KR101174854B1 - Radiation cured peeling type adhesive composition and adhesive sheet for semiconductor wafer back-grinding - Google Patents

Abstract

상기 화학식에서, R₁은 수소 또는 메틸이며, R₂는 탄소수 4 ~ 12의 알킬이다.The present invention relates to a radiation-peelable pressure-sensitive adhesive composition and a pressure sensitive adhesive sheet for processing a semiconductor wafer comprising the composition, specifically, (a) one or more acrylic monomers represented by the following general formula (1) and acrylic monomers containing a hydroxy group The present invention relates to a pressure-sensitive adhesive composition comprising a polymerized adhesive resin, (b) a diisocyanate compound and an acrylic monomer containing a (c) hydroxy group, and an adhesive sheet using the composition. In the case of using the pressure-sensitive adhesive composition of the present invention, the adhesive force is reduced by the curing reaction by irradiation with radiation, so that peeling from the semiconductor wafer is easy, no contamination remains on the semiconductor wafer after peeling, and the adhesive sheet for the ultra-thin wafer manufacturing process is economically used. There is an advantage that it can be manufactured.
[Formula 1]

In the above formula, R ₁ is hydrogen or methyl, R ₂ is alkyl having 4 to 12 carbon atoms.

Description

Radiation release adhesive composition and adhesive sheet for semiconductor wafer processing {RADIATION CURED PEELING TYPE ADHESIVE COMPOSITION AND ADHESIVE SHEET FOR SEMICONDUCTOR WAFER BACK-GRINDING}

The present invention relates to a radiation-peelable pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet including the same, wherein the adhesive force is reduced by the curing reaction by radiation irradiation, so that peeling is easy and no residual contaminants remain on the semiconductor wafer after peeling.

In recent years, as the demand for miniaturization and high capacity of IC cards and the like increases, high-density mounting is required and it is required to reduce the thickness of the wafer chip from several hundreds of micrometers to several tens of micrometers or less. In addition, in order to improve productivity, a method of grinding by increasing the diameter of the wafer has been studied. However, as the wafer is developed to be ultra thin, the conventional bonding material causes problems such as breakage caused by impact and bending caused by internal stress, and thus yield is greatly reduced, and various problems are caused by heat generation due to the integration of circuits. handling is difficult.

Therefore, in the semiconductor device manufacturing process, a radiation-curable pressure-sensitive adhesive is used for the process of increasing the size and thickness of the wafer, and a protective sheet (or tape) to prevent damage to the wafer, or a dividing process into element pieces. As the fixing sheet used, a re-peelable pressure-sensitive adhesive sheet which is peeled once again after the process is completed is used.

Adhesive sheet for back grinding (back grinding) damages the circuit surface on which the IC circuit is formed by attaching to the circuit surface in semiconductor processing processes such as back grinding (back grinding) processing and back processing (chemical etching, polishing) of semiconductor wafers. It acts as a wafer protection sheet to prevent over contamination.

Therefore, when peeling the adhesive sheet after the thin wafer manufacturing process is completed by the backside grinding process, the adhesive force of the adhesive layer is reduced by reducing the adhesive force of the pressure-sensitive adhesive layer so that the force applied at the time of peeling due to the strength of the substrate is transferred to the wafer so as not to be broken. It should be able to be easily peeled off from, and there should be no residual contaminants transferred from the adhesive on the circuit surface of the wafer upon peeling. Transfer contaminants can cause defects or package cracks. Since the transfer contaminants are surface precipitated such as low molecular weight components and unreacted crosslinking agents of the resin, it is important to completely react these components. That is, it is desirable that the low molecular weight crosslinker be good in reactivity and that they do not fully react and remain in the reactants.

The pressure-sensitive adhesive used in the back grinding process has a reactor that can be cured, so that the cross-linking curing occurs on the pressure-sensitive adhesive layer by irradiation of radiation (X-ray, ultraviolet ray, electron beam, etc.) after the semiconductor manufacturing process, and accordingly the coating film cohesion increases and shrinks. The adhesion at the interface is significantly reduced, resulting in peeling.

In general, a radiation-curable polymer is a polyfunctional oligomer and a photopolymerization initiator using a styrene-isoprene-styrene copolymer resin-based elastomer or an acrylic resin disclosed in JP-A-2008-111008 as a basic resin and having a photocurable double bond. The composition which consists of essential ingredients is used. In the case of these compositions, crosslinking reaction occurs due to radiation (X-ray, ultraviolet ray, electron beam, etc.) irradiation, which hardens into a three-dimensional network structure, resulting in a sharp decrease in adhesive force. However, residues such as incompletely reacted oligomers are generated as impurities after peeling. There is this.

In Japanese Patent Laid-Open No. 2009-239298, Japanese Patent Laid-Open No. 2010-053346 and Korean Patent No. 323,949, an acrylic polymer having a hydroxyl group and 2-methacryloyl oxyethyl isocyanate are added and reacted in the presence of a catalyst. Disclosed is a radiation curable pressure sensitive adhesive sheet for wafer processing comprising a composition obtained by mixing a base polymer having a photoreactive carbon-carbon double bond obtained with a photopolymerization initiator. However, urethane acrylates such as 2-methacryloyl oxyethyl isocyanate have many restrictions in use, such as difficulty in obtaining them as expensive raw materials.

Accordingly, the present inventors have studied to overcome the problems of the prior art, and as a result, they have sufficient pressure-sensitive adhesiveness and initial adhesive strength before irradiation of the radiation, and the adhesive force is reduced when the irradiation after the wafer thinning process is easy to peel off, and the adhesive remains contaminated. It is an object of the present invention to provide a radiation-peelable pressure-sensitive adhesive composition and a wafer-processing pressure-sensitive adhesive sheet using the pressure-sensitive adhesive composition which does not generate the substance.

The present invention (a) an adhesive resin formed by polymerizing one or more acrylic monomers represented by the following Chemical Formula 1 and an acrylic monomer containing a hydroxyl group; (b) diisocyanate compounds; And (c) provides a pressure-sensitive adhesive composition comprising an acrylic monomer containing a hydroxy group.

[Formula 1]

In Formula 1, R ₁ is hydrogen or methyl, R ₂ is alkyl having 4 to 12 carbon atoms.

In another aspect, the present invention provides a radiation release pressure-sensitive adhesive sheet prepared using the radiation release pressure-sensitive adhesive composition.

In the case of using the radiation-peelable pressure-sensitive adhesive composition of the present invention, the adhesive force is reduced by the curing reaction by radiation irradiation, so that peeling is easy, and there is an advantage that no contaminants remain on the semiconductor wafer after peeling. In addition, when the pressure-sensitive adhesive sheet is manufactured using the pressure-sensitive adhesive composition of the present invention, there is an advantage in that the pressure-sensitive adhesive sheet can be economically provided.

1 is a graph showing a change in the adhesive force before and after ultraviolet irradiation of the adhesive sheet prepared according to Example 1.
2 is a graph showing a change in the adhesive force before and after ultraviolet irradiation of the adhesive sheet prepared according to Example 2.
3 is a graph showing a change in the adhesive force before and after ultraviolet irradiation of the pressure-sensitive adhesive sheet prepared according to Example 3.
4 is a graph showing a change in the adhesive force before and after ultraviolet irradiation of the pressure-sensitive adhesive sheet prepared according to Example 4.
5 is a cross-sectional schematic diagram of a backgrinding tape including a radiation curable pressure sensitive adhesive layer prepared by the present invention (1: base film layer, 2: pressure sensitive adhesive layer, 3: protective film layer).

The present invention relates to a radiation peelable pressure-sensitive adhesive composition and a radiation peelable pressure-sensitive adhesive sheet including the same, wherein the adhesive force is reduced by a curing reaction by radiation irradiation, so that peeling is easy and no contamination remains on the semiconductor wafer after peeling.

The radiation-peelable pressure-sensitive adhesive composition of the present invention comprises: (a) an adhesive resin obtained by polymerizing one or more acrylic monomers represented by the following Chemical Formula 1 and an acrylic monomer containing a hydroxyl group; (b) diisocyanate compounds; And (c) provides a pressure-sensitive adhesive composition comprising an acrylic monomer containing a hydroxy group.

[Formula 1]

In Formula 1, R ₁ is hydrogen or methyl, R ₂ is alkyl having 4 to 12 carbon atoms.

Hereinafter, the present invention will be described in more detail.

(A) the adhesive resin in the radiation-peelable pressure-sensitive adhesive composition of the present invention is characterized in that the acrylic monomer containing one or more acrylic monomers and hydroxyl groups represented by the general formula (1) is polymerized, and the reaction formula is as follows. .

[Reaction Scheme 1]

In Scheme 1, R ₃ and R ₄ are alkyl having 4 to 12 carbon atoms.

In the reaction scheme 1 of the present invention, (a) the acrylic monomer represented by Chemical Formula 1 used for preparing the adhesive resin is characterized in that the side chain R ₂ is an alkyl group having 4 to 12 carbon atoms. In the case of using an alkyl group having 4 to 12 carbon atoms in the side chain R ₂ , it is possible to suppress immersion by acidic and alkaline chemicals used during processing such as wafer etching, and to reduce adhesion to these liquids and to minimize contamination therefrom. Can be effective. When the number of carbon atoms of the side chain R ₂ is less than 4, the Tg of the resin is high, the wettability is low, and there is a disadvantage in that the gelation occurs easily during the crosslinking reaction, and in the case of more than 12, the supply and demand of raw materials becomes difficult. Specific examples of the acrylic monomer represented by Formula 1 include butyl acrylate, isobutyl acrylate, t-butyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, isodecyl acrylate and dodecyl Acrylates such as acrylate, ethylhexyl acrylate and propyl hexyl acrylate and butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, hexyl methacrylate, octyl methacrylate and nonyl methacrylate And methacrylates such as decyl methacrylate, isodecyl methacrylate, dodecyl methacrylate, ethylhexyl methacrylate and propyl hexyl methacrylate, and these may be used alone or in combination of two or more thereof. have. The content of one or more acrylic monomers represented by Formula 1 in the adhesive resin (a) is preferably 70 to 95% by weight, more preferably 80 to 93% by weight. . When the monomer is used at 70 wt% or less, the film coating film is not flexible, and when 95 wt% or more is used, there is a problem in that the adhesive force is strong and the peeling force after irradiation is increased.

In the reaction scheme 1 of the present invention (a) the acrylic monomer containing the hydroxy group used in the manufacture of the adhesive resin serves as a crosslinking agent to combine with the diisocyanate compound in the manufacture of the radiation-peelable pressure-sensitive adhesive composition, and also in the manufacture of the adhesive sheet wafer Combines with the adhesive sheet serves to have a sufficient adhesive force. Specific examples of the acrylic monomer containing a hydroxy group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, polyethylene glycol acrylate, and Although polyethyleneglycol methacrylate etc. are mentioned, It is preferable to use 2-hydroxyethyl methacrylate from the viewpoint of the supply / demand of a raw material, and the ease of manufacture. The monomers may be used alone or in combination of two or more thereof. In the adhesive resin (a), the acrylic monomer containing a hydroxy group is preferably used in an amount of 5 to 30 wt%, more preferably in an amount of 7 to 20 wt%. When the monomer is used in less than 5% by weight, the adhesive force is strong to increase the peeling force after irradiation, and when used in excess of 30% by weight, there is a problem that the film coating film is reduced in flexibility.

In the scheme 1 of the present invention (a) the adhesive resin is prepared by copolymerizing one or two or more acrylic monomers represented by the general formula (1) with an acrylic monomer containing a hydroxyl group. The copolymerization reaction can be carried out by using toluene, ethyl acetate or a mixture thereof as a solvent to cause a polymerization reaction in the presence of benzoyl peroxide or AIBN, which is a radical catalyst. (A) the adhesive resin obtained through the reaction is characterized in that the glass transition temperature (Tg) is -45 ℃ to -35 ℃. As an example of the adhesive resin (a) prepared by the above production method, an acrylic system containing a hydroxy group in a side chain represented by the following Formula 2, which is a copolymer of butyl acrylate, ethylhexyl acrylate, and 2-hydroxyethyl methacrylate Resin may be obtained, but is not limited thereto.

[Formula 2]

In the radiation-peelable pressure-sensitive adhesive composition of the present invention, as shown in Scheme 2, a mixture of (a) the adhesive resin prepared in Scheme 1, (b) a diisocyanate compound and (c) a hydroxy group-containing acrylic monomer is a urethane polymerization catalyst. It is obtained by making it react, and this composition is characterized by including the reactive oligomer obtained by urethane polymerization.

Scheme 2

In Scheme 2, R is 2,4-tolylene, 2,6-tolylene, 1,3-xylene, 1,4-xylene, 4,4'-diphenylmethane, hexamethylene derived from diisocyanate Or isophorone.

A tin compound or a tertiary amine catalyst may be used as a general urethane polymerization catalyst used in the urethane polymerization according to Scheme 2.

By the urethane polymerization catalyst reaction of Scheme 2, not only monofunctional reactive oligomers represented by the following Chemical Formula 3, bifunctional reactive oligomers represented by the following Chemical Formulas 4, 5, and 6 are generated together and present in the pressure-sensitive adhesive composition It will be apparent that this is another feature of the present invention.

(3)

[Formula 4]

[Chemical Formula 5]

[Formula 6]

In Chemical Formulas 3 to 6, R is 2,4-tolylene, 2,6-tolylene, 1,3-xylene, 1,4-xylene, 4,4'-diphenylmethane, Hexamethylene or isophorone.
The bifunctional reactive oligomers represented by Formula 4, Formula 5 or Formula 6 in the pressure-sensitive adhesive composition prepared by Scheme 2 crosslinks upon irradiation with radiation to increase the glass transition temperature of the pressure-sensitive adhesive layer, thereby making the pressure-sensitive adhesive layer harder. It is characterized in that it serves to help the peeling off by easily losing the tack (tack).

In the pressure-sensitive adhesive composition of the present invention, the (b) diisocyanate compound serves as a crosslinking of the monomer (c) having a carbon-carbon double bond with the adhesive resin (a), the formula (3), (4), (5) It serves to manufacture a radiation curable resin and a polyfunctional reactive acrylic monomer represented by 6. Examples of the diisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4, One kind or two or more kinds selected from the group consisting of 4'- diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate can be used. The amount of the diisocyanate compound (b) is preferably used in an amount of 70 to 120 mol%, more preferably 80 to 110 mol%, based on the content of the hydroxy group contained in the adhesive resin (a), Most preferably, 90 to 105 mol% is used. If the (b) diisocyanate compound is used at 70 mol% or less, there is a problem that the crosslinking strength is low and the peel strength is increased after radiation curing. If the diisocyanate compound is used at 120 mol% or more, the resin is easily gelled due to excessive crosslinking. This occurs.

In the pressure-sensitive adhesive composition of the present invention, the (c) hydroxy group-containing acrylic monomer is used to prepare a radiation-curable resin and a polyfunctional acrylic monomer having a carbon-carbon double bond together with (a) an adhesive resin and (b) a diisocyanate compound. Play a role. The acrylic monomer containing the hydroxy group For example, it consists of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, polyethylene glycol acrylate and polyethylene glycol methacrylate. Although one or two or more selected from the group may be used, it is preferable to use 2-hydroxyethyl methacrylate due to the supply and demand of raw materials and ease of manufacture. The acrylic monomer containing the (c) hydroxy group is preferably used 70 to 120 mol%, more preferably 80 to 110 mol% based on the content of the hydroxy group contained in the (a) adhesive resin. Most preferably, 90 to 105 mol% is used. When the acrylic monomer containing the (c) hydroxy group is used in less than 70 mol%, crosslinking is less and the peel strength is increased after radiation curing, and when used in excess of 120 mol%, the resin is likely to gel due to excessive crosslinking.

The pressure-sensitive adhesive composition of the present invention may preferably further include a radiation photopolymerization initiator. Herein, the radiation is not particularly limited as long as it can harden the polymer, and examples thereof include X-rays, ultraviolet rays, and electron beams. The photopolymerization initiator is not particularly limited, and any photopolymerization initiator may be used as long as the molecular chain is broken by ultraviolet rays such as ketone or acetonephenone. When the photopolymerization initiator is added, the carbon-carbon double bond of the pressure-sensitive adhesive layer crosslinks with the radicals, and the glass transition temperature of the pressure-sensitive adhesive layer rises due to the crosslinking reaction, and the pressure-sensitive adhesive layer loses tack, so that the strength is low when peeling. Will be taken. In order to use the ultraviolet wavelength range as a photoinitiator, normally, 2 or more types of compounds are mixed and used. As the initiator in the ultraviolet region, a photosensitizer such as a benzoin compound, an acetophenone compound, or an amine or quinone can be used. As a specific example, 1 type, or 2 or more types chosen from the group which consists of 1-hydroxy cyclo phenyl ketone, dimethoxy hydroxyacetophenone, and beta-chloro anthraquinone can be used. The radiation photopolymerization initiator is preferably used 1 to 10 parts by weight, more preferably 1 to 5 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive composition. If the amount of use is less than 1 part by weight, there is a disadvantage in that the reactivity is slow, and if it exceeds 10 parts by weight, the surface hardness decreases due to an increase in reactivity, thereby reducing the flexibility of the base film.

Hereinafter, the manufacturing method of the adhesive sheet using the radiation peeling adhesive composition by this invention is demonstrated.

The radiation peelable pressure sensitive adhesive sheet (Sheet) of the present invention includes a pressure sensitive adhesive layer composed of the peelable pressure sensitive adhesive composition on a base film. The pressure-sensitive adhesive sheet may be prepared by coating and drying the pressure-sensitive adhesive composition on the base film, or may also be produced by coating and drying the pressure-sensitive adhesive composition on a release type protective sheet to form an pressure-sensitive adhesive layer and transferring it onto the base film. It may be. That is, the pressure-sensitive adhesive layer may be formed by a direct coating method or a method of coating the release film and then drying and transferring the same. In general, when the adhesive coating is directly applied to the polyolefin-based film, shrinkage of the polyolefin-based film occurs during drying of the pressure-sensitive adhesive composition, and thus it is preferable to use a transfer coating method.

A commonly known method may be applied to the method of applying the pressure-sensitive adhesive layer to the base film layer. For example, there is no limitation as long as it can form a coating film such as bar coating, gravure coating, comma coating, reverse roll coating, applicator coating, and spray coating.

Type of the base film is It does not specifically limit, A well-known thing can be used. For example, in the case of the base film used as a protective sheet for wafer grinding, polyester films, such as a polyethylene terephthalate (PET) film and a polybutylene terephthalate (PBT) film, biaxially stretched polypropylene (OPP) ), Polyolefin-based (PO) films such as low density polypropylene (PE) films, various soft polyolefin films, ethylene-vinyl acetate copolymer (EVA) films, and multilayer films including these films. Preferably, a polyolefin-based (PO) film or an ethylene-vinyl acetate copolymer (EVA) film is used.

It is preferable to use the thickness of these base films about 20-300 micrometers. As a base film in the case of using as an adhesive sheet for wafer cutting / separation, it is preferable to add a soft polyvinyl chloride film to the said various films, and to use.

Although the thickness of an adhesive layer can adjust suitably generally in the range of 1-300 micrometers, it is good to use so that it may become 5-100 micrometers more preferably.

The content of the radiation-peelable pressure-sensitive adhesive composition of the present invention can be appropriately adjusted according to the purpose of use, and by adjusting the content of the composition can be adjusted the initial adhesive force and the peeling force. For example, in the case of using the Backgrounder fluoride of the semiconductor wafer, the 2 ~ 40 gf / 25mm (room temperature adhesive strength adhesive holding performance in consideration of the removability after the initial adhesive strength 90 ~ 350 gf / 25mm, irradiation of the semiconductor wafer 180 ^o Peel strength, peeling rate 300 mm / min) may be used, but more preferably, the initial adhesive strength is 100 ~ 150 gf / 25mm, the adhesive strength after irradiation is preferably 15 gf / 25mm or less. The peel force after the ultraviolet irradiation of the present invention is 2 to 40 gf / 25mm, without damaging the ultra-thin wafer, and is characterized in that no residual contaminants remain upon irradiation with radiation. In addition, the pressure-sensitive adhesive sheet using the radiation-peelable pressure-sensitive adhesive composition of the present invention is adhered to and fixed to the surface of the wafer on which the microcircuit pattern is formed on the semiconductor wafer, so that even when exposed to an acid or an alkaline liquid during etching or cleaning of the liquid, immersion by liquid And protect its surface. Therefore, it is possible to prevent the damage and contamination of the circuit surface, and to perform the process of polishing the back of the wafer, there is an advantage that does not leave the adhesive on the wafer surface when peeling the adhesive film from the wafer surface after the process is completed. As a result, it can be used as an excellent adhesive sheet for protecting the surface of the semiconductor wafer in the backgrinding process.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples.

< Example  1>

2-ethylhexyl acrylate (2-EHA, 50g), butyl acrylate (BMA, 40g) and 2-hydroxyethyl methacrylate (2-HEMA, 10g) were added to ethyl acetate solution and then 2,2-azo Copolymerization was carried out at 70 ° C. in the presence of bisisobutyronitrile (AIBN, 0.4 g) to obtain an acrylate-based copolymerized adhesive resin (A-1) having a solid content of 50% by weight.

Toluene diisocyanate (TDI, 13,4g), 2-hydroxyethyl methacrylate (2-HEMA, 10g), and a tin-based urethane polymerization catalyst were added to 100 g of the copolymerized adhesive resin to react with each other to prepare a radiation peelable pressure-sensitive adhesive. . Thereafter, 4 g of 2,2-dimethoxy-2-phenylacetophenone was added to the radiation peelable pressure sensitive adhesive as a photopolymerization initiator, and blocked by contact with light, and stirred for one hour to obtain an ultraviolet curable pressure sensitive adhesive.

The prepared UV-curable pressure-sensitive adhesive was coated on one side of a 100-micron-thick PET film so that the thickness of the dry coating film was 20 microns and dried to obtain an adhesive sheet. The adhesive force of the adhesive before and after irradiation of this pressure sensitive adhesive sheet was measured, and the results are shown in Table 1 and FIG. 1.

< Example  2>

2-ethylhexyl acrylate (2-EHA, 50g), butyl acrylate (BMA, 35g) and 2-hydroxyethyl methacrylate (2-HEMA, 15g) were added to ethyl acetate solution and then 2,2-azo Copolymerization was carried out at 70 ° C. in the presence of bisisobutyronitrile (AIBN, 0.4 g) to obtain an acrylate-based copolymerized adhesive resin (A-2) having a solid content of 50% by weight.

Toluene diisocyanate (TDI, 20 g), 2-hydroxyethyl methacrylate (2-HEMA, 15 g), and a tin-based urethane polymerization catalyst were added and reacted to 100 g of the copolymer adhesive resin to prepare a radiation peelable pressure-sensitive adhesive. Thereafter, 4 g of 2,2-dimethoxy-2-phenylacetophenone was added to the radiation peelable pressure sensitive adhesive as a photopolymerization initiator, and blocked by contact with light, and stirred for one hour to obtain an ultraviolet curable pressure sensitive adhesive.

The prepared UV-curable pressure-sensitive adhesive was coated on one side of a 100-micron-thick PET film so that the thickness of the dry coating film was 20 microns and dried to obtain an adhesive sheet. The adhesive force of the adhesive before and after the irradiation of this adhesive sheet was measured, and the result is shown in Table 1 and FIG.

< Example  3>

2-ethylhexyl acrylate (2-EHA, 50g), hexyl methacrylate (HMA, 30g) and 2-hydroxyethyl methacrylate (2-HEMA, 20g) were added to ethyl acetate solution and then 2,2- Copolymerization was carried out at 70 ° C. in the presence of azobisisobutyronitrile (AIBN, 0.4 g) to obtain an acrylate-based copolymer adhesive resin having a solid content of 50% by weight.

Toluene diisocyanate (TDI, 26.8 g), 2-hydroxyethyl methacrylate (2-HEMA, 20 g), and a tin-based urethane polymerization catalyst were added to 100 g of the copolymer adhesive resin to react with each other to prepare a radiation peelable pressure-sensitive adhesive. Thereafter, 4 g of 2,2-dimethoxy-2-phenylacetophenone was added to the radiation peelable pressure sensitive adhesive as a photopolymerization initiator, and blocked by contact with light, and stirred for one hour to obtain an ultraviolet curable pressure sensitive adhesive.

The prepared UV-curable pressure-sensitive adhesive was coated on one side of a 100-micron-thick PO film so as to have a thickness of 20 microns of a dry coating film and dried to obtain an adhesive sheet. The adhesive force of the adhesive before and after irradiation of this pressure sensitive adhesive sheet was measured, and the results are shown in Table 1 and FIG. 3.

< Example  4>

2-ethylhexyl acrylate (2-EHA, 50g), butyl methacrylate (BMA, 20g) and 2-hydroxyethyl methacrylate (2-HEMA, 30g) were added to ethyl acetate solution and then 2,2- Copolymerization was carried out at 70 ° C. in the presence of azobisisobutyronitrile (AIBN, 0.4 g) to obtain an acrylate-based copolymer adhesive resin having a solid content of 50% by weight.

Toluene diisocyanate (TDI, 26.8 g), 2-hydroxyethyl methacrylate (2-HEMA, 20 g), and a tin-based urethane polymerization catalyst were added to 100 g of the copolymer adhesive resin to react with each other to prepare a radiation peelable pressure-sensitive adhesive. Thereafter, 4 g of 2,2-dimethoxy-2-phenylacetophenone was added to the radiation peelable pressure sensitive adhesive as a photopolymerization initiator, and blocked by contact with light, and stirred for one hour to obtain an ultraviolet curable pressure sensitive adhesive.

The prepared UV-curable pressure-sensitive adhesive was coated on one side of a 100-micron-thick PO film so as to have a thickness of 20 microns of a dry coating film and dried to obtain an adhesive sheet. The adhesive force of the adhesive before and after irradiation of this pressure sensitive adhesive sheet was measured, and the results are shown in Table 1 and FIG. 4.

< Comparative example  1>

Toluene diisocyanate (TDI, 13.4 g), pentaerythritol triacrylate (PETA, 22.9 g) and tin-based urethane polymerization catalyst were added to 100 g of the acrylate-based copolymer adhesive resin (A-1) obtained in Example 1, followed by radiation. A peelable pressure sensitive adhesive was prepared. Thereafter, 4 g of 2,2-dimethoxy-2-phenylacetophenone was added to the radiation peelable pressure sensitive adhesive as a photopolymerization initiator, and blocked by contact with light, and stirred for one hour to obtain an ultraviolet curable pressure sensitive adhesive.

The prepared UV-curable pressure-sensitive adhesive was coated on one side of a 100-micron-thick PO film so as to have a thickness of 20 microns of a dry coating film and dried to obtain an adhesive sheet. The adhesive force of the adhesive before and after irradiation of this adhesive sheet was measured, and the result is shown in Table 1.

< Comparative example  2>

Toluene diisocyanate (TDI, 13.4 g), pentaerythritol triacrylate (PETA, 34.4 g) and tin-based urethane polymerization catalyst were added to 100 g of the acrylate-based copolymer adhesive resin (A-2) obtained in Example 2, followed by radiation. A peelable pressure sensitive adhesive was prepared. Thereafter, 4 g of 2,2-dimethoxy-2-phenylacetophenone was added to the radiation peelable pressure sensitive adhesive as a photopolymerization initiator, and blocked by contact with light, and stirred for one hour to obtain an ultraviolet curable pressure sensitive adhesive.

The prepared UV-curable pressure-sensitive adhesive was coated on one side of a 100-micron-thick PO film so as to have a thickness of 20 microns of a dry coating film and dried to obtain an adhesive sheet. The adhesive force of the adhesive before and after irradiation of this adhesive sheet was measured, and the result is shown in Table 1.

Item Adhesion before UV irradiation (g / 25mm) Adhesion after UV irradiation (g / 25mm) Gel contents
(%) Pollutant Example 1 334 32 81 X Example 2 276 38 89 X Example 3 135 4 93 X Example 4 121 5 97 X Comparative Example 1 334 82 23 ○ Comparative Example 2 276 92 21 ○

[How to measure]

* Radiation: UMC-HM1500-CVK1 (frequency band: 365 nm UV) was irradiated with an exposure dose of 372 mJ / cm ² in a high pressure mercury lamp with a roughness of 1.5 kw / cm.

* 180 degree peeling force measurement: After attaching the adhesive PO tape to SUS 304 cut to 15 mm x 100 mm size, compress it by reciprocating twice with 2 kg rubber roller and store it at room temperature After adhesion and aging at 50 ° C. for 2 hours, the adhesion was measured after 1 hour storage. Each was peeled at 50 N Load Cell using a peel tester (Mecmesin's Multitest 1-d), the dicing tape and the wafer in the upper and lower jig and peeled at a tensile speed of 300 mm / min to measure the load applied during peeling.

* Tackiness measurement: The prepared radiation-peelable pressure-sensitive adhesive sheet was measured by a probe tack tester before and after UV curing according to ASTM D2979-71.

* Gel contents: The pressure-sensitive adhesive sample prepared while changing the amount of UV irradiation was stored in EAc for 24 hours at room temperature, and the polymer remaining without dissolving was separated using a filter. The separated polymer was dried at 80 ° C. until it reached a constant weight and calculated by the following equation.

Gel contents (%) = (W _t / W ₀ ) × 100

W ₀ : weight of polymer after EAc dissolution, W _t : weight of polymer after EAc dissolution

* Contaminant: After attaching the adhesive tape to the surface of the wafer, irradiate within 5 seconds with an exposure dose of 372 mJ / cm ² using a high-pressure mercury lamp with a roughness of 1.5 kw / cm, and then peel the tape from the wafer. The surface of the wafer is observed using an optical microscope.

No contamination was identified. ×

-Some contamination was found. △

-Obvious contamination was identified; ○

Claims (12)

delete delete delete delete delete delete delete Pressure-sensitive adhesive composition comprising a compound of formula (3).
(3)

In Formula 3, R is 2,4-tolylene, 2,6-tolylene, 1,3-xylene, 1,4-xylene, 4,4'-diphenylmethane, hexamethylene or It is a substituent which consists of isophorone.
The pressure-sensitive adhesive composition of claim 8, further comprising a photopolymerization initiator in the pressure-sensitive adhesive composition.
An adhesive sheet formed using the pressure-sensitive adhesive composition of claim 9.
The pressure-sensitive adhesive sheet according to claim 10, wherein the pressure-sensitive adhesive composition is crosslinked and peeled off by radiation.
The adhesive sheet according to claim 10 or 11, which is used for semiconductor wafer processing.

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