Workpiece handling sheet and device manufacturing method

Abstract

A workpiece handling sheet 1 comprises: 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 fragment, and is subjected to interface ablation by irradiation with laser light. The interface ablation layer 11 contains a photosensitizer, and the absorbance of light at a wavelength of 365 nm, as measured for a solution obtained by dissolving the photosensitizer in an organic solvent at a concentration of 10 ppm, is 0.3 or more. The workpiece handling sheet 1 can satisfactorily handle workpiece fragments of various sizes and thicknesses.

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 workpieces such as semiconductor components and semiconductor devices, and a device manufacturing method using the work handling sheet.

[0002] Semiconductor wafers such as silicon and gallium arsenide, and various packages are manufactured in a large-diameter state. These are cut and separated (dicing) into element chips (semiconductor chips) and individually peeled off (picked up), and then transferred to the next process, the mounting process. At this time, the workpiece such as a semiconductor wafer is processed such as back grinding, dicing, washing, drying, expanding, picking up, and mounting while being attached to a semiconductor processing sheet provided with a base material and an adhesive layer.

[0003] In the above-described picking up and mounting processes, semiconductor chips on the semiconductor processing sheet are individually picked up using a suction collet and placed at predetermined positions. At this time, the semiconductor chips are also pushed up from the back surface of the semiconductor processing sheet using needles, or the semiconductor processing sheet is expanded to separate the semiconductor chips from each other.

[0004] By the way, in recent years, in the development of displays using micro light-emitting diodes, the use of laser light irradiation has been studied for arranging individual micro light-emitting diodes on a substrate. For example, in Patent Document 1, after holding a plurality of micro light-emitting diodes on a support via a predetermined layer, laser light is irradiated on the layer to cause ablation of the layer at the irradiated position, and thereby a method of placing the micro light-emitting diodes separated (laser lift-off) from the support on a wiring substrate has been studied. Since laser light is excellent in directivity and convergence, it is easy to control the irradiation position and selective placement can be performed well.

[0005] Japanese Patent No. 6546278

[0006] However, further miniaturization of microlight-emitting diodes and higher-density mounting of microlight-emitting diodes are progressing, and in order to address these, there is a need for a means that can handle a large number of microlight-emitting diodes and other minute workpieces more efficiently than conventional methods such as those described in Patent Document 1.

[0007] On the other hand, semiconductor chips obtained by dicing semiconductor wafers are generally larger in size than micro-light-emitting diodes. Therefore, when attempting to use the aforementioned laser lift-off method as an alternative to semiconductor wafer pickup and mounting, there was a problem in that the semiconductor chips could not be properly separated.

[0008] This invention has been made in view of the above circumstances, and aims to provide a work handling sheet that can handle workpieces of various sizes and thicknesses well, and a device manufacturing method using the work handling sheet.

[0009] 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 irradiation with laser light, wherein the interface ablation layer contains a photosensitizer, and the absorbance of a 365 nm light beam measured with respect to a solution obtained by dissolving the photosensitizer in an organic solvent at a concentration of 10 ppm is 0.3 or higher (Invention 1).

[0010] The work handling sheet according to the above invention (Invention 1) contains a photosensitizer in the interfacial ablation layer that satisfies the absorbance conditions described above, so that when irradiated with laser light, interfacial ablation is effectively performed, thereby enabling good separation of workpiece pieces toward the target object. As a result, good laser lift-off is possible regardless of the size or thickness of the workpiece pieces being handled.

[0011] In the above invention (Invention 1), the photosensitizer is preferably a compound having a heterocycle (Invention 2).

[0012] In the above inventions (Inventions 1 and 2), it is preferable that the photosensitizer is at least one of a coumarin-based photosensitizer and a pyrazoline-based photosensitizer (Invention 3).

[0013] In the above inventions (Inventions 1 to 3), it is preferable that the content of the photosensitizer in the interfacial ablation layer is 0.1% or more and 10% or less (Invention 4).

[0014] In the above inventions (inventions 1 to 4), it is preferable that the content of the ultraviolet absorber in the interfacial ablation layer is 10% or less (invention 5).

[0015] In the above inventions (Inventions 1 to 5), it is preferable that the laser light has a wavelength in the ultraviolet region (Invention 6).

[0016] In the above inventions (inventions 1 to 6), 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 7).

[0017] In the above inventions (inventions 1 to 7), it is preferable that the interface ablation layer is used to selectively separate any workpiece from a plurality of workpieces held on the surface of the interface ablation layer opposite to the substrate, by locally generated interface ablation in the interface ablation layer (invention 8).

[0018] In the above inventions (Inventions 1 to 7), it is preferable that the interfacial ablation layer contains an active energy ray curable component (Invention 9).

[0019] In the above invention (Invention 9), it is preferable that the interface ablation layer is cured entirely or locally by irradiation with an active energy ray, and that local interface ablation is caused in the interface ablation layer by irradiation with a laser light, thereby selectively separating any workpiece from the interface ablation layer from any workpiece held on the surface of the interface ablation layer opposite to the substrate (Invention 10).

[0020] Secondly, the present invention provides a device manufacturing method (Invention 11) comprising: a preparation step of preparing a laminate in which a plurality of workpieces are held on the surface of the work handling sheet (Inventions 1 to 8) on the side of the interface ablation layer; a placement step of arranging the laminate on an object capable of receiving the workpieces such that the surfaces of the laminate on the side of the workpieces face 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.

[0021] Thirdly, the present invention provides 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 work handling sheet (inventions 9, 10) on the side of the interface ablation layer; a placement step of arranging the laminate on an object capable of receiving the workpieces such that the surfaces of the laminate on the side of the workpieces face each other; a curing step of curing the interface ablation layer, either entirely or locally, by irradiating the entire interface ablation layer of the laminate or the position on the interface ablation layer of the laminate where at least one of the workpieces is attached with active energy rays; and a separation step of irradiating the position on the interface ablation layer of the laminate where at least one of the workpieces is attached with laser light to cause interface ablation at the irradiated position in the interface ablation layer, thereby separating the workpieces located at the position where interface ablation has occurred from the work handling sheet and placing the workpieces on the object (invention 12).

[0022] In the above invention (Invention 12), it is preferable to perform the separation step after the completion of the hardening step (Invention 13).

[0023] In the above inventions (inventions 12 and 13), it is preferable to perform the irradiation of the laser light in the separation step in conjunction with the irradiation of the active energy ray in the curing step, thereby performing the local curing of the interface ablation layer and the interface ablation simultaneously (invention 14).

[0024] The work handling sheet according to the present invention can handle workpieces of various sizes and thicknesses effectively, and the device manufacturing method according to the present invention can produce devices with excellent performance.

[0025] 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 device manufacturing method using a work handling sheet according to one embodiment of the present invention. This is a cross-sectional view illustrating another example of a device manufacturing method using a work handling sheet according to one embodiment of the present invention. This is a cross-sectional view illustrating the state of blisters and reaction areas caused by laser irradiation.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Furthermore, the interface ablation layer 11 in this embodiment contains a photosensitizer. This photosensitizer is such 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.

[0032] In this embodiment, the presence of a photosensitizer exhibiting the above-mentioned absorbance in the interfacial ablation layer 11 improves the efficiency with which the interfacial ablation layer 11 receives energy from the laser light. In typical laser lift-off, the laser light used has a major peak around a wavelength of 365 nm, so using the above-mentioned photosensitizer dramatically improves energy efficiency compared to using other photosensitizers. As a result, interfacial ablation occurs effectively, and it becomes possible to separate the held workpiece pieces well from the interfacial ablation layer 11. In particular, even under conditions where separation was difficult with conventional workpiece handling sheets, considering the size and thickness of the workpiece pieces to be separated, and the laser irradiation method, the workpiece handling sheet 1 according to this embodiment enables good separation of workpiece pieces.

[0033] Furthermore, it is preferable that the interfacial ablation layer 11 in this embodiment also contains an active energy ray curable component in addition to the photosensitizer.

[0034] In this embodiment, the interfacial ablation layer 11 contains an active energy ray curable component, which allows for a reduction in the adhesion between the work handling sheet and the workpiece fragments by irradiation with active energy rays. Therefore, by reducing the adhesion by irradiation with active energy rays before or simultaneously with the interfacial ablation described above, it becomes possible to reliably separate the workpiece fragments from the work handling sheet according to this embodiment. Furthermore, it becomes possible to reduce the amount of laser light irradiation required to achieve sufficient separation of the workpiece fragments. Moreover, in the work handling sheet according to this embodiment, since the adhesion to the workpiece fragments is reduced by irradiation with active energy rays, it is also possible to set the adhesion level higher before irradiation with active energy rays. As a result, when transferring workpiece fragments from other sheets, etc., to the work handling sheet according to this embodiment, it becomes possible to prevent the residue of workpiece fragments on the other sheets, etc., and to achieve a good transfer.

[0035] 1. 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 workpieces, has the property of undergoing interface ablation by laser light irradiation, and contains a photosensitizer that satisfies the absorbance conditions described above.

[0036] 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.

[0037] (1) Acrylic polymer The acrylic polymer is not particularly limited as long as the interface ablation layer 11 (adhesive layer) can exhibit a predetermined adhesiveness. For example, the acrylic polymer preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or its derivative. In this specification, (meth)acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same applies to other similar terms.

[0038] The functional group-containing monomer is preferably a monomer having a polymerizable double bond and a functional group such as a hydroxy group, a carboxy group, an amino group, a substituted amino group, or an epoxy group in the molecule.

[0039] Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0040] Examples of the carboxy group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used alone or in combination of two or more.

[0041] Examples of the amino group-containing monomer or the substituted amino group-containing monomer include aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0042] As the (meth)acrylic acid ester monomer, in addition to an alkyl (meth)acrylate having an alkyl group with 1 to 20 carbon atoms, for example, a monomer having an alicyclic structure in the molecule (alicyclic structure-containing monomer) is preferably used.

[0043] As the alkyl (meth)acrylate, alkyl (meth)acrylates in which the number of carbon atoms of the alkyl group is particularly 1 to 18, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. are preferably used. These may be used alone or in combination of two or more.

[0044] As the monomer containing an alicyclic structure, for example, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, etc. are preferably used. These may be used alone or in combination of two or more.

[0045] The acrylic polymer preferably contains the structural unit derived from the above functional group-containing monomer in a proportion of 1% by mass or more, particularly preferably 5% by mass or more, and more preferably 10% by mass or more. Further, the acrylic polymer contains the structural unit derived from the above functional group-containing monomer in a proportion of preferably 35% by mass or less, particularly preferably 30% by mass or less, and more preferably 25% by mass or less.

[0046] Further, the acrylic polymer preferably contains the structural unit derived from the (meth)acrylic acid ester monomer or its derivative in a proportion of 50% by mass or more, particularly preferably 60% by mass or more, and more preferably 70% by mass or more. Also, the acrylic polymer contains the structural unit derived from the (meth)acrylic acid ester monomer or its derivative in a proportion of preferably 99% by mass or less, particularly preferably 95% by mass or less, and more preferably 90% by mass or less.

[0047] The acrylic polymer can be obtained by copolymerizing the above functional group-containing monomer and the (meth)acrylic acid ester monomer or its derivative by a conventional method. In addition to these monomers, dimethylacrylamide, vinyl formate, vinyl acetate, styrene, etc. may also be copolymerized.

[0048] 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).

[0049] (2) Active Energy Ray Curable Component As described above, the interfacial ablation layer 11 in this embodiment may also contain an active energy ray curable component in addition to the photosensitizer. The active energy ray curable component is not particularly limited as long as it is possible to cure the interfacial ablation layer 11 by irradiation with active energy rays. When the interfacial ablation layer 11 in this embodiment contains an active energy ray curable component, it is preferable that the interfacial ablation layer 11 consists of an adhesive composition containing the active energy ray curable component and the photosensitizer described above.

[0050] Furthermore, the active energy ray curable component may consist mainly of a polymer having active energy ray curability, or it may consist mainly of a mixture of an active energy ray non-curable polymer (a polymer that does not have active energy ray curability) and a monomer and / or oligomer having at least one active energy ray curable group. Alternatively, it may be a mixture of an active energy ray curable polymer and an active energy ray non-curable polymer, or a mixture of an active energy ray curable polymer and a monomer and / or oligomer having at least one active energy ray curable group, or a mixture of all three.

[0051] First, we will explain the case where the active energy ray curable component mainly consists of a polymer that is curable by active energy rays.

[0052] The polymer having active energy ray curability is preferably a (meth)acrylic acid ester (co)polymer (A) (hereinafter sometimes referred to as "active energy ray curable polymer (A)") in which an energy ray curable functional group (active energy ray curable group) is introduced into the side chain. This active energy ray curable polymer (A) is preferably obtained by reacting an acrylic copolymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group that is bonded to the functional group.

[0053] Furthermore, the active energy ray-curable polymer (A) can exhibit a predetermined level of tackiness, similar to the acrylic polymer described in item (1) above. Therefore, when forming the interfacial ablation layer 11 using an adhesive composition containing the active energy ray-curable polymer (A), the adhesive composition does not need to contain the acrylic polymer described in item (1) above.

[0054] The acrylic copolymer (a1) preferably contains structural units derived from functional group-containing monomers and structural units derived from (meth)acrylic acid ester monomers or derivatives thereof. The functional group-containing monomers and (meth)acrylic acid ester monomers here are the same as those used as structural units of the acrylic polymer described in item (1) above. Furthermore, the content of these monomers in the acrylic copolymer (a1) is preferably the same as that of the acrylic polymer described in item (1) above.

[0055] The acrylic copolymer (a1) can be obtained by copolymerizing a functional group-containing monomer as described above with a (meth)acrylic acid ester monomer or its derivative by a conventional method. In addition to these monomers, dimethylacrylamide, vinyl formate, vinyl acetate, styrene, etc., may also be copolymerized.

[0056] An active energy ray curable polymer (A) is obtained by reacting an acrylic copolymer (a1) having the above-mentioned functional group-containing monomer units with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group.

[0057] The functional group of the unsaturated group-containing compound (a2) can be appropriately selected according to the type of functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, if the functional group of the acrylic copolymer (a1) is a hydroxyl group, an amino group, or a substituted amino group, the functional group of the unsaturated group-containing compound (a2) is preferably an isocyanate group or an epoxy group. If the functional group of the acrylic copolymer (a1) is an epoxy group, the functional group of the unsaturated group-containing compound (a2) is preferably an amino group, a carboxyl group, or an aziridinyl group.

[0058] Furthermore, the above-mentioned unsaturated group-containing compound (a2) 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 (a2) 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.

[0059] The above unsaturated group-containing compound (a2) 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 in the above acrylic copolymer (a1). Furthermore, the above unsaturated group-containing compound (a2) 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 in the above acrylic copolymer (a1).

[0060] In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), 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 copolymer (a1) and the functional groups present in the unsaturated group-containing compound (a2). As a result, the functional groups present in the acrylic copolymer (a1) react with the functional groups in the unsaturated group-containing compound (a2), introducing unsaturated groups into the side chains of the acrylic copolymer (a1), and yielding an active energy ray-curable polymer (A).

[0061] The weight-average molecular weight (Mw) of the activated energy ray-curable polymer (A) 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.

[0062] Even if the active energy ray curable component mainly consists of an active energy ray curable polymer (A), the active energy ray curable component may further contain an energy ray curable monomer and / or oligomer (B).

[0063] As the active energy ray curable monomer and / or oligomer (B), for example, an ester of a polyhydric alcohol and (meth)acrylic acid can be used.

[0064] Examples of such active energy ray curable monomers and / or oligomers (B) include monofunctional acrylic acid esters such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate, polyfunctional acrylic acid esters such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and dimethylol tricyclodecane di(meth)acrylate, as well as polyester oligo(meth)acrylate and polyurethane oligo(meth)acrylate.

[0065] When an active energy ray-curable polymer (A) is combined with an active energy ray-curable monomer and / or oligomer (B), the content of the active energy ray-curable monomer and / or oligomer (B) in the active energy ray-curable adhesive is preferably more than 0 parts by mass, and particularly preferably 60 parts by mass or more, per 100 parts by mass of the active energy ray-curable polymer (A). Furthermore, the content is preferably 250 parts by mass or less, and particularly preferably 200 parts by mass or less, per 100 parts by mass of the active energy ray-curable polymer (A).

[0066] Next, we will explain the case where the active energy ray curable component mainly consists of a mixture of an active energy ray non-curable polymer component and a monomer and / or oligomer having at least one active energy ray curable group.

[0067] As the active energy ray non-curing polymer component, for example, the same component as the acrylic copolymer (a1) described above can be used.

[0068] The monomer and / or oligomer having at least one active energy ray curable group can be the same as component (B) described above. The blending ratio of the active energy ray non-curable polymer component to the monomer and / or oligomer having at least one active energy ray curable group is preferably 1 part by mass or more of the monomer and / or oligomer having at least one active energy ray curable group per 100 parts by mass of the active energy ray non-curable polymer component, and particularly preferably 60 parts by mass or more. Furthermore, the blending ratio is preferably 200 parts by mass or less of the monomer and / or oligomer having at least one active energy ray curable group per 100 parts by mass of the active energy ray non-curable polymer component, and particularly preferably 160 parts by mass or less.

[0069] (3) Photosensitizer The photosensitizer in this embodiment is not particularly limited, as long as it satisfies the condition that the absorbance of light at a wavelength of 365 nm measured with respect to a solution obtained by dissolving the photosensitizer in an organic solvent at a concentration of 10 ppm is 0.3 or higher.

[0070] 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.

[0071] In this embodiment, the photosensitizer is preferably a compound having a heterocycle, from the viewpoint of easily satisfying the absorbance conditions described above. The number of heterocycles in the compound may be one or two or more. Furthermore, the compound may have a carbocyclic ring in addition to the heterocycle.

[0072] 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.

[0073] 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.

[0074] 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 easily achieving the absorbance described above and thereby easily realizing good interfacial ablation.

[0075] 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.

[0076] (4) 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 an acrylic polymer or an active energy ray curable polymer (A) 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, and reactive phenolic resins.

[0077] 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 or active energy ray curable polymer (A). Furthermore, the amount of crosslinking agent is preferably 20 parts by mass or less, particularly preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the acrylic polymer or active energy ray curable polymer (A).

[0078] (5) Photopolymerization initiator If the interfacial ablation layer 11 in this embodiment contains an active energy ray curable component, it is also preferable that the aforementioned adhesive composition contains a photopolymerization initiator. The photopolymerization initiator is not particularly limited. By containing a photopolymerization initiator in the interfacial ablation layer 11 in this embodiment, it becomes possible to effectively cure the interfacial ablation layer 11 while reducing the polymerization curing time and light irradiation amount of the interfacial ablation layer 11, especially when ultraviolet light is used as the active energy ray.

[0079] Specifically, photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl Tyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholino-phenyl)butan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy- Methylpropanone, ethanolone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(0-acetyloxime), benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethyl Examples include thioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2-benzyl-2-(dimethylamino)-4'-morpholinobtyrophenone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. These may be used individually or in combination of two or more.

[0080] Among the photopolymerization initiators mentioned above, it is preferable to use at least one of 1-hydroxycyclohexylphenyl ketone and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropan-1-one.

[0081] The content of the photopolymerization initiator in the adhesive composition is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of the active energy ray curable component. Furthermore, the above content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the active energy ray curable component. By having the photopolymerization initiator content within the above range, the interfacial ablation layer 11 can be effectively cured more easily.

[0082] (6) Other Components The interface ablation layer 11 may appropriately contain other components other than those described above. Examples of other components include ultraviolet absorbers. The presence of an ultraviolet absorber in the interface ablation layer 11 may improve the efficiency with which the interface ablation layer 11 receives energy from laser light. On the other hand, depending on the type and amount of photosensitizer, it may be easier to produce good interface ablation if the interface ablation layer 11 does not contain an ultraviolet absorber or contains only a very small amount. Therefore, even when an ultraviolet absorber is used, the amount of ultraviolet absorber in the interface ablation layer 11 is preferably less than 10%, particularly preferably 5% or less, and even more preferably 1% or less. If the interface ablation layer 11 contains an ultraviolet absorber, its content is preferably 0.1% or more.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] (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.

[0087] 2. 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] In this embodiment, the thickness of the base material 12 is preferably 10 μm or more, particularly preferably 30 μm or more, and even more preferably 50 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.

[0092] 3. 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.

[0093] 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.

[0094] 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.

[0095] 4. 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 individualized adhesive layers are laminated. The chip can be easily fixed to the object on which the workpiece piece is mounted by these individualized adhesive layers. 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.

[0096] 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.

[0097] 5. 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.

[0098] 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.

[0099] 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, 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.

[0100] 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.

[0101] 6. Method of Using the Work Handling Sheet The work handling sheet 1 according to the present embodiment can be suitably used for handling small workpieces. As described above, in the work handling sheet 1 according to the present embodiment, since the interfacial ablation layer 11 efficiently undergoes interfacial ablation by irradiation with laser light, small workpieces held on the interfacial ablation layer 11 can be separated with high precision toward a predetermined position.

[0102] As an example of the method of using the work handling sheet 1 according to the present embodiment, there is a method of selectively separating an arbitrary small workpiece among a plurality of small workpieces held on the surface of the interfacial ablation layer 11 opposite to the base material 12 in the interfacial ablation layer 11 by means of locally generated interfacial ablation in the interfacial ablation layer 11.

[0103] In the above method of use, the plurality of small workpieces held on the interfacial ablation layer 11 may be obtained by fragmenting a workpiece (the material of the small workpiece) held on the surface of the interfacial ablation layer 11 opposite to the base material 12 on that surface. That is, the small workpieces may be obtained by dicing the workpiece on the interfacial ablation layer 11. Alternatively, the small workpieces may be those formed independently of the work handling sheet 1 according to the present embodiment and placed on the interfacial ablation layer 11.

[0104] In addition, when the work handling sheet 1 according to the present embodiment includes the above-described adhesive layer or protective film forming layer, it is preferable to dice these layers and the workpiece on the interfacial ablation layer 11. Thereby, small workpieces in which those formed by fragmenting these layers are laminated can be obtained.

[0105] 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 0.3 mm or more, particularly preferably 1 mm or more, and even more preferably 1.5 mm or more. Furthermore, the minimum side length is preferably 50 mm or less, particularly preferably 20 mm or less, and even more preferably 10 mm or less. On the other hand, the area is 0.09 mm². ２ Those smaller than (for example, 10 μm) ２ ~0.09 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.

[0106] 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.

[0107] 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)).

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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 4 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.

[0114] The device manufacturing method described above may include steps other than the preparation, placement, and separation steps. For example, grinding, die bonding, wire bonding, molding, inspection, transfer, etc., may be performed at any time between the preparation and separation steps.

[0115] If the work handling sheet 1 according to this embodiment includes an interfacial ablation layer 11 containing an active energy ray curable component, it is also preferable to use it in the device manufacturing method shown in Figure 3. This device manufacturing method comprises at least four steps: a preparation step (Figure 3(a)), a placement step (Figure 3(b)), a curing step (Figure 3(c)), and a separation step (Figures 3(d) and (e)).

[0116] The preparation and placement steps in the device manufacturing method shown in Figure 3 can be carried out in the same manner as those in the device manufacturing method shown in Figure 2.

[0117] In the curing step following the preparation and placement steps, as shown in Figure 3(c), the entire interface ablation layer 11 in the laminate is irradiated with active energy rays 6 to cure the interface ablation layer 11 as a whole. As a result, the interface ablation layer 11 becomes a cured interface ablation layer 11'. Although Figure 3(c) depicts the irradiation of the entire interface ablation layer 11 with active energy rays 6, the irradiation may be performed only on the interface ablation layer 11 at the location where at least one workpiece 2 is attached, thereby curing the interface ablation layer 11 locally.

[0118] The irradiation with the activated energy rays 6 described above may be carried out 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, which is also used in the separation process described later, may be used.

[0119] Subsequently, in the separation process, as shown in Figure 3(d), a laser beam 4 is first irradiated onto the position where at least one workpiece 2 is attached in the hardened interface ablation layer 11' of the laminate. 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 beam 4 are not limited as long as they are capable of causing interface ablation. Known laser beam irradiation devices can be used for irradiation.

[0120] As shown in Figure 3(e), irradiation with the laser light 4 described above can cause interfacial ablation at the irradiated location in the hardened 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 hardened interfacial ablation layer 11' to deform locally at the location of the workpiece 2', causing the workpiece 2' to separate as it peels off the hardened 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] Furthermore, 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'. That is, as in the case shown in Figure 4, the blister 5 after separation is usually somewhat deflated compared to the blister 5 during separation.

[0122] Furthermore, when both the irradiation with the active energy ray 6 in the curing process and the irradiation with the laser light 4 in the separation process are performed using the laser light irradiation device described above, the curing process and the separation process may be performed simultaneously. That is, the irradiation with the laser light 4 in the separation process may also serve as the irradiation with the active energy ray 6 in the curing process, thereby simultaneously performing local curing and interface ablation of the interface ablation layer 11. In this case, the peak wavelength of the irradiated laser light 4 is preferably 300 nm or more, particularly preferably 310 nm or more, and even more preferably 350 nm or more. In addition, the peak wavelength is preferably 400 nm or less, particularly preferably 390 nm or less, and even more preferably 380 nm or less. Irradiating with laser light 4 having such a wavelength makes it easier to promote good curing and interface ablation of the interface ablation layer 11.

[0123] On the other hand, as shown in Figure 3, when the curing process and the separation process are carried out as independent processes, the active energy rays 6 irradiated from the ultraviolet irradiation device (particularly a device equipped with an ultraviolet LED as a light source, and a laser light irradiation device) used in the curing process preferably have a peak wavelength of 300 nm or more, more preferably 310 nm or more, and even more preferably 320 nm or more. Furthermore, the peak wavelength is preferably 400 nm or less, particularly preferably 390 nm or less, and even more preferably 380 nm or less. Similarly, the laser light 4 irradiated from the laser light irradiation device used in the separation process preferably has a peak wavelength of 300 nm or more, particularly preferably 310 nm or more, and even more preferably 320 nm or more. Furthermore, the peak wavelength is preferably 400 nm or less, particularly preferably 390 nm or less, and even more preferably 380 nm or less. In the curing and separation processes, irradiating with the active energy ray 6 and laser light 4 having the peak wavelengths described above, respectively, facilitates the smooth progression of curing and ablation of the interface ablation layer 11 in each process.

[0124] The device manufacturing method shown in Figure 3 above may include steps other than the preparation step, placement step, curing 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.

[0125] 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.

[0126] 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.

[0127] For example, other layers may be laminated between the interface ablation layer 11 and the substrate 12 in the work handling sheet 1 according to this embodiment, or on the surface of the substrate 12 opposite to the interface ablation layer 11. A specific example of such other layer 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).

[0128] 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.

[0129] [Example 1-1] (1) Preparation of adhesive composition 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 1,000,000.

[0130] 100 parts by mass (based on solid content, the same applies hereinafter) of an acrylic polymer in which an active energy ray curable group has been introduced into the side chain, obtained above, 3 parts by mass of 1-hydroxycyclohexyl-phenyl-ketone (manufactured by IGM Resins, product name "Omnirad 184") as a photopolymerization initiator, and 3 parts by mass of Nippon Chemical Industries' product name "NF-CO01" (coumarin-based photosensitizer, absorbance at 365 nm of a 10 ppm dimethylformamide solution (measured with a spectrophotometer): 0.97) were mixed in a solvent to obtain a coating solution for an adhesive composition.

[0131] (2) Formation of interfacial ablation layer (adhesive layer) A release sheet (Lintec Corporation, product name "SP-PET381031"), which has a silicone-based release agent layer formed on one side of a polyethylene terephthalate film with a thickness of 38 μm, was coated with the adhesive composition solution obtained in step (1) above, 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 5 μm and the release sheet were laminated together.

[0132] (3) Preparation of work handling sheet A work handling sheet with a release sheet attached was obtained by bonding the interfacial ablation layer side of the laminate obtained in step (2) above to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "T-910 WM19", thickness: 50 μm) as a base material.

[0133] 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℃

[0134] [Examples 1-2 and Comparative Example 1-1] Work handling sheets with release sheets attached were obtained in the same manner as in Example 1-1, except that the content of the photopolymerization initiator and the content of the photosensitizer were changed as shown in Table 1.

[0135] [Examples 1-3] (1) Preparation of adhesive composition 90 parts by mass of 2-ethylhexyl acrylate, 1.75 parts by mass of acryloyl morpholine, 3.5 parts by mass of 2-hydroxyethyl acrylate, 3.5 parts by mass of 4-hydroxybutyl acrylate, and 0.2 parts by mass of acrylic acid were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer (acrylic polymer). The weight-average molecular weight (Mw) of this acrylic polymer was measured by the method described above and was found to be 1 million.

[0136] 100 parts by mass of the acrylic polymer obtained above, 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 product name "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. were mixed in a solvent to obtain a coating solution for an adhesive composition.

[0137] A work handling sheet with a release sheet attached was obtained in the same manner as in Example 1-1, except that the obtained adhesive composition was used.

[0138] [Examples 1-4 to 1-15 and Comparative Example 1-2] Work handling sheets with release sheets attached were obtained in the same manner as in Example 1-3, except that the crosslinking agent content, photosensitizer content, and the thickness of the interfacial ablation layer were changed as shown in Table 1.

[0139] [Test Example 1-1] (Laser Lift-Off Test) (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 the polished surface of a silicon wafer, which had been polished on one side with #2000 grit. Next, a dicing ring frame was attached to the periphery 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 using a dicing device (Disco Corporation, product name "DFD6362"). The thickness of the silicon wafer used and the size of the diced chips are as shown in Table 1.

[0140] Next, the release sheet was peeled off from the work handling sheet manufactured in the examples and comparative examples, and the exposed surface 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. This transferred the multiple chips 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.

[0141] (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.

[0142] (3) Separation of chips by laser irradiation (separation process) Next, a laser irradiation device (YAG third harmonic (wavelength 355 nm) with a pulse width of 20 ns and a light intensity of 700 mJ / cm) is used. ２ Using a work handling sheet, laser light was shone onto the chip. The irradiation conditions were: frequency: 40 kHz, irradiation dose: 50 μJ / shot.

[0143] The irradiation in this case involved sequentially irradiating with point-like laser beams, so that the trajectories formed multiple lines parallel to each other. Furthermore, the irradiation was performed so that the area formed by these multiple linear trajectories was located in the center of the chip. The order of irradiation with point-like laser beams was to start from one end of a trajectory and irradiate sequentially toward the other end, and then repeat the process for adjacent trajectories, starting from one end on the same side and irradiating sequentially toward the other end.

[0144] Here, irradiation was performed such that the diameter of a single irradiation mark produced by the irradiation was 20 μm, and the distance between adjacent irradiation marks within a single trajectory was 5 μm. Furthermore, irradiation was performed so that the distance between trajectories was as shown in Table 1.

[0145] The irradiation described above was performed on each of 100 chips (groups of 10 chips vertically and 10 chips horizontally) selected from among several chips.

[0146] (4) Evaluation The laser lift-off performed as described above was checked to see if the tips detached from the work handling sheet, and the suitability of the laser lift-off was evaluated based on the following criteria. The results are shown in Table 1. ◎...The percentage of tips that detached successfully was 55% or more. ○...The percentage of tips that detached successfully was greater than 0% but less than 55%. ×...The percentage of tips that detached successfully was 0%.

[0147] The details of the abbreviations listed in Table 1 are as follows: 2EHA: 2-ethylhexyl acrylate HEA: 2-hydroxyethyl acrylate MOI: methacryloyloxyethyl isocyanate ACMO: acryloylmorpholine 4HBA: 4-hydroxybutyl acrylate AAc: acrylic acid

[0148]

[0149] As can be seen from Table 1, it was found that the work handling sheet according to the example resulted in good chip detachment.

[0150] [Example 2-1] (1) Preparation of adhesive composition 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 above and was found to be 1 million.

[0151] 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, 4.69 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Mitsui Chemicals, product name "Takenate D-101E") as a crosslinking agent, 3 parts by mass of 1-hydroxycyclohexyl-phenyl-ketone (manufactured by IGM Resins, product name "Omnirad 184") as a photopolymerization initiator, and 3 parts by mass of Nippon Chemical Industries, Ltd.'s product name "NF-CO01" (coumarin-based photosensitizer, absorbance at 365 nm of a 10 ppm dimethylformamide solution (measured with a spectrophotometer): 0.97): were mixed in a solvent to obtain a coating solution for an adhesive composition.

[0152] (2) Formation of interfacial ablation layer (adhesive layer) A release sheet (Lintec Corporation, product name "SP-PET381031"), which has a silicone-based release agent layer formed on one side of a polyethylene terephthalate film with a thickness of 38 μm, was coated with the adhesive composition solution obtained in step (1) above, 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 5 μm and the release sheet were laminated together.

[0153] (3) Preparation of work handling sheet A work handling sheet with a release sheet attached was obtained by bonding the interfacial ablation layer side of the laminate obtained in step (2) above to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "T-910 WM19", thickness: 50 μm) as a base material.

[0154] [Examples 2-2 to 2-16, Examples 2-18 to 2-26, Comparative Example 2-1 and Comparative Examples 2-3 to 2-4] Work handling sheets with release sheets attached were obtained in the same manner as in Example 2-1, except that the composition of the acrylic polymer, the type and amount of crosslinking agent, the type and amount of photopolymerization initiator, the type and amount of photosensitizer, the amount of ultraviolet absorber, and the thickness of the interfacial ablation layer were changed as shown in Table 2.

[0155] Furthermore, tris[2,4,6-[2-{4-(octyl-2-methylethanol)oxy-2-hydroxyphenyl}]-1,3,5-triazine (hydroxyphenyltriazine-based UV absorber, manufactured by BASF, product name "Tinuvin 477") was used as the UV absorber.

[0156] Furthermore, details of the abbreviations and other terms listed in Table 2 are as follows: [Acrylic polymers] 2EHA: 2-ethylhexyl acrylate HEA: 2-hydroxyethyl acrylate MOI: methacryloyloxyethyl isocyanate ACMO: acryloylmorpholine MA: methacrylic acid AA: acrylic acid [Crosslinking agents] Takenate D-101E: trimethylolpropane-modified tolylene diisocyanate (manufactured by Mitsui Chemicals, Inc., product name "Takenate D-101E") Coronate HL: hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate HL") [Photopolymerization initiator] Omnirad 184: 1-hydroxycyclohexyl-phenyl-ketone (manufactured by IGM Resins, Inc., product name "Omnirad 184") Omnirad127: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (manufactured by IGM Resins, product name "Omnirad127") [Photosensitizers] Coumarin-based: 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) Pyrazolin-based: Product name "NF-PY02" manufactured by Nippon Chemical Industries, Ltd. (Pyrazolin-based photosensitizer, absorbance at 365 nm of a 10 ppm ethanol solution (measured with a spectrophotometer): 0.53)

[0157] [Example 2-17] 40 parts by mass of 2-ethylhexyl acrylate, 50 parts by mass of methacrylic acid, 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 the acrylic polymer was measured by the method described above and was found to be 1 million.

[0158] 100 parts by mass (based on solid content, the same applies hereinafter) of the acrylic polymer obtained above, 40 parts by mass of a decahertz urethane acrylate (manufactured by Nippon Synthetic Chemical Industries, Ltd., product name "UV-5806", weight-average molecular weight: 1740) as an active energy ray curable oligomer, 4.69 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Mitsui Chemicals, Ltd., product name "Takenate D-101E") as a crosslinking agent, and 1.5 parts by mass of Nippon Chemical Industries, Ltd., product name "NF-CO01" (coumarin-based photosensitizer, absorbance at 365 nm of a 10 ppm dimethylformamide solution (measured with a spectrophotometer): 0.97): were mixed in a solvent to obtain a coating solution for an adhesive composition.

[0159] A work handling sheet with a release sheet attached was obtained in the same manner as in Example 2-1, except that the adhesive composition obtained above was used and the thickness of the interfacial ablation layer was changed as shown in Table 2.

[0160] [Comparative Example 2-2] A work handling sheet with a release sheet attached was obtained in the same manner as in Example 2-17, except that the crosslinking agent content was changed as shown in Table 2, no photosensitizer was used, and the thickness of the interfacial ablation layer was changed as shown in Table 2.

[0161] [Test Example 2-1] (Laser Lift-Off Test) (1) Preparation of Chips on Work Handling Sheet (Preparation Step) Similar to the preparation step in Test Example 1-1, a laminate was obtained in which multiple chips were placed on a work handling sheet. The thickness of the silicon wafer used and the size of the diced chips are as shown in Table 2.

[0162] (2) Arrangement of the laminate (arrangement process) Similar to the arrangement process in Test Example 1-1, the laminate obtained as described above was arranged so that the chip-side surfaces faced each other on a horizontally placed support plate.

[0163] (3) Irradiation with active energy rays (curing process) Subsequently, using an ultraviolet irradiation device (Lintec Corporation, product name "RAD-2000") equipped with a high-pressure mercury lamp as a light source, 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.

[0164] (4) Separation of chips by laser irradiation (separation process) Similar to the separation process in Test Example 1-1, laser light was irradiated onto the chips through the work handling sheet. The spacing between the irradiation trajectories was as shown in Table 2.

[0165] (5) Evaluation was performed in the same manner as in the evaluation of the evaluation test example 1-1. The results are shown in Table 2.

[0166]

[0167] As can be seen from Table 2, it was found that the work handling sheet according to the embodiment resulted in good chip detachment.

[0168] The work handling sheet of the present invention can be suitably used for handling various small workpieces, such as micro light-emitting diodes and semiconductor components.

[0169] 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 6...Activated energy ray

Claims

Substrate and The substrate is laminated on one side, capable of holding a small workpiece, and undergoes interface ablation by irradiation with laser light. A work handling sheet equipped with, The aforementioned interface ablation layer contains a photosensitizer, The absorbance of a light source at a wavelength of 365 nm measured with a solution obtained by dissolving the aforementioned photosensitizer in an organic solvent at a concentration of 10 ppm is 0.3 or higher. A work handling sheet characterized by the following features. 　 The work handling sheet according to claim 1, characterized in that the photosensitizer is a compound having a heterocycle. 　 The work handling sheet according to claim 1, characterized in that the photosensitizer is at least one of a coumarin-based photosensitizer and a pyrazoline-based photosensitizer. 　 The work handling sheet according to claim 1, characterized in that the content of the photosensitizer in the interfacial ablation layer is 0.1% or more and 10% or less. 　 The work handling sheet according to claim 1, characterized in that the content of the ultraviolet absorber in the interfacial ablation layer is 10% or less. 　 The work handling sheet according to claim 1, characterized in that the laser light has a wavelength in the ultraviolet region. 　 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. 　 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. 　 The work handling sheet according to claim 1, characterized in that the interfacial ablation layer contains an active energy ray curable component. 　 The work handling sheet according to claim 9, characterized in that it is used to selectively separate any work piece from the interface ablation layer from the interface ablation layer by curing the interface ablation layer whole or locally by irradiation with active energy rays and by causing localized interface ablation in the interface ablation layer by irradiation with laser light. 　 A preparation step of preparing a laminate in which a plurality of workpiece pieces are held on the surface on the interface ablation layer side of the work handling sheet according to any one of claims 1 to 8, A positioning step of arranging the laminate such that the side of the laminate facing the workpiece is facing the object capable of receiving the workpiece, A separation step is to irradiate the interface ablation layer in the laminate with laser light at a position where at least one of the workpiece pieces is attached, thereby causing interface ablation at the irradiated position in the interface ablation layer, thereby separating the workpiece piece located at the position where interface ablation has occurred from the work handling sheet, and placing the workpiece piece on the object. A device manufacturing method characterized by comprising the following: 　 A preparation step for preparing a laminate in which a plurality of workpiece pieces are held on the surface on the interface ablation layer side of the work handling sheet according to claim 9 or 10, A positioning step of arranging the laminate such that the side of the laminate facing the workpiece is facing the object capable of receiving the workpiece, A curing step of curing the interface ablation layer, either entirely or locally, by irradiating the entire interface ablation layer in the laminate with an active energy ray, or to the location on the interface ablation layer in the laminate where at least one of the workpiece pieces is attached. A separation step is to irradiate the interface ablation layer in the laminate with laser light at a position where at least one of the workpiece pieces is attached, thereby causing interface ablation at the irradiated position in the interface ablation layer, thereby separating the workpiece piece located at the position where interface ablation has occurred from the work handling sheet, and placing the workpiece piece on the object. A device manufacturing method characterized by comprising the following: 　 The device manufacturing method according to claim 12, characterized in that the separation step is performed after the completion of the curing step. 　 The device manufacturing method according to claim 12, characterized in that the irradiation of the laser light in the separation step also serves as the irradiation of the active energy ray in the curing step, thereby simultaneously performing local curing of the interface ablation layer and interface ablation.

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