Sheet for sealing optical semiconductor element, and optical semiconductor device

Abstract

The invention relates to a sheet for sealing an optical semiconductor element and an optical semiconductor device. Provided is a sheet for sealing an optical semiconductor element, said sheet being capable of sufficiently filling a gap between an optical semiconductor element and a substrate when sealing the optical semiconductor element, and being not susceptible to the formation of a gap between a plurality of optical semiconductor elements. A sheet (1) for sealing an optical semiconductor element is a sheet for sealing one or more optical semiconductor elements (6) disposed on a substrate (5). A sheet (1) for sealing an optical semiconductor element has a sealing resin layer (2) containing at least a curable resin layer (X) (21) and an adhesive layer (22). The viscosity of the curable resin layer (X) (21) at the sealing temperature is from 2 kPa * s to 2000 kPa * s.

Description

Technical Field

[0001] The present invention relates to a sheet for encapsulating an optical semiconductor element and an optical semiconductor device. More specifically, the present invention relates to a sheet suitable for encapsulating an optical semiconductor element and an optical semiconductor device having a structure in which the sheet encapsulates the optical semiconductor element. Background Art

[0002] Self-luminous display devices, such as mini / micro LED displays, are known to have a structure in which multiple LEDs are arranged on a substrate and sealed with a sealing resin. A known method for collectively sealing the multiple LEDs with the sealing resin is to inject liquid resin into the area where the multiple LEDs are arranged to bury the multiple LEDs, and then cure the liquid resin by heat or ultraviolet irradiation.

[0003] However, the method of sealing optical semiconductor elements such as LEDs using liquid resin has problems with poor workability, such as dripping during application and adhesion of the liquid resin to undesirable areas. In contrast, it is easy to adapt to a method that does not use liquid resin and instead uses a sealing sheet with a sealing layer for sealing optical semiconductor elements. This allows optical semiconductor elements to be sealed in a short time using a simple process.

[0004] As such a sealing sheet, for example, Patent Document 1 discloses a pressure-sensitive adhesive sheet comprising a laminate of a colored pressure-sensitive adhesive layer and a colorless pressure-sensitive adhesive layer, wherein the colorless pressure-sensitive adhesive layer is located in contact with an optical semiconductor element. Furthermore, Patent Document 2 discloses a resin sheet for sealing electronic components having a curable resin composition layer.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-169262

[0008] Patent Document 2: Japanese Patent Application Publication No. 2019-67852 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] Incidentally, in a flip-chip semiconductor device in which an optical semiconductor element is directly bump-connected to a substrate, for example, a gap exists between the optical semiconductor element and the substrate to which the bump is connected. Liquid resins have been used in the past as sealing resins (underfill materials) capable of filling such gaps. However, as described above, the method using liquid resins has the problem of poor operability, and therefore a sealing sheet with excellent operability is required for use in filling such gaps.

[0011] However, in the sealing sheet comprising an adhesive layer as disclosed in Patent Document 1, the adhesive layer has low fluidity, making it difficult to fully fill the gaps between the optical semiconductor element and the substrate. Furthermore, in the sealing sheet comprising a curable resin composition layer disclosed in Patent Document 2, although the aforementioned gaps can be fully filled, the resin composition layer has excessively high fluidity, which sometimes creates gaps between the multiple optical semiconductor elements formed on the substrate, adversely affecting the appearance of the optical semiconductor device.

[0012] The present invention has been made based on the above situation, and its object is to provide a sheet for sealing an optical semiconductor element, which can fully fill the gap between the optical semiconductor element and the substrate when sealing the optical semiconductor element and is unlikely to form gaps between multiple optical semiconductor elements.

[0013] Means used to solve problems

[0014] The present inventors have conducted intensive research to achieve the above-mentioned objectives and have discovered that, when encapsulating optical semiconductor elements, a specific encapsulating sheet can fully fill the gap between the optical semiconductor element and the substrate, while also minimizing the occurrence of gaps between multiple optical semiconductor elements. The present invention has been completed based on these findings.

[0015] That is, the present invention provides a sheet for sealing optical semiconductor elements, which is used to seal one or more optical semiconductor elements arranged on a substrate. The sheet has a sealing resin layer comprising at least a curable resin layer and an adhesive layer, and the viscosity of the curable resin layer at the sealing temperature is 2 kPa·s to 2000 kPa·s.

[0016] It is preferable that the curable resin layer is located on the optical semiconductor element side relative to the adhesive layer.

[0017] The curable resin layer preferably has thermosetting properties.

[0018] The curable resin layer preferably contains a black colorant.

[0019] The pressure-sensitive adhesive layer is preferably a non-colored pressure-sensitive adhesive layer.

[0020] The adhesive layer is preferably a diffusion function layer.

[0021] It is preferred that the light transmittance of the curable resin layer after curing at a wavelength of 600 nm is 0% to 80%.

[0022] It is preferable that, in a state where the optical semiconductor element is sealed, the distance from the optical semiconductor element to the curable resin layer is 0 μm to 20 μm.

[0023] It is preferable that the thickness of the adhesive layer is 30% or more of the distance from the surface of the substrate to the top of the optical semiconductor element.

[0024] The curable resin layer preferably has a thickness of 70 μm to 150 μm.

[0025] The thickness of the adhesive layer is preferably 30 μm to 100 μm.

[0026] It is preferable that the sheet for optical semiconductor element sealing includes a base portion and the sealing resin layer laminated on the base portion.

[0027] It is preferable that the adhesive layer is located on the side of the base material portion with respect to the curable resin layer.

[0028] The present invention also provides an optical semiconductor device comprising: a substrate; an optical semiconductor element disposed on the substrate; and the optical semiconductor element sealing sheet or a cured product thereof for sealing the optical semiconductor element.

[0029] Effects of the Invention

[0030] The optical semiconductor element encapsulation sheet of the present invention can fully fill the gap between the optical semiconductor element and the substrate when encapsulating the optical semiconductor element, and is less likely to form gaps between multiple optical semiconductor elements. Therefore, when the resin filling the gaps between the multiple optical semiconductor elements is colored, light interference between the optical semiconductor elements can be suppressed, improving the appearance of the optical semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a cross-sectional view of a sheet for encapsulating an optical semiconductor element according to one embodiment of the present invention.

[0032] Figure 2 To express the use of Figure 1 FIG. 1 is a partial cross-sectional view of one embodiment of an optical semiconductor device using a sheet for sealing an optical semiconductor element.

[0033] Label Description

[0034] 1Sheet for sealing optical semiconductor elements

[0035] 2 Sealing resin layer

[0036] 21 Curable resin layer (X)

[0037] 22 adhesive layer

[0038] 3 release liners

[0039] 4 base material

[0040] 41 base film

[0041] 42 functional layers

[0042] 5 substrates

[0043] 6 Optical semiconductor devices

[0044] 7. Curing the sealing layer

[0045] 71 Cured resin layer

[0046] 10 Optical semiconductor devices DETAILED DESCRIPTION

[0047] [Sheet for sealing optical semiconductor elements]

[0048] The optical semiconductor element sealing sheet of the present invention has at least a sealing resin layer comprising a curable resin layer and an adhesive layer. It should be noted that, in this specification, the optical semiconductor element sealing sheet refers to a sheet used to seal one or more optical semiconductor elements arranged on a substrate using a sealing resin layer. In addition, in this specification, "sealing an optical semiconductor element" means burying at least a portion of the optical semiconductor element in the sealing resin layer, or using the above-mentioned sealing resin layer to follow and cover at least a portion of the optical semiconductor element. The above-mentioned sealing resin layer has such flexibility that at least a portion of the optical semiconductor element can be buried therein, or at least a portion of the optical semiconductor element can be followed and covered by the above-mentioned sealing resin layer.

[0049] <Sealing Resin Layer>

[0050] The sealing resin layer at least comprises the curable resin layer and the adhesive layer. The sealing resin layer may comprise other layers in addition to the curable resin layer and the adhesive layer. Each layer constituting the sealing resin layer (curable resin layer and adhesive layer) may be a single layer or a multilayer having the same or different compositions within the sealing resin layer. In the case where the curable resin layer and the adhesive layer comprise multiple layers, the multiple layers may be stacked in contact or in isolation (for example, two curable resin layers may be stacked with an adhesive layer interposed therebetween).

[0051] When sealing an optical semiconductor element, it is preferred that at least one curable resin layer in the sealing resin layer be located on the optical semiconductor element side relative to at least one adhesive layer. It is particularly preferred that the layer in contact with the optical semiconductor element when sealing the optical semiconductor element (i.e., the layer closest to the optical semiconductor element in the sealing resin layer) be a curable resin layer. With this configuration, the curable resin layer flows during sealing of the optical semiconductor element, filling the gap between the optical semiconductor element and the substrate. Furthermore, the adhesive layer can fill any gaps between adjacent optical semiconductor elements that may arise due to the flow of the curable resin layer.

[0052] (Curing resin layer)

[0053] The sealing resin layer includes at least a curable resin layer having a viscosity of 2 kPa·s to 2000 kPa·s at the sealing temperature. In this specification, the curable resin layer may be referred to as "curable resin layer (X)." The sealing resin layer may include a curable resin layer other than the curable resin layer (X).

[0054] As described above, the viscosity of the curable resin layer (X) at the sealing temperature is 2 kPa·s to 2000 kPa·s, preferably 3 kPa·s to 1500 kPa·s, and more preferably 10 kPa·s to 1200 kPa·s. A viscosity of 2 kPa·s or greater prevents excessively low fluidity of the curable resin layer, making it less likely that gaps will form between adjacent optical semiconductor elements. Furthermore, when the viscosity is 2000 kPa·s or less, the curable resin layer (X) flows during sealing of the optical semiconductor element, enabling it to fill the gap between the optical semiconductor element and the substrate. The sealing temperature is preferably 35°C to 120°C, more preferably 40°C to 110°C, even more preferably 60°C to 105°C, and particularly preferably 70°C to 100°C. That is, the viscosity at at least one point between 35°C and 120°C (preferably 40°C to 110°C, more preferably 60°C to 105°C, and even more preferably 70°C to 100°C) is preferably within the above range. The viscosity can be controlled by, for example, the monomer composition and weight average molecular weight of the resin constituting the adhesive composition for forming the adhesive layer, the amount of the polyfunctional monomer and crosslinking agent used (added amount), and the types and contents of other additives.

[0055] Examples of the curable resin layer include thermosetting resin layers and active energy ray-curable resin layers. Examples of the active energy rays include electron beams, ultraviolet rays, α-rays, β-rays, γ-rays, and X-rays. Among these, thermosetting resin layers are preferred because they are easily cured after being bonded to an optical semiconductor element.

[0056] As the resin constituting the curable resin layer, known or commonly used resins may be cited, for example, acrylic resins, urethane acrylate resins, carbamate resins, rubber resins, epoxy resins, epoxy acrylate resins, oxetane resins, silicone resins, silicone acrylic resins, polyester resins, polyether resins (such as polyvinyl ether), polyamide resins, fluorine-containing resins, vinyl acetate / vinyl chloride copolymers, modified polyolefins, etc. The above resins may be used alone or in combination of two or more. Among them, acrylic resins are preferred.

[0057] The acrylic resin is a resin containing structural units derived from acrylic monomers (monomer components having a (meth)acryloyl group or a structure convertible to a (meth)acryloyl group in the molecule) as the structural units of the resin (polymer). These acrylic resins may be used alone or in combination of two or more.

[0058] The acrylic resin is preferably a resin containing the largest mass fraction of structural units derived from (meth)acrylate. It should be noted that in this specification, "(meth)acrylic acid" refers to "acrylic acid" and / or "methacrylic acid" (either or both), and the same applies to other terms.

[0059] From the perspective of preferably having thermosetting properties, the curable resin layer preferably comprises a thermosetting resin. As the thermosetting resin, known or commonly used thermosetting resins can be used, for example, resins having thermosetting functional groups. Among them, as the thermosetting resin, acrylic resins having thermosetting functional groups (acrylic resins containing thermosetting functional groups) are preferred.

[0060] Examples of the thermosetting functional group include epoxy groups such as glycidyl groups, carboxyl groups, hydroxyl groups, isocyanate groups, and aziridine groups. Of these, epoxy groups are preferred, with glycidyl groups being more preferred. Specifically, acrylic resins having thermosetting functional groups are particularly preferred, including glycidyl groups. The thermosetting functional groups may be present in a single species or in two or more species.

[0061] The thermosetting functional group-containing acrylic resin 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 thermosetting functional group-containing monomer include epoxy-containing (meth)acrylates such as glycidyl-containing (meth)acrylates, carboxyl-containing monomers, acid anhydride-containing monomers, and hydroxyl-containing (meth)acrylates.

[0062] Examples of the glycidyl group-containing (meth)acrylate include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate.

[0063] Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the acid anhydride group-containing monomer include maleic anhydride and itaconic anhydride.

[0064] Examples of the hydroxyl-containing (meth)acrylate 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.

[0065] The acrylic monomer containing a thermosetting functional group is preferably an epoxy-containing (meth)acrylate, and more preferably a glycidyl-containing (meth)acrylate. When the acrylic resin contains a structural unit derived from an epoxy-containing (meth)acrylate, the epoxy group functions as a thermosetting functional group. Even in the absence of a curing agent, the epoxy group reacts during thermosetting, thereby curing the curable resin layer. As a result, the curable resin layer exhibits moderate flexibility after thermosetting, resulting in improved sealing properties for optical semiconductor devices.

[0066] The content of the structural units derived from the epoxy-containing (meth)acrylate is preferably 5% to 50% by mass, and more preferably 6% to 45% by mass, relative to the total amount (100% by mass) of all structural units of the acrylic resin in the curable resin layer. When the content is within the above range, the curable resin layer has appropriate flexibility after thermal curing, and the sealing properties of the optical semiconductor element are further improved.

[0067] The thermosetting functional group-containing acrylic resin may contain structural units derived from monomers other than the thermosetting functional group-containing monomer. Examples of such other monomers include (meth)acrylates other than the thermosetting functional group-containing acrylic monomer. Such other monomers may be used alone or in combination of two or more.

[0068] Examples of the other (meth)acrylates include hydrocarbon group-containing (meth)acrylates that may have an alkoxy group. Examples of the hydrocarbon group-containing (meth)acrylates among the hydrocarbon group-containing (meth)acrylates that may have an alkoxy group include (meth)acrylate alkyl esters having a linear or branched aliphatic hydrocarbon group, (meth)acrylates having alicyclic hydrocarbon groups such as cycloalkyl (meth)acrylates, and (meth)acrylates having aromatic hydrocarbon groups such as aryl (meth)acrylates. The hydrocarbon group-containing (meth)acrylates that may have an alkoxy group may be used alone or in combination of two or more.

[0069] Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-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, and eicosyl (meth)acrylate.

[0070] Among the aforementioned alkyl (meth)acrylates, those having a linear or branched aliphatic hydrocarbon group having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 2 to 10, and even more preferably 2 to 8) are preferred. When the number of carbon atoms is within the above range, the flexibility of the thermosetting group-containing acrylic resin during thermosetting is more appropriately achieved, and embedding properties are further improved.

[0071] 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, and cyclooctyl (meth)acrylate; (meth)acrylates having a dicyclic aliphatic hydrocarbon ring, such as isobornyl (meth)acrylate; and (meth)acrylates having three or more aliphatic hydrocarbon rings, such as tetrahydrodicyclopentadienyl (meth)acrylate, tetrahydrodicyclopentadienyloxyethyl (meth)acrylate, tetrahydrotricyclopentadienyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

[0072] Examples of the (meth)acrylate having an aromatic hydrocarbon group include phenyl (meth)acrylate and benzyl (meth)acrylate.

[0073] Examples of the hydrocarbon group-containing (meth)acrylate having an alkoxy group include those obtained by replacing one or more hydrogen atoms in the hydrocarbon group of the above-mentioned hydrocarbon group-containing (meth)acrylate with an alkoxy group, such as 2-methoxymethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, and 2-methoxybutyl (meth)acrylate.

[0074] 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)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of the phosphoric acid group-containing monomers include 2-hydroxyethyl acryloylphosphate. Examples of the nitrogen atom-containing monomers include morpholine group-containing monomers such as (meth)acryloylmorpholine, cyano group-containing monomers such as (meth)acrylonitrile, and amide group-containing monomers such as (meth)acrylamide.

[0075] The thermosetting functional group-containing acrylic resin may include structural units derived from a multifunctional (meth)acrylate copolymerizable with the monomer components constituting the acrylic resin to form a crosslinked structure within its polymer backbone. Examples of the multifunctional (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 multifunctional (meth)acrylates may be used alone or in combination of two or more.

[0076] The aforementioned thermosetting functional group-containing acrylic resin is obtained by polymerizing the various monomer components described above. The polymerization method is not particularly limited, and examples thereof include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization methods using active energy ray irradiation (active energy ray polymerization). The resulting acrylic resin may be any of a random copolymer, a block copolymer, and a graft copolymer.

[0077] The weight-average molecular weight of the epoxy-containing acrylic resin is preferably 2,000 to 400,000, more preferably 30,000 to 300,000, to ensure that the curable resin layer has a certain degree of hardness after curing and to reduce the adhesion between the sides of the optical semiconductor device. When the weight-average molecular weight is within this range, the embedding properties of the optical semiconductor device are further improved. It should be noted that the weight-average molecular weight is the value measured by gel permeation chromatography (GPC) and calculated using polystyrene conversion.

[0078] The content of the epoxy-containing acrylic resin relative to the total amount of resin in the curable resin layer (100% by mass) is preferably 40% by mass or greater (e.g., 40% to 100% by mass), more preferably 50% by mass or greater, and even more preferably 60% by mass or greater. When the content is 40% by mass or greater, the embedding properties of the optical semiconductor element are further improved.

[0079] The curable resin layer 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 when the curable resin layer is heated further promotes the curing of the curable resin layer.

[0080] The component having a second functional group may be the thermosetting functional group-containing acrylic resin having the first functional group, a thermosetting functional group-containing acrylic resin other than the thermosetting functional group-containing acrylic resin having the first functional group, or another component having a second functional group. The component having a second functional group may be used alone or in combination of two or more.

[0081] Examples of combinations of the first functional group and the second functional group include carboxyl and epoxy groups, epoxy and carboxyl groups, carboxyl and aziridine groups, aziridine and carboxyl groups, hydroxyl and isocyanate groups, and isocyanate and hydroxyl groups. The combinations may be one or more.

[0082] In the case of containing the above-mentioned epoxy-containing acrylic resin, the above-mentioned curable resin layer preferably contains a component having a functional group reactive with an epoxy group as the above-mentioned component having a second functional group. Examples of the above-mentioned functional group reactive with an epoxy group include a carboxyl group, an aziridine group, and a hydroxyl group. Among them, a carboxyl group and a hydroxyl group are preferred. As the above-mentioned hydroxyl group, a silanol group is preferred from the viewpoint of high acidity and excellent reactivity with an epoxy group.

[0083] The component having a carboxyl group is preferably the above-mentioned resin, more preferably a carboxyl group-containing acrylic resin. When the carboxyl group-containing acrylic resin is included, the reaction between the epoxy group and the carboxyl group in the epoxy group-containing acrylic resin proceeds more readily even without a curing agent, resulting in improved sealing properties for optical semiconductor devices. Furthermore, the surface resistance to scratching is further improved.

[0084] The carboxyl group-containing acrylic resin preferably comprises a structural unit derived from a carboxyl group-containing monomer, more preferably comprises a structural unit derived from a carboxyl group-containing acrylic monomer. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

[0085] The content of the structural units derived from the carboxyl group-containing acrylic monomer is preferably 1% to 50% by mass, and more preferably 10% to 40% by mass, relative to the total amount (100% by mass) of all structural units of the carboxyl group-containing acrylic resin. When the content is within the above range, the curable resin layer has appropriate flexibility after thermal curing, and the sealing properties of the optical semiconductor element are further improved.

[0086] The carboxyl group-containing acrylic resin may contain structural units derived from monomers other than the carboxyl group-containing monomer. Examples of the other monomers include other (meth)acrylates other than the thermosetting functional group-containing acrylic monomer, the polar group-containing monomer, and the multifunctional (meth)acrylate. The other monomers may be used alone or in combination of two or more.

[0087] Examples of the aforementioned other (meth)acrylates include the aforementioned hydrocarbon group-containing (meth)acrylates that may have an alkoxy group. Among the aforementioned hydrocarbon group-containing (meth)acrylates that may have an alkoxy group, preferred are alkyl (meth)acrylates having a linear or branched aliphatic hydrocarbon group with 1 to 20 carbon atoms (preferably 1 to 14, more preferably 1 to 10, and even more preferably 1 to 8). When the number of carbon atoms is within the aforementioned range, the thermosetting group-containing acrylic resin can be made more flexible and embeddability can be further improved.

[0088] In order to appropriately exhibit basic properties such as adhesion to the above-mentioned optical semiconductor element in the curable resin layer, the proportion of the above-mentioned hydrocarbon group-containing (meth)acrylate that may have an alkoxy group is preferably 50% by mass to 95% by mass, and more preferably 60% by mass to 90% by mass, relative to the total amount (100% by mass) of all structural units of the above-mentioned carboxyl group-containing acrylic resin.

[0089] The weight-average molecular weight of the carboxyl group-containing acrylic resin is preferably 1,000 to 200,000, more preferably 3,000 to 100,000. When the weight-average molecular weight is within this range, the sealing properties of the optical semiconductor element are further improved. The weight-average molecular weight is the value measured by gel permeation chromatography (GPC) and calculated using polystyrene conversion.

[0090] When the carboxyl group-containing acrylic resin is included, the content of the carboxyl group-containing acrylic resin relative to the total amount of resin in the curable resin layer (100% by mass) is preferably 5% to 60% by mass, more preferably 10% to 50% by mass, and even more preferably 25% to 45% by mass. When the content is within the above range, the curable resin layer exhibits further improved thermosetting properties and surface scratch resistance.

[0091] The curable resin layer may contain a colorant. For example, when the curable resin layer contains a colorant, it can prevent light reflection caused by metal wiring, etc., provided on the substrate in the image display device. In particular, when the curable resin layer (X), such as the curable resin layer located closer to the optical semiconductor element than the adhesive layer, is a colored layer containing a colorant, when the optical semiconductor element is sealed, the gap between the optical semiconductor element and the substrate is filled while a thin layer remains on the upper surface and side surfaces of the optical semiconductor element. This can further suppress light interference between the optical semiconductor elements, thereby improving the appearance of the optical semiconductor device.

[0092] The colorant can be either a dye or a pigment as long as it is soluble or dispersed in the curable resin layer. Dyes are preferred because they can achieve low haze even when added in small amounts and are easily evenly distributed without sedimentation like pigments. Pigments are also preferred because they have high color development properties even when added in small amounts. When a pigment is used as a colorant, a pigment with low or no electrical conductivity is preferred. One or more of the colorants may be used.

[0093] The colorant is preferably a black colorant. Known or commonly used colorants (pigments, dyes, etc.) for imparting black color can be used as the black colorant. Examples thereof 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 colorants, and zirconium nitride. Furthermore, a colorant that functions as a black colorant by combining colorants imparting colors other than black can be used.

[0094] When the curable resin layer is an active energy ray-curable resin layer, the colorant preferably absorbs visible light and has a transmittance to light of a wavelength at which the active energy ray-curable resin layer can be cured.

[0095] From the viewpoint that image display device is given suitable anti-reflection ability, relative to the total amount (100 mass %) of curable resin layer, the containing ratio of the colorant in the above-mentioned curable resin layer is preferably more than the 0.01 mass %, more preferably more than the 0.02 mass %.In addition, the containing ratio of above-mentioned colorant is, for example, below the 5 mass %, preferably below the 1 mass %, more preferably below the 0.5 mass %.Above-mentioned containing ratio can be suitably set by the kind of colorant, the tone and the transmittance of image display device.Colorant can be used as the solution or the dispersion liquid that are dissolved or are dispersed in suitable solvent and add in composition.

[0096] Above-mentioned curable resin layer can comprise other components except above-mentioned each composition in the scope of not damaging effect of the present invention.As above-mentioned other components, can enumerate: coupling agent such as thermoplastic resin, silane coupling agent, crosslinking accelerator, tackifying resin (rosin derivative, polyterpene resin, petroleum resin, oil-soluble phenolic etc.), oligomer, anti-aging agent, filler (organic filler, inorganic particle etc.), light diffusion property microparticle, antioxidant, plasticizer, softener, surfactant, antistatic agent, surface lubricant, leveling agent, light stabilizer, ultraviolet absorber, polymerization inhibitor, granular object, foil-shaped object etc.Above-mentioned other components can only use one respectively, also can use two or more.

[0097] The content of the resin in the curable resin layer is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more relative to the total amount of the curable resin layer (100% by mass). The content is preferably 99.99% by mass or less, more preferably 99% by mass or less, and even more preferably 95% by mass or less. Furthermore, the content of the acrylic resin is preferably within the above range, the content of the thermosetting resin is preferably within the above range, and the content of the thermosetting functional group-containing acrylic resin is preferably within the above range.

[0098] The light transmittance of the curable resin layer at a wavelength of 600 nm after curing is not particularly limited. However, from the perspective of further improving the function of preventing reflection from metal wiring and the like in the optical semiconductor device and enhancing contrast, it is preferably 80% or less, more preferably 60% or less, even more preferably 40% or less, and particularly preferably 30% or less. Furthermore, from the perspective of ensuring the brightness of the optical semiconductor device, the light transmittance is preferably 0.5% or more, more preferably 1% or more, even more preferably 1.5% or more, particularly preferably 2% or more, and may be 2.5% or more or 3% or more.

[0099] The thickness of the curable resin layer (X) is preferably 50 μm to 150 μm, more preferably 60 μm to 130 μm, and even more preferably 70 μm to 120 μm. When the thickness is 50 μm or greater, more curable resin layer remains between the optical semiconductor elements during sealing, and gaps are less likely to form between the optical semiconductor elements. When the thickness is 150 μm or less, the brightness of light emitted by the optical semiconductor elements is further increased.

[0100] The thickness of the curable resin layer (X) is preferably at least 60% of the distance from the surface of the substrate to the apex of the optical semiconductor element, and more preferably at least 70%. When the thickness is at least 60%, more curable resin layer remains between the optical semiconductor elements during sealing, and gaps are less likely to form between the optical semiconductor elements. The thickness is, for example, no more than 130% of the distance from the surface of the substrate to the apex of the optical semiconductor element, preferably no more than 120%, and more preferably no more than 110%. When the thickness is no more than 130%, the brightness of light emitted by the optical semiconductor element is further increased.

[0101] (Adhesive layer)

[0102] In this manual, " adhesive layer " refers to the layer with following property: by means of pressure-sensitive (such as tiny pressure) from the outside, two faces adhere based on the cohesive force based on chemical structure that composition has, and can be peeled off as needed.Above-mentioned adhesive layer is preferably the resin layer made of resin.As the resin constituting above-mentioned adhesive layer, known or customary resin can be enumerated, for example, acrylic resin, urethane acrylate resin, carbamate resin, rubber resin, epoxy resin, epoxy acrylate resin, oxetane resin, silicone resin, silicone acrylic resin, polyester resin, polyether resin (polyvinyl ether etc.), polyamide resin, fluorine-containing type resin, vinyl acetate / vinyl chloride copolymer, modified polyolefin etc. can be enumerated.Above-mentioned resin can only use one kind, also can use two or more.

[0103] Furthermore, as the resin, a known or customary pressure-sensitive adhesive can be used. Examples of the adhesive include acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, and mixtures thereof), polysiloxane adhesives, polyester adhesives, urethane adhesives, polyether adhesives, polyamide adhesives, and fluorine-containing adhesives. These adhesives may be used alone or in combination of two or more.

[0104] The acrylic resin is a polymer containing a structural unit derived from an acrylic monomer as a structural unit of the polymer. The acrylic resin may be used alone or in combination of two or more.

[0105] Examples of the (meth)acrylates include hydrocarbon group-containing (meth)acrylates. Examples of the hydrocarbon group-containing (meth)acrylates include alkyl (meth)acrylates having a linear or branched aliphatic hydrocarbon group, (meth)acrylates having alicyclic hydrocarbon groups such as cycloalkyl (meth)acrylates, and (meth)acrylates having aromatic hydrocarbon groups such as aryl (meth)acrylates. These hydrocarbon group-containing (meth)acrylates may be used alone or in combination of two or more.

[0106] Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-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, and eicosyl (meth)acrylate.

[0107] Among the aforementioned alkyl (meth)acrylates, those having a linear or branched aliphatic hydrocarbon group having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 2 to 10) are preferred. When the number of carbon atoms is within the aforementioned range, the glass transition temperature of the acrylic resin can be easily adjusted, making it easier to achieve more appropriate adhesive properties in the adhesive layer.

[0108] 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, and cyclooctyl (meth)acrylate; (meth)acrylates having a dicyclic aliphatic hydrocarbon ring, such as isobornyl (meth)acrylate; and (meth)acrylates having three or more aliphatic hydrocarbon rings, such as tetrahydrodicyclopentadienyl (meth)acrylate, tetrahydrodicyclopentadienyloxyethyl (meth)acrylate, tetrahydrotricyclopentadienyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

[0109] Examples of the (meth)acrylate having an aromatic hydrocarbon group include phenyl (meth)acrylate and benzyl (meth)acrylate.

[0110] The hydrocarbon group-containing (meth)acrylate is preferably an alkyl (meth)acrylate having a linear or branched aliphatic hydrocarbon group, and more preferably a (meth)acrylate having an alicyclic hydrocarbon group. In this case, the adhesiveness with the adhesive layer is well balanced, and the adhesive has excellent conformability to the unevenness of the adherend.

[0111] In order to properly exhibit the basic properties of the hydrocarbon-group-containing (meth)acrylate in the adhesive layer, such as adhesiveness and adhesion to an adherend, the proportion of the hydrocarbon-group-containing (meth)acrylate in all monomer components constituting the acrylic resin is preferably 40% by mass or greater, more preferably 50% by mass or greater, and even more preferably 60% by mass or greater, relative to the total amount of all monomer components (100% by mass). Furthermore, from the perspective of copolymerization with other monomer components and achieving the effects of these other monomer components, the above proportion is preferably 95% by mass or less, more preferably 80% by mass or less.

[0112] The proportion of the (meth)acrylate having a linear or branched aliphatic hydrocarbon group in all monomer components constituting the acrylic resin is preferably 30% by mass or greater, and more preferably 40% by mass or greater, relative to the total amount (100% by mass) of all monomer components. Furthermore, the proportion is preferably 90% by mass or less, and more preferably 70% by mass or less.

[0113] The proportion of the (meth)acrylate having an alicyclic hydrocarbon group in all monomer components constituting the acrylic resin is preferably 1% by mass or greater, and more preferably 5% by mass or greater, relative to the total amount (100% by mass) of all monomer components. Furthermore, the proportion is preferably 30% by mass or less, and more preferably 20% by mass or less.

[0114] To introduce the third functional group described below and to improve cohesion, heat resistance, etc., the acrylic resin may contain structural units derived from other monomer components copolymerizable with the hydrocarbon group-containing (meth)acrylate. Examples of these other monomer components include polar group-containing monomers such as carboxyl group-containing monomers, acid anhydride monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and nitrogen atom-containing monomers. These other monomer components may be used singly or in combination.

[0115] Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the acid anhydride monomer include maleic anhydride and itaconic anhydride.

[0116] Examples of the hydroxyl group-containing monomer 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.

[0117] Examples of the glycidyl group-containing monomer include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate.

[0118] Examples of the sulfonic acid group-containing monomer include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid.

[0119] Examples of the phosphoric acid group-containing monomer include 2-hydroxyethyl acryloyl phosphate.

[0120] Examples of the nitrogen atom-containing monomer include morpholine group-containing monomers such as (meth)acryloylmorpholine, cyano group-containing monomers such as (meth)acrylonitrile, and amide group-containing monomers such as (meth)acrylamide.

[0121] The polar group-containing monomer constituting the acrylic resin preferably includes a hydroxyl group-containing monomer. Using a hydroxyl group-containing monomer facilitates the introduction of the tertiary functional group described below. Furthermore, the acrylic resin and the adhesive layer exhibit excellent water resistance, are less susceptible to fogging, and exhibit excellent whitening resistance even when used in high-humidity environments.

[0122] As the hydroxyl group-containing monomer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.

[0123] In order to appropriately exhibit the basic properties of the hydrocarbon-group-containing (meth)acrylate in the adhesive layer, such as adhesiveness and adhesion to an adherend, the proportion of the polar group-containing monomer in the total monomer components (100% by mass) constituting the acrylic resin is preferably 5% to 50% by mass, and more preferably 10% to 40% by mass. In particular, from the perspective of achieving superior water resistance in the adhesive layer, the proportion of the hydroxyl-containing monomer is preferably within the above range.

[0124] As the above-mentioned other monomer components, vinyl monomers such as caprolactone adducts of (meth)acrylic acid, vinyl acetate, vinyl propionate, styrene, α-methylstyrene, etc.; diol acrylate monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, etc.; acrylate monomers such as tetrahydrofurfuryl (meth)acrylate, fluorine-containing (meth)acrylate, silicon-containing (meth)acrylate, alkoxy-substituted hydrocarbon group-containing (meth)acrylate (2-methoxyethyl (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, etc.) can also be contained.

[0125] The ratio of the other monomer components in the total monomer components (100% by mass) constituting the acrylic resin is, for example, about 3% to 50% by mass, 5% to 40% by mass, or 10% to 30% by mass.

[0126] The acrylic resin may contain structural units derived from a multifunctional (meth)acrylate copolymerizable with the monomer components constituting the acrylic resin to form a crosslinked structure within its polymer backbone. Examples of the multifunctional (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 multifunctional (meth)acrylates may be used alone or in combination of two or more.

[0127] In order to properly exhibit the basic properties such as adhesiveness and adhesion to the adherend brought about by the above-mentioned hydrocarbon group-containing (meth)acrylate in the above-mentioned adhesive layer, the proportion of the above-mentioned multifunctional (meth)acrylate in the total monomer components (100% by mass) constituting the above-mentioned acrylic resin is preferably 40% by mass or less, and more preferably 30% by mass or less.

[0128] The adhesive layer may be an adhesive layer having a property of being cured by irradiation with active energy rays (active energy ray-curable adhesive layer), an adhesive layer having a thermosetting property (thermosetting adhesive layer), or an adhesive layer having a non-curing property (non-curing adhesive layer).

[0129] In the case where the above-mentioned adhesive layer is an active energy ray-curable adhesive layer, examples of the above-mentioned adhesive layer include a layer containing an active energy ray-polymerizable monomer component or oligomer component containing a base polymer and functional groups such as active energy ray-polymerizable carbon-carbon double bonds; a layer containing a polymer having active energy ray-polymerizable functional groups (especially an acrylic resin) as a base polymer, etc.

[0130] Examples of the active energy ray polymerizable functional groups include active energy ray free radical polymerizable groups such as groups containing carbon-carbon unsaturated bonds, such as ethylenically unsaturated groups, and active energy ray cation polymerizable groups. Examples of the groups containing carbon-carbon unsaturated bonds include vinyl, propenyl, isopropenyl, acryloyl, and methacryloyl groups. Examples of the active energy ray cation polymerizable groups include epoxy, oxetane, and oxolane groups. Among these, groups containing carbon-carbon unsaturated bonds are preferred, and acryloyl and methacryloyl groups are more preferred. The active energy ray polymerizable functional groups may be of one type or of two or more types. The position of the active energy ray polymerizable functional groups may be any one of the polymer side chains, the polymer main chain, and the polymer main chain ends.

[0131] The polymer having an active energy ray polymerizable functional group can be produced, for example, by reacting a polymer having a reactive functional group (third functional group) with a compound having a functional group (fourth functional group) capable of reacting with the third functional group to form a bond, while maintaining the active energy ray polymerizable nature of the active energy ray polymerizable functional group, thereby bonding them. Therefore, the polymer having an active energy ray polymerizable functional group preferably includes a structural portion derived from the polymer having the third functional group and a structural portion derived from the compound having the fourth functional group and the active energy ray polymerizable functional group.

[0132] Examples of combinations of the third functional group and the fourth functional group include a carboxyl group and an epoxy group, an epoxy group and a carboxyl group, a carboxyl group and an aziridine group, an aziridine group and a carboxyl group, a hydroxyl group and an isocyanate group, and an isocyanate group and a hydroxyl group. Among these, from the perspective of ease of reaction tracking, combinations of a hydroxyl group and an isocyanate group, and combinations of an isocyanate group and a hydroxyl group are preferred. These combinations may be one or more.

[0133] Examples of the compound having the active energy polymerizable functional group and the isocyanate group include methacryloyl isocyanate, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate (MOI), and m-isopropenyl-α,α-dimethylbenzyl isocyanate. These compounds may be used alone or in combination of two or more.

[0134] From the perspective of enabling further curing of the active energy ray-curable adhesive layer, the content of the structural unit derived from the compound having the fourth functional group and the active energy ray-polymerizable functional group in the acrylic resin having the active energy ray-polymerizable functional group is preferably 0.5 mol or more, more preferably 1 mol or more, further preferably 3 mol or more, and particularly preferably 10 mol or more, based on 100 mol of the total amount of the structural unit derived from the acrylic resin having the third functional group. For example, the above content is 100 mol or less.

[0135] From the perspective of further promoting the curing of the active energy ray-curable adhesive layer, the molar ratio of the fourth functional group to the third functional group in the acrylic resin having an active energy ray-polymerizable functional group [fourth functional group / third functional group] is preferably 0.01 or greater, more preferably 0.05 or greater, even more preferably 0.2 or greater, and particularly preferably 0.4 or greater. Furthermore, from the perspective of further reducing low-molecular-weight substances in the active energy ray-curable adhesive layer, the molar ratio is preferably less than 1.0, and more preferably 0.9 or less.

[0136] The acrylic resin is obtained by polymerizing the various monomer components described above. The polymerization method is not particularly limited, and examples thereof include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization methods utilizing active energy ray irradiation (active energy ray polymerization). The resulting acrylic resin may be any of a random copolymer, a block copolymer, and a graft copolymer.

[0137] The above-mentioned acrylic resin having an active energy ray polymerizable functional group can be produced, for example, by the following method: a raw material monomer containing a monomer component having a third functional group is polymerized (copolymerized) to obtain an acrylic resin having a third functional group, and then the above-mentioned compound having a fourth functional group and an active energy ray polymerizable functional group is subjected to a condensation reaction or an addition reaction on the acrylic resin while maintaining the active energy ray polymerizability of the active energy ray polymerizable functional group.

[0138] During the polymerization of the monomer components, various conventional solvents can be used. Examples of such solvents include organic solvents such as esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. These solvents may be used alone or in combination of two or more.

[0139] The polymerization initiator, chain transfer agent, emulsifier, etc. used in the free radical polymerization of the monomer components are not particularly limited and can be appropriately selected for use. It should be noted that the weight-average molecular weight of the acrylic resin can be controlled by the amount of the polymerization initiator and chain transfer agent used and the reaction conditions, and their amounts can be appropriately adjusted according to their types.

[0140] As the polymerization initiator used for polymerization of the monomer components, a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), etc. can be used depending on the type of polymerization reaction.

[0141] The thermal polymerization initiator is not particularly limited, and examples thereof include azo-based polymerization initiators, peroxide-based polymerization initiators, and redox-based polymerization initiators. The amount of the thermal polymerization initiator used is preferably 1 part by mass or less, more preferably 0.005 to 1 part by mass, and even more preferably 0.02 to 0.5 parts by mass, relative to 100 parts by mass of all monomer components constituting the acrylic resin having a third functional group.

[0142] Examples of the photopolymerization initiator include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and titanocene-based photopolymerization initiators. Among them, acetophenone-based photopolymerization initiators are preferred.

[0143] Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, 4-(tert-butyl)dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, and methoxyacetophenone.

[0144] The amount of the photopolymerization initiator used is preferably 0.005 to 1 part by mass, more preferably 0.01 to 0.7 parts by mass, and even more preferably 0.18 to 0.5 parts by mass, relative to 100 parts by mass of the total amount of all monomer components constituting the acrylic resin. When the amount used is 0.005 parts by mass or greater (particularly 0.18 parts by mass or greater), the molecular weight of the acrylic resin can be easily controlled to be low, and the resin layer tends to have better conformability to uneven surfaces.

[0145] The reaction of the acrylic resin having a third functional group with the compound having a fourth functional group and an active energy ray-polymerizable functional group can be carried out, for example, in a solvent with stirring in the presence of a catalyst. Examples of the solvent include the solvents listed above. The catalyst can be appropriately selected depending on the combination of the third and fourth functional groups. The reaction temperature in the reaction is, for example, 5°C to 100°C, and the reaction time is, for example, 1 hour to 36 hours.

[0146] The acrylic resin may have a structural portion derived from a crosslinking agent. For example, the acrylic resin can be crosslinked, thereby further reducing low-molecular-weight substances in the adhesive layer. In addition, the weight-average molecular weight of the acrylic resin can be increased. It should be noted that, when the acrylic resin has active energy ray-polymerizable functional groups, the crosslinking agent crosslinks functional groups other than the active energy ray-polymerizable functional groups (for example, third functional groups with each other, fourth functional groups with each other, or third functional groups with fourth functional groups). The crosslinking agent may be used alone or in combination of two or more.

[0147] Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, Oxazoline crosslinking agents, aziridine crosslinking agents, amine crosslinking agents, silicone crosslinking agents, silane crosslinking agents, etc. As the crosslinking agent, from the viewpoint of excellent adhesion to optical semiconductor elements and the viewpoint of less impurity ions, isocyanate crosslinking agents and epoxy crosslinking agents are preferred, and isocyanate crosslinking agents are more preferred.

[0148] Examples of the isocyanate crosslinking agent (polyfunctional isocyanate compound) include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated xylene diisocyanate; and aromatic polyisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate. Examples of the isocyanate crosslinking agent include trimethylolpropane / toluene diisocyanate adducts, trimethylolpropane / hexamethylene diisocyanate adducts, and trimethylolpropane / xylylene diisocyanate adducts.

[0149] The content of the structural portion derived from the cross-linking agent is not particularly limited, but is preferably 5 parts by mass or less, more preferably 0.001 to 5 parts by mass, and even more preferably 0.01 to 3 parts by mass, relative to 100 parts by mass of the total amount of the acrylic resin excluding the structural portion derived from the cross-linking agent.

[0150] The adhesive layer is preferably a non-colored adhesive layer. The non-colored adhesive layer is a layer different from the colored layer and is not intended to prevent light reflection from metal wiring, etc. The non-colored adhesive layer may be colorless or slightly colored. Furthermore, the non-colored adhesive layer may be, for example, a light-diffusing layer or a non-light-diffusing layer. The non-colored adhesive layer may be transparent or opaque.

[0151] The content of the colorant in the above-mentioned non-coloring adhesive layer is preferably less than 0.2% by mass, more preferably less than 0.1% by mass, and further preferably less than 0.05% by mass, relative to the total amount of the non-coloring adhesive layer (100% by mass), and can be less than 0.01% by mass or less than 0.005% by mass.

[0152] The total light transmittance of the non-colored adhesive layer is not particularly limited. However, from the perspective of ensuring brightness, it is preferably 40% or higher, more preferably 60% or higher, even more preferably 70% or higher, and particularly preferably 80% or higher. The upper limit of the total light transmittance of the non-colored adhesive layer is not particularly limited and may be less than 100%, 99.9% or lower, or 99% or lower.

[0153] The total light transmittance of the non-colored adhesive layer is a value for a single layer and can be measured using the method specified in JIS K7136 and JIS K7361-1. It can be controlled by the type and thickness of the non-colored adhesive layer.

[0154] The diffusion function layer is a layer for the purpose of diffusing light. When the adhesive layer is the diffusion function layer, light emitted from the optical semiconductor element is diffused in the diffusion function layer. For example, light emitted from the side of the optical semiconductor element is emitted toward the front of the image display device, thereby improving the front brightness of the image display device. The diffusion function layer is not limited, but preferably contains light-diffusing particles. In other words, the diffusion function layer preferably contains light-diffusing particles dispersed in the adhesive layer. The light-diffusing particles may be used alone or in combination of two or more.

[0155] The light diffusing particles have an appropriate refractive index difference with the resin constituting the diffusion function layer, thereby imparting diffusion properties to the diffusion function layer. Examples of the light diffusing particles include inorganic particles and polymer particles. Examples of the material of the inorganic particles include silicon dioxide, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and metal oxides. Examples of the material of the polymer particles include silicone resins, acrylic resins (e.g., polymethacrylate resins such as polymethyl methacrylate), polystyrene resins, polyurethane resins, melamine resins, polyethylene resins, and epoxy resins.

[0156] The polymer microparticles are preferably microparticles composed of a silicone resin. Furthermore, the inorganic microparticles are preferably microparticles composed of a metal oxide. Preferred metal oxides include titanium oxide and barium titanate, with titanium oxide being more preferred. This configuration further improves the light diffusivity of the diffusion function layer and reduces uneven brightness.

[0157] The shape of the light diffusing fine particles is not particularly limited, and may be, for example, a true spherical shape, a flat shape, or an irregular shape.

[0158] From the perspective of imparting appropriate light diffusion properties, the average particle size of the light diffusing fine particles is preferably 0.1 μm or greater, more preferably 0.15 μm or greater, even more preferably 0.2 μm or greater, and particularly preferably 0.25 μm or greater. Furthermore, from the perspective of preventing excessively high haze values and displaying high-definition images, the average particle size of the light diffusing fine particles is preferably 12 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less. The average particle size can be measured, for example, using a Coulter counter.

[0159] The refractive index of the light diffusing fine particles is preferably 1.2 to 5, more preferably 1.25 to 4.5, further preferably 1.3 to 4, and particularly preferably 1.35 to 3.

[0160] From the perspective of more effectively reducing uneven brightness in an image display device, the absolute value of the refractive index difference between the light diffusing fine particles and the resin constituting the diffusion function layer (the resin layer excluding the light diffusing fine particles in the diffusion function layer) is preferably 0.001 or greater, more preferably 0.01 or greater, further preferably 0.02 or greater, particularly preferably 0.03 or greater, and may be 0.04 or greater or 0.05 or greater. Furthermore, from the perspective of preventing excessively high haze values and displaying high-definition images, the absolute value of the refractive index difference between the light diffusing fine particles and the resin is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less.

[0161] From the perspective of imparting appropriate light diffusion properties to the optical semiconductor element encapsulating sheet, the content of the light diffusing fine particles in the diffusion functional layer is preferably 0.01 parts by mass or greater, more preferably 0.05 parts by mass or greater, even more preferably 0.1 parts by mass or greater, and particularly preferably 0.15 parts by mass or greater, relative to 100 parts by mass of the resin constituting the diffusion functional layer. Furthermore, from the perspective of preventing excessively high haze values and achieving high-definition images, the content of the light diffusing fine particles is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, relative to 100 parts by mass of the resin constituting the diffusion functional layer.

[0162] The haze value (thickness 50 μm) of the diffusion function layer is not particularly limited. From the perspective of effectively reducing brightness unevenness, it is preferably 30% or more, more preferably 40% or more, further preferably 50% or more, particularly preferably 60% or more, and can be 70% or more, 80% or more, 90% or more, 95% or more, or 97% or more. In addition, a haze value of around 99.9% is preferred due to its excellent effect in improving brightness unevenness. It should be noted that the upper limit of the haze value of the diffusion function layer is not particularly limited, i.e., it can be 100%. The haze value can be any value before and after curing, preferably the value after curing.

[0163] The total light transmittance of the diffusion function layer is not particularly limited. From the perspective of ensuring brightness, it is preferably 40% or higher, more preferably 60% or higher, even more preferably 70% or higher, and particularly preferably 80% or higher. The upper limit of the total light transmittance of the diffusion function layer is not particularly limited and may be less than 100%, or may be 99.9% or lower, or 99% or lower.

[0164] The haze value and total light transmittance of the above-mentioned diffusion function layer are the values of a single layer, which can be measured using the methods specified in JIS K7136 and JIS K7361-1, and can be controlled by the type and thickness of the diffusion function layer, the type and amount of the light diffusing fine particles, etc.

[0165] The haze value (thickness 50 μm) of the non-diffusing functional layer is not particularly limited. From the perspective of achieving excellent brightness, it is preferably less than 30%, more preferably 10% or less, further preferably 5% or less, particularly preferably 1% or less, and may be 0.5% or less. It should be noted that there is no particular lower limit for the haze value of the non-diffusing functional layer.

[0166] The total light transmittance of the non-diffusing functional layer is not particularly limited. From the perspective of ensuring brightness, it is preferably 60% or higher, more preferably 70% or higher, further preferably 80% or higher, and particularly preferably 90% or higher. The upper limit of the total light transmittance of the non-diffusing functional layer is not particularly limited and may be less than 100%, or may be 99.9% or lower, or 99% or lower.

[0167] The haze value and total light transmittance of the non-diffusing functional layer are values for a single layer and can be measured using the methods specified in JIS K7136 and JIS K7361-1. They can be controlled by the type and thickness of the non-diffusing functional layer.

[0168] From the perspective of achieving excellent brightness of the image display device, the content of the colorant and / or light diffusing fine particles in the non-diffusing functional layer is preferably less than 0.01 parts by mass, more preferably less than 0.005 parts by mass, relative to 100 parts by mass of the resin constituting the non-diffusing functional layer.

[0169] The light transmittance of the non-colored adhesive layer after curing (50 μm thickness) at a wavelength of 600 nm is not particularly limited, but is preferably greater than 80%, more preferably 85% or greater, and even more preferably 90% or greater from the perspective of further improving the brightness of the optical semiconductor device. The light transmittance is 100% or less.

[0170] The gel fraction (ratio of insoluble components) of the adhesive layer is preferably 50% or more, more preferably 60% or more. The gel fraction is preferably 98% or less, more preferably 95% or less. When the gel fraction is 50% or more, the fluidity during sealing will not become too low, and the spaces between the optical semiconductor elements can be filled more fully. When the gel fraction is 98% or less, moderate softness can be obtained, and the sealing of the optical semiconductor elements is more excellent. The gel fraction can be controlled, for example, by the monomer composition, weight-average molecular weight, multifunctional monomer, amount of cross-linking agent used (added amount), type and content of other additives, etc. of the resin constituting the adhesive composition for forming the adhesive layer.

[0171] The thickness of the adhesive layer is preferably 30 μm to 100 μm, more preferably 35 μm to 90 μm, and further preferably 40 μm to 80 μm. When the thickness is 30 μm or more, the filling property between the optical semiconductor elements is better. When the thickness is 100 μm or less, the light extraction efficiency is excellent and the brightness of the semiconductor device is better. The thickness of the adhesive layer is the thickness of the adhesive layer located on the side opposite to the optical semiconductor element during sealing relative to the curable resin layer (X), and is the total thickness in the case of a plurality of continuous adhesive layers.

[0172] The thickness of the adhesive layer is preferably at least 30% of the distance from the surface of the substrate to the apex of the optical semiconductor element, more preferably at least 35%, and even more preferably at least 40%. When the thickness is at least 30%, the filling properties between the optical semiconductor elements are further improved. The thickness of the adhesive layer refers to the thickness of the adhesive layer located on the side opposite to the optical semiconductor element during sealing relative to the curable resin layer (X). In the case of a plurality of continuous adhesive layers, this is the total thickness.

[0173] In the sealing resin layer, the curable resin layer (X) is preferably located on the optical semiconductor element side relative to the adhesive layer, and more preferably, no adhesive layer is provided on the optical semiconductor element side of the curable resin layer (X). With such a structure, the space between the optical semiconductor element and the substrate can be filled more fully. In addition, in the sealing resin layer, a curable resin layer (another curable resin layer) other than the curable resin layer (X) may be provided on the optical semiconductor element side of the curable resin layer (X), between the curable resin layer (X) and the adhesive layer, or on the side of the adhesive layer opposite to the curable resin layer (X).

[0174] Examples of the laminated structure of the sealing resin layer include [curable resin layer (X) / adhesive layer (diffusion function layer)], [curable resin layer (X) / adhesive layer (non-diffusion function layer)], and [curable resin layer (X) / adhesive layer (diffusion function layer) / adhesive layer (non-diffusion function layer)] (these are in this order from the optical semiconductor element side). Furthermore, in the above-mentioned laminated structure, a curable resin layer may be provided on the optical semiconductor element side of the curable resin layer (X), between the curable resin layer (X) and the adhesive layer, between the adhesive layers, or on the side of the adhesive layer opposite to the optical semiconductor element.

[0175] (Base material part)

[0176] In the optical semiconductor element sealing sheet of the present invention, the sealing resin layer may be provided on at least one side of the substrate portion. That is, the semiconductor element sealing sheet may include a substrate portion and the sealing resin layer provided on at least one side of the substrate portion. In the case where the optical semiconductor element sealing sheet of the present invention has the substrate portion, the side opposite to the side in contact with the optical semiconductor element of the sealing resin layer becomes the side in contact with the substrate portion. In this case, the adhesive layer is located on the substrate portion side relative to the curable resin layer (X). When the substrate portion is provided on the side opposite to the optical semiconductor element side of the sealing resin layer in the optical semiconductor element sealing sheet, the surface of the sealing resin layer can be made flat, thereby not easily causing diffuse reflection of light, and the aesthetics of the optical semiconductor device is improved in both the case of extinguishing and emitting light. In addition, by forming the anti-glare layer and the anti-reflection layer described later on the substrate portion, the optical semiconductor device can be given anti-glare and anti-reflection properties. In addition, in the optical semiconductor element sealing sheet, the substrate portion becomes the support body of the sealing resin layer, and by having the substrate portion, the optical semiconductor element sealing sheet has excellent handleability. It should be noted that the base material portion does not necessarily need to be provided.

[0177] The substrate portion may be a single layer or may be a plurality of layers of the same or different compositions, thicknesses, etc. In the case of a plurality of layers, the layers may be bonded together via other layers such as adhesive layers. It should be noted that the substrate layer used in the substrate portion is the portion that is bonded to the adherend together with the sealing resin layer. The release liner that is peeled off when the optical semiconductor element sealing sheet is used (during bonding) and the surface protection film that merely protects the surface of the substrate portion are not included in the "substrate portion".

[0178] Examples of the substrate layer constituting the substrate portion include glass, plastic substrates (particularly plastic films), etc. Examples of the resin constituting the plastic substrate include 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, ionomers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylate (random, alternating) copolymers, ethylene-vinyl acetate copolymers (EVA), ethylene-propylene copolymers, cyclic olefin polymers, ethylene-butene copolymers, and ethylene-hexene copolymers. Polyolefin resins such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT); polycarbonate; polyimide resins; polyetheretherketone; polyetherimide; polyamides such as aramid and wholly aromatic polyamide; polyphenylene sulfide; fluorine-containing resins; 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. The substrate layer may be various optical films such as an antireflection (AR) film, a polarizer, and a phase difference plate.

[0179] The thickness of the plastic film is preferably 20 μm to 300 μm, more preferably 40 μm to 250 μm. When the thickness is 20 μm or greater, the support and handling properties of the optical semiconductor element encapsulating sheet are further improved. When the thickness is 300 μm or less, the optical semiconductor element encapsulating sheet can be further thinned.

[0180] To improve adhesion and retention with the sealing resin layer, the surface of the substrate portion on the side where the sealing resin layer is to be disposed may be subjected to physical treatments such as corona discharge treatment, plasma treatment, sandblasting, ozone exposure, flame exposure, high voltage electric shock exposure, or ionizing active energy ray treatment; chemical treatments such as chromic acid treatment; and surface treatments such as adhesion-enhancing treatment using a coating agent (primer). The surface treatment for improving adhesion is preferably applied to the entire surface of the substrate portion on the side facing the sealing resin layer.

[0181] From the perspective of functioning as a support and excellent surface scratch resistance, the thickness of the substrate is preferably 5 μm or more, more preferably 10 μm or more. From the perspective of better transparency, the thickness of the substrate is preferably 300 μm or less, more preferably 250 μm or less.

[0182] <Optical semiconductor element sealing sheet>

[0183] The above-mentioned optical semiconductor element sealing sheet may have a layer with anti-glare and / or anti-reflective properties. By having such a structure, it is possible to suppress the gloss and reflection of light when sealing the optical semiconductor element, so that the appearance is better. As the above-mentioned layer with anti-glare properties, an anti-glare treatment layer can be listed. As the above-mentioned layer with anti-reflective properties, an anti-reflective treatment layer can be listed. The anti-glare treatment and the anti-reflective treatment can be implemented by known or customary methods, respectively. The above-mentioned layer with anti-glare properties and the above-mentioned layer with anti-reflective properties may be the same layer or different layers. The above-mentioned layer with anti-glare and / or anti-reflective properties may have only one layer or may have two or more layers. The above-mentioned layer with anti-glare and / or anti-reflective properties is preferably provided on the surface (preferably the surface) on the opposite side of the side in contact with the optical semiconductor element of the above-mentioned optical semiconductor element sealing sheet relative to the above-mentioned sealing resin layer.

[0184] The haze value of the optical semiconductor element sealing sheet is not particularly limited. From the perspective of suppressing uneven brightness and achieving better design properties, it is preferably 0.5% or more, more preferably 1% or more, and even more preferably 3% or more. It should be noted that the upper limit of the haze value is not particularly limited and may be 100%, 80%, 60%, or 40%. The haze value may be any value before and after curing, preferably after curing.

[0185] The total light transmittance of the optical semiconductor element encapsulation sheet is not particularly limited. However, from the perspective of further improving the function of preventing reflection from metal wiring and the like and enhancing contrast, it is preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less. Furthermore, from the perspective of ensuring brightness, the total light transmittance is preferably 0.5% or more.

[0186] The haze value and total light transmittance can be measured using the methods specified in JIS K7136 and JIS K7361-1, respectively, and can be controlled by adjusting the lamination order, type, thickness, etc. of each layer constituting the sealing resin layer and the base material.

[0187] When the optical semiconductor element sealing sheet is used to seal an optical semiconductor element, the distance from the optical semiconductor element to the curable resin layer (X) is preferably 0 μm to 20 μm, more preferably 0 μm to 10 μm. When the distance is within this range, the image display device exhibits better antireflection properties and brightness.

[0188] From the perspective of improving the function of preventing reflection from metal wiring, etc., enhancing contrast, and more effectively reducing color shift, the thickness of the sheet for encapsulating optical semiconductor elements is preferably 5 μm to 600 μm, more preferably 10 μm to 550 μm, even more preferably 30 μm to 500 μm, even more preferably 40 μm to 450 μm, and particularly preferably 50 μm to 400 μm. The above thickness does not include the release liner.

[0189] The thickness of the sealing resin layer is, for example, 5 μm to 500 μm, preferably 10 μm to 400 μm, and more preferably 100 μm to 300 μm. When the thickness is 5 μm or greater, the sealing performance of the optical semiconductor element is improved. When the thickness is 500 μm or less, the thickness of the optical semiconductor device is further reduced.

[0190] [Release liner]

[0191] The above-mentioned sealing resin layer can be formed on the release-treated surface on the release liner. In the case where the above-mentioned sealing resin layer is formed on the above-mentioned release liner, the above-mentioned curable resin layer (X) side becomes the side in contact with the above-mentioned release liner relative to the above-mentioned adhesive layer of the above-mentioned sealing resin layer. In the case where the above-mentioned base material portion is not provided, both sides of the above-mentioned sealing resin layer can be the contact side with the release liner. The release liner is used as a protective material for the above-mentioned optical semiconductor element sealing sheet and is peeled off when the optical semiconductor element is sealed. It should be noted that a release liner is not necessarily required.

[0192] The release liner is a member for covering and protecting the surface of the optical semiconductor element sealing sheet, and is peeled from the sheet when the optical semiconductor element sealing sheet is bonded to a substrate on which an optical semiconductor element is arranged.

[0193] Examples of the release liner include plastic films such as polyethylene terephthalate (PET) film, polyethylene film, and polypropylene film, and paper, the surface of which is coated with a release agent such as a fluorine-containing release agent or a long-chain alkyl acrylate release agent.

[0194] The thickness of the release liner is, for example, 10 μm to 200 μm, preferably 15 μm to 150 μm, and more preferably 20 μm to 100 μm. When the thickness is 10 μm or greater, the release liner is less likely to break due to incisions during processing. When the thickness is 200 μm or less, the release liner is easily peeled from the optical semiconductor element encapsulating sheet during use.

[0195] Figure 1 1 is a cross-sectional view showing one embodiment of the optical semiconductor element sealing sheet of the present invention. Figure 1As shown, an optical semiconductor element sealing sheet 1 can be used to seal one or more optical semiconductor elements arranged on a substrate, and includes a base portion 4 and a sealing resin layer 2 formed on the base portion 4. The base portion 4 is composed of a base film 41 and a functional layer 42 as a surface treatment layer, but may be composed of the base film 41 alone without the functional layer 42.

[0196] exist Figure 1 In the optical semiconductor element encapsulating sheet 1 shown, the encapsulating resin layer 2 is formed of a laminate of a curable resin layer (X) 21 as a colored layer and an adhesive layer 22. The adhesive layer 22 is directly laminated on the curable resin layer (X) 21. A release liner 3 is attached to the curable resin layer (X) 21, and a base material 4 is attached to the adhesive layer 22.

[0197] exist Figure 1 In the embodiment, the functional layer 42 is a layer not included in the above-mentioned sealing resin layer, and layers that can impart various functions for sealing the above-mentioned optical semiconductor element can be listed. As the above-mentioned functional layer, for example, a layer comprising a surface treatment layer can be listed. By having such a structure, the light diffusion property for sealing the optical semiconductor element stacked with the functional layer comprising the surface treatment layer is excellent, and the light extraction efficiency is excellent. As the above-mentioned surface treatment layer, an anti-glare treatment layer (anti-glare treatment layer), an anti-reflection treatment layer, a hard coating treatment layer, etc. can be listed. The above-mentioned functional layer can be stacked on the above-mentioned sealing resin layer in the above-mentioned optical semiconductor element sealing sheet, and in the case of having the above-mentioned substrate portion, can be stacked on the above-mentioned substrate portion, preferably stacked on the above-mentioned substrate portion, preferably stacked on the side of the above-mentioned substrate portion opposite to the side where the above-mentioned sealing resin layer is provided.

[0198] [Method for producing a sheet for sealing optical semiconductor elements]

[0199] One embodiment of the method for producing the optical semiconductor element sealing sheet will be described. Figure 1 The optical semiconductor element sealing sheet 1 shown is made of a curable resin layer (X) 21 and an adhesive layer 22, each of which is sandwiched between the release-treated surfaces of two release liners. One release liner attached to the curable resin layer (X) 21 is a release liner 3. Next, one of the release liners attached to the adhesive layer 22 is peeled off to expose the surface of the adhesive layer 22, and the exposed surface is attached to the substrate portion 4. Then, one of the release liners attached to the curable resin layer (X) 21 (the release liner that is not the release liner 3) is peeled off, and the exposed surface of the curable resin layer (X) 21 is attached to the surface of the adhesive layer 22 exposed by peeling off the release liner on the surface of the adhesive layer 22. It should be noted that the stacking of various layers can be performed using a well-known roller or laminator. By doing so, a sheet in which the adhesive layer 22, the curable resin layer (X) 21 and the release liner 3 are stacked in sequence on the substrate portion 4 can be produced. Figure 1 The sheet 1 for optical semiconductor element sealing is shown.

[0200] [Optical semiconductor device]

[0201] The optical semiconductor device sealing sheet can be used to manufacture optical semiconductor devices such as image display devices. The optical semiconductor device manufactured using the optical semiconductor device sealing sheet comprises a substrate, an optical semiconductor device disposed on the substrate, and the optical semiconductor device sealing sheet for sealing the optical semiconductor device, or a cured product formed by curing the sheet. The cured product is a cured product formed by thermally curing the curable resin layer (X) 21 (or the adhesive layer 22) of the optical semiconductor device sealing sheet. Specifically, it comprises a cured sealing layer formed by thermally curing the curable resin layer (X) 21.

[0202] Examples of the optical semiconductor element include light emitting diodes (LEDs) such as a blue light emitting diode, a green light emitting diode, a red light emitting diode, and an ultraviolet light emitting diode.

[0203] In the above-mentioned optical semiconductor device, the above-mentioned optical semiconductor element sealing sheet has excellent followability to convex and concave when the optical semiconductor element is used as a convex part and the gap between multiple optical semiconductor elements is used as a concave part. The followability and embedding property of the optical semiconductor element are excellent, so it is preferred to seal multiple optical semiconductor elements collectively.

[0204] Figure 2 Indicates the use of Figure 1 One embodiment of an optical semiconductor device is a sheet 1 for sealing an optical semiconductor element shown. Figure 2 The optical semiconductor device 10 shown has a substrate 5, a plurality of optical semiconductor elements 6 arranged on one surface of the substrate 5, and a cured product of a sheet 1 for sealing an optical semiconductor element. The cured product of the optical semiconductor element sealing sheet is an object formed by peeling off the release liner 3 from the optical semiconductor element sealing sheet 1 and forming a cured sealing layer 7 by thermally curing the curable resin layer (X) 21. For example, the cured sealing layer 7 includes a cured resin layer 71 formed by thermally curing the curable resin layer (X) 21 and an adhesive layer 22. The plurality of optical semiconductor elements 6 are uniformly sealed by the cured sealing layer 7. The cured sealing layer 7 follows the concave-convex shape formed by the plurality of optical semiconductor elements 6 and adheres to the optical semiconductor element 6 and the substrate 5, and buries the optical semiconductor element 6 therein. In addition, the cured sealing layer 7 follows the above-mentioned concave-convex shape, so that the interface on the optical semiconductor element 6 side has a concave-convex shape and the other interface is flat.

[0205] It should be noted that in Figure 2In the illustrated optical semiconductor device 10, the optical semiconductor element 6 is completely embedded and sealed within the cured resin layer 71 and the adhesive layer 22. Specifically, the optical semiconductor element 6 is sealed by the cured sealing layer 7, which is a laminated body comprising the cured resin layer 71 and the adhesive layer 22. Furthermore, the cured resin layer 71 fills the space between the optical semiconductor element 6 and the substrate 5, and the space between the plurality of optical semiconductor elements 6 is filled with the cured resin layer 71 and the adhesive layer 22.

[0206] In the above-mentioned optical semiconductor device, as described above, the optical semiconductor element is sealed by the curing sealing layer. The curable resin layer (X) has sufficient flexibility before curing, and thus has excellent concave-convex tracking properties, and the optical semiconductor element is fully embedded therein. For example, by heating, the above-mentioned curable resin layer (X) acts as an underfill material, flows and fills between the optical semiconductor element 6 and the substrate 5 at the sealing temperature, and then cures, and fixes the optical semiconductor element after curing. Therefore, the optical semiconductor element is tightly attached to the curing sealing layer, and the sealing property of the optical semiconductor element is excellent. In addition, the curable resin layer (X) located on the side and upper surface of the optical semiconductor element 6 flows during sealing, thereby forming a recess between the optical semiconductor elements, and the adhesive layer is filled in the recess. As a result, it is difficult to generate gaps between the optical semiconductor element and the substrate, and between the optical semiconductor elements, and the appearance of the optical semiconductor device is excellent.

[0207] The optical semiconductor device may be formed by joining together individual optical semiconductor devices. In other words, the optical semiconductor device may be formed by arranging a plurality of optical semiconductor devices in a tile-like manner in a planar direction.

[0208] The above-mentioned image display device preferably has a self-luminous display device. In addition, by combining the above-mentioned self-luminous display device with a display panel as needed, an image display device can be formed. The optical semiconductor element in this case is an LED element. Examples of the above-mentioned self-luminous display device include: an LED display, a backlight source, or an organic electroluminescent (organic EL) display device. The above-mentioned backlight source is particularly preferably a full-surface direct-lit backlight source. The above-mentioned backlight source, for example, includes a laminate having the above-mentioned substrate and a plurality of optical semiconductor elements arranged on the substrate as at least a part of the constituent members. For example, in the above-mentioned self-luminous display device, a metal wiring layer for sending a light control signal to each LED element is stacked on the above-mentioned substrate. The LED elements emitting red (R), green (G), and blue (B) light are 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 level of each LED element to display each color.

[0209] The optical semiconductor element encapsulation sheet can be used in optical semiconductor devices that can be bent, such as bendable image display devices (flexible displays), particularly foldable image display devices (foldable displays). Specifically, it can be used in foldable backlights and foldable self-luminous display devices.

[0210] The optical semiconductor element encapsulation sheet is excellent in conformability and embedding properties of the optical semiconductor element and can therefore be preferably used in both cases where the optical semiconductor device is a small LED display device and a micro LED display device.

[0211] [Method for Manufacturing Optical Semiconductor Device]

[0212] The optical semiconductor device can be manufactured, for example, by a manufacturing method comprising the following steps: a step of laminating the optical semiconductor element sealing sheet to the optical semiconductor element disposed on the substrate to seal the optical semiconductor element with the sealing resin layer (sealing step); and a step of curing the curable resin layer in a laminate obtained through the sealing step, comprising the substrate, the optical semiconductor element disposed on the substrate, and the optical semiconductor element sealing sheet sealing the optical semiconductor element, to obtain the cured product (curing step). The cured product is a cured product formed by thermally curing the curable resin layer, and specifically comprises a cured sealing layer formed by curing the curable resin layer.

[0213] The manufacturing method may further include a step of cutting the laminated body that has undergone the curing step to obtain an optical semiconductor device (cutting step). In addition, the manufacturing method may further include a step of splicing the plurality of optical semiconductor devices obtained in the cutting step so that they are in contact with each other in the planar direction. Figure 2 A method for manufacturing the optical semiconductor device 10 shown will be described.

[0214] (Sealing process)

[0215] In the method for manufacturing an optical semiconductor device using the above-mentioned optical semiconductor element sealing sheet, there is a sealing step of laminating the above-mentioned optical semiconductor element sealing sheet to a substrate on which an optical semiconductor element is arranged, and sealing the optical semiconductor element with a sealing resin layer. In the above-mentioned sealing step, specifically, first, the release liner is peeled off from the above-mentioned optical semiconductor element sealing sheet to expose the sealing resin layer. Then, the exposed surface of the substrate surface on which the optical semiconductor element is arranged of a stacked body (optical component, etc.) having a substrate and optical semiconductor elements (preferably a plurality of optical semiconductor elements) arranged on the above-mentioned substrate is laminated. In the case where the above-mentioned stacked body has a plurality of optical semiconductor elements, the above-mentioned sealing resin layer is further arranged in a manner to fill the gaps between the plurality of optical semiconductor elements, thereby sealing the plurality of optical semiconductor elements uniformly. Specifically, the sheet is laminated from Figure 1 The curable resin layer (X) 21 exposed by peeling off the release liner 3 on the optical semiconductor element sealing sheet 1 shown is arranged opposite to the surface of the substrate 5 on which the optical semiconductor element 6 is arranged, and the optical semiconductor element sealing sheet 1 is attached to the surface of the substrate 5 on which the optical semiconductor element 6 is arranged, so that the optical semiconductor element 6 is embedded in the sealing resin layer 2 or the sealing resin layer 2 follows and adheres to the optical semiconductor element 6.

[0216] The temperature during the above-mentioned lamination (sealing temperature) is, for example, in the range of room temperature to 150°C, preferably 35°C to 120°C, more preferably 40°C to 110°C, further preferably 60°C to 105°C, and particularly preferably 70°C to 100°C. In addition, during the above-mentioned lamination, pressure reduction or pressurization may be performed. By reducing pressure or pressurization, the formation of gaps between the sealing resin layer and the substrate or optical semiconductor element can be suppressed. In addition, in the above-mentioned sealing process, it is preferred to laminate the optical semiconductor element sealing sheet under reduced pressure and then pressurize it. The pressure in the case of reduced pressure is, for example, 1Pa to 100Pa, and the time for reducing pressure is, for example, 5 seconds to 600 seconds. In addition, the pressure in the case of pressurization is, for example, 0.05MPa to 0.5MPa, and the time for pressurization is, for example, 5 seconds to 600 seconds. Through this sealing process, the curable resin layer (X) flows at the sealing temperature and fills the space between the optical semiconductor element and the substrate.

[0217] (Curing process)

[0218] In the curing step, the laminate (e.g., the laminate obtained in the sealing step) in which the optical semiconductor element sealing sheet is bonded to the substrate on which the optical semiconductor element is arranged is heated to cure the curable resin layer and, if necessary, the adhesive layer. Figure 2As shown, the curable resin layer (X) 21 is cured to form a cured sealing layer 7, thereby obtaining a cured product of the optical semiconductor element sealing sheet 1. When the curable resin layer is thermosetting, the heating temperature during the curing is, for example, in the range of 80°C to 200°C, and the heating time is, for example, 1 minute to 24 hours.

[0219] (Cutting process)

[0220] In the above-mentioned cutting process, the laminated body that has undergone the above-mentioned curing process is cut. Here, in the laminated body supplied to the cutting process, the cured product of the optical semiconductor element sealing sheet and the substrate 5 extend wider in the plane direction than the optical semiconductor device 10 finally obtained. Then, in the above-mentioned cutting process, the cured product of the optical semiconductor element sealing sheet and the side end portions of the substrate are cut and removed. The above-mentioned cutting can be performed by a known or customary method, for example, by using a cutting blade or laser irradiation. By doing so, for example, it is possible to manufacture Figure 2 The optical semiconductor device 10 is shown.

[0221] (Splicing process)

[0222] In the splicing step, the plurality of optical semiconductor devices obtained in the dicing step are arranged and spliced so as to be in contact with each other in the planar direction. By doing so, for example, a large image display device can be manufactured.

[0223] Example

[0224] The present invention is described in more detail with reference to the following examples, but the present invention is not limited by these examples.

[0225] Production Example 1

[0226] (Preparation of Acrylic Prepolymer Solution A)

[0227] Into a separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube were added 67 parts by mass of butyl acrylate (BA), 14 parts by mass of cyclohexyl acrylate (CHA), 19 parts by mass of 4-hydroxybutyl acrylate (4-HBA), 0.09 parts by mass of a photopolymerization initiator (trade name "omnirad184", manufactured by IGM Resins Itaila Srl), and 0.09 parts by mass of a photopolymerization initiator (trade name "omnirad651", manufactured by IGM Resins Itaila Srl), and then nitrogen was passed through and nitrogen replacement was performed for about 1 hour while stirring. Then, at 5 mW / cm 2 The polymerization was carried out by irradiation with ultraviolet rays, and the reaction rate was adjusted to 5% to 15%, thereby obtaining an acrylic prepolymer solution A.

[0228] Production Example 2

[0229] (Preparation of Adhesive Composition A)

[0230] To the acrylic prepolymer solution A prepared in Production Example 1 (the total amount of the prepolymer was 100 parts by mass), 9 parts by mass of 2-hydroxyethyl acrylate (HEA), 8 parts by mass of 4-hydroxybutyl acrylate (4HBA), 0.02 parts by mass of dipentaerythritol hexaacrylate (trade name "KAYARAD DPHA", manufactured by Shin-Nakamura Chemical Co., Ltd.) as a multifunctional monomer, 0.35 parts by mass of a silane coupling agent (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyltrimethoxysilane), and 0.3 parts by mass of a photopolymerization initiator (trade name "omnirad 651", manufactured by IGM Resins Itaila Srl) were added to obtain an adhesive composition A.

[0231] Production Example 3

[0232] (Preparation of Adhesive Layer A)

[0233] 38.2 parts by mass of the adhesive composition A prepared in Production Example 2 were mixed with 23 parts by mass of "Tospearl 145" (a silicone resin manufactured by Momentive Advanced Materials Co., Ltd., with a refractive index of 1.42 and an average particle size of 4.5 μm), 23 parts by mass of benzyl acrylate (BzA), 15.7 parts by mass of butyl acrylate (BA), 0.02 parts by mass of dipentaerythritol hexaacrylate (KAYARAD DPHA, manufactured by Shin-Nakamura Chemical Co., Ltd.) as a multifunctional monomer, and 0.09 parts by mass of a photopolymerization initiator (OMNIRAD 651, manufactured by IGM Resins Itaila Srl) to obtain an adhesive composition. The adhesive composition was applied to the release-treated surface of a release liner (trade name "MRE38", manufactured by Mitsubishi Chemical Corporation, a release liner obtained by applying a release treatment on one side of a polyethylene terephthalate film, thickness 38 μm) to form a resin composition layer. The release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was then attached to the resin composition layer. Subsequently, ultraviolet light was irradiated using a black light lamp until the accumulated light intensity reached 2520 mJ / cm 2 Polymerization was performed to produce an adhesive layer A (thickness 50 μm).

[0234] Production Example 4

[0235] (Preparation of Adhesive Layer B)

[0236] 38.2 parts by mass of the adhesive composition A prepared in Production Example 2 were mixed with 23 parts by mass of "Tospearl 145" (a silicone resin manufactured by Momentive Advanced Materials Co., Ltd., with a refractive index of 1.42 and an average particle size of 4.5 μm), 23 parts by mass of benzyl acrylate (BzA), 15.7 parts by mass of butyl acrylate (BA), and 0.2 parts by mass of dipentaerythritol hexaacrylate (trade name "KAYARAD DPHA", manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) as a multifunctional monomer to obtain an adhesive composition. The adhesive composition was applied to the release-treated surface of a release liner (trade name "MRE38", manufactured by Mitsubishi Chemical Corporation, a release liner obtained by applying a release treatment on one side of a polyethylene terephthalate film, thickness 38 μm) to form a resin composition layer. The release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was then attached to the resin composition layer. Subsequently, ultraviolet light was irradiated using a black light lamp until the accumulated light intensity reached 2520 mJ / cm 2 Polymerization was performed to produce an adhesive layer B (50 μm in thickness).

[0237] Production Example 5

[0238] (Preparation of Thermosetting Resin Layer A)

[0239] 63.9 parts by mass of an acrylic polymer (glycidyl methacrylate (GMA): ethyl acrylate (EA): butyl methacrylate (BMA) = 34% by mass: 30% by mass: 36% by mass, weight-average molecular weight 60,000), 34.1 parts by mass of an acrylic resin (trade name "UC-3000", a carboxyl group-containing acrylic resin, weight-average molecular weight 10,000, manufactured by Toagosei Co., Ltd.), 2.0 parts by mass of a silane coupling agent (trade name "KBM-303", manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.04 parts by mass of "Carbon Black #20" (Mitsubishi Chemical Corporation) were dissolved in methyl ethyl ketone to prepare a resin composition solution having a solid content concentration of 50% by mass. The above-mentioned resin composition solution was applied to the release-treated surface of a release liner (a release-treated film comprising a polyethylene terephthalate film with a thickness of 38 μm that had been subjected to a silicone release treatment) and then dried at 130° C. for 2 minutes to produce a sheet-like thermosetting resin layer A with a thickness (average thickness) of 110 μm.

[0240] Production Example 6

[0241] (Preparation of Thermosetting Resin Layer B)

[0242] 63.9 parts by mass of an acrylic polymer (glycidyl methacrylate (GMA): ethyl acrylate (EA): butyl methacrylate (BMA) = 34% by mass: 30% by mass: 36% by mass, weight-average molecular weight 60,000), 19.1 parts by mass of an acrylic resin (trade name "UC-3000", a carboxyl group-containing acrylic resin, weight-average molecular weight 10,000, manufactured by Toagosei Co., Ltd.), 15.0 parts by mass of an acrylic resin (trade name "UC-3510", a carboxyl group-containing acrylic resin, weight-average molecular weight 2,000, manufactured by Toagosei Co., Ltd.), 2.0 parts by mass of a silane coupling agent (trade name "KBM-303", manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.04 parts by mass of "Carbon Black #20" (Mitsubishi Chemical Corporation) were dissolved in methyl ethyl ketone to prepare a resin composition solution having a solid content concentration of 50% by mass. The above-mentioned resin composition solution was applied to the release-treated surface of a release liner (a release-treated film comprising a polyethylene terephthalate film with a thickness of 38 μm and subjected to a silicone release treatment), and then dried at 130°C for 2 minutes to produce sheet-shaped thermosetting resin layers B having thicknesses (average thickness) of 60 μm, 70 μm, 75 μm, and 110 μm, respectively.

[0243] Production Example 7

[0244] (Preparation of Thermosetting Resin Layer C)

[0245] 63.9 parts by mass of an acrylic polymer (glycidyl methacrylate (GMA): ethyl acrylate (EA): butyl methacrylate (BMA) = 34% by mass: 30% by mass: 36% by mass, weight-average molecular weight 60,000), 34.1 parts by mass of an acrylic resin (trade name "UC-3000", a carboxyl group-containing acrylic resin, weight-average molecular weight 10,000, manufactured by Toagosei Co., Ltd.), 2.0 parts by mass of a silane coupling agent (trade name "KBM-303", manufactured by Shin-Etsu Chemical Co., Ltd.), and 20.0 parts by mass of "Tospearl 145" (a silicone resin manufactured by Momentive Advanced Materials Co., Ltd., with a refractive index of 1.42 and an average particle size of 4.5 μm) were dissolved in methyl ethyl ketone to prepare a resin composition solution having a solid content concentration of 50% by mass. The above-mentioned resin composition solution was applied to the release-treated surface of a release liner (a release-treated film comprising a polyethylene terephthalate film with a thickness of 38 μm that had been subjected to a silicone release treatment) and then dried at 130° C. for 2 minutes to produce a sheet-like thermosetting resin layer C with a thickness (average thickness) of 160 μm.

[0246] Example 1

[0247] (Production of Sheet for Sealing Optical Semiconductor Element)

[0248] One release liner (trade name "MRE38") was peeled off from the adhesive layer A obtained in Production Example 3, and the exposed adhesive surface was attached to the adhesion-facilitating surface of the base film A (trade name "T912 E75 (UE80)", PET film, manufactured by Mitsubishi Chemical Corporation).

[0249] Next, the release liner (trade name "MRF38") was peeled off from the surface of the adhesive layer A to expose the adhesive surface. The exposed surface of the thermosetting resin layer A obtained in Production Example 5 was then overlapped with the exposed surface of the adhesive layer A, and a hand roller was used to adhere the sheets at room temperature (23°C) without introducing air bubbles. The sheets were then placed under light-shielding conditions for 2 days. This gave the optical semiconductor element encapsulation sheet of Example 1 comprising [release liner / thermosetting resin layer A (110 μm) / adhesive layer A (50 μm) / base film A].

[0250] Example 2

[0251] (Production of Sheet for Sealing Optical Semiconductor Element)

[0252] Except having used the thermosetting resin layer B (thickness 110 micrometers) obtained in Production Example 6 instead of the thermosetting resin layer A, it carried out similarly to Example 1, and produced the sheet for optical semiconductor element sealing of Example 2.

[0253] Example 3

[0254] (Production of Sheet for Sealing Optical Semiconductor Element)

[0255] Except having used the thermosetting resin layer B (thickness 75 micrometers) obtained in Manufacturing Example 6 instead of the thermosetting resin layer A, it carried out similarly to Example 1, and produced the sheet for optical semiconductor element sealing of Example 3.

[0256] Example 4

[0257] (Production of Sheet for Sealing Optical Semiconductor Element)

[0258] A sheet for optical semiconductor element sealing of Example 4 was produced in the same manner as in Example 3 except that the adhesive layer B obtained in Production Example 4 was used instead of the adhesive layer A.

[0259] Example 5

[0260] (Production of Sheet for Sealing Optical Semiconductor Element)

[0261] Except having used the thermosetting resin layer B with a thickness of 60 μm, it carried out similarly to Example 4, and produced the sheet for optical semiconductor element sealing of Example 5.

[0262] Example 6

[0263] (Production of Sheet for Sealing Optical Semiconductor Element)

[0264] A sheet for optical semiconductor element sealing of Example 6 was produced in the same manner as in Example 4 except that the thermosetting resin layer B having a thickness of 70 μm was used.

[0265] Comparative Example 1

[0266] (Production of Sheet for Sealing Optical Semiconductor Element)

[0267] The exposed surface of the thermosetting resin layer C obtained in Production Example 7 was bonded to the easily adhesive surface of the base film A and left for two days under light-shielding conditions. This gave a sheet for encapsulating an optical semiconductor element of Comparative Example 1 comprising [release liner / thermosetting resin layer C (160 μm) / base film A].

[0268] <Evaluation>

[0269] The following evaluations were performed on the optical semiconductor element encapsulation sheets produced in Examples and Comparative Examples. The results are shown in Table 1.

[0270] (1) Gel fraction

[0271] Approximately 0.1 g of the adhesive layer was collected from the optical semiconductor element sealing sheet. This was wrapped with a porous tetrafluoroethylene sheet (trade name "NTF1122," manufactured by Nitto Denko Corporation) with an average pore size of 0.2 μm. The resulting material was then tied with kite string. The weight at this point was measured and used as the pre-immersion weight. This pre-immersion weight is the total weight (Z) of the adhesive layer (the collected adhesive layer), the tetrafluoroethylene sheet, and the kite string. The combined weight of the tetrafluoroethylene sheet and the kite string was also measured and used as the packaging bag weight (Y).

[0272] Next, the adhesive layer was wrapped with a tetrafluoroethylene sheet and tied with a kite string (referred to as a "sample"), placed in a 50 ml container filled with ethyl acetate and allowed to stand at 23°C for 7 days. The sample (after ethyl acetate treatment) was then removed from the container, transferred to an aluminum cup, and dried in a dryer at 130°C for 2 hours to remove the ethyl acetate. The weight was then measured and designated as the post-immersion weight (X).

[0273] Then, the gel fraction was calculated according to the following formula.

[0274] Gel fraction [% (weight %)] = (XY) / (ZY) × 100

[0275] (2) Viscosity

[0276] The viscosity of the thermosetting resin layer at the sealing temperature shown in Table 1 was measured. Specifically, approximately 0.1 g of the thermosetting resin layer was collected from the optical semiconductor element sealing sheet and placed on parallel plates (8 mm in diameter) as a measuring plate. The melt viscosity (Pa·s) of this sample at the sealing temperature was measured using a rheometer (trade name "RheoStress 6000," manufactured by HAAKE) using the parallel plate method. The measurement was performed with a gap of 0.5 mm between the parallel plates, a strain rate of 0.1 / s, a heating rate of 5°C / min, and a measurement temperature range of 40°C to 150°C.

[0277] (3) Appearance

[0278] The release liner was removed from the optical semiconductor element sealing sheet, and the exposed surface of the thermosetting resin layer was bonded to an adherend (8-inch wafer) with the protrusions processed to the heights shown in Table 1. The bonding was performed using the "MSV300" equipment manufactured by Nitto Seiki Co., Ltd., with the wafer surface temperature set to the sealing temperature shown in Table 1, and differential pressure bonding was performed. The differential pressure bonding conditions were set to a vacuum of 20 Pa and a bonding pressure of 0.1 MPa. This procedure produced an optical semiconductor device sample.

[0279] The optical semiconductor device samples were visually observed between the convex portions of the adherend. A case where no voids were observed between the convex portions was evaluated as "○", and a case where voids were observed was evaluated as "×".

[0280]

[0281] As shown in Table 1, when the viscosity of the thermosetting resin layer of the optical semiconductor element sealing sheet of the embodiment at the sealing temperature is within a specific range, when sealing is performed at the sealing temperature, no gaps are generated between the protrusions in the optical semiconductor device sample, and the appearance is good. In contrast, when the viscosity of the thermosetting resin layer at the sealing temperature is less than 2 kPa·s, when sealing is performed at the sealing temperature, gaps are present between the protrusions in the optical semiconductor device sample, and the appearance is evaluated as poor. In addition, in the case of using an optical semiconductor element sealing sheet that does not have an adhesive layer on the side of the thermosetting resin layer opposite to the adherend (Comparative Example 1), it is also evaluated that there are gaps between the protrusions in the optical semiconductor device sample, and the appearance is poor. It should be noted that the optical semiconductor element sealing sheets in all embodiments and comparative examples use materials that fully exert the function of the bottom filling material.

[0282] Hereinafter, modifications of the present invention will be described.

[0283] [Supplementary Note 1] A sheet for sealing an optical semiconductor element, the sheet being used to seal one or more optical semiconductor elements arranged on a substrate, wherein the sheet has a sealing resin layer comprising at least a curable resin layer and an adhesive layer, and the viscosity of the curable resin layer at the sealing temperature is 2 kPa·s to 2000 kPa·s.

[0284] [Supplementary Note 2] The optical semiconductor element sealing sheet according to Supplementary Note 1, wherein the curable resin layer is located on the optical semiconductor element side with respect to the adhesive layer.

[0285] [Supplementary Note 3] The optical semiconductor element sealing sheet according to Supplementary Note 1 or 2, wherein the curable resin layer has thermosetting properties.

[0286] [Appendix 4] The sheet for optical semiconductor element sealing according to any one of Appendices 1 to 3, wherein the curable resin layer contains a black colorant.

[0287] [Supplementary Note 5] The sheet for optical semiconductor element sealing according to any one of Supplementary Notes 1 to 4, wherein the pressure-sensitive adhesive layer is a non-colored pressure-sensitive adhesive layer.

[0288] [Supplementary Note 6] The sheet for optical semiconductor element sealing according to any one of Supplementary Notes 1 to 5, wherein the pressure-sensitive adhesive layer is a diffusion function layer.

[0289] [Supplementary Note 7] The optical semiconductor element sealing sheet according to any one of Supplementary Notes 1 to 6, wherein the light transmittance of the curable resin layer at a wavelength of 600 nm after curing is 0% to 80%.

[0290] [Supplementary Note 8] The sheet for encapsulating an optical semiconductor element according to any one of Supplementary Notes 1 to 7, wherein in a state where an optical semiconductor element is encapsulated, a distance from the optical semiconductor element to the curable resin layer is 0 μm to 20 μm.

[0291] [Supplementary Note 9] The optical semiconductor element sealing sheet according to any one of Supplementary Notes 1 to 8, wherein the thickness of the adhesive layer is 30% or more of the distance from the surface of the substrate to the apex of the optical semiconductor element.

[0292] [Supplementary Note 10] The optical semiconductor element sealing sheet according to any one of Supplementary Notes 1 to 9, wherein the curable resin layer has a thickness of 70 μm to 150 μm.

[0293] [Supplementary Note 11] The optical semiconductor element sealing sheet according to any one of Supplementary Notes 1 to 10, wherein the adhesive layer has a thickness of 30 μm to 100 μm.

[0294] [Supplementary Note 12] The optical semiconductor element sealing sheet according to any one of Supplementary Notes 1 to 11, comprising a base material portion and the sealing resin layer laminated on the base material portion.

[0295] [Supplementary Note 13] The optical semiconductor element sealing sheet according to Supplementary Note 12, wherein the adhesive layer is located on the side of the base material portion with respect to the curable resin layer.

[0296] [Supplementary Note 14] An optical semiconductor device comprising: a substrate; an optical semiconductor element disposed on the substrate; and the optical semiconductor element sealing sheet or a cured product thereof according to any one of Supplementary Notes 1 to 13 for sealing the optical semiconductor element.

Claims

1. A sheet for sealing an optical semiconductor element, the sheet being used for sealing one or more optical semiconductor elements arranged on a substrate, wherein: The sheet has a sealing resin layer including at least a curable resin layer and an adhesive layer. The viscosity of the curable resin layer at the sealing temperature is 2 kPa·s to 2000 kPa·s.

2. The optical semiconductor element sealing sheet according to claim 1, wherein The curable resin layer is located on the optical semiconductor element side relative to the adhesive layer.

3. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The curable resin layer has thermosetting properties.

4. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The curable resin layer contains a black colorant.

5. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The adhesive layer is a non-colored adhesive layer.

6. The optical semiconductor element sealing sheet according to claim 5, wherein The adhesive layer is a diffusion function layer.

7. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The curable resin layer has a light transmittance of 0% to 80% at a wavelength of 600 nm after curing.

8. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein In a state where the optical semiconductor element is sealed, a distance from the optical semiconductor element to the curable resin layer is 0 μm to 20 μm.

9. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The thickness of the adhesive layer is 30% or more of the distance from the surface of the substrate to the top of the optical semiconductor element.

10. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The curable resin layer has a thickness of 70 μm to 150 μm.

11. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The thickness of the adhesive layer is 30 μm to 100 μm.

12. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The optical semiconductor element sealing sheet includes a base portion and the sealing resin layer laminated on the base portion.

13. The optical semiconductor element sealing sheet according to claim 12, wherein The adhesive layer is located on the base material side relative to the curable resin layer.

14. An optical semiconductor device, wherein: The optical semiconductor device includes: a substrate; an optical semiconductor element disposed on the substrate; and the optical semiconductor element sealing sheet according to any one of claims 1 to 13 or a cured product thereof for sealing the optical semiconductor element.

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