Workpiece handling sheet and device manufacturing method

Abstract

This workpiece handling sheet 1 includes: a base material 12; and an interface ablation layer 11 which is laminated on one surface side of the base material 12, can hold a workpiece small piece, and is subjected to interface ablation by irradiation with laser light, the workpiece handling sheet 1 being characterized in that the surface resistivity of the surface of the interface ablation layer 11 on the side opposite to the base material 12 is 1.5 × 1013 Ω / sq or less. The workpiece handling sheet is capable of favorably handling small workpiece pieces by suppressing the influence of static electricity.

Description

Work handling sheet and device manufacturing method

[0001] The present invention relates to a work handling sheet that can be used for handling small pieces of workpieces such as semiconductor components and semiconductor devices, and to a method for manufacturing devices using the work handling sheet.

[0002] Semiconductor wafers made of silicon, gallium arsenide, and other materials, as well as various packages, are manufactured in a large diameter state. These are then cut and separated into small element pieces (semiconductor chips) (dicing) and individually peeled off (picked up) before being moved to the next process, the mounting process. During this process, the workpiece, such as a semiconductor wafer, is attached to a semiconductor processing sheet that has a base material and an adhesive layer, and then undergoes processes such as backgrinding, dicing, cleaning, drying, expanding, picking up, and mounting.

[0003] In the pickup and mounting process described above, semiconductor chips are individually picked up from the semiconductor processing sheet using a suction collet and placed in their designated positions. At this time, the semiconductor chips may also be pushed up from the back of the semiconductor processing sheet using a needle, or the semiconductor processing sheet may be expanded to separate the semiconductor chips from each other.

[0004] Incidentally, in recent years, in the development of displays using micro-light-emitting diodes (LEDs), the use of laser irradiation for positioning individual LEDs onto a substrate has been considered. For example, Patent Document 1 describes a method in which multiple LEDs are held on a support via a predetermined layer, and then laser light is irradiated onto the layer to cause ablation of the layer at the irradiated location, thereby separating the LEDs from the support (laser lift-off) and placing them on a wiring substrate. Because laser light has excellent directivity and focusing properties, the irradiation position can be easily controlled, and selective placement can be performed effectively.

[0005] Patent No. 6546278

[0006] In the laser lift-off method described above, even though sufficient ablation occurred, the workpiece fragments sometimes did not separate well from the support. The inventors discovered that this was because the separated workpiece fragments remained in contact with the support or re-adhered due to the effects of static electricity.

[0007] This invention has been made in view of the above circumstances, and aims to provide a work handling sheet that can handle small workpieces well while suppressing the effects of static electricity, and a device manufacturing method using the work handling sheet.

[0008] To achieve the above objective, firstly, the present invention provides a work handling sheet comprising a base material and an interface ablation layer laminated on one side of the base material, capable of holding workpieces, and subjected to interface ablation by laser irradiation, wherein the surface resistivity of the interface ablation layer on the side opposite to the base material is 1.5 × 10 １３ The invention provides a work handling sheet characterized by having a density of Ω / sq or less (Invention 1).

[0009] The work handling sheet according to the above invention (Invention 1) satisfies the above-mentioned surface resistivity conditions, making it less prone to static charge. As a result, the adhesion and re-adhesion of separated workpiece pieces due to the influence of static electricity is suppressed, enabling good separation of workpiece pieces.

[0010] In the above invention (Invention 1), it is preferable to include an antistatic agent (Invention 2).

[0011] In the above invention (Invention 2), it is preferable that the antistatic agent is contained in the substrate (Invention 3).

[0012] In the above invention (Invention 2), it is preferable that the work handling sheet comprises an antistatic layer containing the antistatic agent (Invention 4).

[0013] In the above invention (Invention 4), it is preferable that the antistatic layer is laminated between the substrate and the interface ablation layer (Invention 5).

[0014] In the above inventions (Inventions 1 to 5), it is preferable that the interface ablation layer contains an ultraviolet absorber (Invention 6).

[0015] In the above inventions (Inventions 1 to 6), it is preferable that the interface ablation layer contains a photosensitizer (Invention 7).

[0016] In the above invention (Invention 7), the photosensitizer is preferably a compound having a heterocycle (Invention 8).

[0017] In the above inventions (Inventions 7 and 8), it is preferable that the photosensitizer is at least one of a coumarin-based photosensitizer and a pyrazoline-based photosensitizer (Invention 9).

[0018] In the above inventions (inventions 7 to 9), it is preferable that the content of the photosensitizer in the interfacial ablation layer is 0.1% or more and 10% or less (invention 10).

[0019] In the above inventions (inventions 1 to 10), it is preferable that a blister is formed at the location where the interface ablation occurs when interface ablation is caused in the interface ablation layer (invention 11).

[0020] In the above inventions (inventions 1 to 11), it is preferable that the interface ablation layer is used to selectively separate any workpiece from the interface ablation layer, which is held on the surface of the interface ablation layer opposite to the substrate, by locally generated interface ablation in the interface ablation layer (invention 12).

[0021] Secondly, the present invention provides a device manufacturing method (Invention 13) characterized by comprising: a preparation step of preparing a laminate in which a plurality of workpieces are held on the surface of the interface ablation layer in a work handling sheet (Inventions 1 to 12); a placement step of arranging the laminate on an object capable of receiving the workpieces such that the surfaces of the laminate on which the workpieces are held face to each other; and a separation step of irradiating a laser beam to a position on the interface ablation layer of the laminate where at least one of the workpieces is attached, thereby causing interface ablation at the irradiated position in the interface ablation layer, separating the workpieces located at the position where interface ablation has occurred from the work handling sheet, and placing the workpieces on the object.

[0022] The work handling sheet according to the present invention can handle small workpieces well by suppressing the effects of static electricity, and the device manufacturing method according to the present invention can manufacture devices with excellent performance.

[0023] This is a cross-sectional view of a work handling sheet according to one embodiment of the present invention. This is a cross-sectional view illustrating a method for manufacturing a device using the work handling sheet according to one embodiment of the present invention. This is a cross-sectional view illustrating the state of the blister and reaction area caused by irradiation with laser light.

[0024] Embodiments of the present invention will be described below. Figure 1 shows a cross-sectional view of a work handling sheet according to one embodiment. The work handling sheet 1 shown in Figure 1 comprises a base material 12 and an interface ablation layer 11 laminated on one side of the base material 12.

[0025] In the work handling sheet 1 according to this embodiment, the interface ablation layer 11 is capable of holding workpieces. That is, the work handling sheet 1 according to this embodiment can hold workpieces laminated on the surface of the interface ablation layer 11 opposite to the substrate 12 in that state.

[0026] Although the specific manner of retention described above is not limited, a preferred example is retention by the interfacial ablation layer 11 exhibiting adhesiveness to the workpiece piece. In this case, it is preferable that the interfacial ablation layer 11 contains an adhesive as one of its constituent components, as will be described later, i.e., it is an adhesive layer.

[0027] Furthermore, the interface ablation layer 11 in this embodiment undergoes interface ablation by irradiation with laser light. That is, the interface ablation layer 11 undergoes localized interface ablation in the region irradiated with the laser light. The laser light is not particularly limited as long as it is capable of causing interface ablation, and may have wavelengths in the ultraviolet, visible, or infrared regions, with a laser light having a wavelength in the ultraviolet region being preferred.

[0028] In this specification, interfacial ablation refers to the process in which some of the components constituting the interfacial ablation layer 11 evaporate or volatilize due to the energy of the laser light, and the resulting gas accumulates at the interface between the interfacial ablation layer 11 and the substrate 12, creating a void (blister). In this case, the shape of the interfacial ablation layer 11 changes due to the blister, causing the workpiece fragments to peel off from the interfacial ablation layer 11 and separate.

[0029] Furthermore, in the work handling sheet 1 according to this embodiment, the surface resistivity of the interface ablation layer 11 on the side opposite to the substrate 12 is 1.5 × 10 １３ The static charge is less than or equal to Ω / sq. As a result, the work handling sheet 1 according to this embodiment is less prone to static charge. For example, even when peeling off a release sheet laminated on the interface ablation layer 11, peeling charge is less likely to occur. As a result, the adhesion and re-adhesion of workpiece pieces to the interface ablation layer 11 due to the influence of static electricity is suppressed, enabling good separation of workpiece pieces.

[0030] From the perspective of achieving better antistatic properties, the above surface resistivity is 5.0 × 10１２ is preferably 1.0×10 １２ Ω / sq or less, particularly preferably 1.0×10 ８ Ω / sq or less. There is no particular limitation on the lower limit of the surface resistivity, and for example, it may be 1.0×10 ９ Ω / sq or more, and may particularly be 1.0×10

[0031] In the work handling sheet 1 according to the present embodiment, the surface resistivity on the surface of the base material 12 opposite to the interfacial ablation layer 11 is 1.0×10 １３ Ω / sq or less, particularly preferably 5.0×10 １２ Ω / sq or less, more preferably 1.0×10 １２ Ω / sq or less. Thereby, the work handling sheet 1 according to the present embodiment becomes less likely to be charged, and it becomes easier to more effectively suppress adhesion and re-adhesion of work pieces. The lower limit of the surface resistivity on the surface of the base material 12 opposite to the interfacial ablation layer 11 is, for example, 1.0×10 ８ Ω / sq or more, and may particularly be 5.0×10 ８ Ω / sq or less. Details of the method for measuring the surface resistivity are as described in the test examples described later.

[0032] From the viewpoint of easily achieving the above surface resistivity, the work handling sheet 1 according to the present embodiment preferably contains an antistatic agent. In this case, the antistatic agent may be contained in the interfacial ablation layer 11, may be contained in the base material 12, or may be contained in both of them. Further, the work handling sheet 1 according to the present embodiment may be provided with an antistatic layer containing an antistatic agent.

[0033] 1. Antistatic Layer When the work handling sheet 1 according to the present embodiment includes the antistatic layer described above, the antistatic layer may be provided, for example, between the interfacial ablation layer 11 and the substrate 12, or may be laminated on the surface of the substrate 12 opposite to the interfacial ablation layer 11. Furthermore, the work handling sheet 1 according to the present embodiment may be provided with two antistatic layers, one between the interfacial ablation layer 11 and the substrate 12, and the other on the surface of the substrate 12 opposite to the interfacial ablation layer 11.

[0034] The composition and configuration of the antistatic layer are not particularly limited as long as it contains an antistatic agent and can achieve the above-described surface resistivity. For example, the antistatic layer may be a layer formed of an antistatic layer composition containing a binder resin and an antistatic agent.

[0035] The binder resin preferably contains at least one selected from the group consisting of polyester resins, urethane resins, and acrylic resins as a main component. These resins may be thermosetting compounds or ultraviolet-curable compounds.

[0036] As the antistatic agent, it is preferable to use at least one selected from, for example, conductive polymers, conductive fine particles, ionic compounds, and quaternary ammonium salt-containing compounds.

[0037] As the conductive polymer, conventionally known ones can be used, and among them, polythiophene-based, polyaniline-based, or polypyrrole-based conductive polymers are preferable. One type of conductive polymer may be used alone, or two or more types may be used in combination.

[0038] Examples of polythiophene-based conductive polymers include polythiophene, poly(3-alkylthiophene), poly(3-thiophene-β-ethanesulfonic acid), mixtures of polyalkylenedioxythiophene and polystyrene sulfonate (PSS) (including doped ones), and the like. Among these, mixtures of polyalkylenedioxythiophene and polystyrene sulfonate are preferred. Examples of said polyalkylenedioxythiophene include poly(3,4-ethylenedioxythiophene) (PEDOT), polypropylenedioxythiophene, poly(ethylene / propylene)dioxythiophene, and the like, with poly(3,4-ethylenedioxythiophene) being preferred among them. That is, among the above, a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT doped with PSS) is particularly preferred.

[0039] Examples of polyaniline-based conductive polymers include polyaniline, polymethylaniline, polymethoxyaniline, and the like.

[0040] Examples of polypyrrole-based conductive polymers include polypyrrole, poly 3-methylpyrrole, poly 3-octylpyrrole, and the like.

[0041] Examples of said conductive fine particles include conductive inorganic fine particles such as tin oxide, antimony-doped tin oxide (ATO), indium oxide-tin oxide (ITO), zinc oxide, and antimony pentoxide; fine particles obtained by coating the surfaces of organic fine particles such as silicone fine particles with a conductive compound; and conductive fine particles such as carbon fine particles.

[0042] Said ionic compound may be liquid or solid at room temperature, but from the viewpoint that it easily exhibits stable antistatic properties even when exposed to durability conditions, those that are solid at room temperature are preferred. Here, the ionic compound in the present specification refers to a compound formed by bonding of cations and anions mainly via electrostatic attraction.

[0043] Examples of ionic compounds include nitrogen-containing onium salts, sulfur-containing onium salts, phosphorus-containing onium salts, alkali metal salts, or alkaline earth metal salts. From the viewpoint of the resulting support substrate having excellent durability, nitrogen-containing onium salts or alkali metal salts are particularly preferred, and nitrogen-containing onium salts are even more preferred. Nitrogen-containing onium salts are preferably ionic compounds composed of a nitrogen-containing heterocyclic cation and its counter anion.

[0044] The nitrogen-containing heterocyclic skeleton of the nitrogen-containing heterocyclic cation is preferably a pyridine ring, pyrimidine ring, imidazole ring, triazole ring, indole ring, etc., with the pyridine ring being particularly preferred. The cation of the alkali metal salt is preferably a lithium ion, potassium ion, or sodium ion, with lithium ions or potassium ions being particularly preferred.

[0045] On the other hand, preferred anions constituting the above-mentioned ionic compound are halogenated phosphate anions or sulfonylimide anions. Preferred halogenated phosphate anions include hexafluorophosphate. Preferred sulfonylimide anions include bis(fluoroalkylsulfonyl)imide or bis(fluorosulfonyl)imide.

[0046] Specific examples of the above ionic compounds include pyridinium hexafluorophosphate compounds such as N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N-octylpyridinium hexafluorophosphate, N-octyl-4-methylpyridinium hexafluorophosphate, N-dodecylpyridinium hexafluorophosphate, N-tetradecylpyridinium hexafluorophosphate, N-hexadecylpyridinium hexafluorophosphate, N-hexadecyl-4-methylpyridinium hexafluorophosphate, N-hexadecyl-4-methylpyridinium hexafluorophosphate, and N-hexadecyl-4-methylpyridinium hexafluorophosphate; and N-decylpyridinium. Examples of fluorosulfonylimide compounds include bis(fluorosulfonyl)imide, 1-ethylpyridinium bis(fluorosulfonyl)imide, 1-butylpyridinium bis(fluorosulfonyl)imide, 1-hexylpyridinium bis(fluorosulfonyl)imide, 1-butyl-3-methylpyridinium bis(fluorosulfonyl)imide, 1-butyl-4-methylpyridinium bis(fluorosulfonyl)imide, 1-hexyl-3-methylpyridinium bis(fluorosulfonyl)imide, 1-butyl-3,4-dimethylpyridinium bis(fluorosulfonyl)imide, potassium bis(fluorosulfonyl)imide, lithium bis(fluorosulfonyl)imide, potassium bis(fluoromethanesulfonyl)imide, and lithium bis(fluoromethanesulfonyl)imide. These ionic compounds may be used individually or in combination of two or more.

[0047] Examples of the above-mentioned quaternary ammonium salt-containing compounds include pyrrolidium rings, quaternary compounds of alkylamines, copolymers thereof with acrylic acid or methacrylic acid, quaternary compounds of N-alkylaminoacrylamide, vinylbenzyltrimethylammonium salt, and 2-hydroxy-3-methacrylateoxypropyltrimethylammonium salt.

[0048] From the viewpoint of easily achieving excellent antistatic properties, the content of the antistatic agent in the antistatic layer is preferably 0.1% by mass or more, particularly preferably 1% by mass or more, and even more preferably 3% by mass or more. On the other hand, from the viewpoint of easily forming the desired antistatic layer, the above content is preferably 80% by mass or less, particularly preferably 60% by mass or less, and even more preferably 40% by mass or less.

[0049] The antistatic layer composition may also contain, in addition to the above-mentioned components, crosslinking agents, leveling agents, antifouling agents, etc.

[0050] The thickness of the antistatic layer is preferably 10 nm or more, and particularly preferably 30 nm or more, from the viewpoint of making it easier to achieve excellent antistatic properties. Furthermore, the thickness of the antistatic layer is preferably 10 μm or less, and particularly preferably 3 μm or less, from the viewpoint of improving the handling properties of the work handling sheet 1.

[0051] 2. Interface Ablation Layer The specific configuration and composition of the interface ablation layer 11 in this embodiment are not particularly limited, as long as it is capable of holding workpiece pieces and has the property of undergoing interface ablation by irradiation with laser light.

[0052] In this embodiment, the interfacial ablation layer 11 is preferably an adhesive layer, as described above. The adhesive constituting the adhesive layer may be any of the following: acrylic adhesive, rubber adhesive, silicone adhesive, urethane adhesive, polyester adhesive, polyvinyl ether adhesive, etc. However, from the viewpoint of easily exhibiting the desired adhesive strength, an acrylic adhesive is preferred. In this case, if the interfacial ablation layer 11 is composed of an acrylic adhesive, it is preferable that the interfacial ablation layer 11 is formed from an adhesive composition containing the above-mentioned photosensitizer and acrylic polymer.

[0053] (1) Acrylic polymer The acrylic polymer is not particularly limited as long as the interfacial ablation layer 11 (adhesive layer) is able to exhibit a predetermined level of tackiness. For example, the acrylic polymer preferably contains structural units derived from functional group-containing monomers and structural units derived from (meth)acrylic acid ester monomers or their derivatives.

[0054] The above-mentioned functional group-containing monomer is preferably a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, carboxyl group, amino group, substituted amino group, or epoxy group within its molecule.

[0055] Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, which can be used individually or in combination of two or more.

[0056] Examples of carboxyl group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used individually or in combination of two or more.

[0057] Examples of amino group-containing monomers or substituted amino group-containing monomers include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used individually or in combination of two or more.

[0058] As the above (meth)acrylic acid ester monomers, in addition to alkyl (meth)acrylates having 1 to 20 carbon atoms in the alkyl group, monomers having an alicyclic structure in the molecule (alicyclic structure-containing monomers) are preferably used.

[0059] As alkyl (meth)acrylates, alkyl (meth)acrylates in which the alkyl group has 1 to 18 carbon atoms are particularly preferred, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. These may be used individually or in combination of two or more.

[0060] Preferred monomers containing an alicyclic structure include, for example, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. These may be used individually or in combination of two or more.

[0061] The acrylic polymer contains structural units derived from the above-mentioned functional group-containing monomer in a proportion preferably of 1% by mass or more, particularly preferably of 5% by mass or more, and even more preferably of 10% by mass or more. Alternatively, the acrylic polymer may contain structural units derived from the above-mentioned functional group-containing monomer in a proportion preferably of 35% by mass or less, particularly preferably of 30% by mass or less, and even more preferably of 25% by mass or less.

[0062] Furthermore, the acrylic polymer contains structural units derived from (meth)acrylic acid monomers or their derivatives in a proportion preferably of 50% by mass or more, particularly preferably of 60% by mass or more, and even more preferably of 70% by mass or more. In addition, the acrylic polymer contains structural units derived from (meth)acrylic acid monomers or their derivatives in a proportion preferably of 99% by mass or less, particularly preferably of 95% by mass or less, and even more preferably of 90% by mass or less.

[0063] Acrylic polymers can be obtained by copolymerizing functional group-containing monomers as described above with (meth)acrylic acid ester monomers or their derivatives using conventional methods. However, in addition to these monomers, dimethylacrylamide, vinyl formate, vinyl acetate, styrene, and the like may also be copolymerized.

[0064] The weight-average molecular weight (Mw) of the acrylic polymer obtained in this manner is preferably 10,000 or more, particularly preferably 100,000 or more, and even more preferably 150,000 or more. Furthermore, the weight-average molecular weight (Mw) is preferably 1,500,000 or less, particularly preferably 1,250,000 or less, and even more preferably 1,000,000 or less. In this specification, the weight-average molecular weight (Mw) is a value on a standard polystyrene basis measured by gel permeation chromatography (GPC).

[0065] Furthermore, the acrylic polymer in this embodiment may be one in which a functional group having active energy ray curability (active energy ray curable group) is introduced into the side chain by reacting an unsaturated group-containing compound with a functional group derived from the functional group-containing monomer unit described above.

[0066] The functional group of the unsaturated group-containing compound can be appropriately selected depending on the type of functional group of the functional group-containing monomer unit of the acrylic polymer. For example, if the functional group of the acrylic polymer is a hydroxyl group, an amino group, or a substituted amino group, the functional group of the unsaturated group-containing compound is preferably an isocyanate group or an epoxy group. If the functional group of the acrylic polymer is an epoxy group, the functional group of the unsaturated group-containing compound is preferably an amino group, a carboxyl group, or an aziridinyl group.

[0067] Furthermore, the above-mentioned unsaturated group-containing compound contains at least one, preferably 1 to 6, and more preferably 1 to 4, energy-ray polymerizable carbon-carbon double bonds per molecule. Specific examples of such unsaturated group-containing compounds include, for example, 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate; acryloyl monoisocyanate compounds obtained by the reaction of a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth)acrylate; acryloyl monoisocyanate compounds obtained by the reaction of a diisocyanate compound or polyisocyanate compound with a polyol compound with hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, and the like.

[0068] The above unsaturated group-containing compound is used in a ratio of preferably 50 mol% or more, particularly preferably 60 mol% or more, and even more preferably 70 mol% or more, relative to the number of moles of the functional group-containing monomer of the above acrylic polymer. Furthermore, the above unsaturated group-containing compound is used in a ratio of preferably 95 mol% or less, particularly preferably 93 mol% or less, and even more preferably 90 mol% or less, relative to the number of moles of the functional group-containing monomer of the above acrylic polymer.

[0069] In the reaction between an acrylic polymer and an unsaturated group-containing compound, the reaction temperature, pressure, solvent, time, presence or absence of a catalyst, and type of catalyst can be appropriately selected depending on the combination of functional groups present in the acrylic polymer and the unsaturated group-containing compound. As a result, the functional groups present in the acrylic polymer react with the functional groups in the unsaturated group-containing compound, and the unsaturated groups are introduced into the side chains of the acrylic polymer.

[0070] In this embodiment, the acrylic polymer may be one in which an active energy ray curable group is introduced, or it may be one in which an active energy ray curable group is introduced. An acrylic polymer in which an active energy ray curable group is introduced can be obtained, for example, by reacting an acrylic copolymer having the above-mentioned functional group-containing monomer units with an unsaturated group-containing compound having a functional group that is bonded to the functional group.

[0071] (2) Crosslinking agent The adhesive composition described above may also preferably contain a crosslinking agent. Using a crosslinking agent makes it easier to adjust the storage modulus of the interfacial ablation layer 11 to a desired range. As the crosslinking agent, a polyfunctional compound that has reactivity with functional groups of acrylic polymers, etc., can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, reactive phenolic resins, etc.

[0072] Isocyanate-based crosslinking agents include at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; and their biuret and isocyanurate forms, as well as adducts which are reaction products with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil.

[0073] Among these, trimethylolpropane-modified aromatic polyisocyanates, particularly trimethylolpropane-modified xylylene diisocyanate and trimethylolpropane-modified hexamethylene diisocyanate, are preferred from the viewpoint of excellent antistatic properties, with trimethylolpropane-modified hexamethylene diisocyanate being particularly preferred. Although the details are unclear, it is thought that differences in the crosslinking structure also affect the conductivity of the entire interface ablation layer.

[0074] The amount of crosslinking agent in the adhesive composition is preferably 0.001 parts by mass or more, particularly preferably 0.1 parts by mass or more, and even more preferably 0.2 parts by mass or more, per 100 parts by mass of the acrylic polymer. Furthermore, the amount of crosslinking agent is preferably 30 parts by mass or less, particularly preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the acrylic polymer, from the viewpoint of antistatic properties.

[0075] (3) Antistatic agent As described above, the interfacial ablation layer 11 may contain an antistatic agent. In that case, it is preferable to include the antistatic agent in the adhesive composition described above. Examples of antistatic agents that can be used here include those described above.

[0076] When the adhesive composition contains an antistatic agent, the amount of the antistatic agent is preferably 0.1 parts by mass or more, particularly preferably 1 part by mass or more, and more preferably 2 parts by mass or more, per 100 parts by mass of the acrylic polymer. Furthermore, the amount of the antistatic agent is preferably 20 parts by mass or less, particularly preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the acrylic polymer.

[0077] (4) The UV absorber interface ablation layer 11 may also preferably contain a UV absorber. The presence of a UV absorber in the interface ablation layer 11 improves the efficiency of the interface ablation layer 11 in receiving energy from the laser light.

[0078] The type of UV absorber in this embodiment is not particularly limited. The UV absorber in this embodiment may be an organic compound or an inorganic compound, but an organic compound is preferred from the viewpoint of easily generating good interfacial ablation.

[0079] When the UV absorber is an organic compound, preferred examples of such UV absorbers include hydroxyphenyltriazine-based UV absorbers, benzophenone-based UV absorbers, benzotriazole-based UV absorbers, benzoate-based UV absorbers, benzoxazinon-based UV absorbers, phenylsalicylate-based UV absorbers, cyanoacrylate-based UV absorbers, nickel complex salt-based UV absorbers, hydroquinone-based UV absorbers, salicylic acid-based UV absorbers, malonic acid ester-based UV absorbers, and oxalic acid-based UV absorbers. These may be used individually or in combination of two or more.

[0080] Among the UV absorbers mentioned above, it is preferable to use at least one of the following: a hydroxyphenyltriazine-based UV absorber, a benzophenone-based UV absorber, and a benzotriazole-based UV absorber, from the viewpoint of having good absorption at the third harmonic of YAG (355 nm) and readily producing good interfacial ablation. In particular, it is preferable to use a hydroxyphenyltriazine-based UV absorber.

[0081] When the adhesive composition contains an ultraviolet absorber, the amount of the ultraviolet absorber is preferably 1 part by mass or more, more preferably 2 parts by mass or more, particularly preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the acrylic polymer. Furthermore, the amount of the ultraviolet absorber is preferably 75 parts by mass or less, more preferably 60 parts by mass or less, particularly preferably 50 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the acrylic polymer.

[0082] (5) The photosensitizer interface ablation layer 11 may also preferably contain a photosensitizer. The presence of a photosensitizer in the interface ablation layer 11 makes it easier for the interface ablation layer 11 to efficiently receive energy from the laser light. As a result, interface ablation occurs effectively, making it easier to separate the held workpiece pieces from the interface ablation layer 11. In particular, even under conditions where separation was difficult with conventional work handling sheets, from the viewpoint of the size and thickness of the workpiece pieces to be separated, and from the viewpoint of the laser light irradiation method, the work handling sheet 1 according to this embodiment makes it possible to separate the workpiece pieces well.

[0083] The photosensitizer in this embodiment is not particularly limited. From the viewpoint of more effectively inducing interfacial ablation, it is preferable to use a photosensitizer that satisfies the condition that the absorbance of light at a wavelength of 365 nm, measured from a solution obtained by dissolving the photosensitizer in an organic solvent at a concentration of 10 ppm, is 0.3 or higher.

[0084] From the viewpoint of improving the efficiency of receiving energy from laser light, the absorbance of the photosensitizer in this embodiment is more preferably 0.4 or higher, particularly preferably 0.5 or higher, and even more preferably 0.8 or higher. The organic solvent used when measuring the absorbance is selected for each photosensitizer, taking into consideration the solubility of the photosensitizer. The effect of differences in organic solvents on the measured absorbance is very small. The absorbance described above was obtained by dissolving the photosensitizer in an organic solvent to prepare a 10 ppm solution, measuring the absorption spectrum at wavelengths of 200 to 800 nm using a spectrophotometer, and reading the absorbance at 365 nm.

[0085] Furthermore, the photosensitizer in this embodiment is preferably a compound having a heterocycle, from the viewpoint of more effectively inducing interfacial ablation. The number of heterocycles in the compound may be one or two or more. In addition, the compound may have a carbocyclic ring in addition to the heterocycle.

[0086] The above heterocycle preferably contains at least one element other than carbon selected from nitrogen, oxygen, phosphorus, sulfur, silicon, and selenium, and is particularly preferably contained at least one element selected from nitrogen, oxygen, phosphorus, and sulfur.

[0087] Furthermore, there is no particular limit to the number of atoms constituting the ring structure of the heterocycle described above; for example, it may be 3 or more and 9 or less, and it is particularly preferable that it be 5 or more and 6 or less.

[0088] In this embodiment, the photosensitizer is preferably at least one of a coumarin-based photosensitizer having a coumarin skeleton and a pyrazoline-based photosensitizer having a pyrazoline skeleton, from the viewpoint of facilitating better interfacial ablation.

[0089] The content of the photosensitizer in the interfacial ablation layer 11 is preferably 0.1% or more, particularly preferably 0.5% or more, and even more preferably 0.9% or more. Furthermore, the content is preferably 10% or less, particularly preferably 8% or less, and even more preferably 6% or less. Having the photosensitizer content within these ranges facilitates efficient interfacial ablation.

[0090] As mentioned above, the interfacial ablation layer 11 may contain an ultraviolet absorber. However, if the interfacial ablation layer 11 contains a photosensitizer, depending on the type and amount of the photosensitizer, it may be easier to produce good interfacial ablation if the interfacial ablation layer 11 does not contain an ultraviolet absorber or contains only a very small amount. Therefore, when the interfacial ablation layer 11 contains both a photosensitizer and an ultraviolet absorber, the amount of ultraviolet absorber in the interfacial ablation layer 11 is preferably less than 10%, particularly preferably 5% or less, and even more preferably 1% or less. Furthermore, when the interfacial ablation layer 11 contains both a photosensitizer and an ultraviolet absorber, if the interfacial ablation layer 11 contains an ultraviolet absorber, its content is preferably 0.1% or more.

[0091] (6) Other components The interface ablation layer 11 may appropriately contain other components other than those described above. Examples of other components include photopolymerization initiators.

[0092] (7) Thickness of the interface ablation layer In this embodiment, the thickness of the interface ablation layer 11 is preferably 3 μm or more, particularly preferably 20 μm or more, and even more preferably 25 μm or more. Furthermore, the thickness of the interface ablation layer 11 is preferably 100 μm or less, particularly preferably 50 μm or less, and even more preferably 40 μm or less. Having the thickness of the interface ablation layer 11 within the above range makes it easier to achieve both the retention of the workpiece on the interface ablation layer 11 and the separation of the workpiece by interface ablation.

[0093] 3. Base Material The base material 12 in this embodiment is not particularly limited in terms of its composition or physical properties. From the viewpoint of making it easier for the work handling sheet 1 to perform the desired function, it is preferable that the base material 12 be made of a resin. When the base material 12 is made of a resin, examples of the resin include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin resins such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymer, and norbornene resin; ethylene-vinyl acetate copolymer; ethylene copolymer resins such as ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer, and other ethylene-(meth)acrylic acid ester copolymers; polyvinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymer; (meth)acrylic acid ester copolymer; polyurethane; polyimide; polystyrene; polycarbonate; and fluororesin. Furthermore, the resin constituting the base material 12 may be a crosslinked version of the above-mentioned resins or a modified version such as an ionomer of the above-mentioned resins. Furthermore, the base material 12 may be a single-layer film made of the resin described above, or it may be a laminated film formed by laminating multiple such films. In this laminated film, the materials constituting each layer may be of the same type or different types.

[0094] As mentioned above, the base material 12 may contain an antistatic agent. Examples of antistatic agents that can be used here include those mentioned above. When the base material 12 contains an antistatic agent, the amount of antistatic agent in the base material 12 is preferably 0.1% by mass or more, particularly preferably 1% by mass or more, and even more preferably 2% by mass or more. Furthermore, the above amount is preferably 80% by mass or less, particularly preferably 60% by mass or less, and even more preferably 40% by mass or less.

[0095] In this embodiment, the substrate 12 may contain various additives such as colorants, flame retardants, plasticizers, antistatic agents, lubricants, and fillers. Furthermore, if the interfacial ablation layer 11 contains a material that hardens with active energy rays, it is preferable that the substrate 12 is permeable to active energy rays.

[0096] The method for manufacturing the base material 12 in this embodiment is not particularly limited as long as it is manufactured from a resin. For example, it can be manufactured by forming the resin into a sheet using a melt extrusion method such as a T-die method or a circular die method; a calendering method; a solution method such as a dry method or a wet method.

[0097] In this embodiment, the surface of the substrate 12 may be subjected to surface treatment such as oxidation or embossing, or primer treatment, in order to improve adhesion to the interfacial ablation layer 11. Examples of oxidation methods include corona discharge treatment, plasma discharge treatment, chromium oxidation (wet), flame treatment, hot air treatment, ozone, and ultraviolet irradiation treatment. Examples of embossing methods include sandblasting and thermal spraying.

[0098] In this embodiment, the thickness of the base material 12 is preferably 10 μm or more, and particularly preferably 30 μm or more. Furthermore, the thickness of the base material 12 is preferably 500 μm or less, more preferably 300 μm or less, particularly preferably 200 μm or less, even more preferably 150 μm or less, and most preferably 100 μm or less. When the thickness of the base material 12 is within the above range, the work handling sheet 1 will have a predetermined balance of rigidity and flexibility, making it easier to handle small workpieces well.

[0099] 4. Release Sheet If the interface ablation layer 11 in this embodiment includes an adhesive as one of its constituent components, a release sheet may be laminated on the surface of the interface ablation layer 11 opposite to the substrate 12 for the purpose of protecting that surface until it is attached to the workpiece.

[0100] The composition of the release sheet described above is arbitrary, and an example is a plastic film that has been treated with a release agent. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, silicone-based, fluorine-based, and long-chain alkyl-based agents can be used, and among these, silicone-based agents are preferred because they are inexpensive and provide stable performance.

[0101] There are no particular restrictions on the thickness of the release sheet mentioned above; for example, it may be between 20 μm and 250 μm.

[0102] 5. Other Configurations In the work handling sheet 1 according to this embodiment, an adhesive layer may be laminated on the side of the interface ablation layer 11 opposite to the substrate 12. In this sheet, a workpiece can be attached to the side of the adhesive layer opposite to the interface ablation layer 11, and by dicing the adhesive layer together with the workpiece, a workpiece piece can be obtained in which individual pieces of the adhesive layer are laminated. The chip can be easily fixed to the object on which the workpiece piece is mounted by these individual pieces of adhesive layer. It is preferable to use a material that contains a thermoplastic resin and a low molecular weight thermosetting adhesive component, or a material that contains a B-stage (semi-cured) thermosetting adhesive component, etc., as the material constituting the adhesive layer described above.

[0103] Furthermore, in the work handling sheet 1 according to this embodiment, a protective film forming layer may be laminated on the side of the interface ablation layer 11 opposite to the substrate 12. In such a sheet, a workpiece can be attached to the side of the protective film forming layer opposite to the interface ablation layer 11, and the protective film forming layer can be diced together with the workpiece to obtain workpiece pieces with laminated individual protective film forming layers. Preferably, a workpiece with a circuit formed on one side is used, and in this case, the protective film forming layer is usually laminated on the side opposite to the side with the circuit. By curing the individual protective film forming layers at a predetermined timing, a protective film with sufficient durability can be formed on the workpiece pieces. Preferably, the protective film forming layer is made of an uncured curable adhesive.

[0104] 6. Method for Manufacturing the Work Handling Sheet The method for manufacturing the work handling sheet 1 according to this embodiment is not particularly limited. For example, the interface ablation layer 11 may be directly formed on the substrate 12, or the interface ablation layer 11 may be formed on a process sheet and then transferred onto the substrate 12.

[0105] If the interfacial ablation layer 11 contains an adhesive as one of its constituent components, the interfacial ablation layer 11 can be formed by a known method. For example, a coating solution containing an adhesive composition for forming the interfacial ablation layer 11, and optionally a solvent or dispersion medium, can be prepared. Then, the coating solution can be applied to one side of the substrate or the peelable side of the release sheet (hereinafter sometimes referred to as the "release surface"). Subsequently, the resulting coating film can be dried to form the interfacial ablation layer 11.

[0106] The coating solution described above can be applied by known methods, such as bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, roll knife coating, etc. The properties of the coating solution are not particularly limited as long as it can be applied, and it may contain components for forming the interface ablation layer 11 as a solute or as a dispersed phase. Furthermore, if the interface ablation layer 11 is formed on a release sheet, the release sheet may be peeled off as a process material, or it may protect the interface ablation layer 11 until it is attached to the adherend.

[0107] If the adhesive composition for forming the interfacial ablation layer 11 contains the aforementioned crosslinking agent, it is preferable to promote the crosslinking reaction between the polymer component in the coating film and the crosslinking agent by changing the drying conditions (temperature, time, etc.) or by separately performing a heat treatment, thereby forming a crosslinked structure with a desired density within the interfacial ablation layer 11. Furthermore, in order to allow the above-mentioned crosslinking reaction to proceed sufficiently, curing may be performed after the completion of the work handling sheet 1, for example, by leaving it undisturbed in an environment of 23°C and 50% relative humidity for several days.

[0108] If the work handling sheet 1 according to this embodiment is equipped with an antistatic layer, the antistatic layer can be formed by preparing the aforementioned antistatic layer composition, applying it to the substrate 12, and drying the resulting coating film. The antistatic layer composition may be diluted with a solvent as appropriate.

[0109] 7. Method of Using the Work Handling Sheet The work handling sheet 1 according to this embodiment can be suitably used for handling small workpieces. As described above, in the work handling sheet 1 according to this embodiment, the interface ablation layer 11 is efficiently subjected to interface ablation by irradiation with laser light, so that small workpieces held on the interface ablation layer 11 can be separated to predetermined positions with high precision.

[0110] One example of how to use the work handling sheet 1 according to this embodiment is to selectively separate any work piece from the interface ablation layer 11 by locally generated interface ablation in the interface ablation layer 11, which is held on the surface of the interface ablation layer 11 opposite to the substrate 12.

[0111] In the above method of use, the multiple workpiece pieces held on the interface ablation layer 11 may be obtained by dicing a workpiece (the material for the workpiece pieces) held on the surface of the interface ablation layer 11 opposite to the substrate 12 on that surface. That is, the workpiece pieces may be obtained by dicing a workpiece on the interface ablation layer 11. Alternatively, the workpiece pieces may be formed independently of the workpiece handling sheet 1 according to this embodiment and placed on the interface ablation layer 11.

[0112] Furthermore, if the work handling sheet 1 according to this embodiment includes the aforementioned adhesive layer and protective film forming layer, it is preferable to dic these layers and the workpiece on the interface ablation layer 11. This makes it possible to obtain workpiece pieces in which these layers are individually separated and laminated.

[0113] While the shape and size of the workpiece pieces in this embodiment are not particularly limited, regarding the size, if the workpiece piece is rectangular, the minimum side length is preferably 0.2 mm or more, and more preferably 0.3 mm or more. Furthermore, the minimum side length is preferably 50 mm or less, more preferably 20 mm or less, and even more preferably 10 mm or less. On the other hand, the area is 0.04 mm². ２ The following (for example, 10 μm) ２ ~0.04 mm ２) and materials with a thickness of 1 to 10,000 μm (for example, 5 to 500 μm) can also be handled well. The work handling sheet according to this embodiment can handle workpieces of various sizes and thicknesses well.

[0114] Examples of workpiece pieces include semiconductor components and semiconductor devices, and more specifically, micro light-emitting diodes, power devices, and MEMS (Micro Electro Mechanical Systems). Among these, the workpiece piece is preferably a light-emitting diode, and in particular, it is preferably a light-emitting diode selected from mini light-emitting diodes and micro light-emitting diodes. In recent years, the development of devices in which mini light-emitting diodes and micro light-emitting diodes are arranged at high density has been considered, and in the manufacture of such devices, the workpiece handling sheet 1 according to this embodiment, which can handle these light-emitting diodes with high precision, is very suitable.

[0115] Below, a device manufacturing method will be described below as a specific example of the use of work handling sheet 1, based on Figure 2. This device manufacturing method comprises at least three steps: a preparation step (Figure 2(a)), a placement step (Figure 2(b)), and a separation step (Figures 2(c) and (d)).

[0116] In the preparation step, as shown in Figure 2(a), a laminate is prepared in which a plurality of workpiece pieces 2 are held on the surface of the work handling sheet 1 according to this embodiment, on the side facing the interface ablation layer 11. This laminate may be prepared by placing separately prepared workpiece pieces 2 on the work handling sheet 1, or by dicing the workpieces held on the surface facing the interface ablation layer 11. This dicing can be carried out by known methods.

[0117] As mentioned above, there are no particular limitations on the shape or size of the workpiece 2, and the preferred size is also as mentioned above. Specific examples of the workpiece 2 include semiconductor components and semiconductor devices, as mentioned above, and in particular, light-emitting diodes such as mini light-emitting diodes and micro light-emitting diodes.

[0118] In the subsequent arrangement step, as shown in Figure 2(b), the laminate is positioned so that the side of the laminate facing the workpiece 2 is facing the object 3 capable of receiving the workpiece 2. The object 3 is appropriately determined depending on the device to be manufactured, but when the workpiece 2 is a light-emitting diode, specific examples of the object 3 include substrates, sheets, reels, etc., and a wiring board with wiring is particularly preferred.

[0119] Subsequently, in the separation process, as shown in Figure 2(c), laser light 4 is first irradiated onto the position where at least one workpiece 2 is attached in the interface ablation layer 11. This irradiation may be performed simultaneously on multiple positions where workpiece 2 is attached, or it may be performed sequentially on those positions. The irradiation conditions for the laser light 4 are not limited as long as they are capable of causing interface ablation. Known laser irradiation devices can be used for irradiation.

[0120] As shown in Figure 2(d), irradiation with the laser light 4 described above can cause interfacial ablation at the irradiated location in the interfacial ablation layer 11. Specifically, irradiation with the laser light 4 causes the components constituting the region of the hardened interfacial ablation layer 11 proximal to the substrate 12 to evaporate or volatilize, forming a reaction region 13. The gas generated by the evaporation or volatilization then accumulates between the substrate 12 and the reaction region 13, forming a blister 5. The formation of the blister 5 causes the interfacial ablation layer 11 to deform locally at the location of the workpiece 2', causing the workpiece 2' to separate as if peeled off from the interfacial ablation layer 11. As a result, the workpiece 2' located at the location where the interfacial ablation occurred can be placed on the object 3.

[0121] The reaction region 13 and blister 5 generated by the irradiation of the laser light 4 usually remain even after the separation of the workpiece 2'. Figure 3 shows the process of separating the workpiece 2 by sequentially irradiating it with laser light, and in particular, the state after separation (the two on the left), the state during separation (center), and the state before separation (the two on the right) are shown. As shown in the figure, the blister 5 after separation is usually somewhat deflated compared to the blister 5 during separation.

[0122] The device manufacturing method described above may include steps other than the preparation step, placement step, and separation step. For example, grinding, die bonding, wire bonding, molding, inspection, transfer, etc., may be performed at any timing between the preparation step and the separation step. Furthermore, if the acrylic polymer has active energy ray curable groups introduced into it, or if the interface ablation layer contains monomers and / or oligomers having active energy ray curable groups, a curing step may be performed between the placement step and the separation step to cure the interface ablation layer, either entirely or locally, by irradiating the entire interface ablation layer in the laminate with active energy rays, or the position on the interface ablation layer in the laminate where at least one workpiece is attached. In this case, the irradiation with active energy rays may be performed using known methods, for example, an ultraviolet irradiation device equipped with a high-pressure mercury lamp or an ultraviolet LED as a light source, or a laser light irradiation device also used in the separation step described later may be used.

[0123] According to the device manufacturing method described above, various devices can be manufactured by appropriately selecting the workpiece 2 and target object 3 to be used. For example, if a light-emitting diode selected from mini light-emitting diodes and micro light-emitting diodes is used as the workpiece 2, a light-emitting device equipped with multiple such light-emitting diodes can be manufactured, and more specifically, a display can be manufactured. In particular, a display equipped with micro light-emitting diodes as pixels, or a display equipped with multiple mini light-emitting diodes as a backlight can be manufactured.

[0124] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Accordingly, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0125] For example, other layers may be provided between the substrate and the interfacial ablation layer, or on the surface of the substrate opposite to the interfacial ablation layer.

[0126] A specific example of the above-mentioned other layers is an adhesive layer. In this case, the separation process described above can be performed with the side with the adhesive layer attached to a support base (a transparent substrate such as a glass plate). The adhesive constituting the adhesive layer is not particularly limited, but it is preferable that it does not easily absorb or block active energy rays. In this case, when laser light is irradiated through the adhesive layer, the laser light can easily reach the interface ablation layer, making it easier to produce good interface ablation. Specifically, it is preferable to use an adhesive that does not have active energy ray curability as the adhesive constituting the adhesive layer, and it is particularly preferable to use an adhesive that does not contain active energy ray curability components. By using an adhesive that does not have active energy ray curability, the adhesive layer will not harden even when irradiated with the above-mentioned laser light, thereby preventing unintended peeling of the work handling sheet from the transparent substrate. The adhesive layer may also contain an antistatic agent. By including an antistatic agent, the above-mentioned antistatic properties can be more easily achieved. The thickness of the adhesive layer is not particularly limited, but is preferably, for example, 5 to 50 μm.

[0127] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0128] [Example 1-1] (1) Formation of an antistatic layer A mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PSS-doped PEDOT) as an antistatic agent, a polyester resin as a binder resin, a crosslinking agent, and a leveling agent were mixed to prepare a coating liquid for forming an antistatic layer.

[0129] The obtained coating solution was applied to one side of a polyolefin film (thickness: 80 μm) used as a substrate, and the resulting coating film was dried. This resulted in a laminate in which a 50 nm thick antistatic layer was laminated on one side of the substrate.

[0130] (2) Preparation of an adhesive composition for forming an interfacial ablation layer 80 parts by mass of 2-ethylhexyl acrylate and 20 parts by mass of 2-hydroxyethyl acrylate were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer. This (meth)acrylic acid ester polymer was reacted with 80 mol% of methacryloyloxyethyl isocyanate (MOI) relative to the 2-hydroxyethyl acrylate to obtain an acrylic polymer (active energy ray curable component) in which active energy ray curable groups were introduced into the side chains. The weight-average molecular weight (Mw) of this acrylic polymer was measured by the method described later and was found to be 1 million.

[0131] 100 parts by mass (based on solid content, the same applies hereinafter) of an acrylic polymer in which active energy ray curable groups have been introduced into the side chains, obtained above, 20 parts by mass of trimethylolpropane-modified xylylene diisocyanate (manufactured by Mitsui Chemicals, product name "Takenate D-110N") as a crosslinking agent, and 10 parts by mass of tris[2,4,6-[2-{4-(octyl-2-methylethanol)oxy-2-hydroxyphenyl}]-1,3,5-triazine (hydroxyphenyltriazine-based ultraviolet absorber, manufactured by BASF, product name "Tinuvin 477") as an ultraviolet absorber were mixed in a solvent to obtain a coating solution for an adhesive composition for forming an interfacial ablation layer.

[0132] (3) Preparation of adhesive composition for forming adhesive layer 90 parts by mass of n-butyl acrylate and 10 parts by mass of acrylic acid were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer. The weight-average molecular weight (Mw) of this acrylic polymer was measured by the method described later and was found to be 600,000.

[0133] 100 parts by mass of the obtained (meth)acrylic acid ester polymer, 3 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Mitsui Chemicals, product name "Takenate D-101E") as a crosslinking agent, and 0.5 parts by mass of an ionic compound (manufactured by Nippon Emulsifier Co., Ltd., product name "Aminoion AS100") as an antistatic agent were mixed in a solvent to obtain a coating solution for an adhesive composition for forming an adhesive layer.

[0134] (4) Formation of the interfacial ablation layer A silicone-based release agent layer was formed on one side of a polyethylene terephthalate film with a thickness of 38 μm (Lintec Corporation, product name "SP-PET381031"), and the adhesive composition coating liquid obtained in step (2) above was applied to the release surface of the release sheet, and the resulting coating film was dried by heating. As a result, a laminate was obtained in which the dried coating film formed an interfacial ablation layer with a thickness of 30 μm and the release sheet (hereinafter referred to as the "first release sheet") were laminated together.

[0135] (5) Formation of adhesive layer A silicone-based release agent layer was formed on one side of a polyethylene terephthalate film with a thickness of 38 μm (Lintec Corporation, product name "SP-PET381031") and the adhesive composition coating liquid obtained in step (3) above was applied to the release surface of the release sheet and the resulting coating film was dried by heating. As a result, a laminate was obtained in which a 10 μm thick adhesive layer formed by the drying of the coating film and the release sheet (hereinafter referred to as the "second release sheet") were laminated together.

[0136] (6) Preparation of work handling sheet By bonding the antistatic layer side of the laminate obtained in step (1) above with the interface ablation layer side of the laminate obtained in step (4) above, a laminate is obtained in which the first release sheet, interface ablation layer, antistatic layer, and substrate are laminated in order.

[0137] Furthermore, by bonding the substrate-side surface of the obtained laminate to the adhesive layer-side surface of the laminate obtained in step (5) above, a work handling sheet was obtained in which a first release sheet, an interfacial ablation layer, an antistatic layer, a substrate, an adhesive layer, and a second release sheet were laminated in that order.

[0138] (7) Gel Permeation Chromatography Method Here, the weight-average molecular weight (Mw) mentioned above is the weight-average molecular weight on a standard polystyrene basis, measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement). <Measurement Conditions> ・Measurement device: HLC-8320, manufactured by Tosoh Corporation ・GPC column (passed in the following order): TSK gel superH-H, TSK gel superHM-H, TSK gel superH2000, manufactured by Tosoh Corporation ・Measurement solvent: Tetrahydrofuran ・Measurement temperature: 40°C

[0139] [Examples 1-2 to 1-10] Work handling sheets were obtained in the same manner as in Example 1-1, except that the type of substrate, the thickness of the substrate, the type and content of the crosslinking agent used in the adhesive composition for forming the interfacial ablation layer, and the content of the ultraviolet absorber were changed as shown in Table 1.

[0140] [Examples 1-11, 1-12] Work handling sheets were obtained in the same manner as in Example 1-1, except that the type of substrate, the thickness of the substrate, the type and content of the crosslinking agent used in the adhesive composition for forming the interfacial ablation layer were changed as shown in Table 1, and the laminate obtained in step (5) was not laminated. The work handling sheet has a structure in which a first release sheet, an interfacial ablation layer, an antistatic layer, and a substrate are laminated in order.

[0141] [Comparative Example 1-1] A work handling sheet was obtained in the same manner as in Example 1-1, except that the type of substrate was changed as shown in Table 1 and an antistatic layer was not formed.

[0142] [Comparative Example 1-2] A work handling sheet was obtained in the same manner as in Example 1-1, except that the type of base material, the content of the crosslinking agent, and the content of the ultraviolet absorber were changed as shown in Table 1, and an antistatic layer was not formed.

[0143] [Example 2-1] (1) Formation of an antistatic layer A mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PSS-doped PEDOT) as an antistatic agent, a polyester resin as a binder resin, a crosslinking agent, and a leveling agent were mixed to prepare a coating liquid for forming an antistatic layer.

[0144] The obtained coating solution was applied to one side of a polyethylene terephthalate film (thickness: 38 μm) used as a substrate, and the resulting coating film was dried. This resulted in a laminate in which a 50 nm thick antistatic layer was laminated on one side of the substrate.

[0145] (2) Preparation of an adhesive composition for forming an interfacial ablation layer 60 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of acryloylmorpholine, and 30 parts by mass of 2-hydroxyethyl acrylate were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer. This (meth)acrylic acid ester polymer was reacted with 90 mol% of methacryloyloxyethyl isocyanate (MOI) relative to the 2-hydroxyethyl acrylate to obtain an acrylic polymer (active energy ray curable component) in which active energy ray curable groups were introduced into the side chains. The weight-average molecular weight (Mw) of this acrylic polymer was measured by the method described above and was found to be 1 million.

[0146] 100 parts by mass (based on solid content, the same applies hereinafter) of an acrylic polymer in which active energy ray curable groups have been introduced into the side chains, 2 parts by mass of hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate HL") as a crosslinking agent, and 3 parts by mass of "NF-CO01" (coumarin-based photosensitizer, absorbance at 365 nm of a 10 ppm dimethylformamide solution (measured with a spectrophotometer): 0.97) manufactured by Nippon Chemical Industries, Ltd., as a photosensitizer were mixed in a solvent to obtain a coating solution for forming an interfacial ablation layer.

[0147] (3) Preparation of an adhesive composition for forming an adhesive layer 90 parts by mass of n-butyl acrylate and 10 parts by mass of acrylic acid were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer. The weight-average molecular weight (Mw) of this acrylic polymer was measured by the method described above and was found to be 600,000.

[0148] 100 parts by mass of the obtained (meth)acrylic acid ester polymer, 3 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Mitsui Chemicals, product name "Takenate D-101E") as a crosslinking agent, and 0.5 parts by mass of an ionic compound (manufactured by Nippon Emulsifier Co., Ltd., product name "Aminoion AS100") as an antistatic agent were mixed in a solvent to obtain a coating solution for an adhesive composition for forming an adhesive layer.

[0149] (4) Formation of the interfacial ablation layer A silicone-based release agent layer was formed on one side of a polyethylene terephthalate film with a thickness of 38 μm (Lintec Corporation, product name "SP-PET381031"), and the adhesive composition coating liquid obtained in step (2) above was applied to the release surface of the release sheet, and the resulting coating film was dried by heating. As a result, a laminate was obtained in which the dried coating film formed an interfacial ablation layer with a thickness of 30 μm and the release sheet (hereinafter referred to as the "first release sheet") were laminated together.

[0150] (5) Formation of adhesive layer A silicone-based release agent layer was formed on one side of a polyethylene terephthalate film with a thickness of 38 μm (Lintec Corporation, product name "SP-PET381031") and the adhesive composition coating liquid obtained in step (3) above was applied to the release surface of the release sheet and the resulting coating film was dried by heating. As a result, a laminate was obtained in which a 10 μm thick adhesive layer formed by the drying of the coating film and the release sheet (hereinafter referred to as the "second release sheet") were laminated together.

[0151] (6) Preparation of work handling sheet By bonding the antistatic layer side of the laminate obtained in step (1) above with the interface ablation layer side of the laminate obtained in step (4) above, a laminate is obtained in which the first release sheet, interface ablation layer, antistatic layer, and substrate are laminated in order.

[0152] Furthermore, by bonding the substrate-side surface of the obtained laminate to the adhesive layer-side surface of the laminate obtained in step (5) above, a work handling sheet was obtained in which a first release sheet, an interfacial ablation layer, an antistatic layer, a substrate, an adhesive layer, and a second release sheet were laminated in that order.

[0153] [Examples 2-2 to 2-4, Comparative Example 2-1] Work handling sheets were obtained in the same manner as in Example 2-1, except that the type and content of the photosensitizer were changed as shown in Table 1.

[0154] [Comparative Examples 2-2 and 2-3] Work handling sheets were obtained in the same manner as in Example 2-1, except that an antistatic layer was not formed and the type and content of the photosensitizer were changed as shown in Table 1.

[0155] [Test Example 1] (Measurement of Surface Resistivity) Work handling sheets manufactured in the Examples and Comparative Examples were cut into 10 cm x 10 cm pieces to obtain measurement samples. The surface resistivity (Ω / sq) was measured in accordance with JIS K6911-1995 using the double-ring electrode method (two-terminal method) for the exposed surface (adhesive side) of the interface ablation layer exposed by peeling off the first release sheet from the measurement sample, and for the surface (back side) of the adhesive layer exposed by peeling off the second release sheet. For the back side in Examples 1-11 and 1-12, the surface resistivity of the substrate side was measured. The measuring apparatus used was an Advantest resistance meter (digital electrometer R8252) and an Advantest sample chamber TR42. The measurements were performed in an environment of 23°C and 50% RH, and the surface resistivity (Ω / sq) was calculated based on the current value when a voltage of 100V was applied for 1 minute. The results are shown in Tables 1 and 2.

[0156] [Test Example 2] (Evaluation of Laser Lift-Off Suitability) (1) Preparation of Chips on Work Handling Sheet (Preparation Process) The adhesive side of a dicing sheet (Lintec Corporation, product name "D-485H") was attached to one side of a silicon wafer (#2000, thickness: 24 μm). Next, a dicing ring frame was attached to the peripheral edge of the adhesive side of the dicing sheet (a position that does not overlap with the silicon wafer). Furthermore, the dicing sheet was cut to match the outer diameter of the ring frame. After that, the silicon wafer was diced into chips with a size of 0.3 mm × 0.3 mm (0.3 mm square) using a dicing device (Disco Corporation, product name "DFD6362").

[0157] Next, the second release sheet was peeled off from the work handling sheets manufactured in Examples 1-1 to 1-10, Comparative Examples 1-1 to 1-2, Examples 2-1 to 2-4, and Comparative Examples 2-1 to 2-3, and the exposed surface (adhesive surface) of the adhesive layer that was thus exposed was bonded to the glass substrate. On the other hand, for the work handling sheets manufactured in Examples 1-11 and 1-12, the following operation was performed without fixing them to the glass substrate. Next, the first release sheet was peeled off from the work handling sheet, and the exposed surface (adhesive surface) of the interface ablation layer that was thus exposed was bonded to the surface of the laminate obtained as described above where the multiple chips were located. After that, the dicing sheet was peeled off from the multiple chips. As a result, the multiple chips were transferred from the dicing sheet to the work handling sheet, and a laminate was obtained in which the multiple chips were provided on the work handling sheet.

[0158] (2) Arrangement of the laminate (arrangement process) Next, the laminate obtained as described above was arranged on the horizontally placed support plate so that the chip-side surfaces faced each other. At this time, the laminate and the support were arranged to be parallel and with a small gap between them.

[0159] (3) Irradiation with active energy rays (curing process) Subsequently, using an ultraviolet irradiation device equipped with a high-pressure mercury lamp as a light source (Lintec Corporation, product name "RAD-2000m / 12"), ultraviolet light is irradiated onto the work handling sheet side of the laminate described above (illuminance: 230 mW / cm²). ２ , Light amount: 380mJ / cm ２ By doing so, the interfacial ablation layer in the work handling sheet was cured overall.

[0160] (4) Separation of chips by laser irradiation (separation process) Finally, the laser irradiation device (YAG third harmonic (wavelength 355 nm) with a pulse width of 20 ns and a light intensity of 700 mJ / cm ２ Using a work handling sheet, laser light was irradiated onto the chip. In the case of the samples in Examples 1-1 to 1-10, Comparative Examples 1-1 to 1-2, Examples 2-1 to 2-4, and Comparative Examples 2-1 to 2-3, the light was irradiated from the glass substrate surface through the work handling sheet.

[0161] Specifically, a laser irradiation device (manufactured by Keyence Corporation, product name "MD-U1000C") was used to irradiate the chips with laser light through a work handling sheet. The irradiation was performed by irradiating a 2000 μm x 2000 μm area in the center of the chip, filling it in. At this time, the diameter of the laser spot was set to 25 μm, and the inner diameter of the ring resulting from the irradiation trajectory was set to 65 μm. The irradiation was performed on 10 chips (a group of 10 chips vertically x 1 chip horizontally) selected from among several chips.

[0162] The above irradiation was performed under the following conditions: frequency: 40 kHz, scan speed: 1000 mm / s, and irradiation dose: 25 μJ / shot.

[0163] (5) Confirmation of blistering and tip separation For work handling sheets and tips that have undergone irradiation as described above, the presence or absence of blistering at the interface between the substrate and the interface ablation layer on the work handling sheet, and the presence or absence of detachment of tips from the work handling sheet were confirmed, and the suitability for laser lift-off was evaluated based on the following criteria. The results are shown in Tables 1 and 2. ○...The number of tips that developed blisters and detached was 8 or more. ×...The number of tips that developed blisters and detached was less than 8.

[0164] [Test Example 3] (Evaluation of Re-adhesion Prevention) Following the evaluation in Test Example 2, under conditions of 23°C and 40% RH, the distance between the work handling sheet and the support plate was reduced to 100 μm to check whether the detached chips re-adhere to the work handling sheet. The re-adhesion prevention was evaluated based on the following criteria. The results are shown in Tables 1 and 2. ○: The number of chips that re-adheded was 20% or less of the number of detached chips. ×: The number of chips that re-adheded was more than 20% of the number of detached chips.

[0165] Further details regarding the abbreviations listed in Table 1 are as follows: PO: Polyolefin film PET: Polyethylene terephthalate film Takenate D-110N: Trimethylolpropane-modified xylylene diisocyanate (manufactured by Mitsui Chemicals, product name "Takenate D-110N") Coronate HL: Hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate HL")

[0166] Furthermore, details of the abbreviations and other terms listed in Table 2 are as follows: Coumarin-based photosensitizer: Product name "NF-CO01" manufactured by Nippon Chemical Industries, Ltd. (Coumarin-based photosensitizer, absorbance at 365 nm of a 10 ppm dimethylformamide solution (measured with a spectrophotometer): 0.97) Pyrazoline-based photosensitizer: Product name "NF-PY02" manufactured by Nippon Chemical Industries, Ltd. (Pyrazoline-based photosensitizer, absorbance at 365 nm of a 10 ppm dimethylformamide solution (measured with a spectrophotometer): 0.53)

[0167]

[0168]

[0169] As can be seen from Tables 1 and 2, the work handling sheets manufactured in the examples exhibited excellent laser lift-off suitability and were able to effectively separate chips while suppressing the effects of static electricity.

[0170] The work handling sheet of the present invention can be suitably used in the manufacture of displays and the like that which are equipped with micro-light-emitting diodes as pixels.

[0171] 1...Work handling sheet 11, 11'...Interface ablation layer 12...Substrate 13...Reaction area 2, 2'...Workpiece piece 3...Target object 4...Laser light 5...Blister

Claims

1. A work handling sheet comprising a base material and an interface ablation layer laminated on one side of the base material, capable of holding small workpieces, and subjected to interface ablation by laser irradiation, wherein the surface resistivity of the interface ablation layer on the side opposite to the base material is 1.5 × 10 １３ A work handling sheet characterized by having a density of Ω / sq or less.

2. The work handling sheet according to claim 1, characterized by containing an antistatic agent.

3. The work handling sheet according to claim 2, characterized in that the antistatic agent is contained in the base material.

4. The work handling sheet according to claim 2, characterized in that the work handling sheet comprises an antistatic layer containing the antistatic agent.

5. The work handling sheet according to claim 4, characterized in that the antistatic layer is laminated between the substrate and the interface ablation layer.

6. The work handling sheet according to claim 1, characterized in that the interface ablation layer contains an ultraviolet absorber.

7. The work handling sheet according to claim 1, characterized in that the interface ablation layer contains a photosensitizer.

8. The work handling sheet according to claim 7, characterized in that the photosensitizer is a compound having a heterocycle.

9. The work handling sheet according to claim 7, characterized in that the photosensitizer is at least one of a coumarin-based photosensitizer and a pyrazoline-based photosensitizer.

10. The work handling sheet according to claim 7, characterized in that the content of the photosensitizer in the interfacial ablation layer is 0.1% or more and 10% or less.

11. The work handling sheet according to claim 1, characterized in that when interfacial ablation is caused in the interfacial ablation layer, a blister is formed at the location where the interfacial ablation occurs.

12. The work handling sheet according to claim 1, characterized in that it is used to selectively separate any work piece from the interface ablation layer, which is held on the surface of the interface ablation layer opposite to the substrate, by interface ablation locally generated in the interface ablation layer.

13. A device manufacturing method comprising: a preparation step of preparing a laminate in which a plurality of workpieces are held on the surface of the interface ablation layer side of a work handling sheet according to any one of claims 1 to 12; a placement step of arranging the laminate on an object capable of receiving the workpieces such that the surfaces of the laminate on which the workpieces are held face to each other; and a separation step of irradiating a laser beam to a position on the interface ablation layer of the laminate to which at least one of the workpieces is attached, thereby causing interface ablation at the irradiated position in the interface ablation layer, separating the workpieces located at the position where interface ablation has occurred from the work handling sheet, and placing the workpieces on the object.

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