Method for manufacturing workpiece processing sheets and semiconductor devices

Abstract

The present invention provides a workpiece processing sheet having excellent antistatic properties, and a method for manufacturing a semiconductor device using the workpiece processing sheet. [Solution] A workpiece processing sheet comprising a release sheet having a release agent layer on one side of a release substrate, and a workpiece attachment layer laminated on the side of the release agent layer opposite to the release substrate, wherein the surface resistivity of the side of the release agent layer opposite to the release substrate is 1.5 × 10 12 A workpiece machining sheet with a density of less than Ω / sq.

Description

[Technical Field]

[0001] The present invention relates to a workpiece processing sheet equipped with a release sheet and a method for manufacturing a semiconductor device using the workpiece processing sheet. [Background technology]

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

[0003] The workpiece processing sheet described above generally comprises a base material and a workpiece attachment layer laminated on one side of the base material. Depending on the application of the workpiece processing sheet, the workpiece attachment layer may include an adhesive layer, a bonding layer, or a protective film-forming layer.

[0004] For workpiece processing sheets, a release sheet is usually laminated on the side facing the workpiece attachment layer to protect that side until it is attached to the workpiece. Generally, the release sheet has a release agent layer formed on one side of a release substrate.

[0005] When using a workpiece processing sheet, the release sheet is peeled away from the adhesive surface, and at this time, static electricity called peeling charge may be generated. Furthermore, peeling charge may also occur when separating the processed workpiece from the workpiece processing sheet after processing the workpiece on the sheet. Such peeling charge can cause problems, such as the destruction of circuits formed on a semiconductor chip if the processed workpiece is one such chip.

[0006] From the viewpoint of suppressing the above-mentioned electrostatic charge from peeling, Patent Document 1 discloses an adhesive sheet having an antistatic layer on two or more sides of the adhesive layer, substrate, and release sheet, either on one side or the other side. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2010-168541 [Overview of the project] [Problems that the invention aims to solve]

[0008] Conventionally, the problem of electrostatic charge due to delamination has been discussed and examined in relation to its adverse effects on workpieces such as semiconductor chips. However, the inventors of this invention also focused on the effects of electrostatic charge on the delamination sheet itself. For example, they confirmed that the electrostatic charge on the delamination sheet itself can have adverse effects on the equipment. Furthermore, the delamination sheet is wound onto a roll by itself, and electrostatic charge is also generated due to this winding process, so antistatic properties of the delamination sheet itself are necessary in this respect as well.

[0009] This invention has been made in view of the above circumstances, and aims to provide a workpiece processing sheet having excellent antistatic properties, and a method for manufacturing a semiconductor device using the workpiece processing sheet. [Means for solving the problem]

[0010] To achieve the above objective, firstly, the present invention provides a workpiece processing sheet comprising a release sheet having a release agent layer on one side of a release substrate, and a workpiece attachment layer laminated on the side of the release agent layer opposite to the release substrate, wherein the surface resistivity of the side of the release agent layer opposite to the release substrate is 1.5 × 10 12 The invention provides a workpiece processing sheet characterized by having a density of less than Ω / sq (Invention 1).

[0011] In the sheet for workpiece processing according to the above invention (Invention 1), when the surface resistivity of the surface of the release agent layer on the opposite side from the release substrate (hereinafter sometimes referred to as the "release surface") falls within the above range, it is possible to satisfactorily suppress peeling electrification that occurs when the release sheet is peeled from the workpiece adhesive layer, and furthermore, it is also possible to satisfactorily suppress electrification that occurs when the peeled release sheet is wound up. As a result, adverse effects on workpieces such as semiconductor chips caused by electrification can be suppressed, and adverse effects on devices handling the release sheet caused by electrification can also be suppressed.

[0012] In the above invention (Invention 1), it is preferable that the release sheet contains an antistatic agent (Invention 2).

[0013] In the above invention (Invention 2), it is preferable that the antistatic agent is a conductive polymer (Invention 3).

[0014] In the above invention (Invention 2), it is preferable that the release sheet comprises an antistatic layer containing the antistatic agent (Invention 4).

[0015] In the above invention (Invention 4), it is preferable that the antistatic layer is laminated on the surface of the release substrate on the opposite side from the release agent layer (Invention 5).

[0016] In the above inventions (Inventions 1 to 5), it is preferable that the release substrate is glassine paper (Invention 6).

[0017] In the above invention (Invention 6), it is preferable that the release sheet comprises a polyethylene laminate layer laminated between the glassine paper and the release agent layer (Invention 7).

[0018] In the above inventions (Inventions 1 to 7), it is preferable that the workpiece adhesive layer is at least one selected from the group consisting of a pressure-sensitive adhesive layer, an adhesive layer and a protective film forming layer (Invention 8).

[0019] In the above inventions (Inventions 1 to 8), the workpiece processing sheet is preferably at least one selected from a dicing sheet, a back grind sheet, and an expanding sheet (Invention 9).

[0020] In the above inventions (Inventions 1 to 8), the workpiece processing sheet is preferably at least one selected from a die bond sheet, a back surface protection sheet, and a bump surface protection sheet (Invention 10).

[0021] Secondly, the present invention provides a method for manufacturing a semiconductor device, comprising: a step of attaching one or more workpieces to an exposed surface of the workpiece attachment layer exposed by peeling the release sheet from the workpiece processing sheet (Inventions 1 to 10); and a step of separating at least one of the workpieces from the workpiece attachment layer and placing the separated workpiece on a predetermined target (Invention 11). [Advantageous Effects of Invention]

[0022] The workpiece processing sheet according to the present invention has excellent antistatic properties. [Mode for Carrying Out the Invention]

[0023] Hereinafter, embodiments of the present invention will be described. The workpiece processing sheet according to the present embodiment includes: a release sheet including a release agent layer on one side of a release substrate; and a workpiece attachment layer laminated on a surface of the release agent layer opposite to the release substrate. A surface resistivity of the surface of the release agent layer opposite to the release substrate (that is, the release surface) is 1.5×10 12 less than Ω / sq.

[0024] In the workpiece processing sheet according to this embodiment, the peeling surface of the release sheet exhibits the above-mentioned surface resistivity, thereby providing excellent antistatic properties. For example, when the release sheet is peeled off from the workpiece processing sheet according to this embodiment, peeling charge can be effectively suppressed. Furthermore, because the release sheet exhibits the above-mentioned surface resistivity, the release sheet alone, separated from the workpiece adhesion layer, also possesses excellent antistatic properties. For example, even when winding up the release sheet separated from the workpiece processing sheet according to this embodiment, the generation of charge due to winding is suppressed. As a result, the workpiece processing sheet according to this embodiment can suppress adverse effects on workpieces, etc., due to peeling charge, and can also suppress adverse effects on equipment, etc., due to charge caused by winding up the release sheet.

[0025] 1. Release sheet The release sheet in this embodiment is not particularly limited as long as it can exhibit a predetermined release property and has the surface resistivity described above.

[0026] From the viewpoint of making the release sheet more likely to exhibit the aforementioned surface resistivity, it is preferable that the release sheet contains an antistatic agent. In this case, the antistatic agent may be present in any part of the release sheet. For example, the antistatic agent may be contained in the release substrate. Furthermore, as will be described later, the release sheet may have an antistatic layer containing the antistatic agent. In addition, depending on the antistatic agent, the antistatic agent can be applied to the release sheet by applying a solution containing the antistatic agent to one side of the release substrate. In this case, the antistatic agent partially penetrates the release substrate and an antistatic layer containing the antistatic agent is formed.

[0027] The antistatic agent in this embodiment is not limited as long as it can exhibit the desired antistatic properties. For example, conductive polymers, conductive fillers, anionic or cationic compounds, compounds having a quaternary ammonium base in the main chain or side chains of the molecule can be used.

[0028] While conventionally known conductive polymers can be used as the above-mentioned conductive polymer, it is preferable to use at least one of a conductive polymer having a sulfonate salt and a polythiophene-based conductive polymer. The conductive polymer may be used alone or in combination of two or more types.

[0029] Examples of conductive polymers having sulfonates include polystyrene sulfonic acid, sodium polystyrene sulfonate, lithium polystyrene sulfonate, ammonium polystyrene sulfonate, polyvinyl sulfonic acid, sodium polyvinyl sulfonate, lithium polyvinyl sulfonate, ammonium polyvinyl sulfonate, polyacrylamide sulfonic acid, sodium polyacrylamide sulfonate, lithium polyacrylamide sulfonate, ammonium polyacrylamide sulfonate, sodium naphthalene sulfonate formalin condensate, and the like.

[0030] Examples of polythiophene-based conductive polymers include polythiophene, poly(3-alkylthiophene), poly(3-thiophene-β-ethanesulfonic acid), and mixtures of polyalkylenedioxythiophene and polystyrene sulfonic acid (PSS) (including doped mixtures). Among these, a mixture of polyalkylenedioxythiophene and polystyrene sulfonic acid is preferred. Examples of the above polyalkylenedioxythiophene include poly(3,4-ethylenedioxythiophene) (PEDOT), polypropylenedioxythiophene, and poly(ethylene / propylene)dioxythiophene, with poly(3,4-ethylenedioxythiophene) being preferred. In other words, among the above, a mixture of poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) (PSS-doped PEDOT, PEDOT-PSS) is particularly preferred.

[0031] (1) Release substrate The release substrate in this embodiment is not limited as long as it can achieve the surface resistivity and function as a release sheet as described above. For example, paper or resin film can be used as the release substrate.

[0032] When using paper as the release substrate, for example, glassine paper, plain paper, or dust-free paper can be used, but glassine paper is particularly preferred. By using glassine paper, the amount of carbon dioxide emitted when the release sheet is discarded can be significantly reduced, and the amount of plastic material used can also be reduced. In particular, glassine paper emits less carbon dioxide when burned compared to general resin films. Furthermore, glassine paper is basically made from biomass, and the amount of carbon dioxide absorbed by the raw material plants can be offset from the amount of carbon dioxide emitted when burned. As a result, the actual carbon dioxide emissions from glassine paper are much lower than those from general resin films. In addition, glassine paper has the advantage of being less prone to generating dust and dirt compared to plain paper, as well as having high smoothness. This makes it easy to improve the smoothness of the release sheet itself, and consequently, the smoothness of the surface of the workpiece attachment layer attached to the release sheet is also improved. As a result, by using the workpiece processing sheet according to this embodiment, high-precision workpiece processing becomes possible.

[0033] The glassine paper in this embodiment is not particularly limited, and known types can be used. The pulp constituting the glassine paper can be known, and for example, wood pulps such as softwood kraft pulp (N material), hardwood kraft pulp (L material), softwood sulfite pulp, hardwood sulfite pulp, dissolved pulp, and mercerized pulp, as well as non-wood pulps such as flax pulp, Manila hemp pulp, and kenaf pulp can be used. Among these, it is preferable to use at least one of softwood kraft pulp and hardwood kraft pulp, and it is particularly preferable to use a combination of softwood kraft pulp and hardwood kraft pulp.

[0034] When using a combination of softwood kraft pulp and hardwood kraft pulp, it is preferable to use them in a ratio of softwood kraft pulp to hardwood kraft pulp of 5:95 to 50:50, and particularly preferable to use them in a ratio of 15:85 to 40:60.

[0035] Furthermore, the glassine paper in this embodiment may have various additives added to the pulp, examples of which include fillers, wet strength enhancers, dry strength enhancers, sizing agents, aluminum sulfate, various yield enhancers of anionic, cationic, nonionic, and amphoteric types, water drainage enhancers, color dyes, color pigments, fluorescent whitening agents, pH adjusters, defoamers, pitch control agents, slime control agents, and the like. The glassine paper in this embodiment may also contain the antistatic agent mentioned above.

[0036] The method for beating the pulp as described above is not particularly limited, and it can be beating using a known refiner or the like. Then, by processing the beating pulp under high pressure using a smooth roller such as a supercalender, the glassine paper of this embodiment can be obtained.

[0037] The basis weight of the glassine paper in this embodiment is 30 g / m². 2 It is preferable that the amount be greater than or equal to 40 g / m², and particularly 40 g / m². 2 Preferably, it is 45 g / m² or more, and more preferably 45 g / m² 2 It is preferable that the basis weight is 150 g / m². 2 Preferably, it is 120 g / m² or less, and especially 120 g / m². 2 Preferably the following, and moreover 100g / m 2 The following is preferable: When the basis weight of the glassine paper is within the above range, the release sheet will have sufficient strength while also being easy to handle.

[0038] In this embodiment, the thickness of the glassine paper is preferably 20 μm or more, particularly preferably 25 μm or more, and even more preferably 30 μm or more. Furthermore, the thickness is preferably 200 μm or less, particularly preferably 180 μm or less, and even more preferably 160 μm or less. When the thickness of the glassine paper is within the above range, the release sheet has sufficient strength while also being easy to handle.

[0039] Furthermore, when glassine paper is used as the release substrate, it is preferable that the release sheet in this embodiment further comprises a polyethylene laminate layer laminated between the glassine paper and the release agent layer. By including the polyethylene laminate layer, the smoothness of the release agent layer side (release surface) of the release sheet can be further improved. Details of the polyethylene laminate layer will be described later.

[0040] In this embodiment, it is also preferable to use a resin film as the release substrate. Specific examples of resin films 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 copolymer films such as ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylate methyl copolymer film, and other ethylene-(meth)acrylic acid ester copolymer films; polyvinyl chloride films such as polyvinyl chloride film and vinyl chloride copolymer film; (meth)acrylic acid ester copolymer film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; and fluororesin film. Modified films such as crosslinked films and ionomer films can also be used. The substrate may also be a laminated film formed by laminating multiple of the above-mentioned films. In this laminated film, the materials constituting each layer may be the same or different. In this specification, "(meth)acrylic acid" refers to both acrylic acid and methacrylic acid. The same applies to other similar terms. Furthermore, in this specification, "polymer" includes the concept of "polymer."

[0041] The resin film may contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers. Furthermore, the resin film may contain the aforementioned antistatic agents.

[0042] The surface on which the adhesive layer of the resin film is laminated may be subjected to surface treatments such as primer treatment, corona treatment, or plasma treatment in order to improve adhesion with the adhesive layer.

[0043] Although the thickness of the resin film can be appropriately set depending on the method by which the workpiece processing sheet is used, for example, it is preferably 200 μm or less, and particularly preferably 150 μm or less. Further, the thickness of the resin film is preferably 10 μm or more, and particularly preferably 25 μm or more.

[0044] (2) Release agent layer The release agent constituting the release agent layer in the present embodiment is not particularly limited, and general release agents used for release sheets can be used. As the release agent, silicone-based release agents, fluorine-based release agents, long-chain alkyl release agents, rubber-based release agents and the like can be appropriately used. Among these, silicone-based release agents are preferred because they provide inexpensive and stable performance.

[0045] The release agent layer in the present embodiment can be formed by a general method. For example, when forming a release agent layer using a silicone-based release agent, a release agent composition that serves as a material for the silicone-based release agent is applied to one side of the release base material (when a polyethylene laminate layer is provided, the surface on the polyethylene laminate layer side), and the obtained coating film is subjected to treatment such as heating and cured to obtain the release agent layer.

[0046] The basis weight of the release agent layer in the present embodiment is 0.1 g / m 2 or more, particularly 0.3 g / m 2 or more is preferred. Further, the basis weight is 1.5 g / m 2 or less, particularly 1.0 g / m 2 or less is preferred. When the basis weight of the release agent layer falls within the above range, it becomes easy to form a release agent layer that exhibits good releasability.

[0047] In this embodiment, the thickness of the release agent layer is preferably 50 nm or more, particularly preferably 100 nm or more, and even more preferably 200 nm or more. Furthermore, the thickness is preferably 1000 nm or less, particularly preferably 800 nm or less, and even more preferably 700 nm or less. Having the thickness of the release agent layer within the above range makes it easier to form a release agent layer that exhibits good release properties.

[0048] (3) Antistatic layer As described above, the release sheet in this embodiment may include an antistatic layer containing an antistatic agent. The position of the antistatic layer in the release sheet is not particularly limited; for example, it may be laminated between the release substrate and the release agent layer, but it is preferable that it be laminated on the side of the release substrate opposite to the release agent layer.

[0049] Furthermore, if the release sheet in this embodiment includes a polyethylene laminate layer, the other layer configurations are not limited as long as the release agent layer is located on the release surface side (one of the outermost surfaces). For example, it is preferable that the antistatic layer, the release substrate, the polyethylene laminate layer, and the release agent layer are laminated in this order.

[0050] The composition of the antistatic layer in this embodiment is not particularly limited, as long as it contains the antistatic agent described above. The antistatic layer may optionally contain at least one of the following additives: a binder resin, a crosslinking agent, an antifoaming agent, a coating property improver, a thickener, an organic lubricant, organic particles, or inorganic particles.

[0051] One method for forming the antistatic layer is to immerse the release substrate in a coating solution containing the antistatic agent described above, and then dry the resulting coating film. Alternatively, the antistatic layer can also be formed by applying the coating solution to one or both sides of the substrate and then drying the resulting coating film.

[0052] The thickness of the antistatic layer can be set as appropriate, and is preferably 0.003 μm or more, and particularly preferably 0.005 μm or more. Furthermore, the thickness is preferably 1.5 μm or less, and particularly preferably 0.5 μm or less.

[0053] (4) Polyethylene laminate layer As mentioned above, when glassine paper is used as the release substrate, the release sheet in this embodiment preferably comprises a polyethylene laminate layer laminated between the glassine paper and the release agent layer.

[0054] In this embodiment, a polyethylene laminate layer that is commonly used for laminating onto glassine paper can be used as the polyethylene laminate layer. That is, it is preferable that the polyethylene laminate layer in this embodiment is formed by laminating polyethylene, which has been melted by heating, onto one side of the glassine paper under pressure using a smooth roll.

[0055] As the polyethylene mentioned above, low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), etc., can be used as appropriate depending on the purpose.

[0056] When melting polyethylene, it is preferable to heat it to 95-160°C, particularly 100-140°C. Furthermore, it is preferable to use an ultra-high smooth roll as the smooth roll.

[0057] In this embodiment, the thickness of the polyethylene laminate layer is preferably 5 μm or more, particularly preferably 8 μm or more, and even more preferably 10 μm or more. Furthermore, the thickness is preferably 40 μm or less, and particularly preferably 30 μm or less. When the thickness of the polyethylene laminate layer is above the lower limit, the smoothness of the release surface of the release sheet is improved. Furthermore, when the thickness of the polyethylene laminate layer is below the upper limit, the amount of carbon dioxide emitted can be further reduced.

[0058] (5) Surface roughness In this embodiment, the release sheet preferably exhibits the following surface roughness on its release surface. Specifically, the arithmetic mean roughness Ra of the release surface is preferably 2.0 μm or less, particularly preferably 1.5 μm or less, and even more preferably 1.4 μm or less. When the arithmetic mean roughness Ra of the release surface is within the above range, the release surface becomes smoother, and the smoothness of the workpiece adhesive layer laminated on the release surface becomes even better. As a result, it becomes easier to perform high-precision workpiece processing using the workpiece processing sheet according to this embodiment. The lower limit of the arithmetic mean roughness Ra is not particularly limited, and may be, for example, 0.01 μm or more, particularly 0.05 μm or more, and even more preferably 0.1 μm or more.

[0059] The details of the measurement method for the arithmetic mean roughness Ra described above were obtained using a non-contact surface measurement system in accordance with ISO 25178. As the non-contact surface measurement system, a system using direct phase detection interferometry, also known as Michelson interference, specifically a two-beam interferometry system (manufactured by Hitachi High-Tech Science Corporation, product name "Vertscan"), can be used.

[0060] 2. Workpiece bonding layer The workpiece attachment layer in this embodiment is not particularly limited as long as it is a layer to which a workpiece can be attached. Specifically, the workpiece attachment layer is preferably at least one of an adhesive layer, a bonding layer, and a protective film forming layer. These layers can be appropriately selected depending on the application of the workpiece processing sheet.

[0061] In this embodiment, the workpiece processing sheet is preferably used as at least one of the following: a dicing sheet, a back grind sheet, an expanded sheet, a die bond sheet, a back surface protection sheet, and a bump surface protection sheet. Of these, if the workpiece processing sheet is a dicing sheet, a back grind sheet, or an expanded sheet, the workpiece attachment layer is preferably an adhesive layer. If the workpiece processing sheet is a die bond sheet, the workpiece attachment layer is preferably an adhesive layer. Furthermore, if the workpiece processing sheet is a back surface protection sheet or a bump surface protection sheet, the workpiece attachment layer is preferably a protective film forming layer.

[0062] (1) Adhesive layer As the adhesive layer mentioned above, a common adhesive layer used for dicing sheets, backgrind sheets, expanded sheets, etc., can be used. As the adhesive constituting the adhesive layer, for example, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, etc., can be used. Among these, acrylic adhesives are preferred from the viewpoint of easily exhibiting the desired adhesive strength.

[0063] Furthermore, the adhesive constituting the adhesive layer may be one that does not have active energy ray curability, one that has active energy ray curability, one that is heat-foaming, or one that has the property of foaming when exposed to active energy rays. Among these, one that has active energy ray curability is preferred. By using an active energy ray curable adhesive, the adhesive layer can be cured by irradiation with active energy rays, making it possible to easily separate the workpiece from the adhesive layer.

[0064] The above-mentioned active energy ray curable adhesive may be mainly composed of a polymer having active energy ray curability, or it may be mainly composed of a mixture of an active energy ray non-curable polymer (a polymer that does not have active energy ray curability) and a monomer and / or oligomer having at least one active energy ray curable group. Alternatively, the active energy ray curable adhesive may be a mixture of an active energy ray curable polymer and a monomer and / or oligomer having at least one active energy ray curable group.

[0065] The polymer having active energy ray curability described above is preferably a (meth)acrylic acid ester polymer (hereinafter sometimes referred to as "active energy ray curable polymer") in which a functional group having active energy ray curability (active energy ray curable group) is introduced into the side chain. This active energy ray curable polymer is preferably obtained by reacting an acrylic polymer having a functional group-containing monomer unit with an unsaturated group-containing compound having a functional group that is bonded to the functional group.

[0066] The acrylic polymer having the functional group-containing monomer units described above may be obtained by polymerizing the functional group-containing monomer together with other monomers. Known functional group-containing monomers and other monomers, as well as the unsaturated group-containing compounds described above, can be used, for example, those disclosed in International Publication No. 2018 / 084021.

[0067] The weight-average molecular weight of the above-mentioned active energy ray-curable polymer is preferably 10,000 or more, particularly preferably 150,000 or more, and even more preferably 200,000 or more. Furthermore, the weight-average molecular weight is preferably 1,500,000 or less, and particularly preferably 1,000,000 or less. In this specification, the weight-average molecular weight (Mw) is a value on a standard polystyrene basis measured by gel permeation chromatography (GPC).

[0068] As the above-mentioned active energy ray non-curable polymer, for example, the (meth)acrylic acid ester polymer before reacting with the unsaturated group-containing compound can be used.

[0069] The weight-average molecular weight of the (meth)acrylic acid ester polymer, which is the above-mentioned active energy ray noncurable polymer, is preferably 10,000 or more, particularly preferably 150,000 or more, and even more preferably 200,000 or more. Furthermore, the weight-average molecular weight is preferably 1,500,000 or less, and particularly preferably 1,000,000 or less.

[0070] Furthermore, as monomers and / or oligomers having at least one active energy ray curable group as described above, for example, esters of polyhydric alcohols and (meth)acrylic acid can be used.

[0071] It is also preferable to add a crosslinking agent to the above-mentioned active energy ray-curable adhesive. By using a crosslinking agent, the active energy ray-curable adhesive is more likely to have the desired cohesive force. As the crosslinking agent, a polyfunctional compound that has reactivity with the functional groups of the active energy ray-curable adhesive can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, and reactive phenolic resins. The amount of crosslinking agent is not particularly limited and can be appropriately determined, for example, in the range of 1 to 15 parts by mass per 100 parts by mass of the active energy ray-curable adhesive.

[0072] Furthermore, when ultraviolet light is used as the active energy ray for curing an active energy ray-curable adhesive, it is preferable to add a photopolymerization initiator to the adhesive. By using a photopolymerization initiator, it is possible to effectively reduce the polymerization curing time and the amount of light irradiation required for the adhesive, especially when ultraviolet light is used as the active energy ray.

[0073] In this embodiment, when the workpiece attachment layer is an adhesive layer, the thickness of the adhesive layer is preferably 3 to 50 μm, particularly preferably 5 to 40 μm, and even more preferably 10 to 20 μm. Having the adhesive layer thickness within this range makes it easier for the workpiece attachment layer to exhibit the desired adhesive strength.

[0074] (2) Adhesive layer When the workpiece attachment layer in this embodiment is an adhesive layer, as described above, the workpiece processing sheet according to this embodiment is typically used as a die bond sheet. Therefore, there are no particular restrictions on the material that constitutes the adhesive layer, as long as it can form an adhesive layer on the workpiece.

[0075] Materials used to constitute such adhesive layers include those consisting of a thermoplastic resin and a low molecular weight thermosetting adhesive component, or those consisting of a B-stage (semi-cured) thermosetting adhesive component. Among these, it is preferable that the materials constituting the adhesive layer include a thermoplastic resin and a thermosetting adhesive component. Examples of thermoplastic resins include (meth)acrylic copolymers, polyester resins, urethane resins, phenoxy resins, polybutene, polybutadiene, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, ethylene (meth)acrylic acid copolymers, ethylene (meth)acrylic acid ester copolymers, polystyrene, polycarbonate, and polyimide. Among these, (meth)acrylic copolymers are preferred in terms of tackiness and film-forming properties (sheet processability). Examples of thermosetting adhesive components include epoxy resins, polyimide resins, phenolic resins, silicone resins, cyanate resins, bismaleimidotriazine resins, allylated polyphenylene ether resins (thermosetting PPE), formaldehyde resins, unsaturated polyesters, or copolymers thereof. Among these, epoxy resins are preferred from the viewpoint of adhesion.

[0076] In this embodiment, when the workpiece attachment layer is an adhesive layer, the thickness of the adhesive layer can be appropriately selected depending on the purpose, and for example, it is preferably 1 to 50 μm, particularly preferably 3 to 25 μm, and even more preferably 5 to 20 μm.

[0077] (3) Protective film forming layer In this embodiment, if the workpiece attachment layer is a protective film forming layer, it is preferable that the protective film forming layer is made of an uncured curable adhesive. In this case, after stacking a workpiece such as a semiconductor wafer or semiconductor chip on the protective film forming layer, the protective film can be firmly adhered to the workpiece by curing the protective film forming layer. As a result, a protective film with excellent durability can be formed on the workpiece.

[0078] The protective film-forming layer is preferably adhesive at room temperature or exhibits adhesiveness upon heating. This allows the workpiece to be bonded to the protective film-forming layer when it is placed on top of it, as described above. The curable adhesive constituting the protective film-forming layer having such properties preferably contains a curable component and a binder polymer component. As the curable component, a thermosetting component, an energy ray curable component, or a mixture thereof can be used. From the viewpoint of the curing method of the protective film-forming layer and the heat resistance after curing, the use of a thermosetting component is particularly preferred, and from the viewpoint of curing time, the use of an energy ray curable component is preferred.

[0079] In this embodiment, when the workpiece attachment layer is a protective film forming layer, the thickness of the protective film forming layer can be appropriately selected depending on the purpose. For example, it is preferably 3 to 50 μm, particularly preferably 5 to 45 μm, and even more preferably 10 to 25 μm. Furthermore, when the object to be attached is the surface of a workpiece having bumps on its surface, the thickness of the protective film forming layer is preferably 5 to 50 μm, particularly preferably 10 to 30 μm, and even more preferably 15 to 25 μm. Moreover, when used in a process to fill grooves in a workpiece having grooves on its surface with a protective film forming layer, the thickness of the protective film forming layer is preferably 20 to 75 μm, particularly preferably 30 to 60 μm, and even more preferably 40 to 55 μm.

[0080] (4) Layer composition The workpiece processing sheet according to this embodiment may include other components as appropriate, depending on the application of the workpiece processing sheet and the specific type of workpiece adhesive layer.

[0081] For example, when a workpiece processing sheet is used as a dicing sheet, backgrinding sheet, or expandable sheet, and the workpiece attachment layer is an adhesive layer, it is preferable that a base material is laminated on the side of the workpiece attachment layer (adhesive layer) opposite to the release sheet. By providing a base material, when the release sheet is peeled off from the workpiece processing sheet, the workpiece attachment layer is supported by the base material, making it easier to process the workpiece on the workpiece attachment layer.

[0082] Furthermore, even when a workpiece processing sheet is used as a die bond sheet and the workpiece attachment layer is an adhesive layer, it is preferable that the base material is laminated on the side of the workpiece attachment layer (adhesive layer) opposite to the release sheet. By providing a base material, the workpiece attachment layer is supported by the base material, making it easier to laminate the adhesive layer onto the workpiece smoothly.

[0083] Furthermore, in the case where the workpiece processing sheet is a back-side protective sheet and the workpiece attachment layer is a protective film forming layer, in the first embodiment, it is preferable that an adhesive layer is laminated on the side of the workpiece attachment layer (protective film forming layer) opposite to the release sheet, and a base material is laminated on the side of the adhesive layer opposite to the workpiece attachment layer. In this configuration, the workpiece attachment layer, adhesive layer, and base material are laminated in order to the release sheet, making it easier to transfer the workpiece attachment layer (protective film forming layer) to the target workpiece. In the second embodiment, it is also preferable that another release sheet is laminated on the side of the workpiece attachment layer (protective film forming layer) opposite to the release sheet. In such a case, the workpiece processing sheet can transfer the protective film forming layer to the workpiece without a base material.

[0084] Furthermore, when the workpiece processing sheet is a bump protection sheet and the workpiece attachment layer is a protective film forming layer, it is preferable that an intermediate release agent layer is laminated on the side of the workpiece attachment layer (protective film forming layer) opposite to the release sheet, a buffer layer is laminated on the side of the intermediate release agent layer opposite to the workpiece attachment layer, and a base material is laminated on the side of the buffer layer opposite to the intermediate release layer. With this configuration, it becomes easier to transfer the workpiece attachment layer (protective film forming layer) to the target bumped workpiece.

[0085] The aforementioned substrates may be any known materials, depending on the purpose, and for example, it is preferable to use a resin film.

[0086] 3. Method for manufacturing workpiece processing sheets The method for manufacturing the workpiece processing sheet according to this embodiment is not particularly limited. For example, a workpiece adhesive layer can be formed on the release surface of the release sheet manufactured as described above, and then, if necessary, a base material or the like can be laminated on the side of the workpiece adhesive layer opposite to the release sheet to obtain the desired workpiece processing sheet.

[0087] The workpiece adhesion layer on the release surface of the release sheet can be formed by known methods. For example, when forming an adhesive layer as the workpiece adhesion layer, a coating liquid containing an adhesive composition constituting the adhesive layer, and optionally a solvent or dispersion medium, can be prepared. This coating liquid can then be applied to the release surface of the release sheet using a die coater, curtain coater, spray coater, slit coater, knife coater, roll knife coater, applicator, etc., to form a coating film, and the coating film can be 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 dispersed phase.

[0088] If the coating liquid for forming the adhesive layer contains a crosslinking agent, the crosslinking reaction between the active energy ray-curable polymer and the crosslinking agent in the coating film can be promoted by changing the drying conditions (temperature, time, etc.) or by providing a separate heat treatment, thereby forming a crosslinked structure with a desired density in the adhesive layer. To ensure this crosslinking reaction progresses sufficiently, after laminating the adhesive layer onto the substrate by the method described above, the resulting workpiece processing sheet may be cured by, for example, leaving it undisturbed in an environment of 23°C and 50% relative humidity for several days.

[0089] 4. How to use the workpiece processing sheet The workpiece processing sheet according to this embodiment can be used for processing workpieces. That is, the release sheet can be peeled off from the workpiece processing sheet according to this embodiment, and the exposed surface of the workpiece adhesive layer that is thus exposed can be attached to one side of the workpiece, and then the workpiece can be processed on the workpiece processing sheet.

[0090] Examples of the above processing include dicing, back grinding, expanding, picking, die bonding, back surface protection, bump surface protection, etc.

[0091] The workpiece processed using the workpiece processing sheet according to this embodiment is not particularly limited and includes, for example, semiconductor wafers, semiconductor packages and other semiconductor components, and glass plates and other glass components.

[0092] When the semiconductor material described above is used as the workpiece, the workpiece processing sheet according to this embodiment is also preferably used in a method for manufacturing a semiconductor device. This manufacturing method includes, for example, the steps of peeling off the release sheet from the workpiece processing sheet according to this embodiment and attaching one or more workpieces to the exposed surface of the workpiece attachment layer, and separating at least one of the workpieces from the workpiece attachment layer and placing it on a predetermined object. The above-described attachment and separation can be carried out using known methods.

[0093] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Accordingly, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Examples]

[0094] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0095] [Example 1] (1) Preparation of release sheet By beating 30 parts by mass of softwood kraft pulp (N material) and 70 parts by mass of hardwood kraft pulp (L material), a pulp slurry is obtained, and the basis weight is 62 g / m². 2 I obtained glassine paper.

[0096] Molten polyethylene was laminated onto one side of the glassine paper using a two-roll size press coater with an ultra-high smooth (ultra-mirror) roll surface. This resulted in a laminate in which a 19 μm thick polyethylene laminate layer was formed on one side of a 58 μm thick glassine paper.

[0097] Next, anionic polystyrene sulfonate (manufactured by Fujistat, product name "YE908") as an antistatic agent was applied to the glassine paper side of the laminate at a rate of 0.13 g / m² using a bar coater. 2 The coating was applied at a certain basis weight, and the resulting coating film was dried to form an antistatic layer.

[0098] Furthermore, a silicone-based release agent (manufactured by Shin-Etsu Silicone Co., Ltd., product name "KNS-320A") is applied as a release agent composition to the polyethylene laminate layer side of the laminate using a bar coater at a rate of 0.50 g / m². 2 The coating was applied at a specific basis weight, and the resulting film was heated at 100°C for 30 seconds. This caused the film to harden and form a release agent layer.

[0099] As a result, a release sheet was obtained in which a release agent layer, a polyethylene laminate layer, glassine paper, and an antistatic layer were laminated in that order.

[0100] (2) Preparation of workpiece processing sheets 70 parts by mass of n-butyl acrylate, 15 parts by mass of methyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer. Subsequently, 2-methacryloyloxyethyl isocyanate (MOI) in an amount equivalent to 80 mol% of the 2-hydroxyethyl acrylate constituting the (meth)acrylic acid ester polymer was reacted to obtain a (meth)acrylic acid ester polymer (active energy ray curable polymer) in which active energy ray curable groups were introduced into the side chains. The weight-average molecular weight of this active energy ray curable polymer was measured by the method described later and was found to be 600,000.

[0101] The above-mentioned active energy ray-curable polymer (100 parts by mass, on a solid content basis, the same applies hereafter) was mixed with 0.6 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Toso Corporation, product name "Coronate L") as a crosslinking agent and 3 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, product name "Irgacure 184") in a solvent to obtain a coating solution of an adhesive composition with a solid content concentration of 20%.

[0102] The adhesive composition solution obtained as described above was applied to the release surface of the release sheet prepared in step (1) above, and the resulting coating film was dried by heating. This resulted in a laminate in which the 5 μm thick adhesive layer formed by the drying of the coating film and the release sheet were laminated together.

[0103] By bonding one side of an ethylene-methyl methacrylate (EMMA) sheet (thickness: 80 μm) as a base material to the adhesive layer side of the laminate, a workpiece processing sheet was obtained in which the release surface of the release sheet prepared in step (1) above was laminated onto the adhesive surface of the adhesive sheet consisting of the base material and the adhesive layer.

[0104] (3) Measurement of weight-average molecular weight The weight-average molecular weight (Mw) mentioned above is the weight-average molecular weight on a standard polystyrene basis, measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement). <Measurement conditions> • Measuring device: Tosoh Corporation, HLC-8320 • GPC column (passes through in the following order): Manufactured by Tosoh Corporation TSK Gel Super H-H TSK gel superHM-H TSK Gel Super H2000 • Measurement solvent: tetrahydrofuran ·Measurement temperature: 40℃

[0105] [Example 2] A workpiece processing sheet with a release liner was obtained in the same manner as in Example 1, except that a composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) (PEDOT-PSS) (manufactured by Chukyo Oil & Fat Co., Ltd., product name "W-787") was used as an antistatic agent.

[0106] [Example 3] A composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) (PEDOT-PSS) (manufactured by Chukyo Oil & Fat Co., Ltd., product name "W-787") was applied as an antistatic agent to one side of a polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil® T100", thickness: 38 μm) using a bar coater at a rate of 0.13 g / m². 2 The coating was applied at a certain basis weight, and the resulting coating film was dried to form an antistatic layer.

[0107] On the other hand, a mixture of a linear polyorganosiloxane with trivinyl-modified ends, a branched vinyl-modified organosiloxane oligomer, and a polymethylhydrogensiloxane (mass-average molecular weight: 287,000) was diluted with methyl ethyl ketone (MEK) to a solid content of 30% by mass. To 100 parts by mass of this diluted solution, 2 parts by mass of a platinum-based catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., product name "PL-50T") was added, and the solid content was adjusted with MEK to a solid content concentration of 0.7% by mass to obtain a coating solution for an addition-reaction type silicone resin composition.

[0108] The resulting coating solution has a film thickness of 0.04 g / m² after drying. 2 To achieve this, the above-mentioned release agent layer was formed by uniformly applying the antistatic layer to the side of the PET film opposite to the antistatic layer using the bar coating method, and then drying it at 130°C for 1 minute. This resulted in a release sheet in which the release agent layer, the PET film, and the antistatic layer were laminated in that order.

[0109] A workpiece processing sheet with a release sheet was obtained in the same manner as in Example 1, except that the release sheet was used.

[0110] [Comparative Example 1] A workpiece processing sheet with a release sheet was obtained in the same manner as in Example 3, except that an antistatic layer was not formed.

[0111] [Comparative Example 2] A release sheet was obtained in the same manner as in Example 1, except that a release agent layer and an antistatic layer were not formed, by sequentially laminating a polyethylene laminate layer and glassine paper. Furthermore, using this release sheet, a workpiece processing sheet with a release sheet was obtained in the same manner as in Example 1.

[0112] [Test Example 1] (Measurement of surface resistivity) The release sheets manufactured in the examples and comparative examples were cut into 100 mm x 100 mm pieces, and these were used as samples for surface resistivity measurement. After conditioning these samples at 23°C and 50% relative humidity for 24 hours, the surface resistivity (Ω / □) of the release surface was measured using a digital electrometer (manufactured by ADVANTEST) with an applied voltage of 100 V. The obtained values ​​(Ω / □) are shown in Table 1 as surface resistivity.

[0113] [Test Example 2] (Measurement of delamination voltage) The workpiece processing sheets with release liner obtained in the examples and comparative examples were cut to 100 mm x 300 mm, and these were used as samples for measuring the release band voltage. Then, in an environment of 23°C and 50% relative humidity, the release liner was manually peeled off from the sample at a peeling angle of 90 degrees and a peeling speed of 300 mm / min. Immediately after peeling, the electrostatic potential (release band voltage; kV) at a position 50 mm from the exposed surface of the adhesive layer was measured using an electric field meter (Prostat, product name "PFM-711A"). The results are shown in Table 1.

[0114] [Test Example 3] (Calculation of carbon dioxide emissions) For the release sheets prepared in the examples and comparative examples, the density of the glassine paper, polyethylene laminate layer, PET film, and clean paper used in each was determined from the density of these materials per 1 m 2The weight per unit was calculated. Furthermore, based on the combustion reaction equations of these components, the amount of carbon dioxide emitted when these components are burned was calculated for each component. Then, for these emissions, the coefficients listed in the list of greenhouse gas emission factors published by the Ministry of the Environment were used to calculate the amount per cubic meter. 2 The amount of carbon dioxide emissions generated when the product is discarded was identified for each component. Furthermore, by obtaining the sum of the carbon dioxide emissions of the components that make up each release sheet, the total carbon dioxide emissions of the release sheet (g-CO2) were determined. 2e / m 2 The result was obtained. The results are shown in Table 1.

[0115] Although the release sheet has a release agent layer and an antistatic layer, the mass of these layers is very small compared to other components, and the carbon dioxide emissions from these layers are very small compared to other components, so the carbon dioxide emissions from these layers were not considered.

[0116] [Table 1]

[0117] As can be seen from Table 1, the workpiece processing sheet with a release sheet obtained in the example was able to suppress the release voltage to a lower level compared to the comparative example. Therefore, it was found that the workpiece processing sheet with a release sheet according to the example has excellent antistatic properties.

[0118] Furthermore, as can be seen from Table 1, the workpiece processing sheets with release sheets obtained in Examples 1 and 2 significantly reduced the amount of carbon dioxide emitted when the release sheet was discarded compared to Examples 3 and Comparative Example 1, which used a resin-based release substrate. [Industrial applicability]

[0119] The workpiece processing sheet of the present invention can be suitably used for processing workpieces such as semiconductor wafers.

Claims

1. A release sheet comprising a release agent layer on one side of a release substrate, A workpiece adhesive layer laminated on the side of the release agent layer opposite to the release substrate, A workpiece processing sheet equipped with, The surface resistivity of the release agent layer on the side opposite to the release substrate is 1.5 × 10 １２ Less than Ω / sq A workpiece processing sheet characterized by the following features.

2. The release sheet is characterized by containing an antistatic agent, as described in claim 1.

3. The workpiece processing sheet according to claim 2, characterized in that the antistatic agent is a conductive polymer.

4. The workpiece processing sheet according to claim 2, characterized in that the release sheet comprises an antistatic layer containing the antistatic agent.

5. The workpiece processing sheet according to claim 4, characterized in that the antistatic layer is laminated on the side of the release substrate opposite to the release agent layer.

6. The workpiece processing sheet according to claim 1, characterized in that the release substrate is glassine paper.

7. The workpiece processing sheet according to claim 6, characterized in that the release sheet comprises a polyethylene laminate layer laminated between the glassine paper and the release agent layer.

8. The workpiece processing sheet according to claim 1, characterized in that the workpiece attachment layer is at least one of an adhesive layer, a bonding layer, and a protective film forming layer.

9. The workpiece processing sheet according to claim 1, characterized in that the workpiece processing sheet is at least one of a dicing sheet, a backgrinding sheet, and an expanded sheet.

10. The workpiece processing sheet according to claim 1, characterized in that the workpiece processing sheet is at least one of a die bond sheet, a back surface protection sheet, and a bump surface protection sheet.

11. A step of peeling off the release sheet from the workpiece processing sheet according to any one of claims 1 to 10 and attaching one or more workpieces to the exposed surface of the workpiece attachment layer that has been exposed, A step of separating at least one of the workpieces from the workpiece attachment layer and placing it on a predetermined object. A method for manufacturing a semiconductor device, characterized by comprising the above.

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