Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/38—Pressure-sensitive adhesives [PSA]
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P95/00—Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass

Definitions

• the present invention relates to a workpiece processing sheet used for processing workpieces such as semiconductor wafers and a method for using the same.
• Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in a large diameter state, cut (diced) into chips, peeled off (picked up), and then moved to the next process, the mounting process.
• the workpieces such as semiconductor wafers are stacked on an adhesive sheet (hereinafter sometimes referred to as the "workpiece processing sheet") that has a base material and an adhesive layer, and are then processed and treated with backgrinding, dicing, cleaning, drying, expanding, picking up, mounting, etc.
• the adhesive layer may be made of an adhesive that is curable with active energy rays.
• the adhesive strength of the adhesive layer to the workpiece can be reduced by irradiating the adhesive layer with active energy rays, which makes it easier to separate (e.g. pick up) the workpiece from the adhesive sheet. Examples of such workpiece processing sheets are disclosed in Patent Documents 1 and 2.
• the adhesive layer is composed of an acrylic adhesive containing a radiation-polymerizable compound with two or more unsaturated bonds.
• the adhesive layer is composed of an acrylic adhesive containing an acrylic polymer with radiation-curable carbon-carbon double bonds in the molecule.
• the chips obtained by dicing are usually separated individually from the workpiece processing sheet by a suction collet or the like.
• the collection of chips obtained by dicing on the workpiece processing sheet is transferred to another workpiece processing sheet (pick-up sheet), and the pick-up process is then carried out on that pick-up sheet.
• the present invention was made in consideration of these circumstances, and aims to provide a new work processing sheet with excellent pick-up properties and whose adhesive strength can be easily controlled.
• the present invention provides a workpiece processing sheet including a substrate and an adhesive layer laminated on one side of the substrate, the adhesive layer being made of an adhesive formed from an adhesive composition containing an acrylic polymer, the acrylic polymer being represented by the following formula (1): (In formula (1), R1 represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms.) and the mass ratio of the benzophenyl structure in the acrylic polymer is 0.068 mass % or more (Invention 1).
• the adhesive layer is formed using an acrylic polymer having the above benzophenyl structure, and the mass ratio of the benzophenyl structure is within the above range, which makes it possible to control the adhesive strength using a new method and provides excellent pick-up properties.
• the acrylic polymer contains a monomer having a benzophenyl structure represented by the formula (1) as a monomer unit constituting the polymer (Invention 2).
• the acrylic polymer is represented by the following formula (2):
• R 2 and R 3 each represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and n represents an integer of 1 to 15.
• the compound has a structure represented by the following formula (Invention 3).
• the acrylic polymer contains a monomer having the structure shown in formula (2) as a monomer unit constituting the polymer (Invention 4).
• the workpiece processing sheet is used as at least one of a dicing sheet and a pick-up sheet (Invention 5).
• the present invention provides a method of using the workpiece processing sheet (Invention 1), which includes an attachment step of attaching the surface of the adhesive layer opposite the substrate to a workpiece, a processing step of processing the workpiece on the workpiece processing sheet, and an irradiation step of irradiating the adhesive layer with active energy rays (Invention 6).
• the present invention can provide a new workpiece processing sheet with excellent pick-up properties and whose adhesive strength can be easily controlled.
• the workpiece processing sheet according to the present embodiment includes a substrate and an adhesive layer laminated on one side of the substrate.
• the adhesive layer is made of an adhesive formed from an adhesive composition containing an acrylic polymer.
• the acrylic polymer is represented by the following formula (1): (In formula (1), R 1 represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms.) Furthermore, the mass ratio of the benzophenyl structure in the acrylic polymer is 0.068 mass % or more.
• the adhesive layer in this embodiment contains an acrylic polymer having a benzophenyl structure as shown in formula (1) above, which allows for good curing.
• the workpiece processing sheet according to this embodiment can reduce the adhesive strength to the adherend, making it easy to separate the workpiece after processing.
• the hardening of the adhesive layer described above is caused by a crosslinking reaction between acrylic polymers.
• this crosslinking reaction is a hydrogen abstraction reaction of hydrogen atoms present in the acrylic polymer by the ketone group in the benzophenyl structure shown in formula (1) above.
• this reaction proceeds at multiple sites in the acrylic polymer, a higher-order structure is formed in which the acrylic polymer is crosslinked, and as a result, the adhesive layer has a high elastic modulus.
• the following formula (3) shows an example of the hydrogen abstraction reaction.
• the following formula (3) shows a reaction occurring between any benzophenyl structure in the acrylic polymer (derived from 4-benzoylphenyl methacrylate as a constituent monomer) and any structure containing a hydrogen atom in the acrylic polymer (derived from 2-ethylhexyl acrylate as a constituent monomer).
• the ketone group in the benzophenyl structure abstracts a hydrogen atom bonded to a tertiary carbon atom in the other structure, resulting in the formation of a covalent bond between the carbon atom constituting the ketone group and the tertiary carbon atom to which the hydrogen atom was bonded.
• This hydrogen abstraction reaction is not limited to tertiary carbon atoms, but also occurs from hydrogen atoms bonded to primary or secondary carbon atoms.
• This hydrogen abstraction reaction is not limited to tertiary carbon atoms, but also occurs from hydrogen atoms bonded to primary or secondary carbon atoms.
• formula (3) the possibility of abstracting hydrogen atoms other than those surrounded by dashed lines is not excluded.
• the above-mentioned hydrogen abstraction reaction can be caused by irradiation with a specific active energy ray.
• the active energy ray include ultraviolet light and electron beams, but from the viewpoint of making the reaction occur easily and effectively, ultraviolet light is preferred, and in particular ultraviolet light (UV-C) having a wavelength of 200 to 280 nm is preferred, and in particular ultraviolet light having a wavelength of 250 to 260 nm is preferred.
• UV-C ultraviolet light
• the above-mentioned hydrogen abstraction reaction occurs by irradiation with a specific active energy ray, and as a result, the adhesive layer hardens, so that the work processing sheet according to this embodiment can reduce the adhesive force to the adherend at any time.
• the workpiece processing sheet according to this embodiment exhibits excellent pick-up properties because the mass ratio of the benzophenyl structure in the acrylic polymer is 0.068 mass% or more. This is thought to be because, with the above ratio being 0.068 mass% or more, the above crosslinking reaction between the acrylic polymers proceeds sufficiently, sufficiently reducing the adhesive force to the workpiece after processing, and as a result, the force required to pick up the workpiece is sufficiently reduced.
• the above ratio is preferably 0.68% by mass or more, and more preferably 3.4% by mass or more. Furthermore, from the viewpoint of making it easier for the adhesive layer to exhibit the desired performance, the above ratio is preferably 47.6% by mass or less, more preferably 34% by mass or less, and even more preferably 10.2% by mass or less.
• the mass ratio of the benzophenyl structure in the acrylic polymer refers to the ratio of the total mass of all benzophenyl structures (structures represented by the above formula (1)) contained in the acrylic polymer to the mass (weight average molecular weight) of the acrylic polymer.
• the ratio of the structural portion derived from the monomer having the benzophenyl structure in the acrylic polymer is preferably 0.1 mass% or more, particularly preferably 1 mass% or more, and further preferably 5 mass% or more. Moreover, this ratio is preferably 70 mass% or less, particularly preferably 50 mass% or less, and further preferably 15 mass% or less.
• the structure that provides the hydrogen atom in the hydrogen abstraction reaction is not particularly limited as long as it is a hydrogen atom present in the acrylic polymer.
• it may be a hydrogen atom bonded to any carbon atom in the acrylic polymer.
• the acrylic polymer is preferably a structure represented by the following formula (2): (In formula (2), R 2 and R 3 each represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and n represents an integer of 1 to 15.) It is preferred that the compound has a structure represented by the formula:
• the substrate in this embodiment is not particularly limited as long as it exhibits the desired function when the workpiece processing sheet is used.
• the substrate is preferably a resin film mainly made of a resin material.
• Specific examples thereof include polyolefin films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norbornene resin film; polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate; ethylene-vinyl acetate copolymer film; ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)methyl acrylate copolymer film, and other ethylene-(meth)acrylic acid ester copolymer films; polyvinyl chloride films such as polyvinyl chloride copolymer films; (meth)acrylic
• the substrate may be a laminated film in which a plurality of the above-mentioned films are laminated together.
• the materials constituting the layers may be the same or different.
• the workpiece processing sheet according to this embodiment when used as a dicing sheet, it is preferable to use a polyester film (particularly a polyethylene terephthalate film) as the substrate. Also, when the workpiece processing sheet according to this embodiment is used as a pick-up sheet, it is preferable to use a polyolefin film as the substrate.
• (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms.
• polymer also includes the concept of "copolymer.”
• the substrate may contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers.
• additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers.
• the amount of these additives contained is not particularly limited, but is preferably within a range in which the substrate exhibits the desired function.
• the surface of the substrate on which the adhesive layer is laminated may be subjected to a surface treatment such as a primer treatment, corona treatment, or plasma treatment to enhance adhesion to the adhesive layer.
• a surface treatment such as a primer treatment, corona treatment, or plasma treatment to enhance adhesion to the adhesive layer.
• the thickness of the substrate can be set appropriately depending on the method in which the workpiece processing sheet is used, but is preferably, for example, 200 ⁇ m or less, and more preferably 150 ⁇ m or less.
• the thickness of the substrate is preferably 10 ⁇ m or more, and more preferably 25 ⁇ m or more.
• the pressure-sensitive adhesive layer in the present embodiment is composed of a pressure-sensitive adhesive formed from a pressure-sensitive adhesive composition containing an acrylic polymer, and the acrylic polymer is represented by the following formula (1):
• the monomer contains a monomer having a benzophenyl structure represented by the following formula:
• R 1 represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms.
• the number of carbon atoms is preferably 1 to 14, and more preferably 1 to 10.
• a typical example of the benzophenyl structure is a case where all R 1 are hydrogen atoms.
• the benzophenyl structure may be present in any form, but from the viewpoint of ease of preparation of the acrylic polymer, it is preferable that the acrylic polymer contains a monomer having the benzophenyl structure represented by the above formula (1) as a monomer unit constituting the polymer.
• Examples of the monomer include 4-benzoylphenyl (meth)acrylate, 4-acryloyloxyethoxybenzophenone, 4-acryloyloxy-4'-methoxybenzophenone, 4-acryloyloxyethoxy-4'-methoxybenzophenone, 4-methacryloyloxyethoxybenzophenone, 4-methacryloyloxy-4'-methoxybenzophenone, 4-methacryloyloxyethoxy-4'-methoxybenzophenone, etc., and among these, 4-benzoylphenyl methacrylate is preferred. These may be used alone or in combination of two or more.
• R 4 represents an alkylene group having 1 to 18 carbon atoms, an oxygen atom, or an -NH- group.
• R 4 represents an alkylene group having 1 to 18 carbon atoms, an oxygen atom, or an -NH- group.
• the preferred ratio of the monomer having the benzophenyl structure represented by formula (1) to the monomer units constituting the acrylic copolymer is as described above.
• the acrylic copolymer in the present embodiment is represented by the following formula (2):
• R 2 and R 3 each represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and n represents an integer of 1 to 15.
• R2 is the alkyl group
• the number of carbon atoms is preferably 1 to 18, and more preferably 1 to 10.
• n is preferably 1 to 15, and more preferably 1 to 8.
• the structure represented by the above formula (2) may be present in any form, but from the viewpoint of ease of preparation of the acrylic polymer, it is preferable that the acrylic polymer contains a monomer having the structure represented by the above formula (2) as a monomer unit constituting the polymer.
• Examples of monomers having the structure shown in formula (2) above include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc., with 2-ethylhexyl acrylate being preferred. These may be used alone or in combination of two or more.
• the ratio of the monomer having the structure represented by the above formula (2) to the monomer units constituting the acrylic copolymer is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.
• the acrylic copolymer is easily crosslinked.
• the above ratio is preferably 99.9% by mass or less, more preferably 99% by mass or less, and even more preferably 95% by mass or less.
• the above ratio is 99.9% by mass or less, it becomes easier to secure other monomers that contribute to adhesion, etc., and the adhesive layer is more likely to exhibit the desired performance.
• the acrylic copolymer in this embodiment preferably contains, as a monomer unit constituting the polymer, an alkyl (meth)acrylate having an alkyl group with 1 to 20 carbon atoms, which does not fall under the monomer having the structure represented by the above formula (2).
• 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, and propyl (meth)acrylate, are particularly preferred. These may be used alone or in combination of two or more.
• the ratio of the alkyl (meth)acrylate to the monomer units constituting the acrylic copolymer is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.
• the ratio is also preferably 99.9% by mass or less, more preferably 99% by mass or less, and even more preferably 95% by mass or less.
• the acrylic copolymer in this embodiment preferably contains a functional group-containing monomer as a monomer unit constituting the polymer.
• 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.
• Hydroxy group-containing monomers include, for example, 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., which may be used alone or in combination of two or more.
• Carboxy group-containing monomers include, for example, 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.
• amino group-containing monomers or substituted amino group-containing monomers include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used alone or in combination of two or more.
• the ratio of the functional group-containing monomer to the monomer units constituting the acrylic copolymer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more.
• the ratio is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.
• the acrylic copolymer in this embodiment may have a functional group (active energy ray curable group) having active energy ray curability introduced in the side chain.
• a functional group active energy ray curable group
• the crosslinking reaction caused by the active energy ray curable group can also be promoted by irradiation with active energy rays, making it easier to reduce the adhesive strength.
• the active energy ray curable group can be introduced, for example, by reacting a functional group derived from the functional group-containing monomer described above with an unsaturated group-containing compound having a functional group that bonds to the functional group.
• a photopolymerization initiator described later it is preferable to use a photopolymerization initiator described later together with the acrylic copolymer.
• the above-mentioned unsaturated group-containing compound contains at least one active energy ray-polymerizable carbon-carbon double bond in one molecule, preferably 1 to 6, and more preferably 1 to 4.
• unsaturated group-containing compounds include 2-(meth)acryloyloxyethyl isocyanate, meta-isopropenyl- ⁇ , ⁇ -dimethylbenzyl isocyanate, (meth)acryloyl 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; glycid
• the amount of the unsaturated group-containing compound is preferably 40 mol% or more, and more preferably 50 mol% or more, based on the amount of functional groups in the acrylic copolymer.
• the amount of the unsaturated group-containing compound is preferably 99 mol% or less, and more preferably 95 mol% or less, and even more preferably 90 mol% or less, based on the amount of functional groups in the acrylic copolymer.
• the acrylic polymer in this embodiment can be obtained by polymerizing the above-mentioned monomers by a conventional method.
• it can be prepared by polymerization using an emulsion polymerization method, a solution polymerization method, a suspension polymerization method, a bulk polymerization method, an aqueous solution polymerization method, etc.
• the emulsion polymerization method is preferred.
• an acrylic polymer can be prepared without substantially using an organic solvent. Therefore, the adhesive layer in this embodiment is substantially free of organic solvents.
• the work processing sheet according to this embodiment has a reduced environmental impact, and specifically, it is easy to suppress problems such as the volatilization of organic solvents during production and the migration of residual organic solvents from the adhesive layer to the surroundings during use of the work processing sheet.
• the adhesive layer is substantially free of organic solvents, which means that the content of organic solvents (especially volatile organic solvents such as methyl ethyl ketone, toluene, and ethyl acetate) in the adhesive layer is 0.3% or less, and particularly 0.1% or less.
• organic solvents especially volatile organic solvents such as methyl ethyl ketone, toluene, and ethyl acetate
• the emulsion can be obtained by radically polymerizing an emulsion containing one or more acrylic monomers, an emulsifier, and a polymerization initiator.
• the emulsifier is not particularly limited, and non-reactive emulsifiers, reactive emulsifiers, etc. can be used.
• the non-reactive emulsifiers that can be used include, for example, anionic emulsifiers such as alkylaryl sulfonates, alkyl sulfates, alkenyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkenyl ether sulfates, polyoxyethylene alkylaryl ether sulfates, alkyl sulfosuccinates, alkyl sulfosuccinate derivatives, alkyl diaryl ether disulfonates, and alkyl diaryl ether disulfonate derivatives; and nonionic emulsifiers such as polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene alkyl phenyl ethers, sorbitan higher fatty acid esters, polyoxyethylene sorbitan higher fatty acid esters, polyoxyethylene higher fatty acid esters, and glycerin higher fatty acid esters
• the reactive emulsifier for example, the "ADEKA REASOAP” series manufactured by Asahi Denka Kogyo Co., Ltd. or the “Aqualon” series manufactured by Daiichi Kogyo Seiyaku Co., Ltd. can be used.
• the use of a reactive emulsifier can further reduce contamination of the wafer.
• the acrylic polymer obtained by the above emulsion polymerization may be used alone as an adhesive composition, or other components may be added to it to form an adhesive composition.
• examples of the components are not limited as long as they do not impair the above-mentioned effects of the work processing sheet according to the embodiment, and examples of the components that can be added include crosslinking agents, active energy ray curable compounds, photopolymerization initiators, silane coupling agents, antistatic agents, tackifiers, antioxidants, light stabilizers, softeners, fillers, refractive index adjusters, thickeners, etc.
• the adhesive composition does not contain low molecular weight components, and in particular, it is preferable that it does not contain low molecular weight components as active energy ray curable compounds.
• low molecular weight components here refer to components with a molecular weight of 1000 or less, for example, and in particular components with a molecular weight of 800 or less.
• the acrylic polymer in this embodiment by a solution polymerization method carried out in an organic solvent.
• a solution polymerization method a known method can be used.
• the weight average molecular weight of the acrylic polymer is preferably 100,000 to 1,200,000, more preferably 200,000 to 1,000,000, and even more preferably 300,000 to 800,000. Note that the weight average molecular weight in this specification is a value calculated in terms of standard polystyrene measured by gel permeation chromatography (GPC).
• the polymerization form of the acrylic polymer in this embodiment may be a random polymer or a block polymer.
• the thickness of the adhesive layer in this embodiment is preferably 1 ⁇ m or more, particularly preferably 3 ⁇ m or more, and even more preferably 5 ⁇ m or more.
• the thickness is also preferably 60 ⁇ m or less, particularly preferably 30 ⁇ m or less, and even more preferably 20 ⁇ m or less.
• the adhesive layer is 60 ⁇ m or less thick, it becomes easier to pick up the workpiece.
• a release sheet may be laminated on the side of the adhesive layer opposite the substrate (hereinafter sometimes referred to as the "adhesive side") in order to protect that side until it is attached to the workpiece.
• the release sheet may have any configuration, and may be, for example, a plastic film that has been treated with a release agent or the like.
• plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene.
• the release agent may be silicone-based, fluorine-based, long-chain alkyl, or rubber-based, and among these, silicone-based agents are preferred because they are inexpensive and provide stable performance.
• the thickness of the release sheet there are no particular limitations on the thickness of the release sheet, and it may be, for example, 16 ⁇ m or more and 250 ⁇ m or less.
• an adhesive layer may be laminated on the surface of the adhesive layer opposite to the substrate.
• the workpiece processing sheet according to this embodiment can be used as a dicing/die bonding sheet.
• a workpiece is attached to the surface of the adhesive layer opposite to the adhesive layer, and the adhesive layer is diced together with the workpiece to obtain a chip on which the individualized adhesive layer is laminated.
• the individualized adhesive layer makes it possible for the chip to be easily fixed to the object on which the chip is mounted.
• thermosetting adhesive component As the material constituting the above-mentioned adhesive layer, it is preferable to use one containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, one containing a B-stage (semi-cured) thermosetting adhesive component, etc.
• a protective film forming layer may be laminated on the adhesive surface of the adhesive layer.
• the workpiece processing sheet according to this embodiment can be used as a sheet for forming a protective film and dicing.
• a workpiece is attached to the surface of the protective film forming layer opposite the adhesive layer, and the protective film forming layer is diced together with the workpiece to obtain a chip on which an individualized protective film forming layer is laminated.
• the protective film forming layer is usually laminated on the surface opposite to 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 having sufficient durability on the chip.
• the protective film forming layer is preferably made of an uncured curable adhesive.
• the manufacturing method of the workpiece processing sheet according to this embodiment is not particularly limited, and it is preferably manufactured by laminating an adhesive layer on one side of a substrate.
• the adhesive layer can be laminated on one side of the substrate by a known method. For example, it is preferable to transfer the adhesive layer formed on a release sheet to one side of the substrate.
• a coating liquid containing an adhesive composition constituting the adhesive layer is prepared, and the coating liquid is applied to the release-treated surface of the release sheet (hereinafter sometimes referred to as the "release surface") using a die coater, curtain coater, spray coater, slit coater, knife coater, applicator, etc. to form a coating film, and the coating film is dried to form the adhesive layer.
• the properties of the coating liquid are not particularly limited as long as it can be applied, and it may contain components for forming the adhesive layer as a solute or as a dispersoid.
• the release sheet in this laminate may be peeled off as a process material, or it may be used to protect the adhesive surface of the adhesive layer until the work processing sheet is attached to the adherend.
• the adhesive layer may be formed directly on the substrate.
• the coating liquid for forming the adhesive layer described above is applied to one side of the substrate to form a coating film, and the coating film is dried to form the adhesive layer.
• the workpiece processing sheet according to this embodiment can be used for processing a workpiece such as a semiconductor wafer. That is, after the adhesive surface of the workpiece processing sheet according to this embodiment is attached to the workpiece, the workpiece can be processed on the workpiece processing sheet. Depending on the processing, the workpiece processing sheet according to this embodiment can be used as a back grinding sheet, a dicing sheet, an expanding sheet, a pick-up sheet, a sheet used for sorting, inspecting, rearranging, storing, shipping, transporting, etc. of the workpiece. Examples of the workpiece include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.
• the workpiece processing sheet according to this embodiment can cure the adhesive layer by irradiating it with a predetermined amount of active energy, effectively reducing the adhesive force to the adherend. Therefore, it is preferable that the workpiece processing sheet according to this embodiment is used as at least one of a dicing sheet, a pick-up sheet, and a backgrind sheet.
• One example of a preferred method of using the workpiece processing sheet according to this embodiment includes an attachment step of attaching the surface of the adhesive layer opposite the substrate to the workpiece, a processing step of processing the workpiece on the workpiece processing sheet, and an irradiation step of irradiating the adhesive layer with active energy rays.
• the specific method is not limited as long as the adhesive surface of the workpiece processing sheet according to this embodiment is attached to the workpiece.
• the subsequent processing step is carried out according to the type of processing, and a conventionally known method can be used.
• a dicing device is used to dice the work on the work processing sheet to obtain multiple semiconductor chips.
• the type of dicing here is not particularly limited, and may be, for example, blade dicing, laser dicing, stealth dicing, etc.
• the irradiation of active energy rays in the irradiation step can be carried out by a conventionally known method.
• the type of active energy rays is as described above.
• the workpiece processing sheet according to this embodiment has the adhesive layer described above, the workpiece processing sheet can be used as a dicing/die bonding sheet. Furthermore, when the workpiece processing sheet according to this embodiment has the protective film forming layer described above, the workpiece processing sheet can be used as a protective film forming/dicing sheet.
• other layers may be provided between the substrate and the adhesive layer, or on the surface of the substrate opposite the adhesive layer.
• Example 1 (1) Preparation of adhesive composition 20 parts by mass of 2-ethylhexyl acrylate, 65 parts by mass of butyl acrylate, 4 parts by mass of methyl methacrylate, 10 parts by mass of 4-benzoylphenyl methacrylate, and 1 part by mass of acrylic acid, 1 part by mass of polyoxyethylene alkyl ether sulfate as an emulsifier, and 150 parts of distilled water were added to a four-neck flask equipped with a nitrogen gas inlet tube, a thermometer, a reflux condenser, and a stirrer, and the mixture was thoroughly stirred and heated to 70°C.
• step (2) Preparation of workpiece processing sheet
• the adhesive composition coating solution prepared in step (1) was applied to the release surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031”), which is a 38 ⁇ m thick polyethylene terephthalate film with a silicone-based release agent layer formed on one side thereof, while adjusting the gap with an applicator.
• the coating film thus obtained was dried at 100° C. for 2 minutes to form an adhesive layer with a thickness of 20 ⁇ m, and a laminate of the adhesive layer and the release sheet was obtained.
• Example 2 Except for changing the amount of n-butyl acrylate used to 74.9 parts by mass and the amount of 4-benzoylphenyl methacrylate used to 0.1 parts by mass, a workpiece processing sheet was produced in the same manner as in Example 1. The mass ratio of the benzophenyl structure in the acrylic polymer was calculated to be 0.068% by mass.
• Example 3 20 parts by mass of 2-ethylhexyl acrylate, 65 parts by mass of butyl acrylate, 4 parts by mass of methyl methacrylate, 1 part by mass of 2-hydroxyethyl acrylate, and 10 parts by mass of 4-benzoylphenyl methacrylate were polymerized by solution polymerization to obtain an acrylic copolymer.
• the mass ratio of the benzophenyl structure in the acrylic polymer was calculated to be 6.8% by mass.
• a workpiece processing sheet was produced in the same manner as in Example 1, except that the above coating liquid was used as the coating liquid for the adhesive composition of Example 3.
• Example 4 Except for changing the amount of n-butyl acrylate used to 74.9 parts by mass and the amount of 4-benzoylphenyl methacrylate used to 0.1 parts by mass, a workpiece processing sheet was produced in the same manner as in Example 3. The mass ratio of the benzophenyl structure in the acrylic polymer was calculated to be 0.068% by mass.
• Comparative Example 1 Except for changing the amount of n-butyl acrylate used to 74.95 parts by mass and the amount of 4-benzoylphenyl methacrylate used to 0.05 parts by mass, a workpiece processing sheet was produced in the same manner as in Example 1. The mass ratio of the benzophenyl structure in the acrylic polymer was calculated to be 0.034% by mass.
• dicing was performed using a dicing device (manufactured by Disco Corporation, product name "DFD-6362”) under the following dicing conditions.
• the substrate side of the workpiece processing sheet was irradiated with ultraviolet (UV) rays (illuminance: 230 mW/cm 2 , light quantity: 190 mJ/cm 2 ) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000m/12") to harden the adhesive layer.
• UV ultraviolet
• a pick-up device was used at room temperature, with a push-up speed of 5 mm/sec, a holding time of 0.1 msec, and a push-up amount of 700 ⁇ m, and the chip was pushed up using a needle.
• the pick-up property was evaluated based on the following criteria. The results are shown in Table 1. A: All five chips could be peeled off. x: At least one chip could not be peeled off.
• a universal tensile tester manufactured by Orientec, product name "Tensilon UTM-4-100" was used to peel the workpiece processing sheet from the silicon wafer at a peel speed of 300 mm/min and a peel angle of 180°, and the adhesive strength (mN/25 mm) to the silicon wafer was measured using the 180° peel method in accordance with JIS Z0237:2009. This was the adhesive strength before UV (ultraviolet) irradiation.
• the substrate side surface of the workpiece processing sheet was irradiated with ultraviolet (UV) rays (illuminance: 230 mW/cm 2 , light quantity: 190 mJ/cm 2 ) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2010”) to harden the adhesive layer.
• UV ultraviolet
• RAD-2010 ultraviolet irradiation device
• Adhesive strength change rate (adhesive strength before UV - adhesive strength after UV) / adhesive strength before UV
• the adhesive strength controllability was evaluated based on the following criteria. The results are shown in Table 1. A: The rate of change in adhesive strength was 10% or more. ⁇ : The rate of change in adhesive strength was less than 10%.
• the adhesive strength of the workpiece processing sheet obtained in the example was sufficiently reduced by irradiation with active energy rays, and the sheet showed excellent pick-up properties.
• the workpiece processing sheet of the present invention can be suitably used for processing workpieces such as semiconductor wafers.

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• Chemical & Material Sciences (AREA)
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• Adhesives Or Adhesive Processes (AREA)
• Laminated Bodies (AREA)
• Adhesive Tapes (AREA)

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• 2023
  • 2023-12-14 WO PCT/JP2023/044797 patent/WO2024176580A1/ja not_active Ceased
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  • 2023-12-19 TW TW112149449A patent/TW202436398A/zh unknown

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