Semiconductor processing sheet, semiconductor device manufacturing method, and use of semiconductor processing sheet

Abstract

To provide a semiconductor processing sheet that allows sufficient separation between semiconductor chips and adequate pickup of the semiconductor chips even when not performing dicing.SOLUTION: Provided is a semiconductor processing sheet that comprises a base material and an adhesive layer laminated on one side of the base material. The adhesive layer is configured by an adhesive with active energy-ray curability. A gel fraction of the adhesive after ultraviolet irradiation is 85% to 97%. A ratio of a surface resistivity of the adhesive layer before ultraviolet irradiation to that after ultraviolet irradiation (the surface resistivity before ultraviolet irradiation / the surface resistivity after ultraviolet irradiation) is equal to or more than 0.5.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a semiconductor processing sheet that can be suitably used for processing semiconductors, a method for manufacturing a semiconductor device, and the use of the semiconductor processing sheet. [Background technology]

[0002] Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in large diameters, cut and separated (diced) into small element pieces (semiconductor chips), and then individually peeled (picked up) before being transferred to the next process, the mounting process. During this process, the semiconductor wafer or other workpiece is attached to a semiconductor processing sheet comprising a base material and an adhesive layer, and undergoes processing such as backgrinding, dicing, cleaning, drying, expanding, picking up, and mounting. Patent Documents 1 and 2 disclose examples of such semiconductor processing sheets.

[0003] In the above-mentioned pickup process, in order to prevent the semiconductor chip to be picked up from colliding with the adjacent semiconductor chip, the semiconductor processing sheet is generally stretched (expanded) to separate the semiconductor chips. If the semiconductor chips collide with each other during pickup, not only will the pickup fail, but the semiconductor chips may also be damaged, so it is necessary to sufficiently prevent the occurrence of such collisions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5027321 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-120624 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, one of the problems of the semiconductor processing sheet disclosed in the above-mentioned Patent Document 1 is to suppress chip flying during dicing. That is, the semiconductor processing sheet disclosed in Patent Document 1 is premised on being used for dicing. Meanwhile, the semiconductor processing sheet disclosed in Patent Document 2 is a dicing sheet used for dicing.

[0006] In the semiconductor processing sheets used for dicing as described above, the adhesive layer and part of the substrate are usually cut along with the semiconductor wafer during dicing. When these semiconductor processing sheets are expanded after dicing, the adhesive layer is divided and the substrate is also notched, allowing for sufficient expansion.

[0007] On the other hand, if an attempt is made to expand a semiconductor processing sheet without dicing, the adhesive layer and the base material remain integrated as they were originally, and therefore sufficient expansion cannot be achieved, and the semiconductor chips cannot be spaced apart sufficiently, resulting in poor pickup.

[0008] The present invention was made in consideration of the above-mentioned situation, and aims to provide a semiconductor processing sheet that can sufficiently space semiconductor chips from each other even when dicing is not performed, and that enables good pickup of semiconductor chips. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, first, the present invention provides a semiconductor processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the adhesive layer is composed of an adhesive having active energy ray curability, the gel fraction of the adhesive after ultraviolet irradiation is 85% or more and 97% or less, and the ratio of the surface resistivity of the adhesive layer before ultraviolet irradiation to the surface resistivity of the adhesive layer after ultraviolet irradiation (surface resistivity before ultraviolet irradiation / surface resistivity after ultraviolet irradiation) is 0.5 or more (Invention 1).

[0010] The semiconductor processing sheet according to the above invention (Invention 1) has an adhesive layer that satisfies the above-mentioned physical properties, allowing for sufficient expansion and good pick-up of semiconductor chips. In particular, since the gel fraction of the adhesive constituting the adhesive layer after UV irradiation is within the above-mentioned range, cured and uncured regions are appropriately distributed within the adhesive layer after active energy ray curing, which facilitates good expansion of the adhesive layer. Furthermore, since the ratio of the surface resistivities of the adhesive layer before and after UV irradiation is within the above-mentioned range, the adhesive layer retains sufficient flexibility even after active energy ray curing, which also facilitates good expansion of the adhesive layer. As a result, the semiconductor processing sheet allows for good pick-up.

[0011] In the above invention (Invention 1), the surface resistivity of the pressure-sensitive adhesive layer before ultraviolet irradiation is 1.0 × 10 8 Ω / □ or more, 1.0×10 13 It is preferably Ω / □ or less (invention 2).

[0012] In the above inventions (Inventions 1 and 2), the surface resistivity of the pressure-sensitive adhesive layer before ultraviolet irradiation is 1.0 × 10 8 Ω / □ or more, 1.0×10 12 It is preferable that the resistance is Ω / □ or less (invention 3).

[0013] In the above inventions (Inventions 1 to 3), the surface resistivity of the pressure-sensitive adhesive layer after ultraviolet irradiation is 1.0 × 10 8 Ω / □ or more, 2.0×10 13 It is preferable that the resistance is Ω / □ or less (invention 4).

[0014] In the above inventions (Inventions 1 to 4), the surface resistivity of the pressure-sensitive adhesive layer after ultraviolet irradiation is 1.0 × 10 8 Ω / □ or more, 1.0×10 12 It is preferable that the resistance is Ω / □ or less (Invention 5).

[0015] In the above inventions (Inventions 1 to 5), the semiconductor processing sheet is preferably used in a semiconductor processing method comprising a lamination process of laminating multiple semiconductor chips on the side of the adhesive layer opposite the substrate, an expanding process of stretching the semiconductor processing sheet on which the semiconductor chips are laminated to separate the semiconductor chips from each other, and a pick-up process of picking up the semiconductor chips individually while they are separated from each other (Invention 6).

[0016] In the above invention (Invention 6), it is preferable that the stacking of the semiconductor chips in the stacking process is carried out by transferring multiple semiconductor chips obtained by dicing a semiconductor wafer or semiconductor package on a dicing sheet from the dicing sheet to the semiconductor processing sheet (Invention 7).

[0017] Secondly, the present invention provides a method for manufacturing a semiconductor device (Invention 8), which comprises a lamination process for laminating multiple semiconductor chips on the adhesive layer side of the semiconductor processing sheet (Inventions 1 to 7 above), an expanding process for stretching the semiconductor processing sheet on which the semiconductor chips are laminated to separate the semiconductor chips from each other, and a pick-up process for picking up the semiconductor chips individually while they are separated from each other.

[0018] Thirdly, the present invention provides a use of the semiconductor processing sheet (above Inventions 1 to 7) for a semiconductor processing method, characterized in that the semiconductor processing method comprises a lamination process of laminating multiple semiconductor chips on the side of the adhesive layer opposite the substrate, an expanding process of stretching the semiconductor processing sheet on which the semiconductor chips are laminated to separate the semiconductor chips from each other, and a pick-up process of picking up the semiconductor chips individually while they are separated from each other (Invention 9). [Effects of the Invention]

[0019] The semiconductor processing sheet according to the present invention can sufficiently space semiconductor chips apart even when dicing is not performed, enabling good pick-up of the semiconductor chips. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described. The semiconductor processing sheet according to this embodiment comprises a substrate and an adhesive layer laminated on one side of the substrate.

[0021] The pressure-sensitive adhesive layer is made of an active energy ray-curable pressure-sensitive adhesive. The pressure-sensitive adhesive has a gel fraction of 85% or more and 97% or less after ultraviolet irradiation. Furthermore, the ratio of the surface resistivity of the pressure-sensitive adhesive layer before ultraviolet irradiation to the surface resistivity of the pressure-sensitive adhesive layer after ultraviolet irradiation (surface resistivity before ultraviolet irradiation / surface resistivity after ultraviolet irradiation) is 0.5 or more.

[0022] The semiconductor processing sheet of this embodiment can be expanded sufficiently by the adhesive layer satisfying the above-mentioned conditions of gel fraction and surface resistivity ratio, and can perform good pickup of semiconductor chips. In particular, the semiconductor processing sheet of this embodiment can be expanded sufficiently even when semiconductor components are not diced on the semiconductor processing sheet, thereby enabling good pickup.

[0023] Usually, when dicing is performed on a semiconductor processing sheet, the adhesive layer is cut along with the semiconductor material, and notches are made in the substrate. Therefore, the diced semiconductor processing sheet is easily stretched in the expanding process because the adhesive layer is finely divided and notches are made in the substrate. In contrast, if dicing is not performed, this effect of making it easier to stretch does not occur. However, the semiconductor processing sheet according to this embodiment can be sufficiently expanded, even though such an effect is not obtained, thereby enabling good pickup.

[0024] In particular, the adhesive layer made of an adhesive satisfying the above-mentioned gel fraction contains a moderate amount of uncured regions inside after irradiation with active energy rays, and therefore the semiconductor processing sheet according to this embodiment including the adhesive layer has good flexibility and can be sufficiently expanded even after irradiation with active energy rays.

[0025] To enable better expansion, the gel fraction is preferably 90% or more, and more preferably 92% or more. The gel fraction is preferably 96.8% or less, and more preferably 96.5% or less. Details of the method for measuring the gel fraction are as shown in the test examples below.

[0026] Furthermore, by satisfying the above-mentioned surface resistivity ratio condition, the semiconductor processing sheet according to this embodiment is likely to achieve good expandability even after active energy ray irradiation. The reasons for this are thought to be, but are not limited to, the following: When the ratio of surface resistivity before and after ultraviolet irradiation is within the above range, the pressure-sensitive adhesive layer can be said to have a surface resistivity that does not change significantly before and after curing by active energy ray irradiation. It has been empirically confirmed that the surface resistivity is correlated with the flexibility of the pressure-sensitive adhesive layer, and when the above ratio is satisfied, the flexibility of the pressure-sensitive adhesive layer can also be said to have a similarly small change before and after active energy ray irradiation. As a result, a certain degree of flexibility is maintained even after the pressure-sensitive adhesive layer is cured by active energy ray irradiation, and good expandability is maintained.

[0027] To enable better expansion, the surface resistivity ratio is preferably 0.6 or more, and more preferably 0.7 or more. The surface resistivity ratio is preferably 0.95 or less, and more preferably 0.9 or less. The surface resistivity ratio can be calculated from the surface resistivities before and after ultraviolet irradiation, and can be specifically obtained as described in the test examples below.

[0028] As described above, the semiconductor processing sheet of this embodiment satisfies the above-mentioned conditions regarding the ratio of gel fraction and surface resistivity, and therefore can be expanded well even without dicing, thereby allowing the semiconductor chips stacked on the semiconductor processing sheet to be sufficiently spaced apart. As a result, the semiconductor processing sheet of this embodiment allows the semiconductor chips to be picked up well.

[0029] 1. Components of semiconductor processing sheets (1) Base material In the semiconductor processing sheet according to this embodiment, the substrate is not particularly limited as long as it exhibits the desired function when the semiconductor processing sheet is used. Since the adhesive layer in this embodiment is composed of an adhesive having active energy ray curability as described above, it is preferable that the substrate has good permeability to active energy rays in order to make it easier for active energy rays to reach the adhesive layer.

[0030] The substrate in this embodiment is preferably a resin film primarily composed of a resin material. Specific examples include polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate; ethylene-vinyl acetate copolymer films; ethylene-(meth)acrylic acid copolymer films, ethylene-methyl(meth)acrylate copolymer films, and other ethylene-(meth)acrylic acid ester copolymer films; polyolefin films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norbornene resin film; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; (meth)acrylic acid ester copolymer films; polyurethane films; polyimide films; polystyrene films; polycarbonate films; and fluororesin films. Examples of polyethylene films include low-density polyethylene (LDPE) film, linear low-density polyethylene (LLDPE) film, and high-density polyethylene (HDPE) film. Modified films such as crosslinked films and ionomer films of these films may also be used. The substrate may also be a laminated film formed by laminating a plurality 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" means both acrylic acid and methacrylic acid. The same applies to other similar terms. Furthermore, "copolymer" also includes the concept of a "polymer" made of a single monomer.

[0031] In addition, the substrate in this embodiment preferably has at least three layers: a surface layer, an intermediate layer, and a back layer. In this case, the material of each layer is not particularly limited as long as it can form those layers, and it is preferable to use, for example, a resin. As the resin, it is preferable to use at least one of a polyolefin resin and a thermoplastic elastomer. Note that the surface layer and the back layer may have different compositions or may have exactly the same composition.

[0032] In this specification, the term "polyolefin resin" refers to a homopolymer or copolymer containing an olefin as a monomer, or a copolymer containing an olefin and a molecule other than an olefin as a monomer, in which the mass ratio of the olefin unit in the polymerized resin is 1.0 mass% or more. Examples of the polyolefin resin include polyethylene and polypropylene. Examples of the polypropylene include homopolypropylene, random polypropylene, and block polypropylene. Examples of the polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, very-low-density polyethylene, and linear low-density polyethylene. These may be used alone or in combination of two or more.

[0033] The thermoplastic elastomer is not particularly limited as long as it is other than the polyolefin-based resins and can be used to form a substrate. Examples of the thermoplastic elastomer include olefin-based elastomers, rubber elastomers, urethane-based elastomers, styrene-based elastomers, acrylic-based elastomers, and vinyl chloride-based elastomers.

[0034] Examples of the olefin-based elastomer include ethylene-propylene copolymer, ethylene-α-olefin copolymer, propylene-α-olefin copolymer, butene-α-olefin copolymer, ethylene-propylene-α-olefin copolymer, ethylene-butene-α-olefin copolymer, propylene-butene-α-olefin copolymer, ethylene-propylene-butene-α-olefin copolymer, etc. These may be used alone or in combination of two or more.

[0035] Examples of the styrene-based elastomer include styrene-conjugated diene copolymers and styrene-olefin copolymers, among which styrene-conjugated diene copolymers are preferred. Examples of the styrene-conjugated diene copolymers include unhydrogenated styrene-conjugated diene copolymers such as styrene-butadiene copolymer, styrene-butadiene-styrene copolymer (SBS), styrene-butadiene-butylene-styrene copolymer, styrene-isoprene copolymer, styrene-isoprene-styrene copolymer (SIS), and styrene-ethylene-isoprene-styrene copolymer; and hydrogenated styrene-conjugated diene copolymers such as styrene-ethylene / propylene-styrene copolymer (SEPS: hydrogenated styrene-isoprene-styrene copolymer) and styrene-ethylene / butylene-styrene copolymer (SEBS: hydrogenated styrene-butadiene copolymer).

[0036] The substrate may contain various additives such as a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a colorant, an infrared absorber, an ultraviolet absorber, an ion scavenger, etc. The content of these additives is not particularly limited, but is preferably set within a range in which the substrate exhibits the desired function.

[0037] The surface of the substrate on which the pressure-sensitive adhesive layer is to be laminated may be subjected to a surface treatment such as a primer treatment, a corona treatment, or a plasma treatment in order to enhance adhesion to the pressure-sensitive adhesive layer.

[0038] The thickness of the substrate can be set appropriately depending on the method in which the semiconductor processing sheet is used, but is usually preferably 20 μm or more, and more preferably 25 μm or more, and is usually preferably 450 μm or less, and more preferably 300 μm or less.

[0039] (2) Adhesive layer The adhesive constituting the adhesive layer in this embodiment is not particularly limited as long as it has active energy ray curability and satisfies the aforementioned conditions of gel fraction and surface resistivity ratio. Examples of such adhesives include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among these, it is preferable to use acrylic adhesives, from the viewpoints that they easily satisfy the aforementioned conditions of gel fraction and surface resistivity ratio and easily exhibit the desired adhesive strength.

[0040] When the adhesive constituting the adhesive layer in this embodiment is an acrylic adhesive, the adhesive composition for forming the adhesive layer may contain, for example, an active energy ray-curable acrylic copolymer as a main component. However, from the viewpoint of easily satisfying the aforementioned conditions of gel fraction and surface resistivity ratio, the adhesive composition preferably contains an acrylic copolymer that is not active energy ray-curable and an active energy ray-curable component. In particular, from the viewpoint of more easily satisfying the aforementioned conditions of gel fraction and surface resistivity ratio, the active energy ray-curable component preferably has four or less functional groups with double bonds and a weight-average molecular weight of 5,000 or more. Note that the weight-average molecular weight (Mw) in this specification, including the weight-average molecular weight, is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0041] In this embodiment, the pressure-sensitive adhesive layer is formed from two components, an acrylic copolymer not having active energy ray curability and an active energy ray curable component, and therefore is more likely to expand favorably than when it is formed from a single component, an acrylic copolymer having active energy ray curability. The reason for this is thought to be, but is not limited to, that when a pressure-sensitive adhesive layer containing the above two independent components is cured by active energy ray irradiation, uncured regions are generated in the pressure-sensitive adhesive layer together with cured regions at an appropriate frequency, making it easier to satisfy the above-mentioned gel fraction.

[0042] In addition, the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer in this embodiment preferably contains an alkylene glycol-based component which is at least one of alkylene glycol, polyalkylene glycol, and derivatives thereof. This makes it easier to achieve better expandability. Although the reason for this is not clear, it is thought that the hydroxyl group of the alkylene glycol-based component moderately inhibits the reaction between the acrylic copolymer and the active energy ray-curable component due to active energy ray irradiation, or the crosslinking between the acrylic copolymers, resulting in the pressure-sensitive adhesive layer having moderate flexibility.

[0043] In addition, the alkylene glycol component can also promote a decrease in adhesive strength to the semiconductor chip when the adhesive layer is cured by active energy ray irradiation. Generally, active energy ray-curable adhesives composed of two components, an acrylic copolymer and an active energy ray-curable component, tend to be less prone to adhesive strength loss during curing than active energy ray-curable adhesives composed of only an acrylic copolymer having an active energy ray-curable group. However, the alkylene glycol component contained in the adhesive composition of this embodiment effectively promotes the above-mentioned decrease in adhesive strength. This, combined with the effect of being able to sufficiently expand as described above, allows the semiconductor processing sheet of this embodiment to achieve better pickup.

[0044] (2-1) Acrylic copolymer not curable with active energy rays The above-mentioned acrylic copolymer not curable with active energy rays is not particularly limited as long as it contains an acrylic monomer as a monomer unit constituting the polymer, and in particular, it is preferably a copolymer of at least a (meth)acrylic acid alkyl ester monomer. The (meth)acrylic acid alkyl ester monomer preferably has an alkyl group with 1 or more carbon atoms, and more preferably 2 or more carbon atoms. Furthermore, the (meth)acrylic acid alkyl ester monomer preferably has an alkyl group with 18 or less carbon atoms, and more preferably 8 or less carbon atoms.

[0045] Specific examples of the (meth)acrylic acid alkyl ester monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate. Among these, it is preferable to use at least one of n-butyl acrylate and methyl acrylate, because this makes it easier to adjust the adhesive strength of the semiconductor processing sheet according to this embodiment to the desired range. The above-mentioned (meth)acrylic acid alkyl ester monomers may be used alone or in combination of two or more.

[0046] The acrylic copolymer preferably contains 50% by mass or more, and more preferably 60% by mass or more, of (meth)acrylic acid alkyl ester monomers as monomer units constituting the polymer, and preferably contains 98% by mass or less, and more preferably 95% by mass or less, of (meth)acrylic acid alkyl ester monomers as monomer units constituting the polymer.

[0047] Furthermore, when the pressure-sensitive adhesive composition contains a crosslinking agent described below, the acrylic copolymer preferably contains a functional group-containing monomer as a monomer unit constituting the polymer, from the viewpoint that the acrylic copolymer is easily crosslinked and the adhesive strength can be easily adjusted to a desired range. Examples of the functional group contained in the functional group-containing monomer include a hydroxy group, a carboxy group, an amino group, a substituted amino group, an epoxy group, etc., and among these, a hydroxy group and a carboxy group are preferred, and a carboxy group is particularly preferred. Note that different types of functional group-containing monomers may be used in combination.

[0048] When a monomer having a carboxy group (carboxy group-containing monomer) is used as the functional group-containing monomer, examples thereof include ethylenically unsaturated carboxylic acids, and specific examples thereof include acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, etc. Among these, acrylic acid is preferred in terms of the reactivity and copolymerizability of the carboxy group. These may be used alone or in combination of two or more.

[0049] When a monomer having a hydroxy group (hydroxy group-containing monomer) is used as the functional group-containing monomer, examples thereof include (meth)acrylic acid hydroxyalkyl esters, and specific examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Among these, 2-hydroxyethyl (meth)acrylate is preferred in terms of the reactivity and copolymerizability of the hydroxy group. These may be used alone or in combination of two or more.

[0050] The acrylic copolymer preferably contains, as a monomer unit constituting the polymer, 0.1% by mass or more of a functional group-containing monomer, particularly preferably 0.5% by mass or more, and even more preferably 1% by mass or more. The acrylic copolymer preferably contains, as a monomer unit constituting the polymer, 30% by mass or less of a functional group-containing monomer, particularly preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0051] The acrylic copolymer may contain, as a monomer unit constituting the polymer, other monomers in addition to the above-mentioned (meth)acrylic acid alkyl ester monomer and functional group-containing monomer.

[0052] Examples of the other monomers include alkoxyalkyl group-containing (meth)acrylic acid esters such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate; (meth)acrylic acid esters having an aliphatic ring such as cyclohexyl (meth)acrylate; (meth)acrylic acid esters having an aromatic ring such as phenyl (meth)acrylate; non-crosslinkable acrylamides such as acrylamide and methacrylamide; (meth)acrylic acid esters having a non-crosslinkable tertiary amino group such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate; vinyl acetate; styrene, etc. These may be used alone or in combination of two or more.

[0053] The acrylic copolymer may be a random copolymer or a block copolymer, and the polymerization method is not particularly limited, and the copolymer may be polymerized by a general polymerization method.

[0054] The weight-average molecular weight (Mw) of the acrylic copolymer in this embodiment is preferably 10,000 or more, particularly preferably 100,000 or more, and even more preferably 200,000 or more. A weight-average molecular weight (Mw) of 10,000 or more makes it easier to adjust the cohesive strength of the pressure-sensitive adhesive layer to a desired range. Furthermore, the weight-average molecular weight (Mw) is preferably 2,000,000 or less, particularly preferably 1,500,000 or less, and even more preferably 1,000,000 or less. A weight-average molecular weight (Mw) of 2,000,000 or less makes it easier to achieve the desired adhesive strength and improves handleability during pressure-sensitive adhesive layer formation.

[0055] (2-2) Active energy ray-curable component As mentioned above, it is preferable that the active energy ray-curable component has four or less functional groups having double bonds and a weight average molecular weight of at least 5000. The active energy ray-curable component has a relatively large weight average molecular weight while having a relatively small number of functional groups, and by using such an active energy ray-curable component, the semiconductor processing sheet has better expandability.

[0056] Examples of the functional group contained in the active energy ray-curable component include an acryloyl group, a vinyl group, etc. The number of functional groups contained in the active energy ray-curable component is preferably 2 or more and 3 or less, from the viewpoint of facilitating expansion.

[0057] Furthermore, from the viewpoint of easier expansion, the weight-average molecular weight of the active energy ray-curable component is preferably 7000 or more, and particularly preferably 8000 or more. Furthermore, from the viewpoint of easier achievement of a desired adhesive strength, the weight-average molecular weight of the active energy ray-curable component is preferably 100,000 or less, particularly preferably 60,000 or less, and further preferably 40,000 or less.

[0058] Preferred examples of the active energy ray-curable component include oligomers or modified products of polyfunctional acrylates. Preferred examples of the oligomers of polyfunctional acrylates include polyfunctional acrylates such as trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, and 1,6-hexanediol diacrylate.

[0059] Examples of the modified product include urethane modified products, epoxy modified products, ester modified products, etc. Among these, urethane modified products are preferred from the viewpoint of ease of adjusting the weight average molecular weight and the number of functional groups to the above-mentioned ranges.

[0060] The urethane-modified product is preferably obtained by reacting the polyfunctional acrylate with a polyisocyanate compound. Examples of the polyisocyanate compound include alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; and aliphatic polyisocyanates such as hexamethylene diisocyanate. Among these, alicyclic polyisocyanates are preferred, and isophorone diisocyanate is particularly preferred.

[0061] The content of the active energy ray-curable component in the pressure-sensitive adhesive composition in this embodiment is preferably 10 parts by mass or more, particularly preferably 20 parts by mass or more, and even more preferably 30 parts by mass or more, relative to 100 parts by mass of the above-mentioned acrylic copolymer. Furthermore, the content is preferably 300 parts by mass or less, particularly preferably 200 parts by mass or less, and even more preferably 150 parts by mass or less. By having the content of the active energy ray-curable component within the above range, the pressure-sensitive adhesive layer after irradiation with active energy rays has a better distribution of cured and uncured regions, making it easier for the semiconductor processing sheet to expand.

[0062] (2-3) Alkylene glycol-based components As mentioned above, it is preferable to use at least one of alkylene glycol, polyalkylene glycol and derivatives thereof as the alkylene glycol-based component.

[0063] Examples of the alkylene glycol include ethylene glycol, propylene glycol, butylene glycol, tetramethylene glycol, and glycerin.

[0064] Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, poly(ethylene-propylene) glycol, polybutylene glycol, polyglycerin, etc. Among these, it is preferable to use polyethylene glycol, from the viewpoint of easily obtaining the above-mentioned effect of reducing adhesive strength and the effect of achieving good expansion.

[0065] The weight-average molecular weight of the polyalkylene glycol is preferably 30,000 or less, particularly preferably 20,000 or less, and more preferably 10,000 or less. When the weight-average molecular weight is within this range, the adhesive strength is easily reduced after irradiation with active energy rays, and the semiconductor processing sheet is easily expanded. The lower limit of the weight-average molecular weight may be, for example, 200 or less, particularly 150 or less, or even 100 or less.

[0066] The derivative is represented by the general formula X-(O-Ar)n-OY, where X and Y are, for example, hydrogen atoms, modified rosin esters, benzoic acid esters, stearic acid, etc., Ar is, for example, a hydrocarbon such as CH2 (methylene), C2H4 (ethylene), or C3H6 (propylene), and n is an integer of 1 to 200. A preferred example of the derivative is an alkylene glycol-modified rosin ester.

[0067] The alkylene glycol-modified rosin ester is not particularly limited, but is preferably one obtained by, for example, an esterification reaction of rosin, a polyalkylene glycol monoalkyl ether, a polyhydric alcohol, and an α,β-unsaturated carboxylic acid.

[0068] The weight-average molecular weight of the alkylene glycol-modified rosin ester is preferably 1,000 or more, particularly preferably 2,000 or more, and even more preferably 3,000 or more. The weight-average molecular weight is preferably 1,000,000 or less, more preferably 100,000 or less, particularly preferably 50,000 or less, and even more preferably 10,000 or less. Having the weight-average molecular weight within this range facilitates sufficient reduction in adhesive strength after active energy ray irradiation, and facilitates favorable expansion of the semiconductor processing sheet.

[0069] The content of the alkylene glycol component in the pressure-sensitive adhesive composition in this embodiment is preferably 0.005 parts by mass or more, particularly preferably 0.01 parts by mass or more, and even more preferably 0.05 parts by mass or more, relative to 100 parts by mass of the above-mentioned acrylic copolymer. Furthermore, the content is preferably 30 parts by mass or less, particularly preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less. By having the alkylene glycol component content within the above range, the adhesive strength is easily reduced sufficiently after active energy ray irradiation, and the semiconductor processing sheet is easily expanded.

[0070] (2-4) Crosslinking agent The pressure-sensitive adhesive composition of this embodiment preferably contains a crosslinking agent. By including a crosslinking agent in the pressure-sensitive adhesive composition, the acrylic copolymer in the pressure-sensitive adhesive layer is crosslinked, allowing for the formation of a favorable three-dimensional network structure. This makes it easier for the pressure-sensitive adhesive layer of this embodiment to satisfy the gel fraction requirement described above. Furthermore, the cohesive strength of the resulting pressure-sensitive adhesive is further improved, effectively suppressing the occurrence of adhesive residue on the adherend separated from the semiconductor processing sheet after irradiation with active energy rays. When the pressure-sensitive adhesive composition contains a crosslinking agent, the acrylic copolymer preferably contains the above-mentioned functional group-containing monomer as a monomer unit constituting the polymer, and in particular, preferably contains a functional group-containing monomer having a functional group highly reactive with the crosslinking agent used.

[0071] Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, amine-based crosslinking agents, melamine-based crosslinking agents, aziridine-based crosslinking agents, hydrazine-based crosslinking agents, aldehyde-based crosslinking agents, oxazoline-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, and ammonium salt-based crosslinking agents. These crosslinking agents can be selected depending on the functional groups derived from the functional group-containing monomers contained in the acrylic copolymer. These crosslinking agents can be used alone or in combination of two or more.

[0072] The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; and biuret and isocyanurate forms thereof, as well as adducts thereof that are reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among these, trimethylolpropane-modified aromatic polyisocyanates, particularly trimethylolpropane-modified tolylene diisocyanate, are preferred.

[0073] When the pressure-sensitive adhesive composition of this embodiment contains a crosslinking agent, the content of the crosslinking agent in the pressure-sensitive adhesive composition is preferably 1 part by mass or more, particularly preferably 3 parts by mass or more, relative to 100 parts by mass of the above-mentioned acrylic copolymer. Furthermore, this content is preferably 20 parts by mass or less, particularly preferably 15 parts by mass or less. A crosslinking agent content of 1 part by mass or more facilitates improving the cohesive strength of the pressure-sensitive adhesive layer after irradiation with active energy rays, thereby making it possible to effectively suppress adhesive residue. Furthermore, a crosslinking agent content of 20 parts by mass or less ensures an appropriate degree of crosslinking, making it easier for the pressure-sensitive adhesive layer to exhibit the desired adhesive strength.

[0074] (2-5) Photopolymerization initiator The pressure-sensitive adhesive composition in the present embodiment preferably contains a photopolymerization initiator. By containing the photopolymerization initiator in the pressure-sensitive adhesive composition, it is possible to reduce the polymerization curing time and the light irradiation dose when the pressure-sensitive adhesive layer is cured by irradiating it with active energy rays.

[0075] Examples of photopolymerization initiators include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}, and 2,2-dimethoxy-1,2-diphenylethan-1-one. Among these, 1-hydroxycyclohexyl phenyl ketone is preferably used. The above-mentioned photopolymerization initiators may be used alone or in combination of two or more kinds.

[0076] When the pressure-sensitive adhesive composition of this embodiment contains a photopolymerization initiator, the content of the photopolymerization initiator in the pressure-sensitive adhesive composition is preferably 0.1 parts by mass or more, and more preferably 1 part by mass or more, relative to 100 parts by mass of the above-mentioned acrylic copolymer. Furthermore, the content is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less. By having the content of the photopolymerization initiator within the above range, the pressure-sensitive adhesive layer can be efficiently cured by irradiation with active energy rays, which makes it easier to effectively reduce the adhesive strength of the semiconductor processing sheet to the adherend.

[0077] (2-6) Other ingredients The adhesive composition of this embodiment can contain desired additives, such as silane coupling agents, antistatic agents, tackifiers, antioxidants, light stabilizers, softeners, fillers, refractive index adjusters, etc., as long as they do not impair the effects of the semiconductor processing sheet of this embodiment. Note that the polymerization solvents and dilution solvents described below are not included in the additives that make up the adhesive composition.

[0078] (2-7) Method for preparing pressure-sensitive adhesive composition The pressure-sensitive adhesive composition in the present embodiment can be produced by producing an acrylic copolymer, and mixing the obtained acrylic copolymer with an active energy ray-curable component, an alkylene glycol-based component, and, if desired, a crosslinking agent, a photopolymerization initiator, and additives.

[0079] The acrylic copolymer can be produced by polymerizing a mixture of monomers constituting the polymer by a conventional radical polymerization method. The polymerization is preferably carried out by a solution polymerization method using a polymerization initiator as desired. Examples of polymerization solvents include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more of them may be used in combination.

[0080] Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of the azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane].

[0081] Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl)peroxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, (3,5,5-trimethylhexanoyl)peroxide, dipropionyl peroxide, and diacetyl peroxide.

[0082] In the polymerization step, the weight average molecular weight of the resulting polymer can be adjusted by adding a chain transfer agent such as 2-mercaptoethanol.

[0083] Once the acrylic copolymer is obtained, an active energy ray curable component, an alkylene glycol component, and, if desired, a crosslinking agent, a photopolymerization initiator, other additives, and a dilution solvent are added to the acrylic copolymer solution, and the mixture is thoroughly mixed to obtain a coating solution of the pressure-sensitive adhesive composition. Note that, when any of the above components is used in a solid state, or when precipitation occurs when mixed with other components in an undiluted state, the component may be dissolved or diluted alone in a dilution solvent before being mixed with other components.

[0084] Examples of the dilution solvent include aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; alcohols such as methanol, ethanol, propanol, butanol, and 1-methoxy-2-propanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; and cellosolve-based solvents such as ethyl cellosolve.

[0085] The concentration and viscosity of the coating solution prepared in this manner are not particularly limited as long as they are within a range that allows coating, and can be appropriately selected depending on the situation. For example, the pressure-sensitive adhesive composition is diluted so that its concentration is 10% by mass or more and 60% by mass or less. Note that the addition of a dilution solvent or the like is not a necessary condition for obtaining the coating solution, and as long as the pressure-sensitive adhesive composition has a viscosity that allows coating, the addition of a dilution solvent is not necessary. In this case, the pressure-sensitive adhesive composition becomes a coating solution in which the polymerization solvent for the acrylic copolymer is used as the dilution solvent.

[0086] (2-8) Thickness of adhesive layer In this embodiment, the thickness of the adhesive layer is preferably 1 μm or more, particularly preferably 3 μm or more, and even more preferably 5 μm or more. Having a thickness of 1 μm or more makes it easier for the semiconductor processing sheet to exhibit good adhesive strength and to hold the adherend well. Furthermore, the thickness is preferably 50 μm or less, particularly preferably 30 μm or less, and even more preferably 20 μm or less. Having a thickness of 20 μm or less makes it easier for the adhesive layer to expand sufficiently.

[0087] (3) Release sheet In the semiconductor processing sheet according to this embodiment, a release sheet may be laminated on the adhesive surface of the adhesive layer to protect the adhesive surface until it is attached to a semiconductor member. The release sheet may have any configuration, and examples include plastic films that have been treated with a release agent. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. Silicone-based, fluorine-based, and long-chain alkyl-based release agents can be used as release agents, with silicone-based release agents being preferred because they are inexpensive and provide stable performance. The thickness of the release sheet is not particularly limited, but is typically 20 μm or more and 250 μm or less.

[0088] 2. Physical properties of semiconductor processing sheets (1) Adhesive strength In the semiconductor processing sheet of this embodiment, the adhesive strength to a silicon wafer (the mirror surface of a mirror-finished silicon wafer, the same applies below) before active energy ray irradiation is preferably 500 mN / 25 mm or more, more preferably 1000 mN / 25 mm or more, particularly preferably 1500 mN / 25 mm or more, and even more preferably 2000 mN / 25 mm or more. In the semiconductor processing sheet of this embodiment, the adhesive layer is composed of an adhesive having active energy ray curability, making it easy to achieve the above-mentioned adhesive strength before active energy ray irradiation. Furthermore, since the adhesive strength to a silicon wafer before active energy ray irradiation is 500 mN / 25 mm or more, it becomes easy to fix the semiconductor chip to the semiconductor processing sheet well and easily prevent the semiconductor chip from unintentionally falling off. Although there are no particular limitations on the upper limit of the adhesive strength, it is preferably 20,000 mN / 25 mm or less, particularly preferably 15,000 mN / 25 mm or less, and even more preferably 10,000 mN / 25 mm or less. Details of the method for measuring the adhesive strength are as described in the test examples below.

[0089] Furthermore, in the semiconductor processing sheet according to this embodiment, the adhesive strength to the silicon wafer after active energy ray irradiation is preferably 1500 mN / 25 mm or less, more preferably 600 mN / 25 mm or less, and even more preferably 300 mN / 25 mm or less. In the semiconductor processing sheet according to this embodiment, the adhesive layer is composed of an adhesive having active energy ray curability, which makes it easier to achieve the above-mentioned adhesive strength after active energy ray irradiation. Furthermore, an adhesive strength to the silicon wafer of 1500 mN / 25 mm or less after active energy ray irradiation facilitates peeling of the semiconductor chip from the semiconductor processing sheet and effectively suppresses the occurrence of adhesive residue. Furthermore, the adhesive strength to the silicon wafer after active energy ray irradiation is preferably 1 mN / 25 mm or more, more preferably 10 mN / 25 mm or more, and even more preferably 30 mN / 25 mm or more. This makes it easier to suppress unintended separation or detachment of the semiconductor chip after active energy ray irradiation. Details of the method for measuring the adhesive strength are as described in the test examples below.

[0090] (2)Surface resistivity In the semiconductor processing sheet according to this embodiment, the surface resistivity of the adhesive layer before ultraviolet irradiation is 1.0 × 10 13 It is preferably Ω / □ or less, and particularly 5.0×10 12 It is preferably Ω / □ or less, and more preferably 1.0×10 12 It is preferable that the surface resistivity is Ω / □ or less. When the surface resistivity is in this range, when the semiconductor processing sheet according to this embodiment is peeled off from the adherend, the adherend can be prevented from being destroyed by peeling electrification. The lower limit of the surface resistivity of the pressure-sensitive adhesive layer before ultraviolet irradiation is not particularly limited, and can be, for example, 1.0 × 10 8 The surface resistivity may be Ω / □ or more. Details of the method for measuring the surface resistivity are as described in the test examples below.

[0091] In addition, in the semiconductor processing sheet according to this embodiment, the surface resistivity of the pressure-sensitive adhesive layer after ultraviolet irradiation is 2.0 × 10 13 It is preferable that the resistance is Ω / □ or less, and 1.0×10 13 It is more preferable that the resistance is Ω / □ or less, and particularly 5.0×10 12 It is preferably Ω / □ or less, and more preferably 1.0×10 12 It is preferable that the surface resistivity is Ω / □ or less. When the surface resistivity is in this range, when the semiconductor processing sheet according to this embodiment is peeled off from the adherend, the adherend can be prevented from being destroyed by peeling electrification. The lower limit of the surface resistivity of the pressure-sensitive adhesive layer after ultraviolet irradiation is not particularly limited, and can be, for example, 1.0 × 10 8 The surface resistivity may be Ω / □ or more. Details of the method for measuring the surface resistivity are as described in the test examples below.

[0092] 3. Manufacturing method of semiconductor processing sheet The method for manufacturing the semiconductor processing sheet according to this embodiment is not particularly limited, and it is preferably manufactured by laminating a pressure-sensitive adhesive layer on one side of a substrate.

[0093] The adhesive layer can be laminated on one side of the substrate by a known method. For example, it is preferable to transfer the adhesive layer formed on a release sheet to one side of the substrate. In this case, a coating liquid containing an adhesive composition constituting the adhesive layer and, optionally, a solvent or dispersion medium is prepared, and the coating liquid is applied to the release-treated surface of the release sheet (hereinafter sometimes referred to as the "release surface") using a die coater, curtain coater, spray coater, slit coater, knife coater, applicator, or the like to form a coating film, and the coating film is dried to form the adhesive layer. The properties of the coating liquid are not particularly limited as long as it can be applied, and it may contain the components for forming the adhesive layer as a solute or as a dispersoid. The release sheet in this laminate may be peeled off as a processing material, or it may be used to protect the adhesive surface of the adhesive layer until the semiconductor processing sheet is attached to the adherend.

[0094] When the coating solution for forming the adhesive layer contains a crosslinking agent, the crosslinking reaction between the acrylic copolymer in the coating film and the crosslinking agent can be promoted by changing the drying conditions (temperature, time, etc.) or by separately providing a heat treatment, thereby forming a crosslinked structure with the desired density in the adhesive layer. To promote this crosslinking reaction sufficiently, after laminating the adhesive layer on the substrate by the above-mentioned method, the resulting work processing sheet can be cured by, for example, leaving it in an environment of 23°C and a relative humidity of 50% for several days.

[0095] Instead of transferring the PSA layer formed on the release sheet to one side of the substrate as described above, the PSA layer may be formed directly on the substrate. In this case, the PSA layer is formed by applying the coating liquid for forming the PSA layer to one side of the substrate to form a coating film, and then drying the coating film.

[0096] 4.How to use semiconductor processing sheets The semiconductor processing sheet according to this embodiment can be used for processing semiconductor components. That is, after the adhesive surface of the semiconductor processing sheet according to this embodiment is attached to a semiconductor component, the semiconductor component can be processed on the semiconductor processing sheet. Examples of semiconductor components include semiconductor wafers and semiconductor packages.

[0097] As described above, the semiconductor processing sheet according to this embodiment can sufficiently separate the semiconductor chips from each other by the expanding process even when dicing is not performed (i.e., when the adhesive layer is not cut together with the semiconductor member), thereby enabling good pick-up of the semiconductor chips. Therefore, the semiconductor processing sheet according to this embodiment is suitable for use in a semiconductor processing method in which the expanding process and pick-up process are performed without performing a dicing process on the semiconductor processing sheet.

[0098] More specifically, the semiconductor processing sheet of this embodiment is suitable for use in a semiconductor processing method that includes a lamination process in which semiconductor chips are laminated on the side of the adhesive layer opposite the substrate, an expansion process in which the semiconductor processing sheet on which the semiconductor chips are laminated is stretched to separate the semiconductor chips from each other, and a pick-up process in which the semiconductor chips are individually picked up while they are separated from each other.

[0099] In the stacking process, the semiconductor chips stacked on the semiconductor processing sheet according to this embodiment may be obtained by dicing a semiconductor wafer or semiconductor package on a dicing sheet in advance. The semiconductor chips thus obtained can be stacked on the semiconductor processing sheet according to this embodiment by, for example, transferring them from the dicing sheet. The specific methods for these dicing and transfer processes can be performed in the same manner as conventional methods. Furthermore, the expanding process and the pick-up process can also be performed using conventional methods.

[0100] The semiconductor processing method can also include an irradiation step of irradiating the adhesive layer with active energy rays. The irradiation step is preferably performed between the lamination step and the expansion step, or between the expansion step and the pick-up step. In the irradiation step, the adhesive layer is irradiated with active energy rays to harden the adhesive layer, thereby reducing the adhesive strength to the semiconductor chip. This makes it easier to separate the semiconductor chip from the adhesive layer in the pick-up step, facilitating successful pick-up. Typically, ultraviolet rays, electron beams, etc. are used as the active energy rays, with ultraviolet rays being particularly preferred because they are easy to handle. Conventional conditions for irradiating the active energy rays can be used.

[0101] The semiconductor processing sheet according to this embodiment may be used not only for the semiconductor processing method described above, but also for back grinding and dicing.

[0102] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0103] For example, another layer may be provided between the substrate and the pressure-sensitive adhesive layer, or on the surface of the substrate opposite to the pressure-sensitive adhesive layer. [Example]

[0104] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0105] Example 1 (1) Preparation of the substrate 30 parts by mass of random polypropylene resin (manufactured by Japan Polypropylene Corporation, product name "Novatec FX3B"), 45 parts by mass of olefin-based thermoplastic elastomer (manufactured by Japan Polypropylene Corporation, product name "Wellnex RFX4V"), and 25 parts by mass of antistatic agent (manufactured by Sanyo Chemical Industry Co., Ltd., product name "Pelectron PVH", melt flow rate: 9.8 g / 10 min) were dried and then kneaded in a twin-screw kneader to obtain pellets for the surface layer.

[0106] Furthermore, 28 parts by mass of random polypropylene resin (manufactured by Japan Polypropylene Corporation, product name "Novatec FX3B"), 39 parts by mass of olefin-based thermoplastic elastomer (manufactured by Japan Polypropylene Corporation, product name "Wellnex RFX4V"), and 33 parts by mass of styrene-based thermoplastic elastomer (manufactured by Asahi Kasei Corporation, product name "Tuftec H1041", styrene-ethylene / butylene-styrene copolymer, styrene ratio: 30 wt%) were dried and then kneaded in a twin-screw kneader to obtain pellets for the intermediate layer.

[0107] Furthermore, 70 parts by mass of an olefin-based thermoplastic elastomer (manufactured by Japan Polypropylene Corporation, product name "Wellnex RFX4V") and 30 parts by mass of an antistatic agent (manufactured by Sanyo Chemical Industry Co., Ltd., product name "Pelectron PVH", melt flow rate: 9.8 g / 10 min) were each dried and then kneaded in a twin-screw kneader to obtain pellets for the back layer.

[0108] The three pellets obtained as described above were co-extruded using a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name "Labo Plastomill") and fed into the hopper of a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., screw diameter: 50 mm, screw effective length L / D: 32). The extruder temperature was set to C1: 210 ° C, C2: 230 ° C, C3: 230 ° C, C4: 230 ° C, C5: 230 ° C, and extruded from a 550 mm wide T-die (temperature setting: 230 ° C, lip opening: 0.3 mm). The extruded molten resin was cooled and solidified on a winder equipped with a cooling roll (cooling roll: 700 mm wide x φ350 mm, roll temperature: 30 ° C), and a three-type three-layer structure substrate was obtained, consisting of a 2 μm thick surface layer, a 64 μm thick middle layer, and a 14 μm thick back layer laminated in order.

[0109] (2) Preparation of alkylene glycol-based components 711 g of gum rosin, 107 g of glycerin, 189 g of fumaric acid, 2100 g of polypropylene glycol with a weight-average molecular weight of 1000, and 150 g of xylene were charged into a flask, purged with nitrogen, and then heated at 280°C for 13 hours with stirring. The xylene was then removed under reduced pressure at 200°C for 20 minutes. The contents were then removed from the flask and cooled to room temperature to solidify, yielding an alkylene glycol-modified rosin ester as the alkylene glycol component.

[0110] (3) Preparation of adhesive composition 75 parts by mass of n-butyl acrylate, 20 parts by mass of methyl acrylate, and 5 parts by mass of acrylic acid were polymerized by solution polymerization to obtain a (meth)acrylic acid ester copolymer as an acrylic copolymer. The weight average molecular weight (Mw) of the (meth)acrylic acid ester copolymer was measured by the method described below and was found to be 600,000.

[0111] 100 parts by mass (solid content equivalent, the same applies hereinafter) of the obtained (meth)acrylic acid ester copolymer, 48 parts by mass of a urethane acrylate (manufactured by Daicel-Allnex Corporation, product name "KRM8961") having 2 to 3 functional groups and a weight average molecular weight of 10,000 as an active energy ray-curable component, 2 parts by mass of the alkylene glycol-modified rosin ester (manufactured by BASF, product name "Omnirad 184") as an alkylene glycol-based component prepared in the above step (2), 3 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, product name "Omnirad 184") as a photopolymerization initiator, and 4.5 parts by mass of a polyisocyanate-based crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate L") as a crosslinking agent were mixed in ethyl acetate as a solvent to obtain a coating liquid of a pressure-sensitive adhesive composition (solid content concentration: 25% by mass).

[0112] (4) Formation of adhesive layer A coating solution of the above adhesive composition was applied to the release surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031") consisting of a 38 μm thick polyethylene terephthalate (PET) film with a silicone-based release agent layer formed on one side thereof, and the sheet was dried by heating to form a 5 μm thick adhesive layer on the release sheet.

[0113] (5) Preparation of semiconductor processing sheets The exposed surface of the adhesive layer formed in step (4) above was bonded to the surface of the surface layer of the substrate prepared in step (1) above to obtain a semiconductor processing sheet with a release sheet.

[0114] (6) Measurement of weight-average molecular weight (Mw) of (meth)acrylic acid ester copolymer The weight average molecular weight (Mw) of the (meth)acrylic acid ester copolymer is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement). <Measurement conditions> GPC measuring device: Tosoh HLC-8020 GPC columns (passed in the following order): Tosoh Corporation TSK guard column HXL-H TSK gel GMHXL (×2) TSK gel G2000HXL Measurement solvent: tetrahydrofuran ·Measurement temperature: 40℃

[0115] [Examples 2 to 15 and Comparative Examples 1 to 11] A semiconductor processing sheet was produced in the same manner as in Example 1, except that the type and content of the active energy ray-curable component, the type and content of the alkylene glycol-based component, and the content of the crosslinking agent were changed as shown in Table 1.

[0116] Details of the abbreviations and other information listed in Table 1 are as follows: [Active energy ray-curable component] KRM8961: Urethane acrylate with 2 to 3 functional groups and a weight-average molecular weight of 10,000 (manufactured by Daicel Allnex Corporation, product name "KRM8961") EBECRYL230: A urethane acrylate with two functional groups and a weight-average molecular weight of 5,000 (manufactured by Daicel-Allnex Corporation, product name "EBECRYL230") PN-3660: A urethane acrylate with four functional groups and a weight-average molecular weight of 7,000 (POLYNETRON, product name "POLYGOMER PN-3660") UA-306H: A urethane acrylate with 5 to 7 functional groups and a weight-average molecular weight of 1,000 (manufactured by Kyoeisha Chemical Co., Ltd., product name "UA-306H") PN-3630: A urethane acrylate with six functional groups and a weight-average molecular weight of 2,500 (manufactured by POLYNETRON, product name "POLYGOMER PN-3630") [Alkylene glycol-based ingredients] PEG3000: Polyethylene glycol (Sigma-Aldrich, product name "PEG3000", weight-average molecular weight: 2700-3300) PTMG3000: Polytetramethylene ether glycol (Mitsubishi Chemical Corporation, product name "PTMG3000", weight-average molecular weight: 2900)

[0117] [Test Example 1] (Measurement of adhesive strength) The semiconductor processing sheets produced in the examples and comparative examples were left to stand for one week in an environment of 23°C temperature and 50% humidity, and then cut into a size of 25 mm width and 300 mm length.

[0118] The release sheet was then peeled off, and the exposed surface of the adhesive layer was placed on the mirror surface of a 6-inch silicon wafer, and the wafer was laminated by applying a load by rolling a 2 kg roller back and forth once, and left for 20 minutes. This was used as a laminate for adhesive strength measurement.

[0119] The adhesive strength (mN / 25 mm) of the resulting laminate for adhesive strength measurement was measured by peeling the semiconductor processing sheet from the silicon wafer at a peeling speed of 300 mm / min and a peeling angle of 180° using the 180° peel method in accordance with JIS Z0237: 2009. This measured value is the adhesive strength before UV irradiation and is shown in Table 1.

[0120] In addition, the adhesive strength measurement laminate obtained in the same manner as above was subjected to ultraviolet (UV) irradiation (illuminance: 200 mW / cm) under nitrogen using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") on the substrate side of the semiconductor processing tape. 2 ,Light amount: 180mJ / cm 2 ) was performed to cure the adhesive layer. Thereafter, the adhesive strength (mN / 25 mm) was measured in the same manner as above. This measured value is shown in Table 1 as the adhesive strength after UV irradiation.

[0121] [Test Example 2] (Measurement of expansion amount) The release sheet was peeled off from the semiconductor processing sheet (hereinafter sometimes referred to as "dicing sheet") produced in Example 1, and the exposed surface of the adhesive layer was attached to the polished surface of a 6-inch silicon wafer (thickness: 350 μm, polished at #2000) using a tape mounter (manufactured by Lintec Corporation, product name "RAD-2500m / 12"). Next, the outer periphery of the exposed surface of the dicing sheet (the area where the 6-inch silicon wafer was not present) was fixed to a ring frame, and the 6-inch silicon wafer was diced under the following conditions. <Dicing conditions> Dicing equipment: DISCO, product name "DFD-6362" Blade: DISCO, product name "NBC-ZH2050-27HECC" Blade rotation speed: 30,000 rpm ·Cutting speed: 50mm / min Depth of cut: 20μm Dicing size: 1mm x 1mm

[0122] After dicing, the substrate side of the dicing sheet was irradiated with ultraviolet light (UV) (illuminance: 200 mW / cm) under nitrogen using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000"). 2 ,Light amount: 180mJ / cm 2 ) was carried out to cure the adhesive layer.

[0123] The chips obtained by the dicing were then transferred to the exposed surface of the adhesive layer of the semiconductor processing sheet produced in Examples and Comparative Examples by peeling off the release sheet from the dicing sheet using a laminator.Furthermore, the outer periphery of the exposed surface of the semiconductor processing sheet (the area where no chips were present) was fixed to a ring frame.

[0124] Then, the substrate side of the semiconductor processing sheet was irradiated with ultraviolet (UV) light (illuminance: 200 mW / cm ) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") under nitrogen. 2 ,Light amount: 180mJ / cm 2 ) was carried out to cure the adhesive layer.

[0125] Next, the semiconductor processing sheet with the stacked chips was placed in an expanding device (JCM, product name "ME-300B", semi-automatic expander). Five pairs of two adjacent chips were selected from the chips stacked on the semiconductor processing sheet. These five pairs of chips were one pair located in the center of the semiconductor processing sheet when viewed from above, the other four pairs located on the periphery of the semiconductor processing sheet, above, below, left, and right of the center. The distance (μm) between these five pairs of chips was measured, and the average value was used as the chip spacing before expansion. The semiconductor processing sheet was then expanded at a speed of 1 mm / sec with a pull-down distance of 10 mm. In the expanded state, the distance (μm) between the five pairs of chips selected above was measured again, and the average value was used as the chip spacing after expansion.

[0126] The difference in chip spacing before and after expansion was calculated by subtracting the chip spacing before expansion from the chip spacing after expansion obtained as described above, and this was taken as the expansion amount (μm). The measurements are shown in Table 1.

[0127] [Test Example 3] (Measurement of interlayer adhesion) The semiconductor processing sheets manufactured in the examples and comparative examples were irradiated with ultraviolet (UV) light (illuminance: 200 mW / cm) from the substrate side in air using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") with the release sheet still attached. 2 ,Light amount: 180mJ / cm 2 ) was carried out to cure the adhesive layer.

[0128] The release sheet was then removed from the semiconductor processing sheet to expose the cured adhesive layer. 11 vertical and 11 horizontal lines were cut into the adhesive layer at 5 mm intervals, creating a grid pattern (100 squares). The depth of the cuts was adjusted so that they completely cut into the adhesive layer (5 μm) but did not cut deeply into the substrate (80 μm) (specifically, 5 μm or more and less than 50 μm).

[0129] Then, cellophane adhesive tape (manufactured by Nichiban Co., Ltd., product name "Cellotape (registered trademark)") was applied to the surface of the adhesive layer, and after leaving it to stand for 20 minutes at 23°C and 50% RH (relative humidity), while holding the semiconductor processing sheet with one hand, the edge of the cellophane adhesive tape was held with the other hand and pulled in a direction perpendicular to the semiconductor processing sheet, and instantly peeled off from the surface of the adhesive layer.

[0130] After peeling off the cellophane adhesive tape, the check marks on the adhesive layer of the semiconductor processing sheet were visually inspected, and the number of squares where peeling between the adhesive layer and the substrate had occurred was counted. The results are shown in Table 1.

[0131] The number of peeled squares is an index of the interlayer adhesion between the adhesive layer and the substrate in the semiconductor processing sheet after ultraviolet irradiation. That is, the fewer the number of peeled squares, the better the interlayer adhesion between the adhesive layer and the substrate.

[0132] [Test Example 4] (Measurement of surface resistivity) The semiconductor processing sheets manufactured in the examples and comparative examples were cut into a size of 100 mm x 100 mm, and these were used as samples for measuring surface resistivity (before UV irradiation).

[0133] In addition, similarly cut semiconductor processing sheets were irradiated with ultraviolet (UV) light (illuminance: 200 mW / cm) in air using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") with the release sheet still attached. 2 ,Light amount: 180mJ / cm 2) was carried out to cure the adhesive layer, and this was used as a sample for measuring surface resistivity (after UV irradiation).

[0134] The two types of surface resistivity measurement samples obtained as described above were conditioned at 23°C and 50% relative humidity for 24 hours, and then the release sheet was peeled off to expose the pressure-sensitive adhesive layer, and the surface resistivity (Ω / □) of the exposed surface was measured using a DIGITAL ELECTROMETER (manufactured by ADVANTEST) at an applied voltage of 100 V. The respective results are shown in Table 1.

[0135] [Test Example 5] (Tensile measurement with tip) The semiconductor processing sheets prepared in the examples and comparative examples were cut to a size of 10 mm × 140 mm. The release sheet was peeled off from the cut semiconductor processing sheet, and the exposed surface of the adhesive layer was exposed. Diced chips (10 × 100 chips, each 1 mm × 1 mm in size) were transferred to the exposed surface using a laminator in the same manner as in Test Example 2.

[0136] Next, the substrate side of the semiconductor processing sheet on which the chips were stacked was irradiated with ultraviolet (UV) light (illuminance: 200 mW / cm ) under nitrogen using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000"). 2 ,Light amount: 180mJ / cm 2 ) was carried out to cure the adhesive layer.

[0137] Next, the semiconductor processing sheet with chips after the adhesive layer was cured was placed in a tensile tester (manufactured by Orientec Co., Ltd., product name "Tensilon RTA-T-2M"), and the distance (μm) between the two chips at the center of the semiconductor processing sheet was measured, which was used as the chip spacing before the tensile test.

[0138] Thereafter, in accordance with JIS K7161:2014, a tensile test was performed using the above tensile tester at a temperature of 23°C and a relative humidity of 50%, with a chuck distance of 100 mm and a tensile speed of 200 mm / min, until the chuck distance reached 110 mm and was held there for 4 minutes.The distance (μm) between the two chips whose chip distance was measured as described above was then measured and used as the chip distance after the tensile test.

[0139] The difference in tip spacing (μm) before and after the tensile test was obtained by subtracting the tip spacing before the tensile test from the tip spacing after the tensile test obtained as described above. Furthermore, the same measurement was performed on two different tips, and the average value of the differences in the two tip spacings obtained was calculated. This is shown in Table 1 as the tip spacing (μm) for the tensile measurement with the tip.

[0140] The two sets of chips (four chips in total) selected for the above measurements were selected so that they were aligned in a straight line parallel to the extrusion direction (MD direction) during molding of the semiconductor processing sheet substrate.

[0141] Test Example 6 (Measurement of gel fraction) A laminate was obtained in the same manner as in step (4) of Example 1, in which a 5 μm-thick adhesive layer was formed on a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031"), and the release surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET382150") was then attached to the adhesive layer side of the laminate to obtain a sheet for measuring gel fraction.

[0142] The obtained gel fraction measurement sheet was cut into a size of 80 mm × 80 mm, and one side of the sheet was irradiated with ultraviolet (UV) light (illuminance: 200 mW / cm) in air using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000"). 2 ,Light amount: 180mJ / cm 2 ) was carried out to harden the adhesive layer.

[0143] Next, the release sheets on both sides were removed to obtain a cured adhesive layer (adhesive), which was then wrapped in a polyester mesh (mesh count: 200 mesh / inch), and the mass of the adhesive alone was weighed using a precision balance. This mass was designated M1.

[0144] Next, the adhesive wrapped in the mesh was immersed in an ethyl acetate solvent at room temperature (23°C) for 24 hours. The mesh containing the adhesive was then removed from the ethyl acetate solvent, and the adhesive was air-dried for 24 hours at 23°C and 50% RH, and then dried in an oven at 80°C for 12 hours. The mass of the adhesive alone after drying was then weighed using a precision balance. This mass was designated M2.

[0145] The gel fraction (%) of the pressure-sensitive adhesive after UV irradiation was then calculated by (M2 / M1) × 100. The results are shown in Table 1.

[0146] [Table 1]

[0147] As can be seen from Table 1, the semiconductor processing sheets obtained in the examples had a larger expansion amount and a larger chip spacing value in the chip-attached tensile measurement than the comparative examples. Therefore, it was found that the semiconductor processing sheets obtained in the examples can be expanded well even without dicing. [Industrial Applicability]

[0148] The semiconductor processing sheet of the present invention can be suitably used for processing semiconductor members.

Claims

1. A semiconductor processing sheet comprising a substrate and a pressure-sensitive adhesive layer laminated on one side of the substrate, the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, The pressure-sensitive adhesive has a gel fraction of 85% or more and 97% or less after ultraviolet irradiation, The ratio of the surface resistivity of the pressure-sensitive adhesive layer before ultraviolet irradiation to the surface resistivity of the pressure-sensitive adhesive layer after ultraviolet irradiation (surface resistivity before ultraviolet irradiation / surface resistivity after ultraviolet irradiation) is 0.5 or more. A semiconductor processing sheet characterized by:

2. The surface resistivity of the pressure-sensitive adhesive layer before ultraviolet irradiation is 1.0 × 10 ８ Ω / □ or more, 1.0×10 １３ 2. The semiconductor processing sheet according to claim 1, characterized in that it has a resistivity of Ω / □ or less.

3. The surface resistivity of the pressure-sensitive adhesive layer before ultraviolet irradiation is 1.0 × 10 ８ Ω / □ or more, 1.0×10 １２ 3. The semiconductor processing sheet according to claim 1, wherein the resistivity is Ω / □ or less.

4. The surface resistivity of the pressure-sensitive adhesive layer after ultraviolet irradiation is 1.0 × 10 ８ Ω / □ or more, 2.0×10 １３ A semiconductor processing sheet according to any one of claims 1 to 3, characterized in that it has a resistivity of Ω / □ or less.

5. The surface resistivity of the pressure-sensitive adhesive layer after ultraviolet irradiation is 1.0 × 10 ８ Ω / □ or more, 1.0×10 １２ The semiconductor processing sheet according to any one of claims 1 to 4, characterized in that it has a resistance of Ω / □ or less.

6. The semiconductor processing sheet is a lamination step of laminating a plurality of semiconductor chips on a surface of the adhesive layer opposite to the base material; An expanding step of stretching the semiconductor processing sheet on which the semiconductor chips are stacked to separate the semiconductor chips from each other; a pick-up step of picking up the semiconductor chips individually while the semiconductor chips are spaced apart from each other; The semiconductor processing sheet according to any one of claims 1 to 5, which is used in a semiconductor processing method comprising:

7. The semiconductor processing sheet described in claim 6, characterized in that the stacking of the semiconductor chips in the stacking process is carried out by transferring multiple semiconductor chips obtained by dicing a semiconductor wafer or semiconductor package on a dicing sheet from the dicing sheet to the semiconductor processing sheet.

8. A lamination step of laminating a plurality of semiconductor chips on the adhesive layer side of the semiconductor processing sheet according to any one of claims 1 to 7; An expanding step of stretching the semiconductor processing sheet on which the semiconductor chips are stacked to separate the semiconductor chips from each other; a pick-up step of picking up the semiconductor chips individually while the semiconductor chips are spaced apart from each other; 1. A method for manufacturing a semiconductor device, comprising:

9. Use of the semiconductor processing sheet according to any one of claims 1 to 7 for a semiconductor processing method, The semiconductor processing method includes: a lamination step of laminating a plurality of semiconductor chips on a surface of the adhesive layer opposite to the base material; an expanding step of stretching the semiconductor processing sheet on which the semiconductor chips are stacked to separate the semiconductor chips from each other; a pick-up step of picking up the semiconductor chips individually while the semiconductor chips are spaced apart from each other; The use characterized by comprising:

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