Adhesive tape for laser dicing

Abstract

To provide an adhesive tape for laser dicing which has good water permeability of water jet at the time of dicing, can suppress chip scattering due to a water flow, and leaves no paste residue in divided chips at the time of picking up, in laser dicing for guiding a laser beam by water jet.SOLUTION: There is provided an adhesive tape in which a base material, and an adhesive layer and a separator film are sequentially stacked on one surface of the base material, wherein the base material is a curable resin film obtained by curing an ionizing radiation-curable composition, and has a through hole in a thickness direction, and the adhesive layer has a recess in a part in contact with the through hole of the curable resin film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an adhesive tape for laser dicing used to fix a semiconductor wafer when dicing it with a laser guided by a water jet. [Background technology]

[0002] Conventionally, a blade cutting method has been used for dicing semiconductor wafers and semiconductor-related materials, which involves cutting with a high-speed rotating dicing blade. However, the cutting resistance of the blade during cutting causes the individual chips to scatter from the adhesive tape holding them in place, resulting in chipping, cracking, and other defects, which reduces the productivity and quality of semiconductor chips.

[0003] On the other hand, various dicing methods using laser beams are being investigated, including a laser dicing method that uses a laser beam guided by a water jet. In this method, the cutting resistance from the blade does not directly affect the wafer, as in the blade cutting method, so the occurrence of defects such as chipping and cracking of the chip can be reduced. In addition, because it is guided by a water jet, the wafer is cooled efficiently, and the thermal load can be reduced.

[0004] In laser dicing, where the laser is guided by a water jet, there is a problem that the pressure from the water flow on the adhesive surface of the adhesive tape that holds the wafer in place during dicing makes it easy for the individual chips to peel off the adhesive tape. To address this, Patent Document 1 proposes a water-permeable adhesive tape that prevents peeling due to the water flow by using a substrate with water-permeable perforations in the support substrate.

[0005] However, when using nonwoven fabrics or perforated substrates as water-permeable substrates, as in Patent Document 1, the perforations may be uneven or the perforation area may not be large enough. As a result, depending on the chip size and dicing conditions, water flow may not permeate easily, and chips may fly off.

[0006] In contrast, Patent Document 2 describes that by using a mesh substrate for a water-permeable substrate, the size of the holes and the opening area can be made relatively larger than those of nonwoven fabrics or perforated substrates, resulting in stable water permeability and further reduction of chip breakage and chip defects.

[0007] However, when using mesh substrates to dice materials that are more difficult to cut than silicon wafers, such as silicon carbide (SiC) wafers used as power semiconductors, high-power laser processing is required. This can damage or cut the fibers of the mesh substrate with the laser, resulting in chip breakage. Furthermore, since mesh substrates are woven fabrics with a mesh-like structure made of fibers, the contact area between the substrate and the adhesive layer is small. As a result, the adhesion between the substrate and the adhesive layer is insufficient, and the adhesive layer can peel off the substrate due to the water jet, sometimes causing chip breakage or chip defects. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2001-316648 [Patent Document 2] Japanese Patent Publication No. 2008-117943 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] An object of the present invention is to provide an adhesive tape for laser dicing in which a laser is guided by a water jet, the water permeability of the water jet during dicing is good, chip flying due to the water flow can be suppressed, and there is no adhesive residue on the chips when picking up the individualized chips.

Means for Solving the Problems

[0010] This invention Akira is an adhesive tape used for laser dicing in which a laser is guided by a water jet Manufacturing method wherein the adhesive tape is formed by sequentially laminating a base material, an adhesive layer, and a separator film on one surface of the base material, the base material is a cured resin film formed by curing an ionizing radiation curable resin composition, and has through holes in the thickness direction, The cured resin film is a cured product obtained by addition curing an ionizing radiation-curable resin composition containing a polyfunctional polymerizable compound having two or more carbon-carbon double bonds in its molecule and a polyfunctional thiol compound by an en-thiol reaction, wherein the polyfunctional polymerizable compound is a polyfunctional allyl compound and the polyfunctional thiol compound is a polyfunctional secondary thiol compound. the adhesive layer has a recess in the adhesive layer at a portion in contact with the through holes of the cured resin film RuRe - Adhesive tape for laser dicing A method for manufacturing, A method for manufacturing adhesive tape for laser dicing, comprising at least the following steps (a) to (f). (a) A step of forming a laminate A on a temporary support film, in which an ionizing radiation-curable resin layer is laminated. (b) A step of forming a laminate B on a separator film, in which an adhesive layer is laminated. (c) A step of bonding the ionizing radiation-curable resin layer surface of laminate A and the adhesive layer surface of laminate B, and then peeling off the temporary support film to form a laminate C in which the separator film / adhesive layer / ionizing radiation-curable resin layer are sequentially laminated, (d) A step of pressing a mold (mold member) having regularly spaced protrusions on its surface that are 5 to 40 μm higher than the thickness of the ionizing radiation-curable resin layer against the surface of the laminate C that is not in contact with the adhesive layer, thereby penetrating the protrusions in the thickness direction of the ionizing radiation-curable resin layer and pushing them into the adhesive layer. (e) A step of curing the ionizing radiation-curable resin layer by irradiating it with ionizing radiation while the projection has penetrated the ionizing radiation-curable resin layer and been pushed into the adhesive layer, (f) Step of peeling off the mold to obtain an adhesive tape.

Effects of the Invention

[0011] The cured resin film, which is the base material of the adhesive tape for laser dicing of the present invention, is superior in transparency, flexibility, and adhesion compared to the conventionally used olefin-based synthetic resin film. It can be made into an adhesive tape with good adhesion between the base material and the adhesive layer and good damage resistance of the base material to laser light. Furthermore, in the cured resin film, through-holes in the thickness direction of the base material can be precisely formed at a high density by a mold (molding member). Therefore, in laser dicing where the laser is guided by a water jet, the water permeability of the water jet is good, defects such as chip flying and chip chipping during dicing can be suppressed, and it becomes possible to provide an adhesive tape for laser dicing without glue residue on the chips during pickup after dicing.

Brief Description of the Drawings

[0012] [Figure 1] It is a schematic cross-sectional view showing an embodiment of the adhesive tape for laser dicing of the present invention. [Figure 2] It is a schematic cross-sectional view showing an embodiment of the manufacturing process of the adhesive tape for laser dicing of the present invention.

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described.

[0014] The adhesive tape for laser dicing of the present invention has a base material made of a cured resin film obtained by curing an ionizing radiation-curable resin composition, an adhesive layer, and a separator film that are sequentially laminated, and the base material of the cured resin film has through holes in the thickness direction. The adhesive tape is obtained by sequentially laminating the adhesive layer and the ionizing radiation-curable resin layer on the separator film, pressing a mold (mold member) having regularly spaced protrusions on its surface that are higher than the thickness of the ionizing radiation-curable resin layer onto the surface side of the ionizing radiation-curable resin layer, irradiating the surface with ionizing radiation while the protrusions of the mold penetrate the ionizing radiation-curable resin layer and are pushed into the adhesive layer, curing the ionizing radiation-curable resin layer, and then peeling off the mold, thereby obtaining an adhesive tape with a cured resin film base material in which fine through holes are formed at high density and with high precision. At this time, by pressing the protrusions of the mold from the ionizing radiation-curable resin layer side to the adhesive layer, a recess is created in the adhesive layer, and a portion of the ionizing radiation-curable resin composition before curing enters this recess, resulting in a strong adhesion between the adhesive layer and the cured resin film after curing due to the anchoring effect.

[0015] (base material) The substrate constituting the adhesive tape of the present invention is a cured resin film obtained by curing an ionizing radiation-curable resin layer. The ionizing radiation-curable resin composition used for the ionizing radiation-curable resin layer is a composition containing a polyfunctional polymerizable compound having two or more carbon-carbon double bonds in its molecule that are ionizing radiation polymerizable. In particular, an ionizing radiation-curable resin composition containing the polyfunctional polymerizable compound and a polyfunctional thiol compound that yields an addition cured product by an ene-thiol reaction is preferred. The ene-thiol reaction has high curing sensitivity and curability, and is less susceptible to oxygen inhibition in radical curing, resulting in excellent productivity. Furthermore, the addition cured product obtained by the ene-thiol reaction can be homogeneous, highly transparent, flexible, and adhesive, and also has excellent mechanical strength. Compared to synthetic resin films such as polyolefins used as substrates for conventional dicing adhesive tapes, the cured resin film made from this cured product has superior adhesion to the adhesive layer, resistance to damage by laser light, and expandability. Furthermore, because it has excellent mechanical strength, the pore density of through holes can be increased, making it suitable as a substrate for the laser dicing adhesive tape of the present invention. The enthiol reaction is a reaction in which radicals are generated on a mercapto group due to irradiation with ionizing radiation, and these radicals add the mercapto group to a carbon-carbon double bond.

[0016] Examples of polyfunctional polymerizable compounds include polyfunctional (meth)acrylate compounds, polyfunctional allyl compounds, and polyfunctional vinyl compounds. Examples of polyfunctional (meth)acrylate compounds include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, and ethylene oxide-added ditrimethylolpropane tetra(meth)acrylate. Examples include polyfunctional (meth)acrylates such as tri(acryloyloxyethyl) isocyanurate, tri(methacryloyloxyethyl) isocyanurate, alkylene oxide-added tri(acryloyloxyethyl) isocyanurate, alkylene oxide-added tri(methacryloyloxyethyl) isocyanurate, and polyfunctional (meth)acryloyl group-containing isocyanurate; and polyfunctional urethane (meth)acrylates obtained by the reaction of polyfunctional isocyanates such as tolylene diisocyanate, isophorone diisocyanate, and xylylene diisocyanate with hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate.

[0017] Examples of polyfunctional allyl compounds include polyfunctional allyl ethers such as ethylene glycol diallyl ether, diethylene glycol diallyl ether, propylene glycol diallyl ether, butylene glycol diallyl ether, hexanediol diallyl ether, trimethylolpropane trialyl ether, pentaerythritol tetraallyl ether, dipentaerythritol pentaallyl ether, dipentaerythritol hexaallyl ether, ethylene oxide-added trimethylolpropane trialyl ether, and ethylene oxide-added ditrimethylolpropane tetraallyl ether; polyfunctional allyl esters such as diallyl oxalate, diallyl malonate, diallyl succinate, diallyl glutarate, diallyl adipate, diallyl phthalate, triallyl trimesinate, triallyl trimellitate, and tetraallyl pyromellitate; and polyfunctional allyl group-containing isocyanurates such as triallyl isocyanurate.

[0018] Examples of polyfunctional vinyl compounds include polyfunctional vinyl ethers such as ethylene glycol divinyl ether, diethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, trimethylolpropane trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexanyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, and ethylene oxide-added ditrimethylolpropane tetravinyl ether; and polyfunctional vinyl esters such as divinyl oxalate, divinyl malonate, divinyl succinate, divinyl glutarate, divinyl adipate, divinyl phthalate, trivinyl trimesinate, trivinyl trimellitate, and tetravinyl pyromellitate.

[0019] These polyfunctional polymerizable compounds can be used individually or in combination of two or more to obtain ionizing radiation-curable resin compositions. Among the polyfunctional polymerizable compounds, polyfunctional urethane (meth)acrylates are preferred to produce flexible cured resin films. Furthermore, in the case of addition cured products from the en-thiol reaction, polyfunctional allyl compounds are preferred because they tend to produce homogeneous cured products. Among the polyfunctional allyl compounds, triallyl isocyanurate is more preferred from the viewpoint of improving mechanical properties.

[0020] The polyfunctional thiol compounds used as cured products in the ene-thiol reaction are compounds having two or more mercapto groups (SH groups) in their molecule, such as trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), and tetraethylene glycol bis(3-mercaptopropionate). Examples include propyl From the viewpoint of improving properties such as adhesion and flexibility of the cured product obtained by the en-thiol reaction, it is more preferable to use polyfunctional secondary thiol compounds such as pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinan-2,4,6-trione, and trimethylolpropanetris(3-mercaptobutyrate).

[0021] When forming a cured product of the ene-thiol reaction, the proportions of the polyfunctional polymerizable compound and the polyfunctional thiol compound in the ionizing radiation-curable resin composition are preferably such that the molar ratio of the carbon-carbon double bond group of the polyfunctional polymerizable compound to the mercapto group of the polyfunctional thiol compound is in the range of 40:60 to 60:40, and more preferably in the range of 45:55 to 55:45, in order to ensure that the cured resin film has homogeneous properties.

[0022] Ionizing radiation-curable resin compositions are typically liquid resin compositions that have good conformability to the protrusion shape of a mold when forming through holes in a mold. However, from the viewpoint of lamination with the adhesive layer, the viscosity of the ionizing radiation-curable resin composition is preferably in the range of 1,000 to 500,000 mPa·s, and more preferably in the range of 5,000 to 100,000 mPa·s.

[0023] Synthetic resins such as acrylic resins, urethane resins, and cellulose resins can be appropriately blended into the ionizing radiation-curable resin composition to adjust its viscosity.

[0024] In ionizing radiation-curable resin compositions, it is preferable to incorporate polymerization initiators to efficiently advance the curing reaction. As polymerization initiators, it is preferable to use ionizing radiation polymerization initiators. When ultraviolet light is used as the ionizing radiation, it is preferable to use photopolymerization initiators such as benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, and 2-benzothiazole-N,N-diethyldithiocarbamate.

[0025] The content of polymerization initiator in the ionizing radiation-curable resin composition is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass.

[0026] The ionizing radiation-curable resin composition may contain, to the extent that the effects of the present invention are obtained, various additives such as monofunctional (meth)acrylate compounds, vinyl compounds, allyl compounds, and other radical polymerizable compounds, as well as antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, leveling agents, defoamers, and viscosity modifiers, as appropriate.

[0027] The thickness of the ionizing radiation-curable resin layer is preferably in the range of 50 to 300 μm, more preferably in the range of 60 to 200 μm, and even more preferably in the range of 70 to 150 μm, from the viewpoint of through-hole formation, handling of the cured resin film, and breakage and damage resistance when using adhesive tape for dicing.

[0028] As a method for forming an ionizing radiation-curable resin layer, the ionizing radiation-curable resin composition is applied uniformly to the release layer of a temporary support film to a predetermined thickness, either as is or as a coating liquid with its viscosity adjusted by a solvent, and the solvent is dried to form the ionizing radiation-curable resin layer.

[0029] Coating methods for ionizing radiation-curable resin layers include, for example, gravure coaters, bar coaters, comma knife coaters, die coaters, and reverse coaters.

[0030] A cured resin film is obtained by irradiating an ionizing radiation-curable resin layer with ionizing radiation to cure the ionizing radiation-curable resin composition. While ultraviolet light is typically used as the ionizing radiation, visible light, electron beams, X-rays, ion beams, etc., may also be used. Suitable ultraviolet light sources include, for example, ultra-high pressure mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, carbon arc lamps, black lights, and metal halide lamps.

[0031] The cured resin film used as the base material of the adhesive tape of the present invention has holes that are through-holes in the thickness direction. The shape of the holes may be any shape as long as water can escape, and examples include circular, square, triangular, diamond-shaped, etc. Among them, circular holes are preferable in terms of ease of drilling. The arrangement of the holes is preferably such that fine holes are regularly arranged (for example, in a lattice pattern such as a square lattice or a triangular lattice) in order to stabilize the water permeability. The size of the holes (hole size) is usually 0.1 mm ,

[0033] or less, preferably 0.0004 mm 2 ~0.1 mm 2 More preferably, it is 0.001 mm 2 ~0.05 mm 2 Even more preferably, it is 0.0013 mm 2 ~0.03 mm 2 When the holes are circular, the diameter is preferably 0.022 mm to 0.35 mm, more preferably 0.035 mm to 0.25 mm, and even more preferably 0.040 mm to 0.20 mm. When the holes are square, triangular or diamond-shaped, the length of one side is preferably 0.01 mm to 0.30 mm, more preferably 0.03 mm to 0.20 mm, and even more preferably 0.04 mm to 0.18 mm. Also, the number of holes per unit area (hole density) is preferably more than 1,000,000 holes / m 2 , and more preferably 5,000,000 holes / m 2 or more.

[0032] The aperture ratio due to the through-holes of the cured resin film used as the base material is preferably about 3% to 90%, more preferably about 8% to 80%, even more preferably about 10% to 55%, and still more preferably about 15% to 50%. Thereby, the water permeability becomes good, and the peeling of the chip from the adhesive tape can be prevented. Also, the mechanical strength of the tape can be ensured, and the adhesiveness between the base material and the adhesive layer can be ensured. In this case, the aperture ratio can be calculated by the following formula from the hole size and the hole density. Aperture ratio (%) = (hole size) × (hole density) × 100

[0033] In this embodiment, as a method for perforating through holes in a cured resin film, a laminate of separator film / adhesive layer / ionizing radiation-curable resin layer is formed, and a mold (mold member) having protrusions for forming the aforementioned shape and size of holes is pressed against the surface of the ionizing radiation-curable resin layer before curing. Ionizing radiation is irradiated while the protrusions of the mold penetrate the ionizing radiation-curable resin layer and are pushed into the adhesive layer, curing the ionizing radiation-curable resin layer, and then the mold is removed, thereby forming through holes in the cured resin film. Using this method, fine through holes can be formed with higher density and precision than conventionally known perforation methods, and the water permeability of the water jet can be improved.

[0034] The material of the mold used in the above drilling method is not particularly limited, but examples include resin materials, glass materials, and other inorganic materials. Examples of resin materials include acrylic resins, styrene resins, epoxy resins, polyester resins, olefin resins, polycarbonate resins, and fluororesins. Examples of glass materials include quartz glass, high silica glass, borosilicate glass, aminosilicate glass, alkali-free glass, lead glass, barium glass, phosphate silicate glass, fluoride glass, lanthanum glass, clear crystallized glass, heat-absorbing glass, and spin-on glass. Examples of other inorganic materials include silicon, silicon carbide, sapphire, gallium nitride, and carbon.

[0035] The surface of the mold that presses against the ionizing radiation-curable resin layer has regularly spaced fine protrusions for perforating the cured resin film. The shape, size, and arrangement of these protrusions are the same as the shape, size, and arrangement of the holes in the cured resin film to be perforated. Furthermore, the height of the protrusions is 5 to 40 μm higher, more preferably 10 to 30 μm higher, and even more preferably 10 to 20 μm higher than the thickness of the ionizing radiation-curable resin layer through which they penetrate, in order to penetrate the ionizing radiation-curable resin layer and push into the adhesive layer, thereby creating indentations in the adhesive layer. As for the method of forming the protrusions, methods for manufacturing molds used in UV imprinting, which is a known technology in the semiconductor field and other areas for forming fine irregularities on a surface, can be suitably used. Examples include photolithography, electron beam lithography, interference exposure, and direct lithography using a semiconductor laser.

[0036] It is preferable to apply a release treatment to the surface of the mold having protrusions in order to improve the release properties from the cured resin film formed by the curing of the ionizing radiation-curable resin layer. As for the release treatment, silicone-based release agents and fluorine-based release agents are preferred, and fluorine-based release agents having a perfluoroalkyl group are particularly preferred. Furthermore, in order to suppress detachment from the mold surface, it is preferable that the release agent has functional groups (e.g., hydroxyl groups, carboxyl groups, etc.) that can chemically bond with the surface functional groups (e.g., hydroxyl groups, carboxyl groups, etc.) of the mold material.

[0037] (Adhesive layer) As the adhesive composition used in the adhesive layer of the laser dicing adhesive tape of the present invention, commonly used acrylic adhesives, ionizing radiation-curable adhesives, heat-expandable adhesives, etc., can be used as appropriate. Ionizing radiation-curable adhesives generally contain an acrylic adhesive and an ionizing radiation polymerizable compound, and their adhesive strength decreases when irradiated with ionizing radiation. Heat-expandable adhesives generally contain an acrylic adhesive and a foaming agent (thermal expansion agent), and their adhesive strength decreases when heated. These types of adhesives that decrease in adhesive strength can be suitably used because they facilitate the removal of chips after dicing. However, in this embodiment, since an ionizing radiation-curable resin layer and an adhesive layer are laminated and a cured resin film is obtained by irradiating with ionizing radiation, it is necessary to devise a way to prevent the adhesive strength of the ionizing radiation-curable adhesive from decreasing when irradiated with ionizing radiation to obtain the cured resin film. Therefore, it is preferable to use a heat-expandable adhesive as the type that decreases in adhesive strength.

[0038] Acrylic adhesives consist of (meth)acrylic copolymers and curing agents as essential components. (Meth)acrylic copolymers can be obtained, for example, by copolymerizing one or more alkyl (meth)acrylate esters having 4 to 18 carbon atoms in the alkyl group with one or more other copolymerizable monomers having carbon-carbon double bonds using conventional methods.

[0039] Examples of the alkyl (meth)acrylates mentioned above include n-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate.

[0040] Examples of copolymerizable monomers having a carbon-carbon double bond include acrylonitrile, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, cyclohexyl (meth)acrylate, styrene, α-methylstyrene, vinyl acetate, N-vinyl-2-pyrrolidone, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, acrylic acid, methacrylic acid, itaconic acid, and fumaric acid. Among these, monomers having functional groups that can react with the curing agent described later are used as essential components.

[0041] The weight-average molecular weight (Mw) of the (meth)acrylic copolymer is preferably 10,000 to 1,000,000, and more preferably 20,000 to 800,000. By setting the weight-average molecular weight within this range, appropriate adhesive performance can be obtained for the adhesive layer of the present invention. Note that the weight-average molecular weight is the polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0042] The curing agent is used to adjust the tackiness and cohesiveness by reacting with the functional groups of the (meth)acrylic copolymer. Examples include epoxy curing agents and isocyanate curing agents.

[0043] Examples of epoxy curing agents include epoxy compounds having two or more epoxy groups in their molecules, such as 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)toluene, 1,3-bis(N,N-diglycidylaminomethyl)benzene, and N,N,N,N′-tetraglycidyl-m-xylenediamine.

[0044] Examples of isocyanate-based curing agents include polyisocyanates having two or more isocyanate groups in their molecules, such as 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, 1,3-xylylenediisocyanate, 1,4-xylylenediisocyanate, and diphenylmethane-4,4′-diisocyanate; trimers of polyisocyanates; urethane prepolymers having isocyanate groups at their ends, obtained by reacting polyisocyanates with polyols; and polyisocyanate compounds having two or more isocyanate groups in one molecule, such as trimers of the urethane prepolymers. These curing agents may be used individually or in combination of two or more types.

[0045] The amount of curing agent added can be adjusted as appropriate according to the required adhesive strength, and is typically 0.01 to 30 parts by mass, more preferably 0.1 to 15.0 parts by mass, per 100 parts by mass of (meth)acrylic copolymer.

[0046] The ionizing radiation polymerizable compounds for the aforementioned ionizing radiation-curable adhesives are, for example, low molecular weight compounds having at least two photopolymerizable carbon-carbon double bonds within a molecule that can form a three-dimensional network upon light irradiation. Specifically, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, and oligoester acrylates are widely applicable.

[0047] In addition to the acrylate compounds mentioned above, urethane acrylate oligomers can also be used. Urethane acrylate oligomers are obtained by reacting a polyol compound such as polyester or polyether type with a polyvalent isocyanate compound (e.g., 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane 4,4-diisocyanate, etc.) to obtain a terminal isocyanate urethane prepolymer, and then reacting it with an acrylate or methacrylate having a hydroxyl group (e.g., 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, etc.).

[0048] The mixing ratio of the acrylic adhesive to the ionizing radiation polymerizable compound in the ionizing radiation-curable adhesive is 5 to 200 parts by mass, more preferably 10 to 120 parts by mass, and even more preferably 10 to 50 parts by mass of the ionizing radiation polymerizable compound per 100 parts by mass of the acrylic adhesive. By mixing within this range, the adhesive strength is appropriately reduced, and damage to the chips during pickup and adhesive residue can be suppressed. Furthermore, instead of mixing the ionizing radiation polymerizable compound with the acrylic adhesive as described above, it is also possible to make the acrylic adhesive itself an ionizing radiation polymerizable acrylic acid ester copolymer.

[0049] Furthermore, it is preferable to incorporate an ionizing radiation polymerization initiator into ionizing radiation-curable adhesives. Examples of ionizing radiation polymerization initiators include isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michlar's ketone, chlorothioxanthone, benzyl methyl ketal, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxymethylphenylpropane. By adding at least one of these to the adhesive layer, the polymerization reaction can be efficiently promoted.

[0050] The amount of ionizing radiation polymerization initiator added is usually 0.05 to 15 parts by mass, preferably 0.2 to 10 parts by mass, per 100 parts by mass of ionizing radiation curable adhesive.

[0051] The foaming agent for the aforementioned heat-expandable adhesive can be appropriately selected from known heat-expanding agents, but among them, microencapsulated foaming agents can be preferably used. Examples of such microencapsulated foaming agents include heat-expandable microspheres in which a substance that readily gasifies and expands upon heating, such as isobutane, propane, or pentane, is enclosed within an elastic shell.

[0052] The shells of thermally expandable microspheres are usually formed from thermoplastics, thermally meltable materials, or materials that rupture upon thermal expansion. Examples include vinylidene chloride-acrylonitrile copolymers, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Thermally expandable microspheres can be produced by conventionally known methods, such as coacervation and interfacial polymerization.

[0053] Commercially available products can also be used as thermally expandable microspheres. Examples of such commercially available thermal foaming agents include the (trademark) Matsumoto Microsphere F series (e.g., F-30, F-50, F80S, etc.) manufactured by Matsumoto Oil & Fat Pharmaceutical Co., Ltd.

[0054] The average particle size of thermally expandable microspheres is typically around 1 to 80 μm, preferably around 3 to 50 μm, from the standpoint of dispersibility and thin-layer formation.

[0055] Furthermore, as thermally expandable microspheres, it is preferable that they have a moderate strength that prevents them from bursting until their volume expansion ratio increases to 5 times or more, and especially to 10 times or more, in order to efficiently reduce the adhesive strength of the adhesive layer containing the adhesive agent through heat treatment.

[0056] Other thermal foaming agents used in thermally expanding adhesives include, for example, inorganic and organic foaming agents. Examples of inorganic foaming agents include ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, and azides. Examples of organic foaming agents include azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate; hydrazine compounds such as p-toluenesulfonyl hydrazide, diphenylsulfon-3,3'-disulfonyl hydrazide, 4,4'-oxybis(benzenesulfonyl hydrazide), and allylbis(sulfonyl hydrazide); semicarbazide compounds such as ρ-toluenesulfonyl semicarbazide and 4,4'-oxybis(benzenesulfonyl semicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; and N-nitroso compounds such as N,N'-dinitrosopentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosotelephthalamide. These heat foaming agents can be used individually or in combination of two or more. Furthermore, the heat foaming agent-containing adhesive composition may contain foaming aids as needed.

[0057] The amount of thermal foaming agent in a thermal expansion adhesive varies depending on the type, but is typically 10 to 200 parts by mass, preferably 20 to 125 parts by mass, and more preferably 25 to 100 parts by mass, per 100 parts by mass of acrylic adhesive. Using 10 parts by mass or more allows for an effective reduction in adhesive strength after heat treatment, while using 200 parts by mass or less suppresses cohesive failure of the adhesive layer.

[0058] The adhesive layer of the present invention may contain various additives as needed, such as antioxidants, antistatic agents, leveling agents, and defoaming agents.

[0059] The amount of adhesive layer applied should be 5-50 g / m² to ensure sufficient adhesion and retention to the substrate. 2 Approximately, more preferably 10-30 g / m 2 The amount of adhesive layer coating is 5 g / m².2 By doing so, adhesive strength and holding power can be ensured, chip peeling due to the water jet flow can be suppressed, and when the protrusions of the mold are pressed into the adhesive layer, a recess is created in the adhesive layer, improving the adhesion between the cured resin film and the adhesive layer. In addition, the coating amount of the adhesive layer is 50 g / m². 2 By doing the following, the penetration of the water jet's water flow can be ensured, and manufacturing costs can be reduced.

[0060] The present invention provides a method for forming an adhesive layer, which involves applying the adhesive composition as is, or as a coating liquid with its viscosity adjusted using a solvent, to a film substrate or a release-treated separator film to a predetermined thickness, and then drying the solvent to form the adhesive layer.

[0061] Examples of coating methods for the adhesive layer coating liquid of the present invention include gravure coaters, bar coaters, comma knife coaters, die coaters, and reverse coaters.

[0062] The adhesive strength of the adhesive tape of the present invention is preferably 1 N / 25 mm or more, and more preferably 2 N / 25 mm or more, in order to suppress chip flying during dicing. Furthermore, when using an ionizing radiation-curing adhesive or a thermal expansion adhesive, the decrease in adhesive strength after ionizing radiation irradiation or heating is preferably less than 1 N / 25 mm, and more preferably less than 0.5 N / 25 mm. Lower adhesive strength during pickup after dicing can reduce defects such as chipping of the chips. Note that the adhesive strength is the value obtained when measuring the peeling force against the silicon wafer mirror surface under the conditions of a measurement temperature of 23 ± 3 °C, a peeling angle of 180 °C, and a peeling speed of 300 mm / min.

[0063] (Temporary support film) The temporary support film is used to laminate an adhesive layer and an ionizing radiation-curable resin layer. An ionizing radiation-curable resin composition is applied to the release layer of the temporary support film, which has a release layer formed on it, to form an ionizing radiation-curable resin layer. The adhesive layer formed separately on a separator is then bonded to the ionizing radiation-curable resin layer, and the temporary support film is peeled off to obtain a laminate consisting of a separator film, an adhesive layer, and an ionizing radiation-curable resin layer.

[0064] The material of the temporary support film can be, for example, a synthetic resin such as polyethylene, polypropylene, polyethylene terephthalate, polyamide, or polyurethane, but polyethylene terephthalate film is preferred from the viewpoint of heat resistance and strength. The thickness of the temporary support film is preferably about 6 to 200 μm, and more preferably about 12 to 100 μm, from the viewpoint of handling and cost.

[0065] The release agent used for the release layer of the temporary support film can be any conventionally known release agent, such as a silicone-based release agent, a long-chain alkyl-based release agent, or a fluorine-based release agent. Among these, a silicone-based release agent is preferred as it is relatively inexpensive and provides stable release properties, and can be appropriately selected depending on the release characteristics with ionizing radiation-curable resins.

[0066] As a silicone-based release agent, for example, a thermosetting addition-type silicone-based release agent can be suitably used. A thermosetting addition-type silicone-based release agent can be used that is cured by an addition reaction of a silicone composition consisting of a polyorganosiloxane having two or more alkenyl groups in one molecule and an organohydrogenpolysiloxane as a crosslinking agent. In addition, a release control agent such as MQ resin may be appropriately added to the thermosetting addition-type silicone-based release agent as needed.

[0067] Thermosetting silicone-based release agents typically use platinum-based catalysts as curing catalysts. Examples of platinum catalysts include chloroplatinic acid, platinum olefin complexes, and chloroplatinic acid olefin complexes.

[0068] The thickness of the release layer of the temporary support film is preferably 0.01 to 10 μm, more preferably 0.03 to 5 μm, and even more preferably 0.1 to 1 μm, from the viewpoint of release properties and thickness stability.

[0069] (Separator film) The adhesive tape of the present invention has a structure in which a separator film with a release treatment layer on one side is laminated on an adhesive layer. The separator film is to be peeled off when using the adhesive tape.

[0070] The separator film can be made of synthetic resins similar to those used for the temporary support film, such as polyethylene, polypropylene, polyethylene terephthalate, polyamide, and polyurethane. Among these, polyethylene terephthalate film is preferred from the viewpoint of heat resistance and strength. The thickness of the separator film is usually around 6 to 200 μm, and more preferably around 12 to 100 μm from the standpoint of handling and cost.

[0071] The release agent used in the release treatment layer of the separator film can be any conventionally known agent, such as a silicone-based release agent, a long-chain alkyl-based release agent, or a fluorine-based release agent. Among these, a silicone-based release agent is preferred, and can be appropriately selected depending on the release characteristics with respect to the adhesive layer.

[0072] The thickness of the release layer is preferably 0.01 to 10 μm, more preferably 0.03 to 5 μm, and even more preferably 0.1 to 1 μm, from the viewpoint of release properties and thickness stability.

[0073] As shown in Figure 2, the manufacturing process for the adhesive tape of this embodiment is as follows: First, in the lamination process of the ionizing radiation-curable resin layer (a), an ionizing radiation-curable resin composition is applied to the release layer of the temporary support film 50 to form a laminate A70 with an ionizing radiation-curable resin layer 60. Next, in the lamination process of the adhesive layer (b), an adhesive layer composition is applied to the release layer of the separator film 40 to form an adhesive layer 30, thereby forming a laminate B80. Then, in the lamination process of the laminate (c), the surface of the ionizing radiation-curable resin layer 60 of laminate A70 and the surface of the adhesive layer 30 of laminate B80 are bonded together, and the temporary support film 50 is peeled off to form a laminate C90 in which the separator film 40 / adhesive layer 30 / ionizing radiation-curable resin layer 60 are sequentially laminated. Next, in the mold penetration step (d), a mold 100 having regularly spaced protrusions 101 on its surface that are thicker than the thickness of the ionizing radiation-curable resin layer 60 is pressed against the surface of the ionizing radiation-curable resin layer 60 of the laminate C90 that is not in contact with the adhesive layer 30, causing the protrusions 101 to penetrate the ionizing radiation-curable resin layer 60 in the thickness direction and further pushing the protrusions 101 into the adhesive layer 30. Then, in the curing step (e), with the protrusions 101 having penetrated the ionizing radiation-curable resin layer 60 and pushed into the adhesive layer 30, ionizing radiation is irradiated to cure the ionizing radiation-curable resin layer 60. Finally, in the mold removal step (f), the mold 100 is peeled off to obtain an adhesive tape 10 with a cured resin film 20 having through holes 21 as the base material and recesses 31 in the portion of the adhesive layer 30 that is in contact with the through holes 21 of the cured resin film 20. [Examples]

[0074] The adhesive tape for laser dicing of the present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0075] <Preparation of temporary support film> A release agent coating solution, prepared by mixing 95 parts by mass of silicone release agent (KS-776A, manufactured by Shin-Etsu Chemical Co., Ltd.), 5 parts by mass of curing catalyst (CAT.PL-50T, manufactured by Shin-Etsu Chemical Co., Ltd.), and 500 parts by mass of toluene, was applied to one side of a 38 μm thick polyethylene terephthalate film at a dry weight of 0.3 g / m². 2 The film was coated in this manner, then dried and cured in a gear oven at 140°C for 1 minute to form a silicone release layer, which was then used to create a separator film. <Preparing the separator film> A release agent coating solution, prepared by mixing 98 parts by mass of silicone release agent (KS-3601, manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by mass of curing catalyst (CAT.PL-50T, manufactured by Shin-Etsu Chemical Co., Ltd.), and 500 parts by mass of toluene, was applied to one side of a 38 μm thick polyethylene terephthalate film at a dry weight of 0.3 g / m². 2 The film was coated in this manner, then dried and cured in a gear oven at 140°C for 1 minute to form a silicone release layer, which was then used to create a separator film.

[0076] <Preparation of mold (mold components)> [Mold 1]; Material: Quartz glass; Protrusion shape: Cylindrical (circular with a diameter of 50 μm, height of 90 μm); Protrusion arrangement: Square lattice arrangement with 100 μm spacing in the vertical and horizontal directions; Surface treatment: Fluorine-based silane coupling agent [Mold 2]; Material: Quartz glass; Protrusion shape: Cylindrical (circular with a diameter of 40 μm, height of 90 μm); Protrusion arrangement: Square lattice arrangement with 100 μm spacing vertically and horizontally; Surface treatment: Fluorine-based silane coupling agent [Mold 3]; Material: Quartz glass; Protrusion shape: Cylindrical (circular with a diameter of 40 μm, height of 90 μm); Protrusion arrangement: Square lattice arrangement with 100 μm spacing in the vertical and horizontal directions; Surface treatment: Fluorine-based silane coupling agent

[0077] <Preparation of ionizing radiation-curable resin coating solution> 36 parts by mass of triallyl isocyanurate (molecular weight 249, carbon-carbon double bond group: trifunctional) as a polyfunctional polymerizable compound, 64 parts by mass of 1,4-bis(3-mercaptobutyryloxy)butane (molecular weight 294.4, mercapto group: bifunctional) as a polyfunctional thiol compound, 20 parts by mass of methyl ethyl ketone, and 2 parts by mass of cellulose acetate butyrate resin (Eastman Chemicals CAB381-2) were mixed and the resin was dissolved to prepare a coating solution for an ionizing radiation-curable resin layer.

[0078] <Preparation of adhesive layer coating solution> The following materials were used and mixed according to the following coating liquid formulation to create the adhesive layer coating liquid. [(meth)acrylic copolymer]; Ethyl acetate solution (non-volatile content 50%) of a copolymer of n-butyl acrylate and 2-hydroxyethyl acrylate (weight-average molecular weight 600,000, hydroxyl value 20 mg KOH / g) [Isocyanate-based curing agent]; Ethyl acetate solution of tolylene diisocyanate-trimethylolpropane (TMP) adduct (75% non-volatile content) (Coating liquid for the adhesive layer) (meth)acrylic copolymer 75 parts by mass Isocyanate-based curing agent: 5 parts by mass 20 parts by mass of ethyl acetate

[0079] (Example 1) <Fabrication of Laminate A> A coating solution for an ionizing radiation-curable resin layer was applied to the release layer surface of a temporary support film so that the film thickness after drying would be 80 μm. The solvent was then dried to create a laminate A consisting of a temporary support film and an ionizing radiation-curable resin layer. <Fabrication of Laminate B> The coating amount after drying is 15 g / m² on the release treatment layer surface of the separator film. 2 A lamination solution was applied to create the adhesive layer, and the solvent was dried to produce laminate B consisting of a separator film and an adhesive layer. <Fabrication of Laminate C> The ionizing radiation-curable resin layer surface of laminate A was bonded to the adhesive layer surface of laminate B, and the temporary support film was peeled off to produce laminate C consisting of a separator film, an adhesive layer, and an ionizing radiation-curable resin layer. <Making adhesive tape> The side of the mold 1 with the protrusions is pressed against the side of the ionizing radiation-curable resin layer of the laminate C that is not in contact with the adhesive layer, causing the protrusions of the mold 1 to penetrate the ionizing radiation-curable resin layer and further pressing in to indent the adhesive layer, and ultraviolet irradiation (high-pressure mercury lamp, output 120 W / cm, integrated light amount 1000 mJ / cm) is applied from the separator film side. 2 After curing the ionizing radiation-curable resin layer, the mold 1 was peeled off, and the adhesive layer was cured and matured at 45°C for 48 hours to produce an adhesive tape. (Pore size of cured resin film: 0.0020 mm) 2 , open area ratio: 20%)

[0080] (Example 2) In Example 1, an adhesive tape was prepared in the same manner as in Example 1, except that mold 1 was changed to mold 2. (Hole size of cured resin film: 0.0013 mm) 2 , open area ratio: 13%)

[0081] (Example 3) In Example 1, an adhesive tape was prepared in the same manner as in Example 1, except that mold 1 was changed to mold 3. (Hole size of cured resin film: 0.0028 mm) 2 , open area ratio: 28%)

[0082] (Comparative Example 1) In Example 1, the adhesive tape was prepared without using mold 1, and ultraviolet irradiation (high-pressure mercury lamp, output 120 W / cm, integrated light intensity 1000 mJ / cm) was applied from the separator film side of the laminate C. 2 After curing the ionizing radiation-curable resin layer, the adhesive layer was cured and matured at 45°C for 48 hours to produce an adhesive tape using a cured resin film without through-holes as the base material. (Base material porosity: 0%)

[0083] (Comparative Example 2) On the adhesive layer surface of laminate B in Example 1, a polypropylene film with a thickness of 80 μm (pore size of the base film: 0.50 mm) was perforated by laser processing. 2 The adhesive tape was fabricated by bonding two layers with an open area ratio of 20%, and then curing and aging the adhesive layer at 45°C for 48 hours.

[0084] <Evaluation of chip scattering during dicing> SiC (silicon carbide) wafers were diced using the adhesive tapes of Examples 1-3 and Comparative Examples 1 and 2 under the following processing conditions, and chip breakage during processing was evaluated according to the following evaluation criteria. The evaluation results for each are shown in Table 1. (Processing conditions) Processing machine: Laser microjet dicing device Dicing speed: 50 mm / s Water jet diameter: 50 μm Water jet pressure: 40 MPa Laser wavelength: 532nm Wafer size: 8 inches Wafer thickness: 100 μm Tip size: 0.6mm x 0.6mm (Evaluation Criteria) ◎: Tip drop rate is less than 0% to 0.1% ○: Tip drop rate is 0.1% to less than 3% ×: Tip drop rate is 3% or higher

[0085] <Checking for damage or cuts to the substrate> After dicing the SiC wafer under the above conditions, the cut portion of the wafer was magnified with a microscope (50x) to check for damage to the substrate film and whether it was cut, and evaluated according to the following criteria. The evaluation results are shown in Table 1. (Evaluation Criteria) ○: No damage or / or cuts were observed in the base film. ×: Damage and / or cuts are visible in the base film.

[0086] <Evaluation of adhesive residue on chips> After dicing the SiC wafer under the above conditions, 100 individual chips were peeled off the adhesive tape, and the adhesive residue (transfer of the adhesive layer) on the back of the chips was visually inspected and evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 and 3, respectively. (Evaluation Criteria) ◎: No adhesive residue left on any of the tips. ○: 1-2 chips with adhesive residue ×: Three or more chips with adhesive residue.

[0087] [Table 1] [Explanation of symbols]

[0088] 10: Adhesive tape for laser dicing 20: Cured resin film 21: Through hole 30: Adhesive layer 31: Dent 40: Separator film 50: Temporary support film 60: Ionizing radiation curable resin layer 70: Laminate A 80: Laminate B 90: Laminate C 100: Mold 101: Protrusion

Claims

[Claim 1] A method for manufacturing an adhesive tape used in laser dicing, in which a laser is guided by a water jet, wherein the adhesive tape comprises a base material and a layer of adhesive and a separator film sequentially laminated on one surface of the base material, the base material is a cured resin film obtained by curing an ionizing radiation-curable resin composition and having through holes in the thickness direction, the cured resin film is a cured product obtained by addition curing an ionizing radiation-curable resin composition by an en-thiol reaction, the polyfunctional polymerizable compound having two or more carbon-carbon double bonds in its molecule and a polyfunctional thiol compound, the polyfunctional polymerizable compound is a polyfunctional allyl compound, the polyfunctional thiol compound is a polyfunctional secondary thiol compound, and the adhesive layer has recesses in the portion of the adhesive layer that are in contact with the through holes of the cured resin film, A method for manufacturing adhesive tape for laser dicing, comprising at least the following steps (a) to (f). (a) A step of forming a laminate A on a temporary support film, in which an ionizing radiation-curable resin layer is laminated, (b) A step of forming a laminate B on a separator film by laminating an adhesive layer, (c) A step of bonding the ionizing radiation-curable resin layer surface of laminate A and the adhesive layer surface of laminate B, and then peeling off the temporary support film to form a laminate C in which the separator film / adhesive layer / ionizing radiation-curable resin layer are sequentially laminated. (d) A step of pressing a mold (mold member) having regularly spaced protrusions on its surface that are 5 to 40 μm higher than the thickness of the ionizing radiation-curable resin layer against the surface of the laminate C that is not in contact with the adhesive layer, thereby penetrating the protrusions in the thickness direction of the ionizing radiation-curable resin layer and pushing them into the adhesive layer. (e) A step of curing the ionizing radiation-curable resin layer by irradiating it with ionizing radiation while the projection has penetrated the ionizing radiation-curable resin layer and been pushed into the adhesive layer, (f) Step of peeling off the mold to obtain an adhesive tape.

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