JP7447035B2 - Sheet for encapsulating optical semiconductor devices - Google Patents

Description

The present invention relates to a sheet for encapsulating optical semiconductor devices. More specifically, the present invention 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. A method of collectively sealing the plurality of LEDs using the sealing resin is to pour the liquid resin into an area where the plurality of LEDs are arranged, bury the plurality of LEDs, and then irradiate the LEDs with heat or ultraviolet rays. A method of curing liquid resin is known (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2017-66390

However, the method of sealing optical semiconductor elements such as LEDs using liquid resin has problems such as poor handling, such as dripping when applying the liquid resin and adhesion of the liquid resin to unintended areas. there were.

On the other hand, instead of using liquid resin, it is possible to form an encapsulation sheet with a sealing layer for encapsulating the optical semiconductor element, which is easy and allows the optical semiconductor element to be manufactured in a simple process and in a short time. It is conceivable to seal the element. Here, it is important that the above-mentioned sealing sheet has excellent sealing properties for the optical semiconductor element and excellent adhesion to the optical semiconductor element and the substrate provided with the optical semiconductor element in order to sufficiently seal the optical semiconductor element. It is.

Incidentally, with the trend towards higher image quality such as 4K and 8K, demand for larger screen image display devices is increasing. In addition, large-screen image display devices are increasingly being used for advertising displays outdoors, in public facilities, and for signage such as bulletin boards. However, manufacturing a large-screen image display device causes problems such as a decrease in yield and an increase in manufacturing cost. In order to manufacture large-screen image display devices at lower cost, tiling displays in which a plurality of optical semiconductor devices such as image display devices are arranged in a tile shape are being considered. During tiling, where multiple optical semiconductor devices are arranged in a tiled pattern, position correction is performed when adjacent optical semiconductor devices are misaligned or need to be rearranged. .

Here, when tiling optical semiconductor devices in which optical semiconductor elements are sealed with a sealing sheet, it is necessary to temporarily separate adjacent optical semiconductor devices in order to correct the position during tiling. However, when separated, the sealing sheet in one optical semiconductor device and the adjacent sealing sheet in the other optical semiconductor device come into close contact with each other, causing damage to the sealing sheet in one optical semiconductor device. There may be a problem that a part of one sealing sheet is transferred and attached to the other optical semiconductor device. Sealing sheets that have excellent adhesion to optical semiconductor elements and substrates are particularly prone to such defects.

The present invention was devised under these circumstances, and its purpose is to provide excellent sealing properties for optical semiconductor elements while preventing sheet damage and damage when separating adjacent optical semiconductor devices. It is an object of the present invention to provide a sheet for encapsulating an optical semiconductor element in which adhesion of sheets of adjacent optical semiconductor devices is less likely to occur.

As a result of intensive studies to achieve the above object, the inventors of the present invention have provided a sealing portion having a radiation-non-curable adhesive layer and a radiation-curable resin layer, and the radiation-curable resin layer has a radiation-polymerizable functional group. According to a sheet for encapsulating optical semiconductor devices containing a polymer having It was found that adhesion was less likely to occur. The present invention was completed based on these findings.

That is, the present invention is a sheet for sealing one or more optical semiconductor elements arranged on a substrate,
comprising a base material part and a sealing part provided on one surface of the base material part for sealing the optical semiconductor element,
The sealing part has a radiation-non-curable adhesive layer and a radiation-curable resin layer,
The radiation-curable resin layer provides a sheet for encapsulating an optical semiconductor device, which contains a polymer having a radiation-polymerizable functional group.

As described above, the optical semiconductor element sealing sheet includes a sealing portion in which a radiation-non-curable adhesive layer and a radiation-curable resin layer are laminated. The sealing portion is a region of the optical semiconductor element sealing sheet that seals the optical semiconductor element. 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 is difficult to migrate from the radiation-curable resin layer to the radiation-non-curable adhesive layer laminated thereon. For this reason, when radiation is applied after sealing the optical semiconductor element, the radiation-curable resin layer is sufficiently cured and the adhesion to the side surface of the sealing sheet is reduced, and the non-radiation-curable adhesive layer is Since unintended curing is suppressed, the adhesive strength is less likely to decrease, the original adhesiveness can be exhibited, and the sealing properties of optical semiconductor devices are excellent. As a result, while the optical semiconductor element has excellent sealing performance, the adhesion between the sides of the sealing parts of adjacent optical semiconductor devices in a tiling state is low, and when separating adjacent optical semiconductor devices, the optical semiconductor device Sheet defects on the side surfaces and adhesion of adjacent optical semiconductor device sheets are less likely to occur. Moreover, the base material part serves as a support for the sealing part, and by providing the base material part, the sheet for encapsulating an optical semiconductor element has excellent handling properties. Furthermore, when dicing the optical semiconductor device after sealing the optical semiconductor element with the optical semiconductor element sealing sheet, stickiness of the dicing portion can be suppressed, and an optical semiconductor device with good appearance can be manufactured. .

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 adjacent optical semiconductor devices is lower than the high adhesion between radiation-curable adhesive layers in adjacent optical semiconductor devices in the tiling state. Since adhesion is dominant, the adhesion between the sealing parts is even lower, and when adjacent optical semiconductor devices are separated from each other, it is even less likely that sheets will be damaged or sheets of adjacent optical semiconductor devices will adhere. Further, when an optical semiconductor device is fabricated by sealing an optical semiconductor element with an optical semiconductor element sealing sheet and then diced, stickiness of the dicing portion can be further suppressed, and an optical semiconductor device with a good appearance can be fabricated. Can be done.

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

The sheet for encapsulating an optical semiconductor element preferably includes a layer having anti-glare properties and/or anti-reflection properties. By having such a configuration, when the optical semiconductor device is tiled and applied to a display, it is possible to suppress the gloss of the display and the reflection of light, and improve the appearance of the display.

The optical semiconductor element sealing sheet preferably includes a layer containing a polyester resin and/or a polyimide resin as a main component. By having such a configuration, the sheet for encapsulating an optical semiconductor element has excellent heat resistance, can suppress thermal expansion of the sheet for encapsulating an optical semiconductor element in a high-temperature environment, and improves dimensional stability. Furthermore, since rigidity can be imparted to the sheet, handling and holding properties are improved.

The hardness of the cured cross section of the radiation-curable resin layer measured by nanoindentation at a temperature of 23° C. is preferably 1.4 MPa or more. By having such a structure, the radiation-curable resin layer has appropriate hardness after curing, and when separating adjacent optical semiconductor devices in a tiling state, there is no damage to the sheet or damage to adjacent optical semiconductor devices. Sticking of the sheets of the device is even less likely to occur.

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

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

Further, the present invention provides an image display device including the above-described backlight and a display panel.

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

According to the optical semiconductor element sealing sheet of the present invention, although the optical semiconductor element sealing properties are excellent, when adjacent optical semiconductor devices are separated from each other, the sheet may be damaged or the sheets of adjacent optical semiconductor devices may adhere. Hateful. Therefore, after tiling of optical semiconductor devices, if a positional shift occurs between adjacent optical semiconductor devices or if rearrangement is required, the position can be easily corrected without any problems. Loss of the device can be reduced, and a display with good appearance can be manufactured economically.

FIG. 1 is a cross-sectional view of a sheet for encapsulating an optical semiconductor device according to an embodiment of the present invention. FIG. 1 is a cross-sectional view of an optical semiconductor device using an optical semiconductor element sealing sheet according to an embodiment of the present invention. 3 is an external view showing an embodiment of an optical semiconductor device manufactured by tiling the optical semiconductor device shown in FIG. 2. FIG. FIG. 2 is a cross-sectional view showing a sealing process in an embodiment of a method for manufacturing an optical semiconductor device. 5 is a cross-sectional view showing a laminate obtained after the sealing step shown in FIG. 4. FIG. FIG. 6 is a cross-sectional view showing a laminate obtained by subjecting the laminate shown in FIG. 5 to a radiation irradiation step. 7 is a cross-sectional view showing dicing positions in the dicing process of the laminate shown in FIG. 6. FIG.

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

The optical semiconductor device sealing sheet of the present invention may include a release liner in addition to the base portion and the sealing portion. In this case, the release liner is bonded to the surface of the sealing portion opposite to the base material 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.

Moreover, the sheet for optical semiconductor element sealing of the present invention may be equipped with a surface protection film on the surface of the base material portion (the surface on the opposite side to the sealing portion). When using, for example, an optical film described below as the base material portion, the optical film can be protected until use. Note that the surface protection film does not necessarily have to be provided.

Hereinafter, one embodiment of the sheet for encapsulating an optical semiconductor element of the present invention will be described. FIG. 1 is a cross-sectional view showing one embodiment of the optical semiconductor device sealing sheet of the present invention. As shown in FIG. 1, the optical semiconductor element sealing sheet 1 can be used to seal one or more optical semiconductor elements arranged on a substrate, and includes a base material part 2, It includes a sealing part 3 and a release liner 4. The sealing part 3 is provided on one surface of the base material part 2. The release liner 4 is attached to the surface of the sealing part 3 (the surface on the opposite side to the side having the base material part 2). In other words, the optical semiconductor element sealing sheet 1 includes the base portion 2, the sealing portion 3, and the release liner 4 in this order. The base material part 2 is a multilayer structure 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 part 3 is composed of a radiation-curable resin layer 31 and a radiation-non-curable adhesive layer 32.

The sheet for encapsulating an optical semiconductor element preferably includes a layer having anti-glare properties and/or anti-reflection properties. By having such a configuration, when the optical semiconductor device is tiled and applied to a display, it is possible to suppress the gloss of the display and the reflection of light, and improve the appearance of the display. Examples of the layer having anti-glare properties include an anti-glare treated layer. Examples of the layer having antireflection properties include an antireflection treated layer. The anti-glare treatment and the anti-reflection treatment can be carried out using known or commonly used methods. The layer having anti-glare properties and the layer having anti-reflection properties may be the same layer or may be different layers. The layer having anti-glare properties and/or anti-reflection properties may have only one layer, or may have two or more layers.

The layer having anti-glare properties and/or anti-reflection properties may be a layer included in the base part, a layer included in the sealing part, or another layer not included in the base part and the sealing part. Although it may be any layer, it is preferably a layer included in the base material portion and/or the sealing portion, and more preferably a layer contained in the base material portion.

The optical semiconductor element sealing sheet preferably includes a layer containing a polyester resin and/or a polyimide resin as a main component (component having the highest mass ratio among the constituent resins). By having such a configuration, the sheet for encapsulating an optical semiconductor element has excellent heat resistance, can suppress thermal expansion of the sheet for encapsulating an optical semiconductor element in a high-temperature environment, and improves dimensional stability. Furthermore, since rigidity can be imparted to the sheet, handling and holding properties are improved. The layer containing the above-mentioned polyester resin and/or polyimide resin as a main component may have only one layer, or may have two or more layers.

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

<Sealing part>
The sealing portion has a resin layer having a property of being cured by radiation irradiation (radiation curable resin layer) and an adhesive layer not having a property of being cured by radiation irradiation (radiation non-curable adhesive layer).

(Radiation curable resin layer)
The radiation-curable resin layer includes 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 is difficult to migrate from the radiation-curable resin layer to the radiation-non-curable adhesive layer laminated thereon. For this reason, when radiation is applied after sealing the optical semiconductor element, the radiation-curable resin layer is sufficiently cured and the adhesion to the side surface of the sealing sheet is reduced, and the non-radiation-curable adhesive layer is Since unintended curing is suppressed, the adhesive strength is less likely to decrease, the original adhesiveness can be exhibited, and the sealing properties of optical semiconductor devices are excellent. As a result, while the optical semiconductor element has excellent sealing performance, the adhesion between the side surfaces of the sealing parts of adjacent optical semiconductor devices in a tiling state is low, and when separating adjacent optical semiconductor devices, the optical semiconductor device Sheet defects on the side surfaces and adhesion of adjacent optical semiconductor device sheets are less likely to occur.

On the other hand, when using a conventional radiation-curable resin layer that contains a polymer that does not have radiation-polymerizability as a base polymer and uses a monomer or oligomer that has radiation-polymerizability as a curable component, Monomers and oligomers easily migrate to the laminated radiation-curable adhesive layer. In this case, even if such a radiation-curable resin layer with a reduced amount of curable components is cured, the curing will be insufficient, the adhesion of the side surface of the sealing sheet will not deteriorate easily, and the stickiness of the side surface will be sufficiently reduced. I can't. In addition, the non-radiation-curable adhesive layer into which the curable component has penetrated will undergo unintended curing during radiation irradiation, resulting in a decrease in adhesive strength and the inability to exhibit the original adhesion. This results in poor sealing performance.

Furthermore, when dicing the optical semiconductor device after sealing the optical semiconductor element with the optical semiconductor element sealing sheet and manufacturing the optical semiconductor device, stickiness of the dicing portion can be suppressed, and an optical semiconductor device with good appearance can be manufactured. . Furthermore, when a conventional radiation-curable resin layer is used, the radiation-polymerizable monomer or oligomer has low compatibility within the radiation-curable resin layer, resulting in poor transparency after curing. On the other hand, since the sheet for encapsulating an optical semiconductor element of the present invention includes the radiation-curable resin layer, it 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 structure, when sealing the optical semiconductor element, the optical semiconductor element can be easily embedded, and the base material part, the radiation non-curable adhesive layer, and the optical semiconductor element can be easily embedded before being cured by radiation. It has excellent adhesion to devices and better sealing properties for optical semiconductor devices. Examples of the radiation include active energy rays such as electron beams, ultraviolet rays, α rays, β rays, γ rays, and X rays. Among these, ultraviolet light is preferred.

The radiation-curable resin layer preferably contains the polymer having the radiation-polymerizable functional group as a base polymer (that is, the polymer with the highest content). The content ratio of the polymer having the radiation-polymerizable functional group in the radiation-curable resin layer is 50% by mass or more (for example, 50 to 100% by mass) based on 100% by mass of the total amount of the radiation-curable resin layer. It is preferably 80% by mass or more (for example, 80 to 100% by mass), and even more preferably 90% by mass or more (for example, 90 to 100% by mass). When the content ratio is 50% by mass or more, the radiation-curable resin layer has better curability, and the tackiness of the side surface is further reduced by radiation irradiation. Moreover, the transparency of the sheet for encapsulating an optical semiconductor element is even more excellent.

Examples of the radiation polymerizable functional group include radiation radical polymerizable groups such as groups containing a carbon-carbon unsaturated bond such as ethylenically unsaturated groups, radiation cationic polymerizable groups, and the like. Examples of the group containing a carbon-carbon unsaturated bond include a vinyl group, a propenyl group, an isopropenyl group, an acryloyl group, a methacryloyl group, and the like. Examples of the radiation cationically polymerizable group include an epoxy group, an oxetanyl group, an oxolanyl group, and the like. Among these, groups containing a carbon-carbon unsaturated bond are preferred, and acryloyl and methacryloyl groups are more preferred. The number of the radiation polymerizable functional groups may be one type or two or more types. The radiation-polymerizable functional group may be located on a side chain of the polymer, in the main chain of the polymer, or at the end of the main chain of the polymer.

The radiation-polymerizable functional group-containing polymer has, for example, a functional group that can cause a reaction between a polymer having a reactive functional group (first functional group) and the first functional group to form a bond. (second functional group) and the compound having the radiation-polymerizable functional group can be produced by a method of reacting and bonding while maintaining the radiation-polymerizability of the radiation-polymerizable functional group. Therefore, the polymer having the radiation polymerizable functional group has a structural part derived from the polymer having the first functional group, and a structural part derived from the compound having the second functional group and the radiation polymerizable functional group. It is preferable to 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 carboxyl group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, Examples include isocyanate groups and hydroxy groups. 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 tracking the reaction. The above combination may be 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 polymer, urethane acrylate resin, epoxy resin, epoxy acrylate resin, oxetane resin, and silicone resin. , silicone acrylic resin, polyester resin, etc. Among these, acrylic polymers are preferred. The above polymers may be used alone or in combination of two or more.

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

It is preferable that the acrylic polymer is a polymer containing the largest amount of structural units derived from (meth)acrylic acid ester in mass proportion. In addition, in this specification, "(meth)acrylic" represents "acrylic" and/or "methacrylic" (either or both of "acrylic" and "methacrylic"), and the others are the same. .

Examples of the above (meth)acrylic esters include hydrocarbon group-containing (meth)acrylic esters that may have an alkoxy group. As the hydrocarbon group-containing (meth)acrylic ester in the hydrocarbon group-containing (meth)acrylic ester which may have an alkoxy group, the hydrocarbon group-containing (meth)acrylic ester may have a linear or branched aliphatic hydrocarbon group ( (meth)acrylic acid esters having an alicyclic hydrocarbon group such as meth)acrylic acid alkyl esters, (meth)acrylic acid cycloalkyl esters, and (meth)acrylic acid esters having aromatic hydrocarbon groups such as (meth)acrylic acid aryl esters. ) acrylic esters, etc. 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 esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, and (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 Examples include hexadecyl, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

Among the above (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, even more preferably 2 to 8) carbon atoms are used. Preferred are (meth)acrylic acid alkyl esters having group hydrocarbon groups. When the number of carbon atoms is within the above range, it is easy to adjust the glass transition temperature of the acrylic polymer, and the adhesion of the radiation-curable resin layer can be made more appropriate.

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

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

Examples of the hydrocarbon group-containing (meth)acrylic 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 ester are substituted with an alkoxy group, Examples include 2-methoxymethyl ester, 2-methoxyethyl ester, and 2-methoxybutyl ester of (meth)acrylic acid.

The hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group includes, among others, (meth)acrylic acid alkyl esters having a linear or branched aliphatic hydrocarbon group. is preferable, and it is more preferable that a (meth)acrylic acid ester having an alicyclic hydrocarbon group is further included. In this case, the adhesion of the radiation-curable resin layer is well balanced, and the sealing properties of the optical semiconductor element are more excellent.

In order to appropriately exhibit basic properties such as tackiness and adhesion to optical semiconductor elements by the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group in the radiation-curable resin layer, The proportion of the hydrocarbon group-containing (meth)acrylic acid ester that 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. Further, the above ratio is preferably 95 mol% or less, more preferably 80 mol% or less, from the viewpoint of copolymerizing other monomer components and obtaining the effects of the other monomer components.

The proportion of the (meth)acrylic acid alkyl ester having a linear or branched aliphatic hydrocarbon group in all the monomer components constituting the acrylic polymer having the first functional group is the total amount of all the monomer components described above. (100 mol%), preferably 30 mol% or more, more preferably 40 mol% or more. Further, 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 the monomer components constituting the acrylic polymer having the first functional group is based on the total amount (100 mol%) of all the monomer components described above. , is preferably 1 mol% or more, more preferably 5 mol% or more. Moreover, the said ratio is preferably 30 mol% or less, more preferably 20 mol% or less.

The acrylic polymer is a hydrocarbon group-containing (meth)acrylic acid which may have an alkoxy group, for the purpose of introducing the first functional group and for the purpose of modifying cohesive force, heat resistance, etc. It may also contain structural units derived from other monomer components copolymerizable with the ester. Examples of the other monomer components include polar groups such as carboxy group-containing monomers, acid anhydride monomers, hydroxy group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and nitrogen atom-containing monomers. Examples include containing monomers. Each of the above other monomer components may be used alone or in combination of two or more.

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, Examples include 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

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

Examples of the sulfonic acid group-containing monomers include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acrylamidopropanesulfonic acid. ) Acryloyloxynaphthalene sulfonic 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 the polar group-containing monomer constituting the acrylic polymer includes a hydroxy group-containing monomer. By using a hydroxy group-containing monomer, it is easy to introduce the first functional group. In addition, the acrylic polymer and 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.

The hydroxy group-containing monomer is preferably 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate, more preferably 2-hydroxyethyl (meth)acrylate.

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

The acrylic polymer may contain a structural unit derived from a polyfunctional (meth)acrylate copolymerizable with a 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. The above polyfunctional (meth)acrylates may be used alone or in combination of two or more.

In order to appropriately exhibit basic properties such as tackiness and adhesion to optical semiconductor elements by the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group in the radiation-curable resin layer, The proportion of the polyfunctional (meth)acrylate in all 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. .

Among the combinations of the first functional group and the second functional group, it is technically difficult to produce a polymer having a highly reactive isocyanate group, while 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 preferred.

Examples of the compound having the radioactive polymerizable functional group and isocyanate group include methacryloyl isocyanate, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate (MOI), m-isopropenyl-α,α-dimethylbenzyl isocyanate, and the like. It will be done. The above compounds may be used alone or in combination of two or more.

The content of the structural portion derived from the second functional group and the compound having a radiation-polymerizable functional group in the acrylic polymer having a radiation-polymerizable functional group promotes the curing of the radiation-curable resin layer. From the viewpoint that it can be used, it is preferably 0.5 mol or more, more preferably 1 mol or more, and even more preferably 3 mol, based on 100 mol of the total amount of structural parts derived from the acrylic polymer having the first functional group. The amount is more preferably 10 moles 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-curable functional group [second functional group/first functional group] is determined by the radiation-curable resin. From the viewpoint of being able to further progress the curing of the layer, it is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.2 or more, and particularly preferably 0.4 or more. Further, the molar ratio is preferably less than 1.0, more preferably 0.9 or less, from the viewpoint of further reducing the amount of low molecular weight substances in the radiation-curable resin layer.

The above-mentioned acrylic polymer having a radiation polymerizable functional group can be obtained, 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. , a compound having the second functional group and a radiation-polymerizable functional group can be produced by a method of subjecting an acrylic polymer to a condensation reaction or an addition reaction while maintaining the radiation-polymerizability of the radiation-polymerizable functional group. .

The acrylic polymer having the first functional group can be obtained by polymerizing the various monomer components described above. This polymerization method is not particularly limited, and includes, for example, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a polymerization method using active energy ray irradiation (active energy ray polymerization method), and the like. Further, the obtained acrylic polymer may be a random copolymer, a block copolymer, a graft copolymer, or the like.

Various common solvents may be used in polymerizing 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 and methylcyclohexane. alicyclic hydrocarbons; organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. The above solvents may be used alone or in combination of two or more.

The polymerization initiator, chain transfer agent, emulsifier, etc. used in the 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 the amounts of the polymerization initiator and chain transfer agent used and the reaction conditions, and the amounts used are adjusted as appropriate depending on the types of these.

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

The thermal polymerization initiator is not particularly limited, but includes, for example, an azo polymerization initiator, a peroxide polymerization initiator, a redox polymerization initiator, and the like. The amount of the thermal polymerization initiator used is preferably 1 part by mass or less, more preferably 0 parts by mass or less, based on 100 parts by mass of all monomer components constituting the first acrylic polymer having a functional group. The amount is .005 to 1 part by weight, more preferably 0.02 to 0.5 part by weight.

Examples of the photopolymerization initiators include benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, and photoactive oxime photopolymerization initiators. Initiator, benzoin-based photoinitiator, benzyl-based photoinitiator, benzophenone-based photoinitiator, ketal-based photoinitiator, thioxanthone-based photoinitiator, acylphosphine oxide-based photoinitiator, titanocene-based photoinitiator Examples include photopolymerization initiators. Among these, acetophenone photopolymerization initiators are preferred.

Examples of the acetophenone photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 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-propan-1 -one, methoxyacetophenone, etc.

The amount of the photopolymerization initiator to be used is preferably 0.005 to 1 part by mass, and more preferably The amount is preferably 0.01 to 0.7 parts by weight, more preferably 0.18 to 0.5 parts by weight. When the above usage amount is 0.005 parts by mass or more (particularly 0.18 parts by mass or more), it is easy to control the molecular weight of the acrylic polymer to a small value, and the residual stress of the radiation-curable resin layer becomes high, resulting in poor step absorbability. It tends 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, by stirring in a solvent in the presence of a catalyst. Examples of the above-mentioned solvent include those mentioned above. The above catalyst is appropriately selected depending on 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 above-mentioned acrylic polymer having a radiation polymerizable functional group may have a structure derived from a crosslinking agent. For example, the acrylic polymer can be crosslinked to further reduce the amount of low molecular weight substances in the radiation-curable resin layer. Moreover, the weight average molecular weight of the acrylic polymer can be increased. Note that the crosslinking agent crosslinks 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 something. The above crosslinking agents may be used alone or in combination of two or more.

Examples of the crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, and metal salt crosslinking agents. Examples include crosslinking agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, amine crosslinking agents, silicone crosslinking agents, and silane crosslinking agents. Among the above-mentioned crosslinking agents, from the viewpoint of excellent adhesion to optical semiconductor devices and the viewpoint of fewer impurity ions, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred, and isocyanate-based crosslinking agents are more preferred.

Examples of the isocyanate crosslinking agent (polyfunctional isocyanate compound) include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; 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 crosslinking agent include trimethylolpropane/tolylene diisocyanate adduct, trimethylolpropane/hexamethylene diisocyanate adduct, and trimethylolpropane/xylylene diisocyanate adduct.

The content of the structural parts derived from the crosslinking agent is not particularly limited, but is 5 parts by mass based on 100 parts by mass of the acrylic polymer having the radiation polymerizable functional group, excluding the structural parts derived from the crosslinking agent. The content is preferably 0.001 to 5 parts by mass, and even more preferably 0.01 to 3 parts by mass.

The radiation-curable resin layer may contain components other than the polymer having the radiation-polymerizable functional group, as long as the effects of the present invention are not impaired. Other ingredients mentioned above include crosslinking 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, ultraviolet absorbers, polymerization inhibitors, granules , foil-like materials, etc. The above-mentioned other components may be used alone or in combination of two or more.

(Radiation non-curable adhesive layer)
As the adhesive forming the radiation-non-curable adhesive layer, a known or commonly used 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-curable compound that migrates and enters from other laminated layers. Examples of the above-mentioned adhesives include acrylic adhesives, rubber adhesives (natural rubber-based, synthetic rubber-based, mixtures thereof, etc.), silicone-based adhesives, polyester-based adhesives, urethane-based adhesives, and polyether. Examples include adhesives such as adhesives based on polyamide, polyamide adhesives, and fluorine adhesives. Among these, acrylic pressure-sensitive adhesives are preferred 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 adhesive layer is preferably an acrylic adhesive layer made of an acrylic adhesive. The above adhesives may be used alone or in combination of two or more.

The acrylic adhesive layer contains an acrylic polymer as a base polymer. The above-mentioned acrylic polymer is a polymer containing an acrylic monomer as a monomer component constituting the polymer. That is, the acrylic polymer includes a structural unit derived from an acrylic monomer. In addition, only one type of acrylic polymer may be used, or two or more types may be used.

The content of the acrylic polymer in the acrylic adhesive layer is not particularly limited, but is preferably 50% by mass or more (for example, 50 to 100% by mass) based on 100% by mass of the total amount of the adhesive layer. , more preferably 80% by mass or more (for example, 80 to 100% by mass), still more preferably 90% by mass or more (for example, 90 to 100% by mass). When the above-mentioned content ratio is 50% by mass or more, the transparency of the optical semiconductor element sealing sheet is more excellent.

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

Examples of the above (meth)acrylic esters include hydrocarbon group-containing (meth)acrylic esters that may have an alkoxy group. The hydrocarbon group-containing (meth)acrylic ester in the hydrocarbon group-containing (meth)acrylic ester which may have an alkoxy group has the above-mentioned linear or branched aliphatic hydrocarbon group. Examples include (meth)acrylic acid alkyl esters, (meth)acrylic esters having the above-mentioned alicyclic hydrocarbon groups, and (meth)acrylic esters having the above-mentioned aromatic hydrocarbon groups. 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 above (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, even more preferably 2 to 8) carbon atoms are used. (meth)acrylic acid alkyl esters having group hydrocarbon groups are 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 adhesive layer can be made more appropriate.

Among the above-mentioned (meth)acrylic esters having an alicyclic hydrocarbon group, (meth)acrylic esters having a monocyclic aliphatic hydrocarbon ring are preferred, and cyclohexyl (meth)acrylate is more preferred. .

The hydrocarbon group-containing (meth)acrylic acid ester that may have an alkoxy group includes, among others, (meth)acrylic acid alkyl esters having a linear or branched aliphatic hydrocarbon group. is preferable, and it is more preferable that a (meth)acrylic acid ester having an alicyclic hydrocarbon group is further included. In this case, the adhesiveness of the non-radiation curable adhesive layer is well balanced and the sealing properties of the optical semiconductor element are more excellent.

In order to appropriately exhibit basic properties such as tackiness and adhesion to optical semiconductor devices by the hydrocarbon group-containing (meth)acrylic acid ester which may have an alkoxy group in the radiation-non-curable adhesive layer. The ratio of the hydrocarbon group-containing (meth)acrylic 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. The content is preferably 40 mol% or more, more preferably 50 mol% or more. Further, the above ratio is preferably 95 mol% or less, more preferably 80 mol% or less, from the viewpoint of copolymerizing other monomer components and obtaining the effects of the other monomer components.

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

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

The acrylic polymer may contain structural units derived from the other monomer components, such as the polar group-containing monomer, for the purpose of modifying cohesive force, heat resistance, and the like. Each of the above other monomer components may be used alone or in combination of two or more.

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

The hydroxy group-containing monomer is preferably 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate, more preferably 2-hydroxyethyl (meth)acrylate.

In order to appropriately exhibit basic properties such as tackiness and adhesion to optical semiconductor devices by the hydrocarbon group-containing (meth)acrylic acid ester which 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, from the viewpoint of improving the water resistance of the radiation-non-curable adhesive layer, it is preferable that the proportion of the hydroxy group-containing monomer is within the above range.

The acrylic polymer may contain a structural unit derived from a polyfunctional monomer copolymerizable with a monomer component constituting the acrylic polymer in order to form a crosslinked structure in the polymer skeleton. In addition to the polyfunctional (meth)acrylates mentioned above, examples of the polyfunctional monomers include epoxy (meth)acrylates (e.g., polyglycidyl (meth)acrylate), polyester (meth)acrylates, urethane (meth)acrylates, etc. Examples include monomers having a (meth)acryloyl group and other reactive functional groups. The above polyfunctional monomers may be used alone or in combination of two or more.

In order to appropriately exhibit basic properties such as tackiness and adhesion to optical semiconductor devices by the hydrocarbon group-containing (meth)acrylic acid ester which 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 crosslinking agent. For example, the acrylic polymer can be crosslinked to further reduce the amount of low molecular weight substances in the radiation-curable resin layer. Moreover, the weight average molecular weight of the acrylic polymer can be increased. The above crosslinking agents may be used alone or in combination of two or more.

The above-mentioned acrylic polymer can be produced by the same method as the above-mentioned first functional group-containing acrylic polymer.

The weight average molecular weight of the acrylic polymer is not particularly limited, but is preferably from 100,000 to 3,000,000, more preferably from 200,000 to 2,500,000. When the weight average molecular weight is within the above range, the adhesion of the radiation-non-curable adhesive layer is well balanced and the sealing properties of the optical semiconductor device are more excellent. The above weight average molecular weight is a value measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

The radiation non-curable adhesive layer may contain other components other than the base polymer as long as the effects of the present invention are not impaired. Examples of the above-mentioned other components include those exemplified and explained as other components that may be included in the above-mentioned radiation-curable resin layer. The above-mentioned other components may be used alone or in combination of two or more.

(Sealing part)
In the sealing portion, the radiation-non-curable adhesive layer and the radiation-curable resin layer are laminated. The radiation-non-curable adhesive layer and the radiation-curable resin layer may be directly laminated without any other layer interposed therebetween, or may be laminated with another layer interposed therebetween. Even if the sealing part has a structure in which the radiation-non-curable adhesive layer and the radiation-curable resin layer are directly laminated, the radiation-polymerizable functional group in the radiation-curable resin layer Since the polymer is difficult to migrate to the radiation-curable adhesive layer, the sheet for encapsulating optical semiconductor elements of the present invention has excellent sealing properties for optical semiconductor elements, and stickiness on the side surfaces is suppressed after curing.

The radiation non-curable adhesive layer and the radiation curable resin layer may each be a single layer, or may be multiple layers that are the same or have different compositions, thicknesses, and the like. When the sealing part has a plurality of at least one of the radiation non-curable adhesive layer and the radiation curable resin layer, the plurality of layers may be laminated consecutively, and It may be laminated.

The sealing layer preferably has the radiation-non-curable adhesive layer on the surface of the sealing portion that faces the optical semiconductor element when sealing the optical semiconductor element. Specifically, the radiation-non-curable adhesive layer is applied to the surface of the sheet for encapsulating an optical semiconductor element that becomes the optical semiconductor element side when sealing the optical semiconductor element (if 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 seals the optical semiconductor element, the radiation non-curable adhesive layer is attached to the optical semiconductor element and the substrate. This results in direct contact, resulting in excellent sealing properties of the optical semiconductor element.

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 adjacent optical semiconductor devices is lower than the high adhesion between radiation-curable adhesive layers in adjacent optical semiconductor devices in the tiling state. Since adhesion is dominant, the adhesion between the sealing parts is even lower, and when adjacent optical semiconductor devices are separated from each other, it is even less likely that sheets will be damaged or sheets of adjacent optical semiconductor devices will adhere. Further, when an optical semiconductor device is fabricated by sealing an optical semiconductor element with an optical semiconductor element sealing sheet and then diced, stickiness of the dicing portion can be further suppressed, and an optical semiconductor device with a good appearance can be fabricated. Can be done. In addition, when it has a plurality of the radiation-curable resin layers and the radiation-non-curable adhesive layers, the thickness is the total thickness of the multiple layers (total thickness).

The thickness (total thickness) of the radiation-curable resin layer is preferably the thickest among all the layers constituting the optical semiconductor element sealing sheet. In particular, it is preferable that the sheet for encapsulating an optical semiconductor element includes a radiation-curable resin layer having the largest thickness among all the layers constituting the sheet for encapsulating an optical semiconductor element. Note that a layer formed by directly laminating a plurality of layers having the same composition can be considered as one layer. Moreover, when there are two or more thickest layers, any layer corresponds to the thickest layer.

For example, in the optical semiconductor element sealing sheet 1 shown in FIG. 1, the sealing portion 3 is composed of a radiation-curable resin layer 31 and a radiation-non-curable adhesive layer 32. The radiation-curable resin layer 31 is located within the sealing portion 3 on the base material portion 2 side. The radiation non-curable adhesive layer 32 is located on the optical semiconductor element side surface in the sealing part 3, and is located on the opposite side of the optical semiconductor element sealing sheet 1 from the base material part 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 sealing portion 3 and the optical semiconductor element sealing sheet 1.

The thickness (total thickness) of the radiation-curable resin layer is preferably 20 to 800 μm, more preferably 30 to 700 μm, even more preferably 50 to 600 μm. When the thickness is 20 μm or more, when adjacent optical semiconductor devices are separated from each other, it is even less likely that sheets will be damaged or sheets of adjacent optical semiconductor devices will adhere. 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 even thinner.

The ratio of the thickness (total thickness) of the radiation-curable resin layer to 100% of the total thickness of the optical semiconductor device sealing sheet (excluding the release liner and surface protection film) is 5 to 90%. Preferably, it is more preferably 10 to 85%, still more preferably 40 to 80%. When the above ratio is 5% or more, when separating adjacent optical semiconductor devices from each other, sheet loss and adhesion of sheets of adjacent optical semiconductor devices are even less likely 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 even thinner.

After curing, the radiation-curable resin layer preferably has a hardness of 1.2 MPa or more, more preferably 1.4 MPa or more, still more preferably 2 0 MPa or more, more preferably 15.0 MPa or more, particularly preferably 50.0 MPa or more. The hardness obtained by the nanoindentation method is determined 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. Determined from the indentation depth curve. When the hardness is 1.2 MPa or more, the radiation-curable resin layer will have appropriate hardness after curing, and when separating adjacent optical semiconductor devices in a tiling state, damage to the sheets and adjacent This makes it even more difficult for sheets of optical semiconductor devices to adhere to each other.

The radiation-curable resin layer preferably has a hardness of less than 1.4 MPa, more preferably 1.3 MPa or less, even more preferably 1.3 MPa or less, in the cross section of the layer, measured by nanoindentation at a temperature of 23° C., before curing. .2 MPa or less. When the hardness is less than 1.4 MPa, the radiation-curable resin layer is relatively soft before curing, and has excellent sealing properties when sealing an optical semiconductor element.

The radiation-curable resin layer preferably has a hardness ratio [after curing/before curing] of 1.0 or more after curing to that before curing 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, further preferably 5.0 or more, particularly preferably 10.0 or more. When the ratio is 1.3 or more, the sealing portion has better sealing properties for the optical semiconductor element before the radiation-curable resin layer is cured, and stickiness on the side surface is further suppressed after the radiation-curable resin layer is cured.

The arithmetic mean height Sa of the cross section in the thickness direction of the radiation-curable resin layer after curing is preferably 85 μm or less, more preferably 70 μm or less, even more preferably 40 μm or less, still more preferably 10 μm or less, and even more preferably is 4 μm or less, particularly preferably 1 μm or less. When the arithmetic mean height Sa is 85 μm or less, the surface roughness of the side surface of the cured sealing layer, which is a layer after the cure of the exposed radiation-curable resin layer, is small, and when separating adjacent optical semiconductor devices, the sheet It is even more difficult for the sheets of adjacent optical semiconductor devices to be damaged or adhered to each other.

The thickness of the radiation-non-curable adhesive layer located on the surface of the optical semiconductor element sealing sheet (that is, the surface of the sealing part) 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 sealing sheet to the optical semiconductor element and the substrate is more excellent. The thickness is preferably 500 μm or less, more preferably 300 μm or less, even more preferably 200 μm or less. When the thickness is 500 μm or less, when adjacent optical semiconductor devices are separated from each other, sheet damage and adhesion of sheets of adjacent optical semiconductor devices are less likely to occur. Moreover, when dicing an optical semiconductor device, stickiness of the dicing portion can be further suppressed, and an optical semiconductor device with good appearance can be manufactured.

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

The sealing portion may include a layer containing a colorant. By having such a configuration, when the optical semiconductor device is tiled and applied to a display, when the optical semiconductor device is used, color mixing of the light emitted by each optical semiconductor element is suppressed, and the optical semiconductor device is The appearance of the display can be adjusted when not in use. The layer containing the colorant 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 radiation non-curable adhesive layer, or any other layer other than these, but the radiation curable resin layer and/or the radiation non-curable adhesive layer may be It is preferable that the curable adhesive layer is a layer containing a colorant, and it is more preferable that the radiation-non-curable adhesive layer is a layer containing a colorant.

As the colorant, a black colorant is preferable. As the black colorant, known or commonly used colorants (pigments, dyes, etc.) for producing a black color can be used. For example, carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, etc.) can be used. , 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, zirconium nitride, etc. Only one type of black colorant may be used, or two or more types may be used. Further, a colorant that functions as a black colorant by combining a colorant exhibiting a color other than black may be used.

<Base material part>
The base material part serves as a support for the sealing part, and by including the base material part, the sheet for encapsulating an optical semiconductor element has excellent handling properties. The base material portion may be a single layer, or may be a multilayer having the same or different compositions, thicknesses, etc. When the base material part is multi-layered, each layer may be bonded together by another layer such as an adhesive layer. In addition, when sealing an optical semiconductor element using an optical semiconductor element sealing sheet, the base material layer used for the base material part is the part that is attached to the substrate provided with the optical semiconductor element together with the sealing part. The "base material" does not include a release liner that is peeled off when the optical semiconductor device sealing sheet is used (during application) and a surface protection film that merely protects the surface of the base material.

Examples of the base layer constituting the base portion include glass and plastic base materials (especially plastic films). Examples of the resin constituting the plastic base material 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 homopolyprolene. , 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; Polyetheretherketone; Polyetherimide; Polyamide such as aramid and wholly aromatic polyamide; Polyphenylsulfide; Fluororesin; Polyvinyl chloride; Polyvinylidene chloride; Cellulose resin such as triacetylcellulose (TAC) ; silicone resin; acrylic resin such as polymethyl methacrylate (PMMA); polysulfone; polyarylate; polyvinyl acetate. The above resins may be used alone or in combination of two or more.

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

The plastic film preferably contains a polyester resin and/or a polyimide resin as a main component (component having the highest mass ratio among the constituent resins). By having such a configuration, the sheet for encapsulating an optical semiconductor element has excellent heat resistance, can suppress thermal expansion of the sheet for encapsulating an optical semiconductor element in a high-temperature environment, and improves dimensional stability. Furthermore, since rigidity can be imparted to the sheet, handling and holding properties are improved.

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

The base material portion preferably 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 poor in support and handling, and by using them in combination with the above plastic films, the advantages of both can be utilized. In this case, it is particularly preferable that the plastic film is on the side of the sealing part in the base part.

The base material portion preferably includes a layer having anti-glare and/or anti-reflection properties. The above-mentioned layer having anti-glare properties and/or anti-reflection properties can be formed by applying anti-glare treatment and/or anti-reflection treatment to at least one surface of the base material layer. can get. The anti-glare treatment layer and the anti-reflection treatment layer may be the same layer or may be different layers. The anti-glare treatment and the anti-reflection treatment can be carried out using known or commonly used methods.

The surface of the base portion on the side where the sealing portion is provided may be subjected to, for example, corona discharge treatment, plasma treatment, sand mat processing treatment, ozone exposure treatment, etc., for the purpose of improving adhesion and retention with the sealing portion. Physical treatments such as flame exposure treatment, high-voltage electric shock exposure treatment, and ionizing radiation treatment; chemical treatments such as chromic acid treatment; and surface treatments such as adhesion-facilitating treatment with a coating agent (undercoat). The surface treatment for improving adhesion is preferably applied to the entire surface of the base member on the side of the sealing part.

In the optical semiconductor element sealing sheet 1 shown in FIG. It is pasted together through. Further, the surface of the optical film 21 facing the plastic film 23 is subjected to anti-glare treatment and anti-reflection treatment.

The thickness of the base material portion is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of excellent support function and surface scratch resistance. The thickness of the base material portion 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 part, and is peeled off from the sheet when bonding the optical semiconductor element sealing sheet 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 films and papers whose surface is coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate release agent. It will be done.

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

<Sheet for encapsulating optical semiconductor elements>
The ratio of the total thickness of the base material part and the sealing part in the optical semiconductor element sealing sheet is the thickness of the optical semiconductor element sealing sheet (excluding the release liner and surface protection 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 base material part to the surface of the sealing part, including the base material part and the sealing part, is within the above range.

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

An embodiment of the method for manufacturing an optical semiconductor device sealing sheet of the present invention will be described. For example, the optical semiconductor element sealing sheet 1 shown in FIG. 1 can be produced by the following method. First, a radiation-curable resin layer 31 is formed on the plastic film 23 constituting the base portion 2 . The radiation curable resin layer 31 is formed by coating the resin composition forming the radiation curable resin layer 31 on one side of the plastic film 23 to form a resin composition layer, and then removing the solvent by heating or thermally curing the resin composition. It can be produced by solidifying the resin composition layer by performing curing other than radiation irradiation. When increasing the thickness of the radiation-curable resin layer 31, a radiation-curable resin layer prepared in the same manner on the release-treated surface of a release liner is added to the radiation-curable resin layer formed on the plastic film 23. They may be stacked on top of each other.

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 of an emulsion type, a solvent type (solution type), a hot melt type, or the like. Among these, a solvent type is preferable because it is easy to obtain an adhesive layer with excellent productivity.

The resin composition may contain the crosslinking agent and the photopolymerization initiator (photoinitiator) in addition to the radiation-polymerizable functional group-containing polymer and the other components. When the above-mentioned crosslinking agent is included, crosslinking by the above-mentioned crosslinking agent proceeds when heating the above-mentioned resin composition layer to form a radiation-curable resin layer. Furthermore, when the photopolymerization initiator is included, polymerization of the radiation-polymerizable functional group is promoted when the radiation-curable resin layer is cured. The crosslinking agent and the photopolymerization initiator may each be used alone or in combination of two or more.

On the other hand, a radiation-non-curable adhesive layer 32 is formed on the release-treated surface of a release liner 4 prepared separately. The radiation non-curable adhesive layer 32 is formed by coating the adhesive composition forming the radiation non-curing adhesive layer 32 on the release-treated surface of the release liner 4 to form an adhesive composition layer, and then heating the adhesive composition layer. The pressure-sensitive adhesive composition layer can be produced by solidifying the pressure-sensitive adhesive composition layer by removing the solvent and curing the pressure-sensitive adhesive composition layer. Then, the radiation-non-curable adhesive layer is laminated on the radiation-curable resin layer. In this way, a laminate having the structure [plastic film 23/radiation curable resin layer 31/radiation non-curable adhesive layer 32/release liner 4] is obtained.

The adhesive composition forming the radiation-non-curable adhesive layer may be in any form. For example, the adhesive composition may be of an emulsion type, a solvent type (solution type), an active energy ray-curable type, a heat melt type (hot melt type), or the like. Among these, solvent-type and active energy ray-curable pressure-sensitive adhesive compositions are preferred from the viewpoint that it is easy to obtain a pressure-sensitive 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-curable adhesive layer 32, and then the optical film 21 is formed on the adhesive layer 22. It can be produced by bonding them together. Then, the release liner is peeled off to expose the adhesive layer 22, and the adhesive layer 22 is bonded 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 adhesive composition, for example, any known or commonly used coating method can be employed, such as roll coating, screen coating, and gravure coating. Moreover, lamination of various layers can be performed using a known roller or laminator. In this way, the optical semiconductor element sealing sheet 1 shown in FIG. 1 can be produced.

Note that the sheet for encapsulating optical semiconductor devices of the present invention is not limited to the above-mentioned method, and when the base material part is composed of multiple layers, the base material part is first prepared, and the radiation curable material is applied to the base material part. It can be produced by sequentially laminating a resin layer and a non-radiation curable adhesive layer in an appropriate combination.

Using the sheet for encapsulating an optical semiconductor device of the present invention, the sealing portion of the sheet for encapsulating an optical semiconductor device of the present invention is pasted onto a substrate on which an optical semiconductor device is arranged, and the optical semiconductor device is sealed by the sealing portion. By sealing, an optical semiconductor device can be obtained. Specifically, first, the release liner is peeled off from the optical semiconductor element sealing sheet of the present invention to expose the sealing portion. Then, the optical semiconductor element sealing of the present invention is applied to the substrate surface on which the optical semiconductor element is arranged, of the optical member comprising a substrate and an optical semiconductor element (preferably a plurality of optical semiconductor elements) arranged on the substrate. When the optical member includes a plurality of optical semiconductor elements, the sealing part is arranged so as to fill the gap between the plurality of optical semiconductor elements. The optical semiconductor devices are sealed together. In this way, an optical semiconductor element can be sealed using the optical semiconductor device sealing sheet of the present invention. Moreover, an optical semiconductor element may be sealed using the sheet for encapsulating an optical semiconductor device of the present invention by bonding them together in a reduced pressure environment or while applying pressure. Examples of such a method include methods disclosed in JP-A-2016-29689 and JP-A-6-97268.

[Optical semiconductor device]
An optical semiconductor device can be manufactured using the optical semiconductor element sealing sheet of the present invention. An optical semiconductor device manufactured using the optical semiconductor device sealing sheet of the present invention includes a substrate, an optical semiconductor device disposed on the substrate, and an optical semiconductor device of the present invention that seals the optical semiconductor device. A cured product obtained by curing the sealing sheet. The above-mentioned cured product is a cured product obtained by curing the sheet for encapsulating an optical semiconductor element of the present invention by radiation irradiation, and specifically, the radiation-curable resin layer in the sheet for encapsulating an optical semiconductor element of the present invention is cured by radiation irradiation. A cured sealing layer is provided.

Examples of the optical semiconductor device 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-mentioned optical semiconductor device, the sheet for encapsulating optical semiconductor elements of the present invention has excellent followability to irregularities when the optical semiconductor element is used as a convex part and the gaps between a plurality of optical semiconductor elements are used as recesses. In order to have excellent embedding properties, it is preferable to seal a plurality of optical semiconductor elements at once.

FIG. 2 shows an embodiment of an optical semiconductor device using the optical semiconductor element sealing sheet 1 shown in FIG. The optical semiconductor device 10 shown in FIG. 2 includes a substrate 5, a plurality of optical semiconductor elements 6 arranged on one surface of the substrate 5, and a cured product of an optical semiconductor element sealing sheet for sealing the optical semiconductor elements 6. 1'. The cured product 1' of the optical semiconductor element sealing sheet is a cured sealing layer 31 formed by peeling off the release liner 4 from the optical semiconductor element sealing sheet 1 and curing the radiation curable resin layer 31 by radiation irradiation. ' was formed. The plurality of optical semiconductor elements 6 are collectively sealed in a sealing portion. The non-radiation curable adhesive layer 32 in the sealing portion follows the uneven shape formed by the plurality of optical semiconductor elements 6, adheres closely to the optical semiconductor element 6 and the substrate 5, and embeds the optical semiconductor element 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 sealed by the hardening sealing layer 31'. is sealed in. The above-mentioned 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 hardened sealing layer 31'. Alternatively, 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, in the optical semiconductor device, the optical semiconductor element is sealed with a radiation-non-curable adhesive layer and a cured sealing layer that is a cured product of a radiation-curable resin layer. For this reason, the optical semiconductor element is in close contact with the sealing part, and the optical semiconductor element has excellent sealing properties, and the adhesiveness of the side surface of the cured sealing layer is low, so in the tiled state, adjacent When optical semiconductor devices are separated from each other, they can be easily separated, and sheet defects and adhesion of sheets of adjacent optical semiconductor devices are less likely to occur.

The above-mentioned optical semiconductor device may be one in which individual optical semiconductor devices are tiled. That is, the optical semiconductor device may be one in which a plurality of optical semiconductor devices are 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, four in the vertical direction and four in the horizontal direction, are arranged in a tile shape (tiling) in the planar direction. At the boundary 20a between two adjacent optical semiconductor devices 10, the optical semiconductor devices 10 are adjacent to each other, but they can be easily separated, resulting in damage to the side surface of the sealing part or damage to one of the adjacent optical semiconductor devices. On the other hand, the defective resin is less likely to adhere to the side surface of the sealing portion.

The optical semiconductor device is preferably a backlight for a liquid crystal screen, and particularly preferably a full-surface direct type backlight. Moreover, an image display device can be obtained by combining the above-described backlight and a 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 a light emission control signal to each LED element is laminated on the substrate. LED elements that emit red (R), green (G), and blue (B) light 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, reducing the visibility of the image. Furthermore, the light emitted by each LED element of each color of RGB is mixed, resulting in a decrease in contrast.

Further, it is preferable that the optical semiconductor device is a self-luminous display device. Moreover, an image display device can be obtained by combining the above self-luminous display device and a display panel as necessary. When the optical semiconductor device is a self-luminous display device, the optical semiconductor element is an LED element. Examples of the self-luminous display device include an organic electroluminescence (organic EL) display device. For example, in the self-luminous display device, a metal wiring layer for sending a light emission control signal to each LED element is laminated on the substrate. LED elements that emit light of red (R), green (G), and blue (B) colors are alternately arranged on a substrate with metal wiring layers interposed therebetween. 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 optical semiconductor element sealing sheet of the present invention has an optical semiconductor device that is used by being folded, for example, a foldable image display device (flexible display) (particularly a foldable image display device (foldable display)). It can be used for optical semiconductor devices. Specifically, it can be used for foldable backlights, foldable self-luminous display devices, and the like.

The sheet for encapsulating optical semiconductor elements of the present invention has excellent embedding properties for optical semiconductor elements, and therefore can be preferably used in both cases where the optical semiconductor device is a mini LED display device and a micro LED display device. Can be done.

[Method for manufacturing optical semiconductor device]
The optical semiconductor device includes, for example, a substrate, an optical semiconductor element disposed on the substrate, and the radiation-curable resin layer of the optical semiconductor element sealing sheet of the present invention for sealing the optical semiconductor element. The optical semiconductor device can be manufactured by a manufacturing method including at least a hardened product and a dicing step of dicing a laminate including the hardened product to obtain an optical semiconductor device. The above-mentioned cured product is a cured product obtained by curing the sheet for encapsulating an optical semiconductor element of the present invention by radiation irradiation, and specifically, the radiation-curable resin layer in the sheet for encapsulating an optical semiconductor element of the present invention is cured by radiation irradiation. A hardened sealing layer is provided.

When curing the radiation-curable resin layer by irradiating it with radiation, curing is inhibited on the side surfaces where oxygen is present, and curing tends to be insufficient. On the other hand, according to the above-mentioned manufacturing method including the above-mentioned dicing step, regarding a laminate including a cured product of an optical semiconductor element sealing sheet including a cured sealing layer in which the above-mentioned radiation-curable resin layer is cured by radiation irradiation. By cutting off and removing the side edges that are insufficiently cured in the dicing step, it is possible to obtain an optical semiconductor device in which a region that is sufficiently cured and has reduced adhesion is exposed on the side surface. In the optical semiconductor devices manufactured in this way, the adhesion of the side surfaces of the radiation-curable resin layer after curing is sufficiently reduced, so when adjacent optical semiconductor devices are separated in a tiling state, the sheet may be damaged. Also, adhesion of sheets of adjacent optical semiconductor devices is less likely to occur.

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

The above manufacturing method includes, before the radiation irradiation step, bonding the optical semiconductor element sealing sheet to the optical semiconductor element provided on the substrate, and sealing the optical semiconductor element with the sealing part. It may also include a sealing step.

Further, 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 planar direction. Hereinafter, 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 with appropriate reference.

(Sealing process)
In the above-mentioned sealing step, the optical semiconductor element sealing sheet of the present invention is bonded to the substrate on which the optical semiconductor element is arranged, and the optical semiconductor element is sealed by the sealing portion. In the above-mentioned sealing process, specifically, as shown in FIG. The optical semiconductor element sealing sheet 1 is attached to the surface of the substrate 5 on which the optical semiconductor element 6 is arranged, and the optical semiconductor element 6 is sealed as shown in FIG. Embed it in the stop part 3. As shown in FIG. 4, the substrate 5 used for bonding extends wider in the plane direction than the substrate 5 in the optical semiconductor device 10 shown in FIG. is not placed. Further, the optical semiconductor element sealing sheet 1 to be bonded extends wider in the plane direction than the substrate 5 used for bonding. That is, the area of the surface of the optical semiconductor element sealing sheet 1 facing the substrate 5 to be bonded together in the sealing process is the area of the surface of the substrate 5 facing the optical semiconductor element sealing sheet 1 to be bonded together in the sealing process. larger than the area of This allows sufficient curing to progress in the subsequent radiation irradiation step in the region of the laminate of the optical semiconductor element sealing sheet 1 and the substrate 5 that will be used for the optical semiconductor device. This is because the vicinity of the edges of the substrate 5 where there is a possibility that the curing is insufficient will be diced and removed in a later dicing step.

The temperature during the above bonding is, for example, within the range of room temperature to 110°C. Further, during the above bonding, pressure may be reduced or increased. It is possible to suppress the formation of a gap between the sealing part and the substrate or the optical semiconductor element due to pressure reduction or pressurization. Moreover, in the said sealing process, it is preferable to bond the optical semiconductor element sealing sheet together under reduced pressure, and to apply pressure after that. The pressure for reducing the pressure is, for example, 1 to 100 Pa, and the time for reducing the pressure 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 process)
In the radiation irradiation step, radiation is applied to a laminate (for example, a laminate obtained in the encapsulation step) in which the optical semiconductor element sealing sheet is bonded to the substrate on which the optical semiconductor element is arranged. is irradiated to cure the radiation-curable resin layer. In the radiation irradiation step, specifically, 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 ' is obtained. As mentioned above, examples of the radiation include electron beams, ultraviolet rays, α rays, β rays, γ rays, and X rays. Among these, ultraviolet light is preferred. The temperature during radiation irradiation is, for example, in the range from 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 (e.g. , the laminate that has undergone the radiation irradiation step) is diced. Here, in the laminate subjected to the dicing process, the cured product 1' of the optical semiconductor element sealing sheet and the substrate 5 extend more widely in the plane direction than the optical semiconductor device 10 finally obtained. There is. In the dicing step, the cured product of the optical semiconductor element sealing sheet and the side edges of the substrate are diced and removed. Specifically, dicing is performed at the position indicated by the chain line shown in FIG. 7, and the side edges are removed. The above-mentioned dicing can be performed by a known or commonly used method, for example, by using a dicing blade or by laser irradiation. In this way, for example, the optical semiconductor device 10 shown in FIG. 2 can be manufactured.

Here, in the above manufacturing method, it is important to perform dicing in a state where the radiation-curable resin layer obtained by, for example, going through the above-mentioned radiation irradiation step is cured. If dicing is performed with the radiation-curable resin layer not yet cured, when the side edges of the optical semiconductor element sealing sheet are pulled apart and removed after dicing, the side edges that are removed and the light that remains are The radiation-curable resin layers in the semiconductor device have high adhesion and attract each other, causing damage to the radiation-curable resin layer in the remaining optical semiconductor device. There may be a problem that a part of the radiation-curable resin layer is transferred and adhered. On the other hand, by providing the above-mentioned dicing process in which dicing is performed in a state where the radiation-curable resin layer is cured, the radiation-curable resin layer is cured and becomes a hardened sealing layer, so that the side surface of the dicing part is Adhesion is low, and the occurrence of the above-mentioned problems can be suppressed.

Furthermore, when the radiation-curable resin layer is cured by irradiation with radiation, curing is inhibited on the side surfaces where oxygen is present, 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 edges that are insufficiently cured are cut off and removed in the dicing step, so that the side surface is It is possible to obtain an optical semiconductor device that is sufficiently cured and has reduced adhesion. In optical semiconductor devices manufactured in this way, the adhesion of the side surfaces is sufficiently reduced after the radiation-curable resin layer is cured, so when separating adjacent optical semiconductor devices in a tiling state, the sheet Defects and adhesion of adjacent optical semiconductor device sheets are less likely to occur. On the other hand, if the above-mentioned dicing process is not provided, the insufficiently cured side surfaces will come into contact with adjacent optical semiconductor devices during tiling, so when attempting to separate adjacent optical semiconductor devices, the side surfaces may may cause damage to the radiation-curable resin layer in one optical semiconductor device, or a portion of the radiation-curable resin layer in the other optical semiconductor device may be transferred and adhered to one optical semiconductor device. Problems such as

(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 a planar direction. In this way, for example, the optical semiconductor device 20 shown in FIG. 3 can be manufactured. The optical semiconductor device obtained by tiling has excellent sealing properties of the optical semiconductor element, but when adjacent optical semiconductor devices are separated from each other, sheets are less likely to be damaged or sheets of adjacent optical semiconductor devices are less likely to adhere.

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

Example 1
<TAC film/binder adhesive layer>
As monomer components, 69.7 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of 2-methoxyethyl acrylate (MEA), 13 parts by mass of 2-hydroxyethyl acrylate (HEA), N-vinyl-2- 6 parts by mass of pyrrolidone (NVP), 1.3 parts by mass of N-hydroxyethylacrylamide (HEAA), 0.1 part by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 200 parts by mass of ethyl acetate as a polymerization solvent. Part by mass was put into a separable flask, and stirred for 1 hour while introducing nitrogen gas. After removing oxygen in the polymerization system in this manner, the temperature was raised to 63° C., the reaction was continued for 10 hours, and ethyl acetate was added to obtain an acrylic polymer solution with a solid content concentration of 30% by mass. To 100 parts by mass of the above acrylic polymer, 0.2 parts by mass of an isocyanate crosslinking agent (trade name "Takenate D110N", manufactured by Mitsui Chemicals, Inc.) as a crosslinking agent, and γ-glycidoxypropyl as a silane coupling agent. 0.15 parts by mass of trimethoxysilane (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.), a polyol in which propylene oxide is added to ethylenediamine as a crosslinking accelerator (trade name "EDP-300", manufactured by ADEKA Co., Ltd.) ) 0.2 part by mass was added to prepare an adhesive composition (solution). Next, the above 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. Then, the mixture was dried by heating at 60° C. for 1 minute and at 155° C. for 1 minute under normal pressure to obtain a double-sided adhesive sheet as a binder adhesive layer. Then, using a hand roller, apply the binder to the untreated surface of a triacetyl cellulose (TAC) film (trade name "DSR3-LR", manufactured by Dai Nippon Printing Co., Ltd., total thickness 45 μm, anti-glare/anti-reflection treatment). The adhesive surfaces of the adhesive layers were pasted together to prevent air bubbles from entering. In this way, a laminate having the structure of [TAC film/binder adhesive layer/release liner] was produced.

<PET film/UV curable adhesive layer/Radiation non-curable adhesive layer>
(UV 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 1L round-bottom separable flask, a separable cover, a separating funnel, a thermometer, a nitrogen introduction 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 atmosphere was replaced with nitrogen at room temperature for 6 hours while stirring. Thereafter, polymerization was carried out by holding the mixture at 65° C. for 4 hours and at 75° C. for 2 hours while stirring under nitrogen flow, thereby obtaining a resin solution.
The resulting resin solution was then cooled to room temperature. Then, 5.74 parts by mass of 2-isocyanatoethyl methacrylate (MOI) (trade name "Karens MOI", manufactured by Showa Denko K.K.) was added to the resin solution as a compound having a polymerizable carbon-carbon double bond. Ta. Furthermore, 0.03 parts by mass of dibutyltin(IV) dilaurate (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 diluting solvent, the solid content was adjusted to 20 to 40% by mass to obtain an adhesive solution (1).

This adhesive solution (1) was applied onto 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. The adhesive layer (1) was formed by heating and drying at 50° C. for 1 minute and 125° C. for 5 minutes under normal pressure. On the other hand, the 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 coated and dried by heating at 50° C. for 1 minute and 125° C. for 5 minutes under normal pressure to form an ultraviolet curable 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 are rubbed together using a hand roller to prevent air bubbles from entering. They were bonded together to form one UV-curable adhesive layer. The release liner was then peeled off. In this way, a laminate having the structure of [PET film/ultraviolet curable 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 1L round-bottom separable flask, a separable cover, a separating funnel, a thermometer, a nitrogen introduction 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 purged with nitrogen at room temperature for 6 hours while stirring. Thereafter, polymerization was carried out by holding the mixture at 65° C. for 4 hours and at 75° C. for 2 hours while stirring under nitrogen flow, thereby obtaining a resin solution.
To the obtained 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 respect to 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 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 mixture was heated at 125°C under normal pressure. The mixture was dried by heating for 2 minutes to form a radiation-curable adhesive layer.

(PET film/UV curable adhesive layer/Radiation non-curable adhesive layer)
The above-mentioned radiation-non-curable adhesive layer is applied to the UV-curable adhesive layer surface of the laminate having the structure of [PET film/UV-curable adhesive layer] using a hand roller to prevent air bubbles from entering. Combined. In this way, a laminate having the structure of [PET film/ultraviolet curable adhesive layer/radiation non-curable adhesive layer/release liner] was produced.

<Sheet for encapsulating optical semiconductor elements>
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 separated from [PET film/ultraviolet curable adhesive layer/radiation non-curable adhesive layer]. /Release liner] was bonded to the PET film surface of the laminate using a hand roller to prevent air bubbles from entering. Example 1 was then aged at 50° C. for 48 hours and had 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 encapsulating an optical semiconductor device was prepared.

Examples 2 to 5
In preparing the ultraviolet curable adhesive layer, the same procedure as in Example 1 was carried out, except that the amounts of 2-isocyanatoethyl methacrylate (MOI) and dibutyltin (IV) dilaurate were changed as shown in the table. Sheets for encapsulating optical semiconductor devices in Examples 2 to 5 were each produced.

Comparative example 1
The adhesive solution (2) prepared in Example 1 was applied onto the treated surface of a PET film (trade name "T912E75 (UE80-)", manufactured by Mitsubishi Chemical Corporation, thickness 75 μm) to a thickness of 125 μm after drying. The adhesive layer (1) was formed by heating and drying at 50° C. for 1 minute and 125° C. for 5 minutes under normal pressure. On the other hand, the 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. Then, the mixture was 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 adhesive layer (2).

Then, the adhesive layer surfaces of the non-radiation curable adhesive layer (1) formed on the PET film and the non-radiation curable adhesive layer (2) formed on the release liner are rubbed together using a hand roller to prevent air bubbles from entering. These were bonded together to form one radiation-curable adhesive layer. In this way, a laminate having the structure of [PET film/radiation non-curable adhesive layer/release liner] was produced.

The release liner was peeled off from the laminate having the structure [TAC film/binder adhesive layer/release liner] produced in Example 1, and the exposed binder adhesive layer surface was removed from the [PET film/radiation non-curable adhesive layer/ The PET film surface of the laminate having the structure of "Release liner" was bonded to the PET film surface using a hand roller so as to prevent air bubbles from entering. Thereafter, aging was performed at 50° C. for 48 hours, and the optical semiconductor device encapsulation of Comparative Example 1 had a layer structure of [TAC film/binder adhesive layer/PET film/radiation non-curable adhesive layer/release liner]. A sheet was produced.

Comparative example 2
In preparing the ultraviolet curable adhesive layer, the adhesive solution of Example 1 ( An adhesive solution (3) was obtained in the same manner as in 1).
Then, the prepared adhesive solution (3) is applied onto 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 is 125 μm. The adhesive was coated in the same manner as above and dried under normal pressure by heating at 50° C. for 1 minute and 125° C. for 5 minutes to form an ultraviolet curable adhesive layer (3). On the other hand, the 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, It was dried by heating at 50° C. for 1 minute and at 125° C. for 5 minutes under normal pressure to form an ultraviolet curable 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 are rubbed together using a hand roller to prevent air bubbles from entering. They were bonded together to form one UV-curable adhesive layer. In this way, a laminate having the structure of [PET film/ultraviolet curable 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 removed from the [PET film/UV curable adhesive layer/release liner] layer. A hand roller was used to adhere the laminate to the PET film surface of the laminate having the structure of ``liner'' so as to prevent air bubbles from entering. Thereafter, the sheet for encapsulating optical semiconductor elements of Comparative Example 2 was aged at 50° C. for 48 hours and had a layer structure of [TAC film/binder adhesive layer/PET film/UV curable adhesive layer/release liner]. was created.

<Evaluation>
The following evaluations were performed on the ultraviolet curable adhesive layers and optical semiconductor device sealing sheets obtained in Examples and Comparative Examples. The results are shown in the table.

(1) Hardness by nanoindentation method The hardness of the surface of the optical semiconductor device sealing sheets obtained in Examples and Comparative Examples before and after curing of the ultraviolet curable adhesive layer was determined by nanoindentation method. Measurements were made. The ultraviolet curable adhesive layer was cured by irradiating ultraviolet light from the TAC film side under the following ultraviolet irradiation conditions. Then, after freezing the optical semiconductor device sealing sheet before and after curing the UV-curable adhesive layer at -40°C to -30°C for 10 to 15 minutes, the sheets were thickened using an ultramicrotome under the freezing conditions. The cross section of the ultraviolet curable adhesive layer was exposed by cutting in the transverse direction. Then, after fixing the optical semiconductor element sealing sheet with an exposed cross section to the metal stage attached to the device by solidifying it with Pentel correction fluid (product number "XEZL1-W"), polyimide was applied to the window of the device, etc. Evaluation was performed after pasting a film to block light. Using a nanoindenter (trade name "TriboIndenter", manufactured by HYSITRON Inc.), nanoindentation measurements were performed on the surface of the ultraviolet curable 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 equipment: Product name "Ultraviolet illuminometer UT-101", manufactured by Ushio Inc.)
Irradiation time: 100 seconds Integrated light amount: 5000mJ/cm ²
<Nanoindentation measurement conditions>
Indenter used: Berkovich (triangular pyramid type)
Measurement method: Single indentation measurement Measurement temperature: 23℃
Indentation depth setting: 3.0μm
Load speed: 500nm/s
Unloading speed: 500nm/s

(2) Dicing evaluation Regarding the optical semiconductor element sealing sheets obtained in the examples and comparative examples, a release liner was applied to the patterned surface of the substrate (product name "Lead-free universal board ICB93SGPBF", manufactured by Sunhayato Co., Ltd.). The entire surface of the adhesive layer that was peeled off and exposed was bonded together using a hand roller to prepare a test sample. Note that the area of the adhesive layer of the optical semiconductor element sealing sheet is larger than the area of the substrates to be bonded together. The bonding was carried out under an environment of a temperature of 22° C. and a humidity of 50% to prevent air bubbles from entering. 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 adhesive layer. Note that the test sample using the optical semiconductor device sealing sheet of Comparative Example 1 which did not have an ultraviolet curable 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 equipment: Product name "Ultraviolet illuminometer UT-101", manufactured by Ushio Inc.)
Irradiation time: 100 seconds Integrated light amount: 5000mJ/cm ²

After irradiation with ultraviolet rays, a dicing tape (trade name "NBD-5172K", manufactured by Nitto Denko Corporation) was attached to the surface of the substrate on the side of the test sample to which the optical semiconductor element sealing sheet was not attached. A dicing ring for dicing was attached to the adhesive side of the dicing tape. After pasting, it was left for 30 minutes under light shielding and at a temperature of 22°C. Thereafter, the test sample and the dicing tape laminate were subjected to blade dicing at a position 5 mm inward from the side edge of the substrate under the following dicing conditions.
<Dicing conditions>
Dicing device: 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: 85μm
Water amount: 1.5L/min Dicing interval: 10mm
Distance of one dicing: Total length of test sample

Note that the blade used for dicing was one that had been subjected to dress dicing using the following method.
A dicing ring and a board (product name ``DRESSER BOARD BGCA0172'', manufactured by DISCO Corporation) are attached to the adhesive layer of a dicing tape (product name ``NBD-7163K'', manufactured by Nitto Denko Corporation), and a A workpiece was created. Next, the obtained workpiece was diced under the following dress dicing conditions to obtain a blade for the blade dicing described above.
<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: 500μm
Water amount: 1.5L/min Distance of one dicing: Total length of board Dicing interval: 1mm increments Number of dicing: 100 times

After blade dicing, ultraviolet rays were irradiated from the dicing tape base material side under the following ultraviolet irradiation conditions (2) to reduce the peel strength of the dicing tape against 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 equipment: Product name "Ultraviolet illuminometer UT-101", manufactured by Ushio Inc.)
Irradiation time: 10 seconds Integrated light amount: 500mJ/cm ²

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

(3) Arithmetic mean height Sa of cross section
The laminate of the test sample and the substrate, which had been cut into strips in the above dicing evaluation, was peeled off from the dicing tape. Then, the arithmetic mean height Sa of the cross section of the cured product of the exposed ultraviolet curable resin layer was measured. In addition, for Comparative Example 1 which does not have an ultraviolet curable resin layer, the arithmetic mean height Sa of the cross section of the radiation non-curable adhesive layer was measured. 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 pasted onto the exposed surface (the surface not in contact with the Si mirror wafer) of the double-sided adhesive tape using tweezers. The dicing cut surface and the double-sided adhesive tape were pasted together so that the outermost surface (the surface furthest from the double-sided adhesive tape) was the last diced cut surface. The finally diced cut surface was observed and measured using a laser microscope (product name "VK-X150", manufactured by Keyence Corporation). The PC software used was "Observation Application VK-H1XV2 Version 2.5.0.0" (manufactured by Keyence Corporation). The objective lens used was "20X/0.46 OFN25 WD 3.1" (manufactured by Nikon Corporation). The roughness of the dicing cut surface was measured using the "Shape Measurement" PC software with the following measurement settings.
<Measurement settings>
Measurement mode: Transparent object (top surface)
Measurement size: Standard (1024 x 768)
Measurement quality: High precision Pitch: 0.75μm

Then, the three-dimensional data obtained by the measurement was saved. Note that the cross-section of the layer to be measured was shown from the left end to the right end of the screen (the cross-section of a layer with a thickness of 250 μm or less was within the screen). After that, I performed "skew correction" in the "image processing" section of the PC software. As the correction method, surface inclination correction (profile) was selected, and with the centers of the two lines aligned with the layer center of the obtained observation image, the inclination correction was performed so that the cut plane was horizontal. After the tilt was corrected, the corrected three-dimensional data was saved. Next, the three-dimensional data was analyzed using analysis PC software "Multi-file analysis application VK-H1XM version 1.1.22.87" (manufactured by Keyence Corporation). "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) String evaluation Two laminates of the test sample and the substrate, which had been cut into strips in the above dicing evaluation, were peeled off from the dicing tape. Next, the cut surfaces of the two laminates exposed by dicing were adhered to each other, and the laminate was left in this state for 24 hours in an environment at a temperature of 50°C. Thereafter, the two adhered strips were taken out and left in an environment with a temperature of 22° C. and a humidity of 50% for 3 hours. After that, we tried to peel off the glued cut surfaces by hand, and those that could not be peeled off, or those that could be peeled off but where noticeable stringiness of the adhesive layer was observed, were designated as "D". Those that were able to be peeled off but with slight stringing of the adhesive layer were marked as "C", and those that required force to be peeled off but could be peeled off without any stringing of the adhesive layer were marked as "B". The adhesive layer was evaluated as "A" if it could be peeled off without any particular force and without any stringiness of the adhesive layer.

As shown in Table 1, the sheet for encapsulating optical semiconductor elements (Example) of the present invention has good results in dicing evaluation, has excellent adhesion of the sheet to optical semiconductor elements and substrates, and has excellent adhesiveness to optical semiconductor elements and substrates. It was evaluated as having excellent anti-static properties. In addition, the results of the stringing evaluation were good, and the adhesion of the sides of the sealing part was low, making it difficult for sheets to break or adhere to adjacent optical semiconductor devices when separating adjacent optical semiconductor devices. It was done.

On the other hand, in the case of not having an ultraviolet curable adhesive layer (Comparative Example 1), the results of stringiness evaluation were poor. Furthermore, in the case of not having a radiation-curable adhesive layer (Comparative Example 2), the results of dicing evaluation were poor, and the sealing performance of the optical semiconductor element was evaluated to be poor.

1 Sheet for optical semiconductor element sealing 1' Cured product of sheet for optical semiconductor element sealing 2 Base material part 21 Optical film 22 Adhesive layer 23 Plastic film 3 Sealing part 31 Radiation curable resin layer 31' Cured sealing 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, the sheet comprising:
comprising a base material part and a sealing part provided on one surface of the base material part for sealing the optical semiconductor element,
The sealing part has a radiation-non-curable adhesive layer and a radiation-curable resin layer,
The sealing part has the radiation-non-curable adhesive layer on the surface of the sealing part that is on the optical semiconductor element side when sealing the optical semiconductor element,
The radiation-curable resin layer is a sheet for encapsulating an optical semiconductor device, and the radiation-curable resin layer contains a polymer having a radiation-polymerizable functional group. The sheet for encapsulating an optical semiconductor element according to claim 1, wherein the radiation-curable resin layer is thicker than the radiation-non-curable adhesive layer. The sheet for encapsulating an optical semiconductor element according to claim 1 or 2, wherein the sealing portion includes a layer containing a colorant. The sheet for encapsulating an optical semiconductor device according to any one of claims 1 to 3, comprising a layer having anti-glare properties and/or anti-reflection properties. The sheet for encapsulating an optical semiconductor device 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. For encapsulating an optical semiconductor device according to any one of claims 1 to 5, wherein 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. sheet. A substrate, an optical semiconductor element disposed on the substrate, and the radiation-curable resin of the optical semiconductor element sealing sheet according to any one of claims 1 to 6, which seals the optical semiconductor element. An optical semiconductor device comprising: a cured product in which the layer is cured. 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. 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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