetyl cellulose (TAC), silicone resins, acrylic resins such as polymethyl methacrylate (PMMA), polysulfones, polyarylates, and polyvinyl acetates. These resins may be used singly or in combination.

[0094] The substrate layer may be any of various optical films such as an antireflection (AR) film, a polarizing plate, a retardation plate, etc. When the substrate part has an optical film, the substrate layer can be applied directly to an optical member.

[0095] The plastic film preferably contains a polyester resin and / or a polyimide resin as the main component (the component with the highest mass ratio among the constituent resins). This configuration provides the substrate with excellent heat resistance, suppresses thermal expansion of the substrate in high-temperature environments, and improves dimensional stability. Furthermore, the substrate can be given rigidity as a sheet, improving handling and retention.

[0096] The thickness of the plastic film is preferably 20 to 200 μm, more preferably 40 to 150 μm. When the thickness is 20 μm or more, the supportability and handleability of the optical semiconductor element encapsulation sheet are further improved. When the thickness is 200 μm or less, the optical semiconductor device can be made thinner.

[0097] The substrate preferably includes a plastic film mainly composed of a polyester resin and / or a polyimide resin, and an optical film. Optical films such as polarizing plates generally tend to be poor in supportability and handling, so by using them in combination with the plastic film, the advantages of both can be utilized. In this case, it is particularly preferred that the plastic film is on the side of the substrate that contains the thermosetting resin composition.

[0098] The substrate preferably includes a layer having antiglare and / or antireflection properties. The layer having antiglare and / or antireflection properties can be obtained as the antiglare-treated layer or antireflection-treated layer by, for example, performing an antiglare treatment and / or an antireflection treatment on at least one surface of the substrate layer. The antiglare-treated layer and the antireflection-treated layer may be the same layer or different layers. The antiglare treatment and the antireflection treatment can be performed by known or conventional methods.

[0099] The surface of the substrate on the side where the thermosetting resin composition is provided may be subjected to surface treatments such as physical treatments such as corona discharge treatment, plasma treatment, sand matting treatment, ozone exposure treatment, flame exposure treatment, high-voltage shock exposure treatment, and ionizing radiation treatment; chemical treatments such as chromic acid treatment; and adhesion-enhancing treatments using a coating agent (primer), for the purpose of improving adhesion and retention of the thermosetting resin composition. The surface treatment for improving adhesion is preferably applied to the entire surface of the substrate on the side where the thermosetting resin composition is provided.

[0100] The thickness of the substrate is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of excellent support function and surface scratch resistance, and is preferably 300 μm or less, more preferably 200 μm or less, from the viewpoint of excellent transparency.

[0101] The substrate may have a surface protective film on its surface (the surface opposite to the thermosetting resin composition). When the optical film is used as the substrate, the optical film can be protected until use. However, the surface protective film is not necessarily provided.

[0102] The thermosetting resin composition may be prepared by forming the thermosetting resin composition on the release-treated surface of the release sheet. Furthermore, the substrate or a separate release sheet may be attached to the surface of the thermosetting resin composition. The thermosetting resin composition may also be formed on the substrate. Furthermore, the release sheet may be attached to the surface of the thermosetting resin composition. The thermosetting resin composition may be prepared by applying a resin composition that forms the thermosetting resin composition to the release-treated surface of a release sheet or the substrate to form a resin composition, and then removing the solvent or curing the resin composition by heating, or curing the resin composition by irradiating it with active energy rays, thereby solidifying the resin composition. When heating is performed, the formed thermosetting resin composition is kept in a state that allows it to be thermoset when encapsulating the optical semiconductor element. Examples of methods for applying the resin composition include roll coating, screen coating, and gravure coating.

[0103] An optical semiconductor device can be obtained by laminating the thermosetting resin composition or the optical semiconductor device encapsulation sheet onto a substrate on which an optical semiconductor element is disposed, thereby encapsulating the optical semiconductor element with the thermosetting resin composition. Specifically, first, if necessary, the release liner is peeled off to expose the thermosetting resin composition. Then, the exposed surface of the thermosetting resin composition is laminated to the substrate surface on which the optical semiconductor element is disposed, of an optical element comprising a substrate and optical semiconductor elements (preferably multiple optical semiconductor elements) disposed on the substrate. If the optical element comprises multiple optical semiconductor elements, the thermosetting resin composition is further arranged to fill the gaps between the multiple optical semiconductor elements, thereby embedding the multiple optical semiconductor elements collectively. The thermosetting resin composition is then heated and cured to encapsulate the optical semiconductor elements. In this way, the optical semiconductor element can be encapsulated using the thermosetting resin composition or the optical semiconductor device encapsulation sheet. Alternatively, the optical semiconductor element may be embedded by laminating the thermosetting resin composition or the optical semiconductor device encapsulation sheet under reduced pressure or under pressure. Examples of such methods include those disclosed in Japanese Patent Application Laid-Open No. 2016-29689 and Japanese Patent Application Laid-Open No. 6-97268.

[0104] [Optical semiconductor device] An optical semiconductor device can be produced using the thermosetting resin composition. The optical semiconductor device produced using the thermosetting resin composition includes a substrate, an optical semiconductor element disposed on the substrate, and a cured product of the thermosetting resin composition that encapsulates the optical semiconductor element. The cured product is a cured product of the thermosetting resin composition, specifically, includes a cured encapsulating layer that is thermally cured from the thermosetting resin composition.

[0105] Examples of the optical semiconductor element include light emitting diodes (LEDs) such as blue light emitting diodes, green light emitting diodes, red light emitting diodes, and ultraviolet light emitting diodes.

[0106] In the optical semiconductor device, the thermosetting resin composition has excellent conformability to irregularities when the optical semiconductor elements are convex portions and the gaps between the multiple optical semiconductor elements are concave portions, and is therefore excellent in embedding the optical semiconductor elements, and therefore it is preferable that the multiple optical semiconductor elements are encapsulated together.

[0107] FIG. 2 shows one embodiment of an optical semiconductor device using the optical semiconductor element encapsulation sheet 1 shown in FIG. 1. The optical semiconductor device 10 shown in FIG. 2 includes a substrate 5, a plurality of optical semiconductor elements 6 arranged on one surface of the substrate 5, and a cured product 1' of the optical semiconductor element encapsulation sheet that encapsulates the optical semiconductor elements 6. The cured product 1' of the optical semiconductor element encapsulation sheet is formed by peeling the release liner 4 from the optical semiconductor element encapsulation sheet 1 and thermally curing the thermosetting resin composition 3 to form a cured encapsulating layer 3'. The plurality of optical semiconductor elements 6 are encapsulated collectively in the cured encapsulating layer 3'. The cured encapsulating layer 3' conforms to the uneven shape formed by the plurality of optical semiconductor elements 6 and is in close contact with the optical semiconductor elements 6 and the substrate 5, embedding the optical semiconductor elements 6.

[0108] As described above, the optical semiconductor device encapsulates the optical semiconductor element with a cured encapsulating layer. The thermosetting resin composition has sufficient flexibility before thermal curing, providing excellent conformability, fully embedding the optical semiconductor element, and fixing the optical semiconductor element after thermal curing. Furthermore, warping of the substrate is unlikely to occur after thermal curing. Therefore, the optical semiconductor element is closely adhered to the cured encapsulating layer, providing excellent encapsulation of the optical semiconductor element. Furthermore, the thermosetting resin composition has excellent heat resistance after thermal curing. Therefore, even if the image display device generates heat or is heated during a reflow process after encapsulation, the shape of the cured encapsulating layer is unlikely to change after encapsulating the optical semiconductor element. Furthermore, because the side surfaces of the cured encapsulating layer have low adhesiveness, adjacent optical semiconductor devices can be easily separated from each other in a tiled state, and sheet damage and adhesion of adjacent optical semiconductor device sheets are unlikely to occur.

[0109] The optical semiconductor device may be a tiled structure of individual optical semiconductor devices, i.e., the optical semiconductor device may be a structure in which a plurality of optical semiconductor devices are arranged in a tiled pattern in a planar direction.

[0110] Figure 3 shows one embodiment of an optical semiconductor device fabricated by arranging multiple optical semiconductor devices. The optical semiconductor device 20 shown in Figure 3 has multiple optical semiconductor devices 10 arranged in a tiled pattern (tiling) in the planar direction, with four arranged vertically and four arranged horizontally, for a total of 16 devices. Although the optical semiconductor devices 10 are adjacent to each other at the boundary 20a between two adjacent optical semiconductor devices 10, they can be easily separated, and chipping of the side surface of the cured encapsulating layer 3' and adhesion of chipped resin from the side surface of the cured encapsulating layer 3' from one adjacent optical semiconductor device to the other are unlikely to occur.

[0111] The optical semiconductor device is preferably a backlight for a liquid crystal display, particularly a full-surface direct backlight. Furthermore, the backlight can be combined with a display panel to form an image display device. When the optical semiconductor device is a backlight for a liquid crystal display, the optical semiconductor element is an LED element. For example, in the backlight, a metal wiring layer is laminated on the substrate to send light-emission control signals to each LED element. The LED elements emitting red (R), green (G), and blue (B) light are alternately arranged on the display panel substrate via the metal wiring layer. The metal wiring layer is made of a metal such as copper, and reflects the light emitted by each LED element, reducing the visibility of the image. Furthermore, the light emitted by each LED element of each color (RGB) is mixed, reducing contrast.

[0112] Furthermore, the optical semiconductor device is preferably a self-luminous display device. Furthermore, an image display device can be formed by combining the self-luminous display device with a display panel, if necessary. When the optical semiconductor device is a self-luminous display device, the optical semiconductor element is an LED element. Examples of the self-luminous display device include an organic electroluminescence (organic EL) display device and the backlight. For example, in the self-luminous display device, a metal wiring layer is laminated on the substrate for sending a light emission control signal to each LED element. Each LED element emitting light of red (R), green (G), and blue (B) is alternately arranged on the substrate via the metal wiring layer. The metal wiring layer is made of a metal such as copper, and adjusts the light emission intensity of each LED element to display each color.

[0113] The thermosetting resin composition and the optical semiconductor element encapsulation sheet can be used in an optical semiconductor device that is folded when used, for example, an optical semiconductor device having a foldable image display device (flexible display) (particularly, a foldable image display device (foldable display)). Specifically, they can be used in a foldable backlight and a foldable self-luminous display device.

[0114] The thermosetting resin composition and the sheet for encapsulating an optical semiconductor element have excellent encapsulation properties for an optical semiconductor element, and therefore can be preferably used when the optical semiconductor device is a mini LED display device or a micro LED display device.

[0115] [Method of manufacturing optical semiconductor device] The optical semiconductor device can be produced by a production method including, for example, a step of bonding the optical semiconductor element encapsulation sheet to the optical semiconductor element provided on the substrate to encapsulate the optical semiconductor element with the thermosetting resin composition (embedding step), and a step of heating a laminate obtained through the embedding step, the laminate including the substrate, the optical semiconductor element disposed on the substrate, and the optical semiconductor element encapsulation sheet encapsulating the optical semiconductor element, to cure the thermosetting resin composition and obtain the cured product (heating step). The cured product is a cured product obtained by thermally curing the thermosetting resin composition, and specifically includes a cured encapsulating layer obtained by thermally curing the thermosetting resin composition.

[0116] The manufacturing method may further include a step of dicing the laminate that has undergone the heating step to obtain an optical semiconductor device (dicing step). The manufacturing method may also include a tiling step of arranging a plurality of optical semiconductor devices obtained in the dicing step so that they are in contact with each other in a planar direction. Hereinafter, the manufacturing methods for the optical semiconductor device 10 shown in FIG. 2 and the optical semiconductor device 20 shown in FIG. 3 will be described with reference to the manufacturing methods as appropriate.

[0117] (Embedding process) In the embedding step, the optical semiconductor element encapsulation sheet is attached to a substrate on which an optical semiconductor element is disposed, and the optical semiconductor element is encapsulated with a thermosetting resin composition. Specifically, in the embedding step, as shown in FIG. 4, the thermosetting resin composition 3 of the optical semiconductor element encapsulation sheet 1 from which the release liner 4 has been peeled is placed facing the surface of the substrate 5 on which the optical semiconductor element 6 is disposed, and the optical semiconductor element encapsulation sheet 1 is attached to the surface of the substrate 5 on which the optical semiconductor element 6 is disposed, and the optical semiconductor element 6 is embedded in the thermosetting resin composition 3 as shown in FIG. 4. For the purpose of trimming the edges to make the size uniform in the dicing step, as shown in FIG. 4, the substrate 5 used for attachment extends wider in the planar direction than the substrate 5 in the optical semiconductor device 10 shown in FIG. 2, and no optical semiconductor element 6 is disposed near the edge of the substrate 5. Furthermore, the optical semiconductor element encapsulation sheet 1 to be attached extends wider in the planar direction than the substrate 5 used for attachment. That is, the area of the surface of optical semiconductor element encapsulation sheet 1 facing substrate 5 to be bonded in the embedding step is larger than the area of the surface of substrate 5 facing optical semiconductor element encapsulation sheet 1 to be bonded in the embedding step.

[0118] The temperature during the lamination is, for example, within a range from room temperature to 150°C. Furthermore, reduced pressure or pressure may be applied during the lamination. By reducing pressure or applying pressure, it is possible to prevent voids from being formed between the thermosetting resin composition and the substrate or the optical semiconductor element. Furthermore, in the embedding step, it is preferable to apply pressure after laminating the optical semiconductor element encapsulation sheet under reduced pressure. When reduced pressure is applied, the pressure is, for example, 1 to 100 Pa, and the depressurization time is, for example, 5 to 600 seconds. When pressurized, the pressure is, for example, 0.05 to 0.5 MPa, and the depressurization time is, for example, 5 to 600 seconds.

[0119] (Heating process) In the heating step, a laminate (e.g., a laminate obtained in the embedding step) in which the optical semiconductor element encapsulation sheet is bonded to the substrate on which the optical semiconductor element is disposed is heated to cure the thermosetting resin composition. Specifically, in the heating step, as shown in Fig. 6, the thermosetting resin composition 3 is cured to form a cured encapsulating layer 3', thereby obtaining a cured product 1' of the optical semiconductor element encapsulation sheet 1. The heating temperature is, for example, within a range of 80 to 200°C, and the heating time is, for example, 1 minute to 24 hours.

[0120] (dicing process) In the dicing step, the laminate that has undergone the heating step is diced. Here, in the laminate to be subjected to the dicing step, the cured product 1' of the sheet for encapsulating optical semiconductor elements and the substrate 5 extend wider in the planar direction than the optical semiconductor device 10 that will ultimately be obtained, as described above. In the dicing step, the side edges of the cured product of the sheet for encapsulating optical semiconductor elements and the substrate are diced and removed. Specifically, dicing is performed at the positions indicated by the dashed lines in FIG. 7 to remove the side edges. The dicing can be performed by a known or conventional method, such as a method using a dicing blade or laser irradiation. In this manner, the optical semiconductor device 10 shown in FIG. 2 can be manufactured, for example.

[0121] (Tiling process) In the tiling step, the multiple optical semiconductor devices obtained in the dicing step are tiled so that they are in contact with each other in the planar direction. In this manner, for example, the optical semiconductor device 20 shown in FIG. 3 can be manufactured. The optical semiconductor device obtained by tiling has excellent sealing properties for optical semiconductor elements, and is less likely to suffer sheet damage or adhesion of the sheets of adjacent optical semiconductor devices when separating them from each other. [Example]

[0122] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0123] Example 1 A resin composition solution 1 with a solid content of 20% by mass was prepared by dissolving 100 parts by mass of an acrylic resin (glycidyl methacrylate (GMA):ethyl acrylate (EA):butyl methacrylate (BMA) = 40% by mass:28% by mass:32% by mass, weight average molecular weight 40,000) and 42 parts by mass (solid content equivalent) of silica filler (product name "MEK-ST-40", manufactured by Nissan Chemical Industries, Ltd.) in methyl ethyl ketone. The resin composition solution 1 was applied onto the release-treated surface of a release liner (a release-treated film made of a 50 μm-thick polyethylene terephthalate film treated with silicone release), and then dried at 130°C for 2 minutes to produce a sheet-shaped thermosetting resin composition 1 having a thickness (average thickness) of 20 μm.

[0124] Example 2 100 parts by mass of acrylic resin (GMA:EA:BMA = 7% by mass:48% by mass:45% by mass, weight average molecular weight 250,000) and 20 parts by mass (solid content equivalent) of silica filler (product name "MEK-ST-40", manufactured by Nissan Chemical Industries, Ltd.) were dissolved in methyl ethyl ketone to prepare resin composition solution 2 with a solid content concentration of 20% by mass. The resin composition solution 2 was applied onto the release-treated surface of a release liner (a release-treated film made of a 50 μm-thick polyethylene terephthalate film treated with silicone release), and then dried at 130°C for 2 minutes to produce a sheet-shaped thermosetting resin composition 2 having a thickness (average thickness) of 20 μm.

[0125] Example 3 100 parts by mass of acrylic resin (GMA:EA:BMA = 32% by mass:32% by mass:36% by mass, weight average molecular weight 40,000) and 55 parts by mass of acrylic resin (2-ethylhexyl acrylate (EHA):methyl methacrylate (MMA):methacrylic acid (MAA) = 22% by mass, 63% by mass:15% by mass, weight average molecular weight 10,000) were dissolved in methyl ethyl ketone to prepare resin composition solution 3 with a solids concentration of 20% by mass. The resin composition solution 3 was applied onto the release-treated surface of a release liner (a release-treated film made of a 50 μm-thick polyethylene terephthalate film treated with silicone release), and then dried at 130°C for 2 minutes to produce a sheet-shaped thermosetting resin composition 3 having a thickness (average thickness) of 20 μm.

[0126] Example 4 Resin composition solution 4 with a solids concentration of 20% by mass was prepared by dissolving 100 parts by mass of acrylic resin (GMA:EA:BMA = 32% by mass: 32% by mass: 36% by mass, weight average molecular weight 40,000), 70 parts by mass of acrylic resin (EHA:MMA:MAA = 22% by mass, 63% by mass: 15% by mass, weight average molecular weight 10,000), and 40 parts by mass of acrylic resin (GMA:butyl acrylate (BA) = 18% by mass: 82% by mass, weight average molecular weight 2,500) in methyl ethyl ketone. The resin composition solution 4 was applied onto the release-treated surface of a release liner (a release-treated film made of a 50 μm-thick polyethylene terephthalate film treated with silicone release), and then dried at 130°C for 2 minutes to produce a sheet-shaped thermosetting resin composition 4 having a thickness (average thickness) of 20 μm.

[0127] Comparative Example 1 Resin composition solution 5 having a solids concentration of 20% by mass was prepared by dissolving 100 parts by mass of acrylic resin (GMA:EA:BMA = 60% by mass:18% by mass:22% by mass, weight average molecular weight 450,000), 55 parts by mass of phenolic resin (trade name "MEHC-7500", manufactured by Meiwa Kasei Co., Ltd.), 53 parts by mass of epoxy resin (trade name "EPPN501HY", manufactured by Nippon Kayaku Co., Ltd.), and 120 parts by mass (solids content equivalent) of silica filler (trade name "MEK-ST-40", manufactured by Nissan Chemical Industries, Ltd.) in methyl ethyl ketone. The resin composition solution 5 was applied onto the release-treated surface of a release liner (a release-treated film made of a 50 μm-thick polyethylene terephthalate film treated with silicone release), and then dried at 130°C for 2 minutes to produce a sheet-shaped thermosetting resin composition 5 having a thickness (average thickness) of 20 μm.

[0128] Comparative Example 2 Resin composition solution 6 with a solids concentration of 20% by mass was prepared by dissolving 100 parts by mass of acrylic resin (GMA:EA:BMA = 3% by mass: 56% by mass: 31% by mass, weight average molecular weight 450,000), 44 parts by mass of phenolic resin (product name "MEHC-7500", manufactured by Meiwa Chemical Industry Co., Ltd.), and 59 parts by mass of epoxy resin (product name "JER828", manufactured by Mitsubishi Chemical Corporation) in methyl ethyl ketone. The resin composition solution 6 was applied onto the release-treated surface of a release liner (a release-treated film made of a 50 μm-thick polyethylene terephthalate film treated with silicone release), and then dried at 130°C for 2 minutes to produce a sheet-shaped thermosetting resin composition 6 having a thickness (average thickness) of 20 μm.

[0129] Comparative Example 3 Resin composition solution 7 with a solids concentration of 20% by mass was prepared by dissolving 100 parts by mass of acrylic resin (GMA:EA:BMA = 60% by mass:18% by mass:22% by mass, weight average molecular weight 450,000), 279 parts by mass of phenolic resin (trade name "MEHC-7500", manufactured by Meiwa Kasei Co., Ltd.), 287 parts by mass of epoxy resin (trade name "EPPN501HY", manufactured by Nippon Kayaku Co., Ltd.), and 470 parts by mass (solids content equivalent) of silica filler (trade name "SO-25R", manufactured by Admatechs Co., Ltd.) in methyl ethyl ketone. The resin composition solution 7 was applied onto the release-treated surface of a release liner (a release-treated film made of a 50 μm-thick polyethylene terephthalate film treated with silicone release), and then dried at 130°C for 2 minutes to produce a sheet-shaped thermosetting resin composition 7 having a thickness (average thickness) of 20 μm.

[0130] <Evaluation> The thermosetting resin compositions obtained in the examples and comparative examples were evaluated as follows, and the results are shown in the table below.

[0131] (1) 140°C shear loss modulus The thermosetting resin compositions obtained in the examples and comparative examples were laminated to prepare a laminate of thermosetting resin compositions with a thickness of approximately 300 μm, and then punched into a cylindrical shape with a diameter of 8 mm to prepare a measurement sample. The measurement sample was measured in shear mode using a rheometer (product name "HAAKE MARSIII Rheometer", manufactured by Thermo Scientific) at a frequency of 1 Hz in the range of 80 to 160°C at a heating rate of 5°C / min, and the shear loss modulus at 140°C was calculated.

[0132] (2) 25°C tensile storage modulus Measurement samples were cut out from the thermosetting resin compositions obtained in the examples and comparative examples into strips measuring 10 mm wide and 40 mm long using a cutter knife. The dynamic storage modulus of each sample was measured using a solid viscoelasticity measuring device (trade name "RSAIII" manufactured by Rheometric Scientific) in tension mode under conditions of a frequency of 1 Hz, a chuck distance of 22.5 mm, and a temperature rise rate of 5°C / min in the range of -30 to 250°C, and the tensile storage modulus at 25°C was calculated.

[0133] (3) Tensile storage modulus at 150°C after curing The thermosetting resin compositions obtained in the examples and comparative examples were stacked at 60°C to a thickness of 200 μm, cut into strips measuring 40 mm in length and 10 mm in width with a utility knife, and then heated to 150°C for 1 hour to cure, resulting in measurement samples. The dynamic storage modulus of the measurement samples was measured using a solid viscoelasticity measuring device (trade name "RSAIII", manufactured by Rheometric Scientific) in tension mode under conditions of a chuck distance of 22.5 mm, a frequency of 1 Hz, and a heating rate of 5°C / min in the range of -30 to 250°C, and the tensile storage modulus at 150°C was calculated.

[0134] (4) Glass transition temperature and tan δ after curing The thermosetting resin compositions obtained in the examples and comparative examples were stacked at 60°C until a thickness of 300 μm was reached, and then strips measuring 30 mm long and 10 mm wide were cut out. Next, using a dynamic viscoelasticity measuring device (trade name "RSAIII" manufactured by Rheometric Scientific) the storage modulus and loss modulus were measured at a heating rate of 5°C / min in the range of -30 to 250°C, with a chuck distance of 22.5 mm and a frequency of 1 Hz. The glass transition temperature was calculated from the peak value of tan δ. This peak value was also taken as the tan δ of the glass transition temperature.

[0135] (5) Light transmittance (before curing) The thermosetting resin compositions obtained in the examples and comparative examples were similarly prepared to have a thickness of 50 μm and used as measurement samples. Then, using an ultraviolet-visible-near-infrared spectrophotometer (product name "V-670DS", manufactured by JASCO Corporation) and an integrating sphere unit, the total light transmittance spectrum in the wavelength range of 300 to 2000 nm was measured, and the transmittance at a wavelength of 400 nm was read from the obtained spectrum.

[0136] (6) Light transmittance (after curing) A 50 μm thick sample was prepared from the thermosetting resin compositions obtained in the Examples and Comparative Examples in the same manner, then heated at 150° C. for 1 hour to cure, and then stored at 125° C. for 1000 hours to prepare a measurement sample. A UV-Vis-NIR spectrophotometer (product name "V-670DS", manufactured by JASCO Corporation) and an integrating sphere unit were used to measure the total light transmittance spectrum in the wavelength range of 300 to 2000 nm, and the transmittance at a wavelength of 400 nm was read from the obtained spectrum.

[0137] (7) Haze value A measurement sample was prepared by similarly preparing a 50 μm thick sample from each of the thermosetting resin compositions obtained in the examples and comparative examples, curing the sample by heating at 150° C. for 1 hour, and then storing the sample at 125° C. for 1,000 hours. The sample was then set in the sample chamber of a turbidity meter (product name "NDHG2000", manufactured by Nippon Denshoku Industries Co., Ltd.), and the haze value was measured using a D65 light source.

[0138] (8) Shore D hardness The thermosetting resin compositions obtained in the examples and comparative examples were laminated to prepare a 3 mm thick thermosetting resin composition laminate, which was then heat-cured by heating at 150°C for 1 hour and then at 175°C for 1 hour to prepare a measurement sample. The Shore D hardness was then measured using a durometer type D indenter.

[0139] (9) Amount of warpage The thermosetting resin compositions obtained in the examples and comparative examples were attached to a wafer having a thickness of 100 μm and cured by heating at 150° C. for 1 hour to prepare a measurement sample. The warpage of the wafer before thermal curing was set to 0 mm, and the amount of warpage of the wafer when the thermosetting resin composition was thermally cured was measured.

[0140] (10) Embeddability The thermosetting resin compositions obtained in the examples and comparative examples were bonded to a 10 mm x 10 mm x 200 μm mirror chip at a temperature of 80°C, a pressure of 0.3 MPa, and a bonding speed of 10 mm / sec. They were then bonded to a BGA substrate with a surface roughness of 10 μm using a die bonder (product name "Die Bonder SPA-300" manufactured by Shinkawa Co., Ltd.) at a stage temperature of 140°C, a die bond load of 0.2 MPa, and a die bond time of 2 seconds. Voids between the thermosetting resin composition and the substrate were observed using an ultrasonic imaging device (product name "FineSAT III" manufactured by Hitachi Power Solutions Co., Ltd.). The area occupied by the voids in the observed images was calculated using binarization software "WinRoof ver. 5.6." The distance of the thermosetting resin composition protruding from the chip was measured using an optical microscope. The embeddability was evaluated according to the following criteria. ○: The area occupied by voids is less than 10% of the surface area of the thermosetting resin composition, and the maximum protrusion amount is less than 100 μm. ×: The area occupied by voids is 10% or more of the surface area of the thermosetting resin composition, or the maximum protrusion amount is 100 μm or more

[0141] (11) Dicing evaluation The thermosetting resin compositions obtained in the examples and comparative examples were laminated to the patterned surface of a substrate (trade name "Lead-free Universal Board ICB93SGPBF", manufactured by Sanhayato Co., Ltd.) using a hand roller, with the release liner removed to expose the entire surface of the thermosetting resin composition. Test samples were prepared. The laminated area of the thermosetting resin composition was larger than the area of the substrate to be laminated. The lamination was performed in an environment of 22°C and 50% humidity, taking care to avoid the introduction of air bubbles. The thermosetting resin composition was then cured by heating at 150°C for 1 hour.

[0142] After thermal curing, dicing tape (product name "NBD-5172K", manufactured by Nitto Denko Corporation) was attached to the surface of the substrate, the side of the test sample to which the thermosetting resin composition was not attached. A dicing ring for dicing was attached to the adhesive surface of the dicing tape. After attachment, the dicing ring was left for 30 minutes in a light-shielded environment at a temperature of 22°C. Then, the laminate of the test sample and dicing tape was subjected to blade dicing at a position 5 mm inward from the side edge of the substrate under the dicing conditions described below. <Dicing conditions> Dicing machine: Product name "DFD-6450", manufactured by Disco Corporation Cutting method: Single cut Dicing speed: 30mm / sec Dicing blade: Product name "P1A861 SDC400N75BR597", manufactured by Disco Corporation Dicing blade rotation speed: 30,000 rpm Blade height: 85 μm Water amount: 1.5L / min Dicing interval: 10mm Dicing distance per dicing: the entire length of the test sample

[0143] The blade used for dicing was one that had been dress diced using the following method. A dicing ring and a board (product name "DRESSER BOARD BGCA0172", manufactured by Disco Corporation) were attached to the adhesive layer of a dicing tape (product name "NBD-7163K", manufactured by Nitto Denko Corporation) to prepare a workpiece for processing. The resulting workpiece was then diced under the following dress dicing conditions to obtain the blade for the blade dicing. <Dress dicing conditions> Dicing machine: Product name "DFD-6450", manufactured by Disco Corporation Cutting method: Single cut Dicing speed: 55mm / sec Dicing blade: Product name "P1A861 SDC400N75BR597" (new), manufactured by Disco Corporation Dicing blade rotation speed: 35,000 rpm Blade height: 500 μm Water amount: 1.5L / min Dicing distance per dicing: total length of board Dicing interval: 1mm increments Dicing times: 100 times

[0144] Thereafter, the diced surface of the laminate of the test sample and the substrate cut into strips by blade dicing was checked to see if there was any stickiness. If stickiness was confirmed, it was evaluated as "X", and if not, it was evaluated as "O".

[0145] [Table 1]

[0146] As shown in Table 1, the thermosetting resin compositions of the present invention (Examples) were evaluated as having a small amount of wafer warpage and excellent sealing properties. They were also evaluated as having excellent heat resistance and good dicing properties. On the other hand, when the thermosetting resin composition had a small 150°C tensile storage modulus E' after curing or a small 25°C tensile storage modulus E' before curing (Comparative Example 2), the dicing properties were evaluated as poor. It was assumed that the stickiness of adjacent side surfaces during tiling would increase the adhesion between the side surfaces of the optical semiconductor device. Furthermore, when the thermosetting resin composition had a large 150°C tensile storage modulus E' after curing or a large 25°C tensile storage modulus E' before curing (Comparative Examples 1 and 3), the amount of wafer warpage was large, and the sealing properties for the optical semiconductor device were evaluated as poor. [Explanation of symbols]

[0147] 1. Optical semiconductor element encapsulation sheet 1' Cured sheet for encapsulating optical semiconductor elements 2 Base material part 21 Optical Film 22 adhesive layer 23 Plastic Film 3 Thermosetting resin composition 3' Cured sealing layer 4 Release Liner 5. Substrate 6. Optical semiconductor elements 10,20 Optical semiconductor device

Claims

1. A sheet-shaped thermosetting resin composition for encapsulating one or more optical semiconductor elements disposed on a substrate, comprising: the thermosetting resin composition has a tensile storage modulus E' at 150°C after curing of 0.1 to 10 MPa; the thermosetting resin composition contains an acrylic resin as an organic component, A thermosetting resin composition that satisfies the following (i) and / or (ii): (i) The acrylic resin includes an acrylic resin having a first functional group that is a thermosetting functional group, and an acrylic resin having a second functional group that is a thermosetting functional group that can react with the first functional group by heat, and the combination of the first functional group and the second functional group is one or more selected from a carboxy group and an epoxy group, an epoxy group and a carboxy group, a carboxy group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, and an isocyanate group and a hydroxy group. (ii) The acrylic resin contains a glycidyl group-containing acrylic resin, and the thermosetting resin composition further contains inorganic particles having a silanol group.

2. 2. The thermosetting resin composition according to claim 1, which has a glass transition temperature of 20 to 100°C after curing.

3. 3. The thermosetting resin composition according to claim 1, wherein the tan δ at the glass transition temperature after curing is 0.7 to 1.

5.

4. A sheet-shaped thermosetting resin composition for encapsulating one or more optical semiconductor elements disposed on a substrate, comprising: The thermosetting resin composition has a tensile storage modulus E' at 25°C of 10 to 1500 MPa, the thermosetting resin composition contains an acrylic resin as an organic component, A thermosetting resin composition that satisfies the following (i) and / or (ii): (i) The acrylic resin includes an acrylic resin having a first functional group that is a thermosetting functional group, and an acrylic resin having a second functional group that is a thermosetting functional group that can react with the first functional group by heat, and the combination of the first functional group and the second functional group is one or more selected from a carboxy group and an epoxy group, an epoxy group and a carboxy group, a carboxy group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, and an isocyanate group and a hydroxy group. (ii) The acrylic resin contains a glycidyl group-containing acrylic resin, and the thermosetting resin composition further contains inorganic particles having a silanol group.

5. 5. The thermosetting resin composition according to claim 4, wherein the 140° C. shear loss modulus G″ is 1 to 20 KPa.

6. The thermosetting resin composition according to any one of claims 1 to 5, further comprising inorganic particles.

7. 7. The thermosetting resin composition according to claim 1, which has a haze value of 1.0% or less after heat curing.

8. 8. The thermosetting resin composition according to claim 1, wherein the ratio of the light transmittance after curing to the light transmittance before curing [after curing / before curing] is 0.95 or more.

9. An optical semiconductor device comprising: a substrate; an optical semiconductor element disposed on the substrate; and a cured product obtained by curing the thermosetting resin composition according to any one of claims 1 to 8, which encapsulates the optical semiconductor element.

10. 10. The optical semiconductor device according to claim 9, which is a backlight for a liquid crystal display.

11. An image display device comprising the backlight according to claim 10 and a display panel.

12. 10. The optical semiconductor device according to claim 9, which is a self-luminous display device.

13. An image display device comprising the self-luminous display device according to claim 12.

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