JP2022129764A - Optical semiconductor element encapsulation sheet - Google Patents

Abstract

To provide an optical semiconductor element encapsulation sheet with excellent encapsulation properties of an optical semiconductor element, being less likely to occur a loss of a sheet and adhesion of sheets of adjacent optical semiconductor devices when the adjacent optical semiconductor devices are separated from each other.SOLUTION: An optical semiconductor element encapsulation sheet 1 is a sheet for encapsulating one or more optical semiconductor elements 6 arranged on a substrate 5. The optical semiconductor element encapsulation sheet 1 comprises a base material part 2, and an encapsulation part 3 provided on one surface of the base material part 2. The encapsulation part 3 encapsulates the optical semiconductor elements 6, having a radiation non-curable adhesive layer 32 and a radiation curable resin layer 31. The radiation curable resin layer 31 contains a polymer having a radiation polymerizable functional group.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a sheet for optical semiconductor element encapsulation. More specifically, it relates to a sheet for sealing one or more optical semiconductor elements arranged on a substrate.

For example, backlights used in liquid crystal display devices are known to have a structure in which a plurality of LEDs are arranged on a substrate and the plurality of LEDs are sealed with a sealing resin. As a method for collectively sealing the plurality of LEDs using the sealing resin, a liquid resin is poured into the region where the plurality of LEDs are arranged, and the plurality of LEDs are buried, and then heat or ultraviolet irradiation is performed. A method of curing a liquid resin is known (see, for example, Patent Document 1).

JP 2017-66390 A

However, in the method of encapsulating an optical semiconductor element such as an LED using a liquid resin, there are problems such as dripping when the liquid resin is applied and the liquid resin adhering to unintended areas, resulting in poor handling. there were.

On the other hand, instead of using a liquid resin, by adopting the form of a sealing sheet provided with a sealing layer for sealing the optical semiconductor element, it is easy and simple to manufacture the optical semiconductor in a short time. It is conceivable to seal the device. Here, it is important that the sheet for encapsulation has excellent sealing properties of the optical semiconductor element and excellent adhesion to the optical semiconductor element or the substrate provided with the optical semiconductor element in order to sufficiently seal the optical semiconductor element. is.

By the way, with the improvement of 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 for signage such as advertisement displays and bulletin boards in outdoors and public facilities is also progressing. However, when a large-screen image display device is manufactured, there arises a problem that the yield is lowered and the manufacturing cost is increased. BACKGROUND ART In order to manufacture a large-screen image display device at a lower cost, a tiling display, in which a plurality of optical semiconductor devices such as an image display device are arranged in tiles, has been studied. When a plurality of optical semiconductor devices are arranged in a tiled manner, that is, when tiling, positional correction is performed when the adjacent optical semiconductor devices are misaligned or need to be rearranged. .

Here, when tiling the optical semiconductor devices in which the optical semiconductor element is sealed with the sealing sheet, it is necessary to temporarily separate the adjacent optical semiconductor devices in order to correct the position during tiling. However, when separating, the encapsulating sheet in one optical semiconductor device and the encapsulating sheet in the other adjacent optical semiconductor device are in close contact with each other, causing damage to the encapsulating sheet in one optical semiconductor device. There may be a problem that a part of one encapsulating sheet is transferred and attached to the other optical semiconductor device. Such defects are particularly likely to occur in the encapsulating sheet, which has excellent adhesion to optical semiconductor elements and substrates.

The present invention has been devised under such circumstances, and an object of the present invention is to provide excellent encapsulation properties for optical semiconductor elements, and to prevent sheet damage and damage when separating adjacent optical semiconductor devices from each other. To provide a sheet for encapsulating an optical semiconductor element to which the sheet of an adjacent optical semiconductor device hardly adheres.

As a result of intensive studies to achieve the above object, the present inventors have found that a sealing portion having a non-radiation-curable pressure-sensitive adhesive layer and a radiation-curable resin layer is provided, and the radiation-curable resin layer comprises a radiation-polymerizable functional group. According to the optical semiconductor element encapsulating sheet containing a polymer having a superior sealing property of the optical semiconductor element, when separating the adjacent optical semiconductor devices, the sheet is damaged or the sheets of the adjacent optical semiconductor devices are separated. It was found that adhesion hardly occurs. The present invention has been completed based on these findings.

That is, the present invention provides a sheet for sealing one or more optical semiconductor elements arranged on a substrate,
A base member, and a sealing portion provided on one surface of the base member for encapsulating the optical semiconductor element,
The sealing portion has a radiation non-curable adhesive layer and a radiation curable resin layer,
The radiation-curable resin layer provides a sheet for optical semiconductor element encapsulation containing a polymer having a radiation-polymerizable functional group.

The sheet for encapsulating an optical semiconductor element includes, as described above, a sealing portion in which a non-radiation-curable pressure-sensitive adhesive layer and a radiation-curable resin layer are laminated. The said sealing part is an area|region which seals an optical-semiconductor element in the said sheet|seat for optical-semiconductor element sealing. The radiation-curable resin layer contains a polymer having a radiation-polymerizable functional group. The polymer having the radiation-polymerizable functional group present in the radiation-curable resin layer hardly migrates from the radiation-curable resin layer to the non-radiation-curable pressure-sensitive adhesive layer laminated thereon. Therefore, when the radiation is irradiated after sealing the optical semiconductor element, the radiation curable resin layer is sufficiently cured, the adhesion of the side surface of the sealing sheet is reduced, and the radiation non-curable adhesive layer is By suppressing unintended curing, the adhesive strength is less likely to decrease, the original adhesiveness can be exhibited, and the encapsulation of the optical semiconductor element is excellent. As a result, the sealing property of the optical semiconductor element is excellent, and at the same time, the adhesion between the side surfaces of the sealing portions of the adjacent optical semiconductor devices in the tiling state is low, and when the adjacent optical semiconductor devices are separated from each other, the optical semiconductor device Damage to the sheet on the side surface and adhesion of the sheet of the adjacent optical semiconductor device are less likely to occur. Moreover, the said base material part becomes a support body of the said sealing part, and by providing the said base material part, the said sheet|seat for optical-semiconductor element sealing is excellent in handleability. In addition, when dicing the optical semiconductor device after sealing the optical semiconductor element with the sheet for optical semiconductor element encapsulation to produce an optical semiconductor device, stickiness of the diced portion can be suppressed, and an optical semiconductor device having a good appearance can be produced. .

The radiation curable resin layer is preferably thicker than the radiation non-curable adhesive layer. By having such a configuration, the adhesion after curing of the radiation curable resin layers in the adjacent optical semiconductor devices is lower than the high adhesion between the radiation non-curable adhesive layers in the adjacent optical semiconductor devices in the tiling state. Since the adhesiveness is dominant, the adhesiveness between the sealing portions is even lower, and when the adjacent optical semiconductor devices are separated from each other, the damage of the sheet and adhesion of the sheets of the adjacent optical semiconductor devices are much less likely to occur. Further, when dicing the optical semiconductor device after sealing the optical semiconductor element with the optical semiconductor element encapsulating sheet, stickiness of the diced portion can be further suppressed, and an optical semiconductor device having a good appearance can be produced. can be done.

The sealing portion may include a layer containing a coloring agent. By having such a configuration, when the optical semiconductor device is applied to a display by tiling, color mixing of light emitted from each optical semiconductor element is suppressed when the optical semiconductor device is used, and the optical semiconductor device is improved. The appearance of the display can be adjusted when not in use.

The sheet for encapsulating optical semiconductor elements preferably comprises a layer having antiglare properties and/or antireflection properties. By having such a configuration, when the optical semiconductor device is applied to a display by tiling, glossiness and light reflection of the display can be suppressed, and the appearance of the display can be improved.

The optical semiconductor element encapsulating sheet preferably has a layer containing a polyester-based resin and/or a polyimide-based resin as a main component. By having such a structure, the sheet for optical semiconductor element encapsulation has excellent heat resistance, the thermal expansion of the sheet for optical semiconductor element encapsulation can be suppressed in a high temperature environment, and the dimensional stability is improved. In addition, since rigidity as a sheet can be imparted, handleability and holdability are improved.

It is preferable that the cross section of the radiation-curable resin layer after curing has a hardness of 1.4 MPa or more by a nanoindentation method at a temperature of 23°C. With such a configuration, the radiation-curable resin layer has an appropriate hardness after curing, and when the adjacent optical semiconductor devices are separated in a tiling state, damage to the sheet or damage to the adjacent optical semiconductor devices may occur. Sticking of the sheets of the device is much less likely.

Further, the present invention provides a substrate, an optical semiconductor element arranged on the substrate, and a cured product obtained by curing the radiation-curable resin layer of the optical semiconductor element encapsulating sheet for encapsulating the optical semiconductor element. to provide an optical semiconductor device comprising: In such an optical semiconductor device, when the adjacent optical semiconductor devices are separated from each other after the radiation-curable resin is cured, the sheets are less likely to be damaged or the sheets of the adjacent optical semiconductor devices to adhere to each other. Moreover, when dicing, stickiness of the diced portion can be suppressed, and an optical semiconductor device with a good appearance can be manufactured.

The optical semiconductor device may be a backlight for a liquid crystal screen. Further, the optical semiconductor device may be a self-luminous display device. Since the optical semiconductor device has a good appearance when applied to an optical semiconductor device having a display, it is preferably applied as a backlight for a liquid crystal screen or a self-luminous display device.

The present invention also provides an image display device comprising the above backlight and a display panel.

Further, the present invention provides an image display device including the self-luminous display device.

According to the sheet for encapsulating an optical semiconductor element of the present invention, although the sealing property of the optical semiconductor element is excellent, when the adjacent optical semiconductor devices are separated from each other, damage of the sheet and adhesion of the sheet of the adjacent optical semiconductor device occur. Hateful. Therefore, after the tiling of the optical semiconductor devices, if the positions of the adjacent optical semiconductor devices are misaligned or if rearrangement is necessary, the positions can be easily corrected without problems. Device loss can be reduced, and a good-looking display can be manufactured economically.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the sheet|seat for optical-semiconductor element sealing which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the optical semiconductor device using the sheet|seat for optical-semiconductor element sealing which concerns on one Embodiment of this invention. FIG. 3 is an external view showing an embodiment of an optical semiconductor device produced by tiling the optical semiconductor devices shown in FIG. 2 ; FIG. 4 is a cross-sectional view showing a state of a sealing step in one embodiment of a method for manufacturing an optical semiconductor device; FIG. 5 represents a cross-sectional view showing the laminate obtained after the sealing step shown in FIG. 4 ; FIG. 6 is a cross-sectional view showing a laminate obtained by subjecting the laminate shown in FIG. 5 to a radiation irradiation step; FIG. 7 is a cross-sectional view showing a dicing position in a dicing step of the laminate shown in FIG. 6;

[Sheet for optical semiconductor element encapsulation]
The sheet for encapsulating an optical semiconductor element of the present invention includes at least a substrate portion and a sealing portion provided on one surface of the substrate portion for sealing the optical semiconductor element. In this specification, the sheet for encapsulating optical semiconductor elements refers to a sheet for encapsulating one or more optical semiconductor elements arranged on a substrate. Moreover, in this specification, "encapsulating the optical semiconductor element" means embedding at least part of the optical semiconductor element in the sealing portion.

The sheet for optical semiconductor element encapsulation of the present invention may include a release liner in addition to the base member and the encapsulation portion. In this case, the release liner is attached to the surface of the sealing portion opposite to the base portion. The release liner is used as a protective material for the sealing portion, and is peeled off when sealing the optical semiconductor element. Note that the release liner does not necessarily have to be provided.

In addition, the sheet for optical semiconductor element encapsulation of the present invention may have a surface protective film on the surface of the substrate portion (the surface opposite to the sealing portion). For example, when an optical film described later is used as the base material, the optical film can be protected until use. Note that the surface protective film may not necessarily be provided.

An embodiment of the sheet for optical semiconductor element encapsulation of the present invention will be described below. FIG. 1 is a cross-sectional view showing one embodiment of the sheet for optical semiconductor element encapsulation of the present invention. As shown in FIG. 1, the optical semiconductor element encapsulating sheet 1 can be used for encapsulating one or more optical semiconductor elements arranged on a substrate. A sealing part 3 and a release liner 4 are provided. 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 opposite to the side having the base material portion 2). In other words, the sheet 1 for optical-semiconductor element encapsulation includes the substrate portion 2, the encapsulation portion 3, and the release liner 4 in this order. The base material part 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 with an adhesive layer 22 interposed therebetween. The sealing portion 3 is composed of a radiation curable resin layer 31 and a radiation non-curable adhesive layer 32 .

The sheet for encapsulating optical semiconductor elements preferably comprises a layer having antiglare properties and/or antireflection properties. By having such a configuration, when the optical semiconductor device is applied to a display by tiling, glossiness and light reflection of the display can be suppressed, and the appearance of the display can be improved. The layer having antiglare properties includes an antiglare treatment layer. Examples of the layer having antireflection properties include an antireflection treatment layer. Antiglare treatment and antireflection treatment can be carried out by known or common methods. The antiglare layer and the antireflection layer may be the same layer or different layers. The antiglare and/or antireflection layer may have only one layer, or may have two or more layers.

The antiglare and/or antireflection layer is a layer included in the substrate portion, a layer included in the sealing portion, or a layer not included in the substrate portion and the sealing portion. Although any layer may be used, it is preferably a layer contained in the base material part and/or the sealing part, and more preferably a layer contained in the base material part.

It is preferable that the sheet for optical semiconductor element encapsulation has a layer containing a polyester-based resin and/or a polyimide-based resin as a main component (a component having the highest mass ratio among constituent resins). By having such a structure, the sheet for optical semiconductor element encapsulation has excellent heat resistance, the thermal expansion of the sheet for optical semiconductor element encapsulation can be suppressed in a high temperature environment, and the dimensional stability is improved. In addition, since rigidity as a sheet can be imparted, handleability and holdability are improved. The layer containing the polyester-based resin and/or polyimide-based resin as a main component may have only one layer, or may have two or more layers.

The layer containing the polyester-based resin and/or the polyimide-based resin as a main component is not included in the layer included in the base material portion, the layer included in the sealing portion, or the base portion and the sealing portion. Although it may be any other layer, it is preferably a layer contained in the base material part and/or the sealing part, and more preferably a layer contained in the base material part.

<Sealing part>
The sealing portion has a resin layer (radiation-curable resin layer) that is cured by irradiation with radiation and an adhesive layer that is not cured by radiation (non-radiation-curable adhesive layer).

(Radiation curable resin layer)
The radiation-curable resin layer contains at least a polymer having a radiation-polymerizable functional group. The polymer having the radiation-polymerizable functional group present in the radiation-curable resin layer hardly migrates from the radiation-curable resin layer to the non-radiation-curable pressure-sensitive adhesive layer laminated thereon. Therefore, when the radiation is irradiated after sealing the optical semiconductor element, the radiation curable resin layer is sufficiently cured, the adhesion of the side surface of the sealing sheet is reduced, and the radiation non-curable adhesive layer is By suppressing unintended curing, the adhesive strength is less likely to decrease, the original adhesiveness can be exhibited, and the encapsulation of the optical semiconductor element is excellent. As a result, the sealing property of the optical semiconductor element is excellent, and at the same time, the adhesion between the side surfaces of the sealing portions of the adjacent optical semiconductor devices in the tiling state is low, and when the adjacent optical semiconductor devices are separated from each other, the optical semiconductor device Damage to the sheet on the side surface and adhesion of the sheet of the adjacent optical semiconductor device are less likely to occur.

On the other hand, when a conventional radiation-curable resin layer containing a non-radiation-polymerizable polymer as a base polymer and using a radiation-polymerizable monomer or oligomer as a curable component is used, the above radiation-polymerizable resin layer is used. Monomers and oligomers tend to migrate to the laminated non-radiation-curable pressure-sensitive adhesive layer. In this case, even if such a radiation-curable resin layer with a reduced amount of the curable component is cured, the curing is insufficient, and the adhesion of the side surface of the sealing sheet is unlikely to decrease, and the stickiness of the side surface is sufficiently reduced. I can't. In addition, the non-radiation-curing pressure-sensitive adhesive layer into which the curable component has penetrated undergoes unintended curing upon exposure to radiation, resulting in a decrease in adhesive force and failure to exhibit the original adhesion, resulting in the optical semiconductor device. result in poor sealing performance.

In addition, when dicing the optical semiconductor device after sealing the optical semiconductor element with the sheet for optical semiconductor element encapsulation to produce an optical semiconductor device, stickiness of the diced portion can be suppressed, and an optical semiconductor device having a good appearance can be produced. . Furthermore, when a conventional radiation-curable resin layer is used, the radiation-polymerizable monomers and oligomers have low compatibility in the radiation-curable resin layer, resulting in poor transparency after curing. On the other hand, the sheet for optical semiconductor element encapsulation of the present invention has the radiation-curable resin layer, and therefore has excellent transparency after curing.

The radiation-curable resin layer is preferably an adhesive resin layer, that is, a radiation-curable adhesive layer. By having such a configuration, when encapsulating the optical semiconductor element, the optical semiconductor element can be easily embedded, and the base portion, the radiation non-curable adhesive layer, and the optical semiconductor element can be easily embedded before the radiation curing. It has excellent adhesion to the element, and is superior in the encapsulation of the optical semiconductor element. Examples of the radiation include active energy rays such as electron beams, ultraviolet rays, α rays, β rays, γ rays, and X rays. Among them, ultraviolet rays are preferred.

The radiation-curable resin layer preferably contains the polymer having the radiation-polymerizable functional group as a base polymer (that is, the polymer having the highest content). The content of the polymer having a radiation-polymerizable functional group in the radiation-curable resin layer is 50% by mass or more (for example, 50 to 100% by mass) with respect to 100% by mass of the total amount of the radiation-curable resin layer. is preferred, more preferably 80% by mass or more (eg, 80 to 100% by mass), still more preferably 90% by mass or more (eg, 90 to 100% by mass). When the content is 50% by mass or more, the curability of the radiation-curable resin layer is excellent, and the adhesiveness of the side surface is further reduced by irradiation with radiation. In addition, the transparency of the optical semiconductor element encapsulating sheet is further improved.

Examples of the radiation-polymerizable functional group include radiation-radical-polymerizable groups such as groups containing carbon-carbon unsaturated bonds such as ethylenically unsaturated groups, and radiation-cationically-polymerizable groups. Examples of the group containing a carbon-carbon unsaturated bond include vinyl group, propenyl group, isopropenyl group, acryloyl group and methacryloyl group. Examples of the radiation cationic polymerizable group include an epoxy group, an oxetanyl group, and an oxolanyl group. Among them, a group containing a carbon-carbon unsaturated bond is preferable, and an acryloyl group and a methacryloyl group are more preferable. The radiation-polymerizable functional group may be of one kind, or may be of two or more kinds. The position of the radiation-polymerizable functional group may be any of the side chain of the polymer, the inside of the main chain of the polymer, and the end of the main chain of the polymer.

The polymer having a radiation-polymerizable functional group is, for example, a functional group capable of forming a bond by causing a reaction between a polymer having a reactive functional group (first functional group) and the first functional group. (Second functional group) and the compound having the radiation polymerizable functional group can be reacted and bonded while maintaining the radiation polymerizability of the radiation polymerizable functional group. Therefore, the polymer having a radiation-polymerizable functional group 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. and preferably include

Combinations of the first functional group and the second functional group include, for example, a carboxy group and an epoxy group, an epoxy group and a carboxy group, a carboxy group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, An isocyanate group, a hydroxy group, and the like are included. Among these, a combination of a hydroxy group and an isocyanate group, and a combination of an isocyanate group and a hydroxy group are preferred from the viewpoint of ease of reaction tracking. The combination may be of only one type, or two or more types.

Examples of the polymer having the radiation-polymerizable functional group, that is, the polymer having the first functional group include acrylic polymers, urethane acrylate resins, epoxy resins, epoxy acrylate resins, oxetane resins, and silicone resins. , silicone acrylic resins, polyester resins, and the like. Among them, acrylic polymers are preferred. Only one kind of the above polymer may be used, or two or more kinds thereof may be used.

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

The acrylic polymer is preferably a polymer containing the largest proportion of structural units derived from (meth)acrylic acid ester. In the present specification, "(meth)acrylic" means "acrylic" and/or "methacrylic" (one or both of "acrylic" and "methacrylic"), and the same applies to others. .

Examples of the (meth)acrylic acid esters include hydrocarbon group-containing (meth)acrylic acid esters that may have an alkoxy group. The hydrocarbon group-containing (meth) acrylic acid ester in the hydrocarbon group-containing (meth) acrylic acid ester which may have an alkoxy group has a linear or branched aliphatic hydrocarbon group ( (Meth)acrylic acid alkyl esters, (meth)acrylic acid esters having an alicyclic hydrocarbon group such as (meth)acrylic acid cycloalkyl esters, (meth)acrylic acid aryl esters having an aromatic hydrocarbon group such as (meth)acrylates ) acrylic acid esters and the like. The hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group may be used alone or in combination of two or more.

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

Among the (meth)acrylic acid alkyl esters, linear or branched fatty acids having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 2 to 10, still more preferably 2 to 8) A (meth)acrylic acid alkyl ester having a group hydrocarbon group is preferred. When the number of carbon atoms is within the above range, the glass transition temperature of the acrylic polymer can be easily adjusted, and the adhesiveness of the radiation-curable resin layer can be made more appropriate.

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

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

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

The hydrocarbon group-containing (meth)acrylic acid ester optionally having an alkoxy group includes, among others, a (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group. is preferred, and it is more preferred to contain a (meth)acrylic acid ester having an alicyclic hydrocarbon group. In this case, the adhesion of the radiation-curable resin layer is well-balanced, and the encapsulation of the optical semiconductor element is excellent.

In order to appropriately exhibit the basic properties such as adhesiveness and adhesion to optical semiconductor elements due to the hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group, the radiation-curable resin layer has the following steps: The ratio of the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group in all the monomer components constituting the acrylic polymer having the first functional group is the total amount of all the monomer components (100 mol %), preferably 40 mol % or more, more preferably 50 mol % or more. In addition, the above ratio is preferably 95 mol % or less, more preferably 80 mol % or less, from the viewpoint of allowing the other monomer component to be copolymerized and obtaining the effect of the other monomer component.

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

The ratio of the (meth)acrylic acid ester having an alicyclic hydrocarbon group in all monomer components constituting the acrylic polymer having the first functional group is based on the total amount (100 mol%) of all the monomer components. , is preferably 1 mol % or more, more preferably 5 mol % or more. Moreover, the above ratio is preferably 30 mol % or less, more preferably 20 mol % or less.

For the purpose of introducing the first functional group, and for the purpose of modifying the cohesive force, heat resistance, etc., the acrylic polymer is a hydrocarbon group-containing (meth)acrylic acid that may have the alkoxy group. It may contain structural units derived from other monomer components copolymerizable with the ester. Examples of other monomer components include polar groups such as carboxy group-containing monomers, acid anhydride monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and nitrogen atom-containing monomers. Containing monomer etc. are mentioned. Only one kind of each of the other monomer components may be used, or two or more kinds thereof may be used.

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

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate and the like.

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

Examples of the sulfonic acid group-containing monomer include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, (meth) ) acryloyloxynaphthalenesulfonic acid and the like.

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

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

It is preferable that a hydroxy group-containing monomer is included as the polar group-containing monomer constituting the acrylic polymer. Introduction of the first functional group is facilitated by using a hydroxyl group-containing monomer. In addition, the acrylic polymer and the radiation-curable resin layer have excellent water resistance, and the sheet for encapsulating optical semiconductor elements is resistant to fogging and has excellent whitening resistance even when used in a high-humidity environment.

As the hydroxy group-containing monomer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferable, and 2-hydroxyethyl (meth)acrylate is more preferable.

In order to appropriately exhibit the basic properties such as adhesiveness and adhesion to optical semiconductor elements due to the hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group, the radiation-curable resin layer has the following steps: The ratio of the polar group-containing monomer in the total monomer components (100 mol%) constituting the acrylic polymer having the first functional group is preferably 5 to 50 mol%, more preferably 10 to 40 mol%. be. In particular, the ratio of the hydroxy group-containing monomer is preferably within the above range from the viewpoint of improving the water resistance of the radiation-curable resin layer.

The acrylic polymer may contain a structural unit derived from a polyfunctional (meth)acrylate copolymerizable with the monomer component constituting the acrylic polymer in order to form a crosslinked structure in the polymer skeleton. Examples of the polyfunctional (meth)acrylate include hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, and neopentyl glycol di(meth)acrylate. , pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate and the like. Only one kind of the polyfunctional (meth)acrylate may be used, or two or more kinds thereof may be used.

In order to appropriately exhibit the basic properties such as adhesiveness and adhesion to optical semiconductor elements due to the hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group, the radiation-curable resin layer has the following steps: The ratio of the polyfunctional (meth)acrylate in the total monomer components (100 mol%) constituting the acrylic polymer having the first functional group is preferably 40 mol% or less, more preferably 30 mol% or less. .

As a combination of the first functional group and the second functional group, among others, it is technically difficult to produce a polymer having a highly reactive isocyanate group, and on the other hand, an acrylic polymer having a hydroxy group. From the viewpoint of ease of production and availability, a combination in which the first functional group is a hydroxy group and the second functional group is an isocyanate group is preferable.

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, and the like. be done. Only one kind of the above compounds may be used, or two or more kinds thereof may be used.

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 promotes curing of the radiation-curable resin layer. 0.5 mol or more, more preferably 1 mol or more, and still more preferably 3 mol with respect to 100 mol of the total amount of the structural portion derived from the acrylic polymer having the first functional group. 10 mol or more, more preferably 10 mol or more. The above content is, for example, 100 mol or less.

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

The acrylic polymer having a radiation-polymerizable functional group is prepared, for example, by 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 compound having the second functional group and the radiation-polymerizable functional group can be prepared by a method of condensation reaction or addition reaction with an acrylic polymer while maintaining the radiation-polymerizable property of the radiation-polymerizable functional group. .

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, but includes, for example, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a polymerization method by active energy ray irradiation (active energy ray polymerization method), and the like. Moreover, the acrylic polymer to be obtained may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

Various common solvents may be used in the polymerization of the monomer components. Examples of the solvent 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; cyclohexane, methylcyclohexane and the like. alicyclic hydrocarbons; and organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. Only one type of the solvent may be used, or two or more types may be used.

Polymerization initiators, chain transfer agents, emulsifiers and the like used for radical polymerization of the monomer components are not particularly limited and can be appropriately selected and used. The weight-average molecular weight of the acrylic polymer can be controlled by adjusting the amount of the polymerization initiator and the chain transfer agent used and the reaction conditions, and the amount used is appropriately adjusted according to these types.

As the polymerization initiator used for polymerization of the monomer component, a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), or the like can be used depending on the type of polymerization reaction. Only one kind of the polymerization initiator may be used, or two or more kinds thereof may be used.

Examples of the thermal polymerization initiator include, but are not limited to, azo polymerization initiators, peroxide polymerization initiators, redox polymerization initiators, and the like. The amount of the thermal polymerization initiator used is preferably 1 part by mass or less, more preferably 0 part by mass, with respect to 100 parts by mass of the total amount of all monomer components constituting the acrylic polymer having the first functional group. 0.005 to 1 part by mass, more preferably 0.02 to 0.5 part by mass.

Examples of the photopolymerization initiator include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, and photoactive oxime-based photopolymerization initiators. Initiators, benzoin photoinitiators, benzyl photoinitiators, benzophenone photoinitiators, ketal photoinitiators, thioxanthone photoinitiators, acylphosphine oxide photoinitiators, titanocene photoinitiators A photoinitiator etc. are mentioned. Among them, an acetophenone-based photopolymerization initiator is preferable.

Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone, 4-(t-butyl ) Dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propane-1 -one, methoxyacetophenone, and the like.

The amount of the photopolymerization initiator used is preferably 0.005 to 1 part by mass with respect to 100 parts by mass of the total amount of all monomer components constituting the acrylic polymer having the first functional group, and more It is preferably 0.01 to 0.7 parts by mass, more preferably 0.18 to 0.5 parts by mass. When the amount used is 0.005 parts by mass or more (especially 0.18 parts by mass or more), the molecular weight of the acrylic polymer can be easily controlled to be small, the residual stress of the radiation-curable resin layer increases, and the step absorbability is improved. tend to be better.

The reaction between 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, for example, in a solvent with stirring in the presence of a catalyst. Examples of the solvent include those mentioned above. The above catalyst is appropriately selected according to the combination of the first functional group and the second functional group. The reaction temperature in the above reaction is, for example, 5 to 100° C., and the reaction time is, for example, 1 to 36 hours.

The acrylic polymer having a radiation-polymerizable functional group may have a structure derived from a cross-linking agent. For example, the above acrylic polymer can be crosslinked to further reduce low-molecular-weight substances in the radiation-curable resin layer. Also, the weight average molecular weight of the acrylic polymer can be increased. The cross-linking agent cross-links functional groups other than radiation-polymerizable functional groups (for example, first functional groups, second functional groups, or first functional groups and second functional groups). It is. Only one kind of the crosslinking agent may be used, or two or more kinds thereof may be used.

Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, melamine-based cross-linking agents, peroxide-based cross-linking agents, urea-based cross-linking agents, metal alkoxide-based cross-linking agents, metal chelate-based cross-linking agents, and metal salt-based cross-linking agents. Cross-linking agents, carbodiimide-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, amine-based cross-linking agents, silicone-based cross-linking agents, silane-based cross-linking agents and the like. As the cross-linking agent, isocyanate-based cross-linking agents and epoxy-based cross-linking agents are preferable, and isocyanate-based cross-linking agents are more preferable, from the viewpoint of excellent adhesion to the optical semiconductor element and less impurity ions.

Examples of the isocyanate-based cross-linking agent (polyfunctional isocyanate compound) include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; cyclopentylene diisocyanate; , cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate and other alicyclic polyisocyanates; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and aromatic polyisocyanates such as xylylene diisocyanate. Examples of the isocyanate-based cross-linking agent include trimethylolpropane/tolylene diisocyanate adduct, trimethylolpropane/hexamethylene diisocyanate adduct, and trimethylolpropane/xylylene diisocyanate adduct.

The content of the structural part derived from the cross-linking agent is not particularly limited. It is preferably contained in parts by mass or less, more preferably 0.001 to 5 parts by mass, still more preferably 0.01 to 3 parts by mass.

The radiation-curable resin layer may contain components other than the radiation-polymerizable functional group-containing polymer within a range that does not impair the effects of the present invention. Other components include cross-linking accelerators, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, anti-aging agents, fillers (metal powders, organic fillers, inorganic fillers, etc.). ), colorants (pigments, dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, UV absorbers, polymerization inhibitors, granular materials , foil-like materials, and the like. Only one kind of each of the other components may be used, or two or more kinds thereof may be used.

(Radiation non-curable adhesive layer)
As the pressure-sensitive adhesive for forming the radiation non-curable pressure-sensitive adhesive layer, a known or commonly used pressure-sensitive pressure-sensitive adhesive that is not radiation-curable, that is, does not contain a radiation-curable compound, can be used. However, it may contain a small amount of an unavoidable radiation-curing compound that migrates and penetrates from other laminated layers. Examples of the adhesive include acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, mixtures thereof, etc.), silicone adhesives, polyester adhesives, urethane adhesives, polyether system adhesives, polyamide-based adhesives, fluorine-based adhesives, and the like. Among them, acrylic pressure-sensitive adhesives are preferable as the pressure-sensitive adhesive constituting the radiation non-curable pressure-sensitive adhesive layer from the viewpoints of adhesion, weather resistance, cost, and ease of designing the pressure-sensitive adhesive. The radiation non-curable pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive layer composed of an acrylic pressure-sensitive adhesive. Only one kind of the pressure-sensitive adhesive may be used, or two or more kinds thereof may be used.

The acrylic pressure-sensitive adhesive layer contains an acrylic polymer as a base polymer. The above acrylic polymer is a polymer containing an acrylic monomer as a monomer component constituting the polymer. That is, the acrylic polymer contains structural units derived from acrylic monomers. In addition, acrylic polymer may use only 1 type, and may use 2 or more types.

The content of the acrylic polymer in the acrylic pressure-sensitive adhesive layer is not particularly limited, but is preferably 50% by mass or more (for example, 50 to 100% by mass) with respect to 100% by mass of the total amount of the pressure-sensitive adhesive layer. , More preferably 80% by mass or more (eg, 80 to 100% by mass), still more preferably 90% by mass or more (eg, 90 to 100% by mass). When the content is 50% by mass or more, the transparency of the sheet for optical semiconductor element encapsulation is more excellent.

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

Examples of the (meth)acrylic acid esters include hydrocarbon group-containing (meth)acrylic acid esters that may have an alkoxy group. As the hydrocarbon group-containing (meth) acrylic acid ester in the hydrocarbon group-containing (meth) acrylic acid ester which may have an alkoxy group, the above linear or branched aliphatic hydrocarbon group (Meth)acrylic acid alkyl esters, (meth)acrylic acid esters having the above-mentioned alicyclic hydrocarbon group, (meth)acrylic acid esters having the above-mentioned aromatic hydrocarbon group, and the like. The hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group may be used alone or in combination of two or more.

Among the (meth)acrylic acid alkyl esters, linear or branched fatty acids having 1 to 20 carbon atoms (preferably 1 to 14, more preferably 2 to 10, still more preferably 2 to 8) A (meth)acrylic acid alkyl ester having a group hydrocarbon group is preferred. When the number of carbon atoms is within the above range, the glass transition temperature of the acrylic polymer can be easily adjusted, and the adhesion of the radiation non-curable pressure-sensitive adhesive layer can be easily made more appropriate.

Among the (meth)acrylic acid esters having an alicyclic hydrocarbon group, preferred are (meth)acrylic acid esters having a monocyclic aliphatic hydrocarbon ring, more preferably cyclohexyl (meth)acrylate. .

The hydrocarbon group-containing (meth)acrylic acid ester optionally having an alkoxy group includes, among others, a (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group. is preferred, and it is more preferred to contain a (meth)acrylic acid ester having an alicyclic hydrocarbon group. In this case, the radiation non-curable pressure-sensitive adhesive layer has a well-balanced adhesive property, and the optical semiconductor element sealing property is excellent.

In order to appropriately express basic properties such as adhesiveness and adhesion to optical semiconductor elements by the hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group in the radiation non-curable adhesive layer The ratio of the hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group in all the monomer components constituting the acrylic polymer is based on the total amount (100 mol%) of all the monomer components. is preferably 40 mol % or more, more preferably 50 mol % or more. In addition, the above ratio is preferably 95 mol % or less, more preferably 80 mol % or less, from the viewpoint of allowing the other monomer component to be copolymerized and obtaining the effect of the other monomer component.

The ratio of (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group in all the monomer components constituting the acrylic polymer is based on the total amount (100 mol%) of all the monomer components. is preferably 30 mol % or more, more preferably 40 mol % or more. Moreover, the above ratio is preferably 90 mol % or less, more preferably 70 mol % or less.

The ratio of (meth)acrylic acid ester having an alicyclic hydrocarbon group in all monomer components constituting the acrylic polymer is preferably 1 mol% or more with respect to the total amount (100 mol%) of all the monomer components. , more preferably 5 mol % or more. Moreover, the above ratio is preferably 30 mol % or less, more preferably 20 mol % or less.

The acrylic polymer may contain structural units derived from other monomer components such as the polar group-containing monomer for the purpose of improving cohesive strength, heat resistance, and the like. Only one type of each of the other monomer components may be used, or two or more types may be used.

It is preferable that a hydroxy group-containing monomer is included as the polar group-containing monomer constituting the acrylic polymer. In this case, the acrylic polymer and the non-radiation-curable pressure-sensitive adhesive layer have excellent water resistance, and the optical semiconductor element encapsulation sheet is resistant to fogging even when used in a high-humidity environment and has excellent whitening resistance. .

As the hydroxy group-containing monomer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferable, and 2-hydroxyethyl (meth)acrylate is more preferable.

In order to appropriately express basic properties such as adhesiveness and adhesion to optical semiconductor elements by the hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group in the radiation non-curable adhesive layer The proportion of the polar group-containing monomer in the total monomer components (100 mol %) constituting the acrylic polymer is preferably 5 to 50 mol %, more preferably 10 to 40 mol %. In particular, the ratio of the hydroxy group-containing monomer is preferably within the above range from the viewpoint of improving the water resistance of the radiation non-curable pressure-sensitive adhesive layer.

The acrylic polymer may contain a structural unit derived from a polyfunctional monomer copolymerizable with the monomer components constituting the acrylic polymer in order to form a crosslinked structure in the polymer skeleton. As the polyfunctional monomer, in addition to the polyfunctional (meth)acrylate, epoxy (meth)acrylate (e.g., polyglycidyl (meth)acrylate), polyester (meth)acrylate, urethane (meth)acrylate, etc. Examples thereof include monomers having a (meth)acryloyl group and other reactive functional groups. Only one kind of the polyfunctional monomer may be used, or two or more kinds thereof may be used.

In order to appropriately express basic properties such as adhesiveness and adhesion to optical semiconductor elements by the hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group in the radiation non-curable adhesive layer The proportion of the polyfunctional monomer in the total monomer components (100 mol %) constituting the acrylic polymer is preferably 40 mol % or less, more preferably 30 mol % or less.

The acrylic polymer may have a structure derived from the cross-linking agent. For example, the above acrylic polymer can be crosslinked to further reduce low-molecular-weight substances in the radiation-curable resin layer. Also, the weight average molecular weight of the acrylic polymer can be increased. Only one kind of the crosslinking agent may be used, or two or more kinds thereof may be used.

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

The weight average molecular weight of the acrylic polymer is not particularly limited, but is preferably 100,000 to 3,000,000, more preferably 200,000 to 2,500,000. When the weight-average molecular weight is within the above range, the adhesion of the radiation non-curable pressure-sensitive adhesive layer is well-balanced, and the encapsulation of the optical semiconductor element is more excellent. The weight average molecular weight is measured by gel permeation chromatography (GPC) and calculated by polystyrene conversion.

The non-radiation-curable pressure-sensitive adhesive layer may contain components other than the base polymer as long as the effects of the present invention are not impaired. Examples of the other components include those exemplified and explained as other components that the radiation-curable resin layer may contain. Only one kind of each of the other components may be used, or two or more kinds thereof may be used.

(sealing part)
In the sealing portion, the radiation-noncurable adhesive layer and the radiation-curable resin layer are laminated. The non-radiation-curable pressure-sensitive adhesive layer and the radiation-curable resin layer may be directly laminated with no other layer interposed therebetween, or may be laminated with another layer interposed therebetween. Even in the case where the sealing portion has a structure in which the radiation non-curable adhesive layer and the radiation curable resin layer are directly laminated, it has the radiation polymerizable functional group in the radiation curable resin layer. Since the polymer hardly migrates to the non-radiation-curable pressure-sensitive adhesive layer, the sheet for encapsulating optical semiconductor elements of the present invention has excellent encapsulating properties for optical semiconductor elements and suppresses stickiness on the sides after curing.

Each of the radiation non-curable pressure-sensitive adhesive layer and the radiation curable resin layer may be a single layer, or may be multiple layers that are the same or different in composition, thickness, and the like. When the sealing portion has a plurality of at least one of the non-radiation-curable pressure-sensitive adhesive layer and the radiation-curable resin layer, the plurality of layers may be continuously laminated, with other layers interposed therebetween. It may be laminated.

The sealing layer preferably has the non-radiation-curable pressure-sensitive adhesive layer on the surface of the sealing portion that faces the optical semiconductor element when the optical semiconductor element is sealed. Specifically, the non-radiation-curable pressure-sensitive adhesive layer is the sheet surface for optical semiconductor element encapsulation that is on the optical semiconductor element side when encapsulating the optical semiconductor element (when a release liner is provided, the sheet excluding the release liner surface). When the radiation non-curable adhesive layer is located on the surface, when the optical semiconductor element encapsulating sheet encapsulates the optical semiconductor element, the radiation non-curable adhesive layer adheres to the optical semiconductor element and the substrate. Direct contact is achieved, and excellent encapsulation of the optical semiconductor element is obtained.

The radiation curable resin layer is preferably thicker than the radiation non-curable adhesive layer. By having such a configuration, the adhesion after curing of the radiation curable resin layers in the adjacent optical semiconductor devices is lower than the high adhesion between the radiation non-curable adhesive layers in the adjacent optical semiconductor devices in the tiling state. Since the adhesiveness is dominant, the adhesiveness between the sealing portions is even lower, and when the adjacent optical semiconductor devices are separated from each other, the damage of the sheet and adhesion of the sheets of the adjacent optical semiconductor devices are much less likely to occur. Further, when dicing the optical semiconductor device after sealing the optical semiconductor element with the optical semiconductor element encapsulating sheet, stickiness of the diced portion can be further suppressed, and an optical semiconductor device having a good appearance can be produced. can be done. In addition, when it has multiple said radiation curable resin layers or said radiation non-curable adhesive layers, the said thickness is the total thickness (total thickness) of a multiple layer.

The thickness (total thickness) of the radiation-curable resin layer is preferably the thickest among all the layers constituting the sheet for optical semiconductor element encapsulation. In particular, the sheet for encapsulating optical semiconductor elements preferably includes a radiation-curable resin layer having the largest thickness among all the layers constituting the sheet for encapsulating optical semiconductor elements. A layer obtained by directly laminating a plurality of layers having the same composition is considered as one layer. Moreover, when it has two or more thickest layers, any layer corresponds to the thickest layer.

For example, in the sheet 1 for encapsulating an optical semiconductor element shown in FIG. The radiation curable resin layer 31 is positioned on the base material portion 2 side within the sealing portion 3 . The radiation non-curable pressure-sensitive adhesive layer 32 is located on the optical semiconductor element side surface in the sealing portion 3, and is on the opposite side of the optical semiconductor element encapsulating sheet 1 from the base material portion 2 except for the release liner 4. located on the surface of The radiation curable resin layer 31 is thicker than the radiation non-curable adhesive layer 32 and is the thickest layer in the encapsulating portion 3 and the optical semiconductor element encapsulating sheet 1 .

The thickness (total thickness) of the radiation-curable resin layer is preferably 20 to 800 μm, more preferably 30 to 700 μm, still more preferably 50 to 600 μm. When the thickness is 20 μm or more, when the adjacent optical semiconductor devices are separated from each other, the damage of the sheet and the adhesion of the sheets of the adjacent optical semiconductor devices are much less likely to occur. When the thickness is 800 μm or less, the thickness of the sealing portion can be reduced, and the optical semiconductor device can be made thinner.

The ratio of the thickness (total thickness) of the radiation-curable resin layer to 100% of the total thickness of the optical semiconductor element encapsulating sheet (excluding the release liner and surface protective film) is 5 to 90%. It is preferably 10 to 85%, still more preferably 40 to 80%. When the ratio is 5% or more, when the adjacent optical semiconductor devices are separated from each other, damage to the sheet and adhesion of the sheets of the adjacent optical semiconductor devices are more unlikely to occur. When the thickness is 90% or less, the thickness of the sealing portion can be reduced, and the optical semiconductor device can be made thinner.

After curing, the radiation-curable resin layer preferably has a hardness of 1.2 MPa or higher, more preferably 1.4 MPa or higher, and still more preferably 2 0 MPa or more, more preferably 15.0 MPa or more, and particularly preferably 50.0 MPa or more. The hardness by the nanoindentation method is obtained by continuously measuring the load applied to the indenter and the depth of indentation during loading and unloading when the indenter is pressed into the target surface. Obtained from the indentation depth curve. When the hardness is 1.2 MPa or more, the radiation-curable resin layer has an appropriate hardness after curing. Adhesion of the sheet of the optical semiconductor device to be performed is much less likely to occur.

The radiation-curable resin layer preferably has a hardness of less than 1.4 MPa, more preferably 1.3 MPa or less, and even more preferably 1 .2 MPa or less. When the hardness is less than 1.4 MPa, the radiation-curable resin layer is relatively soft before curing, and is excellent in encapsulating properties when encapsulating an optical semiconductor element.

In the radiation-curable resin layer, the ratio of hardness after curing to before curing [after curing/before curing] is preferably 1.0 or more with respect to the hardness measured by the nanoindentation method at a temperature of 23° C. in the cross section of the layer. , more preferably 1.3 or more, still more preferably 5.0 or more, and particularly preferably 10.0 or more. When the above ratio is 1.3 or more, the encapsulating portion is excellent in encapsulating properties of the optical semiconductor element before curing of the radiation-curable resin layer, and stickiness of the side surface is further suppressed after curing.

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, still more preferably 40 μm or less, even more preferably 10 μm or less, and even more preferably 10 μm or less. is 4 μm or less, particularly preferably 1 μm or less. When the arithmetic average height Sa is 85 μm or less, the surface roughness of the side surface of the cured sealing layer, which is the layer after curing of the exposed radiation-curable resin layer, is small, and when separating the adjacent optical semiconductor devices, the sheet Chipping of the optical semiconductor device and adhesion of the sheet of the adjacent optical semiconductor device are much less likely to occur.

The thickness of the radiation non-curable pressure-sensitive adhesive layer located on the surface of the sheet for optical semiconductor element encapsulation (that is, the surface of the sealing portion) is preferably 1 μm or more, more preferably 4 μm or more, and even more preferably. is 15 μm or more. When the thickness is 1 μm or more, the adhesiveness of the optical semiconductor element encapsulating sheet to the optical semiconductor element or the substrate is excellent. The thickness is preferably 500 μm or less, more preferably 300 μm or less, still more preferably 200 μm or less. When the thickness is 500 μm or less, when the adjacent optical semiconductor devices are separated from each other, damage to the sheet and adhesion of the sheets of the adjacent optical semiconductor devices are less likely to occur. Further, when the optical semiconductor device is diced, stickiness of the diced portion can be further suppressed, and an optical semiconductor device with a good appearance can be manufactured.

The sealing portion may have a layer other than the radiation-curable resin layer and the non-radiation-curable pressure-sensitive adhesive layer. However, the ratio of the total thickness of the radiation-curable resin layer and the non-radiation-curable pressure-sensitive adhesive layer to 100% of the thickness of the sealing portion is preferably 70% or more, more preferably 80%. % or more, more preferably 90% or more, particularly preferably 96% or more.

The sealing portion may include a layer containing a coloring agent. By having such a configuration, when the optical semiconductor device is applied to a display by tiling, color mixing of light emitted from each optical semiconductor element is suppressed when the optical semiconductor device is used, and the optical semiconductor device is improved. The appearance of the display can be adjusted when not in use. The layer containing the coloring agent may have only one layer, or may have two or more layers.

The layer containing the colorant may be the radiation-curable resin layer, the non-radiation-curable pressure-sensitive adhesive layer, or other layers. The curable pressure-sensitive adhesive layer is preferably a layer containing a colorant, and the radiation non-curable pressure-sensitive adhesive layer is more preferably a layer containing a colorant.

As the coloring agent, a black coloring agent is preferable. As the black colorant, known or commonly used colorants (pigments, dyes, etc.) for exhibiting black color can be used. For example, carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, , pine smoke, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide , chromium complexes, anthraquinone colorants, and zirconium nitride. Only one type of black colorant may be used, or two or more types may be used. Alternatively, a coloring agent that functions as a black coloring agent may be used by combining coloring agents exhibiting colors other than black.

<Base material part>
The substrate portion serves as a support for the sealing portion, and the sheet for optical semiconductor element encapsulation has excellent handleability by including the substrate portion. The base material portion may be a single layer, or may be a plurality of layers that are the same or different in composition, thickness, and the like. When the base material portion is a multilayer, each layer may be bonded with another layer such as an adhesive layer. In addition, when the optical semiconductor element is sealed using the optical semiconductor element encapsulating sheet, the base material layer used for the base material part is the part that is attached to the substrate including the optical semiconductor element together with the sealing part. A release liner that is peeled off when the optical semiconductor element encapsulating sheet is used (attached) and a surface protection film that only protects the surface of the base material are not included in the "base material".

Examples of the substrate layer constituting the substrate portion include glass and plastic substrates (especially plastic films). Examples of the resin constituting the plastic substrate include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymerized polypropylene, block copolymerized polypropylene, and homopolypropylene. , polybutene, polymethylpentene, ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene- Polyolefin resins such as propylene copolymers, cyclic olefin polymers, ethylene-butene copolymers, and ethylene-hexene copolymers; polyurethanes; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT); Polycarbonate; polyimide resin; polyether ether ketone; polyether imide; polyamide such as aramid and wholly aromatic polyamide; polyphenyl sulfide; fluorine resin; silicone resin; acrylic resin such as polymethyl methacrylate (PMMA); polysulfone; polyarylate; Only one kind of the above resin may be used, or two or more kinds thereof may be used.

The substrate layer may be various optical films such as an antireflection (AR) film, a polarizing plate, and a retardation plate. When the substrate part has an optical film, the optical semiconductor element encapsulating sheet can be applied as it is to the optical member.

The plastic film preferably contains a polyester resin and/or a polyimide resin as a main component (a component having the highest mass ratio among constituent resins). By having such a structure, the sheet for optical semiconductor element encapsulation has excellent heat resistance, the thermal expansion of the sheet for optical semiconductor element encapsulation can be suppressed in a high temperature environment, and the dimensional stability is improved. In addition, since rigidity as a sheet can be imparted, handleability and holdability are improved.

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

It is preferable that the base material includes a plastic film containing a polyester resin and/or a polyimide resin as a main component, and an optical film. Optical films such as polarizing plates generally tend to be inferior in supportability and handleability, and by using them in combination with the above plastic film, the advantages of both can be utilized. In this case, it is particularly preferable that the plastic film is located on the side of the sealing portion in the base portion.

It is preferable that the substrate part has a layer having antiglare properties and/or antireflection properties. The layer having antiglare properties and/or antireflection properties can be formed, for example, by subjecting at least one surface of the base material layer to antiglare treatment and/or antireflection treatment, thereby forming the antiglare treatment layer or antireflection treatment layer. can get. The antiglare treatment layer and the antireflection treatment layer may be the same layer or different layers. Antiglare treatment and antireflection treatment can be carried out by known or common methods.

The surface of the base material portion on the side provided with the sealing portion is subjected to, for example, corona discharge treatment, plasma treatment, sand mat processing, ozone exposure treatment, and so on for the purpose of enhancing adhesion, retention, etc. with the sealing portion. Physical treatments such as flame exposure treatment, high voltage shock exposure treatment, and ionizing radiation treatment; chemical treatments such as chromic acid treatment; and surface treatments such as easy adhesion treatment with a coating agent (undercoat). It is preferable that the surface treatment for enhancing adhesion is applied to the entire surface of the base member on the sealing portion side.

In the optical semiconductor element encapsulating sheet 1 shown in FIG. glued together through The surface of the optical film 21 facing the plastic film 23 is subjected to antiglare treatment and antireflection treatment.

The thickness of the base material is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of function as a support and excellent scratch resistance of the surface. The thickness of the base material is preferably 300 μm or less, more preferably 200 μm or less, from the viewpoint of better transparency.

<Release liner>
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 encapsulating sheet is attached to the substrate on which the optical semiconductor element is arranged.

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

The thickness of the release liner is, for example, 10-200 μm, preferably 15-150 μm, more preferably 20-100 μm. When the thickness is 10 μm or more, the release liner is less likely to break due to cutting during processing. When the thickness is 200 μm or less, the release liner can be easily peeled off from the sealing portion during use.

<Sheet for optical semiconductor element encapsulation>
The ratio of the total thickness of the base portion and the sealing portion in the optical semiconductor element encapsulating sheet is the thickness of the optical semiconductor element encapsulating sheet (excluding the release liner and the surface protective film) With respect to 100%, it is preferably 80% or more, more preferably 90% or more. Moreover, it is preferable that the ratio of the thickness from the surface of the substrate portion to the surface of the sealing portion, including the substrate portion and the sealing portion, is within the above range.

The total thickness of the base portion and the sealing portion in the sheet for optical semiconductor element encapsulation is preferably 100 to 900 μm, more preferably 200 to 800 μm. In addition, it is preferable that the thickness from the surface of the substrate portion to the surface of the sealing portion, including the substrate portion and the sealing portion, is within the above range.

One embodiment of the method for producing the sheet for optical semiconductor element encapsulation of the present invention will be described. For example, the sheet 1 for optical semiconductor element encapsulation shown in FIG. 1 can be produced by the following method. First, the radiation-curable resin layer 31 is formed on the plastic film 23 that constitutes the base material portion 2 . The radiation-curable resin layer 31 is formed by applying a resin composition for forming the radiation-curable resin layer 31 to one surface of the plastic film 23 to form a resin composition layer, and then removing the solvent by heating, heat curing, or the like. can be prepared by curing the resin composition layer by curing other than radiation irradiation. When the thickness of the radiation-curable resin layer 31 is increased, a radiation-curable resin layer prepared in the same manner on the release-treated surface of the release liner is added to the radiation-curable resin layer formed on the plastic film 23. It may be laminated on top of it.

The resin composition forming the radiation-curable resin layer may be in any form as long as it does not impair the radiation polymerizability of the radiation-polymerizable functional group. For example, the adhesive composition may be emulsion type, solvent type (solution type), thermal melting type (hot melt type), or the like. Among them, the solvent type is preferable because it is easy to obtain a pressure-sensitive adhesive layer with excellent productivity.

The resin composition may contain the crosslinking agent and the photopolymerization initiator (photoinitiator) in addition to the polymer having a radiation-polymerizable functional group and the other components. When the above-mentioned cross-linking agent is included, cross-linking by the above-mentioned cross-linking agent proceeds when the above-mentioned resin composition layer is heated to form a radiation-curable resin layer. Moreover, when the photopolymerization initiator is contained, the polymerization of the radiation-polymerizable functional group is accelerated when the radiation-curable resin layer is cured. Each of the crosslinking agent and the photopolymerization initiator may be used alone or in combination of two or more.

On the other hand, a non-radiation-curable adhesive layer 32 is formed on the release-treated surface of the release liner 4 separately prepared. The radiation non-curable pressure-sensitive adhesive layer 32 is formed by applying a pressure-sensitive adhesive composition for forming the radiation non-curable pressure-sensitive adhesive layer 32 onto the release-treated surface of the release liner 4 to form a pressure-sensitive adhesive composition layer, followed by heating. It can be prepared by removing the solvent and curing with and solidifying the pressure-sensitive adhesive composition layer. Then, the radiation non-curable adhesive layer is laminated on the radiation curable resin layer. Thus, a laminate having a configuration of [plastic film 23/radiation-curable resin layer 31/radiation non-curable adhesive layer 32/release liner 4] is obtained.

The pressure-sensitive adhesive composition forming the radiation non-curable pressure-sensitive adhesive layer may be in any form. For example, the pressure-sensitive adhesive composition may be an emulsion type, a solvent type (solution type), an active energy ray-curable type, a heat-melting type (hot-melt type), or the like. Among them, solvent-type and active-energy-ray-curable adhesive compositions are preferred because they facilitate the formation of an adhesive layer with excellent productivity.

On the other hand, a laminate of the optical film 21 and the adhesive layer 22 is produced. Specifically, for example, the adhesive layer 22 is formed on the release-treated surface of a separately prepared release liner in the same manner as the radiation non-curable adhesive layer 32, and then the optical film 21 is placed on the adhesive layer 22. It can be manufactured by laminating. Then, the release liner is peeled off to expose the pressure-sensitive adhesive layer 22, which is attached to the surface of the plastic film 23 of the laminate on which the radiation-curable resin layer 31 is not formed. As a coating method for the resin composition or the pressure-sensitive adhesive composition, for example, a known or commonly used coating method can be employed, and examples thereof include roll coating, screen coating, gravure coating, and the like. Lamination of various layers can be performed using a known roller or laminator. Thus, the sheet 1 for optical semiconductor element encapsulation shown in FIG. 1 can be produced.

In addition, the sheet for optical semiconductor element encapsulation of the present invention is not limited to the method described above. The resin layer and the non-radiation-curable pressure-sensitive adhesive layer can be appropriately combined and laminated in sequence.

Using the sheet for encapsulating an optical semiconductor device of the present invention, the encapsulating portion of the sheet for encapsulating an optical semiconductor device of the present invention is attached to a substrate on which an optical semiconductor element is arranged, and the optical semiconductor element is formed by the encapsulating portion. can be sealed to obtain an optical semiconductor device. Specifically, first, the release liner is peeled off from the sheet for optical semiconductor element encapsulation of the present invention to expose the encapsulation portion. Then, the optical semiconductor element encapsulation of the present invention is applied to the substrate surface on which the optical semiconductor elements are arranged, of an optical member comprising a substrate and optical semiconductor elements (preferably a plurality of optical semiconductor elements) arranged on the substrate. When the optical member includes a plurality of optical semiconductor elements, the sealing portion is further arranged so that the gap between the plurality of optical semiconductor elements is filled with the sealing portion, and a plurality of of optical semiconductor elements are collectively sealed. Thus, an optical semiconductor element can be sealed using the sheet for optical semiconductor device encapsulation of the present invention. Moreover, you may seal an optical-semiconductor element by bonding together under a pressure-reduced environment or pressurizing using the sheet|seat for optical-semiconductor-device sealing of this invention. Examples of such a method include the methods disclosed in JP-A-2016-29689 and JP-A-6-97268.

[Optical semiconductor device]
An optical semiconductor device can be produced using the sheet for optical semiconductor element encapsulation of the present invention. An optical semiconductor device manufactured using the sheet for optical semiconductor element encapsulation of the present invention comprises a substrate, an optical semiconductor element disposed on the substrate, and an optical semiconductor element of the present invention for sealing the optical semiconductor element. and a cured product obtained by curing the sheet for sealing. The cured product is a cured product obtained by curing the sheet for encapsulating optical semiconductor elements of the present invention by irradiation with radiation. and a cured sealing layer cured by.

Examples of the optical semiconductor elements include light-emitting diodes (LEDs) such as blue light-emitting diodes, green light-emitting diodes, red light-emitting diodes, and ultraviolet light-emitting diodes.

In the above optical semiconductor device, the optical semiconductor element encapsulating sheet of the present invention has excellent followability to irregularities when the optical semiconductor elements are convex portions and the gaps between the plurality of optical semiconductor elements are concave portions. It is preferable to collectively seal a plurality of optical semiconductor elements because of its excellent embeddability.

FIG. 2 shows an embodiment of an optical semiconductor device using the optical semiconductor element sealing sheet 1 shown in FIG. An optical semiconductor device 10 shown in FIG. 1'. The cured product 1' of the optical semiconductor element encapsulating sheet is a cured sealing layer 31 formed by peeling the release liner 4 from the optical semiconductor element encapsulating sheet 1 and curing the radiation curable resin layer 31 by irradiation with radiation. ' is formed. The plurality of optical semiconductor elements 6 are collectively sealed in the sealing portion. The non-radiation-curable adhesive layer 32 in the sealing portion adheres closely to the optical semiconductor elements 6 and the substrate 5 by following the uneven shape formed by the plurality of optical semiconductor elements 6 , and embeds the optical semiconductor elements 6 .

In the optical semiconductor device 10 shown in FIG. 2, the optical semiconductor element 6 is completely embedded and sealed in the radiation non-curable adhesive layer 32, and is indirectly cured by the cured sealing layer 31'. is sealed in The optical semiconductor device is not limited to such an aspect, and a part of the optical semiconductor element 6 protrudes from the radiation non-curable adhesive layer 32, and the part is embedded in the cured sealing layer 31'. The optical semiconductor element 6 may be completely embedded and sealed by the radiation non-curable adhesive layer 32 and the cured sealing layer 31'.

As described above, the optical semiconductor device seals the optical semiconductor element with the radiation non-curable adhesive layer and the cured sealing layer that is the cured product of the radiation curable resin layer. For this reason, the optical semiconductor element is in close contact with the sealing portion, and the sealing property of the optical semiconductor element is excellent, and the adhesiveness of the side surface of the cured sealing layer is low. When the optical semiconductor devices are separated from each other, they can be easily separated, and damage to the sheet and adherence of the adjacent optical semiconductor device sheets to each other are less likely to occur.

The optical semiconductor device may be formed by tiling individual optical semiconductor devices. That is, the optical semiconductor device may be a plurality of optical semiconductor devices arranged in a tile shape in a planar direction.

FIG. 3 shows an embodiment of an optical semiconductor device manufactured by arranging a plurality of optical semiconductor devices. In the optical semiconductor device 20 shown in FIG. 3, a total of 16 optical semiconductor devices 10, ie, four in the vertical direction and four in the horizontal direction, are arranged (tiled) in a planar direction. At the boundary 20a between two adjacent optical semiconductor devices 10, the optical semiconductor devices 10 are adjacent to each other. On the other side, the resin that is missing on the side surface of the sealing portion is less likely to adhere to the other side.

The optical semiconductor device is preferably a backlight for a liquid crystal screen, and more preferably a full-surface direct type backlight. An image display device can be obtained by combining the backlight and the display panel. When the optical semiconductor device is a backlight for a liquid crystal screen, the optical semiconductor element is an LED element. For example, in the backlight, a metal wiring layer for sending light emission control signals to each LED element is laminated on the substrate. The LED elements that emit red (R), green (G), and blue (B) lights are alternately arranged on the substrate of the display panel via metal wiring layers. The metal wiring layer is made of metal such as copper, and reflects the light emitted from each LED element to reduce the visibility of the image. In addition, the light emitted from each LED element of each color of RGB is mixed, and the contrast is lowered.

Further, the optical semiconductor device is preferably a self-luminous display device. An image display device can be obtained by combining the self-luminous display device and, if necessary, a display panel. When the optical semiconductor device is a self-luminous display device, the optical semiconductor element is an LED element. Examples of the self-luminous display device include an organic electroluminescence (organic EL) display device. For example, in the self-luminous display device, metal wiring layers for sending light emission control signals to the LED elements are laminated on the substrate. The LED elements that emit red (R), green (G), and blue (B) lights are alternately arranged on the substrate via metal wiring layers. The metal wiring layer is made of metal such as copper, and displays each color by adjusting the degree of light emission of each LED element.

The sheet for encapsulating an optical semiconductor element of the present invention has an optical semiconductor device that is used by folding, for example, a foldable image display device (flexible display) (particularly, a foldable image display device (foldable display)). It can be used for an optical semiconductor device. Specifically, it can be used for a foldable backlight, a foldable self-luminous display device, and the like.

Since the sheet for encapsulating an optical semiconductor element of the present invention is excellent in the embedding property of an optical semiconductor element, it is preferably used both when the optical semiconductor device is a mini LED display device and when it is a micro LED display device. can be done.

[Method for manufacturing an optical semiconductor device]
The optical semiconductor device comprises, for example, a substrate, an optical semiconductor element disposed on the substrate, and the radiation-curable resin layer of the sheet for optical semiconductor element encapsulation of the present invention, which seals the optical semiconductor element. and a dicing step of obtaining an optical semiconductor device by dicing the laminate comprising the cured product. The cured product is a cured product obtained by curing the sheet for encapsulating optical semiconductor elements of the present invention by irradiation with radiation. and a cured sealing layer cured by.

When the radiation-curable resin layer is cured by irradiating with radiation, curing is inhibited on the side where oxygen exists, and curing tends to be insufficient. On the other hand, according to the manufacturing method including the dicing step, a laminate including a cured product of a sheet for optical semiconductor element encapsulation including a cured sealing layer obtained by curing the radiation-curable resin layer by irradiation with radiation In the above dicing step, by cutting off and removing the side end portions where the curing is insufficient, it is possible to obtain an optical semiconductor device in which the regions where the adhesiveness is lowered due to the sufficient curing are exposed on the side surfaces. In the optical semiconductor device manufactured in this manner, since the adhesiveness of the side surface of the radiation-curable resin layer after curing is sufficiently lowered, when the adjacent optical semiconductor devices are separated in the tiling state, the sheet is not damaged. Also, adhesion of sheets of adjacent optical semiconductor devices is less likely to occur.

The manufacturing method further includes irradiating a laminate comprising the substrate, an optical semiconductor element disposed on the substrate, and the optical semiconductor element sealing sheet for sealing the optical semiconductor element with radiation. A radiation irradiation step of curing the radiation-curable resin layer to obtain the cured product may be provided.

In the manufacturing method, before the radiation irradiation step, the optical semiconductor element encapsulating sheet is attached to the optical semiconductor element provided on the substrate, and the optical semiconductor element is sealed with the sealing portion. You may provide the sealing process which carries out.

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 in a plane direction. A method for manufacturing the optical semiconductor device 10 shown in FIG. 2 and the optical semiconductor device 20 shown in FIG. 3 will be described below with appropriate reference.

(sealing process)
In the sealing step, the sheet for optical semiconductor element encapsulation of the present invention is attached to the substrate on which the optical semiconductor element is arranged, and the optical semiconductor element is sealed by the sealing portion. In the sealing step, specifically, as shown in FIG. is arranged so as to face the surface on which the optical semiconductor element encapsulation sheet 1 is arranged, and the optical semiconductor element encapsulating sheet 1 is attached to the surface of the substrate 5 on which the optical semiconductor element 6 is arranged, and the optical semiconductor element 6 is sealed as shown in FIG. Embed in the stop part 3. As shown in FIG. 4, the substrate 5 used for bonding extends wider in the planar direction than the substrate 5 in the optical semiconductor device 10 shown in FIG. is not placed. Moreover, the sheet 1 for encapsulating an optical semiconductor element to be bonded extends in a plane direction wider than the substrate 5 used for bonding. That is, the area of the surface facing the substrate 5 of the optical semiconductor element encapsulating sheet 1 bonded in the sealing step is the surface of the optical semiconductor element encapsulating sheet 1 that is bonded in the sealing step larger than the area of In the laminate of the optical-semiconductor element encapsulating sheet 1 and the substrate 5, the area used for the optical semiconductor device is sufficiently cured in the subsequent radiation irradiation step, and the optical-semiconductor element encapsulating sheet 1 and the substrate 5 This is because the vicinity of the edge of the substrate 5 which may be insufficiently hardened is diced and removed in a later dicing process.

The temperature during the bonding is, for example, within the range of room temperature to 110°C. In addition, pressure may be reduced or pressurized during the bonding. It is possible to suppress the formation of a gap between the sealing portion and the substrate or the optical semiconductor element by depressurization or pressurization. Moreover, in the said sealing process, it is preferable to bond together the sheet|seat for optical-semiconductor element sealing under pressure reduction, and to pressurize after that. The pressure for decompression is, for example, 1 to 100 Pa, and the decompression time is, for example, 5 to 600 seconds. Further, the pressure when pressurizing is, for example, 0.05 to 0.5 MPa, and the pressure reduction time is, for example, 5 to 600 seconds.

(Radiation irradiation step)
In the radiation irradiation step, the laminate (for example, the laminate obtained in the sealing step) in which the sheet for encapsulating the optical semiconductor element is attached to 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, as shown in FIG. 6, the radiation-curable resin layer 31 is cured to form a cured sealing layer 31′, and the cured product 1 of the optical semiconductor element sealing sheet 1 is formed. ' is obtained. Examples of the radiation include electron beams, ultraviolet rays, α rays, β rays, γ rays, and X rays, as described above. Among them, ultraviolet rays are preferred. The temperature during irradiation is, for example, within the range of room temperature to 100° C., and the irradiation time is, for example, 1 minute to 1 hour.

(Dicing process)
In the dicing step, a laminate comprising a substrate, an optical semiconductor element arranged on the substrate, and a cured product of the optical semiconductor element sealing sheet of the present invention that seals the optical semiconductor element (for example, , the laminate that has undergone the radiation irradiation step) is diced. Here, in the laminate to be subjected to the dicing step, the cured product 1' of the optical semiconductor element encapsulating sheet and the substrate 5 extend wider in the planar direction than the finally obtained optical semiconductor device 10, as described above. there is In the dicing step, the cured product of the optical semiconductor element encapsulation sheet and the side edges of the substrate are removed by dicing. Specifically, dicing is performed at the position of the dashed line shown in FIG. 7 to remove the side edge. The dicing can be performed by a known or commonly used method, for example, a method using a dicing blade or by laser irradiation. Thus, for example, the optical semiconductor device 10 shown in FIG. 2 can be manufactured.

Here, in the above-described production method, it is important to perform dicing in a state in which the radiation-curable resin layer obtained through the above-described radiation irradiation step, for example, is cured. When dicing is performed in a state in which the radiation-curable resin layer is not cured, when the side edges of the optical semiconductor element encapsulation sheet are pulled apart after dicing and removed, the side edges to be removed and the remaining light The adhesiveness of the radiation-curable resin layers in the semiconductor device is high, and the radiation-curable resin layers in the remaining optical semiconductor device are in close contact with each other, causing damage to the radiation-curable resin layer. A problem may arise that a part of the radiation-curable resin layer is transferred and attached. On the other hand, by providing the dicing step in which dicing is performed in a cured state of the radiation-curable resin layer, the radiation-curable resin layer is cured to form a cured sealing layer. The adhesiveness is low, and the occurrence of the above problems can be suppressed.

In addition, when the radiation-curable resin layer is cured by irradiating it with radiation, curing is inhibited on the side where oxygen exists, and curing tends to be insufficient. On the other hand, according to the manufacturing method including the dicing step, in the cured state of the radiation-curable resin layer, the side surface is formed by cutting off and removing the edge portion that is insufficiently cured in the dicing step. It is possible to obtain an optical semiconductor device which is sufficiently cured and whose adhesion is lowered. In the optical semiconductor device manufactured in this way, the adhesiveness of the side surface is sufficiently lowered after the radiation-curable resin layer is cured. Defects and adhesion of sheets of adjacent optical semiconductor devices are less likely to occur. On the other hand, if the dicing step is not provided, the side surfaces that are insufficiently cured will come into contact with the adjacent optical semiconductor devices during tiling. are in close contact with each other, causing defects in the radiation-curable resin layer in one optical semiconductor device, or part of the radiation-curable resin layer in one optical semiconductor device being transferred and attached to the other optical semiconductor device. It is easy to cause problems such as slipping.

(tiling process)
In the tiling step, the plurality of optical semiconductor devices obtained in the dicing step are arranged and tiled so as to be in contact with each other in the plane direction. Thus, for example, the optical semiconductor device 20 shown in FIG. 3 can be manufactured. The optical semiconductor device obtained by tiling is excellent in encapsulation of the optical semiconductor element, but when the adjacent optical semiconductor devices are separated from each other, the sheets are less likely to be damaged or the sheets of the adjacent optical semiconductor devices to adhere.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples.

Example 1
<TAC film/binder adhesive layer>
As monomer components, 2-ethylhexyl acrylate (2EHA) 69.7 parts by mass, 2-methoxyethyl acrylate (MEA) 10 parts by mass, 2-hydroxyethyl acrylate (HEA) 13 parts by mass, N-vinyl-2- Pyrrolidone (NVP) 6 parts by mass, N-hydroxyethyl acrylamide (HEAA) 1.3 parts by mass, 2,2'-azobisisobutyronitrile 0.1 parts by mass as a polymerization initiator, and ethyl acetate 200 as a polymerization solvent The parts by mass were put into a separable flask and stirred for 1 hour while nitrogen gas was introduced. After oxygen was removed from the polymerization system in this way, the temperature was raised to 63° C. and the mixture was allowed to react for 10 hours. Based on 100 parts by mass of the acrylic polymer, 0.2 parts by mass of an isocyanate-based cross-linking agent (trade name “Takenate D110N”, manufactured by Mitsui Chemicals, Inc.) as a cross-linking agent, and γ-glycidoxypropyl as a silane coupling agent. Trimethoxysilane (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.15 parts by mass, polyol obtained by adding propylene oxide to ethylenediamine as a cross-linking accelerator (trade name “EDP-300”, manufactured by ADEKA Co., Ltd. ) was added to prepare a pressure-sensitive adhesive composition (solution). Next, the pressure-sensitive adhesive composition (solution) is applied onto the release-treated surface of a release liner (separator) (trade name “MRF38”, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying is 25 μm. and dried by heating at 60° C. for 1 minute and at 155° C. for 1 minute under normal pressure to obtain a double-sided pressure-sensitive adhesive sheet as a binder pressure-sensitive adhesive layer. Then, using a hand roller, a binder The adhesive surface of the adhesive layer was adhered so as not to contain air bubbles. Thus, a laminate having a configuration of [TAC film/binder pressure-sensitive adhesive layer/release liner] was produced.

<PET film/ultraviolet curable adhesive layer/radiation non-curable adhesive layer>
(Ultraviolet curable adhesive layer)
Butyl acrylate (BA) 189.77 parts by mass, cyclohexyl acrylate (CHA) 38.04 parts by mass, 2-hydroxyethyl acrylate (HEA) 85.93 parts by mass, 2,2'-azo as a polymerization initiator 0.94 parts by mass of bisisobutyronitrile and 379.31 parts by mass of methyl ethyl ketone as a polymerization solvent were placed in a 1 L round bottom separable flask, a separable cover, a separating funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, The mixture was placed in a polymerization experimental apparatus equipped with a vacuum seal, a stirring rod, and a stirring blade, and the mixture was replaced with nitrogen at room temperature for 6 hours while stirring. Thereafter, polymerization was carried out by holding at 65° C. for 4 hours and at 75° C. for 2 hours while stirring under flowing nitrogen to obtain a resin solution.
The resulting resin solution was then cooled to room temperature. After that, 5.74 parts by mass of 2-isocyanatoethyl methacrylate (MOI) (trade name “Karenzu MOI”, manufactured by Showa Denko KK) is added to the resin solution as a compound having a polymerizable carbon-carbon double bond. rice field. Further, 0.03 part by mass of dibutyltin dilaurate (IV) (manufactured by Fuji Film 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.
Based on 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 2,2-dimethoxy- 1 part by mass of 1,2-diphenyl-1-one (trade name “omnirad 651”, manufactured by IGM Resins Italia Srl) was mixed. Using toluene as a diluent solvent, the solid content was adjusted to 20 to 40% by mass to obtain an adhesive solution (1).

This adhesive solution (1) was applied to the treated surface of a PET film (trade name “T912E75 (UE80-)”, manufactured by Mitsubishi Chemical Corporation, thickness 75 μm) so that the thickness after drying was 112.5 μm. and dried by heating at 50° C. for 1 minute and at 125° C. for 5 minutes under normal pressure to form an ultraviolet curable pressure-sensitive adhesive layer (1). On the other hand, the pressure-sensitive adhesive solution (1) obtained above was applied onto the release-treated surface of a release liner (trade name “MRF38”, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 112.5 μm. It was applied and dried by heating at 50° C. for 1 minute and at 125° C. for 5 minutes under normal pressure to form an ultraviolet curable pressure-sensitive adhesive layer (2).

Then, the adhesive layer 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 placed together using a hand roller so as not to introduce air bubbles. They were bonded together to form one UV-curable adhesive layer. After that, the release liner was peeled off. Thus, a laminate having a configuration of [PET film/ultraviolet-curing pressure-sensitive adhesive layer] was produced.

(Radiation non-curable adhesive layer)
Butyl acrylate (BA) 189.77 parts by mass, cyclohexyl acrylate (CHA) 38.04 parts by mass, 2-hydroxyethyl acrylate (HEA) 85.93 parts by mass, 2,2'-azo as a polymerization initiator 0.94 parts by mass of bisisobutyronitrile and 379.31 parts by mass of methyl ethyl ketone as a polymerization solvent were placed in a 1 L round bottom separable flask, a separable cover, a separating funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, The mixture was placed in a polymerization experimental apparatus equipped with a vacuum seal, a stirring rod, and a stirring blade, and the mixture was replaced with nitrogen at room temperature for 6 hours while stirring. Thereafter, polymerization was carried out by holding at 65° C. for 4 hours and at 75° C. for 2 hours while stirring under flowing nitrogen to obtain a resin solution.
1.5 parts by mass of an isocyanate compound (trade name: "Coronate L" manufactured by Tosoh Corporation, solid content: 75% by mass) was mixed with the resulting resin solution based on 100 parts by mass of the solid content of the base polymer. Using toluene as a diluting solvent, the solid content was adjusted to 20 to 40% by mass to obtain an adhesive solution (2).

This pressure-sensitive adhesive solution (2) was applied onto the release-treated surface of a release liner (trade name “MRF38”, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 25 μm, and the temperature was maintained at 125° C. under normal pressure. for 2 minutes to form a non-radiation-curable pressure-sensitive adhesive layer.

(PET film/ultraviolet curable adhesive layer/radiation non-curable adhesive layer)
The non-radiation-curable adhesive layer is applied to the surface of the UV-curable adhesive layer of the laminate having the structure of [PET film/UV-curable adhesive layer] using a hand roller so as not to introduce air bubbles. Matched. In this way, a laminate having a structure of [PET film/ultraviolet curable adhesive layer/radiation non-curable adhesive layer/release liner] was produced.

<Sheet for optical semiconductor element encapsulation>
The release liner is peeled off from the laminate having the structure of [TAC film/binder adhesive layer/release liner], and the exposed binder adhesive layer surface is covered with [PET film/ultraviolet curable adhesive layer/radiation non-curable adhesive layer]. /Release liner] was laminated to the PET film surface of the laminate using a hand roller so as not to introduce air bubbles. After that, aging is performed at 50° C. for 48 hours, and Example 1 having a layer structure of [TAC film/binder adhesive layer/PET film/ultraviolet curable adhesive layer/radiation non-curable adhesive layer/release liner]. A sheet for optical semiconductor element encapsulation was produced.

Examples 2-5
In the preparation of the UV-curable adhesive layer, in the same manner as in Example 1, except that the blending amounts of 2-isocyanatoethyl methacrylate (MOI) and dibutyltin dilaurate (IV) were changed as shown in the table. Sheets for encapsulating optical semiconductor elements of Examples 2 to 5 were prepared.

Comparative example 1
The adhesive solution (2) prepared in Example 1 was applied to the treated surface of a PET film (trade name “T912E75 (UE80-)”, manufactured by Mitsubishi Chemical Corporation, thickness 75 μm), and the thickness after drying was 125 μm. and dried under normal pressure by heating at 50° C. for 1 minute and at 125° C. for 5 minutes to form a radiation non-curable pressure-sensitive adhesive layer (1). On the other hand, the pressure-sensitive adhesive solution (2) prepared in Example 1 was applied onto the release-treated surface of a release liner (trade name “MRF38”, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 125 μm. and dried by heating at 50° C. for 1 minute and at 125° C. for 5 minutes under normal pressure to form a radiation non-curable pressure-sensitive adhesive layer (2).

Then, the radiation non-curable adhesive layer (1) formed on the PET film and the radiation non-curable adhesive layer (2) formed on the release liner are adhered to each other using a hand roller so that air bubbles do not enter. to form one radiation non-curable adhesive layer. Thus, a laminate having a configuration of [PET film/non-radiation-curable pressure-sensitive adhesive layer/release liner] was produced.

The release liner was peeled off from the laminate having the structure of [TAC film/binder adhesive layer/release liner] prepared in Example 1, and the exposed binder adhesive layer surface was treated with [PET film/radiation non-curable adhesive layer/ [Release liner] was laminated to the PET film surface of the laminate using a hand roller so as not to introduce air bubbles. After that, it was aged at 50° C. for 48 hours, and had a layer structure of [TAC film/binder adhesive layer/PET film/radiation non-curable adhesive layer/release liner] for optical semiconductor element encapsulation of Comparative Example 1. A sheet was produced.

Comparative example 2
In the preparation of the UV-curable adhesive layer, the adhesive solution of Example 1 ( Adhesive solution (3) was obtained in the same manner as in 1).
Then, the prepared adhesive solution (3) is applied to the treated surface of a PET film (trade name “T912E75 (UE80-)”, manufactured by Mitsubishi Chemical Corporation, thickness 75 μm) so that the thickness after drying becomes 125 μm. and dried under normal pressure by heating at 50° C. for 1 minute and at 125° C. for 5 minutes to form an ultraviolet curable adhesive layer (3). On the other hand, the pressure-sensitive adhesive solution (3) prepared above was applied onto the release-treated surface of a release liner (trade name “MRF38”, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 125 μm, Under normal pressure, it was dried by heating at 50° C. for 1 minute and at 125° C. for 5 minutes to form an ultraviolet curable pressure-sensitive adhesive layer (4).

Then, the adhesive layer surfaces of the UV-curable adhesive layer (3) formed on the PET film and the UV-curable adhesive layer (4) formed on the release liner were put together using a hand roller so as not to introduce air bubbles. They were bonded together to form one UV-curable adhesive layer. Thus, a laminate having a configuration of [PET film/ultraviolet-curing pressure-sensitive adhesive layer/release liner] was produced.

The release liner was peeled off from the laminate having the structure of [TAC film/binder adhesive layer/release liner] prepared in Example 1, and the exposed binder adhesive layer surface was covered with [PET film/ultraviolet curable adhesive layer/release Liner] was laminated to the PET film surface of the laminate using a hand roller so as not to introduce air bubbles. Thereafter, aging was performed at 50° C. for 48 hours, and the sheet for optical semiconductor element encapsulation of Comparative Example 2 having a layer structure of [TAC film/binder adhesive layer/PET film/ultraviolet curable adhesive layer/release liner]. was made.

<Evaluation>
The UV-curable pressure-sensitive adhesive layers and sheets for optical semiconductor element encapsulation obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in the table.

(1) Hardness by nanoindentation method For the optical semiconductor element encapsulation sheets obtained in Examples and Comparative Examples, the surface hardness by nanoindentation method before and after curing of the UV-curable adhesive layer was measured. was measured. Curing of the UV-curable pressure-sensitive adhesive layer was performed by irradiating UV rays from the TAC film side under the following UV irradiation conditions. Then, after freezing the optical semiconductor element encapsulating sheet before and after curing the UV-curable adhesive layer at -40 ° C. to -30 ° C. for 10 to 15 minutes, the thickness using an ultramicrotome under the freezing conditions A cross section of the UV-curable adhesive layer was exposed by cutting in the longitudinal direction. Then, after fixing the optical semiconductor element encapsulation sheet with its cross section exposed on the metal stage attached to the device by hardening Pentel correction liquid (product number “XEZL1-W”), polyimide is applied to the window of the device, etc. Evaluation was performed after affixing a film to block light. Using a nanoindenter (trade name “TriboIndenter”, manufactured by HYSITRON Inc.), nanoindentation was measured on the surface of the UV-curable pressure-sensitive adhesive layer before and after curing under the following nanoindentation measurement conditions. Table 1 shows the hardness obtained.
<Ultraviolet irradiation conditions>
Ultraviolet irradiation device: product name “UM810” manufactured by Nitto Seiki Co., Ltd. Light source: high-pressure mercury lamp Irradiation intensity: 50 mW/cm ² (Measuring device: product name “Ultraviolet illuminance meter UT-101” manufactured by Ushio Inc.)
Irradiation time: 100 seconds Cumulative amount of light: 5000 mJ/cm ²
<Nanoindentation measurement conditions>
Indenter used: Berkovich (triangular pyramid type)
Measurement method: single indentation measurement Measurement temperature: 23°C
Push depth setting: 3.0 μm
Loading speed: 500 nm/s
Unloading speed: 500 nm/s

(2) Dicing evaluation For the optical semiconductor element encapsulation sheets obtained in Examples and Comparative Examples, a release liner was applied to the pattern surface of the substrate (trade name “Lead-free universal substrate ICB93SGPBF” manufactured by Sanhayato Co., Ltd.). A test sample was prepared by laminating the entire surface of the pressure-sensitive adhesive layer exposed by peeling with a hand roller. In addition, the area of the pressure-sensitive adhesive layer of the sheet for optical semiconductor element encapsulation is larger than the area of the substrate to be bonded. The bonding was performed in an environment of 22° C. temperature and 50% humidity, in such a way as not to introduce air bubbles. Thereafter, the above test sample was irradiated with ultraviolet rays from the TAC film side under the following ultraviolet irradiation conditions (1) to cure the ultraviolet-curable pressure-sensitive adhesive layer. The test sample using the sheet for encapsulating optical semiconductor elements of Comparative Example 1, which did not have an ultraviolet-curing adhesive layer, was not irradiated with ultraviolet rays.
<Ultraviolet irradiation conditions (1)>
Ultraviolet irradiation device: product name “UM810” manufactured by Nitto Seiki Co., Ltd. Light source: high-pressure mercury lamp Irradiation intensity: 50 mW/cm ² (Measuring device: product name “Ultraviolet illuminance meter UT-101” manufactured by Ushio Inc.)
Irradiation time: 100 seconds Cumulative amount of light: 5000 mJ/cm ²

After the ultraviolet irradiation, a dicing tape (trade name “NBD-5172K” manufactured by Nitto Denko Corporation) was attached to the substrate surface of the test sample, which was the side to which the optical semiconductor element encapsulation sheet was not attached. A dicing ring for dicing was attached to the adhesive surface of the dicing tape. After application, the patch was allowed to stand for 30 minutes in a light-shielded environment at a temperature of 22°C. After that, under the following dicing conditions, the laminate of the test sample and the dicing tape was diced with a blade at a position 5 mm inward from the side edge of the substrate.
<Dicing conditions>
Dicing machine: Product name “DFD-6450” manufactured by Disco Co., Ltd. Cutting method: Single cut Dicing speed: 30 mm/sec Dicing blade: Product name “P1A861 SDC400N75BR597” manufactured by Disco Co., Ltd. Dicing blade rotation speed: 30,000 rpm
Blade height: 85 μm
Water volume: 1.5 L/min Dicing interval: 10 mm
Distance of one dicing: full length of test sample

The blade used for dicing was subjected to dress dicing by the following method.
A dicing ring and a board (trade name “DRESSER BOARD BGCA0172”, manufactured by Disco Co., Ltd.) were attached to the adhesive layer of a dicing tape (trade name “NBD-7163K”, manufactured by Nitto Denko Corporation), and a processing was performed. A workpiece was produced. Then, the obtained workpiece was diced under the following dress dicing conditions to obtain a blade for the blade dicing.
<Dress dicing conditions>
Dicing device: Product name "DFD-6450", manufactured by Disco Co., Ltd. Cutting method: Single cut Dicing speed: 55 mm / sec Dicing blade: Product name "P1A861 SDC400N75BR597" (new), manufactured by Disco Co., Ltd. Dicing blade rotation speed: 35, 000rpm
Blade height: 500 μm
Water volume: 1.5 L/min Distance of one dicing: Full length of the board Dicing interval: 1 mm increment Number of dicing: 100 times

After blade dicing, 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 from the substrate.
<Ultraviolet irradiation conditions (2)>
Ultraviolet irradiation device: product name “UM810” manufactured by Nitto Seiki Co., Ltd. Light source: high-pressure mercury lamp Irradiation intensity: 50 mW/cm ² (Measuring device: product name “Ultraviolet illuminance meter UT-101” manufactured by Ushio Inc.)
Irradiation time: 10 seconds Accumulated amount of light: 500 mJ/cm ²

After that, the laminate of the test sample and the substrate, which was cut into strips by blade dicing, was peeled off from the dicing tape. Those that could not be confirmed were evaluated as "A".

(3) Arithmetic mean height Sa of cross section
The laminate of the test sample and substrate cut into strips in the dicing evaluation was peeled off from the dicing tape. Then, the arithmetic mean height Sa was measured for the cross section of the exposed cured product of the ultraviolet curable resin layer. For Comparative Example 1, which does not have an ultraviolet curable resin layer, the arithmetic mean height Sa was measured for the section of the non-radiation curable pressure-sensitive adhesive layer. Specifically, a double-sided adhesive tape (trade name “No. 5000NS” manufactured by Nitto Denko Corporation) was attached to the surface of an unground Si mirror wafer. Next, the strip-shaped laminate was attached to the exposed surface of the double-sided adhesive tape (the surface not in contact with the Si mirror wafer) using tweezers. The dicing cut surface and the double-sided adhesive tape were pasted together so that the outermost surface (the surface farthest from the double-sided adhesive tape) was the last diced cut surface. Finally, the diced cut surface was observed and measured using a laser microscope (product name “VK-X150”, manufactured by Keyence Corporation). "Observation application VK-H1XV2 version 2.5.0.0" (manufactured by KEYENCE CORPORATION) was used as PC software. The objective lens used was "20X/0.46 OFN25 WD 3.1" (manufactured by Nikon Corporation). The roughness of the dicing cut surface was measured using the PC software "shape measurement" with the following measurement settings.
<Measurement settings>
Measurement mode: transparent object (outermost surface)
Measurement size: standard (1024 x 768)
Measurement quality: High accuracy Pitch: 0.75 μm

The three-dimensional data obtained by the measurements were then stored. Note that the cross section of the layer to be measured was displayed from the left end to the right end of the screen (the cross section of the layer with a thickness of 250 µm or less was within the screen). After that, "tilt correction" in the "image processing" of the PC software was performed. As a correction method, surface tilt correction (profile) was selected, and tilt correction was performed so that the cut surface was horizontal while the center of the two lines was aligned with the layer center of the observed image obtained. After correcting the tilt, the corrected three-dimensional data was saved. Then, the three-dimensional data was analyzed using PC software for analysis "multi-file analysis application VK-H1XM version 1.1.22.87" (manufactured by KEYENCE CORPORATION). The "surface roughness" of the analysis PC software was selected, the entire layer cross-section shown as an image was selected, and the arithmetic mean height Sa (μm) was measured.

(4) Stringing Evaluation Two laminates of the test sample and substrate cut into strips in the above dicing evaluation were separated from the dicing tape. Next, the cut surfaces of the two laminates exposed by dicing were adhered to each other, and left in this state for 24 hours in an environment at a temperature of 50°C. After that, the two strips adhered to each other were taken out and left for 3 hours in an environment with a temperature of 22° C. and a humidity of 50%. After that, an attempt was made to peel off the adhered cut surfaces by hand, and those that could not be peeled off, or those that could be peeled off but had noticeable stringiness of the adhesive layer were rated as "D" and pulled. "C" indicates that the adhesive layer could be peeled off but a slight stringiness of the adhesive layer was confirmed, and "B" indicates that the adhesive layer required force to be peeled off but could be peeled off without stringiness of the adhesive layer. The adhesive layer was evaluated as "A" when it could be peeled off without requiring a particular force and without stringiness of the adhesive layer.

As shown in Table 1, the sheets for optical semiconductor element encapsulation of the present invention (Examples) had good results in the dicing evaluation, excellent adhesion of the sheet to the optical semiconductor elements and the substrate, and excellent sealing properties of the optical semiconductor elements. It was evaluated as having excellent stopping properties. In addition, the result of the stringing evaluation was good, and the adhesiveness of the side surface of the sealing part was low, and when the adjacent optical semiconductor devices were separated from each other, it was evaluated that the damage of the sheet and the adhesion of the sheets of the adjacent optical semiconductor devices were unlikely to occur. was done.

On the other hand, when it did not have an ultraviolet curable adhesive layer (Comparative Example 1), the result of stringing evaluation was inferior. In the case of not having a non-radiation-curable adhesive layer (Comparative Example 2), the result of the dicing evaluation was inferior, and the optical semiconductor element encapsulation was evaluated as being inferior.

1 sheet for optical semiconductor element encapsulation 1' cured product of sheet for optical semiconductor element encapsulation 2 base material part 21 optical film 22 adhesive layer 23 plastic film 3 encapsulation part 31 radiation curable resin layer 31' cured encapsulation layer 32 Radiation non-curable adhesive layer 4 Release liner 5 Substrate 6 Optical semiconductor device 10, 20 Optical semiconductor device

Claims (11)

A sheet for sealing one or more optical semiconductor elements arranged on a substrate,
A base member, and a sealing portion provided on one surface of the base member for encapsulating the optical semiconductor element,
The sealing portion has a radiation non-curable adhesive layer and a radiation curable resin layer,
The sheet for optical semiconductor element encapsulation, wherein the radiation-curable resin layer contains a polymer having a radiation-polymerizable functional group. 2. The sheet for optical semiconductor element encapsulation according to claim 1, wherein said radiation curable resin layer is thicker than said radiation non-curable adhesive layer. The sheet for optical semiconductor element encapsulation according to claim 1 or 2, wherein the encapsulating portion includes a layer containing a coloring agent. 4. The sheet for optical semiconductor element encapsulation according to any one of claims 1 to 3, comprising a layer having antiglare properties and/or antireflection properties. The sheet for encapsulating optical semiconductor elements according to any one of claims 1 to 4, comprising a layer containing a polyester resin and/or a polyimide resin as a main component. The optical semiconductor element encapsulation according to any one of claims 1 to 5, wherein the cured cross section of the radiation-curable resin layer has a hardness of 1.4 MPa or more at a temperature of 23°C by a nanoindentation method. sheet. The radiation-curable resin of the sheet for encapsulating an optical semiconductor element according to any one of claims 1 to 6, which seals a substrate, an optical semiconductor element arranged on the substrate, and the optical semiconductor element. and a cured product obtained by curing the layer. 8. The optical semiconductor device according to claim 7, which is a backlight for a liquid crystal screen. An image display device comprising the backlight according to claim 8 and a display panel. 8. The optical semiconductor device according to claim 7, which is a self-luminous display device. An image display device comprising the self-luminous display device according to claim 10 .

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