Thermosetting resin composition

Abstract

To provide a resin composition in sheet form for encapsulating optical semiconductor elements, which has excellent light transmittance and heat resistance when encapsulating optical semiconductor elements.SOLUTION: A thermosetting resin composition 3 is a sheet-shaped thermosetting resin composition for encapsulating one or more optical semiconductor elements 6 placed on a substrate 5, the thermosetting resin composition 3 contains acrylic resin as an organic component, and the percentage of the acrylic resin in the organic component is 85 mass% or more. It is preferred that the acrylic resin contains glycidyl group-containing acrylic resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a thermosetting resin composition. More specifically, it relates to a sheet-like thermosetting resin composition for encapsulating one or more optical semiconductor elements disposed on a substrate.

Background Art

[0002] For example, a backlight used in a liquid crystal display device has a structure in which a plurality of LEDs are disposed on a substrate, and the plurality of LEDs are encapsulated with an encapsulating resin. As a method of encapsulating the plurality of LEDs collectively using the encapsulating resin, a method is known in which a liquid resin is poured into a region where the plurality of LEDs are disposed, the plurality of LEDs are buried, and then the liquid resin is cured by heat or ultraviolet irradiation.

[0003] However, in the method of encapsulating an optical semiconductor element such as an LED using a liquid resin, there is a problem of poor handleability, such as dripping when applying the liquid resin and adhesion of the liquid resin to unintended regions. On the other hand, instead of using a liquid resin, by adopting the form of an encapsulating sheet provided with an encapsulating layer for encapsulating the optical semiconductor element, it is conceivable to encapsulate the optical semiconductor element easily, in a simple process, and in a short time. As such an encapsulating sheet, an encapsulating material 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

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the sealing sheet using a thermoplastic resin may soften and melt the thermoplastic resin near the melting point, and tends to be inferior in heat resistance. For this reason, after sealing an optical semiconductor element using a sealing sheet made of a thermoplastic resin, for example, when the image display device to which the sealing sheet is applied generates heat or when it is heated during a reflow process after sealing, there is a problem such that the shape of the sealing sheet changes. In addition, the above sealing sheet is required to have excellent light transmittance of the light emitted from the optical semiconductor element.

[0006] The present invention has been conceived under such circumstances, and an object thereof is to provide a sheet-like resin composition for sealing an optical semiconductor element, which is excellent in light transmittance and heat resistance when sealing the optical semiconductor element.

Means for Solving the Problems

[0007] As a result of intensive studies to achieve the above object, the present inventor has found that a sheet-like resin composition for sealing an optical semiconductor element, which is a thermosetting resin composition in which the content ratio of an acrylic resin is a specific value or more, is excellent in light transmittance and heat resistance when sealing the optical semiconductor element. The present invention has been completed based on these findings.

[0008] That is, the present invention is a sheet-like thermosetting resin composition for sealing one or more optical semiconductor elements disposed on a substrate, The thermosetting resin composition contains an acrylic resin as an organic component, A thermosetting resin composition is provided in which the content ratio of the acrylic resin in the organic component is 85% by mass or more.

[0009] Since the above thermosetting resin composition has thermosetting properties, a sheet-like thermosetting resin composition can be bonded to a substrate provided with an optical semiconductor element to embed the optical semiconductor element in the thermosetting resin composition, and then cured by heating to seal the optical semiconductor element. Further, since the thermosetting resin composition is difficult to soften and melt by heating after thermosetting, it has excellent heat resistance. Furthermore, as described above, the above thermosetting resin composition contains 85% by mass or more of an acrylic resin as an organic component. Thereby, the above thermosetting resin composition has excellent light transmittance after thermosetting.

[0010] It is preferable that the above acrylic resin includes a glycidyl group-containing acrylic resin. Thereby, the glycidyl group acts as a thermosetting functional group, and even when no curing agent is blended, the reaction of the glycidyl group proceeds by thermosetting, and the above thermosetting resin composition cures. For this reason, the above thermosetting resin composition has appropriate flexibility after thermosetting and is excellent in the sealing property of the optical semiconductor element.

[0011] It is preferable that the above glycidyl group-containing acrylic resin includes a structural unit derived from a glycidyl group-containing (meth)acrylate ester. Further, the content ratio of the structural unit derived from the glycidyl group-containing (meth)acrylate ester in the above glycidyl group-containing acrylic resin is preferably 5 to 50% by mass. When the above content ratio is within the above range, the above thermosetting resin composition has appropriate flexibility after thermosetting and is excellent in the sealing property of the optical semiconductor element.

[0012] The weight average molecular weight of the above glycidyl group-containing acrylic resin is preferably 2000 to 400000. When the above weight average molecular weight is within the above range, the embedding property of the optical semiconductor element is more excellent. Further, the content ratio of the glycidyl group-containing acrylic resin in the above organic component is preferably 40% by mass or more. When the above content ratio is 40% by mass or more, the embedding property of the optical semiconductor element is more excellent.

[0013] The haze value after thermosetting of the above thermosetting resin composition is preferably 0.1 to 1.0%. When the haze value is within the above range, it has excellent light transmittance after thermosetting and is preferable for image display device applications.

[0014] The Shore D hardness after thermosetting of the above thermosetting resin composition is preferably 50 to 100. When the Shore D hardness is within the above range, the surface has excellent scratch resistance.

[0015] When the above thermosetting resin composition is thermoset in a state of being bonded to a wafer with a thickness of 100 μm, the warpage amount of the wafer after thermosetting with respect to before thermosetting is preferably 4 mm or less. When the warpage amount is 4 mm or less, the sealing property of the optical semiconductor element is more excellent after thermosetting.

[0016] The light transmittance of the above thermosetting resin composition at a wavelength of 400 nm is preferably 85% or more. When the light transmittance is 85% or more, it has excellent light transmittance and is preferable for image display device applications.

[0017] The ratio [after curing / before curing] of the light transmittance after curing to the light transmittance before curing of the above thermosetting resin composition is preferably 0.95 or more. When the ratio is 0.95 or more, coloring such as whitening and yellowing hardly occurs before and after thermosetting, it has excellent light transmittance, and is preferable for image display device applications.

[0018] Further, the present invention provides an optical semiconductor device including a substrate, an optical semiconductor element disposed on the substrate, and a cured product obtained by curing the above thermosetting resin composition for sealing the optical semiconductor element. Such an optical semiconductor device has excellent sealing property of the optical semiconductor element by the cured product and excellent heat resistance.

[0019] The above optical semiconductor device may be a backlight of a liquid crystal screen. Further, the above optical semiconductor device may be a self-emitting display device.

[0020] Further, the present invention provides an image display device including the above backlight and a display panel.

[0021] Furthermore, the present invention provides an image display device including the above-described self-luminous display device.

Advantages of the Invention

[0022] According to the thermosetting resin composition of the present invention, it has excellent sealing properties for optical semiconductor elements and excellent heat resistance. Therefore, even when the image display device to which the sheet-like thermosetting resin composition is applied generates heat or is heated when subjected to a reflow process after sealing, the shape is less likely to change. In addition, the sealed sheet can be subjected to a heating process such as a reflow process, improving the degree of freedom in the process when manufacturing an optical semiconductor device.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0024] [Thermosetting Resin Composition] The thermosetting resin composition of the present invention is a sheet-like thermosetting resin composition for encapsulating one or more optical semiconductor elements disposed on a substrate. In this specification, "encapsulating an optical semiconductor element" means embedding at least a part of the optical semiconductor element in the thermosetting resin composition. Since the above thermosetting resin composition has thermosetting properties, after a sheet-like thermosetting resin composition is bonded to a substrate provided with an optical semiconductor element and the optical semiconductor element is embedded in the thermosetting resin composition, it can be cured by heating to encapsulate the optical semiconductor element. Further, since the thermosetting resin composition is hardly softened and melted by heating after thermosetting, it has excellent heat resistance.

[0025] The above thermosetting resin composition contains at least an acrylic resin as an organic component. The content ratio of the acrylic resin in the above organic component is 85% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, based on the total amount (100% by mass) of the organic components in the above thermosetting resin composition. When the above content ratio is 85% by mass or more, the above thermosetting resin composition has excellent light transmittance after thermosetting. Note that the above content ratio may be 100% by mass.

[0026] The above 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) as a structural unit of the resin (polymer). Only one kind of the above acrylic resin may be used, or two or more kinds may be used.

[0027] The above acrylic resin is preferably a resin containing the largest mass ratio of a structural unit derived from a (meth)acrylate ester. In this specification, "(meth)acryl" represents "acryl" and / or "methacryl" (either one or both of "acryl" and "methacryl"), and the same applies to others.

[0028] The above acrylic resin preferably has a thermosetting functional group. Examples of the thermosetting functional group include epoxy group-containing groups such as glycidyl groups, carboxy groups, hydroxy groups, isocyanate groups, aziridyl groups, and the like. Among them, epoxy group-containing groups are preferred, and glycidyl groups are more preferred. That is, as the thermosetting functional group-containing acrylic resin, glycidyl group-containing acrylic resins are particularly preferred. The above thermosetting functional group may be used alone or in combination of two or more.

[0029] The acrylic resin having the above 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 (thermosetting functional group-containing acrylic monomer). Examples of the monomer having the thermosetting functional group include epoxy group-containing (meth)acrylic acid esters such as glycidyl group-containing (meth)acrylic acid esters, carboxy group-containing monomers, acid anhydride group-containing monomers, and hydroxy group-containing (meth)acrylic acid esters.

[0030] Examples of the glycidyl group-containing (meth)acrylic acid ester include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and the like.

[0031] 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, and the like. Examples of the acid anhydride group-containing monomer include maleic anhydride, itaconic anhydride, and the like.

[0032] 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, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, and the like.

[0033] Among the thermosetting functional group-containing acrylic monomers, epoxy group-containing (meth)acrylic acid esters are preferred, and glycidyl group-containing (meth)acrylic acid esters are more preferred. When the acrylic resin contains a structural unit derived from a glycidyl group-containing (meth)acrylic acid ester, the glycidyl group acts as a thermosetting functional group, and even when no curing agent is blended, the reaction of the glycidyl group proceeds by thermosetting, and the thermosetting resin composition cures. Therefore, the thermosetting resin composition has appropriate flexibility after thermosetting and is excellent in the sealing property of the optical semiconductor element.

[0034] The content ratio of the structural unit derived from the glycidyl group-containing (meth)acrylic acid ester is preferably 5 to 50% by mass, more preferably 6 to 45% by mass, based on the total amount (100% by mass) of all the structural units of the glycidyl group-containing acrylic resin. When the content ratio is within the above range, the thermosetting resin composition has appropriate flexibility after thermosetting and is excellent in the sealing property of the optical semiconductor element.

[0035] The thermosetting functional group-containing acrylic resin may contain a structural unit derived from other monomers other than the thermosetting functional group-containing monomer. Examples of the other monomers include other (meth)acrylic acid esters other than the thermosetting functional group-containing acrylic monomers. Only one kind of the other monomers may be used, or two or more kinds may be used.

[0036] Examples of the above-mentioned 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 alone or in combination of two or more.

[0037] Examples of the above-mentioned (meth)acrylic acid alkyl esters 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, 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, eicosyl (meth)acrylate, etc.

[0038] Among the above alkyl (meth)acrylates, those having a linear or branched aliphatic hydrocarbon group with 1 to 20 carbon atoms (preferably 1 to 14, more preferably 2 to 10, and still more preferably 2 to 8) are preferred. When the number of carbon atoms is within the above range, the flexibility of the above thermosetting group-containing acrylic resin during thermosetting is more likely to be appropriate, and the embedding property is further improved.

[0039] Examples of the (meth)acrylate having an alicyclic hydrocarbon group include (meth)acrylates having a monocyclic aliphatic hydrocarbon ring such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, cyclooctyl (meth)acrylate; (meth)acrylates having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; (meth)acrylates having an aliphatic hydrocarbon ring of three or more rings such as dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, and the like.

[0040] Examples of the (meth)acrylate having an aromatic hydrocarbon group include phenyl (meth)acrylate, benzyl (meth)acrylate, and the like.

[0041] Examples of the hydrocarbon group-containing (meth)acrylate having an alkoxy group include those in which one or more hydrogen atoms in the hydrocarbon group of the above hydrocarbon group-containing (meth)acrylate are substituted with an alkoxy group, such as 2-methoxymethyl ester, 2-methoxyethyl ester, 2-methoxybutyl ester of (meth)acrylic acid, and the like.

[0042] In order to appropriately exhibit basic properties such as adhesiveness and adhesion to an optical semiconductor element by the hydrocarbon group-containing (meth)acrylate ester which may have the above alkoxy group in the thermosetting resin composition, the ratio of the hydrocarbon group-containing (meth)acrylate ester which may have the above alkoxy group to all the constituent units of the above thermosetting functional group-containing acrylic resin is preferably 50 to 95% by mass, more preferably 55 to 94% by mass, based on the total amount (100% by mass) of all the constituent units of the above thermosetting functional group-containing acrylic resin.

[0043] Examples of the other monomer components further 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 styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropane sulfonic acid, (meth)acrylamidopropane sulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalene sulfonic acid, and the like. Examples of the phosphoric acid group-containing monomers include 2-hydroxyethylacryloyl phosphate and the like. Examples of the nitrogen atom-containing monomers include morpholino group-containing monomers such as (meth)acryloylmorpholine, cyano group-containing monomers such as (meth)acrylonitrile, amide group-containing monomers such as (meth)acrylamide, and the like.

[0044] In order to form a crosslinked structure in the polymer skeleton of the above-mentioned acrylic resin containing a thermosetting functional group, it may contain a structural unit derived from a polyfunctional (meth)acrylate copolymerizable with the monomer components constituting the acrylic resin. Examples of the above 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, dipentaerythritol hexa(meth)acrylate, and the like. Only one kind of the above polyfunctional (meth)acrylate may be used, or two or more kinds may be used.

[0045] The above-mentioned acrylic resin containing a thermosetting functional group is obtained by polymerizing the above various monomer components. The polymerization method is not particularly limited, and examples thereof include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by irradiation with active energy rays (active energy ray polymerization method). Further, the obtained acrylic resin may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

[0046] The weight average molecular weight of the above glycidyl group-containing acrylic resin is preferably 2000 to 400000. When the weight average molecular weight is within the above range, the embedding property of the optical semiconductor element is excellent. The weight average molecular weight refers to a value measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

[0047] As the glycidyl group-containing acrylic resin, from the viewpoint of having a certain degree of hardness after curing of the thermosetting resin composition and reducing the adhesion between the side surfaces of the optical semiconductor device whose side surfaces are cut, among others, those having a weight average molecular weight of 30,000 to 300,000 are preferably included. Further, as the glycidyl group-containing acrylic resin, from the viewpoint of reducing the loss elastic modulus before curing and further improving the embedding property, those having a weight average molecular weight of 2,000 to 20,000 (preferably 2,000 to 10,000) may also be included.

[0048] The content ratio 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 still more preferably 60% by mass or more, based on the total amount (100% by mass) of the organic components in the thermosetting resin composition. When the content ratio is 40% by mass or more, the embedding property of the optical semiconductor element is more excellent.

[0049] The thermosetting resin composition preferably contains a component having a functional group (second functional group) capable of reacting with heat with the thermosetting functional group (first functional group) in the above-mentioned thermosetting functional group-containing acrylic resin. The second functional group is also a thermosetting functional group. In this case, when the thermosetting resin composition is heated, the reaction between the first functional group and the second functional group promotes the curing of the thermosetting resin composition more.

[0050] The component having the second functional group may be a glycidyl group-containing acrylic resin other than the thermosetting functional group-containing acrylic resin having the first functional group, or may be another component having the second functional group. Only one kind of the component having the second functional group may be used, or two or more kinds may be used.

[0051] Examples of the combination 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, and the like. The above combination may be only one kind or two or more kinds.

[0052] When the glycidyl group-containing acrylic resin is included, the thermosetting resin composition preferably includes, as a component having the second functional group, 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, a hydroxy group, etc. Among them, a carboxy group and a hydroxy group are preferable. From the viewpoint of high acidity and excellent reactivity with an epoxy group, a silanol group is preferable as the hydroxy group.

[0053] The component having the carboxy group is preferably the above organic component, more preferably a carboxy group-containing acrylic resin. When the carboxy group-containing acrylic resin is contained, the reaction between the glycidyl group and the carboxy group in the glycidyl group-containing acrylic resin proceeds more easily even when no curing agent is blended, and the sealing property of the optical semiconductor element is more excellent. In addition, the surface scratch resistance is even more excellent.

[0054] The carboxy group-containing acrylic resin preferably contains a structural unit derived from a carboxy group-containing monomer, more preferably a structural unit derived from a carboxy group-containing acrylic monomer. 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, and the like.

[0055] The content ratio of the structural unit derived from the carboxy group-containing acrylic monomer is preferably 1 to 50% by mass, more preferably 10 to 40% by mass, based on the total amount (100% by mass) of all the structural units of the carboxy group-containing acrylic resin. When the content ratio is within the above range, the thermosetting resin composition has appropriate flexibility after thermosetting and is excellent in the sealing property of the optical semiconductor element.

[0056] The carboxy group-containing acrylic resin may contain a structural unit derived from other monomers other than the carboxy group-containing monomer. Examples of the other monomers include other (meth)acrylic acid esters other than the thermosetting functional group-containing acrylic monomer, the polar group-containing monomer, the polyfunctional monomer, and the like. Only one kind of the other monomers may be used, or two or more kinds may be used.

[0057] Examples of the other (meth)acrylic acid ester include a hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group. Among the (meth)acrylic acid alkyl esters in the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group, a (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 1 to 10, still more preferably 1 to 8) is preferable. When the number of carbon atoms is within the above range, it is easier to make the flexibility of the thermosetting group-containing acrylic resin more appropriate and the embedding property is further improved.

[0058] In order to appropriately exhibit the basic properties such as adhesiveness and adhesion to an optical semiconductor element by the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group in the thermosetting resin composition, the ratio of the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group to the total amount (100% by mass) of all the structural units of the carboxy group-containing acrylic resin is preferably 50 to 95% by mass, more preferably 60 to 90% by mass.

[0059] The weight average molecular weight of the carboxyl group-containing acrylic resin is preferably from 1,000 to 200,000, more preferably from 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 more excellent. The weight average molecular weight refers to a value measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene conversion.

[0060] When the carboxyl group-containing acrylic resin is included, the content ratio of the carboxyl group-containing acrylic resin in the organic component is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, still more preferably 25 to 45% by mass, based on the total amount (100% by mass) of the organic components in the thermosetting resin composition. When the content ratio is within the above range, the thermosetting property of the thermosetting resin composition is more excellent. Also, the surface scratch resistance is more excellent.

[0061] The content ratio of the organic component in the thermosetting resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more, based on the total amount (100% by mass) of the thermosetting resin composition. When the content ratio is 50% by mass or more, the flexibility of the thermosetting resin composition is excellent and the embedding property of the optical semiconductor element is more excellent. The content ratio may be 100% by mass.

[0062] The thermosetting resin composition may contain inorganic particles. When the inorganic particles are included, warpage is less likely to occur after curing of the thermosetting resin composition. Also, the dicing property is excellent and high heat resistance reliability is ensured. The inorganic particles may have various shapes such as spherical, needle-like, and flake-like. Only one kind of the inorganic particles may be used, or two or more kinds may be used.

[0063] The above inorganic particles are preferably inorganic particles having a silanol group, more preferably silica particles. When the inorganic particles having a silanol group (especially silica particles) are contained, the inorganic particles correspond to the other components having the second functional group, and the silanol group acts as a thermosetting functional group. Even when no curing agent is blended, the reaction between the glycidyl group and the silanol group in the glycidyl group-containing acrylic resin proceeds more easily, and the thermosetting resin composition has a certain degree of hardness before thermosetting, so that the sealing property of the optical semiconductor element is excellent. Further, warping of the thermosetting resin composition cured after sealing is suppressed, and the sealing property is further improved.

[0064] The average particle size of the above inorganic particles is preferably 50 nm or less (for example, 1 to 50 nm), more preferably 30 nm or less (for example, 3 to 30 nm). When the average particle size is 50 μm or less, the total surface area of the inorganic particles becomes sufficiently large. Therefore, when the inorganic particles have a silanol group, the amount of the silanol group increases, and the reactivity with the epoxy group becomes higher. In addition, the thermosetting resin composition has excellent light transmittance after curing, and high heat resistance reliability is ensured. The average particle size of the filler can be determined using, for example, a photometric particle size distribution meter (for example, trade name "LA-910", manufactured by Horiba, Ltd.).

[0065] When the above thermosetting resin composition contains the above inorganic particles, the content of the inorganic particles is preferably 1 to 50 parts by mass, more preferably 5 to 45 parts by mass, based on 100 parts by mass of the total amount of the organic components. When the content is 1 part by mass or more, the thermosetting property of the thermosetting resin composition is more excellent. When the content is 50 parts by mass or less, the thermosetting resin composition has excellent flexibility, excellent embedability of the optical semiconductor element, and excellent surface scratch resistance.

[0066] The above thermosetting resin composition may contain other components other than the various components described above, as long as the effects of the present invention are not impaired. Examples of the other components include resins other than acrylic resins, crosslinking accelerators, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, anti-aging agents, other fillers (organic fillers, etc.), colorants (pigments, dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, granular materials, foil materials, and the like. Each of the above other components may be used alone or in combination of two or more kinds.

[0067] As the above colorant, a black colorant is preferable. As the above black colorant, known or commonly used colorants (pigments, dyes, etc.) for exhibiting black can be used. For example, 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 complex, anthraquinone-based colorant, zirconium nitride, and the like can be mentioned. The black colorant may be used alone or in combination of two or more kinds. Further, a colorant that functions as a black colorant by combining colorants that exhibit colors other than black may be used.

[0068] The content ratio of the curing agent that promotes the reaction of the thermosetting functional groups or forms crosslinks in the above thermosetting resin composition is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, still more preferably 0.1% by mass or less, still more preferably 0.01% by mass or less, and particularly preferably it contains substantially none. Even when no curing agent is blended in the above glycidyl group-containing acrylic resin, the reaction of the glycidyl groups proceeds by thermosetting, and the above thermosetting resin composition cures. Therefore, when the above content ratio is 10% by mass or less, the above thermosetting resin composition has appropriate flexibility after thermosetting and is excellent in the sealing property of the optical semiconductor element. Also, it is excellent in light transmittance.

[0069] Examples of the above curing agent include those having an effect of promoting the thermosetting of glycidyl groups. Specifically, epoxy resins, phenol resins, amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, thermosetting polyimide resins, etc. can be mentioned.

[0070] The haze value of the above thermosetting resin composition is preferably 1.0% or less, more preferably 0.8% or less. The above haze value may be 0.1% or more. When the above haze value is within the above range, it is excellent in light transmittance after thermosetting and is preferable for use in image display devices. Also, the above thermosetting resin composition can, for example, not contain a curing agent or minimize its blending ratio, and can be produced with a simple configuration, so it is possible to have the above haze value. The above haze value can be measured, for example, using a haze meter based on JIS K 7136. Also, it is preferable that the haze value of the above thermosetting resin composition after thermosetting is within the above range. When the haze value after the above thermosetting is within the above range, it is excellent in light transmittance and is preferable for use in image display devices.

[0071] The Shore D hardness of the above thermosetting resin composition after thermosetting is preferably 50 to 100, more preferably 60 to 97, and even more preferably 70 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 based on ASTM D-2240.

[0072] When the above thermosetting resin composition is thermoset in a state of being bonded to a wafer with a thickness of 100 μm, the amount of warp of the wafer after thermosetting relative to before thermosetting is preferably 4 mm or less, more preferably 3 mm or less, and even more preferably 1 mm or less. When the amount of warp is 4 mm or less, the sealing property of the optical semiconductor element is more excellent after thermosetting. The amount of warp is obtained by bonding the sheet-like thermosetting resin composition to a wafer with a thickness of 100 μm, setting the warp of the wafer before thermosetting to 0 mm, and measuring the amount of warp of the wafer when the thermosetting resin composition is thermoset.

[0073] The light transmittance of the above thermosetting resin composition at a wavelength of 400 nm is preferably 85% or more, more preferably 90% or more. When the light transmittance is 85% or more, it has excellent light transmittance and is preferable for use in image display devices. In addition, the above thermosetting resin composition can, for example, not contain a curing agent or minimize its blending ratio, and can be produced with a simple configuration, so it is possible to achieve the above light transmittance. Further, it is preferable that the light transmittance at a wavelength of 400 nm after storage at 125°C for 1000 hours after curing of the above thermosetting resin composition is within the above range.

[0074] The ratio [after curing / before curing] of the light transmittance of the above thermosetting resin composition after curing to the light transmittance before curing is preferably 0.95 or more. When the ratio is 0.95 or more, coloring such as whitening and yellowing hardly occurs before and after thermosetting, it has excellent light transmittance, and is preferable for use in image display devices.

[0075] The shear loss modulus G'' of the above thermosetting resin composition (before curing) at 140°C is preferably 0.5 to 40 kPa, more preferably 1 to 20 kPa, and even more preferably 10 to 20 kPa. When the shear loss modulus G'' is 0.5 kPa or more, when the above thermosetting resin composition is bonded to an optical semiconductor element by thermal lamination and when heated during the curing stage, the optical semiconductor element can be moderately embedded, the above thermosetting resin composition is less likely to overflow, and the sealing property of the optical semiconductor element is excellent. Also, when the shear loss modulus G'' is 40 kPa or less, when the above thermosetting resin composition is bonded to an optical semiconductor element by thermal lamination and when heated during the curing stage, the optical semiconductor element can be sufficiently embedded, and the sealing property of the optical semiconductor element is excellent.

[0076] The above shear loss modulus can be obtained by measuring the shear loss modulus of a thermosetting resin composition punched into a cylindrical shape with a diameter of φ8 mm and a thickness of 300 μm under the conditions of a shear mode and a frequency of 1 Hz, and calculating the shear loss modulus at 140°C. The measurement of the above shear loss modulus and the analysis of the measured values can be carried out using a solid viscoelasticity measuring device (trade name "HAAKE MARSIII Rheometer", manufactured by Thermo SCIENTIFIC).

[0077] The tensile storage modulus E' of the above thermosetting resin composition (before curing) at 25°C is preferably 5 to 2000 MPa, more preferably 10 to 1500 MPa, and even more preferably 20 to 1000 MPa. When the tensile storage modulus E' is 5 MPa or more, the cuttability is excellent when punching the above thermosetting resin composition before heat curing. When the tensile storage modulus E' is 2000 MPa or less, since it has appropriate flexibility, chipping and cracking of the above thermosetting resin composition are less likely to occur during handling, and the handling property is excellent.

[0078] After curing of the above thermosetting resin composition, the tensile storage modulus E' at 150 °C is preferably 0.05 to 20 MPa, more preferably 0.1 to 10 MPa, and even more preferably 0.15 to 5 MPa. When the tensile storage modulus E' is 0.05 MPa or more, the cured thermosetting resin composition has a certain degree of hardness, and the adhesion between the side surfaces of adjacent optical semiconductor devices in the tiling state is low. When separating adjacent optical semiconductor devices from each other, the defect of the sheet on the side surface of the optical semiconductor device and the adhesion of the sheet of the adjacent optical semiconductor device are less likely to occur. When the tensile storage modulus E' is 20 MPa or less, when the optical semiconductor element is sealed, the difference in the linear expansion coefficient between the cured product of the thermosetting resin composition and the substrate is small, and warping is less likely to occur.

[0079] After curing of the above thermosetting resin composition, the glass transition temperature (Tg) is preferably 10 to 150 °C, more preferably 20 to 100 °C, and even more preferably 20 to 60 °C. When the Tg is 10 °C or more, the surface has excellent scratch resistance. When the Tg is 150 °C or less, the thermosetting resin composition is less likely to warp after heat curing and has excellent sealing properties for optical semiconductor elements. The glass transition temperature can be calculated using a dynamic viscoelasticity measurement (DMA) device.

[0080] For the above thermosetting resin composition, the tanδ at the glass transition temperature after curing is preferably 0.1 to 5, more preferably 0.7 to 1.5, and even more preferably 1.0 to 1.5. When the tanδ is 0.1 or more, the thermosetting resin composition is less likely to warp after heat curing and has excellent sealing properties for optical semiconductor elements. When the tanδ is 5 or less, the surface has excellent scratch resistance. The tanδ can be calculated using a dynamic viscoelasticity measurement (DMA) device.

[0081] The above thermosetting resin composition may be provided on the surface of the base material portion. In this case, the base material portion serves as a support for the thermosetting resin composition, and by providing the base material portion, the thermosetting resin composition has excellent handleability. Note that a sheet including the base material portion and the thermosetting resin composition provided on one surface of the base material portion may be referred to as a sheet for encapsulating an optical semiconductor element.

[0082] Further, the thermosetting resin composition may include a release liner on at least one of its surfaces (for example, the surface opposite to the base material portion when having the base material portion). The release liner is used as a protective material for the thermosetting resin composition and is peeled off when an optical semiconductor element is encapsulated using the thermosetting resin composition. Note that the release liner does not necessarily have to be provided.

[0083] 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 bonded to a substrate on which an optical semiconductor element is disposed.

[0084] Examples of the release liner include a polyethylene terephthalate (PET) film, a polyethylene film, a polypropylene film, a plastic film or paper surface-coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent.

[0085] The thickness of the release liner is, for example, 10 to 200 μm, preferably 15 to 150 μm, more preferably 20 to 100 μm. When the thickness is 10 μm or more, it is difficult to break due to cuts during the processing of the release liner. When the thickness is 200 μm or less, it is easier to peel the release liner from the thermosetting resin composition during use.

[0086] [Sheet for Encapsulating Optical Semiconductor Element] The sheet for encapsulating an optical semiconductor element includes the base material portion and the sheet-like thermosetting resin composition provided on one surface of the base material portion.

[0087] Hereinafter, an embodiment of the sheet for encapsulating an optical semiconductor element will be described. FIG. 1 is a cross-sectional view showing an embodiment of a sheet for encapsulating an optical semiconductor element including the thermosetting resin composition of the present invention. As shown in FIG. 1, the sheet 1 for encapsulating an optical semiconductor element can be used to encapsulate one or more optical semiconductor elements disposed on a substrate, and includes a base material portion 2, a sheet-like thermosetting resin composition 3, and a release liner 4. The thermosetting resin composition 3 is provided on one surface of the base material portion 2. The release liner 4 is attached to the surface of the thermosetting resin composition 3 (the surface opposite to the side having the base material portion 2). In other words, the sheet 1 for encapsulating an optical semiconductor element includes the base material portion 2, the thermosetting resin composition 3, and the release liner 4 in this order. The base material portion 2 is a multilayer having an optical film 21 and a plastic film 23, and the optical film 21 and the plastic film 23 are bonded via an adhesive layer 22.

[0088] <Base material portion> The above base material portion may be a single layer, or may be a multilayer having the same or different compositions and thicknesses. When the above base material portion is a multilayer, each layer may be bonded by another layer such as an adhesive layer. Note that the base material layer used for the base material portion is a portion that is attached to the substrate including the optical semiconductor element together with the thermosetting resin composition when encapsulating the optical semiconductor element with the thermosetting resin composition, and the release liner that is peeled off during the use (attachment) of the thermosetting resin composition and the surface protection film that only protects the surface of the base material portion are not included in the "base material portion".

[0089] Examples of the base material layer constituting the base material portion include glass and plastic base materials (particularly plastic films). Examples of the resin constituting the plastic base material include polyolefin resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypropylene, polybutene, polymethylpentene, ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate (random, alternating) copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-propylene copolymer, cyclic olefin polymer, ethylene-butene copolymer, ethylene-hexene copolymer; polyurethane; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate (PBT); polycarbonate; polyimide resins; polyether ether ketone; polyether imide; polyamides such as aramid and wholly aromatic polyamide; polyphenyl sulfide; fluororesin; polyvinyl chloride; polyvinylidene chloride; cellulose resins such as triacetyl cellulose (TAC); silicone resins; acrylic resins such as polymethyl methacrylate (PMMA); polysulfone; polyarylate; polyvinyl acetate, etc. The above resins may be used alone or in combination of two or more.

[0090] The base material layer may be various optical films such as an antireflection (AR) film, a polarizing plate, a retardation plate, etc. When the base material portion has an optical film, the base material layer can be directly applied to the optical member.

[0091] The plastic film preferably contains a polyester resin and / or a polyimide resin as a main component (the component with the highest mass ratio among the constituent resins). By having such a configuration, the base material portion is excellent in heat resistance, can suppress the thermal expansion of the base material portion in a high-temperature environment, and improves dimensional stability. In addition, since rigidity as a sheet can be imparted, handleability and retainability are improved.

[0092] 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 sheet for sealing the optical semiconductor element are further improved. When the thickness is 200 μm or less, the optical semiconductor device can be made thinner.

[0093] The base material portion 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 inferior in supportability and handleability, and by using them in combination with the plastic film, the advantages of both can be utilized. In this case, in particular, in the base material portion, it is preferable that the plastic film is on the thermosetting resin composition side.

[0094] The base material portion preferably includes a layer having antiglare properties and / or antireflection properties. The layer having antiglare properties and / or antireflection properties can be obtained as an antiglare treatment layer or an antireflection treatment layer, for example, by performing an antiglare treatment and / or an antireflection treatment on at least one surface of the base material layer. The antiglare treatment layer and the antireflection treatment layer may be the same layer or different layers from each other. The antiglare treatment and the antireflection treatment can each be carried out by known or conventional methods.

[0095] The surface of the base material portion on the side provided with the thermosetting resin composition may be subjected to surface treatment such as physical treatment such as corona discharge treatment, plasma treatment, sand mat processing treatment, ozone exposure treatment, flame exposure treatment, high-voltage electric shock exposure treatment, ionization radiation treatment; chemical treatment such as chromic acid treatment; easy adhesion treatment with a coating agent (primer) for the purpose of enhancing the adhesion and retention with the thermosetting resin composition. The surface treatment for enhancing the adhesion is preferably applied to the entire surface of the base material portion on the thermosetting resin composition side.

[0096] From the viewpoint of excellent functions as a support and scratch resistance of the surface, the thickness of the base material portion is preferably 5 μm or more, more preferably 10 μm or more. From the viewpoint of better transparency, the thickness of the base material portion is preferably 300 μm or less, more preferably 200 μm or less.

[0097] The base material portion may be provided with a surface protection film on the surface (the surface opposite to the thermosetting resin composition). When using the optical film as the base material portion, for example, the optical film can be protected until it is used. Note that the surface protection film does not necessarily have to be provided.

[0098] The thermosetting resin composition may be produced by forming the thermosetting resin composition on the release treatment surface of the release sheet. Further, the base material portion or a separate release sheet may be laminated on the surface of the thermosetting resin composition. Also, the thermosetting resin composition may be formed on the base material portion. Further, the release sheet may be laminated on the surface of the thermosetting resin composition. The thermosetting resin composition can be produced by applying a resin composition for forming the thermosetting resin composition on the release treatment surface of the release sheet or on the base material portion to form a resin composition, and then performing solvent removal or curing by heating, or curing by irradiation with active energy rays to solidify the resin composition. When heating is performed, the formed thermosetting resin composition should be in a state that can be thermally cured when encapsulating the optical semiconductor element. Examples of the coating method of the resin composition include roll coating, screen coating, gravure coating, and the like.

[0099] Using the above thermosetting resin composition or the above sheet for encapsulating an optical semiconductor device, the thermosetting resin composition is bonded onto a substrate on which an optical semiconductor element is disposed, and the optical semiconductor element is encapsulated with the thermosetting resin composition, whereby an optical semiconductor device can be obtained. Specifically, first, the release liner is peeled off as necessary to expose the thermosetting resin composition. Then, the exposed surface of the thermosetting resin composition is bonded to the substrate surface of the optical member including the substrate and the optical semiconductor element (preferably a plurality of optical semiconductor elements) disposed on the substrate. When the optical member includes a plurality of optical semiconductor elements, the thermosetting resin composition is further arranged so as to fill the gaps between the plurality of optical semiconductor elements, and the plurality of optical semiconductor elements are embedded together. Thereafter, the thermosetting resin composition is heated and cured to encapsulate the optical semiconductor element. In this way, the optical semiconductor element can be encapsulated using the above thermosetting resin composition or the above sheet for encapsulating an optical semiconductor device. Further, the optical semiconductor element may be embedded by bonding under a reduced pressure environment or while applying pressure using the above thermosetting resin composition or the above sheet for encapsulating an optical semiconductor device. Examples of such a method include the methods disclosed in JP-A-2016-29689 and JP-A-6-97268.

[0100] [Optical Semiconductor Device] An optical semiconductor device can be fabricated using the above thermosetting resin composition. The optical semiconductor device manufactured using the above thermosetting resin composition includes a substrate, an optical semiconductor element disposed on the substrate, and a cured product obtained by curing the thermosetting resin composition that encapsulates the optical semiconductor element. The cured product is a cured product obtained by thermally curing the thermosetting resin composition. Specifically, it includes a cured encapsulation layer obtained by thermally curing the thermosetting resin composition.

[0101] Examples of the above 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.

[0102] In the above optical semiconductor device, since the thermosetting resin composition is excellent in followability to unevenness when the optical semiconductor element is a convex portion and the gaps between a plurality of optical semiconductor elements are concave portions, and is excellent in embedability of the optical semiconductor element, it is preferable to encapsulate the plurality of optical semiconductor elements collectively.

[0103] FIG. 2 shows an 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 disposed on one surface of the substrate 5, and a cured product 1' of an 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 thermosetting the thermosetting resin composition 3 to form a cured encapsulation layer 3'. The plurality of optical semiconductor elements 6 are collectively encapsulated in the cured encapsulation layer 3'. The cured encapsulation layer 3' follows the uneven shape formed by the plurality of optical semiconductor elements 6 and adheres closely to the optical semiconductor elements 6 and the substrate 5, embedding the optical semiconductor elements 6.

[0104] As described above, the above optical semiconductor device encapsulates the optical semiconductor element with the cured encapsulation layer. After the thermosetting of the above thermosetting resin composition, it is excellent in light transmittance and can efficiently transmit the light emitted by the optical semiconductor element. Further, after the thermosetting of the above thermosetting resin composition, it is excellent in heat resistance. Therefore, even when the image display device generates heat after encapsulating the optical semiconductor element or when heated during the reflow process after encapsulation, the shape of the cured encapsulation layer is less likely to change. Further, the above thermosetting resin composition has sufficient flexibility before thermosetting, so it is excellent in unevenness followability, sufficiently embeds the optical semiconductor element, and fixes the optical semiconductor element after thermosetting. Therefore, the optical semiconductor element adheres closely to the cured encapsulation layer, and the encapsulation property of the optical semiconductor element is excellent. Furthermore, since the side surface of the cured encapsulation layer has low adhesiveness, when separating adjacent optical semiconductor devices in a tiled state, they can be easily separated, and sheet breakage or adhesion of the sheets of adjacent optical semiconductor devices is less likely to occur.

[0105] The above optical semiconductor device may be one in which individual optical semiconductor devices are tiled. That is, the above optical semiconductor device may be one in which a plurality of optical semiconductor devices are arranged in a tile shape in the planar direction.

[0106] FIG. 3 shows an embodiment of an optical semiconductor device fabricated by arranging a plurality of optical semiconductor devices. The optical semiconductor device 20 shown in FIG. 3 is one in which a total of 16 optical semiconductor devices 10, 4 in the vertical direction and 4 in the horizontal direction, are arranged in a tile shape in the planar direction (tiling). At the boundary 20a between two adjacent optical semiconductor devices 10, the optical semiconductor devices 10 are adjacent to each other, but they can be easily separated, and it is difficult for defects to occur on the side surface of the cured encapsulation layer 3', or for the resin that is missing on the side surface of the cured encapsulation layer 3' to adhere from one of the adjacent optical semiconductor devices to the other.

[0107] The above optical semiconductor device is preferably a backlight for a liquid crystal screen, and particularly preferably a full-array direct-lit backlight. Further, an image display device can be formed by combining the above backlight and a display panel. When the above optical semiconductor device is a backlight for a liquid crystal screen, the optical semiconductor element is an LED element. For example, in the above backlight, a metal wiring layer for sending a light emission control signal to each LED element is laminated on the above substrate. Each LED element that emits light of each color of red (R), green (G), and blue (B) is alternately arranged on the substrate of the display panel via the metal wiring layer. The metal wiring layer is formed of a metal such as copper, reflects the light emission of each LED element, and reduces the visibility of the image. Also, the light emitted by each LED element of each color of RGB is mixed, reducing the contrast.

[0108] Furthermore, the above optical semiconductor device is preferably an organic light-emitting display device. Further, an image display device can be formed by combining the above organic light-emitting display device and a display panel as needed. When the above optical semiconductor device is an organic light-emitting display device, the optical semiconductor element is an LED element. Examples of the above organic light-emitting display device include an organic electroluminescence (organic EL) display device and the above backlight. For example, in the above organic light-emitting display device, a metal wiring layer for sending a light emission control signal to each LED element is laminated on the substrate. Each LED element that emits light of each color of red (R), green (G), and blue (B) is alternately arranged on the substrate via the metal wiring layer. The metal wiring layer is formed of a metal such as copper, and adjusts the light emission intensity of each LED element to display each color.

[0109] The above thermosetting resin composition and the sheet for sealing the optical semiconductor element can be used for an optical semiconductor device that is used in a bent state, for example, an optical semiconductor device having a foldable image display device (flexible display) (particularly, a foldable image display device (foldable display)). Specifically, it can be used for a foldable backlight and a foldable organic light-emitting display device.

[0110] Since the above thermosetting resin composition and the sheet for sealing the optical semiconductor element are excellent in the sealing property of the optical semiconductor element, they can be preferably used in both the case where the above optical semiconductor device is a mini-LED display device and the case where it is a micro-LED display device.

[0111] [Method for manufacturing an optical semiconductor device] The above-mentioned optical semiconductor device can be manufactured, for example, by a manufacturing method including a step of bonding the above-mentioned sheet for encapsulating the optical semiconductor element to the above-mentioned optical semiconductor element provided on the above-mentioned substrate and embedding the above-mentioned optical semiconductor element with the above-mentioned thermosetting resin composition (embedding step), and a step of heating a laminate including the above-mentioned substrate, the above-mentioned optical semiconductor element disposed on the above-mentioned substrate, and the above-mentioned sheet for encapsulating the above-mentioned optical semiconductor element to cure the above-mentioned thermosetting resin composition to obtain a cured product (heating step). The above-mentioned cured product is a cured product obtained by thermally curing the above-mentioned thermosetting resin composition, and specifically includes a cured encapsulation layer obtained by thermally curing the above-mentioned thermosetting resin composition.

[0112] The above-mentioned manufacturing method may further include a step of dicing the above-mentioned laminate after the above-mentioned heating step to obtain an optical semiconductor device (dicing step). Further, the above-mentioned manufacturing method may further include a tiling step of arranging a plurality of optical semiconductor devices obtained in the above-mentioned dicing step in contact with each other in a planar direction. Hereinafter, the manufacturing method of the optical semiconductor device 10 shown in FIG. 2 and the optical semiconductor device 20 shown in FIG. 3 will be described with appropriate reference.

[0113] (Embedding step) In the above embedding step, the sheet for encapsulating the optical semiconductor element is bonded to the substrate on which the optical semiconductor element is disposed, and the optical semiconductor element is encapsulated with the thermosetting resin composition. In the above embedding step, specifically, as shown in FIG. 4, the thermosetting resin composition 3 of the sheet 1 for encapsulating the optical semiconductor element from which the release liner 4 has been peeled is disposed so as to face the surface of the substrate 5 on which the optical semiconductor element 6 is disposed, and the sheet 1 for encapsulating the optical semiconductor element is bonded 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. 5. For the purpose of trimming the ends and making the sizes uniform in the dicing step, as shown in FIG. 4, the substrate 5 used for bonding extends wider in the plane 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 ends of the substrate 5. Further, the sheet 1 for encapsulating the optical semiconductor element to be bonded extends wider in the plane direction than the substrate 5 used for bonding. That is, the area of the surface of the sheet 1 for encapsulating the optical semiconductor element facing the substrate 5 to be bonded in the embedding step is larger than the area of the surface of the substrate 5 facing the sheet 1 for encapsulating the optical semiconductor element to be bonded in the embedding step.

[0114] The temperature during the above bonding is, for example, within the range from room temperature to 150°C. Further, during the above bonding, depressurization or pressurization may be performed. It is possible to suppress the formation of voids between the thermosetting resin composition and the substrate or the optical semiconductor element due to depressurization or pressurization. Further, in the above embedding step, it is preferable to bond the sheet for encapsulating the optical semiconductor element under reduced pressure and then pressurize it. The pressure in the case of depressurization is, for example, 1 to 100 Pa, and the depressurization time is, for example, 5 to 600 seconds. Further, the pressure in the case of pressurization is, for example, 0.05 to 0.5 MPa, and the pressurization time is, for example, 5 to 600 seconds.

[0115] (Heating Step) In the above heating process, the laminate in which the sheet for sealing the optical semiconductor element is bonded to the substrate on which the optical semiconductor element is disposed (for example, the laminate obtained in the above embedding process) is heated to cure the thermosetting resin composition. In the above heating process, specifically, as shown in FIG. 6, the thermosetting resin composition 3 is cured to form a cured sealing layer 3', and a cured product 1' of the sheet for sealing the optical semiconductor element 1 is obtained. The temperature during the above heating is, for example, in the range of 80 to 200 °C, and the heating time is, for example, 1 minute to 24 hours.

[0116] (Dicing process) In the above dicing process, the laminate that has undergone the above heating process is diced. Here, in the laminate subjected to the dicing process, the cured product 1' of the sheet for sealing the optical semiconductor element and the substrate 5 extend wider in the planar direction than the finally obtained optical semiconductor device 10, as described above. Then, in the above dicing process, the side end portions of the cured product of the sheet for sealing the optical semiconductor element and the substrate are diced and removed. Specifically, dicing is performed at the position of the dashed line shown in FIG. 7 to remove the side end portions. The above dicing can be performed by a known or conventional method, for example, a method using a dicing blade or a method using laser irradiation. In this way, for example, the optical semiconductor device 10 shown in FIG. 2 can be manufactured.

[0117] (Tiling process) In the above tiling process, a plurality of optical semiconductor devices obtained in the above dicing process are tiled by arranging them in contact with each other in the planar direction. In this way, 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 of the optical semiconductor element, and when separating adjacent optical semiconductor devices from each other, sheet defects and adhesion of the sheets of adjacent optical semiconductor devices are less likely to occur.

Examples

[0118] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples in any way.

[0119] Example 1 100 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 (in terms of solid content) of a silica filler (trade name “MEK-ST-40”, manufactured by Nissan Chemical Industries, Ltd.) were dissolved in methyl ethyl ketone to prepare a resin composition solution 1 having a solid content concentration of 20% by mass. After applying the resin composition solution 1 onto the release-treated surface of a release liner (a release-treated film made of a polyethylene terephthalate film having a thickness of 50 μm and subjected to a silicone release treatment), it was dried at 130° C. for 2 minutes to produce a sheet-like thermosetting resin composition 1 having a thickness (average thickness) of 20 μm.

[0120] Example 2 100 parts by mass of an 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 (in terms of solid content) of a silica filler (trade name “MEK-ST-40”, manufactured by Nissan Chemical Industries, Ltd.) were dissolved in methyl ethyl ketone to prepare a resin composition solution 2 having a solid content concentration of 20% by mass. After applying the resin composition solution 2 onto the release-treated surface of a release liner (a release-treated film made of a polyethylene terephthalate film having a thickness of 50 μm and subjected to a silicone release treatment), it was dried at 130° C. for 2 minutes to produce a sheet-like thermosetting resin composition 2 having a thickness (average thickness) of 20 μm.

[0121] Example 3 100 parts by mass of an 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 an 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 a resin composition solution 3 having a solid content concentration of 20% by mass. The above resin composition solution 3 was applied onto the release-treated surface of a release liner (a release-treated film made of a polyethylene terephthalate film with a thickness of 50 μm and silicone release treatment), and then dried at 130°C for 2 minutes to produce a sheet-like thermosetting resin composition 3 with a thickness (average thickness) of 20 μm.

[0122] Example 4 100 parts by mass of an 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 an 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 an acrylic resin (GMA:butyl acrylate (BA) = 18% by mass:82% by mass, weight average molecular weight 0.25×10⁴) were dissolved in methyl ethyl ketone to prepare a resin composition solution 4 with a solid content concentration of 20% by mass. The above resin composition solution 4 was applied onto the release-treated surface of a release liner (a release-treated film made of a polyethylene terephthalate film with a thickness of 50 μm and silicone release treatment), and then dried at 130°C for 2 minutes to produce a sheet-like thermosetting resin composition 4 with a thickness (average thickness) of 20 μm.

[0123] Comparative Example 1 100 parts by mass of an 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 a phenol resin (trade name "MEHC-7500", manufactured by Meiwa Kasei Co., Ltd.), 53 parts by mass of an epoxy resin (trade name "EPPN501HY", manufactured by Nippon Kayaku Co., Ltd.), and 120 parts by mass (in terms of solid content) of a silica filler (trade name "MEK-ST-40", manufactured by Nissan Chemical Industries, Ltd.) were dissolved in methyl ethyl ketone to prepare a resin composition solution 5 with a solid content concentration of 20% by mass. The above resin composition solution 5 was applied onto the release-treated surface of a release liner (a release-treated film made of a polyethylene terephthalate film with a thickness of 50 μm and silicone release treatment), and then dried at 130°C for 2 minutes to produce a sheet-like thermosetting resin composition 5 with a thickness (average thickness) of 20 μm.

[0124] Comparative Example 2 100 parts by mass of an 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 a phenol resin (trade name "MEHC-7500", manufactured by Meiwa Kasei Co., Ltd.), and 59 parts by mass of an epoxy resin (trade name "JER828", manufactured by Mitsubishi Chemical Corporation) were dissolved in methyl ethyl ketone to prepare a resin composition solution 6 having a solid content concentration of 20% by mass. After applying the resin composition solution 6 onto the release-treated surface of a release liner (a release-treated film made of a polyethylene terephthalate film having a thickness of 50 μm and subjected to a silicone release treatment), it was dried at 130°C for 2 minutes to produce a sheet-like thermosetting resin composition 6 having a thickness (average thickness) of 20 μm.

[0125] Comparative Example 3 100 parts by mass of an 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 a phenol resin (trade name "MEHC-7500", manufactured by Meiwa Kasei Co., Ltd.), 287 parts by mass of an epoxy resin (trade name "EPPN501HY", manufactured by Nippon Kayaku Co., Ltd.), and 470 parts by mass (in terms of solid content) of a silica filler (trade name "SO-25R", manufactured by Admatechs Co., Ltd.) were dissolved in methyl ethyl ketone to prepare a resin composition solution 7 having a solid content concentration of 20% by mass. After applying the resin composition solution 7 onto the release-treated surface of a release liner (a release-treated film made of a polyethylene terephthalate film having a thickness of 50 μm and subjected to a silicone release treatment), it was dried at 130°C for 2 minutes to produce a sheet-like thermosetting resin composition 7 having a thickness (average thickness) of 20 μm.

[0126] <Evaluation> The following evaluations were performed on the thermosetting resin compositions obtained in the examples and comparative examples. The results are shown in a table.

[0127] (1) Shear loss modulus at 140°C The thermosetting resin compositions obtained in the examples and comparative examples were laminated to produce a laminate of the thermosetting resin composition with a thickness of about 300 μm, which was punched into a cylindrical shape with a diameter of φ8 mm to obtain a measurement sample. Using a rheometer (trade name "HAAKE MARSIII Rheometer", manufactured by Thermo SCIENTIFIC), the above measurement sample was measured in a shear mode at a frequency of 1 Hz and a heating rate of 5 °C / min in the range of 80 to 160 °C, and the shear loss elastic modulus at 140 °C was calculated.

[0128] (2) Tensile storage elastic modulus at 25 °C The thermosetting resin compositions obtained in the examples and comparative examples were stacked under the condition of 60 °C until the thickness reached 200 μm, and then cut into strip shapes with a width of 10 mm × a length of 40 mm using a cutter knife to obtain measurement samples. Using a solid viscoelasticity measuring device (trade name "RSAIII", manufactured by Rheometric Scientific), the above measurement samples were measured in a tensile mode at a frequency of 1 Hz and a chuck distance of 22.5 mm, and the dynamic storage elastic modulus was measured at a heating rate of 5 °C / min in the range of -30 to 250 °C, and the tensile storage elastic modulus at 25 °C was calculated.

[0129] (3) Tensile storage elastic modulus at 150 °C after curing The thermosetting resin compositions obtained in the examples and comparative examples were stacked under the condition of 60 °C until the thickness reached 200 μm, and then cut into strip shapes with a length of 40 mm × a width of 10 mm using a cutter knife. After that, the samples cured by heating at 150 °C for 1 hour were used as measurement samples. Using a solid viscoelasticity measuring device (trade name "RSAIII", manufactured by Rheometric Scientific), the above measurement samples were measured in a tensile mode at a chuck distance of 22.5 mm and a frequency of 1 Hz, and the dynamic storage elastic modulus was measured at a heating rate of 5 °C / min in the range of -30 to 250 °C, and the tensile storage elastic modulus at 150 °C was calculated.

[0130] (4) Glass transition temperature and tanδ after curing The thermosetting resin compositions obtained in the examples and comparative examples were stacked under the condition of 60 °C until the thickness reached 200 μm, and then strip-shaped measurement pieces with a length of 40 mm and a width of 10 mm 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 in the range of -30 to 250 °C at a heating rate of 5 °C / min under the conditions of a chuck distance of 22.5 mm and a frequency of 1 Hz, and the glass transition temperature was calculated from the peak value of tanδ. Also, the peak value was obtained as the tanδ of the glass transition temperature.

[0131] (5) Light transmittance (before curing) Regarding the thermosetting resin compositions obtained in the examples and comparative examples, those with a thickness of 50 μm were separately prepared in the same manner and used as measurement samples. Then, using an ultraviolet-visible-near-infrared spectrophotometer (trade 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.

[0132] (6) Light transmittance (after curing) Regarding the thermosetting resin compositions obtained in the examples and comparative examples, those with a thickness of 50 μm were separately prepared in the same manner, then heated at 150 °C for 1 hour to cure, and further stored at 125 °C for 1000 hours and used as measurement samples. Then, using an ultraviolet-visible-near-infrared spectrophotometer (trade 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.

[0133] (7) Haze value For the thermosetting resin compositions obtained in the examples and comparative examples, those having a thickness of 50 μm were separately prepared in the same manner, and then heated at 150°C for 1 hour to cure, and further stored at 125°C for 1000 hours to obtain measurement samples. Then, they were set in the sample chamber of a turbidimeter (trade name "NDHG2000", manufactured by Nippon Denshoku Industries Co., Ltd.), and the haze value was measured using a light source D65.

[0134] (8) Shore D hardness The thermosetting resin compositions obtained in the examples and comparative examples were laminated to prepare a laminate of the thermosetting resin composition with a thickness of 3 mm, heated at 150°C for 1 hour and then at 175°C for 1 hour to cure, and measurement samples were prepared. Then, the Shore D hardness was measured using a type D indenter of a durometer.

[0135] (9) Warpage amount The thermosetting resin compositions obtained in the examples and comparative examples were bonded to a wafer with a thickness of 100 μm, heated at 150°C for 1 hour to cure, and measurement samples were prepared. Then, the warpage of the wafer before thermosetting was set to 0 mm, and the warpage amount of the wafer when the above thermosetting resin composition was thermoset was measured.

[0136] (10) Embedding property The thermosetting resin compositions obtained in the examples and comparative examples were bonded to a 10 mm × 10 mm × 200 μm mirror chip under the conditions of a temperature of 80°C, a pressure of 0.3 MPa, and a bonding speed of 10 mm / sec. Then, using a die bonder (trade name "Die Bonder SPA-300", manufactured by Shinagawa Co., Ltd.), it was bonded to a BGA substrate with a surface unevenness of 10 μm under the conditions of a stage temperature of 140°C, a die bond load of 0.2 MPa, and a die bond time of 2 seconds. Then, the voids between the thermosetting resin composition and the substrate were observed using an ultrasonic imaging device (trade name "FineSAT III", manufactured by Hitachi Power Solutions Co., Ltd.). The area occupied by the voids in the observation image was calculated using binary software "WinRoof ver.5.6". Also, the distance of the thermosetting resin composition protruding from the chip was measured with an optical microscope. Then, the embedding property 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 amount of protrusion 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 amount of protrusion is 100 μm or more.

[0137] (11) Dicing evaluation For the thermosetting resin compositions obtained in the examples and comparative examples, with respect to the pattern surface of a substrate (trade name "Lead-free Universal Substrate ICB93SGPBF", manufactured by Sunhayato Co., Ltd.), the entire surface of the thermosetting resin composition exposed by peeling the release liner was bonded with a hand roller to prepare test samples. Note that the bonding area of the thermosetting resin composition is larger than the area of the substrate to be bonded. The bonding was carried out in an environment of temperature 22°C and humidity 50% so that no bubbles were introduced. Then, it was heated at 150°C for 1 hour to cure the thermosetting resin composition.

[0138] After heat curing, a dicing tape (trade name "NBD-5172K", manufactured by Nitto Denko Corporation) was attached to the surface of the substrate on the side where the thermosetting resin composition of the test sample was not attached. A dicing ring for dicing was attached to the adhesive surface of the dicing tape. After attachment, it was left standing for 30 minutes in a light-shielded environment and at a temperature of 22°C. Then, under the following dicing conditions, blade dicing was performed on the laminate of the test sample and the dicing tape from the side edge of the substrate toward the inside at a position 5 mm from the side edge. <Dicing conditions> Dicing apparatus: Trade name "DFD-6450", manufactured by DISCO Corporation Cutting method: Single cut Dicing speed: 30 mm / second Dicing blade: Trade name "P1A861 SDC400N75BR597", manufactured by DISCO Corporation Dicing blade rotation speed: 30,000 rpm Blade height: 85 μm Water volume: 1.5 L / minute Dicing interval: 10 mm Distance of one-time dicing: the full length of the test sample

[0139] Note that the blade used for dicing was the one processed by dressing dicing in 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 the dicing tape (product name "NBD-7163K", manufactured by Nitto Denko Corporation) to prepare a work for processing. Next, the obtained work was diced under the following dressing dicing conditions to obtain the blade for the above blade dicing. <Dressing dicing conditions> Dicing device: product name "DFD-6450", manufactured by DISCO Corporation Cutting method: single cut Dicing speed: 55 mm / second Dicing blade: product name "P1A861 SDC400N75BR597" (new product), manufactured by DISCO Corporation Rotation speed of dicing blade: 35,000 rpm Blade height: 500 μm Water volume: 1.5 L / minute Distance of one-time dicing: the full length of the board Dicing interval: in 1 mm increments Number of dicing times: 100 times

[0140] Thereafter, the dicing surfaces of the laminate of the test sample and the substrate cut into strips by blade dicing were checked to confirm whether there was any stickiness. Those with stickiness confirmed were marked as "×", and those that could be confirmed were evaluated as "○".

[0141]

Table 1

[0142] As shown in Table 1, the thermosetting resin composition (Example) of the present invention was evaluated to have a high light transmittance and excellent light transmittance after curing. Further, it was evaluated to have excellent heat resistance, a small warpage amount, and good dicing properties. Furthermore, it was evaluated to have good embedding properties and excellent sealing properties for the optical semiconductor element. On the other hand, when the content ratio of the acrylic resin in the thermosetting resin composition was low (Comparative Example), the light transmittance after curing was low and it was evaluated to be inferior in light transmittance. Also, there were cases where the embedding properties and dicing properties were inferior, the warpage amount was large, and the heat resistance was inferior.

Explanation of Signs

[0143] 1 Sheet for sealing optical semiconductor element 1’ Cured product of sheet for sealing optical semiconductor element 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 element 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 contains an acrylic resin as an organic component, A thermosetting resin composition, wherein the content of the acrylic resin in the organic component is 85 mass% or more.

2. The thermosetting resin composition according to claim 1 , wherein the acrylic resin comprises a glycidyl group-containing acrylic resin.

3. The thermosetting resin composition according to claim 2, wherein the glycidyl group-containing acrylic resin contains a constituent unit derived from a glycidyl group-containing (meth)acrylic acid ester, and a content ratio of the constituent unit derived from the glycidyl group-containing (meth)acrylic acid ester in the glycidyl group-containing acrylic resin is 5 to 50 mass%.

4. The thermosetting resin composition according to claim 2 or 3, wherein the weight average molecular weight of the glycidyl group-containing acrylic resin is 2,000 to 400,000, and the content of the glycidyl group-containing acrylic resin in the organic component is 40 mass% or more.

5. The thermosetting resin composition according to any one of claims 1 to 4, which has a haze value after heat curing of 0.1 to 1.0%.

6. The thermosetting resin composition according to any one of claims 1 to 5, which has a Shore D hardness of 50 to 100 after heat curing.

7. The thermosetting resin composition according to any one of claims 1 to 6, wherein when the composition is heat-cured in a state where the composition is laminated to a wafer having a thickness of 100 µm, the amount of warping of the wafer after heat-curing is 4 mm or less compared to before heat-curing.

8. The thermosetting resin composition according to any one of claims 1 to 7, which has a light transmittance of 85% or more at a wavelength of 400 nm.

9. 9. 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.

10. 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 9, which seals the optical semiconductor element.

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

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

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

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

Images