JP7719632B2 - Pressure-sensitive adhesive composition, pressure-sensitive adhesive tape, and method for manufacturing semiconductor device - Google Patents

Description

The present invention relates to a pressure-sensitive adhesive composition that forms a pressure-sensitive adhesive layer that can be easily peeled off while reducing contamination of the adherend, even when the composition is attached to a resin-based adherend and subjected to a process involving high-temperature heating. The present invention also relates to a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition, and a method for manufacturing a semiconductor device using the pressure-sensitive adhesive tape.

In the manufacturing process of semiconductor chips, adhesive tape is used to facilitate handling of wafers and semiconductor chips during processing and to prevent breakage. For example, when a thick-film wafer cut from a high-purity silicon single crystal is ground to a specified thickness to produce a thin-film wafer, adhesive tape is attached to the thick-film wafer before grinding. Also, wafers, semiconductor chips, and other adherends are sometimes fixed to a support plate via adhesive tape, and the adherends fixed to the support plate are then processed.

Such adhesive tapes are required to have high enough adhesion to firmly secure adherends such as wafers and semiconductor chips during processing, as well as the ability to be peeled off without damaging the adherends after processing is completed (hereinafter referred to as "high adhesion and easy peeling"). Patent Document 1 discloses an adhesive tape that achieves high adhesion and easy peeling, using a photocurable adhesive that hardens and reduces adhesive strength when exposed to light such as ultraviolet light. The use of a photocurable adhesive as the adhesive allows for secure fixation of adherends during processing, while also allowing for easy peeling by exposure to ultraviolet light. Patent Document 2 also discloses a removable adhesive in which a non-silicone adhesive contains a silicone-based graft copolymer with functional groups capable of crosslinking with the adhesive's base polymer. Patent Document 2 describes improved removability achieved by using a silicone-based graft copolymer, which has excellent inhibitory effects on the increase in adhesive strength.

Japanese Patent Application Publication No. 5-32946 Japanese Patent Application Publication No. 2-123182

To achieve high adhesion and easy peelability, a method has been used, for example, as described in Patent Document 2, in which a release agent such as a silicone compound is blended into the adhesive layer to reduce the increase in adhesive strength (adhesion enhancement) over time. However, in recent years, there has been an increase in the practice of subjecting adhesive tapes attached to adherends to treatments involving heating at higher temperatures than conventional methods, specifically at temperatures as high as 200°C or higher. This has created the problem that the effect of reducing adhesion enhancement is not fully achieved when processes involving heating at such high temperatures are carried out. In particular, in recent years, the use of resin-based adherends made from polyimide, epoxy resin, etc., has become more common in addition to inorganic adherends such as silicon wafers and glass. Compared to inorganic adherends, resin-based adherends are more susceptible to adhesion enhancement. Another problem has arisen in processes involving heating at high temperatures, in that the release agent is more likely to bleed out of the adhesive layer, causing contamination of the adherend.

The present invention aims to provide a pressure-sensitive adhesive composition that forms a pressure-sensitive adhesive layer that can be easily peeled off while reducing contamination of the adherend, even when the composition is attached to a resin-based adherend and subjected to a process involving high-temperature heating. The present invention also aims to provide a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition, and a method for manufacturing a semiconductor device using the pressure-sensitive adhesive tape.

The present invention is a pressure-sensitive adhesive composition containing an adhesive polymer, silicone oil, and a silicone graft copolymer having structural units derived from a silicone macromonomer. The present invention is described in detail below.

The inventors investigated the use of a pressure-sensitive adhesive composition containing an adhesive polymer, in combination with a silicone oil and a silicone graft copolymer having structural units derived from a silicone macromonomer, as a release agent. The inventors discovered that such a pressure-sensitive adhesive composition can form a pressure-sensitive adhesive layer that is easily peeled off while reducing contamination of the adherend, even when subjected to a process involving high-temperature heating in a state where it is attached to a resin-based adherend, and thus completed the present invention.

The pressure-sensitive adhesive composition of the present invention contains a pressure-sensitive adhesive polymer, silicone oil, and a silicone graft copolymer having structural units derived from a silicone macromonomer.
That is, the pressure-sensitive adhesive composition of the present invention uses, as a release agent, a silicone oil in combination with a silicone graft copolymer having structural units derived from a silicone macromonomer.
When the pressure-sensitive adhesive composition of the present invention contains the silicone graft copolymer, the silicone graft copolymer undergoes molecular migration and accumulates on the surface of the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition, making the surface of the pressure-sensitive adhesive layer hydrophobic.Furthermore, the silicone oil is more likely to accumulate on the surface of the pressure-sensitive adhesive layer that has become hydrophobic in this way, and the accumulation of the silicone oil makes the surface of the pressure-sensitive adhesive layer even more hydrophobic.As a result, the pressure-sensitive adhesive layer and the adherend are less likely to interact with each other, so that even when the pressure-sensitive adhesive layer is attached to a resin-based adherend and undergoes a process involving high-temperature heating, the adhesion increase can be reduced, the pressure-sensitive adhesive layer can be easily peeled off, and adhesive residue can be reduced.

The adhesive polymer preferably has a polar functional group.
When the adhesive polymer has the polar functional group, and the silicone oil and/or the silicone graft copolymer have a functional group that can be crosslinked with the adhesive polymer, the silicone oil and/or the silicone graft copolymer are bonded to the adhesive polymer via a crosslinking agent.This can reduce the contamination of the adherend caused by the silicone oil and/or the silicone graft copolymer bleeding out.
Furthermore, by bonding the silicone graft copolymer to the adhesive polymer via the crosslinking agent, the crosslink density on the surface of the adhesive layer increases, the elastic modulus increases, and the adhesive strength decreases, which makes it possible to further reduce adhesion enhancement even when the adhesive layer is attached to a resin-based adherend and undergoes a process involving high-temperature heating, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue.
The polar functional group is not particularly limited, and examples thereof include a carboxyl group, a hydroxyl group, a glycidyl group, an amide group, a nitrile group, etc. Among these, a carboxyl group and a hydroxyl group are preferred, and a carboxyl group is more preferred.

The adhesive polymer may have a radically polymerizable unsaturated bond within the molecule. When the adhesive polymer has the radically polymerizable unsaturated bond, the adhesive layer hardens in the presence of a polymerization initiator upon stimulation by heat, light, or the like, increasing its elastic modulus and decreasing its adhesive strength. This reduces increased adhesion, even when the adhesive layer is subjected to a process involving high-temperature heating while attached to a resin-based adherend, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue. Furthermore, when the adhesive polymer has the radically polymerizable unsaturated bond, the polarity of the crosslinking points is lower than when the adhesive polymer has other polymerizable functional groups, increasing the crosslink density when the adhesive layer hardens, thereby further increasing the elastic modulus of the adhesive layer. This reduces increased adhesion, even when the adhesive layer is subjected to a process involving high-temperature heating while attached to a resin-based adherend, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue.

The method for introducing the radically polymerizable unsaturated bond into the adhesive polymer is not particularly limited, and examples include a method of using a monomer having a radically polymerizable unsaturated bond when synthesizing the adhesive polymer, and a method of reacting a compound having a radically polymerizable unsaturated bond with a precursor polymer of the adhesive polymer.

The weight-average molecular weight of the adhesive polymer is not particularly limited, but a preferred lower limit is 500,000 and a preferred upper limit is 1,500,000. If the weight-average molecular weight is within the above range, the flexibility of the adhesive layer will be increased and adhesion to the adherend will be improved, resulting in a higher initial adhesive strength. A more preferred lower limit of the weight-average molecular weight is 800,000 and a more preferred upper limit is 1,200,000. To adjust the weight-average molecular weight to fall within the above range, for example, the composition, polymerization method, polymerization conditions, etc. of the adhesive polymer may be adjusted.

The weight-average molecular weight can be measured by the following method. A solution of the adhesive polymer is filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The resulting filtrate is fed to a gel permeation chromatograph (e.g., Waters, 2690 Separations Model) and subjected to GPC measurement at a sample flow rate of 1 milliliter/min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the adhesive polymer is measured to determine the weight-average molecular weight. For example, a GPC KF-806L (Showa Denko KK) is used as the column, and a differential refractometer is used as the detector.

Specific examples of the above-mentioned adhesive polymers include acrylic polymers, silicone polymers, urethane polymers, and rubber polymers. Among these, acrylic polymers are preferred because they have excellent heat resistance and weather resistance, are suitable for applications that involve processes involving high-temperature heating, are applicable to a wide range of adherends, and furthermore, their glass transition temperatures are easily adjustable.

When the adhesive polymer is the acrylic polymer, in order to have the polar functional group, the acrylic polymer preferably has a constituent unit derived from a monomer having the polar functional group.
When the polar functional group is a carboxyl group, examples of monomers having a carboxyl group include (meth)acrylic acid. When the polar functional group is a hydroxyl group, examples of monomers having a hydroxyl group include (meth)acrylic acid esters having a hydroxyl group, such as 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate. When the polar functional group is a glycidyl group, examples of monomers having a glycidyl group include glycidyl (meth)acrylate. When the polar functional group is an amide group, examples of monomers having an amide group include hydroxyethyl acrylamide, isopropyl acrylamide, and dimethylaminopropyl acrylamide. When the polar functional group is a nitrile group, examples of monomers having a nitrile group include acrylonitrile. These monomers having a polar functional group may be used alone or in combination of two or more.

When the acrylic polymer contains a structural unit derived from the monomer having a carboxyl group, its content is not particularly limited, but a preferred lower limit is 0.1% by weight and a preferred upper limit is 10% by weight. If the content is 0.1% by weight or more, the acrylic polymer can be sufficiently bonded to the silicone oil and/or the silicone graft copolymer via the crosslinking agent, thereby further reducing contamination of the adherend. If the content is 10% by weight or less, the pressure-sensitive adhesive layer does not become too hard, and adhesive residue can be suppressed.

When the acrylic polymer contains a structural unit derived from the monomer having a hydroxyl group, its content is not particularly limited, but a preferred lower limit is 0.1% by weight and a preferred upper limit is 30% by weight. If the content is 0.1% by weight or more, the acrylic polymer can be sufficiently bonded to the silicone oil and/or the silicone graft copolymer via the crosslinking agent, thereby further reducing contamination of the adherend. If the content is 30% by weight or less, the pressure-sensitive adhesive layer can maintain high adhesion even at high temperatures.

The acrylic polymer may contain, in addition to the structural units derived from the monomer having a polar functional group, structural units derived from other radically polymerizable monomers. Examples of such other radically polymerizable monomers include (meth)acrylic acid esters and vinyl compounds.

The (meth)acrylic acid ester is not particularly limited, and examples thereof include (meth)acrylic acid alkyl esters. Examples of the (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isomyristyl (meth)acrylate, and stearyl (meth)acrylate. Examples of the (meth)acrylic acid ester include cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and polypropylene glycol mono(meth)acrylate. These (meth)acrylic acid esters may be used alone or in combination of two or more.

The vinyl compound is not particularly limited, and examples include styrene and vinyl acetate. These vinyl compounds may be used alone or in combination of two or more.

When the adhesive polymer is an acrylic polymer, in order to have the radically polymerizable unsaturated bond, it is preferable to react a compound having a functional group reactive with the polar functional group and a radically polymerizable unsaturated bond (hereinafter also referred to as a "functional group-containing unsaturated compound") with the polar functional group present in the acrylic polymer. Note that if all of the polar functional groups present in the acrylic polymer react with the functional group-containing unsaturated compound, the acrylic polymer will no longer have a polar functional group. Therefore, when preparing an acrylic polymer having both polar functional groups and radically polymerizable unsaturated bonds, it is necessary to adjust the reactivity by appropriately adjusting the type of functional group-containing unsaturated compound, reaction conditions, etc.

The functional group-containing unsaturated compound is not particularly limited and can be appropriately selected depending on the polar functional group present in the acrylic polymer. When the polar functional group present in the acrylic polymer is a carboxyl group, a compound having an epoxy group and a radically polymerizable unsaturated bond, a compound having an isocyanate group and a radically polymerizable unsaturated bond, etc. are used. When the polar functional group present in the acrylic polymer is a hydroxyl group, a compound having an isocyanate group and a radically polymerizable unsaturated bond, etc. are used. When the polar functional group present in the acrylic polymer is an epoxy group, a compound having a carboxyl group and a radically polymerizable unsaturated bond, a compound having an amide group and a radically polymerizable unsaturated bond, etc. are used. When the polar functional group present in the acrylic polymer is an amino group, a compound having an epoxy group and a radically polymerizable unsaturated bond, etc. are used.

The acrylic polymer is obtained by copolymerizing a monomer mixture. To obtain the acrylic polymer by copolymerizing the monomer mixture, the monomer mixture is subjected to a radical reaction in the presence of a polymerization initiator. The method for radically reacting the monomer mixture, i.e., the polymerization method, can be a conventionally known method, such as solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, or bulk polymerization. Examples of reaction methods for radically reacting the monomer mixture include living radical polymerization and free radical polymerization.

The acrylic polymer is preferably an acrylic polymer obtained by living radical polymerization (hereinafter also referred to as "living radically polymerized acrylic polymer"). Living radical polymerization is a type of polymerization in which molecular chains grow without being hindered by side reactions such as termination reactions or chain transfer reactions. In living radical polymerization, the reaction proceeds without deactivating the growing terminal radicals or generating new radical species during the reaction. During the reaction, all molecular chains polymerize while reacting uniformly with monomers, and the composition of all molecular chains approaches uniformity. Therefore, living radical polymerization produces polymers with more uniform molecular weight and composition than free radical polymerization, and suppresses the generation of low-molecular-weight components, thereby increasing the cohesive strength of the adhesive layer formed from the adhesive composition. As a result, initial adhesive strength is increased, and even when the composition is subjected to a process involving high-temperature heating while attached to a resin-based adherend, increased adhesion can be further reduced, allowing the adhesive layer to be more easily peeled and reducing adhesive residue.

On the other hand, in free radical polymerization, radical species are continuously generated during the reaction and add to the monomer, causing the polymerization to proceed. Therefore, in free radical polymerization, molecular chains are produced in which the growing terminal radicals are deactivated during the reaction, and molecular chains are grown by newly generated radical species during the reaction. Therefore, compared to living radical polymerization, free radical polymerization results in a non-uniform polymer composition, and also includes polymers with relatively low molecular weights.

Various polymerization methods may be used in the above-mentioned living radical polymerization. For example, an iron, ruthenium, or copper catalyst and a halogen-based initiator may be used (ATRP), TEMPO may be used, or an organotellurium polymerization initiator may be used. Among these, the use of an organotellurium polymerization initiator is preferable. Unlike other living radical polymerizations, living radical polymerization using an organotellurium polymerization initiator can polymerize radical polymerizable monomers having polar functional groups such as hydroxyl groups or carboxyl groups using the same initiator without protecting any of them, thereby producing polymers with uniform molecular weight and composition. This allows for easy copolymerization of radical polymerizable monomers having polar functional groups.

The molecular weight distribution (Mw/Mn) of the living radical polymerization acrylic polymer is not particularly limited, but a preferred lower limit is 1.05 and a preferred upper limit is 2.5. When the molecular weight distribution (Mw/Mn) is within the above range, the cohesive strength of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is high. As a result, the initial adhesive strength is high, and even when the pressure-sensitive adhesive composition undergoes a process involving high-temperature heating while attached to a resin-based adherend, increased adhesion can be further reduced, allowing the pressure-sensitive adhesive layer to be more easily peeled off and reducing adhesive residue. A more preferred lower limit of the molecular weight distribution (Mw/Mn) is 1.1 and a more preferred upper limit is 2.0.

The acrylic polymer may be an acrylic polymer obtained by constant-temperature free radical polymerization (hereinafter also referred to as "constant-temperature free-radical polymerized acrylic polymer"). As described above, free radical polymerization results in a less uniform polymer composition than living radical polymerization, and also includes polymers with relatively low molecular weights. However, among free radical polymerizations, constant-temperature free radical polymerization can suppress the generation of low-molecular-weight components compared to boiling-point free radical polymerization, thereby increasing the cohesive strength of the adhesive layer formed from the adhesive composition. As a result, the initial adhesive strength is increased, and even when the adhesive layer is subjected to a process involving high-temperature heating while attached to a resin-based adherend, increased adhesion can be further reduced, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue.

A dispersion stabilizer may be used when the monomer mixture is subjected to a radical reaction. Examples of such dispersion stabilizers include polyvinylpyrrolidone, polyvinyl alcohol, methyl cellulose, ethyl cellulose, poly(meth)acrylic acid, poly(meth)acrylic acid esters, and polyethylene glycol. When a polymerization solvent is used when the monomer mixture is subjected to a radical reaction, the polymerization solvent is not particularly limited. Examples of the polymerization solvent that can be used include nonpolar solvents such as hexane, cyclohexane, octane, toluene, and xylene, and highly polar solvents such as water, methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, and N,N-dimethylformamide. These polymerization solvents may be used alone or in combination. From the standpoint of polymerization rate, the polymerization temperature is preferably 0 to 110°C.

The above-mentioned silicone oil is an oily resin made of a linear polymer with a siloxane bond as the main skeleton, and typically refers to one with a weight-average molecular weight of 500 or more and 150,000 or less. The above-mentioned silicone oil also includes modified silicone oil. Examples of the above-mentioned modified silicone oil include epoxy-modified silicone, amino-modified silicone, carboxy-modified silicone, carbinol-modified silicone, mercapto-modified silicone, phenol-modified silicone, (meth)acrylic-modified silicone, polyether-modified silicone, methylstyryl-modified silicone, alkyl-modified silicone, and fluorine-modified silicone.

The weight-average molecular weight of the silicone oil is not particularly limited, but a preferred lower limit is 500 and a preferred upper limit is 150,000, with a more preferred lower limit of 1,000 and a more preferred upper limit of 100,000. When the weight-average molecular weight of the silicone oil is 1,000 or more, contamination of the adherend due to bleed-out of the silicone oil can be further reduced. When the weight-average molecular weight of the silicone oil is 100,000 or less, the silicone oil is more likely to move within the adhesive layer formed by the adhesive composition and to collect on the surface of the adhesive layer. This can further reduce adhesion enhancement, even when the adhesive layer is subjected to a process involving high-temperature heating while attached to a resin-based adherend, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue. A more preferred lower limit of the weight-average molecular weight of the silicone oil is 2,000 and an even more preferred upper limit is 50,000, with an even more preferred lower limit of 3,000 and an even more preferred upper limit of 10,000.

The silicone oil preferably has a functional group capable of crosslinking with the adhesive polymer. When the silicone oil has a functional group capable of crosslinking with the adhesive polymer, the silicone oil bonds to the adhesive polymer via a crosslinking agent. This further reduces contamination of the adherend due to bleeding out of the silicone oil. The functional group capable of crosslinking with the adhesive polymer is not particularly limited and is determined appropriately according to the functional group present in the adhesive polymer. Examples include amino groups, carboxyl groups, hydroxyl groups, epoxy groups, mercapto groups, and (meth)acrylic groups. Of these, carboxyl groups, hydroxyl groups, epoxy groups, and (meth)acrylic groups are preferred, with epoxy groups being more preferred.

The content of the silicone oil is not particularly limited, but a preferred lower limit is 0.1 parts by weight and a preferred upper limit is 15 parts by weight per 100 parts by weight of the adhesive polymer. If the content is 0.1 parts by weight or more, increased adhesion can be further reduced even when the adhesive is attached to a resin-based adherend and undergoes a process involving high-temperature heating, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue. If the content is 15 parts by weight or less, contamination of the adherend due to bleeding out of the silicone oil can be further reduced. A more preferred lower limit of the content is 1 part by weight and a more preferred upper limit is 10 parts by weight, an even more preferred lower limit is 4 parts by weight, and an even more preferred upper limit is 6 parts by weight.

The silicone graft copolymer is a copolymer having a graft chain containing a siloxane bond. The silicone graft copolymer has structural units derived from a silicone macromonomer. The silicone macromonomer is not particularly limited as long as it is a monomer having a siloxane bond-containing group, and examples include acrylic silicone macromonomers and styrene silicone macromonomers. Among these, acrylic silicone macromonomers are preferred because of their excellent heat resistance and weather resistance, and acrylic silicone macromonomers having the structure shown in general formula (1) or (2) below are more preferred.

Here, R represents a (meth)acryloyl group-containing functional group, and X and Y each independently represent an integer of 0 or 1 or greater. Examples of R include a (meth)acryloyl group. There are no particular upper limits for X and Y, but X and Y are typically 5,000 or less, preferably 500 or less, and more preferably 200 or less.

The weight-average molecular weight of the silicone macromonomer is not particularly limited, but a preferred lower limit is 500 and a preferred upper limit is 50,000. If the weight-average molecular weight is within the above range, the hydrophobic surface layer formed by the silicone graft copolymer will be thicker, which will further reduce increased adhesion even when the adhesive is attached to a resin-based adherend and undergoes a process involving high-temperature heating, allowing the pressure-sensitive adhesive layer to be more easily peeled off and reducing adhesive residue. A more preferred lower limit of the weight-average molecular weight is 1,000 and a more preferred upper limit is 20,000.

The content of the structural units derived from the silicone macromonomer is not particularly limited, but a preferred lower limit in the silicone graft copolymer is 1 wt %, and a preferred upper limit is 90 wt %. If the content is within the above range, enhanced adhesion can be further reduced even when the adhesive is attached to a resin-based adherend and undergoes a process involving high-temperature heating, allowing the pressure-sensitive adhesive layer to be more easily peeled off and reducing adhesive residue. A more preferred lower limit for the content is 5 wt %, a more preferred upper limit is 80 wt %, an even more preferred lower limit is 10 wt %, and an even more preferred upper limit is 60 wt %.

The silicone graft copolymer preferably has a functional group crosslinkable with the adhesive polymer. When the silicone graft copolymer has a functional group crosslinkable with the adhesive polymer, the silicone graft copolymer bonds to the adhesive polymer via a crosslinking agent. This further reduces contamination of the adherend due to bleeding out of the silicone graft copolymer. Furthermore, when the silicone graft copolymer bonds to the adhesive polymer via a crosslinking agent, the crosslinking density of the surface of the adhesive layer increases, the elastic modulus increases, and the adhesive strength decreases. This further reduces adhesion enhancement even when the adhesive layer is subjected to a process involving high-temperature heating while attached to a resin-based adherend, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue.
The functional group capable of crosslinking with the adhesive polymer is not particularly limited and is appropriately determined according to the functional group present in the adhesive polymer, and examples thereof include an isocyanate group, a carboxyl group, a hydroxyl group, a glycidyl group, an amide group, a nitrile group, etc. Among these, an isocyanate group, a carboxyl group, and a hydroxyl group are preferred, and a carboxyl group and a hydroxyl group are more preferred.

The functional group capable of crosslinking with the adhesive polymer may be protected by a protecting group in order to prevent unintended reactions. The protecting group is not particularly limited, but is preferably a protecting group that is released by heat, and specific examples thereof include a pyrazole group, a phenol group, an oxime group, a lactam group, and a vinyl ether group.
The protecting group is appropriately determined depending on the functional group crosslinkable with the adhesive polymer, and examples of the protecting group for a carboxyl group include a vinyl ether group, etc., and examples of the protecting group for an isocyanate group include a pyrazole group, etc. Furthermore, examples of the protecting group for a hydroxyl group include a silyl group, an acetyl group, an acetal-based protecting group, a benzyl group, an allyl group, a pyrazole group, a phenol group, an oxime group, a lactam group, etc.

When the silicone-based graft copolymer has a functional group capable of crosslinking with the adhesive polymer, the functional group capable of crosslinking with the adhesive polymer may be present in the graft chain of the silicone-based graft copolymer, in the main chain, or in both the graft chain and the main chain.

In order for the silicone graft copolymer to have a functional group crosslinkable with the adhesive polymer, it preferably has a structural unit derived from a monomer having a functional group crosslinkable with the adhesive polymer. The monomer having a functional group crosslinkable with the adhesive polymer is not particularly limited, and a monomer similar to the monomer having a polar functional group, as described above, used in the case of an acrylic polymer as the adhesive polymer can be used. Furthermore, when the functional group crosslinkable with the adhesive polymer is an isocyanate group, the isocyanate group may be protected with a protecting group. In this case, examples of monomers having a protected isocyanate group include 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl (meth)acrylate and 2-[0-(1'-methylpropylideneamino)carboxyamino]ethyl methacrylate.

The content of the structural unit derived from a monomer having a functional group crosslinkable with the adhesive polymer is not particularly limited, but a preferred lower limit in the silicone graft copolymer is 0.1 wt %, and a preferred upper limit is 30 wt %. If the content is within the above range, the silicone graft copolymer is sufficiently bonded to the adhesive polymer, while the adhesive polymers themselves can also form a sufficiently crosslinked structure. This makes it possible to further reduce increased adhesion even when the adhesive tape is subjected to a process involving high-temperature heating while attached to a resin-based adherend, allowing the adhesive tape to be more easily peeled off and reducing adhesive residue. A more preferred lower limit of the content is 1 wt %, a more preferred upper limit is 20 wt %, and an even more preferred upper limit is 10 wt %.

Furthermore, the functional group crosslinkable with the adhesive polymer may be a radically polymerizable unsaturated bond. In this case, in order for the silicone-based graft copolymer to have the radically polymerizable unsaturated bond, it is preferable to react the functional group present in the silicone-based graft copolymer with a compound having a functional group reactive with the functional group and a radically polymerizable unsaturated bond. Such a compound is not particularly limited, and compounds similar to the functional group-containing unsaturated compounds used in the case of acrylic polymers as the adhesive polymer can be used.

The silicone graft copolymer may further contain structural units derived from (meth)acrylic acid esters, vinyl compounds, other monomers having polar functional groups, and the like, in addition to structural units derived from the silicone macromonomers and the monomers having functional groups crosslinkable with the adhesive polymer. The (meth)acrylic acid esters and vinyl compounds are not particularly limited, and monomers similar to the (meth)acrylic acid esters described above used in the case of acrylic polymers as the adhesive polymer can be used. Of these, 2-ethylhexyl acrylate is preferred because it can impart appropriate adhesive strength.

The weight-average molecular weight of the silicone graft copolymer is not particularly limited, but a preferred lower limit is 5,000 and a preferred upper limit is 400,000. If the weight-average molecular weight is 5,000 or higher, the silicone graft copolymer is more easily incorporated into the crosslinked structure of the adhesive polymer, thereby further reducing contamination of the adherend. If the weight-average molecular weight is 400,000 or lower, the silicone graft copolymer is more easily mobile within the adhesive layer formed by the adhesive composition and more likely to collect on the surface of the adhesive layer. This makes it possible to further reduce increased adhesion, even when the adhesive layer is subjected to a process involving high-temperature heating while attached to a resin-based adherend, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue. A more preferred upper limit of the weight-average molecular weight is 300,000, an even more preferred upper limit is 250,000, and an especially preferred upper limit is 200,000, and is typically 10,000 or higher.

The method for producing the silicone graft copolymer is not particularly limited, and it can be obtained by copolymerizing a monomer mixture. The method for copolymerizing the monomer mixture to obtain the silicone graft copolymer is not particularly limited, and the same method as for the acrylic polymer used as the adhesive polymer can be used.

The content of the silicone-based graft copolymer is not particularly limited, but a preferred lower limit is 1 part by weight and a preferred upper limit is 15 parts by weight per 100 parts by weight of the adhesive polymer. If the content is 1 part by weight or more, increased adhesion can be further reduced even when the adhesive is attached to a resin-based adherend and subjected to a process involving high-temperature heating, allowing the adhesive layer to be more easily peeled off and reducing adhesive residue. If the content is 15 parts by weight or less, the initial adhesive strength of the adhesive layer is increased and clouding of the adhesive layer can be suppressed. A more preferred lower limit of the content is 3 parts by weight and a more preferred upper limit is 10 parts by weight, and an even more preferred lower limit is 4 parts by weight and an even more preferred upper limit is 6 parts by weight.

The weight ratio of the silicone oil to the silicone graft copolymer (weight of silicone oil/weight of silicone graft copolymer) preferably has a lower limit of 0.1 and an upper limit of 1.0. If the weight ratio is 0.1 or more, adhesion enhancement can be further reduced even when the adhesive is attached to a resin-based adherend and subjected to a process involving high-temperature heating, allowing the pressure-sensitive adhesive layer to be more easily peeled off and reducing adhesive residue. If the weight ratio is 1.0 or less, contamination of the adherend due to bleeding out of the silicone oil can be further reduced. The lower limit of the weight ratio is more preferably 0.2, and the upper limit is more preferably 0.8, with an even more preferred lower limit being 0.3 and an even more preferred upper limit being 0.7.

The pressure-sensitive adhesive composition of the present invention preferably further contains a crosslinking agent. When the pressure-sensitive adhesive composition of the present invention contains the crosslinking agent, the adhesive polymer is crosslinked, making it easier to adjust the cohesive strength of the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition. As a result, the initial adhesive strength is increased, and even when the pressure-sensitive adhesive composition is subjected to a process involving high-temperature heating in a state where it is attached to a resin-based adherend, adhesion enhancement can be further reduced, allowing the pressure-sensitive adhesive layer to be more easily peeled off and reducing adhesive residue.
Furthermore, by containing the crosslinking agent in the pressure-sensitive adhesive composition of the present invention, when the silicone compound and/or the silicone graft copolymer has a functional group capable of crosslinking with the adhesive polymer, the silicone compound and/or the silicone graft copolymer is bonded to the adhesive polymer via the crosslinking agent, thereby further reducing contamination of the adherend due to bleeding out of the silicone compound and/or the silicone graft copolymer.

The crosslinking agent is not particularly limited, and examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents. Of these, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred because they increase the cohesive strength of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition.

The content of the crosslinking agent is not particularly limited, but from the viewpoint of achieving a more appropriate cohesive force and sufficiently bonding the adhesive polymer with the silicone compound and/or the silicone-based graft copolymer, the preferred lower limit is 0.01 parts by weight and the preferred upper limit is 5 parts by weight per 100 parts by weight of the adhesive polymer. The more preferred lower limit of the content of the crosslinking agent is 0.1 parts by weight and the more preferred upper limit is 3 parts by weight.

The pressure-sensitive adhesive composition of the present invention preferably further contains a polymerization initiator. When the pressure-sensitive adhesive composition of the present invention contains the polymerization initiator, if the pressure-sensitive adhesive polymer has the radically polymerizable unsaturated bond, the pressure-sensitive adhesive layer cures in the presence of the polymerization initiator in response to stimuli such as heat or light, increasing the elastic modulus and decreasing the adhesive strength. This reduces adhesion enhancement even when the pressure-sensitive adhesive layer is attached to a resin-based adherend and undergoes a process involving high-temperature heating, making it easier to peel off the pressure-sensitive adhesive layer and reducing adhesive residue. The polymerization initiator is not particularly limited, and examples include photopolymerization initiators and thermal polymerization initiators. Of these, thermal polymerization initiators are preferred because they can cure the pressure-sensitive adhesive layer using the heat generated when the adherend is subjected to a heating process, eliminating the need for a separate process for curing the pressure-sensitive adhesive layer, and also because they can cure even when used on an adherend that is opaque to light.

The photopolymerization initiator is not particularly limited, and examples thereof include those that are activated by irradiation with light having a wavelength of 250 to 800 nm. Examples of such photopolymerization initiators include acetophenone derivative compounds, benzoin ether compounds, ketal derivative compounds, phosphine oxide derivative compounds, bis(η5-cyclopentadienyl)titanocene derivative compounds, benzophenone, Michler's ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexylphenyl ketone, and 2-hydroxymethylphenylpropane.
Examples of the acetophenone derivative compounds include methoxyacetophenone. Examples of the benzoin ether compounds include benzoin propyl ether and benzoin isobutyl ether. Examples of the ketal derivative compounds include benzyl dimethyl ketal and acetophenone diethyl ketal. These photopolymerization initiators may be used alone or in combination of two or more.

The thermal polymerization initiator is not particularly limited, and examples include those that decompose when heated to generate active radicals that start the polymerization reaction. Specific examples include dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoyl, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, and di-t-butyl peroxide.

The content of the polymerization initiator is not particularly limited and is determined appropriately depending on the types of the adhesive polymer and the polymerization initiator. However, a preferred lower limit is 0.5 parts by weight and a preferred upper limit is 10 parts by weight, more preferably 1 part by weight and more preferably 8 parts by weight, per 100 parts by weight of the adhesive polymer.

The pressure-sensitive adhesive composition of the present invention may contain known additives such as inorganic fillers such as fumed silica, plasticizers, resins, surfactants, waxes, particulate fillers, antioxidants, and gas generating agents.

The present invention also provides a pressure-sensitive adhesive tape having a substrate and a pressure-sensitive adhesive layer laminated on at least one surface of the substrate, wherein the pressure-sensitive adhesive layer contains the pressure-sensitive adhesive composition of the present invention.
The pressure-sensitive adhesive tape of the present invention may be a single-sided pressure-sensitive adhesive tape or a double-sided pressure-sensitive adhesive tape, as long as it has a pressure-sensitive adhesive layer on at least one surface of the substrate. In the case of a double-sided pressure-sensitive adhesive tape, only one of the pressure-sensitive adhesive layers may contain the pressure-sensitive adhesive composition of the present invention, or both pressure-sensitive adhesive layers may contain the pressure-sensitive adhesive composition of the present invention.

The thickness of the adhesive layer is not particularly limited, but a preferred lower limit is 5 μm and a preferred upper limit is 100 μm. If the thickness of the adhesive layer is within the above range, the adhesive tape can be attached to the adherend with sufficient adhesive strength, and adhesive residue can be reduced after the process is completed. A more preferred lower limit of the thickness of the adhesive layer is 10 μm and a more preferred upper limit is 60 μm.

The material constituting the substrate is not particularly limited, but is preferably a heat-resistant material. Examples of heat-resistant materials include polyethylene terephthalate, polyethylene naphthalate, polyacetal, polyamide, polycarbonate, polyphenylene ether, polybutylene terephthalate, ultra-high molecular weight polyethylene, syndiotactic polystyrene, polyarylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, and liquid crystal polymer. Of these, polyimide is preferred due to its excellent heat resistance.

The thickness of the substrate is not particularly limited, but a preferred lower limit is 25 μm and a preferred upper limit is 250 μm. If the thickness of the substrate is within the above range, the resulting adhesive tape will be easy to handle. A more preferred lower limit for the thickness of the substrate is 50 μm and a more preferred upper limit is 125 μm.

The method for producing the pressure-sensitive adhesive tape of the present invention is not particularly limited, and examples include the following method. First, a pressure-sensitive adhesive composition solution is obtained by adding silicone oil, a silicone-based graft copolymer, and, if necessary, a crosslinking agent, a polymerization initiator, and other additives to a solution of the pressure-sensitive adhesive polymer and mixing them. Next, the pressure-sensitive adhesive composition solution is applied to a release film and dried to form a pressure-sensitive adhesive layer. The obtained pressure-sensitive adhesive layer is laminated to a substrate to produce a pressure-sensitive adhesive tape.

The applications of the pressure-sensitive adhesive composition and pressure-sensitive adhesive tape of the present invention are not particularly limited, but they are preferably used in the manufacturing process of electronic components such as semiconductor devices and display devices (OLED, liquid crystal display devices, etc.). More specifically, in the manufacture of electronic components, they are preferably used when an adherend is fixed to a support plate via the pressure-sensitive adhesive composition or pressure-sensitive adhesive tape and the adherend fixed to the support plate is then treated. A method for manufacturing a semiconductor device using the pressure-sensitive adhesive tape of the present invention also constitutes one aspect of the present invention.

The pressure-sensitive adhesive composition and pressure-sensitive adhesive tape of the present invention can be easily peeled off while reducing contamination of the adherend, even when subjected to a process involving high-temperature heating while attached to a resin-based adherend. Therefore, the pressure-sensitive adhesive composition and pressure-sensitive adhesive tape of the present invention can be suitably used when attached to a resin-based adherend such as polyimide or epoxy resin and subjected to a process involving heating at higher temperatures than conventionally possible, specifically, at temperatures as high as 200°C or higher. Examples of such processes involving heating at high temperatures include reflow processes, sputtering processes, vapor deposition processes, etching processes, chemical vapor deposition (CVD) processes, physical vapor deposition (PVD) processes, resist coating processes, patterning processes, molding processes, and other heat- or heat-generating processes.

The present invention provides a pressure-sensitive adhesive composition that forms a pressure-sensitive adhesive layer that can be easily peeled off while reducing contamination of the adherend, even when the composition is attached to a resin-based adherend and subjected to a process involving high-temperature heating. The present invention also provides a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition, and a method for manufacturing a semiconductor device using the pressure-sensitive adhesive tape.

The following examples further illustrate aspects of the present invention, but the present invention is not limited to these examples.

(Synthesis of Acrylic Polymer A)
A reactor equipped with a thermometer, a stirrer, and a cooling tube was prepared, and 96.9 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, 0.1 parts by weight of hydroxyethyl acrylate, and 80 parts by weight of ethyl acetate were added to the reactor. The reactor was heated to initiate reflux. Subsequently, 0.01 parts by weight of V-60 (2,2'-azobisisobutyronitrile, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator to the reactor, and a polymerization reaction was carried out at 60°C for 8 hours to obtain an ethyl acetate solution of acrylic polymer A.
The obtained acrylic polymer A-containing solution was diluted 50 times with tetrahydrofuran (THF). The obtained diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The obtained filtrate was supplied to a gel permeation chromatograph (Waters, 2690 Separations Model), and GPC measurement was performed under conditions of a sample flow rate of 1 mL/min and a column temperature of 40 ° C. The polystyrene-equivalent molecular weight of the acrylic polymer A was measured, and the weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) were determined. The weight average molecular weight (Mw) was 1,480,000, and the molecular weight distribution (Mw/Mn) was 4.1. A GPC KF-806L (Showa Denko KK) was used as the column, and a differential refractometer was used as the detector.

(Synthesis of Acrylic Polymer B)
A reactor equipped with a thermometer, a stirrer, and a cooling tube was prepared, and 79 parts by weight of 2-ethylhexyl acrylate, 1 part by weight of acrylic acid, 20 parts by weight of hydroxyethyl acrylate, and 80 parts by weight of ethyl acetate were added to the reactor as monomers. The reactor was heated to initiate reflux. Subsequently, 0.05 parts by weight of V-60 (2,2'-azobisisobutyronitrile, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator to initiate polymerization under reflux. Next, 0.15 parts by weight of V-60 (2,2'-azobisisobutyronitrile, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added again 2 hours after the start of polymerization. The polymerization reaction was carried out under reflux for 8 hours from the start of polymerization, yielding a polymer-containing solution.
A reaction vessel was charged with 10 ppm of hydroquinone relative to 100 parts by weight of the obtained polymer, and the mixture was heated to 60°C. Subsequently, 8 parts by weight of 2-methacryloyloxyethyl isocyanate (MOI) was added dropwise to the reaction vessel over 60 minutes, and the mixture was allowed to react at 60°C for a further 120 minutes, thereby obtaining a solution containing acrylic polymer B. The weight average molecular weight (Mw) of acrylic polymer B was determined in the same manner as for acrylic polymer A, and it was found that the molecular weight distribution (Mw/Mn) was 5.3.

(Synthesis Examples 1 to 6 (Synthesis of Silicone-Based Graft Copolymers))
A reactor equipped with a thermometer, a stirrer, and a condenser was prepared. A total of 100 parts by weight of the monomer mixture shown in Table 1 and 80 parts by weight of ethyl acetate were added to the reactor. The reactor was heated to initiate reflux. Subsequently, 0.1 parts by weight of 2,2'-azobisisobutyronitrile (V-60, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator to the reactor, and polymerization was initiated under reflux. Next, 0.1 parts by weight of 2,2'-azobisisobutyronitrile (V-60, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added 1 hour after the start of polymerization, and 0.2 parts by weight of 2,2'-azobisisobutyronitrile (V-60, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added 6 hours after the start of polymerization to continue the polymerization reaction. Then, 7 hours after the start of polymerization, an ethyl acetate solution of a silicone-based graft copolymer (Synthesis Examples 1 to 5) was obtained. The weight average molecular weights (Mw) were determined in the same manner as for acrylic polymer A, and were 78,000 in Synthesis Example 1, 74,000 in Synthesis Example 2, 66,000 in Synthesis Example 3, 67,000 in Synthesis Example 4, 59,000 in Synthesis Example 5, and 65,000 in Synthesis Example 6.

2EHA: 2-ethylhexyl acrylate silicone macromonomer: one-terminated methacryloyl-modified polydimethylsiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., weight average molecular weight 4600)
AAc: acrylic acid 4HBA: 4-hydroxybutyl acrylate

Example 1
(Manufacturing of adhesive tapes)
Ethyl acetate was added to the acrylic polymer A-containing solution per 100 parts by weight of the nonvolatile content, and the mixture was stirred. Silicone oil, a silicone graft copolymer, and a crosslinking agent, as shown in Table 2, were then added and stirred to obtain a pressure-sensitive adhesive composition solution with a nonvolatile content of 30% by weight. The obtained pressure-sensitive adhesive composition solution was applied with a doctor knife to the corona-treated surface of a 50 μm-thick transparent polyethylene naphthalate film, one side of which had been corona-treated, so that the dried film thickness would be 40 μm. The coating solution was then dried by heating at 110°C for 5 minutes. This was then left to stand and aged at 40°C for 3 days to obtain a pressure-sensitive adhesive tape.

(Examples 2 to 15, Comparative Examples 1 to 8)
Pressure-sensitive adhesive tapes were obtained in the same manner as in Example 1, except that the formulation of the pressure-sensitive adhesive composition was changed as shown in Table 2 or Table 3.

<Evaluation>
The pressure-sensitive adhesive tapes obtained in the Examples and Comparative Examples were evaluated by the following methods. The results are shown in Table 2 or Table 3.

(1) Evaluation of adhesive strength after heating: The adhesive tape was cut into 25 mm widths. Under an environment of room temperature 23°C and relative humidity 50%, the cut adhesive tape was attached to a polyimide film (Upilex, manufactured by Ube Industries, Ltd.) at a speed of 10 mm/sec using a 2 kg pressure rubber roller. Next, a heat treatment at 220°C for 2 hours was performed once. After cooling, the adhesive tape was peeled off at a speed of 300 mm/min according to JIS Z0237, and the 180-degree peel strength was measured. Peel strengths of 0.05 N/25 mm or less were indicated by ⊚, those greater than 0.05 N/25 mm but less than 0.2 N/25 mm by ◯, and those of 0.2 N/25 mm or more by ×.
In Example 15, since the adhesive layer was a photocurable type, before the heat treatment at 220°C for 2 hours, a high-pressure mercury UV irradiator was used to irradiate the adhesive layer with ultraviolet light of 405 nm so that the irradiation dose to the adhesive layer was 3000 mJ/ ^cm2 .

(2) Evaluation of staining properties After evaluation of adhesive strength after heating, the surface of the polyimide film (Upilex, manufactured by Ube Industries, Ltd.) was visually inspected for residues to evaluate staining properties.
The case where no residue was observed was indicated by ◯, and the case where residue was observed was indicated by △.

Silicone oil: KF-96-10cs (Shin-Etsu Chemical Co., Ltd., weight average molecular weight 1000)
Epoxy-modified silicone: X-22-163C (Shin-Etsu Chemical Co., Ltd., weight-average molecular weight 4600)
Epoxy crosslinking agent: Tetrad C (manufactured by Mitsubishi Gas Chemical Company, Inc.)
Isocyanate-based crosslinking agent: Coronate L (manufactured by Nippon Polyurethane Co., Ltd.)
Photopolymerization initiator: Omnirad 369 (manufactured by IGM Resins)

The present invention provides a pressure-sensitive adhesive composition that forms a pressure-sensitive adhesive layer that can be easily peeled off while reducing contamination of the adherend, even when the composition is attached to a resin-based adherend and subjected to a process involving high-temperature heating. The present invention also provides a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition, and a method for manufacturing a semiconductor device using the pressure-sensitive adhesive tape.

Claims (9)

The adhesive composition contains an adhesive polymer, a silicone oil, and a silicone graft copolymer having a structural unit derived from a silicone macromonomer,
The pressure-sensitive adhesive composition is characterized in that the silicone graft copolymer has a functional group capable of crosslinking with the pressure-sensitive adhesive polymer. 2. The pressure-sensitive adhesive composition according to claim 1, wherein the silicone graft copolymer contains 1% by weight or more and 90% by weight or less of a structural unit derived from the silicone macromonomer and 0.1% by weight or more and 30% by weight or less of a structural unit derived from a monomer having a functional group capable of crosslinking with the pressure-sensitive adhesive polymer. 3. The pressure-sensitive adhesive composition according to claim 1 , wherein the silicone oil has a functional group capable of crosslinking with the adhesive polymer. 4. The pressure-sensitive adhesive composition according to claim 1 , wherein the content of the silicone graft copolymer is 1 part by weight or more and 15 parts by weight or less per 100 parts by weight of the pressure-sensitive adhesive polymer. 5. The pressure-sensitive adhesive composition according to claim 1, wherein the weight ratio of said silicone oil to said silicone graft copolymer is 0.1 or more and 1.0 or less. 6. The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive polymer is an acrylic polymer. 7. An adhesive tape comprising a substrate and an adhesive layer laminated on at least one surface of the substrate, wherein the adhesive layer contains the adhesive composition according to claim 1. 8. The adhesive tape according to claim 7, which is used in the manufacturing process of electronic components. A method for manufacturing a semiconductor device, comprising using the adhesive tape according to claim 7 or 8 .