Composition for temporary fixation

Abstract

To reduce air bubbles mixing in a spin coat step in production of electronic devices.SOLUTION: A temporary fixation composition containing the following (A)-(C) and characterized by a viscosity in a range of 500-10000 mPa s under atmospheric pressure at 23°C. measured by a rotary rheometer and a shear rate of 1 s-1. (A) A monofunctional (meth) acrylate in which a surface tension measured by a ds / de method by a pendant drop method at 23°C. is in the range of 20-30 mN / m (B) A polyfunctional (meth)acrylate in which the viscosity at 23°C. measured by a rotary rheometer and having a shear rate of 1 s-1 is 1000 mPa s or more under atmospheric pressure, or is solid at 23°C., or a molecular weight is 500 or more and the viscosity of 23°C measured by a rotary rheometer at a shear rate of 1 s-1 is 100 mPa s or more and less than 1000 mPa s under atmospheric pressure (C) Photoradical polymerization initiator.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a composition for use in temporary fixation. [Background technology]

[0002] In the manufacture of electronic devices, inorganic materials such as silicon are often used as substrates, and wafer-type substrates with a thickness of about several hundred microns are often used, which are obtained by forming an insulating film on the surface, forming circuits, and thinning by grinding. However, since many substrates are made of brittle and easily cracked materials, measures to prevent damage are necessary, especially when thinning by grinding. A conventional method for this measure is to apply a temporary protective tape to the surface opposite to the surface to be ground (also called the back surface), which can be peeled off after the processing process is completed. This tape uses an organic resin film as the base material, and while it is flexible, it is insufficient in strength and heat resistance, making it unsuitable for use in high-temperature processes.

[0003] In response to this, a system has been proposed in which an electronic device substrate is bonded to a support such as silicon or glass via an adhesive, thereby providing sufficient durability to withstand the conditions of the back grinding and back electrode formation processes. In this case, the adhesive layer used to bond the substrate to the support is important. This must be able to bond the substrate to the support without any gaps, and must be durable enough to withstand subsequent processes. Finally, it must be possible to easily peel off the thinned wafer from the support, i.e., to temporarily fix it.

[0004] The processing of such wafers mainly involves a spin coating step, a vacuum bonding and light curing step, thinning by grinding and polishing, a high-temperature treatment step, a laser peeling step, and a temporary fixing agent removal step.

[0005] In the spin coating process, in order to form a uniform film of the temporary fixative on the wafer, it is required that the temporary fixative has an appropriate viscosity and is a Newtonian fluid (or has a shear viscosity that is independent of the shear rate).

[0006] In the vacuum bonding / UV curing process, the temporary fixative must be able to cure in a short time on a support such as glass by exposure to ultraviolet (UV) light, and must generate little outgassing (low outgassing properties).

[0007] In the thinning process by grinding and polishing, in order to avoid damage caused by the load of the grinding machine being applied locally to the substrate, the temporary fixative must have an appropriate hardness to distribute the load in the in-plane direction while preventing localized sinking of the substrate and maintaining flatness. In addition, adhesive strength with the support, an appropriate elastic modulus to protect the edges, and chemical resistance are also required.

[0008] In the high-temperature treatment process, the temporary fixing agent is required to have heat resistance capable of withstanding high-temperature treatment in a vacuum for a long period of time (for example, at 300° C. or higher for one hour or more).

[0009] In the laser peeling process, the temporary fixative is required to be able to be peeled off quickly by a laser such as a UV laser.

[0010] In the removal step, in addition to easy peelability so that the substrate can be easily peeled off from the support, the adhesive is required to have cohesive properties so that no adhesive residue remains on the substrate after peeling, and easy cleanability.

[0011] In view of this background, for example, Patent Document 1 discloses a temporary fixing composition containing (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 polyisobutene homopolymer and / or a polyisobutene copolymer, and (C) a photoradical polymerization initiator, and claims that the composition has excellent heat resistance, low outgassing properties, and peelability. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] International Publication No. 2021 / 235406 Summary of the Invention [Problem to be solved by the invention]

[0013] When a temporary fixing agent according to the related art is applied to a wafer by spin coating, it has been reported that air bubbles are generated in the temporary fixing agent and are trapped therein. Since air bubbles have a detrimental effect on physical properties, there has been a demand for reducing this phenomenon. [Means for solving the problem]

[0014] The present inventors have elucidated the mechanism of this air bubble inclusion and have come up with a means for eliminating it.

[0015] Aspect 1. The composition contains the following (A) to (C), and is measured by a rotational rheometer at 23°C and a shear rate of 1 s -1 2. A temporary fixing composition having a viscosity of 500 to 10,000 mPa·s under atmospheric pressure. (A) A monofunctional (meth)acrylate having a surface tension in the range of 20 to 30 mN / m as measured by the ds / de method using the pendant drop method at 23°C. (B) Measured by a rotational rheometer at 23°C and a shear rate of 1 s -1 The viscosity at atmospheric pressure is 1000 mPa·s or more, or the material is solid at 23°C, or the molecular weight is 500 or more and the viscosity at atmospheric pressure is 1000 mPa·s or more, or the material is solid at 23°C and the shear rate is 1 s -1 A polyfunctional (meth)acrylate having a viscosity of 100 mPa·s or more and less than 1000 mPa·s at atmospheric pressure. (C) Photoradical polymerization initiator

[0016] Aspect 2. In the mass ratio of the component (A) to the component (B), the amount of the component (A) is in the range of 5 to 65%. The temporary fixing composition according to embodiment 1.

[0017] Aspect 3. The temporary fixing composition according to aspect 1 or 2, wherein the component (A) is an aliphatic monofunctional (meth)acrylate.

[0018] Aspect 4. The temporary fixing composition according to aspect 3, wherein the aliphatic group of the component (A) has 6 or more and 30 or less carbon atoms.

[0019] Aspect 5. The temporary fixing composition according to any one of Aspects 1 to 4, wherein the component (B) includes an oligomer or a polymer.

[0020] Aspect 6. The temporary fixing composition according to any one of Aspects 1 to 5, further comprising the following (D): (D) UV absorber

[0021] Aspect 7. A cured product of the temporary fixing composition according to any one of aspects 1 to 6.

[0022] Aspect 8. 8. The cured product according to embodiment 7, which has a 2% mass loss temperature of 300° C. or higher under a nitrogen atmosphere.

[0023] Aspect 9. A method for producing a substrate for an electronic device, comprising the steps of: mixing a monofunctional (meth)acrylate, a polyfunctional (meth)acrylate, and a photoradical polymerization initiator to prepare a composition having a viscosity at 23°C in the range of 500 to 10,000 mPa s; A step of applying the prepared composition onto a silicon wafer by a spin coating method so that the surface of the applied composition is flat with a height difference of 40 μm or less; Adhering a support to the silicon wafer so as to sandwich the applied composition; A manufacturing method comprising:

[0024] Aspect 10. A temporary fixing adhesive comprising the temporary fixing composition according to any one of the first to sixth aspects.

[0025] Aspect 11. An adhesive structure comprising the temporary fixing adhesive according to aspect 10 and a substrate bonded by the temporary fixing adhesive.

[0026] Aspect 12. A method for producing a thin wafer using the temporary fixing adhesive according to aspect 10. Effect of the Invention

[0027] According to the present invention, a novel composition is provided that can reduce the inclusion of air bubbles during the spin coating process in the manufacture of electronic devices. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In this specification, unless otherwise specified, the numerical range includes the upper and lower limits. In this specification, a monofunctional (meth)acrylate refers to a compound having one (meth)acryloyl group in one molecule. A multifunctional (meth)acrylate refers to a compound having two or more (meth)acryloyl groups in one molecule. An n-functional (meth)acrylate refers to a compound having n (meth)acryloyl groups in one molecule. The polymerizable functional group in the multifunctional (meth)acrylate may have only an acryloyl group, may have only a methacryloyl group, or may have both an acryloyl group and a methacryloyl group.

[0029] In an embodiment of the present invention, it is possible to provide a temporary fixing composition (also referred to as a "temporary fixing agent") that contains (A) a monofunctional (meth)acrylate having predetermined physical properties, (B) a polyfunctional (meth)acrylate having predetermined physical properties, and (C) a photoradical polymerization initiator, and that has a predetermined viscosity overall. The present inventors discovered that in a coating process of a temporary fixing agent by spin coating in a manufacturing process of a substrate for an electronic device, the target substrate rotates, and the temporary fixing agent thereon is slightly deformed by centrifugal force, and the amount of this slight deformation affects the presence or absence of air bubbles being mixed in, and thus arrived at the present invention.

[0030] It is known that in the spin coating process, centrifugal force can cause a rise (called an "edge bead") near the edge of the target object, but in the field of acrylate-based temporary fixing agents consisting of a combination of monofunctional (meth)acrylate and polyfunctional (meth)acrylate, it was unknown what caused the edge bead to occur. That is, the edge bead will become high if several conditions are not met, namely the combination of the surface tension of the monofunctional (meth)acrylate and the viscosity of the polyfunctional (meth)acrylate, and the viscosity of the mixture, and if the height of the edge bead is 40 μm or less, air bubbles are unlikely to be trapped when the wafer and support are bonded together. This problem was solved by the present invention based on the discovery.

[0031] In this specification, the viscosity of the entire composition is measured at 23° C. (atmospheric pressure) using a rotational rheometer at a shear rate of 1 s -1 The viscosity at the time of spin coating is in the range of 500 to 10,000 mPa·s. The viscosity is preferably 500 to 8,000 mPa·s, and more preferably 500 to 5,000 mPa·s. If the viscosity of the entire composition is less than 500 mPa·s, the coating property is low and the composition is not suitable for practical use. If the viscosity of the entire composition is more than 10,000 mPa·s, the viscosity is too high and the composition is not suitable for spin coating. In this specification, the viscosity of the component (B) described later is also measured in the same manner as above.

[0032] The monofunctional (meth)acrylate, component (A) contained in this composition, is characterized by having a surface tension in the range of 20 to 30 mN / m, as measured by the ds / de method using the pendant drop method at 23°C. Although it is hypothetical, it is presumed that if the surface tension of component (A), which plays a role in forming a relatively flexible skeleton in the composition, falls within a narrow, specific range, it will be less susceptible to deformation due to centrifugal force due to interaction with component (B).

[0033] The ds / de method is a method in which the maximum diameter (equatorial diameter) de of a hanging drop formed by the pendant drop method and the diameter ds of the hanging drop at a position de above the lowest end of the hanging drop are measured, and the surface tension γ is calculated using the following formula. γ = ρg(de) 2 (1 / H) In the formula, ρ is density, g is gravitational acceleration, and 1 / H is a correction term calculated from ds / de. The ds / de method is known from, for example, the following literature. https: / / www.scas.co.jp / technical-informations / technical-news / pdf / tn142.pdf

[0034] The type of component (A) can be selected based on the ds / de method. When component (A) contains two or more types of monofunctional (meth)acrylates, the surface tension of the mixture can be measured to determine the surface tension. The surface tension of the entire composition can also be measured in the same manner as for component (A) alone, and may preferably be in the range of 28 to 33 mN / m at 23°C. Although it is hypothetical, it is believed that there is a direct proportional correlation between the surface tension of the composition and the height of the edge bead described below.

[0035] The component (A) is preferably an aliphatic monofunctional (meth)acrylate. The number of carbon atoms in the aliphatic group may be 6 to 30, and more preferably 8 to 20. It is hypothesized that the above-mentioned surface tension effect is easily obtained when the component (A) has a moderately strong hydrophobicity. In addition, it is generally considered that a monofunctional (meth)acrylate with a strong polarity such as acryloylmorpholine is not suitable because the surface tension is too high.

[0036] In terms of the mass ratio of the component (A) to the component (B), the amount of the component (A) is preferably in the range of 5 to 65%, more preferably 5 to 60%, and even more preferably 10 to 50%.

[0037] The polyfunctional (meth)acrylate, which is the component (B) contained in this composition, has a shear rate of 1 s at 23°C measured using a rotational rheometer. -1 The viscosity at atmospheric pressure is 1000 mPa s or more, or the material is solid at 23°C, or the molecular weight is 500 or more and the shear rate at 23°C measured by a rotational rheometer is 1 s-1 The viscosity at atmospheric pressure is 100 mPa·s or more and less than 1000 mPa·s (preferably 120 mPa·s or more and less than 1000 mPa·s). Note that in the above, "the viscosity at ... 23°C is 1000 mPa·s or more at atmospheric pressure, or it is solid at 23°C" is essentially the latter of the two descriptions that describes the upper limit of the viscosity (i.e., being solid can also be interpreted as having a very high viscosity). For this reason, please note that the absence of a specified upper limit when looking only at the above description "the viscosity at ... 23°C is 1000 mPa·s or more at atmospheric pressure" does not mean that it is technically unclear.

[0038] Without wishing to be bound by a particular theory, it is speculated that by combining the (B) component having such a viscosity or molecular weight or being a solid at room temperature with the above-mentioned (A) component, the alkyl groups of the (A) component face outward from the molecule and come to the surface, resulting in the effect of reducing edge beads. The type of the (B) component can be selected based on the method for measuring viscosity. When the (B) component contains two or more types of multifunctional (meth)acrylates, the viscosity can be determined by measuring the viscosity of the mixture.

[0039] The component (B) may be a monomer, or may contain an oligomer or polymer.

[0040] The photoradical polymerization initiator, which is the component (C) contained in the present composition, is a substance capable of initiating radical polymerization of the components (A) and (B) upon irradiation with light, and is, for example, a compound whose molecules are cleaved and split into two or more radicals upon irradiation with ultraviolet light or visible light (for example, wavelengths of 350 nm to 700 nm, preferably 365 nm to 500 nm, and more preferably 385 nm to 450 nm). Examples of photoradical polymerization initiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(η 5-2,4-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-benzoyloxime, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime). The component (C) may contain one or more of these or a combination of two or more of them.

[0041] Preferably, the component (C) may contain an acylphosphine oxide compound. Preferred acylphosphine oxide compounds include at least one of the group consisting of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. The photoradical polymerization initiator is preferably highly sensitive and has excellent deep curing properties due to its photofading properties, and the absorption wavelength range for generating radicals is preferably extended to a relatively long wavelength range. In the above-mentioned preferred compounds, the absorption wavelength range is in the range up to a wavelength of about 440 nm, which is significantly different from the absorption wavelength range of the UV absorber used in the UV laser peeling process described later. In other words, the degree of UV curing inhibition by the UV absorber is small, and radical polymerization can be initiated with light of a longer wavelength. Therefore, even in the presence of a UV absorber, the effect of initiating radical polymerization and curing efficiently at a relatively high speed can be obtained.

[0042] 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 satisfy one or more of the following conditions when dissolved at a concentration of 0.1 mass % in a solvent (e.g., acetonitrile, toluene, etc.) that does not have a maximum absorption in the wavelength region of 300 nm to 500 nm: absorbance of 0.5 or more at a wavelength of 365 nm, absorbance of 0.5 or more at a wavelength of 385 nm, and absorbance of 0.5 or more at a wavelength of 405 nm. Examples of compounds that satisfy such conditions include 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime), 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-benzoyloxime, 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 an absorbance of 0.5 or more at wavelengths of 365 nm, 385 nm, and 405 nm.

[0043] In addition, from the viewpoint of achieving both the curing property by the photoradical polymerization initiator and the UV laser peeling property, bis(η 5 -2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium can also be used as a photoradical polymerization initiator.

[0044] As the (C) photoradical polymerization initiator, one or more selected from acylphosphine oxide compounds, titanocene compounds, and α-aminoalkylphenone compounds are preferred in terms of reaction speed, heat resistance after curing, low outgassing, and absorption characteristics in a region different from the wavelength of the UV laser used in the UV laser peeling described later and the absorption wavelength region of the UV absorber used in the UV laser peeling. In addition to the above, oxime ester compounds can also be selected as photoradical polymerization initiators for resin compositions for temporary fixing applications for preventing damage from bonding of a substrate to be processed to a support substrate to a heating step, which is not a layer for responding to the UV laser peeling process, among the temporary fixing compositions having the structure described later.

[0045] Examples of the acylphosphine oxide compound include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc. Among these, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is particularly preferred.

[0046] Titanocene compounds include bis(η 5 -2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium.

[0047] Examples of the α-aminoalkylphenone compounds include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one, and the like.

[0048] Examples of oxime ester compounds include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-O-benzoyloxime, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime), etc. Among these, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime) is preferred.

[0049] The amount of the photoradical polymerization initiator (C) used is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 1 part by mass, per 100 parts by mass of the total of the components (A) and (B) in terms of reaction rate, heat resistance after curing, and low outgassing. When the amount of the component (C) is 0.01 part by mass or more, sufficient curability is obtained, and when it is 5 parts by mass or less, the effect of low outgassing and heat resistance being less likely to be impaired is obtained.

[0050] The present composition may contain a UV absorber as component (D). The UV absorber refers to a compound whose molecules are cut and decomposed / vaporized by irradiation with ultraviolet light or a visible light laser, and the decomposition / vaporization occurs at the interface between the support substrate (or support) and the temporary fixing agent, causing a loss of the adhesive force between the temporary fixing agent and the support substrate (or support) that had been maintained up until just before the peeling step.

[0051] As the (D) UV absorbent, one or more compounds selected from benzotriazole-based compounds, benzophenone-based compounds, and hydroxyphenyltriazine-based compounds are preferred in terms of the degree of overlap with the UV laser wavelength in the UV absorption wavelength region, UV absorption characteristics at the same wavelength, low outgassing properties, and heat resistance.

[0052] As the benzotriazole-based compound, one or more selected from the group consisting of 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2,2'-methylenebis[6-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol], 2-(2H-benzotriazole-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, and 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimido-methyl)-5-methylphenyl]benzotriazole and 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole are particularly preferred in terms of compatibility with the resin component, UV absorption characteristics, low outgassing properties, and heat resistance.

[0053] As the hydroxyphenyltriazine compound, one or more compounds selected from the group consisting of 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis-butyloxyphenyl)-1,3,5-triazine, and 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine are particularly preferred in terms of compatibility with components (A) and (B), UV absorption characteristics, low outgassing properties, and heat resistance.

[0054] As the benzophenone compound, one or more compounds selected from 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-diacryloyloxybenzophenone, and hydroxybenzophenone compounds are particularly preferred in terms of compatibility with components (A) and (B), UV absorption characteristics, low outgassing, and heat resistance.

[0055] In a preferred embodiment for the UV laser peeling step, the most preferred UV absorber is one or more selected from the group consisting of 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis-butyloxyphenyl)-1,3,5-triazine, or 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol]. These have excellent compatibility with component (A), high melting points, and relatively low vapor pressures under temperature conditions of about 300°C or less, so that the amount of use can be selected within a wide range, and can contribute to reducing outgassing from the cured temporary fixing composition under the temperature conditions.

[0056] As the UV absorber (D), it is most preferable to use an absorber selected based on the UV transmittance listed below. When component (D) has such a UV transmittance, it is possible to obtain the effect of appropriately controlling the curing and peeling of the composition.

[0057] When the UV absorbent is dissolved in a solvent that does not have a maximum absorption in the wavelength range of 290 to 410 nm at a concentration of 0.002% by mass, the transmittance at a wavelength of 355 nm and at a wavelength of 385 to 420 nm at an optical path length of 1 cm is preferably 50% or less, and more preferably 40% or less at a wavelength of 355 nm and 60% or more at a wavelength of 385 to 420 nm.

[0058] Examples of (D) UV absorbers that are preferable from the viewpoint of transmittance under the above-mentioned conditions include the following: 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole (RUVA-93, molecular weight 323.0, manufactured by Otsuka Chemical Co., Ltd.), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (Tinuvin 900, manufactured by BASF, Adeka STAB LA-24, manufactured by Adeka Corporation, EVERSORB 76 / EVERSORB 234, molecular weight 447, manufactured by Everlight Chemical Co., Ltd.), 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (Tinuvin 928, manufactured by BASF, EVERSORB 234, molecular weight 447, manufactured by Everlight Chemical Co., Ltd.), 89 / 89FD, molecular weight 442), 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (BASF Tinuvin 405, molecular weight 584), 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis-butyloxyphenyl)-1,3,5-triazine (BASF Tinuvin 460, molecular weight 630).

[0059] The UV transmittance of the cured product in this specification is a value obtained by reflectance measurement spectroscopy. Specifically, the transmittance is measured under the following conditions using a cured product film having a thickness of about 50 μm, which is prepared by sandwiching the film between PET resin sheets, and using a reflectance spectrometer (V-650 manufactured by JASCO Corporation).

[0060] Cell length: 10mm Photometric mode: T (Transmittance) Measurement range: 450-200nm Data capture interval: 1 nm UV / vis bandwidth: 2.0nm Response:medium Scanning speed: 40nm / min Light source switching: 340nm Light source: D2 / WI Filter switching: Step Correction: Baseline

[0061] The amount of the UV absorber (D) is preferably 0.01 to 5 parts by mass, and more preferably 0.5 to 2.5 parts by mass, per 100 parts by mass of the total of the components (A) and (B). If it is 0.01 part by mass or more, a sufficient UV laser peeling speed can be obtained, and if it is 5 parts by mass or less, the effect of low outgassing properties and heat resistance not being easily impaired can be obtained.

[0062] The weight average molecular weight in this specification is a value calculated as standard polystyrene by gel permeation chromatography (GPC). Specifically, the weight average molecular weight is determined under the following conditions by using tetrahydrofuran as a solvent, using a GPC system (SC-8010 manufactured by Tosoh Corporation), and creating a calibration curve with commercially available standard polystyrene.

[0063] Flow rate: 1.0ml / min Set temperature: 40℃ Column configuration: 1 column of "TSK guardcolumn MP(xL)" 6.0mmID x 4.0cm manufactured by Tosoh Corporation, and 2 columns of "TSK-GELMULTIPOREHXL-M" 7.8mmID x 30.0cm (16,000 theoretical plates) manufactured by Tosoh Corporation, for a total of 3 columns (total of 32,000 theoretical plates) Sample injection volume: 100 μl (sample concentration 1 mg / ml) Liquid delivery pressure: 39kg / cm 2 Detector: RI detector (differential refractive index detector)

[0064] In some embodiments of the present invention, a cured product of the above-described composition can be provided. Such curing can be performed using a light source as described below. When the cured product is in the form of a cured film having a thickness of 50 μm, it is preferable that one or more of the following conditions are satisfied, and more preferably all of them are satisfied. The following conditions can be satisfied, for example, by using a UV absorber. The light transmittance of the cured film is 70% or more in the wavelength region of 395 nm or more of the wavelength of the light source used for curing. The light transmittance of the cured film in the wavelength region of 385 nm or more and less than 395 nm of the wavelength of the light source used for curing is 20% or more. The light transmittance of the cured film at the wavelength (355 nm) of the UV laser used for UV laser peeling must be 1% or less. By satisfying these conditions, it is possible to achieve both a sufficiently high curing speed and a UV laser peeling speed for practical use. Furthermore, in addition to achieving both a sufficiently high curing speed and a UV laser peeling speed, it is possible to reduce the rate of mass loss under heating conditions after curing (or reduce the amount of outgassing under high temperature vacuum). A temporary fixing agent with such properties can be suitably used in processes including high temperature vacuum processes such as ion implantation, annealing, and electrode formation by sputtering in the back surface process after thinning.

[0065] The composition can be used as a temporary fixing resin composition, a temporary fixing adhesive, a pressure-sensitive adhesive sheet, or a temporary fixing adhesive for electronic device production. In this specification, the temporary fixing composition, the temporary fixing resin composition, and the temporary fixing adhesive are sometimes collectively referred to as a temporary fixing agent.

[0066] When the present composition is used to bond a substrate to be processed and an optically transparent support substrate (or support), the amount of energy in the visible light or ultraviolet light region (wavelength or center wavelength is preferably 350 to 405 nm, more preferably 365 to 405 nm, and most preferably 385 to 405 nm) is 1 to 20,000 mJ / cm. 2 It is preferable to irradiate so that the energy amount is 1 mJ / cm 2 Above this level, sufficient adhesion is obtained, and 20,000 mJ / cm 2 If the energy level is less than this, the productivity is excellent, decomposition products from the photoradical polymerization initiator are unlikely to be generated, and outgassing is suppressed. In terms of productivity, adhesion, low outgassing, and easy peeling, it is 1000 to 10000 mJ / cm 2 It is preferable that:

[0067] The substrate to be bonded by the composition is not particularly limited, but at least one of the substrates is preferably a transparent substrate that transmits light.The transparent substrate may be an inorganic substrate such as quartz, glass, quartz, calcium fluoride, magnesium fluoride, or an organic substrate such as plastic.Among these, an inorganic substrate is preferred because it is versatile and can provide a large effect.Among the inorganic substrates, one or more selected from glass and quartz are preferred.

[0068] The composition may be photocurable, and the cured product provided thereby has excellent heat resistance and peelability. In one embodiment, the cured product of the composition of the present invention has a small amount of outgas even when exposed to high temperatures, and is suitable for bonding, sealing, and coating various optical parts, optical devices, and electronic parts. The composition of the present invention is suitable for applications requiring a wide range of durability, such as solvent resistance, heat resistance, and adhesiveness, particularly for semiconductor manufacturing process applications.

[0069] The cured product of the composition can be used in processes in a wide range of temperatures from room temperature to high temperatures. The heating temperature during the process is preferably 350°C or less, more preferably 300°C or less, and most preferably 250°C or less. In a preferred embodiment, the temperature at which the heat mass loss rate of the cured product is 2% may be 250°C or more. The bonded product bonded with the composition has high shear adhesive strength and can withstand a thinning process, etc., and can be easily peeled off after a heating process such as insulating film formation. When used at high temperatures, the cured product of the composition can be used in high temperature processes, for example, preferably 200°C or more, more preferably 250°C or more.

[0070] In one embodiment, an adhesive is provided in which substrates are bonded using the composition as an adhesive. The adhesive can be peeled off by applying an external force. For example, the adhesive can be peeled off by inserting a blade, sheet or wire into the bonded portion. Alternatively, the adhesive can be peeled off by irradiating the entire surface of the adhesive from the optically transparent substrate side with a UV laser or IR laser in a scanning manner.

[0071] <Method of manufacturing thin wafer> In one embodiment, a method for producing a thin wafer can also be provided. The method is characterized in that the above-mentioned temporary fixing composition or temporary fixing adhesive (hereinafter, sometimes simply referred to as adhesive or temporary fixing agent) is used as an adhesive layer between a wafer having a semiconductor circuit or the like and a support. The method for producing a thin wafer includes the following steps (a) to (e).

[0072] [Process (a)] Step (a) is a step in which, when bonding the circuit-forming surface of a wafer having a circuit-forming surface on its front side and a circuit-free surface on its back side to a support via an adhesive, the adhesive is applied onto the support or the wafer with the circuit by a spin coating method, and then the support or the wafer with the circuit is bonded to another support or wafer with the circuit under vacuum.

[0073] A wafer having a circuit-forming surface and a non-circuit-forming surface is a wafer in which one surface is a circuit-forming surface and the other surface is a non-circuit-forming surface. The wafer to which the present invention can be applied is usually a semiconductor wafer. Examples of the semiconductor wafer include not only silicon wafers but also gallium nitride wafers, lithium tantalate wafers, lithium niobate wafers, silicon carbide wafers, germanium wafers, gallium arsenide wafers, gallium phosphide wafers, and gallium arsenide aluminum wafers. The thickness of the wafer is not particularly limited, but is preferably 600 to 800 μm, more preferably 625 to 775 μm. For example, a transparent substrate that transmits light is used as the support.

[0074] [Step (b)] Step (b) is a step of photocuring the adhesive. After the wafer processed body (laminate substrate) is formed, the adhesive is photocured with a visible light or ultraviolet light region (wavelength or center wavelength is preferably 350 to 405 nm, more preferably 365 to 405 nm, and most preferably 385 to 405 nm) with an energy amount of 1 to 20,000 mJ / cm. 2 It is preferable to irradiate so that the energy amount is 1 mJ / cm 2 Above this level, sufficient adhesion is obtained, and 20,000 mJ / cm2 If the energy is less than this, the productivity is excellent, decomposition products from the photoradical polymerization initiator are unlikely to be generated, and outgassing is also suppressed. In terms of productivity, adhesion, low outgassing, and easy peeling, the energy is 1000 to 10000 mJ / cm 2 is more preferred.

[0075] When curing the composition, black light, UV-LED, or visible light-LED can be used as a light source, and for example, the following light sources can be used. As black light, light containing a component with a wavelength of 385 nm or more is preferably used, regardless of its central wavelength. In addition, when a wavelength range is described in this specification, whether or not the central wavelength is included in the range is used to determine whether or not the range is included. Black light (center wavelength 365 nm, illuminance 10 mW / cm 2 , Toyo Adtec Co., Ltd. TUV-8271) ·UV-LED (wavelength 385±5nm, illuminance 350mW / cm 2 (Conditions: Working distance from the tip of the mirror unit is 20mm, HOYA H-4MLH200-V2-1S19 + specially designed mirror unit) ·UV-LED (wavelength 395±5nm, illuminance 375mW / cm 2 (Conditions: Working distance from the tip of the mirror unit is 20mm, HOYA H-4MLH200-V3-1S19 + specially designed mirror unit) ·UV-LED (wavelength 405±5nm, illuminance 400mW / cm 2 (Conditions: Working distance from the tip of the mirror unit is 20mm, HOYA H-4MLH200-V4-1S19 + specially designed mirror unit) ·UV-LED (center wavelength 405nm, illuminance 10mW / cm 2 , CCS HLDL-120V0-NWPSC) ·Visible light-LED (wavelength 451±5nm, illuminance 550mW / cm 2 (Condition: Work distance from the tip of the irradiation unit is 10 mm, CCS HLDL-155VL450‐PSC) ·Visible light-LED (wavelength 492±5nm, illuminance 400mW / cm 2 (Condition: Work distance from the tip of the irradiation unit is 10 mm, CCS HLDL-155BG-PSC)

[0076] In a preferred embodiment, the light source may be a UV-LED or a visible light-LED, which requires a smaller integrated amount of light (shorter irradiation time) than a black light, which generally has a broad irradiation wavelength and therefore requires a larger integrated amount of light and a longer irradiation time. In other words, by using an LED light source with a narrow irradiation wavelength band, temporary fixing can be performed in a short time, and as a result, the time required for the manufacturing process can be shortened.

[0077] [Process (c)] Step (c) is a step of grinding and / or polishing the non-circuit-forming surface of the wafer bonded to the support, i.e., a step of grinding the back side of the wafer of the wafer processed body obtained by bonding in step (a) to reduce the thickness of the wafer. The thickness of the thinned wafer is preferably 10 to 300 μm, more preferably 30 to 100 μm. There is no particular restriction on the method of grinding / polishing the back side of the wafer, and a known grinding / polishing method is adopted. Grinding is preferably performed while cooling by pouring water on the wafer and grindstone (such as a diamond-edged grindstone).

[0078] [Step (d)] Step (d) is a step of processing the non-circuit-forming surface of the wafer processed body with the non-circuit-forming surface ground / polished, i.e., the wafer processed body thinned by back grinding / polishing. This step includes various processes used at the wafer level. For example, electrode formation, metal wiring formation, protective film formation, etc. More specifically, conventionally known processes include metal sputtering for forming electrodes, etc., wet etching for etching the metal sputtering layer, application of resist as a mask for metal wiring formation, exposure, and development to form a pattern, resist peeling, dry etching, formation of metal plating, silicon etching for TSV formation, and oxide film formation on the silicon surface.

[0079] [Step (e)] Step (e) is a peeling step. This step is a step of peeling off the wafer processed in step (d) from the wafer processed body. For example, after various processing is performed on the thinned wafer, the wafer is peeled off from the wafer processed body before dicing. At this time, a dicing tape can be attached to the thinned and processed surface in advance. This peeling step is generally performed under relatively low temperature conditions, from room temperature to about 60°C. As this peeling step, any of the well-known UV laser peeling step, IR laser peeling step, and mechanical peeling step can be adopted.

[0080] The UV laser peeling process is, for example, a process in which a UV laser is irradiated onto the entire surface of the wafer processed body so as to scan linearly back and forth in a tangential direction from the end of the optically transparent support side of the wafer processed body, and the adhesive layer is decomposed by the energy of the laser to peel it off. Such a peeling process is described, for example, in JP-T-2019-501790 and JP-T-2016-500918.

[0081] The IR laser peeling step is, for example, a step of irradiating the entire surface of the wafer processed body with an IR laser so as to scan linearly back and forth in a tangential direction from the end of the optically transparent support side of the wafer processed body, and heating and decomposing the adhesive layer by the energy of the laser to peel it off. Such a peeling step is described, for example, in Japanese Patent No. 4565804. In order to carry out this IR laser peeling step, a light-to-heat conversion layer (for example, 3M's LTHC; Light-To-Heat-Conversion release coating) that absorbs IR laser light and converts it to heat may be provided between the temporary fixing agent layer and the glass support. When using 3M's LTHC, for example, LTHC is spin-coated on the glass support and cured. Then, the temporary fixing agent layer can be spin-coated on the wafer, and then bonded to the glass support on which the LTHC layer is formed, and UV-cured. A method of carrying out the IR laser peeling step using 3M's LTHC is described, for example, in the same Japanese Patent No. 4565804 as above.

[0082] The mechanical peeling process is, for example, a peeling process including a process in which a blade is inserted into the interface end of a wafer processed body to generate a cleavage between the wafer and the support, the wafer of the wafer processed body is fixed horizontally with the wafer facing down, and after the blade is inserted, an upward stress is applied to the upper support and / or the blade to develop the cleavage and peel off the wafer and the support. Such a peeling process is described, for example, in Japanese Patent No. 6377956 and Japanese Patent Laid-Open No. 2016-106404.

[0083] Any of these peeling methods can be used to peel off the composition. At this time, it is preferable to fix one of the wafer or support of the wafer processed body horizontally, insert a blade or use a solvent (e.g., an aliphatic or aromatic hydrocarbon solvent such as pentane, hexane, heptane, octane, nonane, decane, benzene, toluene, xylene, mesitylene, etc.) to swell the outer periphery of the adhesive layer to trigger peeling, and then lift the other side at a certain angle from the horizontal direction. These peeling methods are usually performed at room temperature, but it is also preferable to heat the laser to a maximum of about 90°C. When a laser is used, a YAG laser or a YVO 4 It is preferred to use a laser.

[0084] The step of peeling the processed wafer from the support in the above step (e) further includes, in the case of a mechanical peeling step, (f) adhering a dicing tape to the wafer surface of the processed wafer; (g) vacuum-adsorbing the dicing tape surface onto the adsorption surface; (h) peeling the support from the processed wafer while the temperature of the adsorption surface is in the range of 10 to 100° C.; In this way, the support can be easily peeled off from the processed wafer, and the subsequent dicing step can be easily carried out.

[0085] In addition, in the case of peeling with a UV laser or an IR laser, the manufacturing method further includes, for example: (i) placing / fixing the processed wafer, optically transparent support side up, on a horizontal surface, preferably via a dicing tape; (j) irradiating the entire surface of the processed wafer with a laser from the support side of the wafer in a scanning manner; In this way, the support can be easily peeled off from the processed wafer, and the subsequent dicing step can be easily carried out.

[0086] In addition, after the step of peeling the processed wafer from the support by a UV laser or an IR laser in step (e), (k) removing the temporary fixing agent remaining on the surface of the wafer; It is necessary to carry out the above. Methods for removing the temporary fixing agent include a method in which, while the thinned surface is vacuum-adsorbed onto the adsorption surface, an adhesive tape such as a dicing tape is applied to the entire surface of the other surface on which the temporary fixing agent remains, and the temporary fixing agent is peeled off together with the tape, and a method in which the wafer is immersed in a solvent (e.g., an aliphatic or aromatic hydrocarbon solvent such as pentane, hexane, heptane, octane, nonane, decane, benzene, toluene, xylene, mesitylene, etc.) to swell the adhesive layer and peel it off. Of these methods, the tape peeling method is preferred in terms of the small number of steps and the short time required.

[0087] After the temporary fixing agent is removed, the wafer can be directly subjected to the next process without cleaning the surface. (l) A process of cleaning the wafer from which the support and temporary fixing agent have been removed, with the circuit-forming surface facing up, using a solvent (e.g., an aliphatic or aromatic hydrocarbon solvent such as pentane, hexane, heptane, octane, nonane, decane, benzene, toluene, xylene, or mesitylene). It is preferable to carry out the following.

[0088] In the step (k), the adhesive (temporary fixing agent) may remain partially on the circuit formation surface of the wafer from which the temporary fixing agent has been removed. In addition, it is preferable to wash and reuse the peeled support, but adhesive residues may also be attached to the surface of the support. Methods for removing these adhesive residues include a method of immersing the support in a solvent (e.g., an aliphatic or aromatic hydrocarbon solvent such as pentane, hexane, heptane, octane, nonane, decane, benzene, toluene, xylene, or mesitylene) and swelling the support to peel it off.

[0089] In one embodiment, various techniques such as those described below can be used to cure the composition to obtain a cured product.

[0090] As a first method, a layer made of a temporary fixing composition containing the above-mentioned components can be cured to obtain a single-layer cured body.

[0091] The second method is to prepare a first layer made of a temporary fixing composition containing at least the components (A) to (C) and not containing a UV absorber (D), and a second layer made of a temporary fixing composition containing at least the components (A) to (D), and to cure the first layer to obtain a cured body having an integrated single layer or multiple layers (composite layers). In this cured body, it is preferable that the concentration distribution of the components is different in the thickness direction, or that the concentration distribution of the components is different on the upper and lower surfaces in the thickness direction of the cured body. The difference in the concentration distribution of the components can be confirmed by quantifying the UV transmittance on both sides of the cured body using the reflectance measurement spectroscopy described above. This method provides the effect of combining layers with different light transmittances to realize optimal curing. In addition, a black light or a UV-LED can be used as a light source for the above-mentioned curing (the same applies to the method described below). An example of a black light is TUV-8271 (center wavelength 365 nm, illuminance 10 mW / cm) manufactured by Toyo Adtec Co., Ltd. 2 ) as UV-LED. HOYA Corporation's H-4MLH200-V2-1S19 + specially designed mirror unit (wavelength 385±5nm, illuminance 350mW / cm2 ,Conditions: Scan pitch from the tip of the mirror unit 20 mm), HOYA Corporation H-4MLH200-V3-1S19 + specially designed mirror unit (wavelength 395 ± 5 nm, illuminance 375 mW / cm 2 ,Conditions: Working distance from the tip of the mirror unit 20 mm), HOYA Corporation H-4MLH200-V4-1S19 + specially designed mirror unit (wavelength 405 ± 5 nm, illuminance 400 mW / cm 2 , Conditions: Working distance from the tip of the mirror unit is 20 mm.

[0092] As a third method, a layer of a commercially available LTHC agent (light-to-heat conversion agent) may be placed on a layer of a temporary fixing composition containing at least the components (A) to (C) and cured to obtain a multi-layer cured body. This has the effect of easily obtaining a cured body.

[0093] The cured product obtained by the above-mentioned method can be combined with an adherend to provide a structure.

[0094] There are various examples of the method for producing the structure as described above. For example, the first production method may include a step of applying a first temporary fixing composition containing at least the components (A) to (C) but not the component (D) on a wafer and partially curing the composition, a step of applying a second temporary fixing composition containing at least the components (A) to (D) on the partially cured temporary fixing composition, and a step of further placing a transparent substrate on the applied second temporary fixing composition and photocuring the composition.

[0095] In addition, a second manufacturing method of the structure may include a step of applying a first temporary fixing composition containing at least the (A) to (C) components but not containing the (D) component onto a wafer and partially curing it as necessary, a step of applying a second temporary fixing composition containing at least the (A) to (D) components onto a transparent substrate and partially curing it as necessary, and a step of bringing the surfaces of the wafer and the transparent substrate onto which the temporary fixing compositions are applied into close contact with each other, and then bonding them by photocuring.

[0096] In addition to the above-mentioned temporary fixing composition, the same composition used in the temporary fixing composition of the present invention can also be used as a raw material for the light-to-heat conversion (LTHC) layer that absorbs IR laser light and converts it into heat, as described in Japanese Patent No. 4565804. By adding this composition as a component of the light-to-heat conversion (LTHC) layer, it is possible to improve its heat resistance.

[0097] In one embodiment, a method for producing a semiconductor wafer can be provided, which includes the steps of applying a temporary fixing composition to a semiconductor wafer substrate and / or a support member to bond the semiconductor wafer substrate and the support member, curing the temporary fixing adhesive by irradiating light with a wavelength of 350 to 700 nm (preferably 365 to 500 nm, more preferably 385 to 450 nm) to obtain an adhesive body, and irradiating the adhesive body with laser light with a wavelength of less than 385 nm (preferably laser light with a wavelength of 200 nm or more and less than 385 nm) to peel off the semiconductor wafer substrate. This production method has the advantages that both the curing and peeling steps are performed at room temperature, there is no need to heat or cool the members, there is generally no need to use a solvent, and the method is simple and has a short cycle time.

[0098] Furthermore, the cured temporary fixing adhesive may form a single layer in the adhesive body, which makes it possible to simplify the process and shorten the tact time.

[0099] In a preferred embodiment, the composition contains both the photoradical polymerization initiator (C) and the UV absorber (D), so that even a single-layer temporary fixing adhesive can achieve both a fast curing rate and a fast peeling rate. Furthermore, when the temporary fixing adhesive is UV-cured, the amount of uncured UV-curable monomer components remaining in the cured body can be significantly reduced, improving the heat resistance of the cured body and reducing the volatile content under a nitrogen atmosphere. That is, for example, it is possible to increase the 2% heat mass loss temperature in the Tg / DTA measurement of the cured body. A temporary fixing adhesive with high heat resistance of the cured body and reduced volatile content under a nitrogen atmosphere is extremely useful for recent semiconductor manufacturing processes. The cured body may preferably have a 2% mass loss temperature of 300° C. or higher, preferably 320° C. or higher, more preferably 326° C. or higher under a nitrogen atmosphere.

[0100] In one embodiment, a method for producing a substrate for an electronic device can be provided. The method may include the steps of mixing a monofunctional (meth)acrylate, a polyfunctional (meth)acrylate, and a photoradical polymerization initiator to prepare a composition having a viscosity of 500 to 10,000 mPa·s at 23°C, applying the prepared composition onto a silicon wafer by spin coating to make the surface of the applied composition flat with a height difference of 40 μm or less, and adhering a support to the silicon wafer so as to sandwich the applied composition. In this specification, the flatness of the composition surface is measured after the composition is applied by a spin coater and cured under the conditions described in the examples described later. EXAMPLES

[0101] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to these.

[0102] Unless otherwise specified, the experiments were performed at 23°C and 50% humidity. Curable resin compositions (hereinafter sometimes referred to as liquid resin compositions) having the compositions (units: parts by mass) shown in the table below were prepared and evaluated. The following compounds were selected as each component.

[0103] [Table 1]

[0104] [Table 2]

[0105] (composition) The following was used as component (A). Surface tension values ​​were measured at 23° C. by the ds / de method using an "OCA20" manufactured by Eiko Seiki Co., Ltd. The surface tension of the entire composition was also measured in the same manner. LA: Lauryl acrylate ("LA" manufactured by Osaka Organic Chemical Industry Co., Ltd., surface tension 29.3 mN / m) NOAA: n-octyl acrylate ("NOAA" manufactured by Osaka Organic Chemical Industry Co., Ltd., surface tension 27.5 mN / m) INAA: Isononyl acrylate ("INAA" manufactured by Osaka Organic Chemical Industry Co., Ltd., surface tension 27.5 mN / m) ISTA: Isostearyl acrylate ("ISTA" manufactured by Osaka Organic Chemical Industry Co., Ltd., surface tension 26.3 mN / m) ACMO: Acryloylmorpholine (KJ Chemicals' "ACMO", surface tension 44.6 mN / m)

[0106] The following was used as component (B). Viscosity values ​​and solid state values ​​are those at 23°C. HX-620: Caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate ("Kayarad HX-620" manufactured by Nippon Kayaku Co., Ltd., m+n≒4, (average) molecular weight 768, viscosity 290 mPa s) HX-220: Caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate ("Kayarad HX-220" manufactured by Nippon Kayaku Co., Ltd., m+n≒2, (average) molecular weight 541, viscosity 120 mPa s) A-BPEF-2: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene diacrylate ("NK Ester A-BPEF-2" manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight 546, high viscosity exceeding the measurement limit, judged to be a viscosity of more than 1000 mPa s) RA-341: Multifunctional methacrylate polymer ("ART CURE RA-341" manufactured by Negami Chemical Industries, weight average molecular weight of the backbone polymer is approximately 70,000, viscosity is higher than the measurement limit, and viscosity is judged to be more than 1000 mPa s) A-BPE-2: Ethoxylated bisphenol A diacrylate ("NK Ester A-BPE-2" manufactured by Shin-Nakamura Chemical Co., Ltd., in the following structural formula, R = -CH 2 CH 2 O-, m=n=1, molecular weight 422, solid at 23°C)

[0107] [ka] RC100C: Acrylate polymer with acryloyl groups at both ends (Kaneka XMAP RC100C manufactured by Kaneka Corporation, structural formula below, weight average molecular weight 24000, high viscosity exceeding the measurement limit, judged to be viscosity over 1000 mPa s)

[0108] [ka]

[0109] As other components, the following were used for comparative examples. Tetrax 6T: Polyisobutylene (ENEOS "Tetrax Grade 6T", viscosity average molecular weight 60,000) A-DCP: Tricyclodecane dimethanol diacrylate ("NK Ester A-DCP" manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight 304, viscosity 160 mPa s) DCP: Tricyclodecane dimethanol dimethacrylate ("NK Ester DCP" manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight 332, viscosity 130 mPa s)

[0110] The following was used as component (C): Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BASF "Irgacure 819")

[0111] The following was used as component (D): 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis-butyloxyphenyl)-1,3,5-triazine (BASF "Tinuvin 460") Hydroxyphenyltriazine UV absorber (BASF "Tinuvin 479") 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole (Otsuka Chemical Co., Ltd. "RUVA-93")

[0112] (Liquid sample preparation) The materials were heated and mixed at 80°C to obtain a homogeneous mixture. The viscosity of each component and the entire composition was measured using an Anton-Paar MCR302 rotational rheometer with a cone plate CP50-2 at a temperature of 23°C and a shear rate of 1 s -1 In the measurement of the viscosity of component (B) and its comparative polyfunctional (meth)acrylate, when the viscosity was too high to be measured satisfactorily using the rotational rheometer under the above measurement conditions, the viscosity was determined to be clearly over 1000 mPa s (estimated high viscosity of over 100,000 mPa s).

[0113] (Measurement of 2% mass loss temperature) The liquid resin composition homogenized by the above-mentioned warm mixing was sandwiched between PET films and spread to a thickness of 70 μm. The accumulated light dose was 5000 mJ / cm 2 The curing was performed under the above conditions to prepare a cured sample. A UV-LED (center wavelength 405 nm, illuminance 100 mW / cm2) was used for curing.2 The wafer UV irradiator (MUVBA-0.4×0.6×0.2‐0010, manufactured by ITEC Systems) was used.

[0114] The weighed 10 mg sample of the cured body was heated from room temperature to 600°C at a heating rate of 10°C / min under a nitrogen flow with a carrier gas flow rate of 70 ml / min using a Netsch Japan Co., Ltd. STA-2500 differential thermal and thermogravimetric simultaneous measurement device, and then the cured body was weighed. From this, the thermal mass loss rate (2% mass loss temperature) in a nitrogen atmosphere was calculated.

[0115] (Evaluation of vacuum heat resistance) Using the liquid resin composition thus prepared, a 4-inch silicon wafer (diameter 10 cm × thickness 525 μm) and a 4-inch glass wafer (diameter 10 cm × thickness 0.7 mm) were bonded together to produce a 4-inch sample. When bonding, the thickness of the resin composition was adjusted by adding 0.1 mass% of glass beads (product name SPL-70, average particle size 70 μm) manufactured by Unitika Ltd. to the temporary fixing agent and mixing it. After bonding, the LED accumulated light quantity was 5000 mJ / cm. 2 (Center wavelength 405nm, illuminance 100mW / cm 2 ) to prepare a bonded sample. 2 The bonded samples were evaluated for vacuum heat resistance, as described below.

[0116] Each bonded sample was placed in a vacuum hot plate chamber and heated at 300° C. and 20 Pa for 1 hour, after which the circumferential edge of the silicon wafer was visually observed and evaluated according to the following criteria. Excellent: The edges were not peeled off at all. Good: The length of the peeled portion at the end was less than 5 mm from the edge. Passable: The length of the peeled end was 5mm or more but less than 10mm from the edge. Unacceptable: The length of the peeled off edge was 10 mm or more from the edge.

[0117] (Evaluation of laser peelability) The 4-inch bonded sample prepared as described above was irradiated with a UV laser over an area of ​​210 mm square fixed at the center of the test specimen, scanning the entire surface of the specimen from the glass support side. The UV laser irradiation conditions are shown below. The UV laser used was a Keyence MD-U1020C. Irradiation was performed under the following conditions: output 2.5 W, frequency 40 kHz, beam diameter 72 μm, scan pitch 150 μm, and scan speed 6 m / sec. Peelability after irradiation was evaluated according to the following definition. The glass support was rated "Excellent" when it was in a state where it was able to be easily peeled off by hand from the temporary fixative without any adhesion. If the glass support still had some adhesiveness but could be peeled off by hand from the temporary fixative, it was rated "good." Glass supports that cannot be peeled off by hand from the temporary fixative are categorized as "unacceptable."

[0118] (Edge bead height evaluation) 6.5 to 7.5 g of the prepared resin composition was applied onto an 8-inch Si wafer using a spin coater (MS-A300 manufactured by Mikasa Co., Ltd.), rotated at a low speed (50 rpm x 15 sec), and then rotated at a high speed under the following conditions to spread the liquid evenly. The upper surface was moved into a glass chamber, the chamber interior was replaced with a nitrogen atmosphere, and the LED integrated light intensity was 8100 mJ / cm. 2 (Center wavelength 405nm, illuminance 45mW / cm 2 The thickness of the edge bead was measured at the thickest part of the edge and at a part 2 cm or more inside from the edge, and the difference between the thicknesses was taken as the edge bead height. High speed rotation conditions Rotation time: 15 seconds Rotation speed: Nrpm (using the viscosity value and the formula below, the condition rotation speed at which the thickness is 74 to 76 μm when the application time is 15 seconds) Application amount: 6.5~7.5g calculation formula h = h0 / {1 + t × (4ω2 h0 2 / 3ν)} 1 / 2 h: film thickness [mm], h0: initial film thickness [mm], ω: rotation speed [rad / sec], t: Time [sec], ν: Kinematic viscosity [mm 2 / sec] Rotational speed ω=πN / 30 ω: Rotational speed [rad / sec], rotational speed [rpm] kinematic viscosity ν=μ / ρ ν: kinematic viscosity [m 2 / sec], μ: Viscosity [Pa s], ρ: Density [kg / m 3 ] Initial film thickness h0={w / (s×ρ)}×10 h0: initial film thickness [mm], w: coating amount [g], s: wafer area [cm 2 ], ρ: density [g / cm 3 ]

[0119] From the above results, in all of the compositions according to the examples of the present invention, the edge bead height was suppressed to 40 μm or less, and both the laser releasability and heat resistance were good. On the other hand, in Comparative Examples 1 and 2 not containing the component (A), the edge bead was high and the inclusion of air bubbles could not be prevented. Comparative Examples 3 and 5 not satisfying the surface tension conditions of the component (A) also had high edge bead. Comparative Example 4 not containing the component (B) had poor laser releasability and was not suitable for practical use.

Claims

1. The composition contains the following (A) to (C), and is viscoelastic at 23°C and a shear rate of 1 s measured by a rotational rheometer. -1 The temporary fixing composition has a viscosity in the range of 500 to 10,000 mPa·s under atmospheric pressure. (A) A monofunctional (meth)acrylate having a surface tension in the range of 20 to 30 mN / m as measured by the ds / de method using the pendant drop method at 23°C. (B) Rheological properties measured by a rotational rheometer at 23° C. and a shear rate of 1 s -1 or the viscosity at atmospheric pressure is 1000 mPa·s or more, or the material is solid at 23°C, or the molecular weight is 500 or more and the viscosity at atmospheric pressure is 1000 mPa·s or more ... molecular weight is 500 or more, or the molecular weight is 500 or more, or the molecular weight is 500 -1 A polyfunctional (meth)acrylate having a viscosity of 100 mPa·s or more and less than 1000 mPa·s at atmospheric pressure. (C) Photoradical polymerization initiator

2. In the mass ratio of the (A) component to the (B) component, the amount of the (A) component is in the range of 5 to 65%. The temporary fixing composition according to claim 1 .

3. The temporary fixing composition according to claim 1 or 2, wherein the component (A) is an aliphatic monofunctional (meth)acrylate.

4. The temporary fixing composition according to claim 3 , wherein the aliphatic group of the component (A) has 6 or more and 30 or less carbon atoms.

5. The temporary fixing composition according to any one of claims 1 to 4, wherein the component (B) includes an oligomer or a polymer.

6. The temporary fixing composition according to any one of claims 1 to 5, further comprising the following (D): (D) UV absorber

7. A cured product of the temporary fixing composition according to any one of claims 1 to 6.

8. The cured product according to claim 7, which has a 2% mass loss temperature of 300°C or higher in a nitrogen atmosphere.

9. A method for producing a substrate for an electronic device, comprising the steps of: A step of mixing a monofunctional (meth)acrylate, a polyfunctional (meth)acrylate, and a photoradical polymerization initiator to prepare a composition having a viscosity at 23°C in the range of 500 to 10,000 mPa·s; A step of applying the prepared composition onto a silicon wafer by a spin coating method so that the surface of the applied composition is flat with a height difference of 40 μm or less; Adhering a support to the silicon wafer so as to sandwich the applied composition; A manufacturing method comprising:

10. A temporary fixing adhesive comprising the temporary fixing composition according to any one of claims 1 to 6.

11. A bonded body comprising the temporary fixing adhesive according to claim 10 and a substrate bonded by the temporary fixing adhesive.

12. A method for producing a thin wafer, using the temporary fixing adhesive according to claim 10.

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