KR102731754B1 - Adhesive tape - Google Patents

Abstract

The present invention aims to provide an adhesive tape which protects an adherend even when used in a process involving high-temperature treatment of up to 260°C, and which can be peeled off without leaving a residue. The present invention is an adhesive tape having a substrate film and an ultraviolet-curable adhesive layer laminated on one side of the substrate film, wherein after irradiating the surface of the substrate film side of the adhesive tape with 405 nm ultraviolet rays at 3000 mJ/cm2, the gel fraction of the ultraviolet-curable adhesive layer is 90% or more, and when the tensile modulus of the adhesive tape at X°C is Et (X) after irradiating the surface of the substrate film side of the adhesive tape with 405 nm ultraviolet rays at 3000 mJ/cm2, the value of Et (270) is 1.0 × 10 ⁷ Pa or more.

Description

Adhesive tape

The present invention relates to an adhesive tape.

In the manufacturing process of semiconductor chips, adhesive tapes are used to facilitate handling of wafers or semiconductor chips during processing and to prevent damage. For example, when a thick film wafer cut from a high-purity silicon single crystal is ground to a predetermined thickness to make a thin film wafer, an adhesive tape is bonded to the thick film wafer and then the grinding is performed.

The adhesive composition used in such adhesive tapes is required to have high adhesiveness that can firmly fix an adherend such as a wafer or semiconductor chip during a processing process, and also to be able to peel off the adherend such as a wafer or semiconductor chip after the processing is completed without damaging it (hereinafter also referred to as “high adhesion peelability”).

As an adhesive composition realizing high adhesion and easy peeling, Patent Document 1 discloses an adhesive tape using a photocurable adhesive that hardens by irradiating with light such as ultraviolet rays and has a reduced adhesive strength. By using a photocurable adhesive as the adhesive, an adherend can be reliably fixed during a processing process, and the adhesive can be easily peeled by irradiating with ultraviolet rays or the like.

Japanese Patent Publication No. 5-32946

Recently, due to the thinning and miniaturization of semiconductor products, semiconductor devices in which a large number of semiconductor chips are stacked on a wafer are being manufactured. In the manufacture of semiconductor devices in which a large number of semiconductor chips are stacked, the semiconductor chips are fixed on the wafer or semiconductor chips by a thermal compression bonding process while the wafer or semiconductor chips are protected by adhesive tape.

The inventors of the present invention have found that since a high temperature exceeding the conventional high temperature treatment of 260°C is applied in thermocompression bonding, even an adhesive tape using a conventional curable adhesive cannot withstand the heat of the high temperature treatment and the base film of the adhesive tape shrinks, and the adhesive layer is pulled together by the shrinkage, causing the adhesive tape to peel off. In addition, since pressure is also applied in thermocompression bonding in addition to the high temperature, the adhesive easily progresses and glue residue easily occurs. In addition, wafers on which the thermocompression bonding process is performed often have large bumps formed on the adhesive tape's bonding surface, and if the adhesive gets caught in the inner part of the irregularities, it is torn off in small pieces during peeling and glue residue occurs.

The purpose of the present invention is to provide an adhesive tape that protects an adherend and can be peeled off without leaving any residue even when used in a process involving high-temperature treatment of up to 260°C.

The present invention is an adhesive tape having a base film and an ultraviolet-curable pressure-sensitive adhesive layer laminated on one side of the base film, wherein after irradiating the surface of the base film side of the adhesive tape with 405 nm ultraviolet rays at 3000 mJ/cm2, the gel fraction of the ultraviolet-curable pressure-sensitive adhesive layer is 90% or more, and when the tensile elastic modulus at X°C of the adhesive tape is Et (X) after irradiating the surface of the base film side of the adhesive tape with 405 nm ultraviolet rays at 3000 mJ/cm2, the value of Et (270) is 1.0 × 10 ⁷ Pa or more.

The present invention is described in detail below.

The adhesive tape of the present invention has an ultraviolet-curable adhesive layer laminated on one side of the substrate film.

Since the adhesive tape has an ultraviolet-curable adhesive layer, it can be attached to an adherend with sufficient adhesive strength to protect the adherend, and by curing the ultraviolet-curable adhesive layer after attachment, the adherend can be protected even when high-temperature processing is performed. In addition, after protection is no longer necessary, the adhesive tape can be easily peeled off without leaving any adhesive residue.

The adhesive tape of the present invention has a gel fraction of the ultraviolet-curable adhesive layer of 90% or more after irradiating the surface of the substrate film side of the adhesive tape with 405 nm ultraviolet rays at 3000 mJ/cm2.

Since the gel fraction of the UV-curable adhesive layer after UV irradiation is 90% or more, it becomes difficult for adhesion promotion to progress even at high temperatures, so that the adhesive tape can be peeled off without residue after protection becomes unnecessary. In addition, the chemical resistance of the adhesive tape can also be improved. In addition, if the UV-curable adhesive layer can be cured by irradiating the surface of the substrate film side with UV rays, the UV-curable adhesive layer can be cured after the adhesive tape is bonded to the adherend. From the viewpoint of further improving the adhesion promotion inhibition property and chemical resistance of the adhesive tape, the gel fraction of the UV-curable adhesive layer after UV irradiation is preferably 93% or more, more preferably 95% or more, and still more preferably 97% or more.

In addition, the gel fraction of the above-mentioned ultraviolet-curable adhesive layer after ultraviolet irradiation is usually 100% or less.

In addition, when the adhesive tape of the present invention has a structure in which another layer, such as an adhesive layer, is laminated on the other side of the base film, the base film side refers to the side opposite to the side of the base film on which the ultraviolet-curable adhesive layer is laminated.

The adhesive tape of the present invention has a tensile elastic modulus at X ℃ of the adhesive tape after irradiating the surface of the substrate film side of the adhesive tape with 3000 mJ/cm2 of 405 nm ultraviolet rays, whereby the value of Et (270) is 1.0 × 10 ⁷ Pa or more.

Since the adhesive tape after ultraviolet irradiation has a tensile elastic modulus in the above range at 270°C, an adhesive tape having excellent heat resistance can be obtained, and even when subjected to high-temperature treatment up to 260°C, the adhesive tape is unlikely to soften or shrink, thereby suppressing unintended peeling of the adhesive tape. The preferable lower limit of the Et (270) is 3.0 × 10 ⁷ Pa, a more preferable lower limit is 5.0 × 10 ⁷ Pa, and a further preferable lower limit is 1.0 × 10 ⁸ Pa. The upper limit of the Et (270) is not particularly limited, but is preferably 1.0 × 10 ⁹ Pa from the viewpoint of handleability of the adhesive tape.

In addition, the tensile elastic modulus of the adhesive tape can be measured by the following method.

By irradiating the UV-curable pressure-sensitive adhesive layer with 405 nm ultraviolet rays from the surface of the base film side so that the accumulated intensity becomes 3000 mJ/cm2, the UV-curable pressure-sensitive adhesive layer is cured. Then, a 5 mm × 35 mm test piece is produced by stamping using a stamping blade so that the long side is the same as the flow direction at the time of tape manufacture. The obtained test piece is immersed in liquid nitrogen and cooled to -50 °C, and thereafter, using a viscoelasticity spectrometer (DVA-200, manufactured by IT Instrumentation and Control Co., Ltd., or its equivalent), the temperature is increased to 300 °C under the conditions of 10 °C/min, frequency 10 Hz in constant-rate temperature-rise tensile mode, and the tensile modulus is measured. The value of the tensile modulus (E') at the temperature X °C at this time is taken as Et (X). That is, the value of the tensile elastic modulus (E') at a temperature of 270 ℃ becomes Et (270).

It is preferable that the adhesive tape of the present invention has a value of Et (270)/Et (200) of 0.1 or more.

Since the difference between the tensile elastic modulus at 270°C and the tensile elastic modulus at 200°C of the adhesive tape after ultraviolet irradiation is small, an adhesive tape having better heat resistance can be made, and unintended peeling of the adhesive tape can be further suppressed. From the viewpoint of further suppressing the peeling, the value of Et (270) / Et (200) is more preferably 0.2 or more, further preferably 0.3 or more, and particularly preferably 0.5 or more. The upper limit of the value of Et (270) / Et (200) is not particularly limited, and the closer it is to 1, the better, but it is usually 1 or less, and preferably less than 0.8.

The adhesive tape of the present invention preferably has a weight reduction rate of 5% or less when the surface of the substrate film side of the adhesive tape is irradiated with 3000 mJ/cm2 of ultraviolet rays of 405 nm, the temperature is increased from 25°C to 280°C at a rate of 5°C min, and the temperature is held for 10 minutes.

Since the weight loss at a high temperature of 280℃ is small, that is, it is difficult to cause thermal decomposition at a high temperature, the amount of outgas generated by thermal decomposition is small, and the outgas collected at the interface between the adherend and the adhesive tape can be suppressed from becoming a starting point for peeling. From the viewpoint of suppressing peeling at a high temperature, the weight loss rate is more preferably 4% or less, further preferably 3% or less, and usually 0% or more.

Additionally, the weight reduction rate can be measured by the following method.

By irradiating the UV-curable pressure-sensitive adhesive layer with 405 nm ultraviolet rays from the surface of the base film side so that the accumulated intensity becomes 3000 mJ/cm2, the UV-curable pressure-sensitive adhesive layer is cured. Next, the adhesive tape is stamped into a φ5 mm circle to produce a measurement sample. The weight of the obtained measurement sample is measured, and the measurement is performed using a differential thermal gravimetric simultaneous measurement device (TG-DTA; STA7200, manufactured by Hitachi High-Tech Science Co., Ltd., or its equivalent). The heating rate is 5 °C/min, the temperature is increased from 25 °C to 280 °C, and the weight of the measurement sample maintained at 280 °C for 10 minutes is measured. The weight reduction rate can be calculated from the weight before and after heating.

It is preferable that the above-mentioned film have an ultraviolet ray transmittance of 1% or more at 405 nm.

Since the 405 nm ultraviolet transmittance of the base film is 1% or more, the ultraviolet-curable pressure-sensitive adhesive layer can be cured beyond the base film, making it easy to adjust the gel fraction of the ultraviolet-curable pressure-sensitive adhesive layer after the ultraviolet irradiation. As a result, glue residue on the adherend due to adhesion promotion can be suppressed. The ultraviolet transmittance is more preferably 10% or more, further preferably 50% or more, and particularly preferably 70% or more. Since the ultraviolet transmittance is equal to or more than these lower limits, the ultraviolet-curable pressure-sensitive adhesive layer can be sufficiently cured without using a photosensitizer. The upper limit of the ultraviolet transmittance is not particularly limited, the higher the better, and is usually 100% or less.

In addition, the ultraviolet transmittance can be measured using a spectrophotometer (U-3900, manufactured by Hitachi, Ltd., or its equivalent). More specifically, the measurement can be made in the range of 800 to 200 nm at a scan speed of 300 nm/min and a slit spacing of 4 nm, and the transmittance at 405 nm can be measured.

The above-described film preferably has a value of Ef (270) of 5.0 × 10 ⁷ Pa or more, when the tensile elastic modulus at X ℃ is represented by Ef (X).

When the tensile elastic modulus of the above-mentioned base film at 270° C. is within the above-mentioned range, an adhesive tape having superior heat resistance can be made, and peeling due to heat shrinkage or softening of the base film during high-temperature processing can be suppressed. A more preferable lower limit of the above-mentioned Ef (270) is 1.0 × 10 ⁸ Pa, a further preferable lower limit is 5.0 × 10 ⁸ Pa, and a particularly preferable lower limit is 1.0 × 10 ⁹ Pa. The upper limit of the above-mentioned Ef (270) is not particularly limited, but is preferably 1.0 × 10 ¹⁰ Pa from the viewpoint of handleability of the adhesive tape.

Additionally, the tensile modulus of the above-described film can be measured by the same method as the tensile modulus of the above-described adhesive tape.

The above-mentioned base film is not particularly limited as long as the obtained adhesive tape satisfies the tensile elastic modulus and gel fraction of the above-mentioned range, but in terms of excellent heat resistance and strength, it is preferable that the above-mentioned base film contains a resin having at least one selected from the group consisting of amide, imide, ether, and ketone in the main chain skeleton of the repeating unit.

Examples of the resin having at least one selected from the group consisting of the above amides, imides, ethers, and ketones in the main chain skeleton of repeating bond units include polyamides, polyimides, polyethers, polyketones, etc. Among these, in terms of superior heat resistance and strength, it is preferable that the above-mentioned base film contains a polyamide resin, and further, in terms of superior ultraviolet ray transmittance, it is more preferable that it contains a polyamide resin having a long-chain alkyl group or aromatic group having 4 to 12 carbon atoms in the main chain skeleton of repeating units.

Examples of polyamide resins having a long-chain alkyl group or aromatic group having 4 to 12 carbon atoms in the main chain skeleton of repeating units include nylon 9T and nylon 6T.

The thickness of the above-mentioned base film is not particularly limited, but the preferable lower limit is 25 ㎛, the more preferable lower limit is 50 ㎛, the preferable upper limit is 250 ㎛, and the more preferable upper limit is 125 ㎛. When the above-mentioned base film is within this range, an adhesive tape having excellent handling properties can be obtained.

The adhesive constituting the above-mentioned ultraviolet-curable pressure-sensitive adhesive layer is not particularly limited as long as it is ultraviolet-curable, and examples thereof include ultraviolet-curable adhesives containing a polymerizable polymer as a main component and an ultraviolet polymerization initiator as a polymerization initiator. Examples of the polymerizable polymer include (meth)acrylic polymers, urethane acrylate polymers, etc. Among these, (meth)acrylic polymers are preferable in that they are easy to satisfy the gel fraction and the Et (270), and (meth)acrylic acid alkyl ester-based polymerizable polymers having a radically polymerizable unsaturated bond in the molecule are more preferable.

The above (meth)acrylic acid alkyl ester polymerizable polymer can be obtained, for example, by pre-synthesizing a (meth)acrylic polymer having a functional group in the molecule and reacting a compound having a functional group reactive with the functional group in the molecule and an unsaturated bond capable of radical polymerization. In addition, hereinafter, a "(meth)acrylic polymer having a functional group in the molecule" is referred to as a "functional group-containing (meth)acrylic polymer", and a "compound having a functional group reactive with the functional group and an unsaturated bond capable of radical polymerization in the molecule" is referred to as a "functional group-containing unsaturated compound".

The above functional group-containing (meth)acrylic polymer is obtained by using an alkyl acrylic acid ester and/or an alkyl methacrylic acid ester having an alkyl group of usually 2 to 18 carbon atoms as a main monomer, and copolymerizing this with a functional group-containing monomer and, if necessary, other modifying monomers copolymerizable with these by a conventional method. The weight average molecular weight of the functional group-containing (meth)acrylic polymer is usually about 200,000 to 2,000,000. In addition, in the present specification, the weight average molecular weight can be usually determined by the GPC method, and can be determined by a polystyrene standard, for example, using THF as an eluent and HSPgel HR MB-M 6.0 × 150 mm (manufactured by Waters) as a column at 40°C.

Examples of the functional group-containing monomer include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an epoxy group-containing monomer, an isocyanate group-containing monomer, an amino group-containing monomer, and the like. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, and the like. Examples of the hydroxyl group-containing monomer include hydroxyethyl acrylate, hydroxyethyl methacrylate, and the like. Examples of the epoxy group-containing monomer include glycidyl acrylate, glycidyl methacrylate, and the like. Examples of the isocyanate group-containing monomer include ethyl acrylate, ethyl methacrylate, and the like. Examples of the amino group-containing monomer include aminoethyl acrylate, aminoethyl methacrylate, and the like.

Other copolymerizable modifying monomers include, for example, various monomers used in general (meth)acrylic polymers, such as vinyl acetate, acrylonitrile, and styrene.

As the functional group-containing unsaturated compound to be reacted with the above functional group-containing (meth)acrylic polymer, the same functional group-containing monomer as the functional group-containing monomer described above can be used depending on the functional group of the above functional group-containing (meth)acrylic polymer. For example, if the functional group of the above functional group-containing (meth)acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used. If the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. If the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used. If the functional group is an amino group, an epoxy group-containing monomer is used.

The above ultraviolet polymerization initiator may be, for example, one that is activated by irradiating ultraviolet rays having a wavelength of 200 to 410 nm. Examples of such ultraviolet polymerization initiators include acetophenone derivative compounds, benzoin ether compounds, ketal derivative compounds, phosphine oxide derivative compounds, bis(η5-cyclopentadienyl)titanocene derivative compounds, benzophenone, Michler's ketone, chlorothioxanthone, todecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexylphenyl ketone, 2-hydroxymethylphenylpropane, and the like. Examples of the acetophenone derivative compounds include methoxyacetophenone, and the like. Examples of the benzoin ether compounds include benzoin propyl ether, benzoin isobutyl ether, and the like. Examples of the above ketal derivative compounds include benzyl dimethyl ketal, acetophenone diethyl ketal, etc. These ultraviolet polymerization initiators may be used alone, or two or more types may be used in combination.

It is preferable that the above-mentioned ultraviolet-curable pressure-sensitive adhesive layer contains a radically polymerizable multifunctional oligomer or monomer. By containing the above-mentioned ultraviolet-curable pressure-sensitive adhesive layer a radically polymerizable multifunctional oligomer or monomer, ultraviolet-curability is improved.

The above-mentioned multifunctional oligomer or monomer preferably has a weight average molecular weight of 10,000 or less, and more preferably, in order to efficiently form a three-dimensional network of an ultraviolet-curable pressure-sensitive adhesive layer by irradiation with ultraviolet rays, the weight average molecular weight is 5,000 or less and the number of radically polymerizable unsaturated bonds in the molecule is 2 to 20. The above-mentioned weight average molecular weight can be determined using, for example, a GPC measurement method.

The above-mentioned polyfunctional oligomers or monomers include, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, or the same methacrylates mentioned above. In addition, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylates, or the same methacrylates mentioned above, or the like. These polyfunctional oligomers or monomers may be used alone, or two or more may be used in combination.

The above ultraviolet-curable pressure-sensitive adhesive layer may contain a crosslinking agent for the purpose of increasing the cohesiveness of the ultraviolet-curable adhesive.

Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, a metal chelate-based crosslinking agent, etc. Among them, an isocyanate-based crosslinking agent is preferable because it increases the cohesive strength of the ultraviolet-curable adhesive.

It is preferable that the crosslinking agent is contained in the adhesive layer in an amount of 0.1 to 20 wt%.

By containing the crosslinking agent in the above range, the ultraviolet-curable adhesive can be appropriately crosslinked and the cohesiveness of the ultraviolet-curable adhesive can be further increased while maintaining high adhesiveness. From the viewpoint of further increasing the cohesiveness of the ultraviolet-curable adhesive while maintaining high adhesiveness, the more preferable lower limit of the content of the crosslinking agent is 0.5 wt%, a more preferable lower limit is 1.0 wt%, a more preferable upper limit is 15 wt%, and a more preferable upper limit is 10 wt%.

It is preferable that the above ultraviolet-curable adhesive layer contains a silicone or fluorine compound.

Since the above-described ultraviolet-curable pressure-sensitive adhesive layer contains a silicone or fluorine compound, the silicone or fluorine compound bleeds out at the interface between the ultraviolet-curable pressure-sensitive adhesive layer and the adherend, so that the adhesive tape can be easily peeled off without leaving any residue after the processing is completed. Examples of the silicone or fluorine compound include silicone diacrylate, a polymer having a fluoroalkyl group (for example, a (meth)acrylic copolymer having a structural unit derived from fluoroacrylate), and the like.

It is preferable that the above silicone or fluorine compound has a functional group capable of crosslinking with the polymerizable polymer.

Since the above silicone or fluorine compound has a functional group capable of crosslinking with the polymerizable polymer, the silicone or fluorine compound can chemically react with the polymerizable polymer by a crosslinking agent or ultraviolet irradiation and bond with the polymerizable polymer. As a result, contamination due to attachment of the silicone or fluorine compound to the adherend is suppressed.

The functional group crosslinkable with the polymerizable polymer is appropriately selected depending on the functional group contained in the polymerizable polymer, and examples thereof include a carboxyl group, a radically polymerizable unsaturated bond, a hydroxyl group, an amide group, an isocyanate group, an epoxy group, and the like. Among these, a radically polymerizable unsaturated bond is preferable. Since the silicone or fluorine compound has a radically polymerizable unsaturated bond as the functional group crosslinkable with the polymerizable polymer, the silicone or fluorine compound chemically reacts with the polymerizable polymer by ultraviolet irradiation and is introduced into the polymerizable polymer, so that contamination due to attachment of the silicone or fluorine compound to the adherend is more suppressed.

The crosslinkable functionality in the above silicone or fluorine compound is, for example, 2 to 6 valence, preferably 2 to 4 valence, more preferably 2.

The functional group capable of crosslinking with the polymerizable polymer is appropriately determined by the functional group contained in the polymerizable polymer. For example, when the polymerizable polymer is a (meth)acrylic acid alkyl ester having a radically polymerizable unsaturated bond in the molecule, it is preferable to select an unsaturated bond and a crosslinkable functional group.

The above unsaturated bond and crosslinkable functional group are functional groups having unsaturated double bonds, and specifically, for example, a silicone or fluorine compound containing a vinyl group, a (meth)acrylic group, an allyl group, a maleimide group, etc. are selected.

The content of the silicone or fluorine compound in the above ultraviolet-curable pressure-sensitive adhesive layer is preferably a lower limit of 2 wt%, a more preferably lower limit of 5 wt%, a further preferably lower limit of 10 wt%, a preferably upper limit of 40 wt%, a more preferably upper limit of 35 wt%, and a further preferably upper limit of 30 wt%.

By having the content of the above silicone or fluorine compound within the above range, the amount of outgassing generated from the adhesive tape can be reduced, and an adhesive tape having superior heat resistance and glue residue prevention performance can be obtained.

It is preferable that the above ultraviolet-curable adhesive layer contains urethane acrylate.

Since the above-mentioned ultraviolet-curable adhesive layer contains urethane acrylate, the flexibility of the adhesive tape is improved, making it difficult for the resulting adhesive tape to be torn off.

The content of the urethane acrylate in the above-mentioned ultraviolet-curable pressure-sensitive adhesive layer is preferably an upper limit of 20 wt%, more preferably an upper limit of 15 wt%, and even more preferably an upper limit of 10 wt%. When the content of the urethane acrylate is within the above range, an adhesive tape having better heat resistance and excellent glue residue suppression performance can be obtained. The lower limit of the content of the urethane acrylate is not particularly limited, but is preferably 1 wt% from the viewpoint of making the adhesive tape less likely to be torn off and suppressing glue residue.

It is preferable that the total content of the silicone or fluorine compound and the urethane acrylate in the above ultraviolet-curable pressure-sensitive adhesive layer is 50 wt% or less.

Since the total content of the silicone or fluorine compound and the urethane acrylate is within the above range, the amount of outgas generated by thermal decomposition of these components can be suppressed, thereby improving heat resistance while suppressing unintended peeling due to outgas. From the viewpoint of further suppressing the peeling, a more preferable upper limit of the total content of the silicone or fluorine compound and the urethane acrylate is 40 wt%, and a further preferable upper limit is 25 wt%.

It is preferable that the above ultraviolet-curable adhesive layer contains a filler.

The above ultraviolet-curable pressure-sensitive adhesive layer can improve the heat resistance of the adhesive tape because its elastic modulus is improved by containing filler. Examples of the filler material include silica, alumina, carbon black, calcium, boron, magnesium, zirconia, etc. Among them, silica is preferable because it has improved heat resistance.

The average particle size of the above filler is not particularly limited, but the preferred lower limit is 0.06 ㎛, the more preferred lower limit is 0.07 ㎛, the preferred upper limit is 2 ㎛, and the more preferred upper limit is 1 ㎛. When the average particle size of the filler is within the above range, the dispersibility for the ultraviolet-curable adhesive can be further improved.

The content of the filler in the above ultraviolet-curable pressure-sensitive adhesive layer is preferably a lower limit of 1 wt%, a more preferably lower limit of 3 wt%, a more preferably upper limit of 18 wt%, and a more preferably upper limit of 12 wt%.

Since the content of the above filler is within the above range, an adhesive tape having superior heat resistance can be produced.

It is preferable that the above ultraviolet-curable adhesive layer contains a gas-generating agent that generates gas upon stimulation.

Since the above-mentioned ultraviolet-curable adhesive layer contains a gas-generating agent, a gap is created between the adherend and the adhesive tape by the gas by stimulating it after the process is completed, so that the adhesive tape can be peeled off more easily.

The above gas generator is not particularly limited, but is preferably a gas generator that generates gas by light in that it can be used in a high-temperature treatment process. Among these, carboxylic acid compounds such as phenylacetic acid, diphenylacetic acid, and triphenylacetic acid or salts thereof, or tetrazole compounds such as 1H-tetrazole, 5-phenyl-1H-tetrazole, and 5,5-azobis-1H-tetrazole or salts thereof are preferable in that they have excellent resistance to treatment involving heating. Such gas generators generate gas by irradiating light such as ultraviolet rays, and have high heat resistance that does not decompose even at a high temperature of about 260°C.

The above-described ultraviolet-curable pressure-sensitive adhesive layer may contain a photosensitizer. By containing the photosensitizer, even when the 405 nm ultraviolet transmittance of the above-described base film is low, the ultraviolet-curable pressure-sensitive adhesive layer can be sufficiently cured. In addition, since the photosensitizer has an effect of amplifying stimulation by light to the gas generating agent, gas can be released by irradiating less light. In addition, gas can be released by light in a wider wavelength range.

Examples of the photosensitizer include thioxanthone compounds such as 2,4-diethylthioxanthone, anthracene compounds such as dibutyl anthracene, dipropyl anthracene, etc. In addition, 2,2-dimethoxy-1,2-diphenylethan-1-one, benzophenone, 2,4-dichlorobenzophenone, o-benzoyl benzoate methyl, 4,4'-bis(dimethylamino)benzophenone, 4-benzoyl-4' methyldiphenyl sulfide, etc. can be mentioned. These photosensitizers may be used alone, or two or more types may be used in combination. In addition, since the photosensitizer thermally decomposes at high temperatures to generate outgas and foams the ultraviolet-curable adhesive layer, if used in large quantities, it may cause glue residue or unintended peeling. Therefore, it is preferable to reduce the amount of the photosensitizer used as much as possible.

The above-mentioned ultraviolet-curable adhesive layer may contain known additives such as a plasticizer, resin, surfactant, wax, etc. These additives may be used alone or in combination.

The storage elastic modulus G' of the above-mentioned UV-curable pressure-sensitive adhesive layer before UV irradiation is not particularly limited, but it is preferable that the storage elastic modulus G' at 23°C is 5.0 × 10 ³ Pa or more and 1.0 × 10 ⁵ Pa or less. When the storage elastic modulus G' at 23°C of the UV-curable pressure-sensitive adhesive layer before UV irradiation is within the above range, the adherend can be protected with sufficient adhesive strength. The storage elastic modulus G' at 23°C of the UV-curable pressure-sensitive adhesive layer before UV irradiation can be controlled depending on the type of adhesive constituting the UV-curable pressure-sensitive adhesive layer, the type and amount of the filler, etc.

The storage elastic modulus G' of the above-mentioned UV-curable pressure-sensitive adhesive layer at 23°C before UV irradiation can be obtained by measuring the storage elastic modulus using a viscoelasticity spectrometer (e.g., DVA-200, manufactured by IT Instrumentation and Control Co., Ltd.) under the conditions of constant-rate heating shear mode, a heating rate of 10°C/min, and a frequency of 10 Hz.

The thickness of the above-described ultraviolet-curable pressure-sensitive adhesive layer is not particularly limited, but is preferably a lower limit of 5 μm and an upper limit of 100 μm. When the thickness of the above-described ultraviolet-curable pressure-sensitive adhesive layer is within the above range, the adherend can be protected with sufficient adhesive strength, and also the adhesive residue upon peeling can be suppressed. From the viewpoint of further improving the adhesive strength and further suppressing the adhesive residue upon peeling, the more preferable lower limit of the thickness of the above-described ultraviolet-curable pressure-sensitive adhesive layer is 10 μm, and the more preferable upper limit is 60 μm.

It is preferable that the adhesive tape of the present invention has an adhesive layer on a surface opposite to the surface on which the ultraviolet-curable adhesive layer of the base film is laminated.

Since the adhesive tape of the present invention is a double-sided adhesive tape having an ultraviolet-curable adhesive layer on one side of a base film and an adhesive layer on the other side, a support such as glass and an adherend can be bonded through the double-sided adhesive tape, and therefore a process for manufacturing a semiconductor device using the support can be performed.

The adhesive constituting the above adhesive layer is not particularly limited, and examples thereof include acrylic adhesives, silicone adhesives, and urethane adhesives. Among these, acrylic or silicone adhesives are preferable because they have excellent heat resistance.

In addition, as the adhesive constituting the adhesive layer, the ultraviolet-curable adhesive described above can be used. By using the ultraviolet-curable adhesive, the support can be maintained with sufficient adhesive strength, and when the support is a transparent support, the support can be maintained even when high-temperature processing is performed by curing the adhesive layer made of the ultraviolet-curable adhesive after attachment. In addition, the support can be easily removed after the support becomes unnecessary.

It is preferable that the above adhesive layer contains a gas generating agent that generates gas upon stimulation.

Since the above adhesive layer contains a gas generating agent, the support and the adhesive tape can be easily separated by stimulating the gas to be generated after the process is completed.

The above gas generator may be the same as the gas generator of the above ultraviolet-curable adhesive layer.

The thickness of the above adhesive layer is not particularly limited, but is preferably 5 ㎛ in the lower limit and 30 ㎛ in the upper limit. When the thickness of the above adhesive layer is within the above range, it can be adhered to the support with sufficient adhesive strength. From the viewpoint of further increasing the adhesive strength with the support, the more preferable lower limit of the thickness of the above adhesive layer is 10 ㎛, and the more preferable upper limit is 20 ㎛.

The above adhesive layer may contain known additives such as a photosensitizer, a plasticizer, a resin, a surfactant, a wax, or a fine particle filler. These additives may be used alone or in combination.

The adhesive tape of the present invention may have an anchor layer between the substrate film and the ultraviolet-curable adhesive layer.

If an anchor layer is provided between the above-described base film and the above-described ultraviolet-curable adhesive layer, when the ultraviolet-curable adhesive layer contains a silicone or fluorine compound, the silicone or fluorine compound can be prevented from bleeding out toward the base film side, thereby preventing the ultraviolet-curable adhesive layer from being peeled off from the base film.

Examples of the anchor layer include acrylic adhesives, urethane adhesives, etc. Among them, acrylic adhesives are preferable because of their superior anchoring performance.

The above anchor layer may contain known additives such as inorganic fillers, heat stabilizers, antioxidants, antistatic agents, plasticizers, resins, surfactants, waxes, etc., as needed. These additives may be used alone or in combination.

The thickness of the anchor layer is not particularly limited, but a preferable lower limit is 1 ㎛, and a preferable upper limit is 30 ㎛. When the thickness of the anchor layer is within this range, the anchoring force of the ultraviolet-curable pressure-sensitive adhesive layer and the base film can be further improved. From the viewpoint of further improving the anchoring force of the ultraviolet-curable pressure-sensitive adhesive layer and the base film, a more preferable lower limit of the thickness of the anchor layer is 3 ㎛, and a more preferable upper limit is 10 ㎛.

The method for manufacturing the adhesive tape of the present invention is not particularly limited, and a conventionally known method can be used. For example, the adhesive tape can be manufactured by coating a solution of the above-described ultraviolet-curable adhesive component on a film that has undergone a release treatment, drying the solution to form an ultraviolet-curable adhesive layer, and bonding the same to a base film. In addition, when the adhesive tape of the present invention has the above-described adhesive layer, the adhesive layer can be manufactured by forming the adhesive layer using a solution of an adhesive constituting the above-described adhesive layer in the same manner as the above-described ultraviolet-curable adhesive layer, and bonding the same to a surface of the base film opposite to the surface on which the above-described ultraviolet-curable adhesive layer is bonded.

The use of the adhesive tape of the present invention is not particularly limited, but since it protects an adherend and can be peeled off without leaving any adhesive residue even when used in a harsh environment where high temperatures and pressures are applied, it can be particularly preferably used as a protective tape for protecting wafers, semiconductor chips, etc. in the manufacture of electronic components.

As a method for manufacturing such an electronic component, the following method for manufacturing an electronic component can be given. That is, the method includes, in this order, a substrate attachment step of attaching the adhesive tape of the present invention to a substrate from an ultraviolet-curable adhesive layer, a curing step of curing the ultraviolet-curable adhesive layer by irradiating it with ultraviolet rays, a heat treatment step of treating the substrate at a high temperature of 260° C. or higher, and a peeling step of peeling the substrate from the adhesive tape of the present invention.

In addition, the following method for manufacturing an electronic component may be exemplified, which uses an adhesive tape having an adhesive layer on a surface opposite to the surface on which the ultraviolet-curable adhesive layer of the base film, which is an embodiment of the present invention, is laminated. That is, the method includes, in this order, a substrate attaching step of attaching the adhesive tape to a substrate from the ultraviolet-curable adhesive layer, a support attaching step of attaching a support onto the adhesive layer, a curing step of curing the ultraviolet-curable adhesive layer by irradiating it with ultraviolet rays, a heat treatment step of treating the substrate at a high temperature of 260°C or higher, and a peeling step of peeling the substrate from the adhesive tape. In addition, the method includes, in this order, a substrate attachment process of attaching an adhesive tape to a substrate from an ultraviolet-curable adhesive layer, a curing process of curing the ultraviolet-curable adhesive layer by irradiating it with ultraviolet rays, a support attachment process of attaching a support onto the adhesive layer, a heat treatment process of treating the substrate at a high temperature of 260°C or higher, and a peeling process of peeling the substrate from the adhesive tape.

The above substrate is not particularly limited, and examples thereof include a silicon wafer, a semiconductor wafer, a semiconductor chip, etc.

The support is not particularly limited, and examples thereof include glass, polyimide film, glass epoxy substrate, etc.

The upper temperature limit of the heat treatment process at a high temperature of 260°C or higher is not particularly limited, and is, for example, 400°C, preferably 300°C.

The heat treatment process at a high temperature of 260° C. or higher is not particularly limited, and examples thereof include a substrate manufacturing process, a chip mounting process, a thermal compression bonding process, a reflow process, etc. More specifically, examples thereof include a thermal compression bonding process or a reflow process in which an adhesive tape is heated to 260° C. or higher for several tens of seconds to 1 minute.

According to the present invention, it is possible to provide an adhesive tape that protects an adherend and can be peeled off without leaving any residue even when used in a process involving high-temperature treatment up to 260°C.

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

(Example 1)

(Manufacture of UV-curable adhesive A)

A reactor equipped with a thermometer, a stirrer, and a condenser was prepared, and 94 parts by weight of 2-ethylhexylacrylate as a (meth)acrylic acid alkyl ester, 6 parts by weight of hydroxyethyl methacrylate as a functional group-containing monomer, 0.01 part by weight of lauryl mercaptan, and 80 parts by weight of ethyl acetate were added into the reactor, and then the reactor was heated to initiate reflux. Subsequently, 0.01 part by weight of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane as a polymerization initiator was added into the reactor, and polymerization was initiated under reflux. Next, 0.01 part by weight of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added 1 hour and 2 hours after the initiation of polymerization, and further, 0.05 part by weight of t-hexylperoxypivalate was added 4 hours after the initiation of polymerization to continue the polymerization reaction. Then, 8 hours after the initiation of polymerization, an ethyl acetate solution of a functional group-containing (meth)acrylic polymer having a solid content of 55 wt% and a weight average molecular weight of 600,000 was obtained.

To 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained functional group-containing (meth)acrylic polymer, 3.5 parts by weight of 2-isocyanatoethyl methacrylate as a functional group-containing unsaturated compound was added and reacted to obtain a polymerizable polymer (acrylic polymer) A. Thereafter, to 100 parts by weight of the resin solid content of the ethyl acetate solution of the obtained acrylic polymer A, 20 parts by weight of a release agent (silicone), 3 parts by weight of a filler, 10 parts by weight of a urethane acrylate, 0.2 parts by weight of a crosslinking agent, and 1 part by weight of a photopolymerization initiator were mixed, to obtain an ethyl acetate solution of an ultraviolet-curable adhesive A. In addition, the release agent (silicone), filler, urethane acrylate, crosslinking agent, and photopolymerization initiator were used as follows.

Release agent (silicon): Silicone diacrylate, EBECRYL 350, manufactured by Daicel Allnex, weight average molecular weight 1000

Filler: Silica filler, Leorosil MT-10, manufactured by Tokuyama

Urethane acrylate: UN-5500, manufactured by Negami Industries, Ltd.

Crosslinking agent: Isocyanate crosslinking agent, Coronate L, manufactured by Nippon Urethane Industry Co., Ltd.

Photopolymerization initiator: Esacure One, manufactured by Siberhegner, Japan

(Manufacture of adhesive A for adhesive layer)

In the production of an ultraviolet-curable adhesive A, 10 parts by weight of a release agent (silicone), 12 parts by weight of a filler, 20 parts by weight of a urethane acrylate, 1.2 parts by weight of a crosslinking agent, 1 part by weight of a photopolymerization initiator, and 10 parts by weight of a gas generator were mixed with 100 parts by weight of a resin solid content of an ethyl acetate solution of an acrylic polymer A, to obtain an ethyl acetate solution of an adhesive A for an adhesive layer. In addition, the release agent (silicone), the filler, the urethane acrylate, the crosslinking agent, and the photopolymerization initiator were the same as those used in the production of the ultraviolet-curable adhesive. The gas generator used was a salt of a bistetrazole compound represented by the following formula (A).

(Manufacture of adhesive for anchor layer)

For 100 parts by weight of the resin solid content of an ethyl acetate solution of an acrylic polymer, 12 parts by weight of a filler and 5 parts by weight of a crosslinking agent were mixed to obtain an ethyl acetate solution of an adhesive for an anchor layer. In addition, the acrylic polymer, filler, and crosslinking agent used were as follows.

Acrylic polymer: SK Dyne 1604N, manufactured by Soken Chemical Co., Ltd.

Filler: Silica filler, Leorosil MT-10, manufactured by Tokuyama

Crosslinking agent: Isocyanate crosslinking agent, Coronate L, manufactured by Nippon Urethane Industry Co., Ltd.

(Manufacture of adhesive tape)

An ethyl acetate solution of the obtained ultraviolet-curable adhesive A was applied onto the release-treated surface of a polyethylene terephthalate (PET) film having a thickness of 50 ㎛, so that the thickness of the adhesive layer became 130 ㎛ after drying, and then dried at 100° C. for 10 minutes to form an ultraviolet-curable adhesive layer.

Meanwhile, an ethyl acetate solution of the adhesive A for the adhesive layer was applied onto the release-treated surface of another 50 ㎛-thick PET film so that the thickness of the adhesive layer became 20 ㎛ after drying, and then dried at 110°C for 5 minutes to form an adhesive layer.

An ethyl acetate solution of the obtained anchor layer adhesive was applied onto the release-treated surface of a PET film having another thickness of 50 ㎛ so that the thickness of the adhesive layer became 10 ㎛ after drying, and then dried at 110° C. for 5 minutes to form an anchor layer.

Next, a film (nylon 9T film) made of nylon 9T (Uniamid, manufactured by Unitica) having a thickness of 25 ㎛ and subjected to corona treatment on both sides was prepared as a base film, an anchor layer formed on one side of the nylon 9T film was laminated, and the PET film was peeled off to form an anchor layer on the base film. Thereafter, the obtained ultraviolet-curable adhesive layer was bonded to the side of the nylon 9T film on which the anchor layer was formed, and the obtained adhesive layer was bonded to the side of the nylon 9T film opposite to the side on which the anchor layer was formed, to obtain an adhesive tape having a structure of ultraviolet-curable adhesive layer/anchor layer/base film/adhesive layer.

(Measurement of UV transmittance of substrate film)

The ultraviolet transmittance of the substrate film at 405 nm was measured using a spectrophotometer (U-3900, manufactured by Hitachi, Ltd.).

(Measurement of Ef (270))

A measurement sample was obtained by punching out a substrate film with dimensions of 5 × 35 mm using a punching blade so that the long side was the same as the flow direction during the manufacture of the substrate film. The obtained measurement sample was immersed in liquid nitrogen and cooled to -50°C, and then the tensile modulus was measured using a viscoelastic spectrometer (DVA-200, manufactured by IT Instrumentation and Control Co., Ltd.) under the conditions of constant temperature-rise tensile mode, a heating rate of 10°C/min, and a frequency of 10 Hz, to measure the tensile modulus of the substrate film at 270°C.

(Measurement of storage modulus G' before UV irradiation)

For the UV-curable pressure-sensitive adhesive layer, the storage modulus was measured using a viscoelastic spectrometer (DVA-200, manufactured by IT Instrumentation and Control Co., Ltd.) under the conditions of constant-rate heating shear mode, heating rate of 10°C/min, and frequency of 10 Hz, and the storage modulus G' of the UV-curable pressure-sensitive adhesive layer at 23°C before UV irradiation was obtained.

(Measurement of gel fraction after UV irradiation)

Using a high-pressure mercury ultraviolet irradiator, 405 nm ultraviolet ray was irradiated from the base film side of the obtained adhesive tape so that the accumulated intensity with respect to the surface of the adhesive tape became 3000 mJ/cm2 to crosslink and harden the ultraviolet-curable adhesive layer. Next, only 0.1 g of the cured ultraviolet-curable adhesive layer was removed, immersed in 50 ml of ethyl acetate, and shaken for 24 hours under the conditions of a temperature of 23 degrees and 120 rpm using a shaker (hereinafter, the removed ultraviolet-curable adhesive layer is referred to as an adhesive composition). After shaking, ethyl acetate and the adhesive composition that had absorbed ethyl acetate and swelled were separated using a metal mesh (measurement interval #200 mesh). The separated adhesive composition was dried under the condition of 110 degrees Celsius for 1 hour. The weight of the adhesive composition including the metal mesh after drying was measured, and the gel fraction after ultraviolet irradiation was calculated using the following formula.

Gel fraction (%) = 100 × (W ₁ -W ₂ )/W ₀

(W ₀ : initial adhesive composition weight, W ₁ : adhesive composition weight including metal mesh after drying, W ₂ : initial weight of metal mesh)

(Measurement of Et (270))

Using a high-pressure mercury ultraviolet irradiator, 405 nm ultraviolet ray was irradiated from the base film side of the obtained adhesive tape so that the accumulated intensity with respect to the surface of the adhesive tape became 3000 mJ/cm2 to crosslink and harden the ultraviolet-curable adhesive layer. Then, a punching blade was used to punch out pieces so that the long side was the same as the flow direction during the production of the adhesive tape, thereby producing a 5 mm × 35 mm test piece. The obtained test piece was immersed in liquid nitrogen and cooled to -50 °C, and thereafter, using a viscoelasticity spectrometer (DVA-200, manufactured by IT Instrumentation and Control Co., Ltd.), the temperature was increased to 300 °C under the conditions of constant temperature-rise tensile mode, a heating rate of 10 °C/min, and a frequency of 10 Hz, and the tensile modulus was measured. The value of the tensile modulus (E') at the temperature X °C at this time was taken as Et (X). That is, the value of the tensile elastic modulus (E') at a temperature of 270 ℃ was set to Et (270).

(Production of Et (270)/Et (200))

For the obtained adhesive tape, the tensile modulus (Et (200)) of the adhesive tape at 200°C was measured in the same manner as for Et (270). From the results of the obtained Et (270) and Et (200), Et (270)/Et (200) was calculated.

(Measurement of weight loss rate)

Using a high-pressure mercury ultraviolet irradiator, 405 nm ultraviolet ray was irradiated from the base film side of the obtained adhesive tape so that the accumulated intensity with respect to the surface of the adhesive tape became 3000 mJ/cm2 to crosslink and harden the ultraviolet-curable adhesive layer. Next, the adhesive tape was stamped into a φ5 mm circle to obtain a measurement sample. The weight of the obtained measurement sample was measured, and the weight loss when the temperature was increased from 25 ℃ to 280 ℃ at a heating rate of 5 ℃/min and then held for 10 minutes was measured using a differential thermal gravimetric measurement device (TG-DTA; STA7200, manufactured by Hitachi High-Tech Science Co., Ltd.). The weight loss rate was calculated from the weight before and after heating.

(Examples 2 to 10, Comparative Examples 1 to 4)

Except that the material and thickness of the substrate film and the composition of the ultraviolet-curable pressure-sensitive adhesive layer were changed as shown in Table 1, an adhesive tape was obtained and each measurement was performed in the same manner as in Example 1. The details of each material are shown below. In addition, in Example 5, the ultraviolet-curable pressure-sensitive adhesive B shown below was used.

(1) Material of the substrate film

Xpeak: Aromatic polyetheretherketone, manufactured by Kurabo Corporation

Uprex: Copolymer of biphenyltetracarboxylic acid dianhydride and p-phenylenediamine, manufactured by Ubecosan Co., Ltd.

Torsena: Special polyester, manufactured by Kurabo

Kapton: Copolymer of anhydrous pyromet acid and diaminodiphenyl ether, manufactured by Toray and DuPont.

(2) UV-curable adhesive B

(Manufacture of UV-curable adhesive B)

A reactor equipped with a thermometer, a stirrer, and a condenser was prepared, and 94 parts by weight of 2-ethylhexylacrylate as a (meth)acrylic acid alkyl ester, 6 parts by weight of hydroxyethyl methacrylate as a functional group-containing monomer, 0.01 parts by weight of lauryl mercaptan, and 80 parts by weight of ethyl acetate were added into the reactor, and then the reactor was heated to initiate reflux. Subsequently, 0.01 parts by weight of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane as a polymerization initiator was added into the reactor to initiate polymerization under reflux. Next, 0.01 part by weight of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added 1 hour and 2 hours after the initiation of polymerization, and further, 0.05 part by weight of t-hexylperoxypivalate was added 4 hours after the initiation of polymerization to continue the polymerization reaction. Then, 8 hours after the initiation of polymerization, an ethyl acetate solution of a functional group-containing (meth)acrylic polymer having a solid content of 55 wt% and a weight average molecular weight of 600,000 was obtained.

To 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained functional group-containing (meth)acrylic polymer, 1.0 parts by weight of 2-isocyanatoethyl methacrylate as a functional group-containing unsaturated compound was added and reacted to obtain a polymerizable polymer (acrylic polymer) B. Thereafter, to 100 parts by weight of the resin solid content of the ethyl acetate solution of the obtained acrylic polymer B, 20 parts by weight of a release agent (silicone), 3 parts by weight of a filler, 10 parts by weight of a urethane acrylate, 0.2 parts by weight of a crosslinking agent, and 1 part by weight of a photopolymerization initiator were mixed to obtain an ethyl acetate solution of an ultraviolet-curable adhesive B. In addition, the release agent (silicone), filler, urethane acrylate, crosslinking agent, and photopolymerization initiator were of the same type as those used in the ultraviolet-curable adhesive A.

(3) Other

Photosensitive agent: KAYACURE DETX-S, manufactured by Nippon Chemical Co., Ltd.

＜Evaluation＞

The adhesive tapes obtained in the examples and comparative examples were evaluated by the following method. The results are shown in Table 1.

(Evaluation of heat resistance)

The UV-curable adhesive layer side of an adhesive tape cut into a circle with a diameter of 20 cm was attached to a silicon wafer with a diameter of 20 cm and a thickness of approximately 750 ㎛. Next, the adhesive layer side of the adhesive tape was attached to a glass wafer (Tempax, manufactured by SCHOTT) with a diameter of 20 cm and a thickness of 0.6 mm. After attachment, ultraviolet light having a wavelength of 405 nm was irradiated from the glass wafer surface side with wavelengths of 365 nm or less cut off by a filter so that the accumulated intensity with respect to the UV-curable adhesive layer became 3000 mJ/cm2, thereby crosslinking and curing the UV-curable adhesive layer and the adhesive layer. The resulting silicon wafer/adhesive tape/glass wafer laminate was placed with the silicon wafer side down on a hot plate (NINOS ND-3H, manufactured by AZONE) set to 280°C, and the time until peeling of the adhesive tape occurred was measured.

(Evaluation of peelability)

The ultraviolet-curable adhesive layer side of the adhesive tape and a silicon wafer having a diameter of 20 cm and a thickness of approximately 750 ㎛ were bonded together, and further, the adhesive layer side was bonded to a glass wafer having a diameter of 20 cm and a thickness of 0.6 mm, to obtain a laminate. Next, using a high-pressure mercury ultraviolet irradiator, 405 nm ultraviolet ray was irradiated from the glass wafer side for 30 seconds at an illuminance adjusted so that the irradiation intensity to the adhesive tape surface of the adhesive tape was 100 mW/cm2, so as to crosslink and harden the ultraviolet-curable adhesive layer and the adhesive layer. Thereafter, the laminate was placed with the silicon wafer side down on a hot plate set to 280°C, heat treated for 10 minutes, and then allowed to cool.

After cooling, the adhesive tape was peeled from the silicon wafer. The peelability was evaluated by marking “○” when the adhesive tape could be easily peeled off during peeling, and “×” when it could not be peeled off. In addition, when the adhesive tape was peeled off within 10 minutes, the heat treatment was stopped at the peeled stage, and the peelability after cooling was evaluated.

(Evaluation of full residual)

In evaluating the peelability, the silicon wafer after peeling of the adhesive tape was observed with an optical microscope, and the area where the adhesive residue was less than 5% of the entire silicon wafer was evaluated as “◎”, 5% or more but less than 20% was evaluated as “○”, 20% or more but less than 50% was evaluated as “△”, and 50% or more was evaluated as “×”.

(Evaluation of peelability during thermal compression)

The UV-curable adhesive layer side of the adhesive tape cut into a circle having a diameter of 20 cm was attached to a surface on which bumps were formed, a silicon wafer with a bump attachment having a diameter of 20 cm and a thickness of 50 ㎛ (bump diameter φ = 20 ㎛, distance between bumps 30 ㎛, bump height 45 ㎛). Next, the adhesive layer side of the adhesive tape was attached to a glass wafer (Tempax, manufactured by SCHOTT) having a diameter of 20 cm and a thickness of 0.6 mm. After attachment, ultraviolet light having a wavelength of 405 nm was irradiated from the glass wafer surface side with wavelengths of 365 nm or less cut off by a filter so that the accumulated intensity with respect to the UV-curable adhesive layer became 3000 mJ/cm2, thereby crosslinking and curing the UV-curable adhesive layer and the adhesive layer. The obtained silicon wafer/adhesive tape/glass wafer laminate was placed in an oven set to 200°C with the glass wafer side facing down for 1 hour and then heat-treated.

After heat treatment, a 50 ㎛ thick single crystal silicon foil wafer chip was laminated on the silicon wafer of the laminated body which had returned to room temperature using a flip chip bonder (FC6000, manufactured by Shibaura Mechatronics Co., Ltd.). Specifically, the laminated body was adsorbed on a SUS stage set to 80 ℃ with the silicon wafer side facing upward, and the single crystal silicon foil wafer chip (9.8 mm × 9.8 mm, 50 ㎛ thick, surface roughness less than 0.1 ㎛, with a bonding film having a thickness of 25 ㎛ attached) was laminated using a ceramic tool having a head size of 10 mm × 10 mm. The head temperature during lamination was 280 ℃, the pressure was 300 N, and the lamination time was 90 seconds.

After laminating the single crystal silicon wafer chips, the adhesive tape was peeled off from the silicon wafer. When the adhesive tape could be easily peeled off during peeling, it was marked as “○”, and when it could not be peeled off, it was marked as “×”, and the peelability during thermal compression was evaluated.

(Evaluation of glue residue during heat pressing)

In evaluating the peelability during thermal compression, the silicon wafer after peeling of the adhesive tape was observed with an optical microscope. When the percentage of bumps with glue residue among those existing in a 500 ㎛ square area was 5% or less, it was marked as "◎", when it was more than 5% but less than 20%, it was marked as "○", when it was more than 20% but less than 50%, it was marked as "△", and when it was more than 50%, it was marked as "×", and the percentage was evaluated as "◎".

Industrial applicability

According to the present invention, it is possible to provide an adhesive tape that protects an adherend even when used in a process involving high-temperature treatment up to 260°C, and further, can be peeled off without leaving any residue.

Claims (11)

An adhesive tape having a substrate film and an ultraviolet-curable adhesive layer laminated on one side of the substrate film,
The above ultraviolet-curable adhesive layer contains a silicone or fluorine compound,
The gel fraction of the UV-curable adhesive layer is 90% or more after irradiating the surface of the substrate film side of the adhesive tape with 405 nm UV rays at 3000 mJ/cm2,
An adhesive tape, wherein when the tensile elastic modulus of the adhesive tape at X ℃ is represented by Et (X) after irradiating the surface of the substrate film side of the adhesive tape with 3000 mJ/cm2 of 405 nm ultraviolet rays, the value of Et (270) is 1.0 × 10 ⁷ Pa or more. In paragraph 1,
An adhesive tape having an ultraviolet ray transmittance of 405 nm of the above-described film of 1% or more. In claim 1 or 2,
An adhesive tape having an Et (270)/Et (200) value of 0.1 or greater. In claim 1 or 2,
An adhesive tape, wherein the tensile modulus of the above-mentioned film at X ℃ is Ef (X), and the value of Ef (270) is 5.0 × 10 ⁷ Pa or more. In claim 1 or 2,
An adhesive tape, wherein the weight reduction rate when the surface of the substrate film side of the adhesive tape is irradiated with 3000 mJ/cm2 of 405 nm ultraviolet rays, the temperature is increased from 25°C to 280°C at a rate of 5°C/min, and the tape is held for 10 minutes after the temperature increase is increased is 5% or less. In claim 1 or 2,
The above-mentioned adhesive tape comprises a resin having at least one selected from the group consisting of amides, imides, ethers and ketones in the main chain skeleton of repeating units. In claim 1 or 2,
The above-mentioned film is an adhesive tape containing a polyamide resin having a long-chain alkyl group or aromatic group having 4 to 12 carbon atoms in the main chain skeleton of the repeating unit. In claim 1 or 2,
The above ultraviolet-curable adhesive layer contains a polymerizable polymer of (meth)acrylic acid alkyl ester type having a radical polymerizable unsaturated bond in the molecule and a polymerization initiator,
An adhesive tape wherein the silicone or fluorine compound has a functional group capable of crosslinking with the polymerizable polymer. In claim 1 or 2,
An adhesive tape having an adhesive layer on a surface opposite to the surface on which the ultraviolet-curable adhesive layer of the above-mentioned substrate film is laminated. In claim 1 or 2,
Adhesive tape used to manufacture electronic components. In claim 1 or 2,
An adhesive tape wherein the above ultraviolet-curable adhesive layer additionally contains a filler.