JP2010070610A - Adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive tape that has sufficient adhesive force to an adherend having a gold surface and is readily peeled by irradiation with ultraviolet rays or the like. <P>SOLUTION: The adhesive tape has an adhesive agent layer comprising a photocurable adhesive agent and a compound represented by general formula (1) on at least one surface of a substrate. In the formula (1), R is an alkyl group or the like. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a pressure-sensitive adhesive tape that has sufficient adhesion to a gold surface adherend and can be easily peeled off by irradiation with ultraviolet rays or the like.

The performance required for adhesive tapes varies depending on the application, but depending on the application, it can be firmly adhered and fixed to the adherend as long as necessary, but it must be easily peeled off after use. There is.
For example, in the IC chip manufacturing process, when a thick film wafer cut from a high-purity silicon single crystal or the like is ground to a predetermined thickness to form a thin film wafer, the thick film wafer is bonded to a support plate for reinforcement. By doing so, it has been proposed to work efficiently. At this time, as the double-sided adhesive tape for bonding the thick film wafer and the support plate, while firmly bonding during the grinding process, from the support plate without damaging the thin film wafer obtained after the grinding process is completed It must be peeled off.

As a method for peeling off the adhesive tape, for example, it is conceivable to peel it off by applying a physical force. However, this method may cause serious damage when the adherend is soft. Moreover, the method of peeling off a double-sided adhesive tape using the solvent which can melt | dissolve an adhesive is also considered. However, this method cannot be used when the adherend is attacked by a solvent.
As described above, the pressure-sensitive adhesive tape once used for bonding has a problem that it is more difficult to peel off the adherend without damaging the adherend as the adhesive strength is stronger.

On the other hand, Patent Document 1 discloses a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of a photocurable pressure-sensitive adhesive that is polymerized and cross-linked by irradiating ultraviolet rays or the like. Such an adhesive tape has high adhesive strength and can securely fix the adherend. On the other hand, the adhesive layer is cross-linked and cured by irradiating ultraviolet rays or the like, and the elastic modulus is increased rapidly. Can be easily peeled off. However, the pressure-sensitive adhesive tape described in Patent Document 1 can exhibit high adhesive strength when the adherend is a silicon wafer or the like, but the adherend includes a surface containing gold (hereinafter, “gold surface adherend”). In other words, there is a problem that high adhesive strength cannot be exhibited.

In general, as a method for improving the adhesion to a gold surface adherend, it is known to incorporate a compound containing an S group in an adhesive. When a compound containing an S group is blended, an S-Au bond is formed between the compound containing the S group and the gold surface adherend, thereby improving adhesion to the gold surface adherend and high adhesion. It is thought that it can exhibit the nature. However, when a compound containing an S group is added to an adhesive tape having a pressure-sensitive adhesive layer made of a photocurable adhesive, the adhesion to a gold surface adherend can be improved, but even when irradiated with ultraviolet rays or the like. There was a problem that the adhesive strength was not sufficiently lowered and easy peeling could not be realized.

Japanese Patent Laid-Open No. 06-049415

An object of this invention is to provide the adhesive tape which has sufficient adhesive force with respect to a gold | metal surface to-be-adhered body, and can be peeled easily by irradiating an ultraviolet-ray etc.

The present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer containing a photocurable pressure-sensitive adhesive and a compound represented by the following general formula (1) on at least one surface of a substrate.

In formula (1), R represents an alkyl group.
The present invention is described in detail below.

When the compound represented by General formula (1) is mix | blended in the adhesive layer which consists of a photocurable adhesive among the compounds containing S group, these inventors with respect to a gold | metal surface adherend. The present invention was completed by finding out that both high adhesive strength and easy peelability after irradiation with ultraviolet rays or the like can be achieved.

The pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer on at least one surface of the substrate.
The pressure-sensitive adhesive tape of the present invention may be a single-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer is formed only on one side, or may be a double-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer is formed on both sides.

Although it does not specifically limit as said base material, It is preferable that it is what permeate | transmits or passes light, For example, transparent, such as an acryl, an olefin, a polycarbonate, vinyl chloride, ABS, a polyethylene terephthalate (PET), nylon, urethane, a polyimide And a sheet made of a simple resin, a sheet having a network structure, a sheet having holes, and the like.

The pressure-sensitive adhesive layer contains a photocurable pressure-sensitive adhesive and a compound represented by the general formula (1).
It does not specifically limit as said photocurable adhesive, A conventionally well-known thing can be used. Specifically, for example, a (meth) acrylic acid alkyl ester-based polymerizable polymer having a radical polymerizable unsaturated bond in the molecule and a radical polymerizable polyfunctional oligomer or monomer as main components are necessary. The thing using the photocurable adhesive which contains a photoinitiator according to it, etc. are mentioned.
The pressure-sensitive adhesive layer made of such a photo-curable pressure-sensitive adhesive is uniformly and rapidly polymerized and integrated by light irradiation, so that the elastic modulus increases significantly due to polymerization and curing. Adhesive strength is greatly reduced.

The polymerizable polymer is prepared by, for example, previously synthesizing a (meth) acrylic polymer having a functional group in the molecule (hereinafter referred to as a functional group-containing (meth) acrylic polymer) It can be obtained by reacting with a compound having a reactive functional group and a radical polymerizable unsaturated bond (hereinafter referred to as a functional group-containing unsaturated compound).

The functional group-containing (meth) acrylic polymer is an acrylic having an alkyl group usually in the range of 2 to 18 as a polymer having adhesiveness at room temperature, as in the case of a general (meth) acrylic polymer. By copolymerizing an acid alkyl ester and / or methacrylic acid alkyl ester as a main monomer, a functional group-containing monomer, and, if necessary, another modifying monomer copolymerizable therewith by a conventional method It is obtained. The weight average molecular weight of the functional group-containing (meth) acrylic polymer is usually about 200,000 to 2,000,000.

Examples of the functional group-containing monomer include carboxyl group-containing monomers such as acrylic acid and methacrylic acid, hydroxyl group-containing monomers such as hydroxyethyl acrylate and hydroxyethyl methacrylate, and epoxy such as glycidyl acrylate and glycidyl methacrylate. Examples thereof include group-containing monomers, isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate, and amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate.
Examples of other modifying monomers that can be copolymerized include various monomers used in general (meth) acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.

The functional group-containing unsaturated compound to be reacted with the functional group-containing (meth) acrylic polymer is the same as the functional group-containing monomer described above according to the functional group of the functional group-containing (meth) acrylic polymer. it can. For example, when the functional group of the functional group-containing (meth) acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used, and when the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used, and when the functional group is an amino group, an epoxy group-containing monomer is used.

The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5, so that the three-dimensional network of the pressure-sensitive adhesive layer can be efficiently formed by heating or light irradiation. 000 or less and the number of radically polymerizable unsaturated bonds in the molecule is 2 to 20. Examples of such more preferred polyfunctional oligomers or monomers include trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate. Or the above-mentioned methacrylates etc. are mentioned. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and methacrylates similar to those described above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

Examples of the photopolymerization initiator include those activated by irradiation with light having a wavelength of 250 to 800 nm. Examples of such a photopolymerization initiator include acetophenone derivative compounds such as methoxyacetophenone. Benzoin ether compounds such as benzoin propyl ether and benzoin isobutyl ether, ketal derivative compounds such as benzyldimethyl ketal and acetophenone diethyl ketal, phosphine oxide derivative compounds, and bis (η5-cyclopentadienyl) titanocene derivative compounds , Benzophenone, Michler ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethylphenol Examples include photo radical polymerization initiators such as nylpropane. These photoinitiators may be used independently and 2 or more types may be used together.

The compound represented by the general formula (1) has a role of imparting adhesive force to the gold surface adherend to the pressure-sensitive adhesive tape of the present invention. On the other hand, even if the compound represented by the general formula (1) is blended in the pressure-sensitive adhesive layer composed of the photocurable pressure-sensitive adhesive, it can be easily peeled off by irradiation with ultraviolet rays or the like.

Although the reason for this is not clear, it is considered as follows.
As described above, when a compound containing an S group is added to the pressure-sensitive adhesive, an S—Au bond is formed between the compound containing the S group and the gold surface adherend. It is considered that the adhesiveness to the surface is improved and the adhesiveness is improved. However, among S-containing compounds, in the case of an S group that does not bond to hydrogen (an S group that is not an SH group), the S—Au bond is not a strong covalent bond, and the interaction is caused by a relatively moderate intermolecular force. It is thought that. Therefore, compared with a compound containing an SH group, in the case of a compound containing an S group that is not an SH group, such as the compound represented by the general formula (1), it adheres more than necessary to the gold surface adherend. Therefore, it can be easily peeled off by irradiating with ultraviolet rays or the like.

However, any compound containing an S group that is not an SH group has “adhesive strength to the gold surface adherend and can be easily peeled off by irradiating ultraviolet rays or the like. The effect of “is” cannot be demonstrated. Such an effect can be exhibited only when the compound represented by the general formula (1) is used. This is thought to be because the S atom of the compound having an S group that does not form an S—Au bond has a structure that does not suffer from steric hindrance.

Examples of commercially available compounds represented by the general formula (1) include Irgacure IRC907 (R is CH ₃ manufactured by Ciba Japan).

As a compounding quantity of the compound represented by General formula (1), the preferable minimum with respect to 100 weight part of said photocurable adhesives is 1 weight part, and a preferable upper limit is 10 weight part. If the compounding amount of the compound represented by the general formula (1) is less than 1 part by weight, the effect of improving the adhesion to the gold surface adherent may be insufficient. The adhesion force to the surface may become too large, the compound represented by the general formula (1) may be deposited on the surface of the pressure-sensitive adhesive, or the pressure-sensitive adhesive force may be reduced more than necessary. The more preferable lower limit of the compounding amount of the compound represented by the general formula (1) is 2 parts by weight, and the more preferable upper limit is 5 parts by weight.

The pressure-sensitive adhesive layer may contain a gas generating agent that generates gas when irradiated with light. When the pressure-sensitive adhesive layer containing such a gas generating agent is irradiated with light, the photo-curing pressure-sensitive adhesive is cross-linked and cured, and the elastic modulus of the entire pressure-sensitive adhesive layer increases, and is generated in such a hard pressure-sensitive adhesive layer. Since the released gas is released from the pressure-sensitive adhesive layer to the adhesive interface and peels at least a part of the adhesive surface, the pressure-sensitive adhesive tape can be peeled off more easily.

Although it does not specifically limit as said gas generating agent, For example, an azide compound, an azo compound, etc. are mentioned. Among these, an azide compound having excellent heat resistance is suitable considering that the pressure-sensitive adhesive tape of the present invention is used during processing of a semiconductor having a vacuum heating process.
The azide compound is not particularly limited, and can be obtained, for example, by ring-opening polymerization of 3-azidomethyl-3-methyloxetane, terephthalazide, p-tert-butylbenzazide, or 3-azidomethyl-3-methyloxetane. Examples thereof include a polymer having an azide group such as glycidyl azide polymer (GAP).

The pressure-sensitive adhesive layer may appropriately contain various polyfunctional compounds that are blended in a general pressure-sensitive adhesive such as an isocyanate compound, a melamine compound, and an epoxy compound for the purpose of adjusting the cohesive force as the pressure-sensitive adhesive. In addition, known additives such as an antistatic agent, a plasticizer, a resin, a surfactant, a wax, and a fine particle filler can be added. Furthermore, you may mix | blend a heat stabilizer and antioxidant in order to improve stability of an adhesive.

It does not specifically limit as thickness of the said adhesive layer, A preferable minimum is 5 micrometers. If the thickness of the pressure-sensitive adhesive layer is less than 5 μm, sufficient adhesive strength may not be exhibited. A more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 10 μm.

The method for producing the pressure-sensitive adhesive tape of the present invention is not particularly limited. For example, a photocurable pressure-sensitive adhesive in which a compound represented by the general formula (1) is blended on a substrate is used using a doctor knife or a spin coater. A conventionally known method such as coating may be used.

The pressure-sensitive adhesive tape of the present invention can exhibit a sufficient pressure-sensitive adhesive force even on a gold surface adherend. Further, it can be easily peeled off by irradiating with ultraviolet rays or the like.
Examples of the gold surface adherend include a Si wafer having an Au film formed on the surface by sputtering, plating, or the like.

ADVANTAGE OF THE INVENTION According to this invention, it can provide the adhesive tape which has sufficient adhesive force with respect to a gold | metal surface to-be-adhered body, and can be peeled easily by irradiating an ultraviolet-ray etc.

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

Example 1
(1) Preparation of photocurable pressure-sensitive adhesive The following compounds are dissolved in ethyl acetate, polymerized by irradiation with ultraviolet rays, and an ethyl acetate solution of a photocurable pressure-sensitive adhesive made of an acrylic copolymer having a weight average molecular weight of 700,000. Got.
Butyl acrylate 79 parts by weight Ethyl acrylate 15 parts by weight Acrylic acid 1 part by weight 2-hydroxyethyl acrylate 5 parts by weight Photopolymerization initiator 1 part by weight (Irgacure 651, 50% ethyl acetate solution)

(2) Preparation of composition solution for pressure-sensitive adhesive layer The reaction was conducted by adding 3.5 parts by weight of 2-isocyanatoethyl methacrylate to 100 parts by weight of the resin solid content of the obtained ethyl acetate solution of the photocurable pressure-sensitive adhesive. Furthermore, 2 parts by weight of Irgacure IRC907 (a compound in which R is CH ₃ in the general formula (1), manufactured by Ciba Japan) based on 100 parts by weight of the resin solid content of the ethyl acetate solution after the reaction, start of photopolymerization A composition solution for an adhesive layer was prepared by mixing 0.2 parts by weight of an agent (Irgacure 651) and 0.5 parts by weight of polyisocyanate.

(3) Manufacture of pressure-sensitive adhesive tape The obtained composition solution for pressure-sensitive adhesive layer was subjected to a corona treatment on a transparent polyethylene terephthalate (PET) film having a thickness of 75 μm with one side subjected to a corona treatment. Coating was performed with a doctor knife so as to be 15 μm, and the coating solution was dried by heating at 110 ° C. for 5 minutes. The pressure-sensitive adhesive layer after drying showed adhesiveness in a dry state. Next, a PET film that was subjected to a release treatment was attached to the surface of the pressure-sensitive adhesive layer. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain an adhesive tape.

(Comparative Example 1)
An adhesive tape was produced in the same manner as in Example 1 except that Irgacure IRC907 was not added.

(Comparative Example 2)
An adhesive tape was produced in the same manner as in Example 1 except that 3-mercaptopropyltrimethoxysilane (the following formula (2)) was used instead of Irgacure IRC907.

(Comparative Example 3)
An adhesive tape was produced in the same manner as in Example 1 except that KAYACURE DETX-S (manufactured by Nippon Kayaku Co., Ltd., the following formula (3)) was used instead of Irgacure IRC907.

(Comparative Example 4)
An adhesive tape was produced in the same manner as in Example 1 except that KAYACURE CTX (manufactured by Nippon Kayaku Co., Ltd., the following formula (4)) was used instead of Irgacure IRC907.

(Comparative Example 5)
An adhesive tape was produced in the same manner as in Example 1 except that KAYACURE BMS (manufactured by Nippon Kayaku Co., Ltd., the following formula (5)) was used instead of Irgacure IRC907.

(Evaluation)
About the adhesive tape manufactured in Example 1 and Comparative Examples 1-5, the following method evaluated.
The results are shown in Table 1.

(1) Evaluation of adhesive strength at 23 ° C. Adhesive tape cut to a width of 25 mm × length of 100 mm on a Si wafer having an Au film formed on the entire surface by sputtering, using a 2 kg roller, temperature 23 ° C., humidity 50% Affixed in an atmosphere. Then, it was left to stand for 20 minutes, and a 180 ° tensile test was performed with an autograph (AG-ISMS, manufactured by Shimadzu Corporation) under the same temperature and humidity conditions at a tensile speed of 300 mm / min.
A similar evaluation was performed on a Si wafer on which no Au film was formed.

(2) Evaluation of adhesive strength at 90 ° C. Adhesive tape cut to a width of 25 mm × length of 100 mm on a Si wafer having an Au film formed on the entire surface by sputtering, using a 2 kg roller, temperature 23 ° C., humidity 50% Affixed in an atmosphere. Then, after leaving it for 20 minutes and leaving it at 90 ° C. in a 50% humidity atmosphere for 5 minutes, a 180 ° tensile test was performed with an autograph (AG-ISMS, manufactured by Shimadzu Corporation) at a pulling speed of 300 mm / min. went.
A similar evaluation was performed on a Si wafer on which no Au film was formed.

(3) Evaluation of adhesive strength after UV irradiation Adhesive tape cut to a width of 25 mm and a length of 100 mm is applied to a Si wafer having an Au film formed on the entire surface by sputtering, using a 2 kg roller, temperature 23 ° C., humidity 50 Affixed in% atmosphere. Thereafter, the sample was left for 20 minutes, irradiated with 2000 mJ of ultraviolet rays, and then subjected to a 180 ° tensile test with an autograph (AG-ISMS, manufactured by Shimadzu Corporation) at a tensile speed of 300 mm / min.
A similar evaluation was performed on a Si wafer on which no Au film was formed.

ADVANTAGE OF THE INVENTION According to this invention, it can provide the adhesive tape which has sufficient adhesive force with respect to a gold | metal surface to-be-adhered body, and can be peeled easily by irradiating an ultraviolet-ray etc.

Claims (1)

A pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer containing a photocurable pressure-sensitive adhesive and a compound represented by the following general formula (1) on at least one surface of a substrate.

In formula (1), R represents an alkyl group.