Work handling sheet

Abstract

To provide a work handling sheet with which chip scattering hardly occurs even in a case where dicing is performed.SOLUTION: A work handling sheet comprises: a substrate; and an interface ablation layer which is laminated on one face side in the substrate and capable of holding a small work piece and performs interface ablation by being irradiated with a laser beam. The interface ablation layer contains an ultraviolet absorber. When a thickness of the interface ablation layer is defined as T (μm) and a loop tack value of a face in the interface ablation layer on an opposite side of the substrate with respect to a mirror face of a silicon wafer is defined as L (mN / 25 mm), in the work handling sheet, an evaluation value calculated from the following formula (1): evaluation value=L / T2 is 10 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a workpiece handling sheet that can be used to handle small workpieces such as semiconductor components and semiconductor devices. [Background technology]

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

[0003] In the above-mentioned pick-up and mounting process, the semiconductor chips on the semiconductor processing sheet are individually picked up using a suction collet and placed in a predetermined position. At this time, the semiconductor chips may be pushed up from the backside 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] Recently, in the development of displays using micro light-emitting diodes, the use of laser light irradiation to arrange individual micro light-emitting diodes on a substrate has been considered. For example, Patent Document 1 discusses a method in which multiple micro light-emitting diodes are held on a support via a predetermined layer, and then the layer is irradiated with laser light to cause ablation of the layer at the irradiated position, thereby separating the micro light-emitting diodes from the support (laser lift-off), and then mounting the micro light-emitting diodes on a wiring substrate. Laser light has excellent directionality and convergence, making it easy to control the irradiation position and allowing for good selective mounting. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6546278 Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of the semiconductor processing sheet described above, after a semiconductor wafer is diced on the sheet to separate it into semiconductor chips, the same sheet may be used to carry out a semiconductor chip pick-up process.

[0007] Similarly, the inventors have considered performing laser lift-off following the dicing process using the sheet for laser lift-off described above, but have discovered that chips are likely to fly off during dicing when using a sheet specifically designed for laser lift-off.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a workpiece handling sheet that is less likely to cause chip scattering even when dicing is performed. [Means for solving the problem]

[0009] In order to achieve the above object, first, the present invention provides a workpiece handling sheet including a substrate and an interfacial ablation layer laminated on one side of the substrate, capable of holding a small workpiece, and capable of interfacial ablation by irradiation with laser light, wherein the interfacial ablation layer contains an ultraviolet absorber, and the thickness of the interfacial ablation layer is T (μm), and the loop tack value of the surface of the interfacial ablation layer opposite the substrate to the mirror surface of a silicon wafer is L (mN / 25 mm), where T is the thickness of the interfacial ablation layer, and L is the loop tack value of the surface of the interfacial ablation layer opposite the substrate, as expressed by the following formula (1): Evaluation value = L / T 2 …(1) The present invention provides a work handling sheet characterized in that the evaluation value calculated from the above is 10 or more (Invention 1).

[0010] The workpiece handling sheet according to the above invention (Invention 1) satisfies the above-mentioned evaluation value conditions, so that chip scattering is unlikely to occur even when dicing is performed on the sheet. Furthermore, the interfacial ablation layer contains an ultraviolet absorber, which can cause good interfacial ablation and enable good selective separation of the individual chips.

[0011] In the above invention (Invention 1), the thickness T of the interface ablation layer is preferably 15 μm or less (Invention 2).

[0012] In the above inventions (Inventions 1 and 2), the loop tack value L is preferably 800 mN / 25 mm or more and 2500 mN / 25 mm or less (Invention 3).

[0013] In the above inventions (Inventions 1 to 3), the interface ablation layer is preferably an adhesive layer (Invention 4).

[0014] In the above inventions (Inventions 1 to 4), when interfacial ablation is caused in the interfacial ablation layer, it is preferable that blisters are formed at the positions where the interfacial ablation occurs (Invention 5).

[0015] In the above inventions (Inventions 1 to 5), it is preferable that the interfacial ablation locally generated in the interfacial ablation layer is used to selectively separate any one of a plurality of workpieces held on the surface of the interfacial ablation layer opposite the substrate from the interfacial ablation layer (Invention 6).

[0016] In the above invention (Invention 6), it is preferable that the small workpieces are obtained by singulating a workpiece held on the surface of the interface ablation layer opposite the substrate on that surface (Invention 7). [Effects of the Invention]

[0017] The workpiece handling sheet according to the present invention is less likely to cause chip scattering even when dicing is performed. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described. The workpiece handling sheet according to this embodiment comprises a substrate and an interface ablation layer laminated on one side of the substrate.

[0019] In the workpiece handling sheet according to this embodiment, the interface ablation layer can hold the workpiece, i.e., the workpiece handling sheet according to this embodiment can hold the workpiece stacked on the surface of the interface ablation layer opposite the substrate in that state.

[0020] Although the specific manner of holding is not limited, a preferred example is that the interface ablation layer holds the workpiece by exerting adhesiveness to the workpiece. In this case, as described below, the interface ablation layer preferably contains an adhesive as one of its constituent components, i.e., is an adhesive layer.

[0021] Furthermore, the interfacial ablation layer in this embodiment undergoes interfacial ablation by irradiation with laser light. That is, the interfacial ablation layer undergoes local interfacial ablation in the region irradiated with the laser light. The laser light is not particularly limited as long as it can cause interfacial ablation, and may be laser light having a wavelength in the ultraviolet, visible, or infrared region, with laser light having a wavelength in the ultraviolet region being preferred.

[0022] In this specification, interfacial ablation refers to the phenomenon in which some of the components constituting the interfacial ablation layer are evaporated or volatilized by the energy of the laser light, and the resulting gas accumulates at the interface between the interfacial ablation layer and the substrate, forming voids (blisters). In this case, the shape of the interfacial ablation layer is changed by the blisters, and small pieces of the workpiece peel off from the interfacial ablation layer, resulting in separation of the small pieces of the workpiece.

[0023] The interfacial ablation layer in this embodiment contains an ultraviolet absorber. The presence of the ultraviolet absorber in the interfacial ablation layer improves the efficiency with which the interfacial ablation layer receives energy from the laser light. This effectively generates interfacial ablation, enabling the held workpiece to be successfully separated from the interfacial ablation layer. In particular, the amount of laser light irradiation required to sufficiently separate the workpiece is reduced, reducing the operating cost of the laser light irradiation device, and making it easier to successfully separate only the targeted workpiece, improving accuracy. Furthermore, it is also possible to prevent damage to the device, etc., due to excessive laser light irradiation.

[0024] Furthermore, in the workpiece handling sheet according to this embodiment, when the thickness of the interface ablation layer is T (μm) and the loop tack value of the surface of the interface ablation layer opposite to the substrate to the mirror surface of the silicon wafer is L (mN / 25 mm), the following formula (1) can be obtained: Evaluation value = L / T 2 …(1) The evaluation value calculated from is 10 or more.

[0025] The workpiece handling sheet according to this embodiment satisfies the above-described evaluation value conditions, and therefore, even when dicing a workpiece (especially dicing using a rotating circular blade) on the workpiece handling sheet, chips resulting from the workpiece being separated into individual pieces are effectively prevented from scattering due to the impact of dicing. From this perspective, the evaluation value is preferably 15 or more, more preferably 20 or more, and even more preferably 30 or more. Meanwhile, the upper limit of the evaluation value is not particularly limited and may be, for example, 200 or less, particularly 100 or less, or even 50 or less. Details of the method for measuring the loop tack value are as described in the test examples below.

[0026] 1.Interface ablation layer The specific configuration and composition of the interface ablation layer in this embodiment are not particularly limited, as long as it is capable of holding a small workpiece, has the property of interfacial ablation by irradiation with laser light, and contains an ultraviolet absorber.

[0027] From the viewpoint of easily exhibiting the property of being able to hold small workpieces well, the interfacial ablation layer preferably contains an adhesive as one of its constituent components, as described above. When the interfacial ablation layer contains an adhesive, the interfacial ablation layer is preferably made of an adhesive composition containing an ultraviolet absorber.

[0028] (1) UV absorbers The type of the ultraviolet absorber in this embodiment is not particularly limited. The ultraviolet absorber in this embodiment may be an organic compound or an inorganic compound, but is preferably an organic compound from the viewpoint of easily generating good interfacial ablation.

[0029] When the ultraviolet absorber is an organic compound, preferred examples of the ultraviolet absorber include compounds such as hydroxyphenyltriazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, benzoxazinone-based ultraviolet absorbers, phenyl salicylate-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, nickel complex salt-based ultraviolet absorbers, hydroquinone-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, malonic acid ester-based ultraviolet absorbers, and oxalic acid-based ultraviolet absorbers. These may be used alone or in combination of two or more.

[0030] Among the above-mentioned ultraviolet absorbers, it is preferable to use at least one of a hydroxyphenyltriazine-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and a benzotriazole-based ultraviolet absorber, from the viewpoint of having good absorption properties at the third harmonic wave (355 nm) of YAG and easily causing good interfacial ablation, and it is particularly preferable to use a hydroxyphenyltriazine-based ultraviolet absorber.

[0031] Examples of the hydroxyphenyltriazine ultraviolet absorber include 2-[4-(octyl-2-methylethanoate)oxy-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)]-1,3,5-triazine, 2-[4-(2-hydroxy-3-dodecyloxy-propyl)oxy-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-(2-hydroxy-3- tridecyloxy-propyl)oxy-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-(2-hydroxy-3-(2'-ethyl)hexyloxy]-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)-1,3,5-triazine, 2, Examples include 4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1,3-5-triazine, 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine, and tris[2,4,6-[2-{4-(octyl-2-methylethanoate)oxy-2-hydroxyphenyl}]-1,3,5-triazine. These may be used alone or in combination of two or more. Among these, it is preferable to use at least one of tris[2,4,6-[2-{4-(octyl-2-methylethanoate)oxy-2-hydroxyphenyl}]-1,3,5-triazine and 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine.

[0032] Furthermore, when the ultraviolet absorber is an organic compound, the ultraviolet absorber is preferably a compound having one or more heterocycles as a feature of its chemical structure, in which case the number of heterocycles is preferably four or less, and particularly preferably one.

[0033] As another feature of the chemical structure, it is also preferable that the ultraviolet absorber in the present embodiment has at least one of a carbon ring and a heterocycle, and that all of the carbon rings and heterocycles contained in the ultraviolet absorber are monocyclic.

[0034] As a further feature of the chemical structure, the ultraviolet absorber in this embodiment is also preferably a compound having multiple aromatic rings. In this case, the number of aromatic rings is preferably 2 or more. Furthermore, the number of aromatic rings is preferably 6 or less, and particularly preferably 3 or less.

[0035] In the above-mentioned chemical structure characteristics, each heterocycle preferably has at least one element selected from nitrogen, oxygen, phosphorus, sulfur, silicon, and selenium as an element other than carbon constituting the heterocycle, and particularly preferably has at least one element selected from nitrogen, oxygen, phosphorus, and sulfur.In addition, the number of atoms constituting the ring structure of the heterocycle is not particularly limited, and is, for example, 3 or more and 9 or less, particularly preferably 5 or more and 6 or less.Specific examples of preferred heterocycles include triazine, benzotriazole, thiophene, pyrrole, imidazole, pyridine, pyrazine, etc.

[0036] In addition, in the above-mentioned characteristics of the chemical structure, preferred examples of the aromatic ring include benzene, naphthalene, anthracene, biphenyl, and triphenyl.

[0037] An example of an ultraviolet absorber having the above-described chemical structural characteristics is an ultraviolet absorber having the following structure: tris[2,4,6-[2-{4-(octyl-2-methylethanoate)oxy-2-hydroxyphenyl}]-1,3,5-triazine.

[0038] [ka]

[0039] In this embodiment, the content of the ultraviolet absorber in the interface ablation layer is preferably 1% by mass or more, more preferably 2% by mass or more, particularly preferably 3% by mass or more, and even more preferably 4% by mass or more. When the content of the ultraviolet absorber is 1% by mass or more, the interface ablation layer efficiently absorbs laser light, thereby facilitating good interface ablation. Furthermore, in this embodiment, the content of the ultraviolet absorber in the interface ablation layer is preferably 30% by mass or less, more preferably 20% by mass or less, particularly preferably 10% by mass or less, and even more preferably 7% by mass or less. When the content of the ultraviolet absorber is 30% by mass or less, the viscosity of the material for forming the interface ablation layer becomes appropriate, making it easier to ensure good film-forming properties.

[0040] (2) Adhesive As described above, the interfacial ablation layer in this embodiment may contain a pressure-sensitive adhesive in addition to the ultraviolet absorber. In this case, the interfacial ablation layer is preferably formed from a pressure-sensitive adhesive composition containing the ultraviolet absorber.

[0041] The adhesive is not particularly limited as long as it can exert sufficient holding power (adhesive strength) on the adherend, such as a small workpiece. Examples of the adhesive include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among these, it is preferable to use acrylic adhesives because they can easily exert the desired adhesive strength.

[0042] Furthermore, although the adhesive may be an adhesive that does not have active energy ray curability, it is preferably an adhesive that has active energy ray curability (hereinafter, may be referred to as an "active energy ray curable adhesive.") When the interface ablation layer is made of an active energy ray curable adhesive, the interface ablation layer can be cured by irradiation with active energy rays, and the adhesive strength of the work handling sheet to the adherend can be easily reduced.

[0043] In particular, by combining the reduction in adhesive strength by irradiation with active energy rays with the above-mentioned interfacial ablation, separation of the workpiece from the work handling sheet becomes easier. That is, by reducing adhesion by irradiation with active energy rays before or simultaneously with the above-mentioned interfacial ablation, separation of the workpiece from the work handling sheet according to this embodiment can be more reliably performed. In addition, it is possible to further reduce the amount of laser light irradiation required to sufficiently separate the workpiece.

[0044] The active energy ray-curable adhesive may be one whose main component is a polymer having active energy ray curability, or one whose main component is a mixture of a non-active energy ray-curable polymer (a polymer not having active energy ray curability) and a monomer and / or oligomer having at least one or more active energy ray-curable groups. In addition, the active energy ray-curable adhesive may be a mixture of a polymer having active energy ray curability and a monomer and / or oligomer having at least one or more active energy ray-curable groups.

[0045] The active energy ray-curable polymer is preferably a (meth)acrylic acid ester (co)polymer (hereinafter sometimes referred to as "active energy ray-curable polymer") having an energy ray-curable functional group (active energy ray-curable group) introduced into its side chain. This active energy ray-curable polymer 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 bonded to the functional group. In this specification, "(meth)acrylic acid ester" means both an acrylic acid ester and a methacrylic acid ester. The same applies to other similar terms. Furthermore, "polymer" also includes the concept of "copolymer."

[0046] The acrylic copolymer (a1) 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 a derivative thereof.

[0047] The functional group-containing monomer as a constituent unit of the acrylic copolymer (a1) 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.

[0048] Examples of hydroxy 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 may be used alone or in combination of two or more.

[0049] Examples of the carboxy group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, etc. These may be used alone or in combination of two or more.

[0050] Examples of the amino group-containing monomer or 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.

[0051] As the (meth)acrylic acid ester monomer constituting the acrylic copolymer (a1), in addition to alkyl (meth)acrylates in which the alkyl group has 1 to 20 carbon atoms, for example, monomers having an alicyclic structure in the molecule (alicyclic structure-containing monomers) are preferably used.

[0052] As the alkyl(meth)acrylate, alkyl(meth)acrylates in which the alkyl group has 1 to 18 carbon atoms, such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, etc., are particularly preferred. These may be used alone or in combination of two or more.

[0053] Preferred examples of the alicyclic structure-containing monomer include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0054] The acrylic copolymer (a1) contains the structural units derived from the functional group-containing monomer in a proportion of preferably 1% by mass or more, particularly preferably 5% by mass or more, and even more preferably 10% by mass or more. The acrylic copolymer (a1) also contains the structural units derived from the functional group-containing monomer in a proportion of preferably 35% by mass or less, particularly preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0055] Furthermore, the acrylic copolymer (a1) contains structural units derived from (meth)acrylic acid ester monomers or their derivatives in a proportion of preferably 50% by mass or more, particularly preferably 60% by mass or more, and even more preferably 70% by mass or more. The acrylic copolymer (a1) also contains structural units derived from (meth)acrylic acid ester monomers or their derivatives in a proportion of preferably 99% by mass or less, particularly preferably 95% by mass or less, and even more preferably 90% by mass or less.

[0056] The acrylic copolymer (a1) can be obtained by copolymerizing the functional group-containing monomers described above with (meth)acrylic acid ester monomers or derivatives thereof in a conventional manner. In addition to these monomers, dimethylacrylamide, vinyl formate, vinyl acetate, styrene, etc. may also be copolymerized.

[0057] An active energy ray-curable polymer can be obtained by reacting the acrylic copolymer (a1) having the functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group of the acrylic copolymer (a1).

[0058] The functional group of the unsaturated group-containing compound (a2) can be appropriately selected depending on the type of functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, when the functional group of the acrylic copolymer (a1) is a hydroxy 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, and when 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 carboxy group, or an aziridinyl group.

[0059] The 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 in one molecule. Specific examples of such unsaturated group-containing compounds (a2) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate; acryloyl monoisocyanate compounds obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; acryloyl monoisocyanate compounds obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and 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.

[0060] The unsaturated group-containing compound (a2) is used in an amount of preferably 50 mol% or more, particularly preferably 60 mol% or more, and even more preferably 70 mol% or more, based on the number of moles of the functional group-containing monomer in the acrylic copolymer (a1). The unsaturated group-containing compound (a2) is used in an amount of preferably 95 mol% or less, particularly preferably 93 mol% or less, and even more preferably 90 mol% or less, based on the number of moles of the functional group-containing monomer in the acrylic copolymer (a1).

[0061] 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 the functional groups of the acrylic copolymer (a1) and 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), and the unsaturated groups are introduced into the side chains of the acrylic copolymer (a1), thereby obtaining an active energy radiation-curable polymer.

[0062] The weight average molecular weight (Mw) of the active energy radiation-curable polymer thus obtained is preferably 10,000 or more, particularly preferably 50,000 or more, and even more preferably 100,000 or more. The weight average molecular weight (Mw) is preferably 3,000,000 or less, particularly preferably 2,000,000 or less, and even more preferably 1,500,000 or less. The weight average molecular weight (Mw) in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0063] Even when the active energy ray-curable adhesive contains, as its main component, a polymer having active energy ray curability, such as an active energy ray-curable polymer, the active energy ray-curable adhesive may further contain an energy ray-curable monomer and / or oligomer.

[0064] As the active energy ray-curable monomer and / or oligomer, for example, an ester of a polyhydric alcohol and (meth)acrylic acid can be used.

[0065] Examples of such active energy ray-curable monomers and / or oligomers 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 dimethyloltricyclodecane di(meth)acrylate; polyester oligo(meth)acrylate; polyurethane oligo(meth)acrylate; and the like.

[0066] The adhesive composition for forming the interface ablation layer preferably contains a crosslinking agent. The use of a crosslinking agent is particularly preferred from the viewpoint of easily adjusting the storage modulus of the interface ablation layer to a desired range. The crosslinking agent may be a polyfunctional compound reactive with the reactive functional groups of the active energy radiation-curable polymer or the like. 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.

[0067] The amount of the crosslinking agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 4 parts by mass or more, relative to 100 parts by mass of the active energy ray-curable polymer. The amount of the crosslinking agent is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 17 parts by mass or less, relative to 100 parts by mass of the active energy ray-curable polymer.

[0068] The adhesive composition for forming the interfacial ablation layer preferably contains a photopolymerization initiator. When the interfacial ablation layer in this embodiment contains a photopolymerization initiator, the curing reaction of the active energy ray-curable polymer can be easily and efficiently promoted.

[0069] Specific examples of the photopolymerization initiator 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-diphenylethan-1-one, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexane, 1-methyl-2-phenylpropan-1-one ... Hexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-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, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl) yl)-9H-carbazol-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-dimethylthioxanthone, 2,4-diethylthioxanthone Examples of such an ester include oxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, etc. These may be used alone or in combination of two or more.

[0070] The amount of the photopolymerization initiator 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, relative to 100 parts by mass of the active energy ray-curable polymer. The amount of the photopolymerization initiator 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, relative to 100 parts by mass of the active energy ray-curable polymer. By using the amount of the photopolymerization initiator within the above range, it becomes easier to effectively cure the interface ablation layer.

[0071] In addition to the above-mentioned components, the adhesive composition for forming the interface ablation layer may contain other additives, such as tackifiers, coloring materials such as dyes and pigments, flame retardants, fillers, and antistatic agents.

[0072] (3) Physical properties of the interface ablation layer In this embodiment, the thickness T of the interface ablation layer is preferably 3 μm or less, and particularly preferably 5 μm or less. When the thickness T of the interface ablation layer is 3 μm or less, it becomes easier to achieve the above-mentioned evaluation value. On the other hand, the thickness T of the interface ablation layer is preferably 17 μm or more, and particularly preferably 15 μm or more. When the thickness T of the interface ablation layer is 17 μm or more, it becomes easier to hold the workpiece well.

[0073] 2. Base material The substrate 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 to exhibit the desired functions, it is preferable that the substrate be made of a resin. When the substrate is made of a resin, examples of the resin include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin-based resins such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymer, and norbornene resin; ethylene-vinyl acetate copolymer; ethylene-based copolymer resins such as ethylene-(meth)acrylic acid copolymer, ethylene-methyl(meth)acrylate copolymer, and other ethylene-(meth)acrylic acid ester copolymers; polyvinyl chloride-based resins such as polyvinyl chloride copolymers; (meth)acrylic acid ester copolymers; polyurethane; polyimide; polystyrene; polycarbonate; and fluororesins. The resin constituting the substrate may also be a crosslinked version of the above-mentioned resin or a modified version of the above-mentioned resin, such as an ionomer. The substrate may be a single-layer film made of the above-mentioned resin, or a laminate film made of a plurality of such films. In this laminate film, the materials constituting the layers may be the same or different.

[0074] In this embodiment, the surface of the substrate may be subjected to a surface treatment such as an oxidation method or a roughening method, or a primer treatment, in order to improve adhesion to the interfacial ablation layer. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment. Examples of the roughening method include sandblasting and thermal spray treatment.

[0075] The substrate in this embodiment may contain various additives such as a colorant, a flame retardant, a plasticizer, an antistatic agent, a lubricant, a filler, etc. Furthermore, when the interface ablation layer contains a material that is cured by active energy rays, the substrate preferably has transparency to active energy rays.

[0076] The method for producing the substrate in this embodiment is not particularly limited as long as it is a method for producing a substrate from a resin. For example, the substrate can be produced by molding a resin into a sheet shape by a melt extrusion method such as a T-die method or a round die method, a calendar method, or a solution method such as a dry method or a wet method.

[0077] In this embodiment, the thickness of the substrate 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 substrate 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. By having the thickness of the substrate within the above range, the workpiece handling sheet has a predetermined balance of rigidity and flexibility, making it easier to handle small workpieces.

[0078] 3.Release sheet In this embodiment, when the interfacial ablation layer contains an adhesive as one of its constituent components, a release sheet may be laminated on the surface opposite the substrate in order to protect that surface until it is attached to a small piece of work.

[0079] The release sheet may have any configuration, and may be, for example, a plastic film that has been subjected to a release treatment using a release agent or the like. Specific examples of such plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. Silicone-based, fluorine-based, and long-chain alkyl-based release agents can be used, and among these, silicone-based ones are preferred because they are inexpensive and provide stable performance.

[0080] There are no particular limitations on the thickness of the release sheet, and it may be, for example, 20 μm or more and 250 μm or less.

[0081] 4. Other configurations In the workpiece handling sheet according to this embodiment, an adhesive layer may be laminated on the surface of the interface ablation layer opposite the substrate. In this sheet, a workpiece is attached to the surface of the adhesive layer opposite the interface ablation layer, and the adhesive layer is diced together with the workpiece to obtain a workpiece having a singulated adhesive layer laminated thereon. The singulated adhesive layer allows the chip to be easily fixed to the object on which the workpiece is to be mounted. The material constituting the adhesive layer described above is preferably one containing a thermoplastic resin and a low-molecular-weight thermosetting adhesive component, or one containing a B-stage (semi-cured) thermosetting adhesive component.

[0082] Furthermore, in the workpiece handling sheet according to this embodiment, a protective film forming layer may be laminated on the surface of the interface ablation layer opposite the substrate. In such a sheet, a workpiece is attached to the surface of the protective film forming layer opposite the interface ablation layer, and the protective film forming layer is diced together with the workpiece to obtain individualized workpiece pieces on which the protective film forming layer is laminated. It is preferable that the workpiece has a circuit formed on one side. In this case, the protective film forming layer is typically laminated on the surface opposite the surface on which the circuit is formed. The individualized protective film forming layer can be cured at a predetermined timing to form a protective film with sufficient durability on the workpiece. The protective film forming layer is preferably made of an uncured curable adhesive.

[0083] 5. Physical properties of work handling sheets In the workpiece handling sheet according to this embodiment, the loop tack value L of the surface of the interfacial ablation layer opposite the substrate relative to the mirror surface of the silicon wafer is preferably 800 mN / 25 mm or more, and particularly preferably 900 mN / 25 mm or more. A loop tack value L of 800 mN / 25 mm or more makes it easier to achieve the aforementioned evaluation value. Furthermore, the loop tack value L is preferably 2500 mN / 25 mm or less, and particularly preferably 2300 mN / 25 mm or less. A loop tack value L of 2500 mN / 25 mm or less makes it easier to prevent excessive adhesion of workpiece pieces to the interfacial ablation layer, facilitating good separation of the workpiece pieces.

[0084] 6. Manufacturing method of work handling sheet The method for manufacturing the workpiece handling sheet according to this embodiment is not particularly limited. For example, the interface ablation layer may be formed directly on the substrate, or the interface ablation layer may be formed on a process sheet and then transferred onto the substrate.

[0085] When the interface ablation layer contains a pressure-sensitive adhesive as one of its constituent components, the interface ablation layer can be formed by a known method. For example, a coating liquid containing a pressure-sensitive adhesive composition for forming the interface ablation layer and, if desired, a solvent or dispersion medium is prepared. The coating liquid is then applied to one side of the substrate or the release surface of the release sheet (hereinafter sometimes referred to as the "release surface"). The resulting coating film is then dried to form the interface ablation layer.

[0086] The coating of the coating liquid described above can be carried out by a known method, such as bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, gravure coating, etc. The properties of the coating liquid are not particularly limited as long as it can be applied, and the coating liquid may contain components for forming the interface ablation layer as a solute or as a dispersoid. Furthermore, when the interface ablation layer is formed on a release sheet, the release sheet may be peeled off as a processing material, or may protect the interface ablation layer until it is attached to the adherend.

[0087] When the adhesive composition for forming the interface ablation layer contains the above-mentioned crosslinking agent, it is preferable to change the above-mentioned drying conditions (temperature, time, etc.) or to separately perform heat treatment to promote the crosslinking reaction between the polymer component in the coating film and the crosslinking agent, thereby forming a crosslinked structure with the desired density in the interface ablation layer. Furthermore, in order to sufficiently promote the above-mentioned crosslinking reaction, after the work handling sheet is completed, it may be cured by, for example, leaving it to stand in an environment of 23°C and a relative humidity of 50% for several days.

[0088] 7.How to use the work handling sheet The workpiece handling sheet according to this embodiment can be suitably used for handling small workpieces. As described above, in the workpiece handling sheet according to this embodiment, the interface ablation layer efficiently ablates the interface when irradiated with laser light, so that the small workpieces held on the interface ablation layer can be separated toward a predetermined position with high precision.

[0089] An example of a method of using the work handling sheet of this embodiment is to selectively separate any of multiple work pieces held on the surface of the interfacial ablation layer opposite the substrate from the interfacial ablation layer by locally generating interfacial ablation in the interfacial ablation layer.

[0090] In the above-described method of use, the plurality of workpiece pieces held on the interface ablation layer are preferably obtained by singulating workpieces (materials for the workpiece pieces) held on the surface of the interface ablation layer opposite the substrate on that surface. That is, the workpiece pieces are preferably obtained by dicing the workpiece on the interface ablation layer. As described above, the workpiece handling sheet according to this embodiment can effectively prevent the scattering of workpiece pieces formed by dicing, even when dicing is performed on the sheet. Alternatively, the workpiece pieces may be formed independently of the workpiece handling sheet according to this embodiment and placed on the interface ablation layer.

[0091] In addition, when the workpiece handling sheet according to this embodiment includes the adhesive layer and the protective film forming layer described above, it is preferable to dice these layers and the workpiece on the interface ablation layer, thereby obtaining small workpiece pieces in which these layers are individually stacked.

[0092] Although the shape and size of the workpiece in this embodiment are not particularly limited, the size of the workpiece is preferably 10 μm or less in area when viewed from above. 2 It is preferable that the thickness is 100 μm or more, and particularly 100 μm 2 It is preferable that the workpiece has an area of ​​1 mm or more when viewed from above. 2 It is preferable that it is equal to or less than 0.25 mm, and particularly 0.25 mm 2It is preferable that the dimensions of the workpiece are 2 μm or less. Furthermore, when the workpiece is rectangular, the smallest side of the workpiece is preferably 2 μm or more, particularly preferably 5 μm or more, and even more preferably 10 μm or more. Furthermore, the smallest side is preferably 1 mm or less, particularly preferably 0.5 mm or less. Specific examples of the dimensions of rectangular workpieces include 2 μm x 5 μm, 10 μm x 10 μm, 0.5 mm x 0.5 mm, 1 mm x 1 mm, etc. The workpiece handling sheet according to this embodiment can handle such small workpieces well, especially small workpieces that are difficult to separate from the sheet by pushing up with a needle. On the other hand, the workpiece handling sheet according to this embodiment can handle workpieces with an area of ​​1 mm 2 Exceeding (e.g. 1 mm 2 ~2000mm 2 The workpiece handling sheet according to this embodiment can handle relatively large workpieces, such as those with a thickness of 1 to 10,000 μm (for example, 10 to 1,000 μm). Furthermore, the workpiece handling sheet according to this embodiment can perform dicing and laser lift-off well even for thin workpieces (for example, 150 μm or less) that are prone to chip scattering during dicing.

[0093] Examples of the workpiece 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 is preferably a light-emitting diode, and more 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 densely arranged has been considered. In the manufacture of such devices, the workpiece handling sheet according to this embodiment, which can handle these light-emitting diodes with high precision, is highly suitable.

[0094] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, 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. [Example]

[0095] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0096] Example 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) with active energy ray curable groups introduced into its side chains. The weight average molecular weight (Mw) of this acrylic polymer was measured using the method described above and found to be 1,000,000.

[0097] 100 parts by mass (solids content equivalent, the same applies below) of the acrylic polymer obtained above, 15 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Mitsui Chemicals, Inc., product name "Takenate D-110N") 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 5 parts by mass of tris[2,4,6-[2-{4-(octyl-2-methylethanoate)oxy-2-hydroxyphenyl}]-1,3,5-triazine (hydroxyphenyl triazine-based ultraviolet absorber, manufactured by BASF, product name "Tinuvin 477") as an ultraviolet absorber were mixed in a solvent to obtain a coating liquid of an adhesive composition.

[0098] (2) Formation of an interface ablation layer (adhesive layer) The adhesive composition coating solution obtained in step (1) was applied to the release surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031"), which was a 38 μm-thick polyethylene terephthalate film with a silicone-based release agent layer formed on one side thereof, and the resulting coating film was dried by heating. This produced a laminate consisting of a 5 μm-thick interface ablation layer formed by the dried coating film and the release sheet.

[0099] (3) Preparation of work handling sheet The surface of the laminate obtained in step (2) facing the interface ablation layer was bonded to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "T-910 WM19", thickness: 50 μm) as a substrate to obtain a work handling sheet with a release sheet attached.

[0100] Here, the weight average molecular weight (Mw) is a weight average molecular weight measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement) and converted into standard polystyrene. <Measurement conditions> Measurement equipment: Tosoh HLC-8320 GPC columns (passed in the following order): Tosoh Corporation TSK gel superH-H TSK gel super HM-H TSK gel superH2000 Measurement solvent: tetrahydrofuran ·Measurement temperature: 40℃

[0101] [Examples 2 to 5 and Comparative Examples 1 to 6] A work handling sheet was manufactured in the same manner as in Example 1, except that the amount of crosslinking agent, the type and amount of photopolymerization initiator, the amount of ultraviolet absorber, and the thickness of the interface ablation layer (adhesive layer) were changed as shown in Table 1.

[0102] Comparative Example 7 (1) Preparation of adhesive composition 72.8 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of butyl acrylate, 7 parts by mass of 2-hydroxyethyl acrylate, and 0.2 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 (meth)acrylic acid ester polymer was measured by the above-mentioned method and found to be 700,000.

[0103] 100 parts by mass (solid content equivalent, same below) of the acrylic polymer obtained above, 8.75 parts by mass of an isocyanurate trimer of 1,6-hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate HX") as a crosslinking agent, and 32 parts by mass of tris[2,4,6-[2-{4-(octyl-2-methylethanoate)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 liquid of an adhesive composition.

[0104] (2) Formation of an interface ablation layer (adhesive layer) The adhesive composition coating solution obtained in step (1) was applied to the release surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031"), which was a 38 μm-thick polyethylene terephthalate film with a silicone-based release agent layer formed on one side thereof, and the resulting coating film was dried by heating. This produced a laminate consisting of a 10 μm-thick interface ablation layer formed by the dried coating film and the release sheet.

[0105] (3) Preparation of work handling sheet The surface of the laminate obtained in step (2) facing the interface ablation layer was bonded to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "T-910 WM19", thickness: 50 μm) as a substrate to obtain a work handling sheet with a release sheet attached.

[0106] Comparative Example 8 A work handling sheet was produced in the same manner as in Comparative Example 7, except that the blending amount of the ultraviolet absorber was changed as shown in Table 1.

[0107] [Test Example 1] (Measurement of Loop Tack Value) The workpiece handling sheets prepared in the Examples and Comparative Examples were cut into 25 mm x 280 mm test pieces. The release sheet was then peeled off from the test pieces, with the exposed interface ablation layer (adhesive layer) facing outward, and the substrate surfaces of both ends were brought into contact with each other to form a loop. The loop-shaped test piece was then suspended by clamping both ends between the upper grips of a universal tensile tester (manufactured by A&D Co., Ltd., product name "RTG-1225").

[0108] On the other hand, a silicon wafer was placed horizontally in the lower grip of the tensile tester using a PVC plate jig. The lower grip was then moved so that the distance from the upper grip to the silicon wafer was 120 mm, and this was used as the reference position.

[0109] The lower grip was then raised 80 mm at a speed of 300 mm / min, bringing the interfacial ablation layer of the test piece into contact with the mirror surface of the silicon wafer. After remaining in contact for 15 seconds, the lower grip was lowered at a speed of 300 mm / min, and the test piece and the silicon wafer were peeled apart. The maximum peel strength was measured and recorded as the loop tack value (mN / 25 mm). The results are shown in Table 1. All of the above loop tack tests were conducted in an environment of 23°C and 50% RH.

[0110] Furthermore, the loop tack value measured as described above was defined as L (mN / 25 mm) and the thickness of the interface ablation layer was defined as T (μm), and the evaluation value was calculated using the following formula (1). The results are shown in Table 1. Evaluation value = L / T 2 …(1)

[0111] [Test Example 2] (Evaluation of dicing) The release sheet was peeled off from the workpiece handling sheets manufactured in the examples and comparative examples to expose the interface ablation layer (adhesive layer). Then, silicon chips (150 μm thick) pre-cut into individual pieces measuring 20 mm × 20 mm were attached to the exposed surface of the interface ablation layer of the workpiece handling sheet.

[0112] One hour after attachment, the silicon chip was diced on the work handling sheet using a dicing device (manufactured by Disco Corporation, product name "DFD6362") under the following dicing conditions, thereby further dividing it into individual chips of 0.3 mm x 0.3 mm.

[0113] <Dicing conditions> Dicing machine: Disco DFD-6362 Blade: Disco NBC-2H 2050 27HECC Blade width: 0.025~0.030mm Blade exposure: 0.640~0.760mm Blade rotation speed: 35,000 rpm ·Cutting speed: 20mm / sec Cutting depth: 20 μm from the adhesive layer side of the workpiece processing sheet to the base material ·Flowing water supply amount: 1.0L / min ·Running water temperature: room temperature Cut size: 0.3mm x 0.3mm

[0114] After the dicing, the number of chips remaining on the workpiece handling sheet without scattering was counted. The dicing was evaluated based on the following criteria. The results are shown in Table 1. ○: The percentage of remaining chips was 55% or more. ×: The percentage of remaining chips was less than 55%.

[0115] [Test Example 3] (Evaluation of laser lift-off) (1) Evaluation of laser lift-off without dicing The release sheet was peeled off from the workpiece handling sheets manufactured in the examples and comparative examples to expose the interface ablation layer (adhesive layer). Then, 100 silicon chips (150 μm thick) pre-cut into individual pieces measuring 0.3 mm × 0.3 mm were attached to the exposed surface of the interface ablation layer of the workpiece handling sheet.

[0116] Then, the workpiece handling sheet is exposed to ultraviolet light (illuminance 230 mW / cm 2 , light intensity 190mJ / cm 2 ) was irradiated.

[0117] Furthermore, the surface of the work handling sheet to which the silicon chip was attached was placed downward, and a transfer tape (manufactured by Lintec Corporation, product name "D-210N") was placed opposite this surface.

[0118] Then, using a laser beam irradiation device (Keyence Corporation, product name "MD-U1000C"), each silicon chip was irradiated with laser beam from the substrate side of the workpiece handling sheet. An aluminum plate was used to provide a 0.1 mm gap between the laser beam irradiation device and the workpiece handling sheet. Laser beam spots were sequentially irradiated within a 0.1 mm x 0.1 mm area in the center of each silicon chip, leaving multiple parallel linear irradiation marks. In particular, the width of each irradiation mark was 20 μm, and the distance between each irradiation mark and its adjacent irradiation mark was 20 μm. Other irradiation conditions included a pulse frequency of 40 kHz and a scan speed of 1000 mm / s.

[0119] The number of silicon chips transferred from the workpiece handling sheet to the transfer tape by the irradiation was counted. The laser lift-off (without dicing) was then evaluated based on the following criteria. The results are shown in Table 1. ⊚: The percentage of transferred chips was 60% or more. ○: The percentage of transferred chips was 15% or more and less than 60%. ×: The percentage of transferred chips was less than 15%.

[0120] (2) Evaluation of laser lift-off after dicing In addition, for the Examples and Comparative Examples in which the dicing evaluation was "good" in Test Example 3, after dicing in Test Example 3, ultraviolet light (illuminance 230 mW / cm 2 , light intensity 190mJ / cm 2 ) was irradiated. Then, laser lift-off was performed in the same manner as in (1) above, and the number of silicon chips transferred from the work handling sheet to the transfer tape was counted. Then, based on the above criteria, the laser lift-off after dicing was evaluated. The results are shown in Table 1.

[0121] Details of the abbreviations and other information listed in Table 1 are as follows: [Acrylic polymer] 2EHA: 2-ethylhexyl acrylate HEA: 2-hydroxyethyl acrylate BA: butyl acrylate AAc: acrylic acid MOI: methacryloyloxyethyl isocyanate [Crosslinking agent] BHS8515: Trimethylolpropane-modified tolylene diisocyanate (manufactured by Toyochem Co., Ltd., product name "BHS8515") Coronate HX: Isocyanurate trimer of 1,6-hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate HX") [Photopolymerization initiator] Omnirad 184: 1-hydroxycyclohexylphenyl ketone (manufactured by IGM Resins, product name "Omnirad 184") Omnirad 379: 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholino-phenyl)butan-1-one (manufactured by IGM Resins, product name "Omnirad 379")

[0122] [Table 1]

[0123] As can be seen from Table 1, the work handling sheet obtained in the example enabled dicing to be performed well, and subsequent chip transfer by laser lift-off was also performed well. [Industrial Applicability]

[0124] The workpiece handling sheet of the present invention can be suitably used for handling semiconductor members.

Claims

1. A substrate; an interface ablation layer that is laminated on one side of the substrate, is capable of holding a small workpiece, and undergoes interface ablation when irradiated with laser light; A work handling sheet comprising: the interface ablation layer contains an ultraviolet absorber, When the thickness of the interfacial ablation layer is T (μm) and the loop tack value of the surface of the interfacial ablation layer opposite to the substrate to the mirror surface of the silicon wafer is L (mN / 25 mm), the following formula (1) can be obtained: Evaluation value = L / T ２ …(1) The evaluation value calculated from is 10 or more. A work handling sheet characterized by:

2. 2. The workpiece handling sheet according to claim 1, wherein the thickness T of the interface ablation layer is 15 μm or less.

3. 2. The workpiece handling sheet according to claim 1, wherein the loop tack value L is 800 mN / 25 mm or more and 2500 mN / 25 mm or less.

4. 2. The workpiece handling sheet according to claim 1, wherein the interface ablation layer is an adhesive layer.

5. 2. The workpiece handling sheet according to claim 1, wherein when interfacial ablation is caused in the interfacial ablation layer, blisters are formed at the positions where the interfacial ablation occurs.

6. The workpiece handling sheet described in claim 1, characterized in that it is used to selectively separate any one of multiple workpieces held on the surface of the interfacial ablation layer opposite the substrate from the interfacial ablation layer by locally generating interfacial ablation in the interfacial ablation layer.

7. The workpiece handling sheet according to claim 6, characterized in that the small workpieces are obtained by singulating a workpiece held on the surface of the interface ablation layer opposite the substrate on that surface.

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