Composition for temporary fixing, adhesive for temporary fixing, and method for producing thin wafer

Abstract

A composition for temporary fixation, which contains (A) a polymerizable component that contains a (meth) acrylic acid ester that contains an aromatic ring bonded to a heteroatom; (B) a photoradical polymerization initiator; and (C) an ultraviolet absorber having a polymerizable functional group. The equivalent weight of aromatic rings bonded to heteroatoms contained in 1 g of the temporary fixing composition is 0.50 mmol to 3 mmol.

Description

Technical Field

[0001] The present invention relates to a temporary fixing composition, a temporary fixing adhesive, and a method for producing a thin wafer. Background Art

[0002] When manufacturing electronic devices, wafer-type substrates with a thickness of about several hundred μm are often used. These are obtained by using an inorganic material represented by silicon as a substrate and performing processes such as insulating film formation, circuit formation, and thinning by grinding on the surface. However, most substrates are made of brittle materials and easily break, so measures are required to prevent damage, especially when thinning by grinding. Regarding this measure, a method has been adopted so far of attaching a temporary fixing protective tape that can be peeled off after the processing step is completed to the surface opposite to the grinding object surface (also called the back side). This tape uses an organic resin film as a base material and has flexibility, but lacks strength and heat resistance and is not suitable for use in high-temperature processes.

[0003] Therefore, a system has been proposed that achieves sufficient durability for the conditions of backside grinding and backside electrode formation by bonding electronic device substrates to a support member such as silicon or glass via an adhesive. The adhesive layer used to bond the substrate to the support member is crucial. This adhesive layer must ensure a seamless bond between the substrate and the support member, provide sufficient durability to withstand subsequent steps, and ultimately allow for easy removal of the thinned wafer from the support member, effectively securing it for temporary fixation.

[0004] The main steps in processing such a wafer include spin coating, vacuum bonding and photocuring, thinning by grinding and polishing, high-temperature treatment, laser lift-off, and temporary bonding agent removal.

[0005] In order to uniformly form a film of the temporary fixing agent on the wafer during the spin coating process, the temporary fixing agent is required to have a suitable viscosity and be a Newtonian fluid (or have shear rate independence of shear viscosity).

[0006] In the vacuum bonding / UV curing process, the temporary adhesive is required to be cured in a short time by irradiation with ultraviolet (UV) light or the like on a supporting member such as glass, and to generate little outgassing (low outgassing properties).

[0007] To prevent damage caused by localized load from the grinder applied to the substrate during thinning processes such as grinding and polishing, the temporary adhesive must have moderate hardness to distribute the load in-plane and prevent localized substrate sagging, thereby maintaining flatness. Furthermore, it must exhibit good adhesion to the support member, a moderately high elastic modulus to protect the edges, and chemical resistance.

[0008] In the high-temperature treatment process, the temporary bonding agent needs to have heat resistance that can withstand high-temperature treatment in a vacuum for a long period of time (for example, at a temperature of 300° C. or higher for more than one hour).

[0009] In the laser lift-off process, the temporary bonding agent needs to be able to be removed at high speed by a laser such as a UV laser.

[0010] In the removal process, in addition to easy peelability that allows the substrate to be easily peeled off from the support member, cohesive properties and easy cleaning properties are also required to prevent adhesive residue from remaining on the substrate after peeling.

[0011] In view of this background, for example, Patent Document 1 discloses a temporary fixing composition comprising: (A-1) a monofunctional (meth)acrylate whose side chain is an alkyl group having 18 or more carbon atoms and whose homopolymer has a Tg of -100°C to 60°C; (A-2) a polyfunctional (meth)acrylate; (B) a polyisobutylene homopolymer and / or a polyisobutylene copolymer; and (C) a photoradical polymerization initiator. The temporary fixing composition is claimed to have excellent heat resistance, low outgassing properties, and releasability.

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: International Publication No. 2021 / 235406 Summary of the Invention

[0015] When peeling off a cured temporary adhesive (i.e., adhesive layer) on a wafer, laser light is scanned through a transparent support member such as glass, decomposing the adhesive layer at the irradiated location. This creates a hole (a recessed portion covered by the support member). The gas vaporized within the hole expands due to the high temperature, pushing the support member upward and facilitating peeling.

[0016] However, since the radiation energy of the laser is absorbed, the irradiated area generates heat and the temperature rises. Therefore, the higher the laser irradiation power, the easier it is to decompose the cured temporary fixing agent. However, this also increases the temperature of the substrate adjacent to the temporary fixing agent, which is not preferred from the perspective of ensuring the quality of the substrate.

[0017] The present invention has been made in view of the above-mentioned problems. In one embodiment, the present invention aims to provide a temporary fixing composition that exhibits excellent releasability even under low-power laser irradiation. In another embodiment, the present invention aims to provide a temporary fixing adhesive comprising such a temporary fixing composition and a method for manufacturing a thin wafer using the temporary fixing adhesive.

[0018] The present inventors, through intensive research, have discovered that controlling the equivalent weight of heteroatom-bonded aromatic rings in a temporary fixing composition can solve the aforementioned problems. The reason for this, explained in detail below, is presumably that aromatic rings bonded to heteroatoms readily absorb laser light of a specific wavelength, allowing the adhesive layer to be decomposed even at low energies. The present invention, which was completed based on this knowledge, is exemplified below. [1]

[0020] A temporary fixing composition comprising the following (A) to (C),

[0021] (A) a polymerizable component comprising a (meth)acrylate containing an aromatic ring bonded to a heteroatom,

[0022] (B) a photoradical polymerization initiator,

[0023] (C) an ultraviolet absorber having a polymerizable functional group;

[0024] The equivalent weight of the aromatic ring bonded to the heteroatom contained in 1 g of the temporary fixing composition is 0.50 mmol to 3 mmol. [2]

[0026] The temporary fixing composition according to [1], wherein the component (A) comprises a 9,9-bis[4-(2-hydroxy C1-C 20 Alkoxy)phenyl]fluorene di(meth)acrylate, C1~C 20 Alkoxylated bisphenol A di(meth)acrylate, 1,3-bis(2-(meth)acryloyloxy C1-C 20 alkyl)benzene, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, or one or more structural isomers thereof. [3]

[0028] The temporary fixing composition according to [1], wherein the component (A) comprises one or more selected from nonylphenoxy polyethylene glycol (meth)acrylate, phenoxyethyl (meth)acrylate, and structural isomers thereof. [4]

[0030] The temporary fixing composition according to any one of [1] to [3], wherein the component (B) is one or more selected from bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyl oxime). [5]

[0032] The temporary fixing composition according to any one of [1] to [4], wherein the component (C) has one or more selected from a benzophenone skeleton, a triazole skeleton, a hydroxyphenyltriazine skeleton, and a phenol skeleton, and has a polymerizable functional group. [6]

[0034] The temporary fixing composition according to any one of [1] to [5], comprising 0.01 to 5 parts by mass of the component (B) and 0.005 to 15 parts by mass of the component (C) per 100 parts by mass of the total of the component (A). [7]

[0036] A temporary fixing adhesive comprising the temporary fixing composition according to any one of [1] to [6]. [8]

[0038] A method for manufacturing a thin wafer using the temporary fixing adhesive described in [7], comprising the following steps:

[0039] The thin wafer substrate is bonded to an optically transparent support member via the temporary fixing adhesive.

[0040] photocuring the temporary fixing adhesive from the support member side to form an adhesive layer, thereby bonding the substrate and the support member;

[0041] Processing the substrate to form a thin wafer; and

[0042] Light having a wavelength of 350 nm to 385 nm is irradiated from the support member side to decompose the adhesive layer, thereby peeling the thin wafer from the support member. [9]

[0044] A composition comprising the following (A) to (C),

[0045] (A) a polymerizable component comprising a (meth)acrylate containing an aromatic ring bonded to a heteroatom,

[0046] (B) a polymerization initiator,

[0047] (C) an ultraviolet absorber having a polymerizable functional group;

[0048] The equivalent weight of the aromatic ring bonded to the heteroatom contained in 1 g of the composition is 0.50 mmol to 3 mmol.

[0049] According to one embodiment of the present invention, a temporary fixing composition having excellent releasability even under low-power laser irradiation can be provided. In another embodiment, the present invention can provide a temporary fixing adhesive comprising such a temporary fixing composition, and a method for manufacturing a thin wafer using the temporary fixing adhesive. DETAILED DESCRIPTION

[0050] The present invention is not limited to the following embodiments, and it should be understood that appropriate design changes and improvements can be made based on the common knowledge of those skilled in the art without departing from the scope of the present invention.

[0051] In this specification, unless otherwise specified, the numerical range includes its upper limit and lower limit. In this specification, (meth)acrylate refers to a compound having one or more (meth)acryloyl groups in one molecule. Monofunctional (meth)acrylate refers to a compound having one (meth)acryloyl group in one molecule. Multifunctional (meth)acrylate refers to a compound having two or more (meth)acryloyl groups in one molecule. N-functional (meth)acrylate refers to a compound having n (meth)acryloyl groups in one molecule. As a polymerizable functional group in the multifunctional (meth)acrylate, it may have only an acryloyl group, only a methacryloyl group, or both an acryloyl group and a methacryloyl group. In addition, "C1 to C 20 ”, “C 10 ~C 20 " refers to a hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group having 10 to 20 carbon atoms.

[0052] In one embodiment of the present invention, there is provided a temporary fixing composition comprising the following (A) to (C).

[0053] (A) a polymerizable component comprising a (meth)acrylate containing an aromatic ring bonded to a heteroatom,

[0054] (B) a photoradical polymerization initiator,

[0055] (C) an ultraviolet absorber having a polymerizable functional group;

[0056] The equivalent weight of the aromatic ring bonded to the heteroatom contained in 1 g of the temporary fixing composition is 0.5 mmol to 3.0 mmol.

[0057] (1. (A) ingredient)

[0058] The polymerizable component (A) contained in the temporary fixing composition of this embodiment functions to form a (meth)acrylic acid polymer backbone. The temporary fixing composition of this embodiment may also contain a non-polymerizable component, preferably less than 15 parts by mass per 100 parts by mass of the non-polymerizable component and component (A). In this specification, "non-polymerizable component" is defined as a component other than component (B), i.e., a component not used as a photoradical polymerization initiator in this technical field.

[0059] The polymerizable component as component (A) contained in the temporary fixing composition of this embodiment contains a (meth)acryloyl group and plays a role in forming a (meth)acrylic acid polymer skeleton. As the polymerizable component, a polymerizable organic compound component is preferred. Component (A) preferably contains a compound having two or more (meth)acryloyl groups. Component (A) may be a monofunctional (meth)acrylate, a bifunctional (meth)acrylate, or a trifunctional or higher polyfunctional (meth)acrylate, or a mixture thereof. In addition, component (A) may preferably contain a combination of a polyfunctional (meth)acrylate and a monofunctional (meth)acrylate (more preferably a combination of a bifunctional (meth)acrylate and a monofunctional (meth)acrylate).

[0060] As polyfunctional (meth)acrylates that may be included in component (A), from the perspective of providing a rigid structure, aromatic bifunctional (meth)acrylates, alicyclic bifunctional (meth)acrylates, or mixtures thereof may be mentioned. Component (A) may also include a non-cyclic polyfunctional (meth)acrylate. The polyfunctional (meth)acrylate may be a monomer, a polymer, or a mixture thereof. In other words, the polymerizable polymer may be a polymer of a polyfunctional (meth)acrylate.

[0061] The molecular weight of the polyfunctional (meth)acrylate monomer is preferably 900 or less, more preferably 700 or less, further more preferably 500 or less, and further more preferably 400 or less.

[0062] The weight average molecular weight of the multifunctional (meth) acrylate polymer is preferably 5000 to 200000. By having a weight average molecular weight of 5000 or more for the multifunctional (meth) acrylate polymer, when combined with other polymerizable components, a moderate viscosity can be obtained. By having a weight average molecular weight of 10000 or more for the multifunctional (meth) acrylate polymer, a suitable thickening effect can be obtained. From this viewpoint, the weight average molecular weight of the multifunctional (meth) acrylate polymer is more preferably 6000 or more, and further more preferably 7000 or more. By having a weight average molecular weight of 200000 or less for the multifunctional (meth) acrylate polymer, good spin coating properties with low shear rate dependence can be obtained. From this viewpoint, the weight average molecular weight of the multifunctional (meth) acrylate polymer is more preferably 190000 or less, further more preferably 180000 or less, further more preferably 150000 or less, and particularly preferably 100000 or less.

[0063] The functional group equivalent of the multifunctional (meth)acrylate polymer is preferably 500 to 20,000, more preferably 700 to 10,000, and most preferably 1,000 to 7,000.

[0064] Examples of aromatic bifunctional (meth)acrylates include 9,9-bis[4-(2-hydroxy C1-C 20 Alkoxy)phenyl]fluorene di(meth)acrylate, C1~C 20 Alkoxylated bisphenol A di(meth)acrylate, benzyl di(meth)acrylate, 1,3-bis(2-(meth)acryloyloxy) C1-C 20 alkyl)benzene, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, or structural isomers thereof. Preferably, a di(meth)acrylate having a fused ring skeleton, such as a skeleton of fluorene, indene, indenocene, anthracene, azulene, or triphenylene may be included.

[0065] Examples of alicyclic bifunctional (meth)acrylates include C1 to C 20 Alkoxylated hydrogenated bisphenol A di(meth)acrylate, 1,3-di(meth)acryloyloxyadamantane, tricyclic C 10 ~C 20 Alkanedimethanol di(meth)acrylate, bicyclic C5~C 20 di(meth)acrylates, or structural isomers thereof, and the like.

[0066] Examples of the acyclic bifunctional (meth)acrylate include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, stearic acid-modified pentaerythritol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and caprolactone-modified hydroxypivalic acid neopentyl glycol di(meth)acrylate.

[0067] Component (A) may contain a trifunctional or higher polyfunctional (meth)acrylate. Examples of the trifunctional (meth)acrylate include isocyanuric acid ethylene oxide-modified tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tris[(meth)acryloyloxyethyl]isocyanurate.

[0068] Examples of tetrafunctional or higher-functional (meth)acrylates include ditrimethylolpropane tetra(meth)acrylate, dimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol ethoxytetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0069] The monofunctional (meth)acrylate that may be contained in the component (A) is preferably a monofunctional (meth)acrylate having a molecular weight of 550 or less, and more preferably a monofunctional alkyl (meth)acrylate having an alkyl group.

[0070] As the alkyl group, it is preferably selected from one or more of a linear alkyl group, a branched alkyl group, and an alicyclic alkyl group, and more preferably selected from one or more of a linear alkyl group and a branched alkyl group. From the perspective of improving compatibility with other components, component (A) preferably has a long-chain, branched, or cyclic alkyl group, for example, preferably a branched alkyl group such as isostearyl, isotetracosyl (2-decyl-1-tetradecyl, etc.), isotriacontyl (2-tetradecyl-1-octadecyl, etc.), or a cycloalkyl group having 18 to 40 carbon atoms, more preferably 18 to 32 carbon atoms. By using such a long-chain, high-molecular-weight component with strong aliphatic hydrocarbon properties (more preferably, improving the properties of the aliphatic hydrocarbon of the entire system), the low volatility, chemical resistance, and heat resistance required for the temporary fixing composition can be improved.

[0071] Component (A) is preferably at least one selected from the group consisting of stearyl (meth)acrylate, isostearyl (meth)acrylate, behenyl (meth)acrylate, 2-decyl-1-tetradecyl (meth)acrylate, 2-dodecyl-1-hexadecyl (meth)acrylate, and 2-tetradecyl-1-octadecyl (meth)acrylate. Component (A) is preferably a (meth)acrylate represented by the following formula 1.

[0072] Formula 1

[0073]

[0074] Where R 1 is a hydrogen atom or a methyl group, more preferably a hydrogen atom. 2 It is an alkyl group, and the number of carbon atoms thereof is preferably 18 to 32. One or more of these (meth)acrylates may be used.

[0075] As R 2 The monofunctional alkyl (meth)acrylate having an alkyl group having 18 to 32 carbon atoms is preferably a (meth)acrylate having a linear or branched alkyl group such as stearyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, behenyl (meth)acrylate, 2-decyl-1-tetradecyl (meth)acrylate, and 2-tetradecyl-1-octadecyl (meth)acrylate.

[0076] In the temporary fixing composition of the present embodiment, the component (A) contains a (meth)acrylate containing an aromatic ring bonded to a heteroatom.

[0077] The (meth)acrylate containing an aromatic ring bonded to a heteroatom may be a monofunctional (meth)acrylate, a bifunctional (meth)acrylate, or a trifunctional or higher polyfunctional (meth)acrylate, or a mixture thereof. Furthermore, component (A) may preferably contain a combination of a polyfunctional (meth)acrylate and a monofunctional (meth)acrylate, a combination of a polyfunctional (meth)acrylate and a polymerizable polymer, or a combination of a polyfunctional (meth)acrylate, a monofunctional (meth)acrylate, and a polymerizable polymer.

[0078] The number of aromatic rings in a (meth)acrylate containing an aromatic ring bonded to a heteroatom is not particularly limited and may be 1, 2, 3, 4, or more, or may be a mixture of (meth)acrylates having these numbers of aromatic rings. Furthermore, a (meth)acrylate containing an aromatic ring bonded to a heteroatom may also contain an aromatic ring that is not bonded to a heteroatom.

[0079] As described later, the (meth)acrylate containing an aromatic ring bonded to a heteroatom constitutes a part or all of the equivalents of the aromatic ring bonded to a heteroatom contained in 1 g of the temporary fixing composition of the present invention.

[0080] Examples of the (meth)acrylate containing an aromatic ring bonded to a heteroatom include bifunctional (meth)acrylates. Examples of bifunctional (meth)acrylates include 9,9-bis[4-(2-hydroxy C1-C 20 Alkoxy)phenyl]fluorene di(meth)acrylate, C1~C 20 Alkoxylated bisphenol A di(meth)acrylate, 1,3-bis(2-(meth)acryloyloxy C1-C 20 The present invention also includes one or more of the following: alkyl)benzene, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane (including ethoxylated bisphenol A di(meth)acrylate), or structural isomers thereof. Preferably, the present invention also includes a di(meth)acrylate having a fused ring skeleton, such as a fluorene, indene, indenocene, anthracene, azulene, or triphenylene skeleton.

[0081] Examples of (meth)acrylates containing an aromatic ring bonded to a heteroatom include, among other monofunctional (meth)acrylates, at least one selected from nonylphenoxy polyethylene glycol (meth)acrylate (including nonylphenol EO-modified (meth)acrylate), phenoxyethyl (meth)acrylate, and structural isomers thereof. Preferred (meth)acrylates include those having a fused ring skeleton, such as a fluorene, indene, indenocene, anthracene, azulene, or triphenylene skeleton.

[0082] In a preferred embodiment, the total amount of the (meth) acrylate containing an aromatic ring bonded to a heteroatom in component (A) relative to the mass of the entire component (A) can be in the range of 5 to 100 mass %. Specifically, the total amount of the (meth) acrylate containing an aromatic ring bonded to a heteroatom in component (A) relative to the mass of the entire component (A) is preferably 5 mass % or more, 10 mass % or more, 15 mass % or more, 20 mass % or more, 25 mass % or more, 30 mass % or more, 40 mass % or more, 50 mass % or more, or 60 mass % or more. In addition, the total amount of the (meth) acrylate containing an aromatic ring bonded to a heteroatom in component (A) is preferably 100 mass % or less, 90 mass % or less, 85 mass % or less, 80 mass % or less, 75 mass % or less, or 70 mass % or less.

[0083] The content of the component (A) is preferably 60 to 100% by mass, 70 to 98% by mass, 80 to 96% by mass, or 85 to 94% by mass relative to the total amount of the temporary fixing composition.

[0084] In a preferred embodiment, the amount of non-polymerizable components contained in the temporary fixing composition of this embodiment may be 0% by mass or more and less than 10% by mass, or 0% by mass or more and less than 5% by mass. The amount of non-polymerizable components may also be 10% by mass or less, or 5% by mass or less. More preferably, the temporary fixing composition of this embodiment may not contain any non-polymerizable components other than component (B).

[0085] (2. (B) Component)

[0086] The polymerization initiator, preferably a photoradical polymerization initiator, as component (B) contained in the temporary fixing composition of this embodiment is a substance that can initiate polymerization of component (A) upon exposure to light. For example, a photoradical polymerization initiator refers to a compound whose molecules are cleaved and split into two or more free radicals upon exposure to ultraviolet light or visible light (e.g., wavelengths of 350 to 700 nm, preferably 365 to 500 nm, and more preferably 385 to 450 nm). Examples of the photoradical polymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-O-benzoyl oxime, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyl oxime). The component (B) may contain one or more of these or a combination of two or more.

[0087] In a preferred embodiment of the present invention, the component (B) contained in the temporary fixing composition may contain an acylphosphine oxide compound. Preferred acylphosphine oxide compounds include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. As a photoradical polymerization initiator, it is preferred that it has high sensitivity and photobleaching properties, and has excellent deep curing ability. In addition, it is preferred that the absorption wavelength region for generating free radicals is expanded to a relatively long wavelength region. The absorption wavelength region of the above-mentioned preferred compound is a wavelength range of up to about 440nm, which is significantly different from the absorption wavelength region of the UV absorber used in the UV laser stripping process described later. In other words, the degree of UV curing hindrance caused by the UV absorber is small, and free radical polymerization can be initiated with light of a longer wavelength. Therefore, even in the coexistence of a UV absorber, the effect of being able to initiate free radical polymerization and thus curing at a relatively fast speed and efficiently can be obtained.

[0088] In a preferred embodiment, the photoradical polymerization initiator can be selected based on absorbance. Specifically, the photoradical polymerization initiator can be selected from one or more compounds that meet any one or more of the following conditions: when dissolved at a concentration of 0.1% by mass in a solvent that does not have a maximum absorption in the wavelength region of 300 to 500 nm (e.g., acetonitrile, toluene, etc.), the absorbance at a wavelength of 365 nm is 0.5 or more, the absorbance at a wavelength of 385 nm is 0.5 or more, and the absorbance at a wavelength of 405 nm is 0.5 or more. Examples of compounds satisfying such conditions include 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyl oxime), which has an absorbance of 0.5 or more at a wavelength of 365 nm when dissolved in acetonitrile as a solvent at a concentration of 0.1% by mass; 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-O-benzoyl oxime, which has an absorbance of 0.5 or more at wavelengths of 365 nm and 385 nm; and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide, which have absorbances of 0.5 or more at wavelengths of 365 nm, 385 nm, and 405 nm.

[0089] In addition, from the perspective of taking into account both the curing properties brought by the photoradical polymerization initiator and UV laser stripping, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium having an absorption wavelength region in the range of 400 to 500 nm can also be used as a photoradical polymerization initiator.

[0090] As the photoradical polymerization initiator (B), from the perspectives of reaction speed, heat resistance after curing, low outgassing properties, and absorption characteristics in a region different from both the wavelength of the UV laser used in UV laser stripping described below and the absorption wavelength region of the UV absorber used in the UV laser stripping process, at least one compound selected from the group consisting of acylphosphine oxide compounds, titanocene compounds, and α-aminoalkylphenylketone compounds is preferred. Furthermore, in addition to the above, oxime ester compounds can be selected as photoradical polymerization initiators for resin compositions used for temporary fixing purposes in the temporary fixing composition having the structure described below, rather than for use in the layer prepared for the UV laser stripping process. The temporary fixing purpose mentioned above refers to preventing damage during the process from bonding the substrate to the support member to the heating step.

[0091] Examples of the acylphosphine oxide-based compounds include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Among them, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is particularly preferred.

[0092] Examples of the titanocene-based compound include bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium.

[0093] Examples of the α-aminoalkylphenyl ketone compounds include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one and 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one.

[0094] Examples of oxime ester compounds include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-O-benzoyl oxime and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyl oxime). Among them, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyl oxime) is preferred.

[0095] In a preferred embodiment of the present invention, component (B) in the temporary fixing composition is one or more selected from bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyl oxime).

[0096] From the perspectives of reaction speed, heat resistance after curing, and low outgassing properties, the amount of the photoradical polymerization initiator (B) used is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, even more preferably 0.1 to 2 parts by mass, and even more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the total component (A). If the amount of component (B) is 0.01 parts by mass or more, sufficient curing properties can be obtained, while if it is 5 parts by mass or less, low outgassing properties and heat resistance can be effectively prevented from being impaired.

[0097] (3. (C) Component)

[0098] The ultraviolet absorber (UV absorber) having a polymerizable functional group as component (C) contained in the temporary fixing composition of this embodiment refers to the following compound: due to the irradiation of ultraviolet rays or visible light laser, the molecules are cut and decomposed and vaporized. This decomposition and vaporization occurs at the interface between the support member and the cured product of the temporary fixing composition (hereinafter also referred to as the temporary fixing agent), thereby causing the adhesion between the cured product of the temporary fixing composition and the support member that has been maintained until the UV laser stripping process to be lost. The (C) component is a compound having one or more selected from a benzophenone skeleton, a triazole skeleton, a hydroxyphenyltriazine skeleton and a phenol skeleton (preferably a hindered phenol skeleton). The purpose of having these skeletons is to obtain the degree of overlap between the UV absorption wavelength region and the UV laser wavelength, UV absorption characteristics at this wavelength, low outgassing, and heat resistance. The polymerizable functional group possessed by the (C) component is preferably a (meth)acryloyl group. In order to obtain the effect of the present invention well, the (C) component preferably has an absorption peak for light with a wavelength of 350nm to 385nm.

[0099] Examples of the component (C) include, from the viewpoints of compatibility with the resin component, UV absorption properties, low outgassing properties, and heat resistance, particularly preferably one or more selected from the group consisting of 2-[2-hydroxy-5-[2-((meth)acryloyloxy)ethyl]phenyl]-2H-benzotriazole, 2-[1-(2-hydroxy-3,5-di-tert-amylphenyl)ethyl]-4,6-di-tert-amylphenyl (meth)acrylate, 2-(2-(meth)acryloyloxy-5-methyl)phenyl-2H-benzotriazole, 1,1-bis-[2-(meth)acryloyloxy-3-(2H-benzotriazol-2-yl)-5-tert-octyl]methane, and 2,2′-dihydroxy-4,4′-di(meth)acryloyloxybenzophenone.

[0100] The amount of component (C) per 100 parts by mass of component (A) is preferably 0.005 to 15 parts by mass, more preferably 0.01 to 12 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.5 to 7 parts by mass. When the amount is 0.01 parts by mass or greater, a sufficient UV laser lift-off rate can be achieved, while when the amount is 15 parts by mass or less, low outgassing properties and a less deteriorating heat resistance can be achieved.

[0101] (4. Temporary Fixing Composition)

[0102] The equivalent weight of the aromatic ring bonded to the heteroatom contained in 1 g of the temporary fixing composition of the present invention is 0.50 mmol to 3 mmol.

[0103] Typically, the absorption peak of an aromatic ring is around 200 nm. However, when the element adjacent to the aromatic ring is a heteroelement such as P, S, or O, the conjugation length is extended, with the absorption edge extending to 355 nm. This is presumably due to increased absorption of laser energy and decomposition. However, the present invention is not bound by any theory.

[0104] From the above viewpoints, in order to enhance absorption of laser energy, the equivalent weight of heteroatom-bonded aromatic rings contained in 1 g of the temporary fixing composition is 0.50 mmol or more. The equivalent weight of heteroatom-bonded aromatic rings contained in 1 g of the temporary fixing composition is preferably 0.55 mmol or more, more preferably 0.6 mmol or more, even more preferably 0.60 mmol or more, further more preferably 0.65 mmol or more, further more preferably 0.7 mmol or more, and further more preferably 0.70 mmol or more.

[0105] However, if the equivalent weight of the aromatic rings bonded to heteroatoms is too high, it is possible that during heat treatment, the support member and the wafer will not be able to follow the deformation caused by the difference in linear expansion coefficient between the wafer and the support member, resulting in damage. From this viewpoint, the equivalent weight of the aromatic rings bonded to heteroatoms contained in 1g of the temporary fixing composition is 3 mmol or less. The equivalent weight of the aromatic rings bonded to heteroatoms contained in 1g of the temporary fixing composition is preferably 3.0 mmol or less, preferably 2.8 mmol or less, more preferably 2.5 mmol or less, further preferably 2 mmol or less, further preferably 2.0 mmol or less, further more preferably 1.9 mmol or less, further more preferably 1.8 mmol or less, further more preferably 1.7 mmol or less, and further more preferably 1.6 mmol or less.

[0106] In addition, the equivalent weight of the aromatic ring bonded to the heteroatom does not necessarily have to be derived from the component (A) and may be derived from the component (B) or the component (C).

[0107] If the equivalent weight of heteroatom-bonded aromatic rings per gram of the temporary fixing composition is 0.50 to 3 mmol, the adhesive layer can be decomposed even at low laser power, enabling peeling while suppressing heat generation. Furthermore, since the decomposition of the adhesive layer is accelerated, cleaning of the remaining adhesive layer after peeling can be expected to be easier.

[0108] (5. Adhesive for temporary fixation)

[0109] The temporary fixing composition of the present invention can be used as a temporary fixing adhesive, particularly as a temporary fixing adhesive for manufacturing electronic devices such as thin wafers. The temporary fixing adhesive is preferably composed solely of the temporary fixing composition of the present invention.

[0110] (6. Method for Manufacturing Thin Wafer)

[0111] Another embodiment of the present invention provides a method for manufacturing a thin wafer using the temporary fixing adhesive of the present invention. The method comprises the following steps: laminating a substrate of the thin wafer to an optically transparent support member via the temporary fixing adhesive; photocuring the temporary fixing adhesive from the support member to form an adhesive layer, thereby bonding the substrate and the support member; processing the substrate to form a thin wafer; and irradiating the support member with light having a wavelength of 350 nm to 385 nm to decompose the adhesive layer, thereby peeling the thin wafer from the support member.

[0112] The method of bonding the thin wafer substrate to the optically transparent support member is not particularly limited. Typically, a temporary fixing adhesive is applied to the optically transparent support member, and then the substrate is bonded to the surface coated with the temporary fixing adhesive.

[0113] As a coating method for the temporary fixing adhesive, known coating methods such as spin coating, screen printing, and various coating machines can be used. The viscosity of the temporary fixing composition of the present embodiment is preferably 500 mPa·s or more, more preferably 1000 mPa·s or more at 23°C (at atmospheric pressure), from the perspective of coating and operability. The viscosity of the temporary fixing composition of the present embodiment is preferably 15000 mPa·s or less, more preferably 10000 mPa·s or less, and even more preferably 5000 mPa·s or less at 23°C (at atmospheric pressure), from the perspective of coating and operability. If it is 500 mPa·s or more, the coating property, especially the coating property by spin coating, is excellent. If it is 15000 mPa·s or less, the operability is excellent. The viscosity can be measured using a known viscometer.

[0114] Spin coating is a method of applying the composition to the surface of a support member by dripping a liquid composition onto the support member and rotating the support member at a predetermined rotation speed. Spin coating can efficiently produce high-quality coating films.

[0115] When the substrate to be processed and the supporting member are bonded together, light is irradiated to cure the substrate. The wavelength of the light can be appropriately selected according to the type of the photo-radical polymerization initiator (B), and is typically 350 nm to 700 nm. It is particularly preferred to use visible light or ultraviolet light (wavelength or center wavelength 365 to 405 nm) with an energy of 1 to 20,000 mJ / cm 2 If the energy is 1mJ / cm 2 If the above, sufficient adhesion can be obtained, if it is 20000mJ / cm 2From the viewpoints of productivity, adhesion, low outgassing, and easy peeling, the preferred range is 1000 to 10000 mJ / cm 2 It should be noted that the wavelength of the light here is preferably selected from a range different from the wavelength of the laser light used for decomposing the adhesive layer described later.

[0116] The processing object substrate and the supporting member are not particularly limited, but preferably at least one substrate is a light-transmitting transparent substrate. Examples of the transparent substrate include inorganic substrates such as crystal, glass, quartz, calcium fluoride, magnesium fluoride, and organic substrates such as plastics. Among them, inorganic substrates are preferred from the viewpoint of having versatility and being able to obtain a significant effect. Among the inorganic substrates, one or more selected from glass and quartz are preferred.

[0117] After bonding the substrate to be processed and the support member, the substrate is processed to form a thin wafer. Typical processing includes thinning by grinding, polishing, and high-temperature treatment.

[0118] After thinning the wafer, light with a wavelength of 350 to 385 nm is irradiated from the support member side to degrade the adhesive layer. For example, the adhesive layer can be degraded by irradiating the entire surface with UV laser light with a wavelength of 350 to 385 nm in a scanning pattern. As mentioned above, aromatic rings bonded to heteroatoms readily absorb laser energy with a wavelength near 355 nm. Therefore, the effect of enhancing energy absorption is more pronounced by setting the laser wavelength within the 350 to 385 nm range.

[0119] Example

[0120] Hereinafter, the present invention will be described in further detail based on Examples and Comparative Examples, but the present invention is not limited thereto.

[0121] Unless otherwise specified, the experiments were conducted at 23° C. and 50% humidity. Temporary fixing compositions having the compositions shown in the following table (unit: parts by mass) were prepared and evaluated. The following compounds were selected as the components.

[0122] (composition)

[0123] As (A) component, the following components were used.

[0124] APB-001 (multifunctional acrylate polymer, manufactured by Negami Industries, Ltd., "APB-001", weight average molecular weight 72,000, functional group equivalent weight 1,400)

[0125] A-BPEF-2: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene diacrylate ("NK ESTER A-BPEF-2" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0126] ABE-300: Ethoxylated bisphenol A diacrylate ("NK ESTER ABE-300" manufactured by Shin-Nakamura Chemical Industry Co., Ltd., where R = -CH2CH2O-, m + n ≈ 3)

[0127] A-BPE-2: Ethoxylated bisphenol A diacrylate ("NK ESTER A-BPE-2" manufactured by Shin-Nakamura Chemical Industry Co., Ltd., wherein R = -CH2CH2O-, m = n = 1)

[0128]

[0129] HBPE-4: EO-modified hydrogenated bisphenol A diacrylate ("HBPE-4" manufactured by Daiichi Kogyo Seiyaku Co., Ltd., m+n≈4)

[0130] A-DOD-N: 1,10-decanediol diacrylate ("A-DOD-N" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0131] HX-220: Caprolactone-modified hydroxypivalate neopentyl glycol diacrylate ("Kayarad HX-220" manufactured by Nippon Kayaku Co., Ltd., m+n≈2)

[0132] HX-620: Caprolactone-modified hydroxypivalate neopentyl glycol diacrylate ("Kayarad HX-620" manufactured by Nippon Kayaku Co., Ltd., m+n≈4)

[0133] A-TMPT: Trimethylolpropane triacrylate ("A-TMPT" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0134] RC110C (a polymer with acrylate esters at both ends, "XMAP RC110C" manufactured by Kaneka Corporation, weight average molecular weight 12,000, functional group equivalent weight 6,000)

[0135] M-113: Nonylphenol EO-modified acrylate (Toagosei Co., Ltd., "Aronix M-113," n≈4)

[0136] ISTA: Isostearyl acrylate ("ISTA" manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0137] As the component (B), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide ("Irgacure 819" manufactured by BASF) was used.

[0138] As (C)component, the following components were used.

[0139] RUVA-93: 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole ("RUVA-93" manufactured by Otsuka Chemical Co., Ltd.)

[0140] P-66: 2,2'-dihydroxy-4,4'-diacryloyloxybenzophenone ("DAINSORB P-66" manufactured by Yamato Chemical Industry Co., Ltd.)

[0141] (Liquid sample preparation)

[0142] As shown in Tables 1-1 and 1-2, for each Comparative Example and Example, the temporary fixing composition was obtained by mixing the materials under heating at 60°C to form a uniform liquid composition. Furthermore, Tables 1-1 and 1-2 indicate the presence or absence of heteroatom-bonded aromatic rings for each component, and the equivalent weight of heteroatom-bonded aromatic rings calculated from the amounts of each component in each example is shown in parentheses. The calculation formula is as follows.

[0143] Equivalent weight of aromatic rings bonded to heteroatoms (mmol) = (number of components of the compound / molecular weight of the compound (g / mol)) × (number of aromatic rings bonded to heteroatoms contained in one molecule of the compound) × 1000

[0144] (Joint sample production)

[0145] A 4-inch silicon wafer (10 cm in diameter x 0.47 mm in thickness) and a 4-inch glass support member (10 cm in diameter x 0.7 mm in thickness) were bonded to the prepared liquid composition. During bonding, the thickness of the liquid composition was adjusted to 50 μm. After bonding, a black light with a wavelength of 365 nm was used at an illumination of 100 mW / cm 2 , irradiation time 50 seconds, cumulative light intensity 5000mJ / cm 2 The adhesive was cured under the conditions of , and placed on a hot plate heated to 180°C for 30 minutes to prepare a test piece for adhesive evaluation. The liquid composition was applied to the entire surface of the bonding surface.

[0146] (Evaluation of laser peelability)

[0147] A UV laser with a wavelength of 355 nm was irradiated from the glass support side of the obtained 4-inch test piece to scan the entire surface of the test piece onto a fixed circle with a diameter of 110 mm centered on the test piece.

[0148] Place the blade against the circumference of the test piece after laser irradiation to remove the protrusions beyond the circumference. For this test piece, place it on a multi-hole chuck type adsorption table with the silicon wafer facing down and fix it. Then, attach three suction cups with a diameter of 30 mm to the glass support member of the test piece from above. Install a load measurement module on the suction cups, pull it vertically upward, and measure the load required for peeling the glass support member using the above method. As a parameter for evaluating peelability, the laser power (W) required to achieve glass peeling before reaching a load of 10 N is measured and shown in Tables 1-1 and 1-2. The smaller the value, the easier it is to peel.

[0149]

[0150] The unit of the amount used is part by mass.

[0151]

[0152] The unit of the amount used is part by mass.

[0153] × indicates that the temporary fixative was broken.

[0154] The results in Tables 1-1 and 1-2 show that the temporary fixing composition of the present invention requires low laser power for peeling and has high peelability, thereby enabling peeling while suppressing heat generation.

[0155] On the other hand, in Comparative Example 1, where the equivalent weight of the aromatic ring bonded to the heteroatom was below the lower limit of the present invention, the laser power required for peeling was high, resulting in poor peelability. In Comparative Example 2, the temporary bonding agent cracked during the heat treatment of the test piece, making evaluation impossible.

Claims

1. A temporary fixing composition comprising the following (A) to (C), (A) a polymerizable component comprising a (meth)acrylate containing an aromatic ring bonded to a heteroatom, (B) a photoradical polymerization initiator, (C) an ultraviolet absorber having a polymerizable functional group; The equivalent weight of the aromatic ring bonded to the heteroatom contained in 1 g of the temporary fixing composition is 0.50 mmol to 3 mmol.

2. The temporary fixing composition according to claim 1, wherein The component (A) comprises a 9,9-bis[4-(2-hydroxy C1-C 20 Alkoxy)phenyl]fluorene di(meth)acrylate, C1~C 20 Alkoxylated bisphenol A di(meth)acrylate, 1,3-bis(2-(meth)acryloyloxy C1-C 20 alkyl)benzene, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, or one or more structural isomers thereof.

3. The temporary fixing composition according to claim 1, wherein The component (A) contains one or more selected from nonylphenoxy polyethylene glycol (meth)acrylate, phenoxyethyl (meth)acrylate, and structural isomers thereof.

4. The temporary fixing composition according to claim 1 or 2, wherein The component (B) is one or more selected from bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyl oxime).

5. The temporary fixing composition according to claim 1 or 2, wherein The component (C) has one or more skeletons selected from the group consisting of a benzophenone skeleton, a triazole skeleton, a hydroxyphenyltriazine skeleton, and a phenol skeleton, and has a polymerizable functional group.

6. The temporary fixing composition according to claim 1 or 2, wherein The component (B) is contained in an amount of 0.01 to 5 parts by mass, and the component (C) is contained in an amount of 0.005 to 15 parts by mass, relative to 100 parts by mass of the total of the component (A). 7 . A temporary fixing adhesive comprising the temporary fixing composition according to claim 1 .

8. A method for manufacturing a thin wafer using the temporary fixing adhesive according to claim 7, the method comprising the following steps: a step of bonding the thin wafer substrate to an optically transparent support member via the temporary fixing adhesive; a step of photocuring the temporary fixing adhesive from the support member side to form an adhesive layer and bonding the substrate and the support member; a step of processing the substrate to form a thin wafer; as well as and irradiating light having a wavelength of 350 nm to 385 nm from the support member side to decompose the adhesive layer and peel the thin wafer from the support member.

9. A composition comprising the following (A) to (C), (A) a polymerizable component comprising a (meth)acrylate containing an aromatic ring bonded to a heteroatom, (B) a polymerization initiator, (C) an ultraviolet absorber having a polymerizable functional group; The equivalent weight of the aromatic ring bonded to the heteroatom contained in 1 g of the composition is 0.50 mmol to 3 mmol.

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