Semiconductor processing sheet, method for manufacturing a semiconductor device, and use of the 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 formed from an adhesive composition that contains: an acrylic copolymer without active energy-ray curability; an active energy-ray curable component that comprises four or less functional groups with a double bond and whose weight average molecular weight is equal to or more than 5,000; and an alkylene glycol-based component that is at least one kind of alkylene glycol, polyalkylene glycol, and derivatives of those glycols.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a semiconductor processing sheet that can be suitably used in semiconductor processing, 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, 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 workpiece, such as a semiconductor wafer, is attached to a semiconductor processing sheet comprising a base material and an adhesive layer, and then processes such as backgrinding, dicing, cleaning, drying, expanding, picking up, and mounting are performed. Examples of such semiconductor processing sheets are disclosed in Patent Documents 1 and 2.

[0003] In the above-mentioned pickup process, to prevent the semiconductor chip to be picked from colliding with an adjacent semiconductor chip, the semiconductor processing sheet is generally stretched (expanded) to separate the semiconductor chips. If a collision occurs between semiconductor chips during pickup, it can not only lead to pickup failure but also damage to the semiconductor chip, so it is necessary to sufficiently suppress the occurrence of such collisions. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5027321 [Patent Document 2] Japanese Patent Publication No. 2014-120624 [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, the semiconductor processing sheet disclosed in Patent Document 1, mentioned above, has the objective of suppressing chip breakage during dicing. In other words, the semiconductor processing sheet disclosed in Patent Document 1 is intended for use in dicing. Furthermore, the semiconductor processing sheet disclosed in Patent Document 2 is a dicing sheet used for dicing.

[0006] In 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 the dicing process. When these semiconductor processing sheets are expanded after dicing, they can be expanded sufficiently because the adhesive layer is separated and cuts are made in the substrate.

[0007] On the other hand, when attempting to expand a semiconductor processing sheet without dicing, the adhesive layer and substrate remain integrated as they were initially, making it impossible to expand them sufficiently. This prevents the semiconductor chips from being sufficiently separated, resulting in pickup failures.

[0008] This invention has been made in view of the above circumstances, and aims to provide a semiconductor processing sheet that can sufficiently separate semiconductor chips from each other and enable good pickup of semiconductor chips, even when dicing is not performed. [Means for solving the problem]

[0009] To achieve the above objective, firstly, 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 formed from an adhesive composition containing an acrylic copolymer that does not have active energy ray curability, an active energy ray curable component having four or fewer functional groups having double bonds and a weight-average molecular weight of 5000 or more, and an alkylene glycol component which is at least one of alkylene glycol, polyalkylene glycol, and derivatives thereof (Invention 1).

[0010] The semiconductor processing sheet according to the above invention (Invention 1) allows for sufficient expansion and good pickup of semiconductor chips because the adhesive layer is formed from the above-described adhesive composition. In particular, because the adhesive composition contains the above-described acrylic copolymer and the above-described active energy ray curable component, the cured and uncured regions are appropriately distributed within the adhesive layer after active energy ray curing, thereby making the adhesive layer easier to expand. Furthermore, the above-described alkylene glycol component promotes a decrease in the adhesive strength of the adhesive layer to the semiconductor chip due to active energy ray curing, and also contributes to improving expandability. As a result, good pickup is possible with the above-described semiconductor processing sheet.

[0011] In the above invention (Invention 1), the active energy ray curable component is preferably an oligomer or modified product of a polyfunctional acrylate (Invention 2).

[0012] In the above inventions (Inventions 1 and 2), the weight-average molecular weight of the active energy ray-curable component is preferably 100,000 or less (Invention 3).

[0013] In the above inventions (Inventions 1 to 3), the semiconductor processing sheet is preferably used in a semiconductor processing method including a lamination step of laminating a plurality of semiconductor chips on a surface of the adhesive layer opposite to the base material, an expand step of stretching the semiconductor processing sheet on which the semiconductor chips are laminated to separate the semiconductor chips from each other, and a pickup step of individually picking up the semiconductor chips in a state where the semiconductor chips are separated from each other (Invention 4).

[0014] In the above invention (Invention 4), the lamination of the semiconductor chips in the lamination step is preferably performed by transferring a plurality of semiconductor chips obtained by dicing a semiconductor wafer or a semiconductor package on a dicing sheet to the semiconductor processing sheet from the dicing sheet (Invention 5).

[0015] Second, the present invention provides a method for manufacturing a semiconductor device, which includes a lamination step of laminating a plurality of semiconductor chips on a surface of the semiconductor processing sheet (Inventions 1 to 5) on the adhesive layer side, an expand step of stretching the semiconductor processing sheet on which the semiconductor chips are laminated to separate the semiconductor chips from each other, and a pickup step of individually picking up the semiconductor chips in a state where the semiconductor chips are separated from each other (Invention 6).

[0016] Third, the present invention provides a use for a semiconductor processing method of the semiconductor processing sheet (Inventions 1 to 5), the semiconductor processing method including a lamination step of laminating a plurality of semiconductor chips on a surface of the adhesive layer opposite to the base material, an expand step of stretching the semiconductor processing sheet on which the semiconductor chips are laminated to separate the semiconductor chips from each other, and a pickup step of individually picking up the semiconductor chips in a state where the semiconductor chips are separated from each other (Invention 7).

Advantages of the Invention

[0017] The semiconductor processing sheet according to the present invention can sufficiently separate semiconductor chips from each other even when dicing is not performed, enabling good pickup of the semiconductor chips.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described. The semiconductor processing sheet according to the present embodiment includes a base material and an adhesive layer laminated on one side of the base material.

[0019] 1. Components of the Semiconductor Processing Sheet (1) Base Material In the semiconductor processing sheet according to the present embodiment, the base material is not particularly limited as long as it exhibits a desired function when the semiconductor processing sheet is used. Since the adhesive layer in the present embodiment has active energy ray curability as described later, from the viewpoint of facilitating good reach of active energy rays to the adhesive layer, the base material preferably has good permeability to active energy rays.

[0020] In this embodiment, the substrate is preferably a resin film mainly composed of a resin-based material. Specific examples include polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate; ethylene-vinyl acetate copolymer films; ethylene copolymer films such as ethylene-(meth)acrylic acid copolymer films, ethylene-(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 film and vinyl chloride copolymer film; (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 materials can also be used. Furthermore, the substrate may be a laminated film formed by stacking multiple of the aforementioned films. In this laminated film, the materials constituting each layer may be of the same type or different types. In this specification, "(meth)acrylic acid" means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, the concept of "polymer" consisting of a single monomer is also included in the term "copolymer".

[0021] Furthermore, the substrate in this embodiment preferably comprises 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 for example, it is preferable to use a resin. As the resin, for example, it is preferable to use at least one of polyolefin resins and thermoplastic elastomers. The surface layer and the back layer may have different compositions or may have exactly the same composition.

[0022] In this specification, polyolefin resin refers to a homopolymer or copolymer with olefin as the monomer, or a copolymer with olefin and non-olefin molecules as monomers, wherein the mass ratio of the olefin unit-based portion in the polymerized resin is 1.0% by mass or more. Examples of such polyolefin resins include polyethylene and polypropylene. Examples of the above polypropylene include homopolypropylene, random polypropylene, and block polypropylene. Examples of the above polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, and linear low-density polyethylene. These may be used individually or in mixtures of two or more types.

[0023] The thermoplastic elastomer is not particularly limited as long as it is other than the polyolefin resins mentioned above and is capable of forming a substrate. Examples of thermoplastic elastomers include olefin elastomers, rubber elastomers, urethane elastomers, styrene elastomers, acrylic elastomers, vinyl chloride elastomers, and the like.

[0024] Examples of the above-mentioned olefin-based elastomers 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, and ethylene-propylene-butene-α-olefin copolymer. These may be used individually or in combination of two or more types.

[0025] Furthermore, examples of the above-mentioned styrene-based elastomers include styrene-conjugated diene copolymers and styrene-olefin copolymers, with styrene-conjugated diene copolymers being preferred. Examples of 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).

[0026] The base material may contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers. While there are no particular limitations on the content of these additives, it is preferable to keep it within a range that allows the base material to exhibit the desired function.

[0027] The surface of the substrate to which the adhesive layer 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.

[0028] The thickness of the substrate can be appropriately set depending on the method in which the semiconductor processing sheet is used, but is generally preferably 20 μm or more, and particularly preferably 25 μm or more. Furthermore, the thickness is generally preferably 450 μm or less, and particularly preferably 300 μm or less.

[0029] (2) Adhesive layer The adhesive layer in this embodiment is formed from an adhesive composition containing an acrylic copolymer that does not have active energy ray curability, an active energy ray curability component having four or fewer functional groups with double bonds and a weight-average molecular weight of 5000 or more, and an alkylene glycol component which is at least one of alkylene glycol, polyalkylene glycol, and their derivatives.

[0030] In this embodiment, the semiconductor processing sheet has an adhesive layer formed from the adhesive composition described above, which allows for sufficient expansion and enables good pickup of semiconductor chips. In particular, the semiconductor processing sheet in this embodiment can be sufficiently expanded even when semiconductor components are not diced on the sheet, thereby enabling good pickup.

[0031] Normally, when dicing is performed on a semiconductor processing sheet, the adhesive layer is cut along with the semiconductor component, and cuts are also made in the substrate. As a result, a diced semiconductor processing sheet becomes easier to stretch in the expansion process because the adhesive layer is finely divided and cuts are made in the substrate. In contrast, if dicing is not performed, this effect of ease of stretching does not occur. However, the semiconductor processing sheet according to this embodiment can be sufficiently expanded despite not obtaining this effect, thereby enabling good pick-up.

[0032] In particular, because the adhesive composition in this embodiment contains the above-mentioned acrylic copolymer and the above-mentioned active energy ray curable component, it expands more easily than when using an acrylic copolymer that itself has active energy ray curable groups. The reason for this is thought to be that, although not limited to this, when an adhesive layer containing two independent components, an acrylic copolymer and an active energy ray curable component, is cured by irradiation with active energy rays, cured and uncured regions occur at an appropriate frequency within the adhesive layer, allowing the adhesive layer to maintain a moderate degree of flexibility.

[0033] Furthermore, the adhesive composition in this embodiment can also achieve good expandability by containing the alkylene glycol-based component. Although the reason for this is not clear, it is possible that the hydroxyl groups of the alkylene glycol-based component moderately inhibit the reaction between the acrylic copolymer and the active energy ray-curable component upon irradiation with active energy rays, as well as the formation of crosslinks between the acrylic copolymers, resulting in the adhesive layer having appropriate flexibility.

[0034] Furthermore, the alkylene glycol-based component can also promote the reduction in adhesive strength to semiconductor chips 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 exhibit less reduction in adhesive strength during curing compared to active energy ray-curable adhesives composed of a single component, an acrylic copolymer having an active energy ray-curable group. However, the alkylene glycol-based component contained in the adhesive composition of this embodiment effectively promotes the aforementioned reduction in adhesive strength. Therefore, the semiconductor processing sheet according to this embodiment, combined with the effect of being sufficiently expandable as described above, enables good pick-up.

[0035] Furthermore, the weight-average molecular weight (Mw) used herein, including the weight-average molecular weight of the active energy ray-curable component mentioned above, is a value calculated on a standard polystyrene basis by gel permeation chromatography (GPC).

[0036] (2-1) Acrylic copolymer The acrylic copolymer in this embodiment is not particularly limited, as long as it does not possess active energy ray curability.

[0037] The acrylic copolymer is not particularly limited as long as it contains an acrylic monomer as a monomer unit constituting the polymer, but it is particularly preferable that it is copolymerized with at least an alkyl (meth)acrylate monomer. The alkyl (meth)acrylate monomer preferably has one or more carbon atoms in the alkyl group, and is particularly preferable to have two or more carbon atoms. Furthermore, the alkyl (meth)acrylate monomer preferably has 18 or fewer carbon atoms in the alkyl group, and is particularly preferable to have 8 or fewer carbon atoms.

[0038] Specific examples of the alkyl (meth)acrylate monomers mentioned above include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 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, from the viewpoint of making it easier to adjust the adhesive strength of the semiconductor processing sheet according to this embodiment to a desired range. The alkyl (meth)acrylate monomers mentioned above may be used alone or in combination of two or more.

[0039] The acrylic copolymer described above preferably contains 50% by mass or more of (meth)acrylate alkyl ester monomer as the monomer unit constituting the polymer, and more preferably 60% by mass or more. Furthermore, the acrylic copolymer preferably contains 98% by mass or less of (meth)acrylate alkyl ester monomer as the monomer unit constituting the polymer, and more preferably 95% by mass or less.

[0040] Furthermore, the acrylic copolymer described above is preferably composed of a functional group-containing monomer as the monomer unit constituting the polymer, from the viewpoint that the acrylic copolymer will be more easily crosslinked when the adhesive composition contains a crosslinking agent described later, and that the adhesive strength will be easier to adjust to a desired range. Examples of functional groups that the functional group-containing monomer may have include a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, an epoxy group, etc., with hydroxyl groups and carboxyl groups being preferred, and carboxyl groups being particularly preferred. Different types of functional group-containing monomers may be used in combination.

[0041] When using monomers containing a carboxyl group (carboxyl group-containing monomers) as functional group-containing monomers, examples include ethylenically unsaturated carboxylic acids, and specific examples include acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Among these, acrylic acid is preferred in terms of the reactivity of the carboxyl group and copolymerizability. These may be used individually or in combination of two or more.

[0042] When using monomers containing a hydroxyl group (hydroxyl group-containing monomers) as functional group-containing monomers, examples include hydroxyalkyl (meth)acrylates, and specific examples 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 from the viewpoint of the reactivity of the hydroxyl group and copolymerizability. These may be used alone or in combination of two or more.

[0043] The acrylic copolymer described above preferably contains 0.1% by mass or more of functional group-containing monomers as monomer units constituting the polymer, particularly preferably 0.5% by mass or more, and even more preferably 1% by mass or more. Furthermore, the acrylic copolymer preferably contains 30% by mass or less of functional group-containing monomers as monomer units constituting the polymer, particularly preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0044] The acrylic copolymer may contain other monomers besides the (meth)acrylate alkyl ester monomers and functional group-containing monomers mentioned above as monomer units constituting the polymer.

[0045] Examples of 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; aliphatic ring-containing (meth)acrylic acid esters such as cyclohexyl (meth)acrylate; aromatic ring-containing (meth)acrylic acid esters such as phenyl (meth)acrylate; non-crosslinked acrylamides such as acrylamide and methacrylamide; non-crosslinked tertiary amino group-containing (meth)acrylic acid esters such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate; vinyl acetate; and styrene. These may be used individually or in combination of two or more.

[0046] The polymerization mode of the acrylic copolymer may be random copolymer or block copolymer. Furthermore, the polymerization method is not particularly limited and can be polymerized by general polymerization methods.

[0047] In this embodiment, the weight-average molecular weight (Mw) of the acrylic copolymer 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 force of the 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 handling properties during adhesive layer formation.

[0048] (2-2) Active energy ray curable components The active energy ray curable component in this embodiment is not particularly limited, as long as it has four or fewer functional groups having double bonds and a weight-average molecular weight of 5000 or more. 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 will have good expandability.

[0049] Examples of the functional groups possessed by the active energy ray curable component include acryloyl groups and vinyl groups. From the viewpoint of facilitating expansion, the number of functional groups in the active energy ray curable component is preferably two or more and three or less.

[0050] Furthermore, the weight-average molecular weight of the active energy ray-curable component is preferably 7000 or more, and particularly preferably 8000 or more, from the viewpoint of making it easier to expand. Also, from the viewpoint of making it easier to achieve the 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 even more preferably 40,000 or less.

[0051] Preferred examples of the above-mentioned active energy ray curable component include polyfunctional acrylate oligomers or modified products. Preferred examples of the above-mentioned polyfunctional acrylate oligomers 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.

[0052] Examples of the above-mentioned modified materials include urethane-modified materials, epoxy-modified materials, and ester-modified materials. Among these, urethane-modified materials are preferred because they allow for easy adjustment of the weight-average molecular weight and the number of functional groups within the aforementioned ranges.

[0053] The above-mentioned urethane-modified product is preferably obtained by reacting the above-mentioned 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.

[0054] In this embodiment, the content of the active energy ray-curable component in the adhesive composition is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and more preferably 30 parts by mass or more, per 100 parts by mass of the acrylic copolymer described above. Furthermore, the content is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, and more preferably 150 parts by mass or less. When the content of the active energy ray-curable component is within the above range, the cured and uncured regions in the adhesive layer after irradiation with active energy rays are better distributed, making the semiconductor processing sheet easier to expand.

[0055] (2-3) Alkylene glycol-based components The alkylene glycol-based component in this embodiment is at least one of alkylene glycol, polyalkylene glycol, and their derivatives. By using this alkylene glycol-based component, the adhesive force of the semiconductor processing sheet to the adherend after irradiation with active energy rays can be effectively reduced, and the semiconductor processing sheet becomes easier to expand.

[0056] Examples of alkylene glycols include ethylene glycol, propylene glycol, butylene glycol, tetramethylene glycol, and glycerin.

[0057] Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, poly(ethylene-propylene) glycol, polybutylene glycol, and polytetramethylene polyglycerin. Among these, polyethylene glycol is preferred because it is easier to obtain the aforementioned effect of reducing tackiness and achieving good expansion.

[0058] The weight-average molecular weight of the polyalkylene glycol is preferably 30,000 or less, more preferably 20,000 or less, and even more preferably 10,000 or less. Having the weight-average molecular weight within this range makes it easier to sufficiently reduce the adhesive strength after irradiation with active energy rays, and also facilitates the expansion of the semiconductor processing sheet. The lower limit of the weight-average molecular weight may be, for example, 200 or less, more preferably 150 or less, or even 100 or less.

[0059] The above derivative is represented by the general formula X-(O-Ar)n-OY, where X and Y are, for example, a hydrogen atom, a modified rosin ester, a benzoic acid ester, stearic acid, etc., Ar is, for example, a hydrocarbon such as CH2 (methylene), C2H4 (ethylene), C3H6 (propylene), etc., and n is an integer from 1 to 200. A preferred example of the derivative is the use of an alkylene glycol-modified rosin ester.

[0060] While there are no particular limitations on the alkylene glycol-modified rosin esters mentioned above, it is preferable that they be obtained by esterifying rosins, polyalkylene glycol monoalkyl ethers, polyhydric alcohols, and α,β-unsaturated carboxylic acids, for example.

[0061] The weight-average molecular weight of the alkylene glycol-modified rosin ester is preferably 1000 or more, more preferably 2000 or more, and even more preferably 3000 or more. Furthermore, the weight-average molecular weight is preferably 1,000,000 or less, more preferably 100,000, more preferably 50,000 or less, and even more preferably 10,000 or less. Having the weight-average molecular weight within these ranges makes it easier to sufficiently reduce the adhesive strength after irradiation with active energy rays, and also makes it easier for the semiconductor processing sheet to expand well.

[0062] In this embodiment, the content of alkylene glycol-based components in the adhesive composition 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, per 100 parts by mass of the acrylic copolymer described above. 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. When the content of alkylene glycol-based components is within the above range, the adhesive strength is easily reduced sufficiently after irradiation with active energy rays, and the semiconductor processing sheet expands well.

[0063] (2-4) Crosslinking agents In this embodiment, the adhesive composition preferably contains a crosslinking agent. The inclusion of a crosslinking agent in the adhesive composition allows the acrylic copolymer to crosslink in the adhesive layer, forming a good three-dimensional network structure. This improves the cohesive strength of the resulting adhesive, effectively suppressing the generation of adhesive residue in the adherend separated from the semiconductor processing sheet after irradiation with active energy rays. When the adhesive composition contains a crosslinking agent, the acrylic copolymer preferably contains the above-mentioned functional group-containing monomers as monomer units constituting the polymer, and in particular, it is preferable to contain functional group-containing monomers having functional groups that are highly reactive with the crosslinking agent used.

[0064] Examples of the above crosslinking agents 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 according to the functional groups derived from the functional group-containing monomers present in the acrylic copolymer. These crosslinking agents can be used individually or in combination of two or more.

[0065] 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 their biuret and isocyanurate forms, as well as adducts which 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.

[0066] In this embodiment, when the adhesive composition contains a crosslinking agent, the amount of crosslinking agent in the adhesive composition is preferably 1 part by mass or more, and particularly preferably 5 parts by mass or more, per 100 parts by mass of the acrylic copolymer described above. Furthermore, the amount is preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less. A crosslinking agent content of 1 part by mass or more makes it easier to improve the cohesive force of the adhesive layer after irradiation with active energy rays, thereby effectively suppressing adhesive residue. Furthermore, a crosslinking agent content of 20 parts by mass or less results in an appropriate degree of crosslinking, making it easier for the adhesive layer to exhibit the desired adhesive strength.

[0067] (2-5) Photopolymerization initiator In this embodiment, the adhesive composition preferably contains a photopolymerization initiator. By containing a photopolymerization initiator in the adhesive composition, the polymerization curing time and the amount of light irradiation when curing the adhesive layer by irradiation with active energy rays can be reduced.

[0068] 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-chloranthraquinone, (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-diphenylethane-1-one. Among these, 1-hydroxycyclohexyl phenyl ketone is preferred. The photopolymerization initiators mentioned above may be used individually or in combination of two or more.

[0069] When the adhesive composition in this embodiment contains a photopolymerization initiator, the content of the photopolymerization initiator in the adhesive composition is preferably 0.1 parts by mass or more, and particularly preferably 1 part by mass or more, per 100 parts by mass of the acrylic copolymer described above. Furthermore, the content is preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less. By having the photopolymerization initiator content within the above range, the adhesive layer can be efficiently cured by irradiation with active energy rays, thereby making it easier to effectively reduce the adhesive strength of the semiconductor processing sheet to the adherend.

[0070] (2-6) Other ingredients The adhesive composition in this embodiment may contain desired additives, such as silane coupling agents, antistatic agents, tackifiers, antioxidants, light stabilizers, softeners, fillers, and refractive index modifiers, as long as they do not impair the aforementioned effects of the semiconductor processing sheet according to this embodiment. The polymerization solvent and diluent described later are not included in the additives constituting the adhesive composition.

[0071] (2-7) Method for preparing adhesive composition The adhesive composition in this embodiment can be produced by manufacturing an acrylic copolymer, and then mixing the obtained acrylic copolymer with an active energy ray curable component, an alkylene glycol component, and optionally a crosslinking agent, a photopolymerization initiator, and an additive.

[0072] Acrylic copolymers can be produced by polymerizing a mixture of monomers constituting the polymer using a conventional radical polymerization method. Preferably, this polymerization is carried out by solution polymerization, with the optional use of a polymerization initiator. Examples of polymerization solvents include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more solvents may be used in combination.

[0073] Examples of polymerization initiators include azo compounds and organic peroxides, and two or more may be used in combination. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane1-carbonitride), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane].

[0074] 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 peroxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, and diacetyl peroxide.

[0075] Furthermore, in the polymerization process described above, the weight-average molecular weight of the resulting polymer can be adjusted by incorporating a chain transfer agent such as 2-mercaptoethanol.

[0076] Once an acrylic copolymer is obtained, an adhesive coating solution can be obtained by adding an active energy ray curable component, an alkylene glycol component, and optionally a crosslinking agent, a photopolymerization initiator, other additives, and a diluent solvent to the acrylic copolymer solution and mixing thoroughly. If any of the above components are used in solid form, or if precipitation occurs when mixed with other components in an undiluted state, that component may be dissolved or diluted in a diluent solvent beforehand before mixing with the other components.

[0077] Examples of the diluent solvents used 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 solvents such as ethyl cellosolve.

[0078] The concentration and viscosity of the coating solution prepared in this manner are not particularly limited, as long as they are within the range of coating, and can be appropriately selected depending on the situation. For example, the adhesive composition is diluted to a concentration of 10% by mass or more and 60% by mass or less. Note that the addition of a diluent is not a necessary condition when obtaining the coating solution; if the adhesive composition has a viscosity suitable for coating, a diluent may not be added. In this case, the adhesive composition becomes a coating solution where the polymerization solvent of the acrylic copolymer is used directly as the diluent.

[0079] (2-8) Physical properties of the adhesive layer, etc. In the semiconductor processing sheet according to this embodiment, the gel fraction of the adhesive constituting the adhesive layer after irradiation with active energy rays is preferably 70% or more, particularly preferably 80% or more, and even more preferably 90% or more. Furthermore, the gel fraction is preferably 99% or less, particularly preferably 98% or less, and even more preferably 97% or less. When the gel fraction is within these ranges, the adhesive layer after irradiation with active energy rays contains an appropriate amount of uncured regions within it. As a result, even after irradiation with active energy rays, the adhesive layer is more likely to have the desired flexibility and be easily expanded. Details of the method for measuring the gel fraction are shown in the test examples described later.

[0080] 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. A thickness of 1 μm or more in the adhesive layer 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. A thickness of 20 μm or less in the adhesive layer makes it sufficiently expandable.

[0081] (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 structure of the release sheet is arbitrary, and an example is a plastic film that has 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. As the release agent, silicone-based, fluorine-based, and long-chain alkyl-based release agents can be used, and among these, silicone-based release agents are preferred because they are inexpensive and provide stable performance. There are no particular restrictions on the thickness of the release sheet, but it is usually 20 μm or more and 250 μm or less.

[0082] 2. Physical properties of semiconductor processing sheets (1) Adhesive strength In the semiconductor processing sheet according to this embodiment, the adhesive force to the silicon wafer (the mirror surface of a mirror-finished silicon wafer, hereinafter the same) before irradiation with active energy rays 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 according to this embodiment, since the adhesive layer is formed from an adhesive composition containing an active energy ray curable component, it is easier to achieve the above-mentioned adhesive force before irradiation with active energy rays. Furthermore, by having an adhesive force of 500 mN / 25 mm or more to the silicon wafer before irradiation with active energy rays, it becomes easier to fix the semiconductor chip well onto the semiconductor processing sheet and it becomes easier to prevent unintended detachment of the semiconductor chip. While there are no particular limitations on the upper limit of the adhesive strength, it is preferably 20,000 mN / 25 mm or less, more 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 described in the test examples below.

[0083] Furthermore, in the semiconductor processing sheet according to this embodiment, the adhesive force to the silicon wafer after irradiation with active energy rays is preferably 1500 mN / 25 mm or less, particularly 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, since the adhesive layer is formed from an adhesive composition containing an active energy ray curable component, it is easier to achieve the above-mentioned adhesive force after irradiation with active energy rays. And, by having an adhesive force to the silicon wafer of 1500 mN / 25 mm or less after irradiation with active energy rays, it becomes easier to peel the semiconductor chip from the semiconductor processing sheet and the generation of adhesive residue can be effectively suppressed. Furthermore, the adhesive force to the silicon wafer after irradiation with active energy rays is preferably 1 mN / 25 mm or more, particularly 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 and detachment of the semiconductor chip at a stage after irradiation with active energy rays. Further details regarding the method for measuring the adhesive strength are described in the test examples below.

[0084] (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 preferable that the ratio is Ω / □ or less, and especially 5.0 × 10 12 It is preferable that the ratio is Ω / □ or less, and more preferably 1.0 × 10⁻⁶. 12 It is preferable that the surface resistivity is Ω / □ or less. Having the surface resistivity within this range prevents the adherend from being damaged by peeling charge when the semiconductor processing sheet according to this embodiment is peeled from the adherend. The lower limit of the surface resistivity of the adhesive layer before UV irradiation is not particularly limited; for example, 1.0 × 10 8 It may be Ω / □ or greater. Details of the above surface resistivity measurement method are as described in the test examples below.

[0085] Furthermore, in the semiconductor processing sheet according to this embodiment, the surface resistivity of the adhesive layer after ultraviolet irradiation is 1.0 × 10 13 It is preferable that the ratio is Ω / □ or less, and especially 5.0 × 10 12 It is preferable that the ratio is Ω / □ or less, and more preferably 1.0 × 10⁻⁶. 12 It is preferable that the surface resistivity is Ω / □ or less. Having the surface resistivity within this range prevents the adherend from being damaged by peeling charge when the semiconductor processing sheet according to this embodiment is peeled off from the adherend. The lower limit of the surface resistivity of the adhesive layer after ultraviolet irradiation is not particularly limited; for example, 1.0 × 10 8 It may be Ω / □ or greater. Details of the above surface resistivity measurement method are as described in the test examples below.

[0086] Furthermore, in the semiconductor processing sheet according to this embodiment, 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 preferably 0.5 or more, particularly preferably 0.6 or more, and even more preferably 0.7 or more. Also, the above ratio is preferably 0.95 or less, particularly preferably 0.9 or less, and even more preferably 0.8 or less. When the above ratio is within these ranges, it is easier to achieve good expandability even after irradiation with active energy rays. The reasons for this are not limited to the following: When the surface resistivity before and after ultraviolet irradiation is within the above range, it can be said that the surface resistivity of the adhesive layer does not change significantly before and after curing by irradiation with active energy rays. Here, it has been empirically confirmed that surface resistivity is correlated with the flexibility of the adhesive layer, and when the above ratio is satisfied, it can be said that the flexibility of the adhesive layer does not change significantly before and after irradiation with active energy rays. As a result, even after the adhesive layer hardens due to active energy ray irradiation, a certain degree of flexibility is maintained, and good expandability is preserved.

[0087] 3. Method for manufacturing semiconductor processing sheets The method for manufacturing the semiconductor processing sheet according to this embodiment is not particularly limited, and is preferably manufactured by laminating an adhesive layer on one side of a substrate.

[0088] Lamination of an adhesive layer onto one side of a substrate can be carried out by known methods. For example, it is preferable to transfer an 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 peeled surface of the release sheet (hereinafter sometimes referred to as the "release surface") using a die coater, curtain coater, spray coater, slit coater, knife coater, applicator, etc. to form a coating film, and the adhesive layer can be formed by drying the coating film. 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. The release sheet in this laminate may be peeled off as a process material, or it may be used to protect the adhesive surface of the adhesive layer until the semiconductor processing sheet is attached to the adherend.

[0089] If the coating liquid for forming the adhesive layer contains a crosslinking agent, the crosslinking reaction between the acrylic copolymer and the crosslinking agent in the coating film can be advanced 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.

[0090] Instead of transferring the adhesive layer formed on the release sheet to one side of the substrate as described above, the adhesive layer may be formed directly on the substrate. In this case, the coating liquid for forming the adhesive layer is applied to one side of the substrate to form a coating film, and the adhesive layer is formed by drying the coating film.

[0091] 4. How to use semiconductor processing sheets The semiconductor processing sheet according to this embodiment can be used for processing semiconductor components and for manufacturing semiconductor devices. That is, after attaching the adhesive surface of the semiconductor processing sheet according to this embodiment 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.

[0092] As described above, the semiconductor processing sheet according to this embodiment can sufficiently separate semiconductor chips through the expansion process even when dicing is not performed (i.e., when the adhesive layer is not cut together with the semiconductor component), and as a result, good pickup of semiconductor chips becomes possible. Therefore, the semiconductor processing sheet according to this embodiment is preferably used in a semiconductor processing method or a semiconductor device manufacturing method that performs an expansion process and a pickup process without performing a dicing process on the semiconductor processing sheet.

[0093] More specifically, the semiconductor processing sheet according to this embodiment is preferably used in a semiconductor processing method or a semiconductor device manufacturing method comprising: a lamination step of laminating semiconductor chips on the side of the adhesive layer opposite to the substrate; an expansion step of stretching the semiconductor processing sheet on which the semiconductor chips are laminated to separate the semiconductor chips from each other; and a pickup step of individually picking up the semiconductor chips while they are separated from each other.

[0094] In the lamination process described above, the multiple semiconductor chips to be laminated on the semiconductor processing sheet according to this embodiment may be obtained in advance by dicing a semiconductor wafer or semiconductor package on a dicing sheet. The multiple semiconductor chips obtained in this way can be laminated 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 carried out in the same way as in the past. Furthermore, the expansion process and the pickup process can also be carried out using conventional methods.

[0095] Furthermore, the above semiconductor processing method and semiconductor processing method may also include an irradiation step in which an active energy ray is irradiated onto the adhesive layer. This irradiation step is preferably performed between the lamination step and the expansion step, or between the expansion step and the pickup step. In the irradiation step, the adhesive layer is irradiated with an active energy ray and hardened, thereby reducing the adhesive strength to the semiconductor chip. This makes it easier to separate the semiconductor chip from the adhesive layer in the pickup step, and facilitates good pickup. As the active energy ray, ultraviolet light, electron beams, etc. are usually used, and ultraviolet light, which is easy to handle, is particularly preferred. The irradiation conditions for the active energy ray can be the same as in the conventional method.

[0096] Furthermore, the semiconductor processing sheet according to this embodiment may be used not only for the semiconductor processing method described above, but also for backgrinding and dicing.

[0097] 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.

[0098] For example, other layers may be provided between the substrate and the adhesive layer, or on the surface of the substrate opposite to the adhesive layer. [Examples]

[0099] 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.

[0100] [Example 1] (1) Preparation of the base material 30 parts by mass of random polypropylene resin (manufactured by Nippon Polypropylene Co., Ltd., product name "Novatec FX3B"), 45 parts by mass of olefin-based thermoplastic elastomer (manufactured by Nippon Polypropylene Co., Ltd., product name "Wellnex RFX4V"), and 25 parts by mass of antistatic agent (manufactured by Sanyo Chemical Industries, Ltd., product name "Pelektron PVH", melt flow rate: 9.8 g / 10 min) were dried separately and then mixed in a twin-screw compounder to obtain pellets for the surface layer.

[0101] Furthermore, 28 parts by mass of random polypropylene resin (manufactured by Nippon Polypropylene Co., Ltd., product name "Novatec FX3B"), 39 parts by mass of olefin-based thermoplastic elastomer (manufactured by Nippon Polypropylene Co., Ltd., product name "Wellnex RFX4V"), and 33 parts by mass of styrene-based thermoplastic elastomer (manufactured by Asahi Kasei Corporation, product name "ToughTec H1041", styrene-ethylene / butylene-styrene copolymer, styrene ratio: 30 wt%) were dried separately and then mixed in a twin-screw kneader to obtain pellets for the intermediate layer.

[0102] Furthermore, 70 parts by mass of olefin-based thermoplastic elastomer (manufactured by Nippon Polypropylene Co., Ltd., product name "Wellnex RFX4V") and 30 parts by mass of antistatic agent (manufactured by Sanyo Chemical Industries, Ltd., product name "Pelektron PVH", melt flow rate: 9.8 g / 10 min) were dried separately and then mixed in a twin-screw compounder to obtain pellets for the back layer.

[0103] Using the three types of pellets obtained as described above, co-extrusion molding was performed using a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplastmill"), and the resulting material was fed into the hopper of a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., screw diameter: 50 mm, effective screw length L / D: 32). The extruder temperature was set to C1: 210°C, C2: 230°C, C3: 230°C, C4: 230°C, and C5: 230°C, and the material was 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 using a winding machine equipped with a cooling roll (cooling roll: 700 mm wide × φ350 mm, roll temperature: 30°C), obtaining a three-layer substrate with a 2 μm thick surface layer, a 64 μm thick intermediate layer, and a 14 μm thick back layer, all laminated in sequence.

[0104] (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 placed in a flask, and after purging with nitrogen, the mixture was heated at 280°C for 13 hours while stirring. Then, the xylene was removed under reduced pressure at 200°C for 20 minutes. Subsequently, the contents were removed from the flask and cooled to room temperature to solidify, thereby obtaining alkylene glycol-modified rosin ester as an alkylene glycol-based component.

[0105] (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 later and was found to be 600,000.

[0106] 100 parts by mass (on a solid content basis, the same applies hereafter) of the obtained (meth)acrylic acid ester copolymer, 48 parts by mass of urethane acrylate (manufactured by Daicel Ornex, 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 alkylene glycol-modified rosin ester as an alkylene glycol-based component prepared in step (2) above, 3 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF, product name "Omnirad 184") as a photopolymerization initiator, and 4.5 parts by mass of 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 solution of the adhesive composition (solid content concentration: 25% by mass).

[0107] (4) Formation of the adhesive layer A release sheet (Lintec Corporation, product name "SP-PET381031"), which has a silicone-based release agent layer formed on one side of a 38 μm thick polyethylene terephthalate (PET) film, was coated with the adhesive composition solution described above and dried by heating to form a 5 μm thick adhesive layer on the release sheet.

[0108] (5) Fabrication of semiconductor processing sheets By bonding the exposed surface of the adhesive layer formed in step (4) above with the surface layer side of the substrate prepared in step (1) above, a semiconductor processing sheet with a release liner was obtained.

[0109] (6) Measurement of the weight-average molecular weight (Mw) of (meth)acrylic acid ester copolymers The weight-average molecular weight (Mw) of the (meth)acrylic acid ester copolymer described above is the weight-average molecular weight on a polystyrene basis, measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement). <Measurement conditions> • GPC measuring device: Tosoh Corporation, HLC-8020 • GPC column (passes through in the following order): Manufactured by Tosoh Corporation TSK Guard Column HXL-H TSK gel GMHXL (x2) TSK gel G2000HXL • Measurement solvent: tetrahydrofuran ·Measurement temperature: 40℃

[0110] [Examples 2-15 and Comparative Examples 1-11] A semiconductor processing sheet was manufactured 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.

[0111] Further details regarding the abbreviations and other terms listed in Table 1 are as follows: [Activated energy ray-curing component] KRM8961: A urethane acrylate with 2-3 functional groups and a weight-average molecular weight of 10,000 (manufactured by Daicel Ornex, product name "KRM8961"). EBECRYL230: A urethane acrylate with 2 functional groups and a weight-average molecular weight of 5,000 (manufactured by Daicel Ornex, product name "EBECRYL230"). PN-3660: A urethane acrylate with 4 functional groups and a weight-average molecular weight of 7,000 (manufactured by 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 6 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 (manufactured by Sigma-Aldrich, product name "PEG3000", weight-average molecular weight: 2700-3300) PTMG3000: Polytetramethylene Ether Glycol (manufactured by Mitsubishi Chemical Corporation, product name "PTMG3000", weight average molecular weight: 2900)

[0112] [Test Example 1] (Measurement of Adhesive Strength) The semiconductor processing sheets produced in the examples and comparative examples were left standing in an environment of 23°C and 50% humidity for 1 week, and then cut into a size of 25 mm in width and 300 mm in length.

[0113] Then, the release sheet was peeled off, and the exposed surface of the adhesive layer was overlapped with the mirror surface of a 6-inch silicon wafer, and a load was applied by reciprocating a 2 kg roller once to bond them, and they were left for 20 minutes. This was used as a laminate for measuring adhesive strength.

[0114] Regarding the obtained laminate for measuring adhesive strength, according to the 180° peel method in accordance with JIS Z0237:2009, the semiconductor processing sheet was peeled off from the silicon wafer at a peel rate of 300 mm / min and a peel angle of 180°, and the adhesive strength (mN / 25 mm) was measured. This measured value was used as the adhesive strength before UV irradiation and is shown in Table 1.

[0115] Also, with respect to the surface on the base material side of the semiconductor processing tape in the laminate for measuring adhesive strength obtained in the same manner as above, using an ultraviolet irradiation device (manufactured by LINTEC Corporation, product name "RAD-2000"), ultraviolet (UV) irradiation (irradiance: 200 mW / cm 2 , light quantity: 180 mJ / cm 2 ) was performed under nitrogen to cure the adhesive layer. Then, the adhesive strength (mN / 25 mm) was measured in the same manner as above. This measured value was used as the adhesive strength after UV irradiation and is shown in Table 1.

[0116] [Test Example 2] (Measurement of Expansion Amount) The adhesive layer exposed by peeling the release sheet from the semiconductor processing sheet manufactured in Example 1 (hereinafter sometimes referred to as the "dicing sheet") was attached to the polished surface of a 6-inch silicon wafer (thickness: 350 μm, polished to #2000) using a tape mounter (Lintec Corporation, product name "RAD-2500m / 12"). Subsequently, the outer periphery of the exposed surface of the dicing sheet (the area where the 6-inch silicon wafer is not present) was fixed to a ring frame, and the 6-inch silicon wafer was diced under the following conditions. <Dicing conditions> • Dicing machine: DISCO Corporation, product name "DFD-6362" • Blade: DISCO Corporation, product name "NBC-ZH2050-27HECC" • Blade rotation speed: 30,000 rpm ·Cutting speed: 50mm / min • Cutting depth: Amount of cut relative to the substrate: 20 μm • Dicing size: 1mm x 1mm

[0117] After dicing is complete, the dicing sheet is irradiated with ultraviolet (UV) light from the substrate side using a UV irradiation device (Lintec Corporation, product name "RAD-2000") under nitrogen (illuminance: 200mW / cm²). 2 ,Light amount: 180mJ / cm 2 The adhesive layer was cured by performing the following procedure.

[0118] Subsequently, the chips obtained by the dicing process were transferred from the dicing sheet to the exposed adhesive layer of the semiconductor processing sheet manufactured in the examples and comparative examples, 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.

[0119] Then, under nitrogen conditions, ultraviolet (UV) irradiation (illuminance: 200 mW / cm²) is applied to the substrate side of the semiconductor processing sheet using an ultraviolet irradiation device (Lintec Corporation, product name "RAD-2000"). 2 ,Light amount: 180mJ / cm2 The adhesive layer was cured by performing the following procedure.

[0120] Next, a semiconductor processing sheet with stacked chips was placed in an expander (JCM Corporation, product name "ME-300B", semi-automatic expander). Then, five pairs of adjacent chips were selected from the chips stacked on the semiconductor processing sheet. These five pairs of chips consisted of one pair located in the center of the semiconductor processing sheet when viewed from above, and four pairs located at 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 taken as the chip spacing before expansion. Subsequently, the semiconductor processing sheet was expanded at a speed of 1 mm / sec and a pull-down amount of 10 mm. After expansion, the distance (μm) between the five pairs of chips selected as described above was measured again, and the average value was taken as the chip spacing after expansion.

[0121] As described above, the difference in tip spacing before expansion was calculated by subtracting the tip spacing after expansion from the tip spacing after expansion, and this was defined as the expansion amount (μm). The measurement results are shown in Table 1.

[0122] [Test Example 3] (Measurement of interlayer adhesion) The semiconductor processing sheets manufactured in the examples and comparative examples were subjected to ultraviolet (UV) irradiation (illuminance: 200 mW / cm²) from the substrate side using an ultraviolet irradiation device (Lintec Corporation, product name "RAD-2000") while the release sheet was still attached, under air conditions. 2 ,Light amount: 180mJ / cm 2 The adhesive layer was cured by performing the following procedure.

[0123] Subsequently, the release liner was removed from the semiconductor processing sheet, exposing the hardened adhesive layer. Cuts were then made in this adhesive layer at 5mm intervals, creating a grid pattern (100 squares). The depth of the cuts was adjusted to completely penetrate the adhesive layer (5μm) but not deeply into the substrate (80μm) (specifically, between 5μm and 50μm).

[0124] 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 standing for 20 minutes at 23°C and 50% RH (relative humidity), the semiconductor processing sheet was held down with one hand, and the end of the cellophane adhesive tape was held with the other hand and the cellophane adhesive tape was pulled perpendicular to the semiconductor processing sheet, causing it to peel off from the surface of the adhesive layer instantaneously.

[0125] After peeling off the cellophane adhesive tape, the grid-like cuts on the adhesive layer of the semiconductor processing sheet were visually inspected, and the number of squares where delamination between the adhesive layer and the substrate had occurred was counted. The results are shown in Table 1.

[0126] Furthermore, the number of peeled-off squares mentioned above serves as an indicator of the interlayer adhesion between the adhesive layer and the substrate in the semiconductor processing sheet after UV irradiation. In other words, the fewer the number of peeled-off squares, the better the interlayer adhesion between the adhesive layer and the substrate.

[0127] [Test Example 4] (Measurement of surface resistivity) The semiconductor processing sheets produced in the examples and comparative examples were cut to a size of 100 mm x 100 mm, and these were used as samples for surface resistivity measurement (before UV irradiation).

[0128] Furthermore, the semiconductor processing sheets, which have been similarly cut, are subjected to ultraviolet (UV) irradiation (illuminance: 200 mW / cm²) under air conditions using an ultraviolet irradiation device (Lintec Corporation, product name "RAD-2000") while the release sheet is still attached. 2 ,Light amount: 180mJ / cm 2The adhesive layer was cured by performing the following procedure, and this was used as a sample for surface resistivity measurement (after UV irradiation).

[0129] As described above, the two types of surface resistivity measurement samples were conditioned for 24 hours at 23°C and 50% relative humidity. After peeling off the release sheet, the surface resistivity (Ω / □) of the exposed adhesive layer was measured using a digital electrometer (ADVANTEST) with an applied voltage of 100V. The results are shown in Table 1.

[0130] [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 x 140 mm. After cutting, the release sheet was peeled off the semiconductor processing sheet, and diced chips (10 x 100 chips of 1 mm x 1 mm size) were transferred to the exposed adhesive layer using a laminator, in the same manner as in Test Example 2.

[0131] Next, the substrate side of the semiconductor processing sheet on which the chips are stacked is irradiated with ultraviolet (UV) light (illuminance: 200 mW / cm²) under nitrogen using an ultraviolet irradiation device (Lintec Corporation, product name "RAD-2000"). 2 ,Light amount: 180mJ / cm 2 The adhesive layer was cured by performing the following procedure.

[0132] Next, the semiconductor processing sheet with the attached chips, after the adhesive layer had hardened, was placed on a tensile testing machine (Orientec Co., Ltd., product name "Tensilon RTA-T-2M"). The distance (μm) between the two chips in the center of the semiconductor processing sheet was then measured and used as the chip spacing before the tensile test.

[0133] Subsequently, in accordance with JIS K7161:2014, a tensile test was performed using the above-mentioned tensile testing machine at a temperature of 23°C and relative humidity of 50%, with a chuck distance of 100 mm and a tensile speed of 200 mm / min. The tensile test was continued until the chuck distance became 110 mm, and this position was held for 4 minutes. Then, the distance (μm) between the two chips whose chip spacing was measured as described above was measured and defined as the chip spacing after the tensile test.

[0134] As described above, 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. Furthermore, the same measurement was performed on two different tips, and the average value of the difference in tip spacing obtained from these two tips was calculated and is shown in Table 1 as the tip spacing (μm) related to tensile measurement with tips.

[0135] The two sets of chips (a total of four chips) selected for the above measurements were chosen so that they were aligned in a straight line parallel to the extrusion direction (MD direction) during the molding of the semiconductor processing sheet substrate.

[0136] [Test Example 6] (Measurement of Gel Fraction) A laminate was obtained by forming a 5 μm thick adhesive layer on a release sheet (Lintec Corporation, product name "SP-PET381031") in the same manner as described in step (4) of [Example 1]. Furthermore, a sheet for measuring gel fraction was obtained by bonding the release surface of a release sheet (Lintec Corporation, product name "SP-PET382150") to the adhesive layer side of the laminate.

[0137] The obtained gel fraction measurement sheet was cut to a size of 80 mm x 80 mm, and one side of it was irradiated with ultraviolet (UV) light (illuminance: 200 mW / cm²) under air using an ultraviolet irradiation device (Lintec Corporation, product name "RAD-2000"). 2 ,Light amount: 180mJ / cm 2 The adhesive layer was cured by performing the following procedure.

[0138] Next, the hardened adhesive layer (adhesive) obtained by removing the release sheets from both sides was 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 as M1.

[0139] Next, the adhesive wrapped in the mesh described above was immersed in ethyl acetate solvent at room temperature (23°C) for 24 hours. After that, the mesh containing the adhesive was 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 dried adhesive alone was then weighed using a precision balance. This mass was designated as M2.

[0140] Then, the gel fraction (%) of the adhesive after UV irradiation was calculated by performing the calculation (M2 / M1) × 100. The results are shown in Table 1.

[0141] [Table 1]

[0142] As can be seen from Table 1, the semiconductor processing sheets obtained in the examples showed a greater expansion amount and a larger chip spacing value in the chipped tensile measurement compared to the comparative example. Therefore, it was found that the semiconductor processing sheets obtained in the examples can be expanded well even without dicing. [Industrial applicability]

[0143] The semiconductor processing sheet of the present invention can be suitably used for processing semiconductor components.

Claims

1. A semiconductor processing sheet comprising a base material and an adhesive layer laminated on one side of the base material, The adhesive layer, Acrylic copolymers that do not exhibit active energy ray curability, An active energy ray curable component having four or fewer functional groups with double bonds and a weight-average molecular weight of 5000 or more, An alkylene glycol-based component which is at least one of alkylene glycol derivatives and polyalkylene glycol derivatives. It is formed from an adhesive composition containing A semiconductor processing sheet characterized by the following features.

2. The semiconductor processing sheet according to claim 1, characterized in that the active energy ray curable component is an oligomer or modified product of a polyfunctional acrylate.

3. The semiconductor processing sheet according to claim 1 or 2, characterized in that the weight-average molecular weight of the active energy ray curable component is 100,000 or less.

4. The aforementioned semiconductor processing sheet is A lamination step of stacking a plurality of semiconductor chips on the side of the adhesive layer opposite to the substrate, An expansion step is performed to stretch the semiconductor processing sheet on which the semiconductor chips are stacked, thereby separating the semiconductor chips from each other. A pickup step in which the semiconductor chips are picked up individually while they are separated from each other. A semiconductor processing sheet according to any one of claims 1 to 3, characterized in that it is used in a semiconductor processing method comprising the same equipment.

5. The semiconductor processing sheet according to claim 4, characterized in that the stacking of semiconductor chips in the stacking process is performed by transferring a plurality of semiconductor chips obtained by dicing a semiconductor wafer or semiconductor package on a dicing sheet from the dicing sheet to the semiconductor processing sheet.

6. A lamination step of stacking a plurality of semiconductor chips on the adhesive layer side of a semiconductor processing sheet according to any one of claims 1 to 5, An expansion step is performed to stretch the semiconductor processing sheet on which the semiconductor chips are stacked, thereby separating the semiconductor chips from each other. A pickup step in which the semiconductor chips are picked up individually while they are separated from each other. A method for manufacturing a semiconductor device, characterized by comprising the above.

7. Use of a semiconductor processing sheet according to any one of claims 1 to 5 for a semiconductor processing method, The aforementioned semiconductor processing method is A lamination step of stacking a plurality of semiconductor chips on the side of the adhesive layer opposite to the substrate, An expansion step is performed to stretch the semiconductor processing sheet on which the semiconductor chips are stacked, thereby separating the semiconductor chips from each other. A pickup step in which the semiconductor chips are picked up individually while they are separated from each other. A use characterized by comprising the following features.

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