Optical semiconductor element sealing sheet

Abstract

The present invention provides a sheet for sealing optical semiconductor elements, which has excellent sealing properties for optical semiconductor elements and is less likely to cause sheet damage and adhesion of adjacent optical semiconductor devices when adjacent optical semiconductor devices are separated from each other. The sheet (1) for sealing optical semiconductor elements is a sheet used to seal one or more optical semiconductor elements (6) arranged on a substrate (5). The sheet (1) for sealing optical semiconductor elements comprises a substrate portion (2) and a sealing portion (3), wherein the sealing portion (3) is arranged on one surface of the substrate portion (2). The sealing portion (3) is used to seal the optical semiconductor element (6), and comprises a radiation non-curing adhesive layer (32) and a radiation curing resin layer (31). The radiation curing resin layer (31) contains a polymer having a radiation polymerizable functional group.

Description

Technical Field

[0001] The present invention relates to a sheet for sealing an optical semiconductor element, and more specifically, to a sheet for sealing one or more optical semiconductor elements arranged on a substrate. Background Art

[0002] For example, it is known that a backlight used in a liquid crystal display device has the following structure: a plurality of LEDs are arranged on a substrate, and the plurality of LEDs are sealed with a sealing resin. As a method of sealing the plurality of LEDs together using the sealing resin, the following method is known: after a liquid resin is poured into a region where the plurality of LEDs are arranged to bury the plurality of LEDs, the liquid resin is cured by heat or ultraviolet irradiation (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-66390 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, the method of sealing optical semiconductor elements such as LEDs using liquid resin has problems such as dripping of the liquid when applying the liquid resin and adhesion of the liquid resin to unexpected areas, which results in poor handling properties.

[0008] In this regard, it can be considered that: by presenting a sealing sheet having a sealing layer for sealing the optical semiconductor element without using a liquid resin, it is easy to seal the optical semiconductor element in a simple process and in a short time. What is important here is that the optical semiconductor element sealing property of the sealing sheet is excellent, and in order to fully seal the optical semiconductor element, it has excellent adhesion to the optical semiconductor element and the substrate having the optical semiconductor element.

[0009] However, with the trend toward higher image quality such as 4K and 8K, the demand for image display devices with larger screens is increasing. In addition, the use of large-screen image display devices in outdoor advertising displays, bulletin boards and other signs in public facilities is also advancing. However, if a large-screen image display device is manufactured, the yield rate will decrease and the manufacturing cost will increase. In order to manufacture large-screen image display devices at a lower cost, a tiling display (Tiling display) in which multiple optical semiconductor devices such as image display devices are arranged in a tile shape has been studied. When multiple optical semiconductor devices are arranged in a tile shape, that is, tiled, if adjacent optical semiconductor devices are misaligned with each other and need to be rearranged, position correction is performed.

[0010] Here, when laying out an optical semiconductor device in a state where an optical semiconductor element is sealed by a sealing sheet, it is necessary to temporarily separate the adjacent optical semiconductor devices in order to correct the position when laying out. However, during separation, the following undesirable situations may occur: the sealing sheet in one optical semiconductor device is tightly attached to the sealing sheet in another adjacent optical semiconductor device and they are pulled against each other, the sealing sheet in one optical semiconductor device is damaged, and a part of one sealing sheet is transferred and attached to another optical semiconductor device. This undesirable situation is particularly prone to occur for a sealing sheet that has excellent adhesion to an optical semiconductor element and a substrate.

[0011] The present invention has been conceived based on such circumstances, and its object is to provide an optical semiconductor element sealing sheet which has excellent sealing properties for optical semiconductor elements and which is less likely to cause sheet damage and adhesion of sheets of adjacent optical semiconductor devices when adjacent optical semiconductor devices are separated from each other.

[0012] Solutions for solving problems

[0013] The inventors of the present invention have conducted intensive research to achieve the above-mentioned object, and as a result, have found that a sheet for sealing an optical semiconductor element having a sealing portion including a radiation non-curing adhesive layer and a radiation curing resin layer, wherein the radiation curing resin layer includes a polymer having a radiation polymerizable functional group, has excellent sealing properties for an optical semiconductor element, and when adjacent optical semiconductor devices are separated from each other, it is less likely that the sheet will be damaged and the sheet of the adjacent optical semiconductor device will adhere. The present invention has been completed based on these findings.

[0014] That is, the present invention provides a sheet for sealing an optical semiconductor element, which is a sheet for sealing one or more optical semiconductor elements arranged on a substrate.

[0015] The optical semiconductor device comprises a base material and a sealing part for sealing the optical semiconductor element provided on one surface of the base material.

[0016] The sealing portion comprises a radiation non-curing adhesive layer and a radiation curing resin layer.

[0017] The radiation-curable resin layer contains a polymer having a radiation-polymerizable functional group.

[0018] As described above, the optical semiconductor element sealing sheet has a sealing portion in which a radiation non-curing adhesive layer and a radiation curing resin layer are stacked. The sealing portion is a region in the optical semiconductor element sealing sheet. Furthermore, the radiation curing resin layer contains a polymer having a radiation polymerizable functional group. The polymer having a radiation polymerizable functional group present in the radiation curing resin layer is not easily transferred from the radiation curing resin layer to the radiation non-curing adhesive layer stacked on the layer. Therefore, when radiation irradiation is performed after the sealing of the optical semiconductor element, the radiation curing resin layer is fully cured, the adhesion of the side of the sealing sheet is reduced, and the unexpected curing of the radiation non-curing adhesive layer is suppressed, thereby the adhesive force is not easily reduced, the original adhesion can be exerted, and the sealing of the optical semiconductor element is excellent. Thus, while the optical semiconductor element has excellent sealing performance, the side surfaces of the sealing parts in the adjacent optical semiconductor devices in the flat state have low adhesion to each other, so that when the adjacent optical semiconductor devices are separated from each other, it is not easy for the sheet on the side surface of the optical semiconductor device to be damaged or for the sheet of the adjacent optical semiconductor device to be attached. In addition, the substrate portion serves as a support for the sealing part, and the optical semiconductor element sealing sheet has excellent handling performance by having the substrate portion. In addition, when the optical semiconductor element is sealed with the optical semiconductor element sealing sheet to produce an optical semiconductor device and then cut, adhesion of the cut portion can be suppressed, and an optical semiconductor device with a good appearance can be produced.

[0019] The radiation-curable resin layer is preferably thicker than the radiation-non-curable adhesive layer. With such a structure, the low adhesion of the radiation-curable resin layer in the adjacent optical semiconductor device after curing becomes dominant compared to the high adhesion of the radiation-non-curable adhesive layers in the adjacent optical semiconductor devices in a flat state. Therefore, the adhesion between the sealed parts is lower, making it less likely for the sheet to be damaged or the sheet of the adjacent optical semiconductor device to adhere when the adjacent optical semiconductor devices are separated from each other. In addition, when the optical semiconductor device is manufactured by sealing the optical semiconductor element with the optical semiconductor element sealing sheet and then cutting it, the adhesion of the cut part can be further suppressed, and an optical semiconductor device with a good appearance can be manufactured.

[0020] The sealing portion may include a layer containing a colorant. With such a structure, when the optical semiconductor device is laid flat and applied to a display, it is possible to suppress the color mixing of light emitted by each optical semiconductor element when the optical semiconductor device is used, and to adjust the appearance of the display when the optical semiconductor device is not used.

[0021] The optical semiconductor element sealing sheet preferably has an anti-glare and / or anti-reflection layer. With such a structure, when the optical semiconductor device is laid flat and applied to a display, the gloss and light reflection of the display can be suppressed, and the appearance of the display can be improved.

[0022] The optical semiconductor element sealing sheet preferably has a layer with a polyester resin and / or a polyimide resin as the main component. With such a structure, the optical semiconductor element sealing sheet has excellent heat resistance, can suppress the thermal expansion of the optical semiconductor element sealing sheet in a high temperature environment, and improves dimensional stability. In addition, the sheet can be given rigidity, so that the handling and retention properties are improved.

[0023] The hardness of the cross section of the radiation-curable resin layer after curing is preferably 1.4 MPa or more at a temperature of 23° C. by a nanoindentation method. With such a configuration, the radiation-curable resin layer has an appropriate hardness after curing, so that when adjacent optical semiconductor devices are separated from each other in a flat state, sheet defects and adhesion of adjacent optical semiconductor devices are less likely to occur.

[0024] In addition, the present invention provides an optical semiconductor device, comprising: a substrate; an optical semiconductor element disposed on the substrate; and a cured product obtained by curing the radiation-curable resin layer of the optical semiconductor element sealing sheet that seals the optical semiconductor element. When the adjacent optical semiconductor devices are separated from each other after curing the radiation-curable resin, the optical semiconductor device is less likely to have a sheet defect or sheets of adjacent optical semiconductor devices adhere. In addition, adhesion of the cut portion can be suppressed during cutting, and an optical semiconductor device with a good appearance can be manufactured.

[0025] The optical semiconductor device may be a backlight of a liquid crystal screen. In addition, the optical semiconductor device may be a self-luminous display device. When the optical semiconductor device is applied to an optical semiconductor device with a display, the appearance is good, and therefore, the optical semiconductor device may be preferably used as a backlight of a liquid crystal screen or a self-luminous display device.

[0026] Furthermore, the present invention provides an image display device including the above-mentioned backlight and a display panel.

[0027] Furthermore, the present invention provides an image display device including the self-luminous display device.

[0028] Effects of the Invention

[0029] According to the optical semiconductor element sealing sheet of the present invention, the optical semiconductor element has excellent sealing performance, and when adjacent optical semiconductor devices are separated from each other, the sheet is not easily damaged and the sheet of adjacent optical semiconductor devices is not easily attached. Therefore, after the optical semiconductor devices are laid flat, if the adjacent optical semiconductor devices are misaligned or need to be rearranged, there is no problem, the position can be easily corrected, the loss of the optical semiconductor device can be reduced, and a display with excellent economic performance and good appearance can be manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a cross-sectional view of a sheet for sealing an optical semiconductor element according to one embodiment of the present invention.

[0031] Figure 2 This is a cross-sectional view of an optical semiconductor device using the optical semiconductor element sealing sheet according to one embodiment of the present invention.

[0032] Figure 3 It is shown Figure 2 The optical semiconductor device shown is an external view of one embodiment of an optical semiconductor device produced by laying out the optical semiconductor device.

[0033] Figure 4 A cross-sectional view showing a state of a sealing step in one embodiment of a method for manufacturing an optical semiconductor device is shown.

[0034] Figure 5 Shows the representation Figure 4 sectional view of the laminate obtained after the sealing step shown.

[0035] Figure 6 Show that Figure 5 The laminate shown is a cross-sectional view of a laminate obtained by subjecting the laminate to a radiation irradiation step.

[0036] Figure 7 Shows the representation Figure 6 A cross-sectional view showing a cutting position in a cutting step of a stacked body shown.

[0037] Description of Reference Numerals

[0038] 1 Sheet for sealing optical semiconductor elements

[0039] 1' Cured product of sheet for sealing optical semiconductor element

[0040] 2 Base material

[0041] 21 Optical Film

[0042] 22 Adhesive layer

[0043] 23 Plastic film

[0044] 3. Sealing part

[0045] 31 Radiation curable resin layer

[0046] 31' Curing seal layer

[0047] 32 Radiation non-curing adhesive layer

[0048] 4 Release liner

[0049] 5 substrate

[0050] 6 Optical semiconductor devices

[0051] 10, 20 Optical semiconductor devices DETAILED DESCRIPTION

[0052] [Sheet for sealing optical semiconductor elements]

[0053] The optical semiconductor element sealing sheet of the present invention comprises at least a substrate portion and a sealing portion, wherein the sealing portion is used to seal an optical semiconductor element disposed on one surface of the substrate portion. 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 disposed on a substrate. In addition, in this specification, "sealing an optical semiconductor element" means burying at least a portion of the optical semiconductor element in the sealing portion.

[0054] In the optical semiconductor element sealing sheet of the present invention, in addition to the substrate portion and the sealing portion, a release liner may also be provided. In this case, the release liner is attached to the surface of the sealing portion on the opposite side of the substrate portion. The release liner is used as a protective material for the sealing portion and is peeled off when the optical semiconductor element is sealed. It should be noted that a release liner is not necessarily provided.

[0055] In addition, the optical semiconductor element sealing sheet of the present invention may have a surface protection film on the surface of the substrate portion (the surface on the opposite side of the sealing portion). When the substrate portion is used, for example, an optical film described later, the optical film can be protected until it is used. It should be noted that a surface protection film is not necessarily required.

[0056] Hereinafter, one embodiment of the sheet for optical semiconductor element sealing of the present invention will be described. 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, the 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 material portion 2, a sealing portion 3, and a release liner 4. The sealing portion 3 is provided on one surface of the base material portion 2. The release liner 4 is attached to the surface of the sealing portion 3 (the surface on the side opposite to the side having the base material portion 2). In other words, the optical semiconductor element sealing sheet 1 includes the base material portion 2, the sealing portion 3, and the release liner 4 in sequence. The base material portion 2 is a multilayer having an optical film 21 and a plastic film 23, and the optical film 21 and the plastic film 23 are bonded together by means of an adhesive layer 22. The sealing portion 3 is composed of a radiation curable resin layer 31 and a radiation non-curable adhesive layer 32.

[0057] The optical semiconductor element sealing sheet preferably has an anti-glare and / or anti-reflection layer. By having such a structure, when the optical semiconductor device is laid out and applied to a display, the gloss of the display and the reflection of light can be suppressed, and the appearance of the display can be improved. As the above-mentioned anti-glare layer, an anti-glare treatment layer can be listed. As the above-mentioned anti-reflection layer, an anti-reflection treatment layer can be listed. The anti-glare treatment and the anti-reflection treatment can be implemented respectively using known and / or customary methods. The above-mentioned anti-glare layer and the above-mentioned anti-reflection layer can be the same layer or different layers. The above-mentioned anti-glare and / or anti-reflection layer can have only one layer or two or more layers.

[0058] The above-mentioned layer having anti-glare and / or anti-reflection properties can be a layer contained in the above-mentioned substrate portion, a layer contained in the above-mentioned sealing portion, or any one of other layers not contained in the above-mentioned substrate portion and the above-mentioned sealing portion, preferably a layer contained in the above-mentioned substrate portion and / or the above-mentioned sealing portion, and more preferably a layer contained in the above-mentioned substrate portion.

[0059] The optical semiconductor element sealing sheet preferably has a layer with polyester resin and / or polyimide resin as the main component (the component with the highest mass ratio among the constituent resins). By having such a structure, the heat resistance of the optical semiconductor element sealing sheet is excellent, the thermal expansion of the optical semiconductor element sealing sheet can be suppressed in a high temperature environment, and the dimensional stability is improved. In addition, the rigidity of the sheet can be imparted, so the handling and retention properties are improved. The layer with the polyester resin and / or polyimide resin as the main component may have only one layer or may have two or more layers.

[0060] The layer having the above-mentioned polyester resin and / or polyimide resin as the main component may be a layer contained in the above-mentioned base material portion, a layer contained in the above-mentioned sealing portion, or any one of other layers not contained in the above-mentioned base material portion and the above-mentioned sealing portion, preferably a layer contained in the above-mentioned base material portion and / or the above-mentioned sealing portion, and more preferably a layer contained in the above-mentioned base material portion.

[0061] <Sealing section>

[0062] The sealing portion includes a resin layer having a property of being cured by irradiation with radiation (radiation-curable resin layer) and an adhesive layer having no property of being cured by irradiation with radiation (radiation-uncurable adhesive layer).

[0063] (Radiation Curable Resin Layer)

[0064] The radiation-curable resin layer contains at least a polymer having a radiation-polymerizable functional group. The polymer having a radiation-polymerizable functional group present in the radiation-curable resin layer is difficult to transfer from the radiation-curable resin layer to the radiation-non-curable adhesive layer stacked on the layer. Therefore, when radiation irradiation is performed after the sealing of the optical semiconductor element, the radiation-curable resin layer is fully cured, the adhesion of the side of the sealing sheet is reduced, and the unexpected curing of the radiation-non-curable adhesive layer is suppressed, so that the adhesive force is not easy to decrease, the original adhesion can be exerted, and the sealing of the optical semiconductor element is excellent. As a result, while the sealing of the optical semiconductor element is excellent, the side surfaces of the sealing parts in the adjacent optical semiconductor devices in a flat state have low adhesion to each other, and when the adjacent optical semiconductor devices are separated from each other, it is not easy to cause the sheet on the side of the optical semiconductor device to be damaged or the sheet of the adjacent optical semiconductor device to be attached.

[0065] On the other hand, when using the conventional radiation curable resin layer, the above-mentioned monomers and oligomers with radiation polymerizability are easily transferred to the laminated radiation non-curable adhesive layer, wherein the conventional radiation curable resin layer contains a polymer without radiation polymerizability as a base polymer, and uses monomers and oligomers with radiation polymerizability as curable components. In this case, even if the radiation curable resin layer with reduced curable components is cured, the curing becomes insufficient, and the adhesion of the side of the sealing sheet is difficult to reduce, and the adhesion of the side cannot be fully reduced. In addition, the radiation non-curable adhesive layer into which the curable components have invaded undergoes unexpected curing when irradiated with radiation, and the adhesive force is reduced, and the original adhesion cannot be exerted, resulting in poor sealing of the optical semiconductor element.

[0066] In addition, when the optical semiconductor element is sealed by using the optical semiconductor element sealing sheet, the adhesion of the cut part can be suppressed when the optical semiconductor device is cut after being manufactured, and an optical semiconductor device with good appearance can be manufactured. Furthermore, when the conventional radiation-curable resin layer is used, the above-mentioned radiation-polymerizable monomers and oligomers have low compatibility in the radiation-curable resin layer, and the transparency after curing is poor. In contrast, the optical semiconductor element sealing sheet of the present invention has the above-mentioned radiation-curable resin layer, and therefore has excellent transparency after curing.

[0067] The radiation-curable resin layer is preferably a resin layer with adhesiveness, i.e., a radiation-curable adhesive layer. By having such a structure, when the optical semiconductor element is sealed, the optical semiconductor element can be easily buried. In addition, before the radiation is cured, the adhesion to the substrate, the radiation non-curable adhesive layer, and the optical semiconductor element is excellent, and the sealing of the optical semiconductor element is more excellent. As the above-mentioned radiation, active energy rays such as electron beams, ultraviolet rays, α rays, β rays, γ rays, and X-rays can be listed. Among them, ultraviolet rays are preferred.

[0068] The radiation-curable resin layer preferably contains the polymer having radiation-polymerizable functional groups as a base polymer (i.e., the polymer having the highest content ratio). The content ratio of the polymer having radiation-polymerizable functional groups in the radiation-curable resin layer is preferably 50% by mass or more (e.g., 50 to 100% by mass) relative to the total amount 100% by mass of the radiation-curable resin layer, more preferably 80% by mass or more (e.g., 80 to 100% by mass), and further preferably 90% by mass or more (e.g., 90 to 100% by mass). If the above-mentioned content ratio is 50% by mass or more, the curability of the radiation-curable resin layer is better, and the adhesion of the side is further reduced by radiation irradiation. In addition, the transparency of the sheet for sealing optical semiconductor elements is better.

[0069] As the radiation polymerizable functional group, radiation free radical polymerizable groups such as groups containing carbon-carbon unsaturated bonds such as olefinic unsaturated groups, radiation cation polymerizable groups, etc. can be listed. As the group containing carbon-carbon unsaturated bonds, for example, vinyl, propenyl, isopropenyl, acryloyl, methacryloyl, etc. can be listed. As the radiation cation polymerizable group, epoxy, oxetanyl, oxacyclopentyl, etc. can be listed. Among them, preferably a group containing carbon-carbon unsaturated bonds, more preferably acryloyl, methacryloyl. The radiation polymerizable functional group can be only one type, or more than two types. The position of the radiation polymerizable functional group can be any one of the polymer side chain, the polymer main chain, and the end of the polymer main chain.

[0070] The polymer having radiation polymerizable functional groups can be prepared by, for example, reacting a polymer having a reactive functional group (first functional group) with a functional group (second functional group) capable of reacting with the first functional group to form a bond and a compound having the radiation polymerizable functional group while maintaining the radiation polymerizability of the radiation polymerizable functional group. Therefore, the polymer having radiation polymerizable functional groups preferably includes a structural portion derived from the polymer having the first functional group and a structural portion derived from the compound having the second functional group and the radiation polymerizable functional group.

[0071] As the combination of the above-mentioned first functional group and the above-mentioned second functional group, for example, carboxyl and epoxy, epoxy and carboxyl, carboxyl and aziridine, aziridine and carboxyl, hydroxyl and isocyanate, isocyanate and hydroxyl etc. can be listed. Among these, from the viewpoint of the ease of reaction tracking, preferably the combination of hydroxyl and isocyanate, the combination of isocyanate and hydroxyl. The above-mentioned combination can be only one, or it can be two or more.

[0072] Examples of the polymer having the radiation polymerizable functional group, i.e., the polymer having the first functional group include acrylic polymers, urethane acrylate resins, epoxy resins, epoxy acrylate resins, oxetane resins, silicone resins, silicone acrylic resins, polyester resins, etc. Among them, acrylic polymers are preferred. The above polymers may be used alone or in combination of two or more.

[0073] The acrylic polymer is a polymer containing a structural unit derived from an acrylic monomer (a monomer component having a (meth)acryloyl group in a molecule) as a structural unit of the polymer. The acrylic polymer may be used alone or in combination of two or more.

[0074] The acrylic polymer is preferably a polymer containing the largest number of structural units derived from (meth)acrylate in terms of mass ratio. It should be noted that in this specification, "(meth)acrylic acid" means "acrylic acid" and / or "methacrylic acid" (either or both of "acrylic acid" and "methacrylic acid"), and the same applies to other matters.

[0075] Examples of the (meth)acrylate include, for example, hydrocarbon-containing (meth)acrylates optionally having an alkoxy group. Examples of the hydrocarbon-containing (meth)acrylates in the hydrocarbon-containing (meth)acrylates optionally having an alkoxy group include (meth)acrylates having alicyclic hydrocarbon groups such as (meth)alkyl acrylates and (meth)acrylate cycloalkyl esters having a straight-chain or branched aliphatic hydrocarbon group; (meth)acrylates having aromatic hydrocarbon groups such as (meth)aryl acrylates. The hydrocarbon-containing (meth)acrylates optionally having an alkoxy group may be used alone or in combination of two or more.

[0076] 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, amyl (meth)acrylate, isoamyl (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.

[0077] As the alkyl (meth)acrylate, preferably, one 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). When the number of carbon atoms is within the above range, it is easy to adjust the glass transition temperature of the acrylic polymer and to make the adhesion of the radiation-curable resin layer more appropriate.

[0078] Examples of the (meth)acrylate having the alicyclic hydrocarbon group include (meth)acrylate having a monocyclic aliphatic hydrocarbon ring such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate; (meth)acrylate having a dicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; (meth)acrylate having a tricyclic aliphatic hydrocarbon ring such as dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, tricyclopentyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate. Among them, a (meth)acrylate having a monocyclic aliphatic hydrocarbon ring is preferred, and cyclohexyl (meth)acrylate is more preferred.

[0079] As a (meth)acrylate which has the said aromatic hydrocarbon group, phenyl (meth)acrylate, benzyl (meth)acrylate, etc. are mentioned, for example.

[0080] Examples of the hydrocarbon group-containing (meth)acrylate having an alkoxy group include those in which one or more hydrogen atoms in the hydrocarbon group of the above-mentioned hydrocarbon group-containing (meth)acrylate are substituted with an alkoxy group, and examples thereof include 2-methoxymethyl, 2-methoxyethyl, and 2-methoxybutyl (meth)acrylate.

[0081] As the hydrocarbon group-containing (meth)acrylate optionally having an alkoxy group, it is preferred to include an alkyl (meth)acrylate having a linear or branched aliphatic hydrocarbon group, and it is more preferred to include a (meth)acrylate having an alicyclic hydrocarbon group. In this case, the radiation-curable resin layer has a good balance of adhesiveness, and the sealing property of the optical semiconductor element is more excellent.

[0082] In order to appropriately show the basic characteristics such as adhesiveness and adhesion to optical semiconductor elements brought by the above-mentioned hydrocarbon group-containing (meth)acrylate optionally having an alkoxy group in the radiation-curable resin layer, the proportion of the above-mentioned hydrocarbon group-containing (meth)acrylate optionally having an alkoxy group in all the monomer components constituting the above-mentioned acrylic polymer having the first functional group is preferably 40 mol% or more, more preferably 50 mol% or more relative to the total amount (100 mol%) of the above-mentioned all monomer components. In addition, from the viewpoint of being able to copolymerize other monomer components to obtain the effects of the other monomer components, the above-mentioned proportion is preferably 95 mol% or less, more preferably 80 mol% or less.

[0083] The proportion of the (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group in all the monomer components constituting the acrylic polymer having the first functional group is preferably 30 mol% or more, more preferably 40 mol% or more, relative to the total amount (100 mol%) of all the monomer components. In addition, the above proportion is preferably 90 mol% or less, more preferably 70 mol% or less.

[0084] The ratio of the (meth)acrylate having an alicyclic hydrocarbon group in all monomer components constituting the acrylic polymer having the first functional group is preferably 1 mol% or more, more preferably 5 mol% or more, relative to the total amount (100 mol%) of all monomer components. In addition, the ratio is preferably 30 mol% or less, more preferably 20 mol% or less.

[0085] The acrylic polymer may contain structural units derived from other monomer components copolymerizable with the hydrocarbon-containing (meth)acrylate optionally having an alkoxy group for the purpose of introducing the first functional group or modifying cohesion, heat resistance, etc. The other monomer components include, for example, carboxyl-containing monomers, acid anhydride monomers, hydroxyl-containing monomers, glycidyl-containing monomers, sulfonic acid-containing monomers, phosphoric acid-containing monomers, nitrogen-containing monomers, and other polar group-containing monomers. The other monomer components may be used alone or in combination of two or more.

[0086] Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. Examples of the acid anhydride monomer include maleic anhydride, itaconic anhydride, etc.

[0087] Examples of the hydroxyl-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.

[0088] Examples of the glycidyl group-containing monomer include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate.

[0089] 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.

[0090] As said phosphoric acid group-containing monomer, 2-hydroxyethyl acryloyl phosphate etc. are mentioned, for example.

[0091] 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.

[0092] As the above-mentioned polar group-containing monomer constituting the above-mentioned acrylic polymer, it is preferable to include a hydroxyl-containing monomer. By using a hydroxyl-containing monomer, it is easy to introduce the first functional group. In addition, the acrylic polymer and the radiation-curable resin layer have excellent water resistance, and the optical semiconductor element sealing sheet is not easy to fog even when used in an environment with high humidity, and has excellent whitening resistance.

[0093] 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.

[0094] In order to appropriately express the basic characteristics such as adhesiveness and adhesion to optical semiconductor elements brought by the above-mentioned hydrocarbon group-containing (meth)acrylate optionally having an alkoxy group in the radiation-curable resin layer, the proportion of the above-mentioned polar group-containing monomer in the total monomer components (100 mol%) constituting the above-mentioned acrylic polymer having the first functional group is preferably 5 to 50 mol%, more preferably 10 to 40 mol%. In particular, from the viewpoint of excellent water resistance of the radiation-curable resin layer, the proportion of the hydroxyl-containing monomer is preferably within the above range.

[0095] In order to form a cross-linked structure in the polymer skeleton, the acrylic polymer may contain a structural unit derived from a multifunctional (meth)acrylate copolymerizable with the monomer components constituting the acrylic polymer. 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)acrylate may be used alone or in combination of two or more.

[0096] In order to properly exhibit the basic properties such as adhesion and close adhesion to optical semiconductor elements brought about by the above-mentioned hydrocarbon-containing (meth)acrylate optionally having an alkoxy group in the radiation-curable resin layer, the proportion of the above-mentioned multifunctional (meth)acrylate in the total monomer components (100 mol %) constituting the above-mentioned acrylic polymer having the first functional group is preferably 40 mol % or less, more preferably 30 mol % or less.

[0097] As a combination of the above-mentioned first functional group and the above-mentioned second functional group, from the viewpoint of the great technical difficulty in preparing a polymer having an isocyanate group with high reactivity and the ease of preparing and obtaining an acrylic polymer having a hydroxyl group, a preferred combination is that the above-mentioned first functional group is a hydroxyl group and the above-mentioned second functional group is an isocyanate group.

[0098] Examples of the compound having a radiation polymerizable functional group and an isocyanate group include methacryloyl isocyanate, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate (MOI), m-isopropenyl-α,α-dimethylbenzyl isocyanate, etc. These compounds may be used alone or in combination of two or more.

[0099] The content of the structural part derived from the compound having the second functional group and the radiation-polymerizable functional group in the acrylic polymer having the radiation-polymerizable functional group is preferably 0.5 mol or more, more preferably 1 mol or more, further preferably 3 mol or more, further preferably 10 mol or more, relative to 100 mol of the total amount of the structural part derived from the acrylic polymer having the first functional group, from the viewpoint of being able to further promote the curing of the radiation-curable resin layer. The above content is, for example, 100 mol or less.

[0100] The molar ratio of the second functional group to the first functional group in the acrylic polymer having a radiation polymerizable functional group [second functional group / first functional group] is preferably 0.01 or more, more preferably 0.05 or more, further preferably 0.2 or more, and particularly preferably 0.4 or more, from the viewpoint of further promoting the curing of the radiation curable resin layer. In addition, from the viewpoint of further reducing the low molecular weight substances in the radiation curable resin layer, the molar ratio is preferably less than 1.0, and more preferably 0.9 or less.

[0101] The above-mentioned acrylic polymer having a radiation-polymerizable functional group can be prepared by the following method: for example, after polymerizing (copolymerizing) a raw material monomer containing a monomer component having a first functional group to obtain an acrylic polymer having a first functional group, the above-mentioned compound having a second functional group and a radiation-polymerizable functional group is subjected to a condensation reaction or an addition reaction with the acrylic polymer while maintaining the radiation polymerizability of the radiation-polymerizable functional group.

[0102] The acrylic polymer having the first functional group 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 by active energy ray irradiation (active energy ray polymerization). In addition, the obtained acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

[0103] Various common solvents can be used in the polymerization of the monomer components. Examples of the above-mentioned solvents include 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; ketones such as methyl ethyl ketone and methyl isobutyl ketone, and other organic solvents. The above-mentioned solvents may be used alone or in combination of two or more.

[0104] 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 polymer can be controlled by the amount of the polymerization initiator and chain transfer agent used and the reaction conditions, and the amount can be appropriately adjusted according to their types.

[0105] As the polymerization initiator used for the polymerization of the monomer components, a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), etc. can be used depending on the type of the polymerization reaction. The above-mentioned polymerization initiators may be used alone or in combination of two or more.

[0106] The thermal polymerization initiator is not particularly limited, and examples thereof include azo polymerization initiators, peroxide polymerization initiators, redox polymerization initiators, etc. 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 further preferably 0.02 to 0.5 parts by mass, relative to 100 parts by mass of the total amount of all monomer components constituting the acrylic polymer having the first functional group.

[0107] Examples of the photopolymerization initiator include benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, and titanocene photopolymerization initiators. Among them, acetophenone photopolymerization initiators are preferred.

[0108] Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl 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.

[0109] The amount of the photopolymerization initiator used is preferably 0.005 to 1 part by mass, more preferably 0.01 to 0.7 part by mass, and still more preferably 0.18 to 0.5 part by mass, relative to 100 parts by mass of the total amount of all monomer components constituting the acrylic polymer having the first functional group. If the amount is 0.005 part by mass or more (particularly 0.18 part by mass or more), there is a tendency that the molecular weight of the acrylic polymer can be easily controlled to be small, the residual stress of the radiation curable resin layer becomes high, and the height difference absorption becomes better.

[0110] The reaction of the acrylic polymer having the first functional group and the compound having the second functional group and the radiation polymerizable functional group can be carried out by stirring in a solvent in the presence of a catalyst. As the solvent, the above solvents can be listed. The catalyst is appropriately selected according to the combination of the first functional group and the second functional group. The reaction temperature in the reaction is, for example, 5 to 100° C., and the reaction time is, for example, 1 to 36 hours.

[0111] The acrylic polymer having radiation polymerizable functional groups may have a structural part derived from a crosslinking agent. For example, the acrylic polymer may be crosslinked to further reduce the low molecular weight substances in the radiation curable resin layer. In addition, the weight average molecular weight of the acrylic polymer may be increased. It should be noted that the crosslinking agent is a substance that crosslinks functional groups other than the radiation polymerizable functional groups (e.g., first functional groups, second functional groups, or first functional groups and second functional groups). The crosslinking agent may be used alone or in combination of two or more.

[0112] 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, and silane crosslinking agents. Among the crosslinking agents, isocyanate crosslinking agents and epoxy crosslinking agents are preferred, and isocyanate crosslinking agents are more preferred, from the viewpoint of excellent adhesion to optical semiconductor elements and a small amount of impurity ions.

[0113] 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; 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.

[0114] The content of the structural part derived from the above-mentioned 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 further preferably 0.01 to 3 parts by mass, relative to 100 parts by mass of the total amount of the acrylic polymer having a radiation-polymerizable functional group excluding the structural part derived from the above-mentioned cross-linking agent.

[0115] In the above-mentioned radiation curable resin layer, other components other than the above-mentioned polymer with radiation polymerizable functional groups can be included within the scope that does not damage the effect of the present invention. As the above-mentioned other components, crosslinking accelerators, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, antioxidants, fillers (metal powders, organic fillers, inorganic fillers, etc.), colorants (pigments, dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, inhibitors, granular materials, foil-like materials, etc. can be listed. The above-mentioned other components can be used only one, or two or more can be used.

[0116] (Radiation non-curing adhesive layer)

[0117] As the adhesive forming the above-mentioned radiation non-curing adhesive layer, a known and / or commonly used pressure-sensitive adhesive that does not have radiation curing properties, i.e., does not contain a compound having radiation curing properties, can be used. Among them, a small amount of inevitable radiation curing compounds that are transferred and invaded from other stacked layers can be included. As the above-mentioned adhesive, for example, acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, their mixed systems, etc.), silicone adhesives, polyester adhesives, urethane adhesives, polyether adhesives, polyamide adhesives, fluorine adhesives, etc. can be listed. Among them, as the adhesive constituting the radiation non-curing adhesive layer, from the viewpoint of adhesion, weather resistance, cost, and ease of design of the adhesive, acrylic adhesives are preferably used. The above-mentioned radiation non-curing adhesive layer is preferably an acrylic adhesive layer composed of acrylic adhesives. The above-mentioned adhesive can be used only one type, or two or more types can be used.

[0118] The acrylic adhesive layer contains an acrylic polymer as a base polymer. The acrylic polymer is a polymer containing an acrylic monomer as a monomer component constituting the polymer. That is, the acrylic polymer contains a structural unit derived from the acrylic monomer. It should be noted that only one type of acrylic polymer can be used, or two or more types can be used.

[0119] The content of the acrylic polymer in the acrylic adhesive layer is not particularly limited, but is preferably 50% by mass or more (e.g., 50 to 100% by mass), more preferably 80% by mass or more (e.g., 80 to 100% by mass), and even more preferably 90% by mass or more (e.g., 90 to 100% by mass), relative to the total amount of the adhesive layer (100% by mass). If the content is 50% by mass or more, the transparency of the optical semiconductor element sealing sheet is further improved.

[0120] The acrylic polymer is preferably a polymer composed (formed) of an alkyl (meth)acrylate as an essential monomer component. That is, the acrylic polymer preferably contains an alkyl (meth)acrylate as a structural unit.

[0121] Examples of the (meth)acrylate include, for example, a hydrocarbon-containing (meth)acrylate optionally having an alkoxy group. Examples of the hydrocarbon-containing (meth)acrylate in the hydrocarbon-containing (meth)acrylate optionally having an alkoxy group include the above-mentioned (meth)acrylate alkyl esters having a linear or branched aliphatic hydrocarbon group, the above-mentioned (meth)acrylate having an alicyclic hydrocarbon group, the above-mentioned (meth)acrylate having an aromatic hydrocarbon group, and the like. The above-mentioned hydrocarbon-containing (meth)acrylate optionally having an alkoxy group may be used alone or in combination of two or more.

[0122] As the alkyl (meth)acrylate, preferably, one 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). When the number of carbon atoms is within the above range, it is easy to adjust the glass transition temperature of the acrylic polymer and to make the adhesion of the radiation non-curing adhesive layer more appropriate.

[0123] As the (meth)acrylate having an alicyclic hydrocarbon group, among them, a (meth)acrylate having a monocyclic aliphatic hydrocarbon ring is preferred, and cyclohexyl (meth)acrylate is more preferred.

[0124] As the hydrocarbon group-containing (meth)acrylate optionally having an alkoxy group, preferably, a (meth)acrylate alkyl ester having a linear or branched aliphatic hydrocarbon group is included, and more preferably, a (meth)acrylate having an alicyclic hydrocarbon group is included. In this case, the balance of the adhesiveness of the radiation non-curing adhesive layer is good, and the sealing property of the optical semiconductor element is more excellent.

[0125] In order to properly show the basic characteristics such as the adhesiveness brought by the above-mentioned hydrocarbon group-containing (meth) acrylate optionally having an alkoxy group and the close adhesion to the optical semiconductor element in the radiation non-curing adhesive layer, the proportion of the above-mentioned hydrocarbon group-containing (meth) acrylate optionally having an alkoxy group in all the monomer components constituting the above-mentioned acrylic polymer is preferably 40 mol% or more, more preferably 50 mol% or more relative to the total amount (100 mol%) of the above-mentioned all monomer components. In addition, from the viewpoint of being able to copolymerize other monomer components to obtain the effects of the other monomer components, the above-mentioned proportion is preferably 95 mol% or less, more preferably 80 mol% or less.

[0126] The proportion of the (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group in all the monomer components constituting the acrylic polymer is preferably 30 mol% or more, more preferably 40 mol% or more, relative to the total amount (100 mol%) of all the monomer components. In addition, the above proportion is preferably 90 mol% or less, more preferably 70 mol% or less.

[0127] The ratio of the (meth)acrylate having an alicyclic hydrocarbon group in all the monomer components constituting the acrylic polymer is preferably 1 mol% or more, more preferably 5 mol% or more, relative to the total amount (100 mol%) of all the monomer components. In addition, the ratio is preferably 30 mol% or less, more preferably 20 mol% or less.

[0128] The acrylic polymer may contain a structural unit derived from other monomer components such as the polar group-containing monomer for the purpose of improving cohesive force, heat resistance, etc. The other monomer components may be used alone or in combination of two or more.

[0129] The polar group-containing monomer constituting the acrylic polymer preferably includes a hydroxyl group-containing monomer. In this case, the acrylic polymer and the radiation non-curing adhesive layer have excellent water resistance, and the optical semiconductor element sealing sheet is not prone to fogging even when used in a high humidity environment and has excellent whitening resistance.

[0130] 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.

[0131] In order to appropriately express the basic characteristics such as the adhesiveness brought by the (meth)acrylate containing a hydrocarbon group which may have an alkoxy group and the adhesion to the optical semiconductor element in the radiation non-curing adhesive layer, the proportion of the above-mentioned polar group-containing monomer in the total monomer components (100 mol%) constituting the above-mentioned acrylic polymer is preferably 5 to 50 mol%, more preferably 10 to 40 mol%. In particular, from the viewpoint of making the radiation non-curing adhesive layer more excellent in water resistance, the proportion of the hydroxyl-containing monomer is preferably within the above range.

[0132] In order to form a cross-linked structure in the polymer skeleton, the acrylic polymer may contain a structural unit derived from a multifunctional monomer copolymerizable with the monomer components constituting the acrylic polymer. As the multifunctional monomer, in addition to the multifunctional (meth)acrylate, monomers having a (meth)acryloyl group and other reactive functional groups in the molecule such as (meth)acrylate epoxy esters (e.g., (meth)acrylate polyglycidyl ester), polyester (meth)acrylate, and urethane (meth)acrylate may be cited. The multifunctional monomer may be used alone or in combination of two or more.

[0133] In order to properly exhibit the basic properties such as adhesion brought by the above-mentioned hydrocarbon-containing (meth)acrylate optionally having an alkoxy group and close adhesion to optical semiconductor elements in the radiation non-curing adhesive layer, the proportion of the above-mentioned multifunctional monomer in the total monomer components (100 mol%) constituting the above-mentioned acrylic polymer is preferably 40 mol% or less, more preferably 30 mol% or less.

[0134] The acrylic polymer may have a structural part derived from the crosslinking agent. For example, the acrylic polymer may be crosslinked to further reduce the low molecular weight substances in the radiation curable resin layer. In addition, the weight average molecular weight of the acrylic polymer may be increased. The crosslinking agent may be used alone or in combination of two or more.

[0135] The acrylic polymer can be produced by the same method as that for the acrylic polymer having the first functional group.

[0136] The weight average molecular weight of the acrylic polymer is not particularly limited, but is preferably 100,000 to 3,000,000, and more preferably 200,000 to 2,500,000. If the weight average molecular weight is within the above range, the adhesiveness of the radiation non-curing adhesive layer is well balanced, and the sealing of the optical semiconductor element is more excellent. It should be noted that the weight average molecular weight refers to a value measured by gel permeation chromatography (GPC) and calculated based on polystyrene conversion.

[0137] The radiation non-curable adhesive layer may contain other components other than the base polymer within the range that does not impair the effect of the present invention. As the other components, the components exemplified and described as other components that may be contained in the radiation curable resin layer may be cited. The other components may be used alone or in combination of two or more.

[0138] (Seal part)

[0139] In the sealing portion, the radiation non-curing adhesive layer and the radiation curing resin layer are laminated. The radiation non-curing adhesive layer and the radiation curing resin layer may be laminated directly without the aid of other layers, or may be laminated with the aid of other layers. Even in the case where the sealing portion has a structure in which the radiation non-curing adhesive layer and the radiation curing resin layer are directly laminated, the polymer having a radiation polymerizable functional group in the radiation curing resin layer is difficult to transfer to the radiation non-curing adhesive layer. Therefore, the optical semiconductor element of the optical semiconductor element sealing sheet of the present invention has excellent sealing properties and suppresses side adhesion after curing.

[0140] The radiation non-curing adhesive layer and the radiation curing resin layer may be a single layer, or may be a plurality of layers of the same or different compositions, thicknesses, etc. When the sealing portion has a plurality of at least one of the radiation non-curing adhesive layer and the radiation curing resin layer, the plurality of layers may be stacked continuously or with other layers interposed therebetween.

[0141] The sealing layer preferably has the radiation non-curing adhesive layer on the surface of the sealing portion that becomes the optical semiconductor element side when the optical semiconductor element is sealed. Specifically, the radiation non-curing adhesive layer is preferably located on the surface of the optical semiconductor element sealing sheet that becomes the optical semiconductor element side when the optical semiconductor element is sealed (the surface of the sheet from which the release liner is removed when a release liner is provided). When the radiation non-curing adhesive layer is located on the surface, when the optical semiconductor element is sealed with the optical semiconductor element sealing sheet, the optical semiconductor element and the substrate that are directly in close contact with the radiation non-curing adhesive layer have excellent sealing properties for the optical semiconductor element.

[0142] The radiation-curable resin layer is preferably thicker than the radiation-non-curable adhesive layer. By having such a structure, the low adhesion of the radiation-curable resin layer in the adjacent optical semiconductor device after curing prevails over the high adhesion of the radiation-non-curable adhesive layers in the adjacent optical semiconductor devices in a flat state. Therefore, the adhesion between the sealing parts is lower, making it less likely for the sheet to be damaged or the sheet of the adjacent optical semiconductor device to be attached when the adjacent optical semiconductor devices are separated from each other. In addition, when the optical semiconductor device is manufactured by sealing the optical semiconductor element with the optical semiconductor element sealing sheet and then cutting it, the adhesion of the cut part can be further suppressed, and an optical semiconductor device with a good appearance can be manufactured. It should be noted that when there are multiple radiation-curable resin layers and radiation-non-curable adhesive layers, the thickness is the total thickness (total thickness) of the multiple layers.

[0143] The thickness (total thickness) of the radiation-curable resin layer is preferably the thickest among all the layers constituting the optical semiconductor element sealing sheet. In particular, the optical semiconductor element sealing sheet preferably has a radiation-curable resin layer having a thickness of 1 layer that is the thickest among all the layers constituting the optical semiconductor element sealing sheet. It should be noted that a layer obtained by directly stacking multiple layers of the same composition is regarded as 1 layer. In addition, when there are more than two thickest layers, any layer is equivalent to the thickest layer.

[0144] For example, in Figure 1 In the optical semiconductor element sealing sheet 1 shown, the sealing portion 3 is composed of a radiation curing resin layer 31 and a radiation non-curing adhesive layer 32. The radiation curing resin layer 31 is located on the substrate portion 2 side in the sealing portion 3. The radiation non-curing adhesive layer 32 is located on the optical semiconductor element side surface in the sealing portion 3, and is located on the surface of the optical semiconductor element sealing sheet 1 on the opposite side to the substrate portion 2 after removing the release liner 4. The radiation curing resin layer 31 is thicker than the radiation non-curing adhesive layer 32 and is the thickest layer in the sealing portion 3 and in the optical semiconductor element sealing sheet 1.

[0145] The thickness (total thickness) of the radiation curable resin layer is preferably 20 to 800 μm, more preferably 30 to 700 μm, and even more preferably 50 to 600 μm. If the thickness is 20 μm or more, it is less likely to cause sheet damage or adhesion of sheets of adjacent optical semiconductor devices when adjacent optical semiconductor devices are separated from each other. If the thickness is 800 μm or less, the thickness of the sealing portion can be reduced, and the optical semiconductor device can be further thinned.

[0146] The thickness (total thickness) of the radiation curable resin layer is preferably 5 to 90%, more preferably 10 to 85%, and further preferably 40 to 80% relative to 100% of the total thickness of the optical semiconductor element sealing sheet (excluding the release liner and the surface protection film). If the above ratio is 5% or more, it is less likely to cause sheet damage and adhesion of the adjacent optical semiconductor device sheet when the adjacent optical semiconductor devices are separated from each other. If the above thickness is 90% or less, the thickness of the sealing portion can be reduced, and the optical semiconductor device can be further thinned.

[0147] The hardness of the radiation-curable resin layer at a layer cross section at a temperature of 23° C. based on the nanoindentation method after curing is preferably 1.2 MPa or more, more preferably 1.4 MPa or more, further preferably 2.0 MPa or more, further preferably 15.0 MPa or more, and particularly preferably 50.0 MPa or more. The hardness based on the nanoindentation method is obtained as follows: the load and indentation depth of the indenter when the indenter is pressed into the surface of the object are continuously measured under load and unload, and the hardness is obtained from the obtained load-indentation depth curve. If the hardness is 1.2 MPa or more, the radiation-curable resin layer has a moderate hardness after curing, so that when adjacent optical semiconductor devices are separated from each other in a flat state, it is less likely to cause sheet defects and sheets of adjacent optical semiconductor devices to adhere.

[0148] The hardness of the radiation-curable resin layer at a layer cross section at a temperature of 23° C. based on a nanoindentation method before curing is preferably less than 1.4 MPa, more preferably 1.3 MPa or less, and further preferably 1.2 MPa or less. If the hardness is less than 1.4 MPa, the radiation-curable resin layer is relatively soft before curing, and the sealing property when sealing the optical semiconductor element is better.

[0149] The ratio of the hardness of the radiation-curable resin layer at a layer cross section at a temperature of 23° C. based on the nanoindentation method after curing to that before curing [after curing / before curing] is preferably 1.0 or more, more preferably 1.3 or more, further preferably 5.0 or more, and particularly preferably 10.0 or more. If the above ratio is 1.3 or more, the sealing property of the optical semiconductor element in the sealing portion is more excellent before curing of the radiation-curable resin layer, and the sticking of the side surface is further suppressed after curing.

[0150] The arithmetic mean height Sa of the cross section in the thickness direction after curing of the radiation curable resin layer is preferably 85 μm or less, more preferably 70 μm or less, further preferably 40 μm or less, further preferably 10 μm or less, further preferably 4 μm or less, and particularly preferably 1 μm or less. If the arithmetic mean height Sa is 85 μm or less, the surface roughness of the exposed radiation curable resin layer after curing, i.e., the side surface of the cured sealing layer is small, and when adjacent optical semiconductor devices are separated from each other, it is less likely to cause chipping of the sheet and adhesion of the sheet of the adjacent optical semiconductor device.

[0151] The thickness of the radiation non-curing adhesive layer located on the surface of the optical semiconductor element sealing sheet (i.e., the surface of the sealing portion) is preferably 1 μm or more, more preferably 4 μm or more, and further preferably 15 μm or more. If the thickness is 1 μm or more, the optical semiconductor element sealing sheet has better adhesion to the optical semiconductor element and the substrate. The thickness is preferably 500 μm or less, more preferably 300 μm or less, and further preferably 200 μm or less. If the thickness is 500 μm or less, when adjacent optical semiconductor devices are separated from each other, it is less likely to cause sheet defects and adhesion of sheets of adjacent optical semiconductor devices. In addition, when cutting the optical semiconductor device, the adhesion of the cut portion can be further suppressed, and an optical semiconductor device with good appearance can be produced.

[0152] The sealing part may have other layers in addition to the radiation curable resin layer and the radiation non-curable adhesive layer. The ratio of the total thickness of the radiation curable resin layer and the radiation non-curable adhesive layer to the thickness of the sealing part (100%) is preferably 70% or more, more preferably 80% or more, further preferably 90% or more, and particularly preferably 96% or more.

[0153] The sealing portion may include a layer containing a colorant. With such a configuration, when the optical semiconductor device is laid flat and applied to a display, it is possible to suppress the color mixing of light emitted by each optical semiconductor element when the optical semiconductor device is used, and it is possible to adjust the appearance of the display when the optical semiconductor device is not used. The layer containing a colorant may have only one layer, or may have two or more layers.

[0154] The above-mentioned layer containing the colorant can be the above-mentioned radiation-curable resin layer, the above-mentioned radiation-non-curable adhesive layer and other layers other than them. Preferably, the above-mentioned radiation-curable resin layer and / or the above-mentioned radiation-non-curable adhesive layer is a layer containing a colorant, and more preferably, the above-mentioned radiation-non-curable adhesive layer is a layer containing a colorant.

[0155] As the above-mentioned colorant, a black colorant is preferably used. As the above-mentioned black colorant, a known and / or commonly used colorant (pigment, dye, etc.) for presenting black can be used, and examples thereof include carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, ink stick, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complex, anthraquinone colorant, zirconium nitride, etc. The black colorant can be used alone or in combination. In addition, a colorant that combines and mixes colorants presenting colors other than black and functions as a black colorant can also be used.

[0156] <Base Material>

[0157] The substrate portion serves as a support for the sealing portion, and the optical semiconductor element sealing sheet has excellent handling properties due to the substrate portion. The substrate portion may be a single layer, or may be a plurality of layers that are the same or have different compositions, thicknesses, etc. When the substrate portion is a plurality of layers, each layer may be bonded together with other layers such as an adhesive layer. It should be noted that the substrate layer used in the substrate portion is a portion that is attached to a substrate having an optical semiconductor element together with the sealing portion when the optical semiconductor element sealing sheet is used to seal the optical semiconductor element, and the release liner that is peeled off when the optical semiconductor element sealing sheet is used (when attached), except that the surface protection film used to protect the surface of the substrate portion is not included in the "substrate portion".

[0158] As the substrate layer constituting the above-mentioned substrate portion, for example, glass, plastic substrate (especially plastic film) etc. can be listed. As the resin constituting the above-mentioned plastic substrate, for example, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolymer polypropylene, polybutene, polymethylpentene, ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate (random, alternating) copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-propylene copolymer, cyclic olefin polymer, ethylene-butene copolymer, ethylene-hexene copolymer can be listed. Polyolefin resins such as polyols; polyurethanes; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT); polycarbonates; polyimide resins; polyetheretherketone; polyetherimide; polyamides such as aramid and wholly aromatic polyamide; polyphenylene sulfide; fluororesins; polyvinyl chloride; polyvinylidene chloride; cellulose resins such as triacetate cellulose (TAC); silicone resins; acrylic resins such as polymethyl methacrylate (PMMA); polysulfones; polyarylates; polyvinyl acetate, etc. The above resins may be used alone or in combination of two or more.

[0159] The substrate layer may be various optical films such as an anti-reflection (AR) film, a polarizing plate, a phase difference plate, etc. When the substrate portion has an optical film, the optical semiconductor element sealing sheet may be directly applied to an optical component.

[0160] The plastic film preferably contains a polyester resin and / or a polyimide resin as a main component (the component with the highest mass ratio among the constituent resins). With such a structure, the optical semiconductor element sealing sheet has excellent heat resistance, can suppress the thermal expansion of the optical semiconductor element sealing sheet under high temperature environment, and improves dimensional stability. In addition, it can impart rigidity as a sheet, thereby improving handling and retention.

[0161] The thickness of the plastic film is preferably 20 to 200 μm, more preferably 40 to 150 μm. If the thickness is 20 μm or more, the support and handling properties of the optical semiconductor element sealing sheet are further improved. If the thickness is 200 μm or less, the thickness of the optical semiconductor element sealing sheet can be reduced, and the optical semiconductor device can be further thinned.

[0162] The substrate part preferably comprises a plastic film and an optical film with polyester resin and / or polyimide resin as main components. Optical films such as polarizing plates usually have a tendency to have poor support and handling properties, and by using them in combination with the plastic film, the advantages of both can be brought into play. In this case, in the substrate part, the plastic film is particularly preferably on the sealing part side.

[0163] The substrate portion preferably has an anti-glare and / or anti-reflection layer. The anti-glare and / or anti-reflection layer is obtained, for example, in the form of the anti-glare treatment layer or the anti-reflection treatment layer by subjecting at least one surface of the substrate layer to an anti-glare treatment and / or anti-reflection treatment. The anti-glare treatment layer and the anti-reflection treatment layer may be the same layer or different layers. The anti-glare treatment and the anti-reflection treatment may be implemented using known and / or customary methods, respectively.

[0164] For the purpose of improving the adhesion and retention of the sealing part, the surface of the side of the substrate with the sealing part may be subjected to physical treatments such as corona discharge treatment, plasma treatment, sand pad processing treatment, ozone exposure treatment, flame exposure treatment, high voltage electric shock exposure treatment, ionizing radiation treatment, etc.; chemical treatments such as chromic acid treatment; and surface treatments such as easy adhesion treatment by a coating agent (primer). Preferably, the entire surface of the sealing part side of the substrate is subjected to a surface treatment for improving adhesion.

[0165] exist Figure 1In the optical semiconductor element sealing sheet 1 shown, the base portion 2 is a multilayer having an optical film 21 and a plastic film 23, and the optical film 21 and the plastic film 23 are bonded via an adhesive layer 22. In addition, the surface of the optical film 21 facing the plastic film 23 is subjected to anti-glare treatment and anti-reflection treatment.

[0166] From the viewpoint of excellent function as a support and surface scratch resistance, the thickness of the substrate is preferably 5 μm or more, more preferably 10 μm or more, and from the viewpoint of better transparency, the thickness of the substrate is preferably 300 μm or less, more preferably 200 μm or less.

[0167] <Release liner>

[0168] The release liner is an element for covering and protecting the surface of the sealing portion, and is peeled off from the sheet when the optical semiconductor element sealing sheet is bonded to a substrate on which an optical semiconductor element is arranged.

[0169] Examples of the release liner include polyethylene terephthalate (PET) films, polyethylene films, polypropylene films, plastic films surface-coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent, and paper.

[0170] The thickness of the release liner is, for example, 10 to 200 μm, preferably 15 to 150 μm, and more preferably 20 to 100 μm. If the thickness is 10 μm or more, the release liner is not easily broken by cutting during processing. If the thickness is 200 μm or less, it is easier to peel off the release liner from the sealing portion during use.

[0171] <Sheet for sealing optical semiconductor elements>

[0172] The ratio of the total thickness of the substrate and the sealing portion in the optical semiconductor element sealing sheet is preferably 80% or more, more preferably 90% or more, relative to the thickness of the optical semiconductor element sealing sheet (excluding the release liner and the surface protection film) of 100%. In addition, the ratio of the thickness from the surface of the substrate to the surface of the sealing portion, including the substrate and the sealing portion, is preferably within the above range.

[0173] The total thickness of the substrate and the sealing portion in the optical semiconductor element sealing sheet is preferably 100 to 900 μm, more preferably 200 to 800 μm. The thickness from the substrate surface to the sealing surface including the substrate and the sealing portion is preferably within the above range.

[0174] One embodiment of the method for producing a sheet for encapsulating an optical semiconductor element of the present invention will be described. Figure 1 The optical semiconductor element sealing sheet 1 shown can be produced by the following method. First, a radiation curable resin layer 31 is formed on the plastic film 23 constituting the substrate portion 2. The radiation curable resin layer 31 can be produced as follows: after a resin composition forming the radiation curable resin layer 31 is applied to one surface of the plastic film 23 to form a resin composition layer, desolvation by heating, thermal curing, or other curing other than radiation irradiation is performed to cure the resin composition layer. When the thickness of the radiation curable resin layer 31 is increased, a radiation curable resin layer similarly produced on the release treatment surface of the release liner can be overlapped on the radiation curable resin layer formed on the plastic film 23 and laminated.

[0175] The resin composition forming the radiation curable resin layer can be in any form as long as it does not damage the radiation polymerizability of the radiation polymerizable functional group. For example, the adhesive composition can be an emulsion type, a solvent type (solution type), a hot melt type (hot melt type), etc. Among them, from the viewpoint of easily obtaining an adhesive layer with excellent productivity, a solvent type is preferred.

[0176] In addition to the polymer having radiation polymerizable functional groups and the other components, the resin composition may also contain the crosslinking agent and the photopolymerization initiator (photoinitiator). When the crosslinking agent is contained, when the resin composition layer is heated to form a radiation curable resin layer, crosslinking is performed with the aid of the crosslinking agent. In addition, when the photopolymerization initiator is contained, when the radiation curable resin layer is cured, the polymerization of the radiation polymerizable functional groups can be promoted. The crosslinking agent and the photopolymerization initiator may be used alone or in combination of two or more.

[0177] On the other hand, a radiation non-curing adhesive layer 32 is formed on the peeling treatment surface of the peeling liner 4 prepared separately. The above-mentioned radiation non-curing adhesive layer 32 can be made as follows: after the adhesive composition forming the radiation non-curing adhesive layer 32 is coated on the peeling treatment surface of the peeling liner 4 to form an adhesive composition layer, desolventizing and curing are carried out by heating to cure the adhesive composition layer. Then, the above-mentioned radiation non-curing adhesive layer is stacked on the above-mentioned radiation curing resin layer. In this way, a laminate having the structure of [plastic film 23 / radiation curing resin layer 31 / radiation non-curing adhesive layer 32 / peeling liner 4] is obtained.

[0178] The adhesive composition forming the above-mentioned radiation non-curable adhesive layer can be in any form. For example, the adhesive composition can be an emulsion type, a solvent type (solution type), an active energy ray curable type, a hot melt type (hot melt type), etc. Among them, from the viewpoint of easily obtaining an adhesive layer with excellent productivity, a solvent type or an active energy ray curable adhesive composition is preferably used.

[0179] On the other hand, a laminate of the optical film 21 and the adhesive layer 22 is prepared. Specifically, for example, the adhesive layer 22 can be formed on the release-treated surface of a separately prepared release liner in the same manner as the radiation non-curing adhesive layer 32, and then the optical film 21 is bonded to the adhesive layer 22. Then, the release liner is peeled off to expose the adhesive layer 22, and the laminate is bonded to the surface of the plastic film 23 of the laminate on which the radiation curing resin layer 31 is not formed. As a coating method for the above-mentioned resin composition and adhesive composition, for example, a known and / or customary coating method can be adopted, and examples thereof include roller coating, screen coating, gravure coating, and the like. In addition, the lamination of various layers can be performed using a known roller or laminator. In this way, a laminate can be produced. Figure 1 The optical semiconductor element sealing sheet 1 is shown.

[0180] It should be noted that the optical semiconductor element sealing sheet of the present invention is not limited to the above method. When the substrate portion is composed of multiple layers, the substrate portion can be first prepared, and the radiation-curable resin layer and the radiation-non-curable adhesive layer can be appropriately combined and sequentially stacked on the substrate portion to thereby prepare it.

[0181] By using the optical semiconductor device sealing sheet of the present invention, the sealing portion of the optical semiconductor device sealing sheet of the present invention is bonded to the substrate on which the optical semiconductor element is arranged, and the optical semiconductor element is sealed by the sealing portion, thereby obtaining an optical semiconductor device. Specifically, first, the release liner is peeled off from the optical semiconductor element sealing sheet of the present invention to expose the sealing portion. Then, the exposed surface of the optical semiconductor element sealing sheet of the present invention, i.e., the sealing portion surface, is bonded to the substrate surface on which the optical semiconductor element is arranged of an optical component having a substrate and an optical semiconductor element (preferably a plurality of optical semiconductor elements) arranged on the above-mentioned substrate. When the above-mentioned optical component has a plurality of optical semiconductor elements, the sealing portion is further configured in a manner that fills the gaps between the plurality of optical semiconductor elements, and the plurality of optical semiconductor elements are sealed together. In this way, the optical semiconductor element can be sealed using the optical semiconductor device sealing sheet of the present invention. In addition, by using the optical semiconductor device sealing sheet of the present invention, the optical semiconductor element can also be sealed under a reduced pressure environment or by bonding while applying pressure. Examples of such methods include methods disclosed in Japanese Patent Application Laid-Open Nos. 2016-29689 and 6-97268.

[0182] [Optical semiconductor device]

[0183] The optical semiconductor device can be manufactured using the optical semiconductor element sealing sheet of the present invention. The optical semiconductor device manufactured using the optical semiconductor element sealing sheet of the present invention comprises: a substrate, an optical semiconductor element arranged on the above substrate, and a cured product obtained by curing the optical semiconductor element sealing sheet of the present invention that seals the above optical semiconductor element. The above-mentioned cured product is a cured product obtained by curing the optical semiconductor element sealing sheet of the present invention by irradiation with radiation. Specifically, the radiation-curable resin layer in the optical semiconductor element sealing sheet of the present invention comprises a cured sealing layer obtained by curing by irradiation with radiation.

[0184] 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.

[0185] In the above-mentioned optical semiconductor device, the optical semiconductor element sealing sheet of the present invention has excellent followability to projections and recesses when the optical semiconductor element is used as a projection and the gaps between the plurality of optical semiconductor elements are used as a recess, and has excellent embedding properties of the optical semiconductor element. Therefore, it is preferred to seal a plurality of optical semiconductor elements at once.

[0186] Figure 2 Shown in the use Figure 1 One embodiment of an optical semiconductor device obtained by using the optical semiconductor element sealing sheet 1 shown. Figure 2 The optical semiconductor device 10 shown includes a substrate 5, a plurality of optical semiconductor elements 6 arranged on one surface of the substrate 5, and a cured product 1' of an optical semiconductor element sealing sheet that seals the optical semiconductor elements 6. A cured sealing layer 31' is formed in the cured product 1' of the optical semiconductor element sealing sheet, and the cured sealing layer 31' is formed by peeling off the release liner 4 from the optical semiconductor element sealing sheet 1 and curing the radiation curable resin layer 31 by radiation irradiation. The plurality of optical semiconductor elements 6 are sealed together by the sealing portion. The radiation non-curing adhesive layer 32 in the sealing portion follows the concave-convex shape formed by the plurality of optical semiconductor elements 6, and is closely attached to the optical semiconductor elements 6 and the substrate 5, so as to bury the optical semiconductor elements 6.

[0187] It should be noted that Figure 2In the optical semiconductor device 10 shown, the optical semiconductor element 6 is completely buried in the radiation non-curing adhesive layer 32 and sealed, and is indirectly sealed by the cured sealing layer 31'. The above optical semiconductor device is not limited to this method, and may be a method in which a part of the optical semiconductor element 6 protrudes from the radiation non-curing adhesive layer 32, and the part is buried in the cured sealing layer 31', and the optical semiconductor element 6 is completely buried and sealed by the radiation non-curing adhesive layer 32 and the cured sealing layer 31'.

[0188] As described above, the optical semiconductor device seals the optical semiconductor element using the radiation non-curing adhesive layer and the cured sealing layer which is a cured product of the radiation curing resin layer. Therefore, the optical semiconductor element is closely attached to the sealing portion, the sealing property of the optical semiconductor element is excellent, and the adhesiveness of the side of the cured sealing layer is low, so when the adjacent optical semiconductor devices are separated from each other in a flat state, they can be easily separated, and it is not easy to cause the chip to be damaged or the chip of the adjacent optical semiconductor device to adhere.

[0189] The optical semiconductor device may be a device in which each optical semiconductor device is tiled. That is, the optical semiconductor device may be a device in which a plurality of optical semiconductor devices are arranged in a tile shape along a planar direction.

[0190] Figure 3 1 shows one embodiment of an optical semiconductor device produced by arranging a plurality of optical semiconductor devices. Figure 3 The optical semiconductor device 20 shown is a plurality of optical semiconductor devices 10, 4 in the longitudinal direction and 4 in the transverse direction, for a total of 16, arranged (laid) in a tile shape along a plane direction. The optical semiconductor devices 10 are adjacent to each other at a boundary 20a between two adjacent optical semiconductor devices 10, but they can be easily separated, and it is not easy to cause a defect on the side of the sealing portion, and it is not easy for the resin defected on the side of the sealing portion to adhere from one adjacent optical semiconductor device to another.

[0191] The above-mentioned optical semiconductor device is preferably a backlight of a liquid crystal screen, and is particularly preferably a full direct-lit backlight. In addition, an image display device can be made by combining the above-mentioned backlight with a display panel. When the above-mentioned optical semiconductor device is a backlight of a liquid crystal screen, the optical semiconductor element is an LED element. For example, in the above-mentioned backlight, a metal wiring layer for transmitting a light-emitting control signal to each LED element is stacked on the above-mentioned substrate. Each LED element that emits light of various colors of red (R), green (G), and blue (B) is alternately arranged on the substrate of the display panel via a metal wiring layer. The metal wiring layer is formed of a metal such as copper, which reflects the light emitted by each LED element, reducing the visibility of the image. In addition, the light emitted by each LED element of each color of RGB is mixed, and the contrast is reduced.

[0192] In addition, the above-mentioned optical semiconductor device is preferably a self-luminous display device. In addition, an image display device can be made by combining the above-mentioned self-luminous display device with a display panel as needed. When the above-mentioned optical semiconductor device is a self-luminous display device, the optical semiconductor element is an LED element. As the above-mentioned self-luminous display device, an organic electroluminescent (organic EL) display device and the like can be listed. For example, in the above-mentioned self-luminous display device, a metal wiring layer for transmitting a light control signal to each LED element is stacked on the above-mentioned substrate. Each LED element that emits light of various colors of red (R), green (G), and blue (B) is alternately arranged on the substrate with a metal wiring layer between them. The metal wiring layer is formed of a metal such as copper, which adjusts the light emission degree of each LED element to display various colors.

[0193] The optical semiconductor element sealing sheet of the present invention can be used in an optical semiconductor device that is used in a foldable manner, such as an optical semiconductor device having a bendable image display device (flexible display) (especially a foldable image display device (foldable display)). Specifically, it can be used in a foldable backlight and a foldable self-luminous display device.

[0194] The optical semiconductor element sealing sheet of the present invention is excellent in embedding properties of optical semiconductor elements, and therefore can be preferably used in both the case where the optical semiconductor device is a mini LED display device and a case where the optical semiconductor device is a micro LED display device.

[0195] [Method for manufacturing optical semiconductor device]

[0196] The optical semiconductor device can be manufactured by, for example, a manufacturing method including at least a cutting step, wherein a laminate is cut to obtain an optical semiconductor device, wherein the laminate includes: a substrate, an optical semiconductor element disposed on the substrate, and a cured product obtained by curing the radiation-curable resin layer of the optical semiconductor element sealing sheet of the present invention that seals the optical semiconductor element. The cured product is a cured product obtained by curing the optical semiconductor element sealing sheet of the present invention by radiation irradiation, and specifically, a cured sealing layer obtained by curing the radiation-curable resin layer in the optical semiconductor element sealing sheet of the present invention by radiation irradiation.

[0197] When the radiation-curable resin layer is cured by radiation irradiation, the curing is hindered at the side where oxygen exists, and the curing tends to become insufficient. In contrast, according to the above-mentioned manufacturing method having the above-mentioned cutting step, for a cured product having a sheet for sealing an optical semiconductor element and the cured product includes a laminated body of a cured sealing layer obtained by curing the above-mentioned radiation-curable resin layer by radiation irradiation, the side end portions that are insufficiently cured are removed by cutting off in the above-mentioned cutting step, thereby obtaining an optical semiconductor device in which the side surface is exposed to a region where the adhesion is reduced and the cured product is fully cured. The adhesion of the side surface of the radiation-curable resin layer of the optical semiconductor device manufactured in this way is sufficiently reduced, so that when adjacent optical semiconductor devices are separated from each other in a flat state, it is not easy to cause the sheet to be damaged or the sheet of the adjacent optical semiconductor device to adhere.

[0198] The above-mentioned manufacturing method may further include the following radiation irradiation step: irradiating the stack with radiation to cure the above-mentioned radiation-curable resin layer to obtain the above-mentioned cured product, wherein the stack includes: the above-mentioned substrate, the optical semiconductor element arranged on the above-mentioned substrate, and the above-mentioned optical semiconductor element sealing sheet that seals the above-mentioned optical semiconductor element.

[0199] The manufacturing method may include, before the radiation irradiation step, a sealing step of bonding the optical semiconductor element sealing sheet to the optical semiconductor element provided on the substrate, and sealing the optical semiconductor element with the sealing portion.

[0200] In addition, the manufacturing method may further include a tiling step of arranging the plurality of optical semiconductor devices obtained in the dicing step so as to be in contact with each other along a planar direction. Figure 2 The optical semiconductor device 10 and Figure 3 A method for manufacturing the optical semiconductor device 20 shown will be described.

[0201] (Sealing process)

[0202] In the sealing step, the optical semiconductor element sealing sheet of the present invention is attached to a substrate on which an optical semiconductor element is arranged, and the optical semiconductor element is sealed by the sealing portion. Figure 4 As shown in FIG. 1 , the radiation non-curing adhesive layer 32 of the optical semiconductor element sealing sheet 1 after peeling off the release liner 4 is arranged opposite to the surface of the substrate 5 on which the optical semiconductor element 6 is arranged, so that 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, as shown in FIG. Figure 5 As shown in FIG. 1 , the optical semiconductor element 6 is embedded in the sealing portion 3. Figure 4 As shown, the substrate 5 used in the bonding is Figure 2The substrate 5 in the optical semiconductor device 10 shown is expanded more in the planar direction than that in the optical semiconductor device 10, and the optical semiconductor element 6 is not arranged near the end of the substrate 5. In addition, the optical semiconductor element sealing sheet 1 to be bonded is expanded more in the planar direction than the substrate 5 used in the bonding. That is, the area of ​​the surface of the optical semiconductor element sealing sheet 1 bonded in the sealing process that is opposite to the substrate 5 is larger than the area of ​​the surface of the substrate 5 bonded in the sealing process that is opposite to the optical semiconductor element sealing sheet 1. This is because: the area used for the optical semiconductor device in the stack of the optical semiconductor element sealing sheet 1 and the substrate 5 is fully cured in the subsequent radiation irradiation process, and the ends of the optical semiconductor element sealing sheet 1 and the substrate 5 where there is a possibility of insufficient curing will be cut and removed in the subsequent cutting process.

[0203] The temperature during the above-mentioned lamination is, for example, in the range of room temperature to 110°C. In addition, decompression or pressurization may be performed during the above-mentioned lamination. By decompression and pressurization, the formation of gaps between the sealing portion and the substrate or the optical semiconductor element can be suppressed. In addition, in the above-mentioned sealing step, it is preferred to laminate the optical semiconductor element sealing sheet under reduced pressure and then pressurize it. The pressure during decompression is, for example, 1 to 100 Pa, and the decompression time is, for example, 5 to 600 seconds. In addition, the pressure during pressurization is, for example, 0.05 to 0.5 MPa, and the decompression time is, for example, 5 to 600 seconds.

[0204] (Radiation irradiation process)

[0205] In the radiation irradiation step, a laminated body (e.g., the laminated body obtained in the sealing step) obtained by laminating the optical semiconductor element sealing sheet on the substrate on which the optical semiconductor element is arranged is irradiated with radiation to cure the radiation curable resin layer. Specifically, in the radiation irradiation step, Figure 6 As shown in the figure, the radiation curable resin layer 31 is cured to form a cured sealing layer 31', and a cured product 1' of the optical semiconductor element sealing sheet 1 is obtained. As the above-mentioned radiation, electron beams, ultraviolet rays, α rays, β rays, γ rays, X-rays, etc. can be listed. Among them, ultraviolet rays are preferred. The temperature when irradiating the radiation is, for example, in the range of room temperature to 100°C, and the irradiation time is, for example, 1 minute to 1 hour.

[0206] (Cutting process)

[0207] In the above-mentioned cutting step, a stacked body (for example, a stacked body after the above-mentioned radiation irradiation step) is cut, and the stacked body includes a substrate, an optical semiconductor element arranged on the above-mentioned substrate, and a cured product of the optical semiconductor element sealing sheet of the present invention that seals the above-mentioned optical semiconductor element. Here, in the stacked body provided for the cutting step, the cured product 1' of the optical semiconductor element sealing sheet and the substrate 5 are larger in the planar direction than the optical semiconductor device 10 finally obtained as described above. And, in the above-mentioned cutting step, the cured product of the optical semiconductor element sealing sheet and the side end portions of the substrate are cut and removed. Specifically, in Figure 7 The cutting is performed at the position of the dotted line shown in the figure to remove the side end. The cutting can be performed by a known and / or conventional method, such as using a cutting blade or laser irradiation. In this way, it is possible to produce, for example, Figure 2 An optical semiconductor device 10 is shown.

[0208] Here, it is important in the above-mentioned manufacturing method that the cutting is performed in a state where the radiation-curable resin layer obtained by, for example, the above-mentioned radiation irradiation step is cured. When the cutting is performed in a state where the radiation-curable resin layer is not cured, when the side end of the optical semiconductor element sealing sheet is to be separated and removed after cutting, the adhesion between the removed side end and the radiation-curable resin layer in the remaining optical semiconductor device is high, and the following undesirable conditions may occur: the radiation-curable resin layer in the remaining optical semiconductor device is damaged due to the close contact and mutual pulling, and a part of the radiation-curable resin layer in the side end to be removed is transferred and attached to the remaining optical semiconductor device. In contrast, by providing the above-mentioned cutting step in which the cutting is performed in a state where the radiation-curable resin layer is cured, the radiation-curable resin layer is cured to form a cured sealing layer, and therefore, the adhesion of the side of the cut portion is low, and the occurrence of the above-mentioned undesirable conditions can be suppressed.

[0209] In addition, when the radiation-curable resin layer is cured by irradiating it with radiation, curing is hindered on the side where oxygen is present, and the curing is likely to be insufficient. In contrast, according to the above manufacturing method including the above cutting process, by cutting off and removing the insufficiently cured end portion in the above cutting process in a state where the radiation-curable resin layer is cured, it is possible to obtain an optical semiconductor device in which the side surface is sufficiently cured and the adhesion is reduced. In the optical semiconductor device manufactured in this way, after the curing of the radiation-curable resin layer, the adhesion of the side surface is sufficiently reduced. Therefore, when separating adjacent optical semiconductor devices in a tiled state, it is not easy to cause chip defects or adhesion of the chips of adjacent optical semiconductor devices. On the other hand, in the case where the above cutting process is not provided, the insufficiently cured side surface during tiling will contact adjacent optical semiconductor devices. Therefore, when attempting to separate adjacent optical semiconductor devices from each other, the following adverse conditions are likely to occur: the side surfaces are adhered to each other and pulled, a defect occurs in the radiation-curable resin layer of one optical semiconductor device, or a part of the radiation-curable resin layer of one optical semiconductor device is transferred and adhered to another optical semiconductor device.

[0210] (Tiling process)

[0211] In the above tiling process, a plurality of optical semiconductor devices obtained by the above cutting process are arranged and tiled in contact with each other along the planar direction. By operating in this way, it is possible to manufacture, for example Figure 3 the optical semiconductor device 20 shown. The sealing performance of the optical semiconductor element of the tiled optical semiconductor device is excellent, and when separating adjacent optical semiconductor devices from each other, it is not easy to cause chip defects or adhesion of the chips of adjacent optical semiconductor devices.

[0212] Examples

[0213] Hereinafter, the present invention will be described in more detail by listing examples, but the present invention is not limited to these examples at all.

[0214] Example 1

[0215] <TAC film / adhesive binder layer>

[0216] 69.7 parts by mass of 2-ethylhexyl acrylate (2EHA) as a monomer component, 10 parts by mass of 2-methoxyethyl acrylate (MEA), 13 parts by mass of 2-hydroxyethyl acrylate (HEA), 6 parts by mass of N-vinyl-2-pyrrolidone (NVP), 1.3 parts by mass of N-hydroxyethylacrylamide (HEAA), 0.1 part by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 200 parts by mass of ethyl acetate as a polymerization solvent were put into a separable flask, and stirred for 1 hour while introducing nitrogen. By performing such an operation, after removing oxygen in the polymerization system, the temperature was raised to 63°C, and the reaction was carried out for 10 hours, and ethyl acetate was added to obtain an acrylic polymer solution having a solid content concentration of 30% by mass. With respect to 100 parts by mass of the above acrylic polymer, 0.2 part by mass of an isocyanate-based crosslinking agent (trade name "TAKENATE D110N", manufactured by Mitsui Chemicals, Inc.) as a crosslinking agent, 0.15 part by mass of γ-glycidoxypropyltrimethoxysilane (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, and 0.2 part by mass of a polyol (trade name "EDP-300", manufactured by ADEKA Corporation) obtained by adding ethylenediamine to propylene oxide as a crosslinking accelerator were added to prepare an adhesive composition (solution). Next, the above adhesive composition (solution) was applied to the release-treated surface of a release liner (separator) (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying reached 25 μm, and heated and dried at 60°C for 1 minute and at 155°C for 1 minute under normal pressure to obtain a double-sided adhesive sheet as an adhesive layer. Then, for the non-treated surface of a triacetyl cellulose (TAC) film (trade name "DSR3-LR", manufactured by Dainippon Printing Co., Ltd., total thickness of 45 μm, anti-glare / anti-reflection treatment), a manual roller was used to bond the adhesive surface of the adhesive layer without mixing air bubbles. By performing such an operation, a laminate having a structure of [TAC film / adhesive layer / release liner] was produced.

[0217] <PET film / ultraviolet curable adhesive layer / radiation non-curable adhesive layer>

[0218] (ultraviolet curable adhesive layer)

[0219] 189.77 parts by mass of butyl acrylate (BA), 38.04 parts by mass of cyclohexyl acrylate (CHA), 85.93 parts by mass of 2-hydroxyethyl acrylate (HEA), 0.94 parts by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 379.31 parts by mass of methyl ethyl ketone as a polymerization solvent were placed in a 1L round-bottom separable flask equipped with a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade for polymerization experimental equipment, and nitrogen replacement was performed at room temperature for 6 hours while stirring. Thereafter, polymerization was performed while maintaining at 65°C for 4 hours and maintaining at 75°C for 2 hours while stirring under nitrogen inflow to obtain a resin solution.

[0220] Next, the obtained resin solution was cooled to room temperature. Thereafter, 5.74 parts by mass of 2-isocyanatoethyl methacrylate (MOI) (trade name "Karenz MOI", manufactured by Showa Denko) as a compound having a polymerizable carbon-carbon double bond was added to the above resin solution. Furthermore, 0.03 parts by mass of dibutyltin (IV) dilaurate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 50° C. for 24 hours in an air atmosphere to obtain a base polymer.

[0221] With respect to 100 parts by mass of the solid content of the obtained base polymer, 1.5 parts by mass of an isocyanate compound (trade name "CORONATE L", manufactured by Tosoh Corporation, solid content 75% by mass) and 1 part by mass of 2,2-dimethoxy-1,2-diphenyl-1-one (trade name "omnirad 651", manufactured by IGM Resins Italia Srl) were mixed. Toluene was used as a diluent and the solid content was adjusted to 20 to 40% by mass to obtain an adhesive solution (1).

[0222] The adhesive solution (1) was applied to a treated surface of a PET film (trade name "T912E75 (UE80-)", manufactured by Mitsubishi Chemical Corporation, thickness 75 μm) in such a manner that the thickness after drying was 112.5 μm, and then dried by heating at 50° C. for 1 minute and at 125° C. for 5 minutes at normal pressure to form an ultraviolet curable adhesive layer (1). On the other hand, the adhesive solution (1) obtained above was applied to a release treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) in such a manner that the thickness after drying was 112.5 μm, and then dried by heating at 50° C. for 1 minute and at 125° C. for 5 minutes at normal pressure to form an ultraviolet curable adhesive layer (2).

[0223] Then, using a hand roller, the adhesive surfaces of the UV-curable adhesive layer (1) formed on the PET film and the UV-curable adhesive layer (2) formed on the release liner were bonded to each other in a manner that did not include air bubbles, thereby forming one UV-curable adhesive layer. Thereafter, the release liner was peeled off. In this manner, a laminate having the structure of [PET film / UV-curable adhesive layer] was produced.

[0224] (Radiation non-curing adhesive layer)

[0225] 189.77 parts by mass of butyl acrylate (BA), 38.04 parts by mass of cyclohexyl acrylate (CHA), 85.93 parts by mass of 2-hydroxyethyl acrylate (HEA), 0.94 parts by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 379.31 parts by mass of methyl ethyl ketone as a polymerization solvent were placed in a polymerization experimental apparatus equipped with a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade on a 1L round-bottom separable flask, and nitrogen substitution was performed at room temperature for 6 hours while stirring. Thereafter, polymerization was performed while maintaining at 65°C for 4 hours and maintaining at 75°C for 2 hours while stirring under nitrogen inflow to obtain a resin solution.

[0226] The obtained resin solution was mixed with 1.5 parts by mass of an isocyanate compound (trade name "CORONATE L", manufactured by Tosoh Corporation, solid content: 75% by mass) based on 100 parts by mass of the solid content of the base polymer. Toluene was used as a diluent to adjust the solid content to 20 to 40% by mass, thereby obtaining an adhesive solution (2).

[0227] The adhesive solution (2) was applied onto the release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) to a thickness of 25 μm after drying, and dried by heating at 125° C. for 2 minutes under normal pressure to form a radiation non-curing adhesive layer.

[0228] (PET film / ultraviolet curable adhesive layer / radiation non-curable adhesive layer)

[0229] The radiation non-curing adhesive layer was applied to the ultraviolet curing adhesive layer of the laminate having the structure of [PET film / ultraviolet curing adhesive layer] using a hand roller so as not to mix in bubbles. In this way, a laminate having the structure of [PET film / ultraviolet curing adhesive layer / radiation non-curing adhesive layer / release liner] was prepared.

[0230] <Sheet for sealing optical semiconductor elements>

[0231] The release liner was peeled off from the laminate having the structure of [TAC film / adhesive adhesive layer / release liner], and the exposed adhesive layer was attached to the PET film surface of the laminate having the structure of [PET film / ultraviolet curable adhesive layer / radiation non-curable adhesive layer / release liner] using a manual roller in a manner that does not mix bubbles. Thereafter, the laminate was aged at 50° C. for 48 hours to produce a sheet for encapsulating optical semiconductor elements of Example 1 having the layer structure of [TAC film / adhesive adhesive layer / PET film / ultraviolet curable adhesive layer / radiation non-curable adhesive layer / release liner].

[0232] Embodiments 2 to 5

[0233] Optical semiconductor element sealing sheets of Examples 2 to 5 were prepared in the same manner as in Example 1 except that the amounts of 2-isocyanatoethyl methacrylate (MOI) and dibutyltin (IV) dilaurate were changed as shown in the table in the preparation of the ultraviolet curable adhesive layer.

[0234] Comparative Example 1

[0235] The adhesive solution (2) prepared in Example 1 was applied to a treated surface of a PET film (trade name "T912E75 (UE80-)", manufactured by Mitsubishi Chemical Corporation, thickness 75 μm) in such a manner that the thickness after drying was 125 μm, and then dried at 50°C for 1 minute and at 125°C for 5 minutes under normal pressure to form a radiation non-curing adhesive layer (1). On the other hand, the adhesive solution (2) prepared in Example 1 was applied to a release treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) in such a manner that the thickness after drying was 125 μm, and then dried at 50°C for 1 minute and at 125°C for 5 minutes under normal pressure to form a radiation non-curing adhesive layer (2).

[0236] Then, using a hand roller, the adhesive layers of the radiation non-curing adhesive layer (1) formed on the PET film and the radiation non-curing adhesive layer (2) formed on the release liner were bonded to each other in a manner that did not include air bubbles, thereby forming one radiation non-curing adhesive layer. In this way, a laminate having a structure of [PET film / radiation non-curing adhesive layer / release liner] was produced.

[0237] The release liner was peeled off from the laminate having the structure of [TAC film / adhesive adhesive layer / release liner] prepared in Example 1, and the exposed adhesive adhesive layer was attached to the PET film surface of the laminate having the structure of [PET film / radiant non-curing adhesive layer / release liner] using a hand roller in a manner that does not mix bubbles. Thereafter, aging was performed at 50° C. for 48 hours to prepare a sheet for encapsulating optical semiconductor elements of Comparative Example 1 having the layer structure of [TAC film / adhesive adhesive layer / PET film / radiant non-curing adhesive layer / release liner].

[0238] Comparative Example 2

[0239] In the preparation of the ultraviolet curable adhesive layer, an adhesive solution (3) was obtained in the same manner as in the adhesive solution (1) of Example 1 except that the blending amounts of 2-isocyanatoethyl methacrylate (MOI) and dibutyltin (IV) dilaurate were changed as shown in the table.

[0240] Then, the prepared adhesive solution (3) was applied to a treated surface of a PET film (trade name "T912E75 (UE80-)", manufactured by Mitsubishi Chemical Corporation, thickness 75 μm) in such a manner that the thickness after drying was 125 μm, and then dried at 50° C. for 1 minute and at 125° C. for 5 minutes under normal pressure to form an ultraviolet curable adhesive layer (3). On the other hand, the prepared adhesive solution (3) was applied to a release treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) in such a manner that the thickness after drying was 125 μm, and then dried at 50° C. for 1 minute and at 125° C. for 5 minutes under normal pressure to form an ultraviolet curable adhesive layer (4).

[0241] Then, using a hand roller, the adhesive layers of the ultraviolet curable adhesive layer (3) formed on the PET film and the ultraviolet curable adhesive layer (4) formed on the release liner were bonded to each other in a manner that did not mix with air bubbles, thereby forming one ultraviolet curable adhesive layer. In this way, a laminate having a structure of [PET film / ultraviolet curable adhesive layer / release liner] was produced.

[0242] The release liner was peeled off from the laminate having the structure of [TAC film / adhesive adhesive layer / release liner] prepared in Example 1, and the exposed adhesive adhesive layer was attached to the PET film surface of the laminate having the structure of [PET film / ultraviolet curable adhesive layer / release liner] using a hand roller in a manner that does not mix bubbles. Thereafter, aging was performed at 50° C. for 48 hours to prepare a sheet for optical semiconductor element sealing of Comparative Example 2 having the layer structure of [TAC film / adhesive adhesive layer / PET film / ultraviolet curable adhesive layer / release liner].

[0243] <Evaluation>

[0244] The ultraviolet curable pressure-sensitive adhesive layers and optical semiconductor element sealing sheets obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in the table.

[0245] (1) Hardness based on nanoindentation method

[0246] For the optical semiconductor element sealing sheets obtained in the examples and comparative examples, the hardness of the surface of the ultraviolet curable adhesive layer before and after curing was measured by the nanoindentation method. The curing of the ultraviolet curable adhesive layer was implemented by ultraviolet irradiation from the TAC film side according to the following ultraviolet irradiation conditions. Then, the optical semiconductor element sealing sheet of the ultraviolet curable adhesive layer before and after curing was frozen at -40°C to -30°C for 10 to 15 minutes, and then cut along the thickness direction using a microtome under the freezing conditions to expose the cross section of the ultraviolet curable adhesive layer. Then, the optical semiconductor element sealing sheet with the exposed cross section was fixed to the metal table attached to the device by solidifying the Pentel correction fluid (product number "XEZL1-W"), and then the polyimide film was pasted on the window of the device to shield the light, and then the evaluation was performed. Using a nanoindenter (trade name "TriboIndenter", HYSITRON Inc.), the nanoindentation measurement of the surface of the ultraviolet curable adhesive layer before and after curing was performed using the following nanoindentation measurement conditions. And, the obtained hardness is shown in Table 1.

[0247] <Ultraviolet irradiation conditions>

[0248] Ultraviolet irradiation device: Trade name "UM810", manufactured by Nitto Seiki Co., Ltd.

[0249] Light source: high pressure mercury lamp

[0250] Irradiation intensity: 50mW / cm 2 (Measurement equipment: trade name "Ultraviolet illuminometer UT-101", manufactured by USIO Electric Co., Ltd.)

[0251] Irradiation time: 100 seconds

[0252] Accumulated light intensity: 5000mJ / cm 2

[0253] <Nanoindentation Measurement Conditions>

[0254] Use indenter: Berkovich (triangular pyramid type)

[0255] Measurement method: Single indentation measurement

[0256] Measurement temperature: 23°C

[0257] Indentation depth setting: 3.0μm

[0258] Load speed: 500nm / s

[0259] Unloading speed: 500nm / s

[0260] (2) Cutting evaluation

[0261] For the optical semiconductor element sealing sheet obtained in the examples and comparative examples, a manual roller was used to bond the entire surface of the adhesive layer exposed by peeling off the release liner to the pattern surface of the substrate (trade name "lead-free general substrate ICB93SGPBF", manufactured by SUNHAYATO Corporation) to produce a test sample. It should be noted that the adhesive layer area of ​​the optical semiconductor element sealing sheet is larger than the area of ​​the substrate to be bonded. The bonding was performed in an environment of a temperature of 22°C and a humidity of 50% in a manner that does not mix in bubbles. Thereafter, for the above-mentioned test sample, ultraviolet irradiation was performed from the TAC film side according to the following ultraviolet irradiation conditions (1) to cure the ultraviolet curable adhesive layer. It should be noted that for the test sample obtained using the optical semiconductor element sealing sheet of Comparative Example 1 which does not have a ultraviolet curable adhesive layer, no ultraviolet irradiation was performed.

[0262] <Ultraviolet irradiation conditions (1)>

[0263] Ultraviolet irradiation device: Trade name "UM810", manufactured by Nitto Seiki Co., Ltd.

[0264] Light source: high pressure mercury lamp

[0265] Irradiation intensity: 50mW / cm 2 (Measurement device: trade name "Ultraviolet Illuminance Meter UT-101", manufactured by USIO Electric Co., Ltd.)

[0266] Irradiation time: 100 seconds

[0267] Accumulated light intensity: 5000mJ / cm 2

[0268] After ultraviolet irradiation, a dicing tape (trade name "NBD-5172K", manufactured by Nitto Denko Corporation) is attached to the side of the test sample where the optical semiconductor element sealing sheet is not attached, i.e., the substrate surface. A dicing ring for cutting is attached to the adhesive surface of the dicing tape. After attachment, it is placed in a light-shielded environment at a temperature of 22°C for 30 minutes. Thereafter, a blade cut is performed at a position 5 mm inward from the substrate side end using the following cutting conditions for the laminate of the test sample and the dicing tape.

[0269] <Cutting conditions>

[0270] Cutting device: Trade name "DFD-6450", manufactured by DISCO

[0271] Cutting method: single cutting

[0272] Cutting speed: 30mm / sec

[0273] Cutting blade: Trade name "P1A861 SDC400N75BR597", manufactured by DISCO

[0274] Cutting blade speed: 30,000rpm

[0275] Blade height: 85μm

[0276] Water volume: 1.5L / min

[0277] Cutting interval: 10mm

[0278] Distance of one cut: Total length of the test sample

[0279] It should be noted that the blade used for cutting is a blade for cutting clothing by the following method.

[0280] A cutting ring and a board (trade name "DRESSER BOARD BGCA0172", manufactured by DISCO) were attached to the adhesive layer of a cutting tape (trade name "NBD-7163K", manufactured by Nitto Denko Corporation) to prepare a workpiece for processing. Next, the obtained workpiece was cut under the following clothing cutting conditions to obtain a blade for the above-mentioned blade cutting.

[0281] <Clothing cutting conditions>

[0282] Cutting device: Product name "DFD-6450", made by DISCO

[0283] Cutting method: single cutting

[0284] Cutting speed: 55mm / sec

[0285] Cutting blade: Trade name "P1A861 SDC400N75BR597" (new), made by DISCO

[0286] Cutting blade speed: 35,000rpm

[0287] Blade height: 500μm

[0288] Water volume: 1.5L / min

[0289] 1 cutting distance: full length of the board

[0290] Cutting interval: 1mm scale

[0291] Cutting times: 100 times

[0292] After the dicing with the blade, ultraviolet rays were irradiated from the dicing tape substrate side under the following ultraviolet irradiation conditions (2) to reduce the peel strength of the dicing tape with respect to the substrate.

[0293] <Ultraviolet irradiation conditions (2)>

[0294] Ultraviolet irradiation device: Trade name "UM810", manufactured by Nitto Seiki Co., Ltd.

[0295] Light source: high pressure mercury lamp

[0296] Irradiation intensity: 50mW / cm 2 (Measurement device: trade name "Ultraviolet Illuminance Meter UT-101", manufactured by USIO Electric Co., Ltd.)

[0297] Irradiation time: 10 seconds

[0298] Accumulated light intensity: 500mJ / cm 2

[0299] Thereafter, the laminate of the test sample and the substrate cut into short strips by razor cutting was peeled from the dicing tape. The case where peeling of the test sample from the substrate was observed during cutting was evaluated as "B", and the case where no peeling was observed was evaluated as "A".

[0300] (3) Arithmetic mean height Sa of the cross section

[0301] The stack of the test sample and substrate cut into short strips in the above-mentioned cutting evaluation is peeled off from the cutting tape. Then, the cross section of the cured product of the exposed ultraviolet curable resin layer is measured by the arithmetic mean height Sa. It should be noted that, for Comparative Example 1 without an ultraviolet curable resin layer, the cross section of the radiation non-curing adhesive layer is measured by the arithmetic mean height Sa. Specifically, a double-sided adhesive tape (trade name "No.5000NS", Nitto Denko Corporation) is attached to the surface of an unground Si mirror wafer. Then, on the exposed surface (the surface not in contact with the Si mirror wafer) of the double-sided adhesive tape, the above-mentioned short strip-shaped stack is attached with tweezers. It should be noted that the cutting section is attached in a manner that the cutting section is bonded to the double-sided adhesive tape, and the outermost surface (the surface farthest from the double-sided adhesive tape) becomes the cutting section that is cut last. The final cut surface was observed and measured using a laser microscope (product name "VK-X150", manufactured by Keyence Corporation). The PC software used was "Observation Application VK-H1XV2 Version: 2.5.0.0" (manufactured by Keyence Corporation). The objective lens used was "20X / 0.46OFN25 WD 3.1" (manufactured by Nikon Corporation). The roughness of the cut surface was measured using the "Shape Measurement" of the PC software according to the following measurement settings.

[0302] <Measurement Settings>

[0303] Measurement mode: Transparent body (outermost surface)

[0304] Measurement size: Standard (1024×768)

[0305] Measurement quality: high precision

[0306] Pitch: 0.75μm

[0307] Next, save the three-dimensional data obtained by the measurement. It should be noted that the state is made so that the cross section of the layer to be measured is fully projected from the left end to the right end of the screen (the cross section of the layer with a thickness of less than 250μm falls into the screen). Thereafter, the "slope correction" in the "image processing" of the PC software is performed. As a correction method, the surface slope correction (curve) is selected, and the slope correction is performed in a manner such that the cut surface becomes horizontal when the centers of the two lines converge at the center of the layer of the obtained observation image. After the slope correction, save the corrected three-dimensional data. Next, use the PC software for analysis "Multi-file Analysis Application VK-H1XM Version: 1.1.22.87" (manufactured by Keyence Corporation) to analyze the three-dimensional data. Select "Surface Roughness" of the PC software for analysis, select the entire layer cross section projected in the form of an image, and measure the arithmetic mean height Sa (μm).

[0308] (4) Wire drawing evaluation

[0309] The laminate of the two test samples cut into short strips in the above-mentioned cutting evaluation and the substrate is peeled off from the cutting tape. Next, the cut surfaces of the above-mentioned two laminates exposed by cutting are bonded to each other, and placed in an environment with a temperature of 50°C for 24 hours in this state. Thereafter, the two bonded short strips are taken out and placed in an environment with a temperature of 22°C and a humidity of 50% for 3 hours. Thereafter, an attempt is made to peel the bonded cut surfaces from each other by hand, and the case where it is impossible to peel or it is possible to peel but the stringing of the adhesive layer can be significantly confirmed is evaluated as "D", the case where it is possible to peel but the stringing of the adhesive layer can be slightly confirmed is evaluated as "C", the case where the peeling requires force but there is no stringing of the adhesive layer is evaluated as "B", and the case where the peeling does not require special force and there is no stringing of the adhesive layer is evaluated as "A".

[0310] [Table 1]

[0311] (Table 1)

[0312]

[0313] As shown in Table 1, the optical semiconductor element sealing sheet (Example) of the present invention can be evaluated as having good results in the cutting evaluation, excellent adhesion of the sheet to the optical semiconductor element and the substrate, and excellent sealing of the optical semiconductor element. In addition, it can be evaluated as having good results in the wire drawing evaluation, low adhesion on the side of the sealing portion, and when the adjacent optical semiconductor devices are separated from each other, it is not easy to cause the sheet to be damaged or the sheet to adhere to the adjacent optical semiconductor device.

[0314] On the other hand, in the case of not having an ultraviolet curable adhesive layer (Comparative Example 1), the result of the stringing evaluation was poor. In addition, in the case of not having an irradiation non-curable adhesive layer (Comparative Example 2), it can be evaluated that the result of the cutting evaluation was poor, and the sealing property of the optical semiconductor element was poor.

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, The optical semiconductor device comprises a base material portion and a sealing portion for sealing the optical semiconductor element provided on one surface of the base material portion. The semiconductor element sealing sheet may include a surface protection film on the surface of the substrate portion opposite to the sealing portion. When the semiconductor element sealing sheet does not include the surface protection film, the sheet includes the base material on one surface. When the semiconductor element sealing sheet includes the surface protection film, the surface protection film is provided on one surface. The sealing portion includes a radiation non-curing adhesive layer and a radiation curing resin layer. The sealing portion has the radiation non-curing adhesive layer on the surface of the sealing portion, and the radiation non-curing adhesive layer is on the optical semiconductor element side when the optical semiconductor element is sealed. The radiation-curable resin layer includes a polymer having a radiation-polymerizable functional group.

2. The optical semiconductor element sealing sheet according to claim 1, wherein The radiation curable resin layer is thicker than the radiation non-curable adhesive layer.

3. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The sealing portion includes a layer containing a colorant. The optical semiconductor element sealing sheet according to claim 1 or 2, comprising a layer having antiglare property and / or antireflection property. 5 . The optical semiconductor element sealing sheet according to claim 1 , comprising a layer containing a polyester-based resin and / or a polyimide-based resin as a main component.

6. The optical semiconductor element sealing sheet according to claim 1 or 2, wherein The hardness of the cross section of the radiation-curable resin layer after curing at a temperature of 23° C. measured by a nanoindentation method is 1.4 MPa or more.

7. An optical semiconductor device comprising: substrate; an optical semiconductor element disposed on the substrate; and A cured product obtained by curing the radiation-curable resin layer of the optical semiconductor element sealing sheet according to any one of claims 1 to 6, which seals the optical semiconductor element. The optical semiconductor device according to claim 7 , which is a backlight of a liquid crystal screen. 9 . An image display device comprising the backlight according to claim 8 and a display panel. 10 . The optical semiconductor device according to claim 7 , which is a self-luminous display device. 11 . An image display device comprising the self-luminous display device according to claim 10 .

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