Adhesive film and method for manufacturing electronic component

Abstract

To provide: an adhesive film having excellent heat resistance and capable of preventing peeling during a high-temperature processing step; and a method for manufacturing an electronic component using the adhesive film.SOLUTION: An adhesive film comprises an adhesive layer and a base material. In a thermomechanical analysis in which the adhesive film is held at 25°C for 10 minutes and then heated from 25°C to 350°C at a heating rate of 10°C / min while maintaining zero change in the length of the adhesive film and detecting the load as thermal shrinkage stress, a temperature at which a maximum value of the thermal shrinkage stress of the adhesive film appears is 260°C or higher, and the glass transition temperature of the adhesive layer is 0°C or higher.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an adhesive film. The present invention also relates to a method for manufacturing an electronic component using the adhesive film.

Background Art

[0002] When processing electronic components such as semiconductors, in order to facilitate the handling of the electronic components and prevent them from being damaged, the electronic components are fixed to a support plate via a temporary fixing material made of an adhesive resin composition, or an adhesive film having an adhesive layer is attached to the electronic components for protection. For example, when a thick film wafer cut out from a high-purity silicon single crystal or the like is ground to a predetermined thickness to obtain a thin film wafer, the thick film wafer is adhered to a support plate via an adhesive resin composition.

[0003] Thus, for the adhesive resin composition and the adhesive film used for electronic components, it is required to have a high adhesiveness capable of firmly fixing the electronic components during the processing step and being peelable without damaging the electronic components after the step is completed (hereinafter, also referred to as "high adhesion and easy peelability"). As a means for realizing high adhesion and easy peelability, for example, Patent Document 1 discloses an adhesive sheet using an adhesive in which a polyfunctional monomer or oligomer having a radiation-polymerizable functional group is bonded to the side chain or main chain of a polymer. By utilizing the fact that the polymer is cured by ultraviolet irradiation due to having a radiation-polymerizable functional group, the adhesive force is reduced by irradiating ultraviolet rays during peeling, and peeling can be performed without adhesive residue.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, in order to cope with the high integration of semiconductors, a TBDB (Temporary bonding / de-bonding) process for manufacturing semiconductors by supporting a thin wafer with a support and a temporary fixing material such as an adhesive film has been adopted. The temporary fixing material used in the TBDB process needs to be capable of being re-peeled after a high-temperature processing step of heating in a state where the support and the wafer are bonded together.

[0006] In recent years, in the high-temperature processing step, heating at a high temperature for a long time has been required. However, during the high-temperature processing step of heating at a high temperature for a long time, the temporary fixing material may shrink thermally, causing the bonded wafer to warp and the temporary fixing material to peel off. Such problems often occur particularly in adhesive films having a base material due to the thermal shrinkage of the base material.

[0007] An object of the present invention is to provide an adhesive film having excellent heat resistance and capable of preventing peeling during a high-temperature processing step. Another object of the present invention is to provide a method for manufacturing an electronic component using the adhesive film.

Means for Solving the Problems

[0008] The present disclosure 1 is an adhesive film having an adhesive layer and a base material, and after holding the adhesive film at 25°C for 10 minutes, while raising the temperature from 25°C to 350°C at a rate of 10°C / min, in a thermomechanical analysis for detecting the load when the change amount of the length of the adhesive film is maintained at 0 as the thermal shrinkage stress, the temperature at which the maximum value of the thermal shrinkage stress of the adhesive film is exhibited is 260°C or higher, and the glass transition temperature of the adhesive layer is 0°C or higher. The present disclosure 2 is the adhesive film of the present disclosure 1, wherein the adhesive layer contains a compound having an imide bond. The present disclosure 3 is the adhesive film of the present disclosure 1 or 2, wherein the adhesive layer contains a polymerization initiator. In the present disclosure 4, the adhesive layer is the adhesive film of the present disclosure 1, 2, or 3 containing an ultraviolet absorber. In the present disclosure 5, the base material is the adhesive film of the present disclosure 1, 2, 3, or 4 containing a resin having a repeating unit containing at least one selected from the group consisting of an ether bond, a ketone group, and an imide bond in the main chain skeleton. In the present disclosure 6, the base material is the adhesive film of the present disclosure 1, 2, 3, 4, or 5 that does not contain fine particles. In the present disclosure 7, the thickness of the base material is the adhesive film of the present disclosure 1, 2, 3, 4, 5, or 6 that is 5 μm or more and 100 μm or less. In the present disclosure 8, the ratio of the thickness of the base material is the adhesive film of the present disclosure 1, 2, 3, 4, 5, 6, or 7 that is 5% or more and 80% or less with respect to the thickness of the entire adhesive film. In the present disclosure 9, the adhesive film is the adhesive film of the present disclosure 1, 2, 3, 4, 5, 6, 7, or 8 having a 5% weight loss temperature of 350 °C or higher. In the present disclosure 10, the adhesive film is the adhesive film of the present disclosure 1, 2, 3, 4, 5, 6, 7, 8, or 9 having a haze greater than 3%. In the present disclosure 11, it is the adhesive film of the present disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 used for the manufacture of electronic components. In the present disclosure 12, it is a method for manufacturing an electronic component using the adhesive film of the present disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11. The present invention will be described in detail below.

[0009] The inventors of the present invention considered adjusting the temperature showing the maximum value of the thermal shrinkage stress measured by thermomechanical analysis and the glass transition temperature of the adhesive layer to a specific range using an adhesive film having an adhesive layer and a base material. As a result, they found that an adhesive film excellent in heat resistance and capable of preventing peeling during a high-temperature processing step could be obtained, and thus completed the present invention.

[0010] The adhesive film of the present invention has an adhesive layer. The above-mentioned adhesive layer preferably contains a compound having an imide bond. The compound having an imide bond preferably includes a resin having an imide skeleton as a repeating unit in the main chain. The resin having an imide skeleton as a repeating unit in the main chain is extremely excellent in heat resistance due to having an imide skeleton, and it is difficult for the main chain to decompose even when a high-temperature processing step of 300 °C or higher is performed. Therefore, by containing a compound having an imide bond including a resin having an imide skeleton as a repeating unit in the main chain, the obtained adhesive film becomes more excellent in heat resistance, and peeling during the high-temperature processing step can be further suppressed. In addition, it is possible to prevent the occurrence of enhanced adhesion to the adherend or the occurrence of glue residue during peeling from the adherend.

[0011] The resin having an imide skeleton as a repeating unit in the main chain preferably has a structural unit represented by the following formula (1).

[0012]

Chemical formula

[0013] In the above formula (1), P 1 is preferably an aromatic group having 5 to 50 carbon atoms. When P 1 is an aromatic group having 5 to 50 carbon atoms, the obtained adhesive film becomes more excellent in heat resistance. That is, peeling during the high-temperature processing step can be further suppressed, and it is possible to further prevent the occurrence of enhanced adhesion to the adherend or the occurrence of glue residue during peeling from the adherend.

[0014] In the above formula (1), Q 1 is preferably a substituted or unsubstituted linear, branched or cyclic aliphatic group having 2 to 100 carbon atoms. The above Q 1By being a linear, branched or cyclic aliphatic group having 2 to 100 carbon atoms, which may be substituted or unsubstituted, the resulting adhesive film becomes excellent in light transmittance. Further, the resulting adhesive film becomes excellent in flexibility, can exhibit high followability with respect to an adherend having unevenness, and can be more easily peeled off at the time of peeling. Further, the above Q 1 is preferably an aliphatic group derived from a diamine compound. Among them, from the viewpoints of light transmittance, flexibility, and compatibility with a solvent or other components of the resin having the above imide skeleton as a repeating unit of the main chain, the above Q 1 is preferably an aliphatic group derived from a dimer diamine. The above dimer diamine is a diamine compound obtained by reducing and aminating cyclic and acyclic dimer acids obtained as dimers of unsaturated fatty acids, and examples thereof include linear, monocyclic, polycyclic and the like dimer diamines. The above dimer diamine may contain a carbon-carbon double bond or may be a hydrogenated product to which hydrogen is added.

[0015] As the aliphatic group derived from the above dimer diamine, for example, at least one group selected from the group consisting of a group represented by the following formula (2-1), a group represented by the following formula (2-2), a group represented by the following formula (2-3), and a group represented by the following formula (2-4) is preferable. Among them, the group represented by the following formula (2-2) is more preferable.

[0016]

Chemical formula

[0017] In formulas (2-1) to (2-4), R 1 ~R 16 each independently represents a linear or branched hydrocarbon group, and * represents a bond. The bond * is bonded to N in the above formula (1).

[0018] In the above formulas (2-1) to (2-4), R 1 ~R 16The hydrocarbon group represented by may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Among them, R 1 and R 2 , R 3 and R 4 , R 5 and R 6 , R 7 and R 8 , R 9 and R 10 , R 11 and R 12 , R 13 and R 14 , and, R 15 and R 16 preferably have a total carbon number of 7 or more and 50 or less. By having the total carbon number within the above range, the resulting adhesive film becomes excellent in light transmittance, flexibility, and compatibility with solvents and other components of the resin having the imide skeleton as the repeating unit of the main chain. The total carbon number is more preferably 9 or more, still more preferably 12 or more, and even more preferably 14 or more. The total carbon number is more preferably 35 or less, still more preferably 25 or less, and even more preferably 18 or less.

[0019] In the group represented by the above formula (2-1), the group represented by the above formula (2-2), the group represented by the above formula (2-3), and the group represented by the above formula (2-4), the optical isomerism is not particularly limited, and any optical isomer is included.

[0020] The resin having the imide skeleton as the repeating unit of the main chain preferably includes a resin having no maleimide group and having the imide skeleton as the repeating unit of the main chain, and more preferably includes a resin having no polymerizable functional group having a carbon-carbon double bond and having the imide skeleton as the repeating unit of the main chain.

[0021] The resin that does not have the above-mentioned maleimide group and has an imide skeleton as a repeating unit in the main chain preferably has a weight average molecular weight of 20,000 or more and 2,000,000 or less. When the weight average molecular weight of the resin that does not have the above-mentioned maleimide group and has an imide skeleton as a repeating unit in the main chain is 20,000 or more, the resulting adhesive film becomes more excellent in heat resistance. That is, peeling during the high-temperature processing step can be further suppressed, and it is possible to further prevent the occurrence of enhanced adhesion to the adherend or the occurrence of glue residue during peeling from the adherend. When the weight average molecular weight of the resin that does not have the above-mentioned maleimide group and has an imide skeleton as a repeating unit in the main chain is 2,000,000 or less, the resin that does not have the above-mentioned maleimide group and has an imide skeleton as a repeating unit in the main chain becomes more excellent in compatibility with solvents and other components. A more preferable lower limit of the weight average molecular weight of the resin that does not have the above-mentioned maleimide group and has an imide skeleton as a repeating unit in the main chain is 40,000, a more preferable upper limit is 600,000, a further preferable lower limit is 50,000, and a further preferable upper limit is 300,000. In addition, in this specification, the above-mentioned weight average molecular weight is measured as a polystyrene-equivalent molecular weight by gel permeation chromatography (GPC) method. Specifically, for example, it can be measured under the conditions of a mobile phase of THF, a flow rate of 1.0 mL / min, a column temperature of 40 °C, a sample concentration of 0.2 mass%, and an RI·PDA detector using an APC system (manufactured by Waters). As the above-mentioned column, HR-MB-M 6.0×150 mm (manufactured by Waters) etc. can be used.

[0022] Specific examples of the resin that does not have the above-mentioned maleimide group and has an imide skeleton as a repeating unit in the main chain include resins having a structural unit represented by the above formula (1) and having a functional group without maleimide groups at both ends.

[0023] The resin having a structural unit represented by the above formula (1) and having a functional group without maleimide groups at both ends may have a structural unit represented by the following formula (3).

[0024]

Chemical formula

[0025] In the above formula (3), P 2 represents an aromatic group, and Q 2 represents a group having a substituted or unsubstituted aromatic structure.

[0026] In the above formula (3), P 2 is preferably an aromatic group having 5 to 50 carbon atoms. When P 2 is an aromatic group having 5 to 50 carbon atoms, the resulting adhesive film will be more excellent in heat resistance. That is, peeling during the high-temperature processing step can be further suppressed, and it is also possible to further prevent the occurrence of enhanced adhesion to the adherend or the occurrence of glue residue during peeling from the adherend.

[0027] In the above formula (3), Q 2 is preferably a group having a substituted or unsubstituted aromatic structure having 5 to 50 carbon atoms. When Q 2 is a group having a substituted or unsubstituted aromatic structure having 5 to 50 carbon atoms, the resulting adhesive film will be more excellent in heat resistance. That is, peeling during the high-temperature processing step can be further suppressed, and it is also possible to further prevent the occurrence of enhanced adhesion to the adherend or the occurrence of glue residue during peeling from the adherend.

[0028] Examples of the functional group having no maleimide group include an aliphatic group, an alicyclic group, an aromatic group, an acid anhydride group, an amino group, etc. Specifically, examples include unreacted terminal constituent groups of acid anhydrides and diamine compounds that are raw materials of resins having no maleimide group and having an imide skeleton as a repeating unit in the main chain. The resin having the structural unit represented by the above formula (1) and having functional groups having no maleimide group at both ends may have the same or different functional groups having no maleimide group at both ends.

[0029] In the resin having the structural unit represented by the above formula (1) and having a functional group having no maleimide group at both ends, the content ratio of the structural unit represented by the above formula (1) is preferably 30 mol% or more, more preferably 50 mol% or more, preferably 90 mol% or less, and more preferably 80 mol% or less. When the resin having the structural unit represented by the above formula (1) and having a functional group having no maleimide group at both ends has the structural unit represented by the above formula (3), the content ratio of the structural unit represented by the above formula (3) is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 20 mol% or more, preferably 50 mol% or less, and more preferably 30 mol% or less. In the structural unit represented by the above formula (1) and the structural unit represented by the above formula (3), when the content ratio of each structural unit is within the above range, the obtained adhesive film can further suppress peeling during the high-temperature processing step, and can be more easily peeled off when peeled from the adherend. Note that the structural unit represented by the above formula (1) and the structural unit represented by the above formula (3) may have a block structure composed of block components in which the respective structural units are continuously arranged, or may have a random structure in which the respective structural units are randomly arranged.

[0030] Examples of the method for producing a resin having no maleimide group and having an imide skeleton in the repeating unit of the main chain include a method of reacting a diamine compound with an aromatic acid anhydride.

[0031] As the above diamine compound, either an aliphatic diamine compound or an aromatic diamine compound can be used. By using an aliphatic diamine compound as the above diamine compound, the obtained adhesive film becomes more excellent in light transmittance. Further, the obtained adhesive film becomes more excellent in flexibility, can exhibit high followability with respect to an adherend having unevenness, and can be more easily peeled off at the time of peeling. In addition, by using an aromatic diamine compound as the diamine compound, the resulting adhesive film will be more excellent in heat resistance. The above diamine compound may be used alone or in combination of two or more.

[0032] Examples of the above aliphatic diamine compound include 1,10-diaminodecane, 1,12-diaminododecane, dimer diamine, 1,2-diamino-2-methylpropane, 1,2-diaminocyclohexane, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,7-diaminoheptane, 1,8-diaminomenthane, 1,8-diaminooctane, 1,9-diaminononane, 3,3'-diamino-N-methyldipropylamine, diaminomaleonitrile, 1,3-diaminopentane, bis(4-amino-3-methylcyclohexyl)methane, 1,2-bis(2-aminoethoxy)ethane, 3(4),8(9)-bis(aminomethyl)tricyclo(5.2.1.02,6)decane, and the like.

[0033] Among the above aliphatic diamine compounds, dimer diamine is preferable from the viewpoints of light transmittance, flexibility, and compatibility with a solvent or other components of a resin having no maleimide group and having an imide skeleton as a repeating unit in the main chain. Specific examples of the dimer diamine include dimer diamines capable of constituting at least one group selected from the group consisting of the group represented by the above formula (2-1), the group represented by the formula (2-2), the group represented by the formula (2-3), and the group represented by the formula (2-4).

[0034] Examples of the aromatic diamine compound include 9,10-diaminophenanthrene, 4,4'-diaminooctafluorobiphenyl, 3,7-diamino-2-methoxyfluorene, 4,4'-diaminobenzophenone, 3,4-diaminobenzophenone, 3,4-diaminotoluene, 2,6-diaminoanthraquinone, 2,6-diaminotoluene, 2,3-diaminotoluene, 1,8-diaminonaphthalene, 2,4-diaminotoluene, 2,5-diaminotoluene, 1,4-diaminoanthraquinone, 1,5-diaminoanthraquinone, 1,5-diaminonaphthalene, 1,2-diaminoanthraquinone, 2,4-cumenediamine, 1,3-bis(aminomethyl)benzene, 1,3-bis(aminomethyl)cyclohexane, 2-chloro-1,4-diaminobenzene, 1,4-diamino-2,5-dichlorobenzene, 1,4-diamino-2,5-dimethylbenzene, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, bis(amino-3-chlorophenyl)ethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane, 9,9'-bis(4-amino-3-ethylphenyl)fluorene, 2,3-diaminonaphthalene, 2,3-diaminophenol, bis(4-amino-5-methylphenyl)methane, bis(4-amino-3-methylphenyl)methane, bis(4-amino-3-ethylphenyl)methane, 4,4'-diaminophenyl sulfone, 3,3'-diaminophenyl sulfone, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, 4,4'-oxydianiline, 4,4'-diaminodiphenyl sulfide, 3,4'-oxydianiline, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-diamino-3,3'-dihydroxybiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-dimethoxybiphenyl, Bisaniline M, Bisaniline P, 9,9-bis(4-aminophenyl)fluorene, o-tolidine sulfone, 5,5'-methylenebis(anthranilic acid), 1,3-bis(4-aminophenoxy)-2,2-dimethylpropane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,3',5,5'-tetramethylbenzidine, 4,4'-diaminobenzanilide, 2,2-bis(4-aminophenyl)hexafluoropropane, polyoxyalkylenediamines (e.g., Jeffamine D-230, D-400, D-2000, and D-4000 manufactured by Huntsman), 1,3-cyclohexanebis(methylamine), m-xylylenediamine, p-xylylenediamine, etc. may be mentioned.,

[0035] Examples of the aromatic carboxylic anhydride include acid anhydrides of carboxylic acids such as pyromellitic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,4,5-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 3,3’,4,4’-benzophenonetetracarboxylic acid, 3,3’,4,4’-biphenyl ether tetracarboxylic acid, 3,3’,4,4’-biphenyltetracarboxylic acid, 2,3,5,6-pyridinetetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, 4,4’-sulfonyldiphthalic acid, 1-trifluoromethyl-2,3,5,6-benzenetetracarboxylic acid, 2,2’,3,3’-biphenyltetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2-bis(2,3-dicarboxyphenyl)propane, 1,1-bis(2,3-dicarboxyphenyl)ethane, 1,1-bis(3,4-dicarboxyphenyl)ethane, bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)sulfone, bis(3,4-dicarboxyphenyl)ether, benzene-1,2,3,4-tetracarboxylic acid, 2,3,2’,3’-benzophenonetetracarboxylic acid, 2,3,3’,4’-benzophenonetetracarboxylic acid, phenanthrene-1,8,9,10-tetracarboxylic acid, pyrazine-2,3,5,6-tetracarboxylic acid, thiophene-2,3,4,5-tetracarboxylic acid, 2,3,3’,4’-biphenyltetracarboxylic acid, 4,4’-bis(3,4-dicarboxyphenoxy)diphenyl sulfide, 4,4’-(4,4’-isopropylidenediphenoxy)-bis(phthalic acid).

[0036] In 100 parts by mass of the compound having the imide bond, the lower limit of the content of the resin having no maleimide group and having an imide skeleton as a repeating unit of the main chain is preferably 10 parts by mass, and the upper limit is preferably 90 parts by mass. When the content of the resin having no maleimide group and having an imide skeleton as a repeating unit of the main chain is within this range, the resulting adhesive film can be more easily peeled off from the adherend. From the viewpoint of further enhancing the re-peelability, the lower limit of the content of the resin having no maleimide group and having an imide skeleton as a repeating unit of the main chain is more preferably 20 parts by mass, and the upper limit is more preferably 80 parts by mass.

[0037] The resin having an imide skeleton as a repeating unit of the main chain preferably contains a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain. By including a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain, the resulting adhesive film polymerizes and crosslinks uniformly and rapidly as a whole by irradiation with light or the like, and the elastic modulus increases, resulting in a large decrease in adhesive strength. Therefore, it is possible to further prevent the occurrence of enhanced adhesion or the generation of adhesive residue during peeling. When the resin having an imide skeleton as a repeating unit of the main chain contains a resin having no maleimide group and having an imide skeleton as a repeating unit of the main chain, in addition to the resin having no maleimide group and having an imide skeleton as a repeating unit of the main chain, it is preferable to further include a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain.

[0038] Examples of the functional group having a carbon-carbon double bond include an optionally substituted maleimide group, a citraconimide group, a vinyl ether group, an allyl group, a (meth)acryloyl group, etc. Among them, an optionally substituted maleimide group is preferable because higher heat resistance can be obtained. Note that the carbon-carbon double bond contained in the aromatic ring is not treated as the carbon-carbon double bond of the functional group having a carbon-carbon double bond. In addition, in this specification, "(meth)acryloyl" means acryloyl or methacryloyl.

[0039] The resin having a functional group with a carbon-carbon double bond and having an imide skeleton as a repeating unit in the main chain preferably has a functional group equivalent weight (weight-average molecular weight / number of functional groups with a carbon-carbon double bond) of the functional group with a carbon-carbon double bond of 4000 or less. When the functional group equivalent weight of the functional group with a carbon-carbon double bond is 4000 or less, the resulting adhesive film has more excellent heat resistance. This is presumably because, by having a functional group with a carbon-carbon double bond in the molecule of the resin at a density of a certain level or more, the crosslinking distance becomes shorter, and thus the promotion of adhesion is more suppressed. The functional group equivalent weight of the functional group with a carbon-carbon double bond is more preferably 3000 or less, and even more preferably 2000 or less. Also, although there is no particular preferable lower limit for the functional group equivalent weight of the functional group with a carbon-carbon double bond, the substantial lower limit is about 600.

[0040] The resin having a functional group with a carbon-carbon double bond and having an imide skeleton as a repeating unit in the main chain preferably has a weight average molecular weight of 1,000 or more and 100,000 or less. When the weight average molecular weight of the resin having a functional group with a carbon-carbon double bond and having an imide skeleton as a repeating unit in the main chain is 1,000 or more, the formation of the adhesive layer becomes easy, and the resulting adhesive film exhibits a certain degree of flexibility. Therefore, it can exhibit high followability with respect to an adherend having unevenness and can be more easily peeled off during peeling. When the weight average molecular weight of the resin having a functional group with a carbon-carbon double bond and having an imide skeleton as a repeating unit in the main chain is 100,000 or less, it is possible to prevent the solubility of the resin having a functional group with a carbon-carbon double bond and having an imide skeleton as a repeating unit in the main chain in a solvent from becoming too low. More preferably, the weight average molecular weight of the resin having a functional group with a carbon-carbon double bond and having an imide skeleton as a repeating unit in the main chain is 1,500 or more and 50,000 or less, and still more preferably 2,000 or more and less than 20,000.

[0041] In the resin having a functional group with a carbon-carbon double bond and having an imide skeleton as a repeating unit in the main chain, the functional group with a carbon-carbon double bond may be located either in the side chain or at the terminal, but it is preferably present at both terminals, and more preferably present in the side chain in addition to both terminals. The functional groups with carbon-carbon double bonds at both terminals of the resin having a functional group with a carbon-carbon double bond and having an imide skeleton as a repeating unit in the main chain have high reactivity, and the adhesive film can be more sufficiently cured by irradiation with light or the like. As a result, it is possible to further prevent adhesion enhancement and the occurrence of adhesive residue during peeling. Furthermore, due to the presence of a functional group having a carbon-carbon double bond in the side chain of a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain, the resulting adhesive film becomes more excellent in heat resistance. This is presumably because the adhesion enhancement is further suppressed by shortening the crosslinking distance. Also, due to the presence of a functional group having a carbon-carbon double bond in the side chain of a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain, it becomes easy to adjust the functional group equivalent to 4000 or less while setting the weight average molecular weight to 1000 or more. As a result, the adhesive film has sufficient initial adhesive strength and can more effectively prevent adhesion enhancement and the occurrence of glue residue during peeling.

[0042] As described above, in a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain, the functional group having a carbon-carbon double bond may be located either in the side chain or at the terminal. When either the side chain or the terminal has a functional group other than the functional group having a carbon-carbon double bond (a functional group not having a carbon-carbon double bond), examples of the functional group not having a carbon-carbon double bond include an aliphatic group, an alicyclic group, an aromatic group, an acid anhydride group, an amino group, and the like. Specifically, examples include unreacted terminal constituent groups of acid anhydrides and diamine compounds that are raw materials for the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain. When the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain has two or more functional groups not having a carbon-carbon double bond in the side chain or at the terminal, the respective functional groups not having a carbon-carbon double bond may be the same or different.

[0043] Specific examples of the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain include, for example, a resin having a structural unit represented by the above formula (1) and having a functional group having a carbon-carbon double bond in at least one of the terminal and the side chain.

[0044] The resin having a structural unit represented by the above formula (1) and having a functional group having a carbon-carbon double bond at least in either the terminal or the side chain may have at least one structural unit selected from the group consisting of a structural unit represented by the following formula (4-1) and a structural unit represented by the following formula (4-2).

[0045]

Chemical formula

[0046] In formula (4-1), P 3 represents an aromatic group, Q 3 represents a group having a substituted or unsubstituted aromatic structure. In formula (4-2), P 4 represents an aromatic group, R represents a substituted or unsubstituted branched aliphatic group or aromatic group, and X represents a functional group having a carbon-carbon double bond.

[0047] P in the above formula (4-1) 3 and P in the above formula (4-2) 4 are preferably aromatic groups having 5 to 50 carbon atoms. By P 3 and P 4 being aromatic groups having 5 to 50 carbon atoms, the resulting adhesive film becomes more excellent in heat resistance. That is, peeling during the high-temperature processing step can be further suppressed, and it is possible to further prevent the occurrence of enhanced adhesion to the adherend or the generation of glue residue during peeling from the adherend.

[0048] In the above formula (4-1), Q 3 is preferably a group having a substituted or unsubstituted aromatic structure having 5 to 50 carbon atoms. By Q 3 being a group having a substituted or unsubstituted aromatic structure having 5 to 50 carbon atoms, the resulting adhesive film becomes more excellent in heat resistance. That is, peeling during the high-temperature processing step can be further suppressed, and it is possible to further prevent the occurrence of enhanced adhesion to the adherend or the generation of glue residue during peeling from the adherend.

[0049] In the above formula (4-2), R is preferably a substituted or unsubstituted branched aliphatic group or aromatic group having 2 to 100 carbon atoms. When R is a substituted or unsubstituted branched aliphatic group or aromatic group having 2 to 100 carbon atoms, the resulting adhesive film becomes more excellent in flexibility, can exhibit high followability with respect to an adherend having unevenness, and can be more easily peeled off at the time of peeling.

[0050] In the above formula (4-2), R is an aromatic group having an aromatic ester group or an aromatic ether group, and the aromatic ester group or the aromatic ether group in the R is preferably bonded to X. Here, the "aromatic ester group" means a group in which an ester group is directly bonded to an aromatic ring, and the "aromatic ether group" means a group in which an ether group is directly bonded to an aromatic ring. By making the portion bonded to the ester group or the ether group an aromatic group in this way, the resulting adhesive film becomes more excellent in heat resistance. That is, peeling during the high-temperature processing step can be further suppressed, and it is also possible to further prevent the occurrence of adhesion enhancement to the adherend or the occurrence of glue residue at the time of peeling from the adherend. On the other hand, since the carbon-carbon double bond in X does not conjugate with R when X is bonded to R via an aromatic ester group or an aromatic ether group, polymerization crosslinking when heated or irradiated with light is not hindered.

[0051] In the resin having a structural unit represented by the above formula (1) and having a functional group having a carbon-carbon double bond at least in either the terminal or the side chain, the content ratio of the structural unit represented by the above formula (1) is preferably 30 mol% or more, more preferably 50 mol% or more, preferably 90 mol% or less, and more preferably 80 mol% or less. When the resin having the structural unit represented by the above formula (1) and having a functional group having a carbon-carbon double bond at least in either the terminal or the side chain has the structural unit represented by the above formula (4-1), the content ratio of the structural unit represented by the above formula (4-1) is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 20 mol% or more, and preferably 50 mol% or less, more preferably 30 mol% or less. When the resin having the structural unit represented by the above formula (1) and having a functional group having a carbon-carbon double bond at least in either the terminal or the side chain has the structural unit represented by the above formula (4-2), the content ratio of the structural unit represented by the above formula (4-2) is preferably 10 mol% or more, more preferably 20 mol% or more, and preferably 50 mol% or less, more preferably 30 mol% or less. In the structural unit represented by the above formula (1), the structural unit represented by the above formula (4-1), and the structural unit represented by the above formula (4-2), by having the content ratio of each structural unit within the above range, the obtained adhesive film can further suppress peeling during the high-temperature processing step, and can be more easily peeled off when peeled from the adherend. The structural unit represented by the above formula (1), the structural unit represented by the above formula (4-1), and the structural unit represented by the above formula (4-2) may have a block structure composed of block components in which the respective structural units are continuously arranged, or may have a random structure in which the respective structural units are randomly arranged.

[0052] Examples of the method for producing a resin having a functional group having the above carbon-carbon double bond and having an imide skeleton in the repeating unit of the main chain include the following methods. That is, first, a diamine compound and an aromatic acid anhydride are reacted to prepare an imide compound. Next, a compound having a functional group reactive with the functional group and a functional group having a carbon-carbon double bond (hereinafter also referred to as "functional group-containing unsaturated compound") is reacted with the functional group of the imide compound, whereby a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain can be obtained. Also, by reacting a diamine compound and an aromatic acid anhydride to prepare an imide compound, and further reacting, for example, maleic anhydride or the like at the terminal of the imide compound, a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain can be obtained.

[0053] As the diamine compound and the aromatic acid anhydride used in the method for producing a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain, those similar to those used in the method for producing a resin having no maleimide group and having an imide skeleton as a repeating unit of the main chain can be used.

[0054] The functional group-containing unsaturated compound is selected and used according to the functional group at the terminal or side chain of the imide compound. For example, when the functional group at the terminal or side chain of the imide compound is a hydroxyl group, examples of the functional group-containing unsaturated compound include a maleimide compound having a carboxy group, a vinyl compound having an ether group, an allyl compound having a glycidyl group, an allyl ether compound having a glycidyl group, a vinyl ether compound having a glycidyl group, an allyl compound having an isocyanate group, a (meth)acryloyl compound having an isocyanate group, and the like. Also, for example, when the functional group at the terminal or side chain of the imide compound is a carboxy group, examples of the functional group-containing unsaturated compound include an allyl compound having a hydroxyl group, an allyl compound having a glycidyl group, an allyl ether compound having a glycidyl group, a vinyl ether compound having a glycidyl group, and the like. Examples of the maleimide compound having a carboxy group include maleimide acetate, maleimide propionic acid, maleimide butyric acid, maleimide hexanoic acid, trans-4-(N-maleimidomethyl) cyclohexane-1-carboxylic acid, 19-maleimide-17-oxo-4,7,10,13-tetraoxa-16-azanonadecanoic acid, and the like. Examples of the vinyl compound having an ether group include butyl vinyl ether and the like. Examples of the allyl compound having a glycidyl group include diallyl monoglycidyl isocyanurate and the like. Examples of the allyl ether compound having a glycidyl group include allyl glycidyl ether, glycerin diallyl monoglycidyl ether, and the like. Examples of the vinyl ether compound having a glycidyl group include glycidyloxyethyl vinyl ether, glycidyloxybutyl vinyl ether, glycidyloxyhexyl vinyl ether, glycidyldiethylene glycol vinyl ether, glycidylcyclohexanedimethanol monovinyl ether, and the like. Examples of the allyl compound having an isocyanate group include allyl isocyanate and the like. Examples of the (meth)acryloyl compound having an isocyanate group include 2-(meth)acryloyloxyethyl isocyanate and the like. Examples of the allyl compound having a hydroxyl group include trimethylolpropane diallyl ether, pentaerythritol triallyl ether, and the like.

[0055] In 100 parts by mass of the compound having an imide bond, the preferable lower limit of the content of the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain is 10 parts by mass, and the preferable upper limit is 100 parts by mass. When the content of the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain in 100 parts by mass of the compound having an imide bond is within this range, the adhesive film can be peeled off more easily during peeling. From the viewpoint of further enhancing the re-peelability, the more preferable lower limit of the content of the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain in 100 parts by mass of the compound having an imide bond is 20 parts by mass, and the further preferable lower limit is 30 parts by mass, the more preferable upper limit is 90 parts by mass, the further preferable upper limit is 80 parts by mass, and the even more preferable upper limit is 70 parts by mass.

[0056] When the resin having an imide skeleton as a repeating unit of the main chain does not have the maleimide group and contains a resin having an imide skeleton as a repeating unit of the main chain, the compound having an imide bond preferably further contains a polyfunctional monomer or polyfunctional oligomer (hereinafter also simply referred to as "polyfunctional monomer or polyfunctional oligomer") having two or more functional groups having a carbon-carbon double bond in the molecule and having a molecular weight of 5000 or less. Also, when the resin having an imide skeleton as a repeating unit of the main chain has a functional group having a carbon-carbon double bond and contains a resin having an imide skeleton as a repeating unit of the main chain, the compound having an imide bond may further contain the polyfunctional monomer or polyfunctional oligomer. By including the polyfunctional monomer or polyfunctional oligomer, the three-dimensional crosslinking of the adhesive film by irradiation with light or the like becomes more efficient, and it is possible to more effectively prevent the occurrence of adhesion enhancement and the generation of adhesive residue during peeling.

[0057] In addition, when the resin having the imide skeleton as a repeating unit of the main chain itself has no reactivity, the compound having the imide bond needs to have reactivity as a whole by further containing other components having reactive functional groups. As such other components having reactive functional groups, it is preferable to use the polyfunctional monomer or polyfunctional oligomer. Examples of the case where the resin having the imide skeleton as a repeating unit of the main chain itself has no reactivity include the case where the resin having the imide skeleton as a repeating unit of the main chain does not have the maleimide group and only contains the resin having the imide skeleton as a repeating unit of the main chain.

[0058] Examples of the functional group having a carbon-carbon double bond in the polyfunctional monomer or polyfunctional oligomer include an optionally substituted maleimide group, citraconimide group, vinyl ether group, allyl group, (meth)acryloyl group, etc. Among them, an optionally substituted maleimide group is preferable because higher heat resistance can be obtained. In particular, the polyfunctional monomer or polyfunctional oligomer is preferably a bismaleimide compound.

[0059] The polyfunctional monomer or polyfunctional oligomer preferably has a group derived from a diamine compound. As the diamine compound, either an aliphatic diamine compound or an aromatic diamine compound can be used, but an aliphatic diamine compound is preferable. That is, it is more preferable that the polyfunctional monomer or polyfunctional oligomer has an aliphatic group derived from a diamine compound. By using an aliphatic diamine compound as the diamine compound, the obtained adhesive film becomes more excellent in light transmittance. In addition, the obtained adhesive film becomes more excellent in flexibility, can exhibit high followability with respect to an adherend having unevenness, and can be more easily peeled off at the time of peeling.

[0060] Among the above aliphatic diamine compounds, dimer diamines as described above are preferred from the viewpoints of light transmittance, flexibility, and compatibility with solvents and other components of the above polyfunctional monomer or polyfunctional oligomer.

[0061] The preferable lower limit of the content of the polyfunctional monomer or polyfunctional oligomer in 100 parts by mass of the compound having the imide bond is 5 parts by mass, and the preferable upper limit is 90 parts by mass. When the content of the polyfunctional monomer or polyfunctional oligomer is within this range, the adhesive film can be more easily peeled off during peeling. From the viewpoint of further enhancing the re-peelability, the more preferable lower limit of the content of the polyfunctional monomer or polyfunctional oligomer is 10 parts by mass, and the more preferable upper limit is 50 parts by mass.

[0062] When the compound having the imide bond contains a resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain and the polyfunctional monomer or polyfunctional oligomer, the preferable lower limit of the total content of the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain and the polyfunctional monomer or polyfunctional oligomer in 100 parts by mass of the compound having the imide bond is 20 parts by mass, and the preferable upper limit is 80 parts by mass. When the total content of the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain and the polyfunctional monomer or polyfunctional oligomer is within this range, the adhesive film can be more easily peeled off during peeling. From the viewpoint of further enhancing the re-peelability, the more preferable lower limit of the total content of the resin having a functional group having a carbon-carbon double bond and having an imide skeleton as a repeating unit of the main chain and the polyfunctional monomer or polyfunctional oligomer is 30 parts by mass, the further preferable lower limit is 40 parts by mass, the even more preferable lower limit is 50 parts by mass, and the more preferable upper limit is 70 parts by mass.

[0063] The compound having the imide bond preferably includes a compound having a maleimide group. By containing the compound having the maleimide group, the resulting adhesive film will be more excellent in heat resistance. The compound having the maleimide group is preferably a bismaleimide compound or a resin having a maleimide group and having an imide skeleton as a repeating unit in the main chain. That is, the compound having the imide bond preferably includes the bismaleimide compound as the above-mentioned polyfunctional monomer or polyfunctional oligomer, or the compound having the imide bond has a functional group having a carbon-carbon double bond and has an imide skeleton as a repeating unit in the main chain, and preferably includes a resin having a maleimide group as the functional group having a carbon-carbon double bond of the resin.

[0064] The preferable upper limit of the content ratio of the compound having the imide bond in the above adhesive layer is 99% by mass. By the content ratio of the compound having the imide bond being 99% by mass or less, the releasability from the adherend can be further enhanced. The more preferable upper limit of the content ratio of the compound having the imide bond is 98% by mass, the further preferable upper limit is 96% by mass, and the even more preferable upper limit is 90% by mass. Also, the preferable lower limit of the content ratio of the compound having the imide bond is 5% by mass. By the content ratio of the compound having the imide bond being 5% by mass or more, the resulting adhesive film will be more excellent in heat resistance, and peeling during the high-temperature processing step can be further suppressed. Also, the promotion of adhesion during the high-temperature processing step can be further suppressed. The more preferable lower limit of the content ratio of the compound having the imide bond is 10% by mass, and the further preferable lower limit is 20% by mass.

[0065] The above adhesive layer may contain a polymerization initiator. Since the above-mentioned adhesive layer contains a polymerization initiator, the adhesive layer is more likely to cure, and the enhancement of the adhesion of the adhesive film to the adherend during the high-temperature processing step can be more suppressed. Therefore, the resulting adhesive film has better peelability from the adherend and can be more easily peeled off when peeled from the adherend.

[0066] The above-mentioned polymerization initiator may be a photoinitiator or a thermal polymerization initiator. From the viewpoint of storage stability, a photoinitiator is preferred. In addition, these polymerization initiators may be used alone or in combination of two or more.

[0067] Examples of the above-mentioned photoinitiator include those activated by irradiating light with a wavelength of 250 to 800 nm. Among them, since it is difficult to overlap with the absorption wavelength of the compound having the above-mentioned imide bond and the photoinitiator is sufficiently activated when the adhesive film is irradiated with light, the preferred lower limit of the molar extinction coefficient of the photoinitiator at 405 nm is 10 ml / (g·cm), the more preferred lower limit is 200 ml / (g·cm), and the further preferred lower limit is 405 ml / (g·cm). Also, there is no particular upper limit for the molar extinction coefficient at 405 nm, but about 1.0×10 6 ml / (g·cm) is the substantial upper limit.

[0068] Examples of the above-mentioned photoinitiator include acetophenone derivatives, benzoin ether compounds, ketal derivatives, phosphine oxide derivatives, oxime ester compounds, and the like. Examples of the above-mentioned acetophenone derivatives include methoxyacetophenone, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one, and the like. Examples of the above-mentioned benzoin ether compounds include benzoin propyl ether, benzoin isobutyl ether, and the like. Examples of the ketal derivative include benzyldimethyl ketal, acetophenone diethyl ketal, and the like. Examples of the phosphine oxide derivative include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and the like. Examples of the oxime ester compound include 1-(O-acetyloxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone, 1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime)-1,2-octadione, and the like. Examples of the photopolymerization initiator also include bis(η5-cyclopentadienyl)titanocene derivative compounds, benzophenone, Michler's ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethyl phenyl propane, and the like. These photopolymerization initiators may be used alone or in combination of two or more.

[0069] The content of the polymerization initiator preferably has a lower limit of 0.1 part by mass and an upper limit of 10 parts by mass with respect to 100 parts by mass of the compound having an imide bond. When the content of the polymerization initiator is within this range, the entire adhesive layer is uniformly and rapidly polymerized and crosslinked by irradiation with light, heating, etc., and the elastic modulus increases, so that the adhesive force is greatly reduced, causing adhesion enhancement or residue of the adhesive during peeling can be prevented. A more preferable lower limit of the content of the polymerization initiator is 0.3 part by mass, and a more preferable upper limit is 5 parts by mass.

[0070] The adhesive layer may contain an ultraviolet absorber. By containing an ultraviolet absorber in the adhesive layer, the light absorption property of the adhesive layer in the ultraviolet region is further enhanced. Therefore, even when irradiating a low-energy laser beam when laser-peeling the support from the adhesive film of the present invention, the support can be peeled more efficiently.

[0071] Examples of the above ultraviolet absorber include triazine-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and the like. Among them, from the viewpoint of further improving the heat resistance of the obtained adhesive film, it is preferable that the above ultraviolet absorber contains a triazine-based ultraviolet absorber.

[0072] Examples of the above triazine-based ultraviolet absorber include Tinuvin400, Tinuvin405, Tinuvin460, Tinuvin477, Tinuvin479, Tinuvin1577ED, Tinuvin1600 (all manufactured by BASF), Adeka Stab LA46, and Adeka Stab LA-F70 (all manufactured by ADEKA). Among them, Tinuvin400, Tinuvin479, and Tinuvin1600 are preferable.

[0073] With respect to 100 parts by mass of the compound having the above imide bond, the preferable lower limit of the content of the above ultraviolet absorber is 1 part by mass, and the preferable upper limit is 30 parts by mass. When the content of the above ultraviolet absorber is 1 part by mass or more, the light absorption property in the ultraviolet region of the above adhesive layer is further enhanced, so that even when irradiating the support with low-energy laser light when laser-peeling the support from the adhesive film of the present invention, the support can be peeled off more efficiently. If the content of the above ultraviolet absorber is 30 parts by mass or less, the obtained adhesive film can be easily peeled off from the adherend even after the heating step. The more preferable lower limit of the above ultraviolet absorber is 5 parts by mass, the further preferable lower limit is 7 parts by mass, the more preferable upper limit is 20 parts by mass, and the further preferable upper limit is 15 parts by mass.

[0074] The above adhesive layer may further contain a release agent. Examples of the release agent include silicone-based release agents, fluorine-based release agents, acrylic-based release agents, and the like. Since these release agents have excellent heat resistance, when the adhesive layer contains the release agent, it is possible to prevent the adhesive layer from burning even after undergoing a high-temperature processing step of 300°C or higher. Furthermore, when the resulting adhesive film is peeled off, it bleeds out to the adherend interface, making the peeling easier. Among them, silicone-based release agents are preferable from the viewpoints of being environmentally friendly and easy to dispose of. Also, from the viewpoint of preventing contamination of the adherend by silicone, acrylic-based release agents are preferable.

[0075] The release agent may have a functional group capable of crosslinking with a resin having the imide skeleton as a repeating unit of the main chain. When the release agent has a functional group capable of crosslinking with a resin having the imide skeleton as a repeating unit of the main chain, the release agent undergoes a chemical reaction with the resin having the imide skeleton as a repeating unit of the main chain or the polyfunctional monomer or polyfunctional oligomer and is incorporated by irradiation with light or reaction with a crosslinking agent or the like. Therefore, it is possible to suppress the release agent from adhering to and contaminating the adherend. Examples of the functional group capable of crosslinking with the resin having the imide skeleton as a repeating unit of the main chain or the polyfunctional monomer or polyfunctional oligomer include a carboxy group, a functional group having a radically polymerizable unsaturated bond (e.g., a vinyl group, a (meth)acryloyl group, an optionally substituted maleimide group), a hydroxy group, an amide group, an isocyanate group, an epoxy group, and the like.

[0076] Examples of the acrylic-based release agent include acrylic copolymers used for imparting leveling properties, and specifically, BYK-394, BYK-350, BYK-381 (all manufactured by BYK Chemie), Disparlon 1970 (manufactured by Kusumoto Chemicals, Ltd.), and the like.

[0077] Examples of the silicone-based release agent include silicone oil, silicone diacrylate, silicone-based graft copolymers, etc. Specifically, a silicone compound having a siloxane skeleton in the main chain and a functional group having a carbon-carbon double bond in the side chain or at the terminal is preferable. As the silicone compound having a siloxane skeleton in the main chain and a functional group having a carbon-carbon double bond in the side chain or at the terminal, at least one selected from the group consisting of a silicone compound represented by the following formula (5-1), a silicone compound represented by the following formula (5-2), and a silicone compound represented by the following formula (5-3) is preferable. These silicone compounds are particularly excellent in heat resistance and have a high polarity, so that bleed-out from the adhesive layer is easy.

[0078]

Chemical formula

[0079] In the above formulas (5-1) to (5-3), X, and in the above formulas (5-1) and (5-3), Y each independently represent an integer of 0 or more and 1200 or less. In the above formulas (5-1) to (5-3), R represents a functional group having a carbon-carbon double bond.

[0080] Examples of the functional group having a carbon-carbon double bond represented by R in the above formulas (5-1) to (5-3) include an optionally substituted maleimide group, citraconimide group, vinyl ether group, allyl group, (meth)acryloyl group, etc. Among them, an optionally substituted maleimide group is preferable because the resulting adhesive film becomes more excellent in heat resistance. In the above formulas (5-1) to (5-3), when a plurality of Rs are present, each R may be the same or different.

[0081] Among the silicone compounds represented by the above formulas (5-1) to (5-3), commercially available ones include, for example, EBECRYL 350, EBECRYL 1360 (both manufactured by Daicel Ornex Co., Ltd.), and the like. Also, BYK-UV 3500 (manufactured by BYK-Chemie), TEGO RAD 2250 (manufactured by Evonik) (both with R being an acryloyl group), and the like can be mentioned.

[0082] Examples of the above fluorine-based release agent include hydrocarbon compounds having a fluorine atom.

[0083] The content of the above release agent preferably has a lower limit of 0.1 part by mass and an upper limit of 20 parts by mass with respect to 100 parts by mass of the compound having the above imide bond. When the content of the above release agent is within this range, the resulting adhesive film is excellent in re-peelability without contaminating the adherend. From the viewpoint of further enhancing the re-peelability while suppressing the contamination of the adherend, the more preferable lower limit of the content of the above release agent is 0.3 part by mass, and the more preferable upper limit is 10 parts by mass. In addition, since the adhesive film of the present invention is excellent in heat resistance, sufficient effects can be exhibited even when the content of the above release agent is relatively small. Therefore, the possibility of contaminating the adherend by the above silicone-based release agent or fluorine-based release agent can be further reduced.

[0084] The above adhesive layer may further contain an inorganic filler. By containing the above inorganic filler, the resulting adhesive film can suppress a decrease in the elastic modulus at high temperatures, and even when a high-temperature processing step of 260 °C or higher is performed, peeling during the high-temperature processing step can be further suppressed.

[0085] Examples of the above inorganic filler include inorganic fillers composed of at least one selected from the group consisting of oxides of silicon, titanium, aluminum, calcium, boron, magnesium, and zirconia, and composites thereof. Among them, silica and talc are preferable because they are inexpensive and easily available as commercial products.

[0086] The above inorganic filler may be surface-modified. Examples of the modifying functional group for surface-modifying the above inorganic filler include an alkylsilane group, a methacryloyl group, and a dimethylsiloxane group. Among them, the dimethylsiloxane group is preferred because it has appropriate hydrophobicity.

[0087] The preferred lower limit of the average particle diameter of the above inorganic filler is 5 nm, and the preferred upper limit is 30 μm. When the average particle diameter of the above inorganic filler is within this range, the resulting adhesive film can be more effectively prevented from peeling during the high-temperature processing step, and can be easily peeled by a peeling process during peeling. The more preferred lower limit of the average particle diameter of the above inorganic filler is 10 nm, the more preferred upper limit is 20 μm, and the further preferred lower limit is 15 nm, and the further preferred upper limit is 15 μm. The average particle diameter can be determined, for example, by observing 50 arbitrary inorganic fillers with an electron microscope or an optical microscope and calculating the average value of the particle diameters of each inorganic filler, or by performing laser diffraction particle size distribution measurement.

[0088] The content of the above inorganic filler preferably has a lower limit of 1 part by mass and a preferred upper limit of 20 parts by mass with respect to 100 parts by mass of the compound having the above imide bond. When the content of the above inorganic filler is within this range, the resulting adhesive film can be more effectively prevented from peeling during the high-temperature processing step, and can be easily peeled by a peeling process during peeling. The more preferred lower limit of the content of the above inorganic filler is 3 parts by mass, the more preferred upper limit is 15 parts by mass, the further preferred lower limit is 5 parts by mass, and the further preferred upper limit is 10 parts by mass.

[0089] The above adhesive layer may contain a gas generating agent. By containing the above gas generating agent, even after undergoing a high-temperature processing step of 260°C or higher, the gas generated by irradiating light or the like is released at the interface with the adherend, so that the adhesive film can be more easily peeled from the adherend without leaving glue residue. Further, even when peeling the adhesive film from a thin adherend after performing a high-temperature processing step of 260°C or higher, damage to the adherend can be prevented.

[0090] The above gas generating agent preferably has a weight loss rate at 300°C of 5% or less when heated at a heating rate of 10°C / min from 30°C to 300°C in a nitrogen atmosphere by TG-DTA (thermogravimetry-differential thermal analysis) measurement. If the above weight loss rate is 5% or less, the decomposition of the above gas generating agent is less likely to occur even when performing a high-temperature processing step of 260°C or higher, and the above adhesive film becomes more excellent in heat resistance. That is, peeling can be further suppressed during the high-temperature processing step, and it is possible to further prevent the occurrence of enhanced adhesion or glue residue during peeling. The above TG-DTA (thermogravimetry-differential thermal analysis) measurement can be performed using, for example, a TG-DTA apparatus (manufactured by Hitachi High-Tech Science Corporation, "STA7200RV") or the like.

[0091] Examples of the above gas generating agent include a gas generating agent that generates gas by heating, a gas generating agent that generates gas by irradiating light, and the like. These gas generating agents may be used alone or in combination of two or more. Among them, from the viewpoint of preventing the decomposition of the gas generating agent in the high-temperature processing step, a gas generating agent that generates gas by irradiating light is preferable, and a gas generating agent that generates gas by irradiating ultraviolet light is more preferable. Examples of the gas generating agent include tetrazole compounds or their salts, triazole compounds or their salts, azo compounds, azide compounds, xanthone acetic acid, carbonates, and the like. These gas generating agents may be used alone or in combination of two or more. Among them, tetrazole compounds or their salts are preferred because of their particularly excellent heat resistance.

[0092] The content of the gas generating agent preferably has a lower limit of 5 parts by mass and an upper limit of 50 parts by mass with respect to 100 parts by mass of the compound having the imide bond. When the content of the gas generating agent is within this range, the resulting adhesive film is particularly excellent in re-peelability. A more preferable lower limit of the content of the gas generating agent is 8 parts by mass, and a more preferable upper limit is 30 parts by mass.

[0093] The above adhesive layer may contain known additives such as photosensitizers, heat stabilizers, antioxidants, antistatic agents, plasticizers, surfactants, and waxes as long as the effects of the present invention are not impaired.

[0094] The adhesive layer has a lower limit of the glass transition temperature (Tg) of 0°C. When the glass transition temperature of the adhesive layer is 0°C or higher, the heat resistance of the adhesive layer is improved, and peeling during the high-temperature processing step of the resulting adhesive film can be prevented. When the adhesive film of the present invention is a double-sided adhesive film described later, it is sufficient that the glass transition temperature (Tg) of one adhesive layer is 0°C or higher, but it is preferable that the glass transition temperatures (Tg) of both adhesive layers are 0°C or higher. A preferable lower limit of the glass transition temperature of the adhesive layer is 3°C, and a more preferable lower limit is 5°C. Further, the preferable upper limit of the glass transition temperature of the adhesive layer is 200°C. When the glass transition temperature of the adhesive layer is 200°C or lower, it becomes possible to easily peel without damaging the adherend at the time of peeling. When the adhesive film of the present invention is a double-sided adhesive film described later, it is more preferable that the glass transition temperatures (Tg) of both adhesive layers are 200°C or lower. A more preferable upper limit of the glass transition temperature of the adhesive layer is 150°C, and a further preferable upper limit is 100°C.

[0095] The glass transition temperature of the above-mentioned adhesive layer can be obtained, for example, by dynamic viscoelasticity measurement or the like. Specifically, for the adhesive film, using a dynamic viscoelasticity measuring device (manufactured by IT Measurement and Control Co., Ltd., such as "DVA-200"), under the measurement conditions of tensile mode, heating rate of 10 °C / min, measurement temperature of -50 °C to 300 °C, and frequency of 10 Hz, dynamic viscoelasticity measurement is performed. Among the maxima of the measured loss tangent, the temperature at which the maximum due to the micro-Brownian motion of the adhesive layer appears is taken as the glass transition temperature. When there are multiple maxima of the measured loss tangent, the maximum value of the loss tangent on the lowest temperature side is taken as the glass transition temperature of the adhesive layer. In addition, in calculating the glass transition temperature of the above-mentioned adhesive layer, a measurement sample can be prepared by removing the substrate and separating only the adhesive layer, and then the measurement can be carried out. As a method for removing the substrate layer, as long as it avoids treatment using a solvent, treatment involving a chemical reaction, treatment at a high temperature, etc. to avoid denaturation of the adhesive layer, it is not particularly limited. As a specific method, after bonding the adhesive layers together, an appropriate temperature and peeling rate are selected, and the substrate layer and the adhesive layer are peeled by peeling, and the method of removing the substrate layer, or the method of physically grinding the substrate layer can be selected. A sheet composed only of the adhesive layer may be separately prepared and the measurement may be carried out using the sheet as the measurement sample.

[0096] The adhesive layer when measuring the above-mentioned glass transition temperature may be in an uncured state or in a cured state. When using a cured adhesive layer, as a method for curing the above-mentioned adhesive layer, for example, a method of irradiating with light having a wavelength of 405 nm by an ultra-high pressure mercury lamp at an illuminance of 80 mW / cm 2 for 300 seconds, a method of heating at 200 °C for 30 minutes, etc. can be mentioned.

[0097] As a method for adjusting the glass transition temperature of the above-mentioned adhesive layer, for example, a method of changing the composition of the adhesive layer (for example, a method of adding an inorganic filler, etc.), a method of adjusting the degree of crosslinking of a compound having an imide bond, etc. can be mentioned.

[0098] The adhesive film of the present invention has a base material. Since the adhesive film of the present invention has a base material, the handleability of the adhesive film of the present invention is improved. Although the adhesive film of the present invention has a base material, heat shrinkage of the base material during the high-temperature processing step can be suppressed, and peeling of the obtained adhesive film during the high-temperature processing step can be prevented.

[0099] The above base material preferably contains a resin excellent in heat resistance. Examples of the resin excellent in heat resistance include a resin (A1) having a repeating unit containing at least one selected from the group consisting of an ether bond, a ketone group, and an imide bond in the main chain skeleton, a polyamide resin, etc. Among them, it is preferable to contain the above resin (A1). Since the above resin (A1) is particularly excellent in heat resistance, when the base material contains the above resin (A1), the heat resistance of the base material is further improved. As a result, heat shrinkage of the base material during the high-temperature processing step can be suppressed, and peeling of the obtained adhesive film during the high-temperature processing step can be further prevented. Such a resin excellent in heat resistance may be used alone or in combination of two or more.

[0100] Examples of the above resin (A1) include polyetheretherketone (PEEK), polyetherimide (PEI), etc.

[0101] In the case where the adhesive layer is cured by irradiation with light, the above base material preferably does not contain fine particles from the viewpoint of making the adhesive layer more easily cured. In the present specification, "fine particles" means particles having an average particle diameter of 100 μm or less measured by an optical microscope or the like.

[0102] Examples of the above fine particles include inorganic fine particles such as silica, alumina, and titanium oxide, and organic fine particles such as acrylic particles, silicone particles, and melamine particles.

[0103] The above-mentioned substrate is preferably a treated substrate obtained by treating the substrate. By the substrate being a treated substrate, it becomes easier to adjust the peak temperature of the thermal shrinkage stress of the adhesive film described later to a suitable range.

[0104] Examples of the treatment on the above-mentioned treated substrate include heat treatment, surface treatment, etc. More specifically, for example, annealing treatment, coating agent application, etc. are included, and among them, annealing treatment is preferable (that is, it is preferable that the above-mentioned substrate is a substrate subjected to annealing treatment (annealed substrate)). By the substrate being an annealed substrate, the residual stress of the substrate can be removed, and it becomes easier to adjust the peak temperature of the thermal shrinkage stress of the adhesive film described later to a suitable range. Note that the above-mentioned annealed substrate may be a substrate obtained by annealing a substrate such as an unannealed resin film, or a commercially available substrate whose substrate has been annealed may be used.

[0105] The upper limit of the thickness of the above-mentioned substrate is preferably 100 μm. By the thickness of the above-mentioned substrate being 100 μm or less, the adhesive film becomes excellent in ultraviolet transmittance. A more preferable upper limit of the thickness of the above-mentioned substrate is 80 μm, and an even more preferable upper limit is 60 μm. Also, the lower limit of the thickness of the above-mentioned substrate is preferably 5 μm. By the thickness of the above-mentioned substrate being 5 μm or more, the resulting adhesive film becomes firm and has better handleability. A more preferable lower limit of the thickness of the above-mentioned substrate is 7 μm, and an even more preferable lower limit is 10 μm.

[0106] The lower limit of the ratio of the thickness of the above-mentioned substrate to the thickness of the entire adhesive film of the present invention is preferably 5%. By the ratio of the thickness of the above-mentioned substrate being 5% or more, the resulting adhesive film becomes firm and has better handleability. A more preferable lower limit of the ratio of the thickness of the above-mentioned substrate is 10%, and an even more preferable lower limit is 15%. Also, the ratio of the thickness of the above substrate is preferably 80% or less with respect to the thickness of the entire adhesive film of the present invention. By the ratio of the thickness of the above substrate being 80% or less, the adhesive film becomes excellent in ultraviolet transmittance. A more preferable upper limit of the ratio of the thickness of the above substrate is 70%, and an even more preferable upper limit is 60%.

[0107] The adhesive film of the present invention may be a single-sided adhesive film having the above adhesive layer on one side of the above substrate, or a double-sided adhesive film having the above adhesive layer on both sides of the above substrate. Among them, from the viewpoint that a rigid support such as glass can be used to support a thin adherend with a thickness of 50 μm or less, the adhesive film of the present invention is preferably a double-sided adhesive film having the above adhesive layer on both sides of the above substrate.

[0108] The method for producing the adhesive film of the present invention is not particularly limited, and it can be produced by using a conventionally known method. Specifically, for example, first, the compound having the above imide bond and, if necessary, additives to be blended are mixed using a bead mill, ultrasonic dispersion, homogenizer, high-output disperser, roll mill, etc. to prepare an adhesive solution. Next, the obtained adhesive solution is coated on the release-treated surface of a release PET film and dried at 130°C for 10 minutes to produce a laminated film having an adhesive layer. Then, by laminating the laminated film on one surface of the substrate such that the adhesive layer faces, a single-sided adhesive film having a substrate and an adhesive layer on one surface of the substrate can be produced. Also, by using another adhesive solution prepared by the same method to produce a laminated film having another adhesive layer, and laminating another adhesive layer on the side of the above single-sided adhesive film that does not have the adhesive layer of the substrate, etc., a double-sided adhesive film having a substrate and adhesive layers on both surfaces of the substrate can be produced.

[0109] When manufacturing the adhesive film of the present invention, it is preferable to use the base material after drying treatment. By using the base material after drying treatment, the moisture content contained in the base material of the obtained adhesive film is reduced, so that foaming during the high-temperature processing step can be further suppressed, and peeling during the high-temperature processing step can be further prevented. Examples of the drying treatment conditions include leaving it to stand for 10 minutes in an environment of 130°C and 50% RH.

[0110] When manufacturing the adhesive film of the present invention, it is preferable to heat-treat the adhesive film obtained by laminating the base material and the adhesive layer. By heat-treating the adhesive film during the production of the adhesive film of the present invention, it becomes easier to adjust the peak temperature of the thermal shrinkage stress of the adhesive film within the range described later, and the obtained adhesive film becomes more excellent in heat resistance. The method of the heat treatment is not particularly limited, and examples thereof include a method of heating while adjusting the tension so that the dimensions of the adhesive film do not change.

[0111] The adhesive film of the present invention is subjected to thermomechanical analysis in which, after holding the adhesive film of the present invention at 25°C for 10 minutes, while raising the temperature from 25°C to 350°C at a heating rate of 10°C / min, the load when the change amount of the length of the adhesive film is maintained at 0 is detected as the thermal shrinkage stress. The lower limit of the temperature showing the maximum value of the thermal shrinkage stress of the adhesive film (hereinafter, may be simply referred to as "the peak temperature of the thermal shrinkage stress of the adhesive film") is 260°C. Since the peak temperature of the thermal shrinkage stress of the adhesive film of the present invention is 260°C or higher, the thermal shrinkage of the adhesive film during the high-temperature processing step can be suppressed, and peeling can be prevented. The preferable lower limit of the peak temperature of the thermal shrinkage stress of the adhesive film of the present invention is 270°C, and the more preferable lower limit is 280°C. Also, there is no upper limit to the peak temperature of the thermal shrinkage stress of the adhesive film of the present invention, and the higher the better, but about 500°C is the substantial upper limit.

[0112] The peak temperature of the thermal shrinkage stress of the above-mentioned adhesive film is measured by the following method. That is, first, a test piece is prepared by cutting the adhesive film into a size of 4 mm in width and 10 mm in length. Then, for the prepared test piece, in accordance with JIS K 7197:1991, using a thermomechanical analyzer (manufactured by Hitachi High-Tech Corporation, such as "TMA-SS7100"), after holding at 25°C for 10 minutes, while heating from 25°C to 350°C at a heating rate of 10°C / min, the load (thermal shrinkage stress) when the change amount of the length of the adhesive film is maintained at 0 is measured. From the spectrum of the thermal shrinkage stress of the obtained test piece, the temperature showing the maximum value is taken as the peak temperature of the thermal shrinkage stress of the adhesive film. In the case where there is no temperature showing the maximum value of the thermal shrinkage stress in the temperature range from 25°C to 350°C, the peak temperature of the thermal shrinkage stress of the adhesive film is taken as "above 350°C". Also, when there are two or more maximum values, the temperature showing the maximum value among them is taken as the peak temperature of the thermal shrinkage stress of the adhesive film.

[0113] The above-mentioned adhesive film at the peak temperature of the thermal shrinkage stress of the adhesive film of the present invention may be in an uncured state or a cured state. When using a cured adhesive film, as a method for curing the above-mentioned adhesive film, for example, a method of irradiating light with a wavelength of 405 nm by an ultra-high pressure mercury lamp at an illuminance of 80 mW / cm 2 for 300 seconds, a method of heating at 200°C for 30 minutes, etc. can be mentioned.

[0114] As a method for adjusting the peak temperature of the thermal shrinkage stress of the above-mentioned adhesive film, for example, a method of changing the composition of the above-mentioned adhesive layer, a method of changing the type and thickness of the above-mentioned base material, a method of using a treated base material obtained by treating the base material as the above-mentioned base material, a method of heat-treating the adhesive film during the production of the adhesive film as described above, etc. can be mentioned.

[0115] The adhesive film of the present invention preferably has a lower limit of the 5% weight loss temperature of 350°C. Since the 5% weight loss temperature of the adhesive film of the present invention is 350°C or higher, the adhesive film of the present invention becomes more excellent in heat resistance. A more preferable lower limit of the 5% weight loss temperature of the adhesive film of the present invention is 360°C, and an even more preferable lower limit is 370°C. In addition, there is no particular upper limit for the 5% weight loss temperature of the adhesive film of the present invention, but the substantial upper limit is about 500°C. The 5% weight loss temperature of the adhesive film of the present invention can be measured by differential thermal - thermogravimetric simultaneous measurement. Specifically, for example, it can be measured by the following methods. That is, a test piece obtained by cutting the adhesive film into a size of 25 mm in width × 50 mm in length is weighed into an aluminum pan, the aluminum pan is set in a differential thermal - thermogravimetric simultaneous measurement device, and when the temperature is raised from 30°C to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, the temperature at which the mass of the adhesive film decreases by 5% compared to before the temperature rise can be obtained as the 5% weight loss temperature respectively. As the above differential thermal - thermogravimetric simultaneous measurement device, for example, STA7200RV (manufactured by Hitachi High - Tech Science Corporation) etc. can be used. Note that the release PET film for protecting the adhesive layer is not laminated on the test piece.

[0116] The above - mentioned adhesive film at the 5% weight loss temperature of the adhesive film of the present invention may be in an uncured state or a cured state. When using a cured adhesive film, as a method for curing the above - mentioned adhesive film, for example, a method of irradiating light with a wavelength of 405 nm by an ultra - high - pressure mercury lamp at an illuminance of 80 mW / cm 2 for 300 seconds, a method of heating at 200°C for 30 minutes, etc. can be mentioned.

[0117] As a method for adjusting the 5% weight loss temperature of the above - mentioned adhesive film within the above - described range, for example, a method of changing the composition of the adhesive layer (for example, a method of containing an inorganic filler, etc.), a method of changing the type of the base material, etc. can be mentioned.

[0118] The haze of the adhesive film of the present invention is preferably greater than 3%. When the haze of the adhesive film of the present invention is greater than 3%, visibility is ensured, and the adhesive film can be more accurately attached to a support or an adherend. A more preferable lower limit of the haze of the adhesive film of the present invention is 8%, and an even more preferable lower limit is 9%. Also, a preferable upper limit of the haze of the adhesive film of the present invention is 60%. When the haze of the adhesive film of the present invention is 60% or less, the adhesive layer can be more sufficiently photocured. A more preferable upper limit of the haze of the adhesive film of the present invention is 50%. Note that the haze of the adhesive film of the present invention can be measured in accordance with JIS K7105 using a haze meter (for example, "NDH-2000" manufactured by Nippon Denshoku Industries Co., Ltd., etc.).

[0119] The above-mentioned adhesive film in the haze of the adhesive film of the present invention may be in an uncured state or a cured state. When using a cured adhesive film, as a method for curing the above-mentioned adhesive film, for example, a method of irradiating light with a wavelength of 405 nm by an ultra-high pressure mercury lamp at an illuminance of 80 mW / cm 2 for 300 seconds, a method of heating at 200 °C for 30 minutes, etc. may be mentioned.

[0120] As a method for adjusting the haze of the adhesive film of the present invention, a method of changing the composition of the above-mentioned adhesive layer (for example, a method of changing the type of release agent), a method of changing the thickness of the adhesive film, etc. may be mentioned.

[0121] The adhesive film of the present invention has high heat resistance and can suppress peeling during a high-temperature processing step. Therefore, it can be suitably used for protecting, adhering, and temporarily fixing an adherend that undergoes a high-temperature processing of 260 °C or higher, and among them, it is more suitably used for the manufacture of electronic components. Specifically, for example, during the processing of electronic components such as semiconductors, in order to facilitate the handling of the electronic components and prevent them from being damaged, the adhesive film of the present invention can be preferably used by temporarily fixing the electronic components to a support plate via the adhesive film of the present invention, or by attaching the adhesive film of the present invention to the electronic components for protection, etc. Examples of the high-temperature processing treatment include, for example, heat treatment of semiconductors.

[0122] The method for manufacturing an electronic component using the adhesive film of the present invention is also one of the present inventions. By using the above adhesive film, the peeling of the adhesive film due to the thermal shrinkage of the adhesive film during the high-temperature processing step of the electronic component can be prevented, so that the manufacturing efficiency and yield of the electronic component can be improved.

Effects of the Invention

[0123] According to the present invention, it is possible to provide an adhesive film having excellent heat resistance and capable of preventing peeling during a high-temperature processing step. Further, according to the present invention, it is possible to provide a method for manufacturing an electronic component using the adhesive film.

Modes for Carrying Out the Invention

[0124] Examples will be given below to explain the aspects of the present invention in more detail, but the present invention is not limited only to these examples.

[0125] (Synthesis of Polyimide Compound A) 250 mL of toluene was added to a 500 mL round-bottom flask containing a Teflon (registered trademark) stirrer. 39.9 g (0.075 mol) of diaminodimer (manufactured by Clariant, "Priamine 1075") and 39 g (0.0765 mol) of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride were added in this order. A Dean-Stark tube and a condenser were attached to the flask, and the resulting mixture was refluxed for 6 hours and then cooled to room temperature. A toluene solution of a resin (polyimide compound A) having a structural unit represented by the following formula (6), having no maleimide group, and having an imide skeleton as a repeating unit in the main chain was obtained. Regarding the obtained polyimide compound A, when measured by gel permeation chromatography (GPC, apparatus name: Acquity APC system (manufactured by Waters)) using THF as the eluent and HR-MB-M 6.0×150 mm (manufactured by Waters) as the column, the weight average molecular weight was 90,000.

[0126]

Chemical formula

[0127] (Synthesis of acrylic copolymer C) A reactor equipped with a thermometer, a stirrer, and a cooling pipe was prepared. 94 parts by mass of 2-ethylhexyl acrylate, 6 parts by mass of hydroxyethyl methacrylate, 0.01 part by mass of lauryl mercaptan, and 80 parts by mass of ethyl acetate were added into this reactor, and then the reactor was heated to start reflux. Subsequently, 0.01 part by mass of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added into the above reactor as a polymerization initiator, and polymerization was started under reflux. Next, 0.01 part by mass of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added also 1 hour and 2 hours after the start of polymerization, and further, 0.05 part by mass of t-hexyl peroxypivalate was added 4 hours after the start of polymerization to continue the polymerization reaction. And 8 hours after the start of polymerization, an ethyl acetate solution containing a functional group-containing acrylic polymer having a solid content of 55% by mass and a weight average molecular weight of 500,000 was obtained. To 100 parts by mass of the resin solid content of the obtained ethyl acetate solution containing the functional group-containing acrylic polymer, 3.5 parts by mass of 2-isocyanatoethyl methacrylate was added and reacted to obtain an acrylic copolymer C. The weight average molecular weight of the acrylic copolymer C was 550,000. Regarding the weight average molecular weight of the obtained acrylic copolymer C, it was measured by gel permeation chromatography (GPC, apparatus name: Acquity APC system (manufactured by Waters)) using THF as an eluent and HR-MB-M 6.0×150 mm (manufactured by Waters) as a column.

[0128] (Example 1) (Preparation of Adhesive Film) Each material described in Table 1 was added to 150 mL of toluene and mixed to prepare an adhesive solution 1. The bismaleimide compound B is a bismaleimide compound (manufactured by Designer Molecules, "BMI-689") represented by the following formula (7). The obtained adhesive solution 1 was applied onto the release-treated surface of a 50-μm thick PET film with one-sided release treatment (release PET film) using a doctor knife so that the dried thickness became as shown in Table 1, and the coating solution was dried by heating at 130°C for 10 minutes to produce a laminated film 1 having an adhesive layer 1. Further, an adhesive solution 2 having a composition different from that of the adhesive solution 1 (see Table 1) was prepared in the same manner. The obtained adhesive solution 2 was applied onto the release-treated surface of another 50-μm thick release PET film using a doctor knife so that the dried thickness became as shown in Table 1, and the coating solution was dried by heating at 130°C for 10 minutes to produce a laminated film 2 having an adhesive layer 2. An adhesive film having adhesive layers on both sides of the base material was obtained by superposing and laminating the adhesive layer 1 on one surface of the base material shown in Table 1 and the adhesive layer 2 on the other surface of the base material, respectively, and integrating them. In this Example and Comparative Examples, in the evaluation of "(peeling during high-temperature processing step)" described later, the adhesive layer to be bonded to the silicon wafer was the adhesive layer 2.

[0129]

Chemical formula

[0130] (Measurement of glass transition temperature of adhesive layer) After producing a test piece by cutting the obtained adhesive film into a size of 5 mm in width and 30 mm in length, for the produced test piece, dynamic viscoelasticity measurement was performed under the measurement conditions of tensile mode, heating rate of 10°C / min, measurement temperature of 0°C to 300°C, and frequency of 10 Hz using a dynamic viscoelasticity measuring device (manufactured by IT Measurement Control Co., Ltd., "DVA-200"). The temperature at which the maximum value of the measured loss tangent was obtained was taken as the glass transition temperature (°C) of the adhesive layers 1 and 2. When there were multiple maximum values of the measured loss tangent, the maximum value of the loss tangent on the lowest temperature side was taken as the glass transition temperature of the adhesive layer 1 and the adhesive layer 2. The results are shown in Table 1.

[0131] (Measurement of peak temperature of thermal shrinkage stress of adhesive film) After preparing a test piece by cutting the obtained adhesive film into a size of 4 mm in width and 10 mm in length, in accordance with JIS K 7197:1991, using a thermomechanical analyzer (manufactured by Hitachi High-Tech Corporation, "TMA-SS7100"), after holding at 25°C for 10 minutes, while raising the temperature from 25°C to 350°C at a heating rate of 10°C / min, thermomechanical analysis (TMA) was performed to detect the load when the change amount of the sample length was maintained at 0 as the thermal shrinkage stress, and the thermal shrinkage stress of the test piece was measured. From the spectrum of the thermal shrinkage stress of the obtained test piece, the temperature showing the maximum value was taken as the peak temperature (°C) of the thermal shrinkage stress of the adhesive film. In the case where there is no temperature showing the maximum value of the thermal shrinkage stress in the temperature range from 25°C to 350°C, the peak temperature of the thermal shrinkage stress of the adhesive film was taken as "above 350". Also, when there are two or more maximum values, the temperature showing the maximum value among them was taken as the peak temperature of the thermal shrinkage stress of the adhesive film. The results are shown in Table 1.

[0132] (Measurement of 1% weight loss temperature, 5% weight loss temperature, and 10% weight loss temperature of the adhesive film) A test piece obtained by cutting the obtained adhesive film into a size of 25 mm in width and 50 mm in length was weighed into an aluminum pan, and the aluminum pan was set in a differential thermal-thermogravimetric simultaneous measurement device (manufactured by Hitachi High-Tech Science Corporation, "STA7200RV"). When the temperature was raised from 30°C to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, the temperatures at which the mass of the adhesive film decreased by 1%, 5%, and 10% compared to before the temperature rise were obtained as the 1% weight loss temperature, 5% weight loss temperature, and 10% weight loss temperature, respectively. Note that the test piece is assumed not to have a release PET film laminated to protect the adhesive layer. The results are shown in Table 1.

[0133] (Measurement of haze of the adhesive film) For the obtained adhesive film, in accordance with JIS K7105, using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., "NDH-2000"), the haze (%) of the adhesive film was measured from the adhesive layer 1 side. The results are shown in Table 1.

[0134] (Examples 2 to 11, Comparative Examples 1 to 4) An adhesive film was produced and measured in the same manner as in Example 1, except that the compositions and thicknesses of the adhesive layer 1 and the adhesive layer 2, and the type and thickness of the base material were made to be those shown in Tables 1 and 2. The results are shown in Tables 1 and 2.

[0135] (Example 12) An adhesive film was produced in the same manner as in Example 1, except that the compositions and thicknesses of the adhesive layer 1 and the adhesive layer 2, and the type and thickness of the base material were made to be those shown in Table 1. Using a thermomechanical analyzer (manufactured by Hitachi High-Tech Corporation, "TMA-SS7100"), the produced adhesive film was held at 25°C for 10 minutes while adjusting the tension so that the dimensions of the adhesive film did not change, and then a heat treatment was performed in which it was heated from 25°C to 350°C at a heating rate of 10°C / min to obtain the adhesive film of Example 12. For various measurements, they were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0136] The resins contained in the base materials shown in Tables 1 and 2, and the abbreviations of the types of the base materials are as follows. PEEK: Polyetheretherketone PI: Polyimide PA: Polyamide PEN: Polyethylene naphthalate PET: Polyethylene terephthalate PEEK-containing base material B6: EXPEEK (manufactured by Kuraray Co., Ltd., no annealing treatment on the base material surface) PEEK-containing base material B7: EXPEEK (manufactured by Kuraray Co., Ltd., annealing treatment on the base material surface) PI-containing base material B1: Kapton (manufactured by Toray DuPont Co., Ltd., no annealing treatment on the base material surface) PI-containing base material B2: MORDOHA (manufactured by Mortec Co., Ltd., no annealing treatment on the base material surface) PI-containing base material B3: Upilex 25U (manufactured by UBE Industries, Ltd., no annealing treatment on the base material surface) PA-containing base material: Uniamide EX (manufactured by Unitika Ltd., no annealing treatment on the base material surface) The PEN contains a base material: Teonex Q83C (manufactured by Teijin Limited, no annealing treatment on the surface of the base material) The PET-containing base material B4: LS-PET (manufactured by Toyo Cloth Co., Ltd., no annealing treatment on the surface of the base material) The PET-containing base material B5: Lumirror (manufactured by Toray Industries, Inc., no annealing treatment on the surface of the base material) Regarding the annealing treatment on the surface of the PEEK-containing base material B7, it was carried out by heating the non-annealed PEEK-containing base material B6 at 280°C for 1 minute.

[0137] <Evaluation> The adhesive films obtained in the examples and comparative examples were evaluated by the following method. The results are shown in Tables 1 and 2.

[0138] (Heat resistance) (1) Heat resistance of the adhesive layer In the above-mentioned "(Measurement of the glass transition temperature of the adhesive layer)", when the glass transition temperature of the obtained adhesive layer 2 was 0°C or higher, it was evaluated as "○", and when it was less than 0°C, it was evaluated as "×" for the heat resistance of the adhesive layer.

[0139] (2) Peeling during the high-temperature processing step The obtained adhesive film was cut into a size of 5 cm square, and the cut adhesive film was laminated on a silicon wafer with a thickness of 725 μm using a roller with a weight of 2 kg to bond the adhesive layer 2, and then left standing for 10 minutes in an environment of 25°C and 60% RH to prepare a measurement sample. For the prepared measurement sample, after peeling off the release PET film that protects the adhesive layer 1 of the adhesive film to expose the adhesive layer 1, the laminate was placed on a hot plate set at 280°C with the silicon wafer side in contact with the hot plate and heated for 15 minutes. After the measurement sample was air-cooled, the adhesive film in the measurement sample was visually observed using a ruler. When any one side of the adhesive film shrank by less than 0.15 cm, it was rated as "◎"; when at least one side of the adhesive film shrank by 0.15 cm or more and less than 0.2 cm, and any one side of the adhesive film shrank by less than 0.2 cm, it was rated as "○"; when at least one side of the adhesive film shrank by 0.2 cm or more, it was rated as "×". The peeling during the high-temperature processing step was evaluated.

[0140]

Table 1

[0141]

Table 2

Industrial Applicability

[0142] According to the present invention, it is possible to provide an adhesive film having excellent heat resistance and capable of preventing peeling during a high-temperature processing step. Further, according to the present invention, it is possible to provide a method for manufacturing an electronic component using the adhesive film.

Claims

1. An adhesive film having an adhesive layer and a substrate, The adhesive film is held at 25° C. for 10 minutes, and then heated from 25° C. to 350° C. at a heating rate of 10° C. / min. The load when the change in length of the adhesive film is kept at 0 is detected as the heat shrinkage stress. In this thermomechanical analysis, the temperature at which the heat shrinkage stress of the adhesive film shows a maximum value is 260° C. or higher; The adhesive layer has a glass transition temperature of 0° C. or higher. An adhesive film characterized by:

2. The adhesive film according to claim 1 , wherein the adhesive layer contains a compound having an imide bond.

3. The adhesive film according to claim 1 or 2, wherein the adhesive layer contains a polymerization initiator.

4. The adhesive film according to claim 1 or 2, wherein the adhesive layer contains an ultraviolet absorbing agent.

5. 3. The adhesive film according to claim 1, wherein the substrate contains a resin having in its main chain a repeating unit containing at least one type selected from the group consisting of an ether bond, a ketone group, and an imide bond.

6. 3. The adhesive film according to claim 1, wherein the substrate does not contain fine particles.

7. 3. The adhesive film according to claim 1, wherein the thickness of the substrate is from 5 μm to 100 μm.

8. 3. The adhesive film according to claim 1, wherein the ratio of the thickness of the substrate to the total thickness of the adhesive film is from 5% to 80%.

9. 3. The adhesive film according to claim 1, wherein the adhesive film has a 5% weight loss temperature of 350° C. or higher.

10. 3. The adhesive film according to claim 1, wherein the adhesive film has a haze of more than 3%.

11. 3. The adhesive film according to claim 1, which is used for the production of electronic components.

12. A method for producing an electronic part, which uses the adhesive film according to claim 1 or 2.

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