TWI678409B - Cutting tape - Google Patents

Abstract

The present invention provides a dicing tape capable of suppressing scattering and chipping of a wafer in a dicing step even for a small and thin electronic component, and making it easy to pick up and less likely to generate adhesive residue. According to the present invention, there is provided a dicing tape formed by laminating an adhesive layer composed of an adhesive composition on a base film, wherein the adhesive composition contains a (meth) acrylate 100 parts by mass of a copolymer, 5 to 250 parts by mass of a photopolymerizable compound, 0.1 to 20 parts by mass of a curing agent, and 0.1 to 20 parts by mass of a photopolymerization initiator. The (meth) acrylate copolymer contains methyl (meth) acrylate The unit is 35 to 85% by mass, the 2-ethylhexyl (meth) acrylate unit is 10 to 60% by mass, the monomer unit having a carboxyl group is 0.5 to 10% by mass, and the monomer unit having a hydroxyl group is 0.05 to 5% by mass. The photopolymerizable compound is a urethane acrylate oligomer having a weight average molecular weight of 4,000 to 8,000 and an unsaturated double bond functional group of 10 to 15, and the thickness of the adhesive layer is 3 to 7 μm.

Description

Cutting tape

The present invention relates to a dicing tape used in a manufacturing step of an electronic component.

After the dicing tape is attached to the semiconductor wafer or the substrate, the semiconductor wafer or the substrate undergoes various steps such as singulation (cutting) into small component pieces, extension (expansion) of the dicing tape, and peeling (picking up) the small component pieces from the dicing tape. For the dicing tape used in these steps, it is desirable to have sufficient adhesion to the component pieces (wafers) formed in the dicing step, and at the same time, the adhesive force is reduced to the extent that no adhesive residue is generated during the pickup step.

As a dicing tape, there is a dicing tape in which an adhesive layer that causes polymerization and curing reaction due to ultraviolet rays or the like is coated on a base film that is transmissive to active light rays such as ultraviolet rays and / or electron beams. This dicing tape adopts a method in which, after the dicing step, the adhesive layer is irradiated with ultraviolet rays or the like to polymerize and cure the adhesive layer to reduce the adhesive force, and then pick up the divided wafer.

As such a dicing tape, Patent Literature 1 and Patent Literature 2 disclose a dicing tape which is coated on the surface of a base film with an intramolecular material containing a three-dimensional network formed by, for example, active light. An adhesive formed from a compound (multifunctional oligomer) having a photopolymerizable unsaturated double bond.

[Existing technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2006-049509

[Patent Document 2] Japanese Patent Laid-Open No. 2007-246633

In recent years, with the miniaturization and thickness reduction of electronic components, wafer scattering and chipping (wafer defects) are likely to occur during the dicing step of a semiconductor wafer or a substrate, and this has become a cause of a decrease in yield.

Therefore, the main object of the present invention is to provide a dicing tape which can suppress the scattering and chipping of a wafer in a dicing step even if it is a small and thin electronic component, and is easy to pick up and hardly cause residues.

According to the present invention, there is provided a dicing tape formed by laminating an adhesive layer composed of an adhesive composition on a base film, wherein the adhesive composition contains a (meth) acrylate 100 parts by mass of copolymer, 5 to 250 parts by mass of photopolymerizable compound, 0.1 of curing agent 20 to 20 parts by mass and 0.1 to 20 parts by mass of a photopolymerization initiator, the (meth) acrylate copolymer contains 35 to 85% by mass of methyl (meth) acrylate units, and 2-ethylhexyl (meth) acrylate The ester unit is 10 to 60% by mass, the monomer unit having a carboxyl group is 0.5 to 10% by mass, and the monomer unit having a hydroxyl group is 0.05 to 5% by mass. The photopolymerizable compound has a weight average molecular weight (weight average molecular weight) of 4000 to 8000 urethane acrylate oligomers having 10 to 15 unsaturated double bond functional groups, and the thickness of the adhesive layer is 3 to 7 μm.

In general, if the thickness of the adhesive layer is reduced, chipping is unlikely to occur, but the adhesive force is reduced and wafer scattering is liable to occur. In addition, if the composition of the adhesive is adjusted in order to suppress the occurrence of scattering of wafers, problems such as chipping easily, poor pick-up property, and adhesive residue easily occur. Therefore, in the past, it has been difficult to effectively suppress chipping, wafer scattering, and adhesive residue, and to improve pickup properties.

The present inventors have conducted intensive research in order to obtain a dicing tape excellent in all of these points, and as a result, have found that when an adhesive layer having a thickness of 3 to 7 μm is formed using an adhesive having a specific composition, it is possible to effectively suppress cracking, The wafer was scattered and the glue remained at the same time, so that the pickup property was good, and the present invention was completed.

Preferably, the curing agent is a polyfunctional isocyanate curing agent or a polyfunctional epoxy curing agent.

Preferably, the adhesive force to the mirror surface of the silicon wafer measured in accordance with JISZ0237 of the dicing tape is 5.0 N / 20 mm or more.

According to another aspect of the present invention, a method for manufacturing an electronic component is provided. The method includes the following steps: (a) an attaching step, attaching a dicing tape to a semiconductor wafer or a substrate and a ring frame; (b) a dicing step, The semiconductor wafer or substrate is cut to form a semiconductor wafer or semiconductor component; (c) the light irradiation step irradiates the dicing tape with active light; (d) an expansion step, in order to increase the interval between the semiconductor wafer or semiconductor component, The dicing tape is stretched; and (e) a pickup step of picking up a semiconductor wafer or a semiconductor component from the dicing tape, the dicing tape being the dicing tape described above.

According to the present invention, it is possible to provide a dicing tape capable of suppressing scattering and chipping of a wafer in a dicing step even if it is a small and thin electronic component, and it is easy to pick up, and it is difficult to generate adhesive residue.

Hereinafter, preferred embodiments for carrying out the present invention will be described. It should be noted that the embodiment described below represents an example of a representative embodiment of the present invention, and the scope of the present invention is not interpreted too narrowly.

<Adhesive composition>

The adhesive composition for forming the adhesive layer of the dicing tape of the present invention contains 100 parts by mass of a (meth) acrylate copolymer, 5 to 250 parts by mass of a photopolymerizable compound, and 0.1 to 20 parts by mass of a curing agent. And 0.1 to 20 parts by mass of a photopolymerization initiator.

((Meth) acrylate copolymer)

The (meth) acrylic acid ester copolymer contains 35 to 85 mass% of methyl (meth) acrylate units (preferably 45 to 75 mass%, more preferably 50 to 70 mass%, and still more preferably 55 to 65 mass%) 2, 10% to 60% by mass of 2-ethylhexyl (meth) acrylate unit (preferably 20 to 50% by mass, more preferably 25 to 45% by mass, still more preferably 30 to 40% by mass), a monomer having a carboxyl group 0.5 to 10% by mass (preferably 2 to 7% by mass, more preferably 3 to 6% by mass, still more preferably 4 to 5% by mass), 0.05 to 5% by mass (preferably 0.1) (~ 3 mass%, more preferably 0.2 to 2 mass%, still more preferably 0.3 to 1 mass%, and still more preferably 0.4 to 0.7 mass%). When the (meth) acrylic acid ester copolymer is composed of such a monomer unit, even if the thickness of the adhesive layer is as small as 3 to 7 μm, a dicing tape having a sufficiently high adhesive force can be obtained. In addition, as for the adhesive force of a dicing tape, it is preferable that the adhesive force with respect to the mirror surface of a silicon wafer measured based on JIS Z 0237 is 5.0 N / 20mm or more.

Examples of the monomer having a carboxyl group include (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, acrylamide N-glycolic acid, and cinnamic acid. Among them, (meth) )acrylic acid.

Examples of the monomer having a hydroxyl-containing functional group include 2-hydroxyethyl (meth) acrylate, (formaldehyde) 2-hydroxypropyl acrylate and 2-hydroxybutyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate is preferred.

(Photopolymerizable compound)

The mixing amount of the photopolymerizable compound is 5 to 250 parts by mass, and preferably 40 to 200 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer. When the mixing amount of the photopolymerizable compound is decreased, the releasability of the dicing tape after irradiation with active light such as ultraviolet rays is reduced, and a pick-up failure of a semiconductor wafer is likely to occur. On the other hand, if the mixing amount of the photopolymerizable compound is increased, the adhesive force is excessively reduced by the light irradiation step, and the wafer is loosened in the picking step, which is a cause of lowering productivity.

The photopolymerizable compound usable in the present invention is a urethane acrylate oligomer having a weight average molecular weight of 4000 to 8000 and an unsaturated double bond functional group of 10 to 15. If the weight average molecular weight is small, the side of the pressure-sensitive adhesive is soft, so that chipping is likely to occur. If the weight average molecular weight is large, the adhesion to the adherend is reduced, and wafer scattering is liable to occur. If the number of unsaturated double bond functional groups is small, the curability of the adhesive after ultraviolet irradiation or the like is reduced, and pick-up defects are liable to occur. If the number of unsaturated double bond functional groups is large, the adhesive after ultraviolet radiation or the like is excessively cured, Loose wafer. In addition, when a urethane acrylate oligomer is used, since it has excellent adhesion and flexibility to the base film, there is an advantage that residues are not easily generated during picking up.

The urethane acrylate oligomer can be obtained by reacting a (meth) acrylate having a hydroxyl group with a terminal isocyanate polyurethane prepolymer such as a polyester type or a polyether type. The cyanate ester prepolymer is obtained by reacting a polyol compound and a polyisocyanate compound.

As the polyol compound, for example, ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, pentanediol, glycerol, trimethylolpropane, and trihydroxyol are used. Methylethane, pentaerythritol, etc. As the polyisocyanate compound, for example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylene diisocyanate, and 1,4-xylene are used. Diisocyanate, diphenylmethane 4,4-diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, isoflurone diisocyanate Acid grease and so on. Examples of the (meth) acrylate having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol (meth) acrylate, Pentaerythritol triacrylate, glycidyl di (meth) acrylate, dipentaerythritol monohydroxy pentaacrylate, and the like.

(Hardener)

The mixing amount of the curing agent is 0.1 to 20 parts by mass, and preferably 1 to 10 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer. If the mixing amount of the curing agent is reduced, residual glue is liable to occur. On the other hand, when the mixing amount of the curing agent is increased, insufficient adhesive strength or looseness of the wafer occurs, which is a cause of lowering productivity.

Examples of the curing agent include a polyfunctional isocyanate curing agent, a polyfunctional epoxy curing agent, an aziridine compound, and a melamine compound. Among them, a polyfunctional isocyanate curing agent and a polyfunctional epoxy curing agent are preferred. By using a polyfunctional epoxy curing agent or a polyfunctional isocyanate curing agent as at least a part of the curing agent, it is possible to selectively react a functional group having a carboxyl group-containing monomer to make it This reduces the amount of the monomer having a carboxyl group-containing functional group after curing.

Examples of the polyfunctional isocyanate curing agent include an aromatic polyisocyanate curing agent, an aliphatic polyisocyanate curing agent, and an alicyclic polyisocyanate curing agent.

The aromatic polyisocyanate is not particularly limited, and examples thereof include 1,3-benzenediisocyanate, 4,4'-diphenyldiisocyanate, and 1,4-benzenediisocyanate. , 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate , 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate , 4,4 ', 4 "-triphenylmethane triisocyanate, ω, ω'-diisocyanate-1,3-dimethylbenzene, ω, ω'-diisocyanate- 1,4-dimethylbenzene, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3 -Tetramethylxylylene diisocyanate and the like.

The aliphatic polyisocyanate is not particularly limited, and examples thereof include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, and pentamethylene diisocyanate. Cyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecyl diisocyanate Grease, and 2,4,4-trimethylhexamethylene diisocyanate.

The alicyclic polyisocyanate is not particularly limited, and examples thereof include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, and 1,3-cyclopentane diisocyanate. Cyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2 , 6-cyclohexyl Alkane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanate methyl) cyclohexane, and 1,4-bis (iso Cyanate methyl) cyclohexane.

Among the polyisocyanates, 1,3-benzenediisocyanate, 4,4'-diphenyldiisocyanate, 1,4-benzenediisocyanate, and 4,4'- Diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, hexamethylene di Isocyanate.

Multifunctional epoxy curing agents mainly refer to compounds having two or more epoxy groups and one or more tertiary nitrogen atoms. Examples include N‧N-glycidylaniline, N‧N-glycidyltoluidine, mN‧ N-glycidylaminophenyl glycidyl ether, pN‧N-glycidylaminophenyl glycidyl ether, triglycidyl isocyanurate, N‧N‧N'‧N'-tetraglycidyl Diaminodiphenylmethane, N‧N‧N'‧N'-tetraglycidyl-m-xylylene diamine, N‧N‧N'‧N'‧N "-penta glycidyl diimide Ethyltriamine, etc.

(Photopolymerization initiator)

The mixing amount of the photopolymerization initiator is 0.1 to 20 parts by mass, and preferably 1 to 10 parts by mass based on 100 parts by mass of the (meth) acrylate polymer. When the mixing amount is too small, the releasability from the dicing tape after light irradiation is reduced, and a pick-up failure of a semiconductor wafer is likely to occur. On the other hand, if the mixing amount is too large, the photopolymerization initiator will ooze out to the surface of the adhesive, and cause contamination.

As the photopolymerization initiator, benzoin, benzoin alkyl ethers, acetophenones, anthraquinones, Thiolone, ketal, benzophenone or xanthone.

Examples of benzoin include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin propyl ether.

Examples of acetophenones include acetoin alkyl ethers, acetophenone, 2,2-dimethoxy-2-acetophenone, 2,2-diethoxy-2-acetophenone, 1,1-dichloroacetophenone and so on.

Examples of anthraquinones include 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, and 1-chloroanthraquinone.

Examples of thioxanthone include 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, etc. .

Examples of ketals include acetophenone dimethyl ketal, benzyl diketal, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, Diacetamidine, β-chloroanthraquinone, etc.

Among the photopolymerization initiators, one or two or more conventionally known photopolymerization accelerators may be used in combination as necessary. As a photopolymerization accelerator, a benzoic acid type, a tertiary amine, etc. can be used. Examples of the tertiary amine include triethylamine, tetraethylpentamine, and dimethylamino ether.

(Adhesion imparting resin)

An adhesive-imparting resin may be blended in the adhesive composition. The adhesion-imparting resin is a terpene phenol resin obtained by completely or partially hydrogenating a terpene phenol resin.

The terpene phenol resin can be produced, for example, by reacting 1 mol of a terpene compound with 0.1 to 50 phenols.

Examples of terpene compounds include myrcene, allocene, basilene, α-pinene, β-pinene, dipentene, limonene, α-phellandrene, α-terpinene, and γ-terpinene. Ene, isoterpinene, 1,8-cineolin, 1,4-cineolin, α-terpineol, β-terpineol, γ-terpineol, pinene, tricyclene, pinene , Paramente, pinene and so on. Among these compounds, α-pinene, β-pinene, limonene, myrcene, allylene, and α-terpinene are particularly preferably used in the present invention.

Examples of the phenols include, but are not limited to, phenol, cresol, xylenol, catechol, resorcinol, hydroquinone, and bisphenol A.

The terpene phenol resin has a phenol ratio of about 25 to 50 mol%, but is not limited thereto.

The hydroxyl value of the completely or partially hydrogenated terpene phenol resin is preferably 50 to 250. When the hydroxyl value is less than 50, the reaction with the isocyanate-based curing agent is insufficient, and it bleeds out to the surface of the adhesive, which becomes a cause of contamination. If it exceeds 250, the viscosity increases, and a copolymer with (meth) acrylate is generated. The mixing is uneven and the picking characteristics are unstable.

The hydrogenation method is not particularly limited, and examples thereof include a method in which noble metals such as palladium, ruthenium, and rhodium are used, or those obtained by supporting them on a carrier such as activated carbon, activated alumina, and diatomaceous earth as a catalyst. In the method, the hydrogenation rate can be measured by a bromine number measurement, an iodine value measurement, or the like.

The hydrogenation rate of the completely or partially hydrogenated terpene phenol resin is preferably 30 mol% or more, and more preferably 70 mol% or more. If it is less than 30 mol%, the adhesive force cannot be sufficiently lowered due to the hindrance of the reaction of the photopolymerizable compound due to the irradiation of the active light, and thus the pick-up property is lowered.

The compounding ratio of the completely or partially hydrogenated terpene phenol resin is preferably 0.5 to 100 parts by mass, and more preferably 1.0 to 50 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer. If the fully or partially hydrogenated terpene phenol resin is 0.5 parts by mass or more, the adhesive force will not be too low, and the retention of the semiconductor wafer during dicing is maintained. If it is 100 parts by mass or less, the occurrence of pick-up defects can be suppressed.

(Additives, etc.)

Various additives such as a softener, an anti-aging agent, a filler, a conductive agent, an ultraviolet absorber, and a light stabilizer can be added to the adhesive composition.

The thickness of the adhesive layer is 3 to 7 μm, and preferably 4 to 6 μm. If the pressure-sensitive adhesive layer is too thick, chipping easily occurs. In addition, if the adhesive layer is too thin, the adhesive force becomes too low, and wafer retention during dicing may be reduced, which may cause wafer scattering or release between the ring frame and the sheet.

(Base film)

Examples of the material of the base film include ionomer resins obtained by crosslinking the following materials with metal ions: polyvinyl chloride, polyethylene terephthalate, acetic acid-vinyl acetate copolymer, Ethylene-acrylic-acrylate film, ethylene-ethyl acrylate copolymer, polyethylene, polypropylene, A propylene-based copolymer, an ethylene-acrylic acid copolymer, an ethylene- (meth) acrylic acid copolymer, an ethylene- (meth) acrylic acid- (meth) acrylate copolymer, and the like. The base film may be a mixture or copolymer of these resins, or may be a laminate of a film or a sheet made of these resins.

The material of the base film is preferably an ionomer resin. As the ionomer resin, an ionomer obtained by crosslinking a copolymer having an ethylene unit, a methacrylic acid unit, and an (meth) acrylic acid alkyl ester unit with metal ions such as Na ⁺ , K ⁺ , and Zn ^{2+ is} used. Bioresin is preferred because it has a significant chip-suppressing effect.

The base film may be a single-layer or multi-layer film or sheet made of the above-mentioned materials, or may be a laminate of films or the like made of different materials. The thickness of the base film is 50 to 200 μm, and preferably 70 to 150 μm.

The base film is preferably subjected to an antistatic treatment. Examples of the antistatic treatment include a treatment in which an antistatic agent is added to the base film, a treatment in which an antistatic agent is coated on the surface of the base film, and a treatment based on corona discharge.

As the antistatic agent, for example, a quaternary ammonium salt monomer or the like can be used. Examples of the quaternary ammonium salt monomer include quaternary chlorinated dimethylaminoethyl (meth) acrylate, quaternary chlorinated diethylaminoethyl (meth) acrylate, and methyl (meth) acrylate Ethylaminoethyl quaternary chloride, p-dimethylaminostyrene quaternary chloride, and p-diethylaminostyrene quaternary chloride. Among these, quaternary chlorinated dimethylaminoethyl methacrylate is preferred.

The method of using the sliding agent and the antistatic agent is not particularly limited. For example, an adhesive may be coated on one side of the base film, and a sliding agent and / or an antistatic agent may be coated on the back surface. The sliding agent and / or the antistatic agent may also be applied. The resin is mixed into a base film to form a sheet.

The adhesive may be laminated on one side of the base film, and the other side may be an embossed surface having an average surface roughness (Ra) of 0.3 to 1.5 μm. By providing an embossed surface on the machine side of the expansion device, the substrate film can be easily expanded in the expansion step after cutting.

(Slip agent)

In order to improve the expandability after cutting, a sliding agent may be applied to the non-contact surface of the adhesive of the base film, or a sliding agent may be mixed into the base film.

The sliding agent is not particularly limited as long as it reduces the friction coefficient between the cutting tape and the expansion device, and examples thereof include organic silicon compounds such as silicone resin or (modified) silicone oil, fluorine resin, hexagonal boron nitride, and carbon black. And molybdenum disulfide. These friction reducing agents may be mixed with a plurality of components. In order to manufacture electronic components in a clean room, an organic silicon compound or a fluororesin is preferably used. Among the organosilicon compounds, in particular, the copolymer having the organosilicon macromonomer unit has good compatibility with the antistatic layer and can achieve a balance between antistatic properties and expandability, and is therefore preferably used.

Specific steps of the method for manufacturing an electronic component according to the present invention will be described in order.

(1) Attachment steps

First, in the attaching step, a dicing tape is attached to a semiconductor wafer or a substrate and a ring frame. Semiconductor wafers can be silicon wafers, gallium nitride wafers, silicon carbide wafers, sapphire wafers, and other conventional wafers. The substrate may be a general-purpose substrate such as a package substrate in which a wafer is sealed with a resin, an LED package substrate, or a ceramic substrate.

(2) Cutting step

In the dicing step, a semiconductor wafer or a substrate is cut to form a semiconductor wafer or a semiconductor component.

(3) Light irradiation step

In the light irradiation step, the dicing tape is irradiated with active light such as ultraviolet rays or electron beams. The active light is preferably radiated from the substrate film side. As the ultraviolet light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp can be used. Alternatively, an electron beam may be used instead of ultraviolet rays, and as the electron beam light source, alpha rays, beta rays, and gamma rays may be used.

When the light is irradiated, the pressure-sensitive adhesive layer is three-dimensionally networked and cured, and the adhesive force of the pressure-sensitive adhesive layer is reduced. At this time, as described above, the dicing tape according to the present invention does not excessively adhere to a semiconductor wafer or a substrate even when heated, and thus sufficiently low adhesive force can be obtained by irradiation of ultraviolet rays or the like.

(4) Expansion and picking steps

In the expansion and picking step, in order to increase the interval between semiconductor wafers or semiconductor components, the dicing tape is stretched, and the wafer or component is pushed up with a pin or the like. Thereafter, a vacuum chuck or a pneumatic chuck or the like attracts the wafer or the component, peels it from the adhesive layer of the dicing tape, and picks it up. this In this case, since the dicing tape according to the present invention can sufficiently reduce the adhesive force by irradiation with ultraviolet rays or the like, peeling between the wafer or the component and the adhesive layer becomes easy, good pick-up properties are obtained, and no Residual glue and other undesirable phenomena.

<Manufacture of dicing tape>

As a method of forming an adhesive layer on a base film to obtain a dicing tape, for example, a method such as using a gravure coater, a comma coater, a bar coater, a blade coater, or a roll coater, A method in which an adhesive is directly applied to a base film; or a method in which an adhesive is applied to a release film and dried, and then bonded to the base film. The adhesive can also be printed on the substrate film by convex printing, gravure printing, offset printing, flexographic printing, offset printing or screen printing.

The dicing tape of the present invention is preferably used for affixing an electronic component assembly called a work in a cutting step or a back grinding step that is an electronic component manufacturing step.

[Example]

An adhesive composition and a dicing tape according to Example ‧ Comparative Example were produced according to the following formulation. The main compounding ingredients and the results of each experimental example are shown in Tables 1 to 3.

The numerical values of the composition in Tables 1 to 3 represent parts by mass. The numerical values of the photopolymerizable compound, the curing agent, and the photopolymerization initiator represent parts by mass when the (meth) acrylate copolymer is 100 parts. The details of the base film, the photopolymerizable compound, the curing agent, and the photopolymerization initiator are as follows.

The weight average molecular weight is a value measured by gel permeation chromatography (GPC) as a polystyrene-equivalent weight average molecular weight. Specifically, it is as follows.

Device: GPC-8020 SEC system (manufactured by Tosoh Corporation)

Column (column): TSK Guard HZ-L + HZM-N 6.0 × 150mm × 3

Flow: 0.5ml / min

Detector: RI-8020

Concentration: 0.2wt / Vol%

Injection volume: 20 μL

Column temperature: 40 ° C

System temperature: 40 ° C

Solvent: THF

Standard curve: Prepared using standard polystyrene (manufactured by PL), and the weight average molecular weight (Mw) is expressed in terms of polystyrene.

<Substrate film>

‧Resin film A: An ionomer resin film with a thickness of 80 μm, which is mainly composed of a Zn salt of an ethylene-methacrylic acid-2-methylpropyl acrylate copolymer. MFR 2.8 g / 10 min (JIS K7210 method, 210 ° C), manufactured by Mitsui DuPont Polychemicals Co., Ltd. (commercially available product).

<Photopolymerizable compound>

‧Photopolymerizable compound A: A compound obtained by reacting an isocyanate of hexamethylene diisocyanate with a hydroxyl-containing acrylate containing dipentaerythritol pentaacrylate as a main component. The weight-average molecular weight is 7500, and a urethane acrylate oligomer (synthetic product) with an unsaturated double bond functional group of 10.

‧Photopolymerizable compound B: Polyurethane acrylate oligomer (synthetic product) having a weight-average molecular weight of 4200 and an unsaturated double bond functional group of 10 synthesized by the same method as the photopolymerizable compound A

‧Photopolymerizable compound C: Polyurethane acrylate oligomer (synthetic product) having a weight average molecular weight of 2100 and an unsaturated double bond functional group of 10 synthesized by the same method as the photopolymerizable compound A

‧Photopolymerizable compound D: Polyurethane acrylate oligomer (synthetic product) having a weight-average molecular weight of 10300 and unsaturated double bond functional groups of 10 synthesized by the same method as photopolymerizable compound A

‧Photopolymerizable compound E: A compound obtained by reacting an isocyanate of a trimer of isophorone diisocyanate with a hydroxyl-containing acrylate containing dipentaerythritol pentaacrylate as a main component, and a weight average molecular weight A urethane acrylate oligomer (synthetic product) of 4900 and 15 unsaturated double bond functional groups.

In addition, a photopolymerizable compound is prepared by the well-known method described in Unexamined-Japanese-Patent No. 61-42529.

<Curing agent>

‧Curing agent A: 2,4-toluene diisocyanate trimethylolpropane adduct (commercial product)

‧Curing agent B: Trimethylolpropane adduct of hexamethylene diisocyanate (commercial product)

‧Curing agent C: N, N, N ', N'-tetraglycidyl-m-xylylenediamine (commercial product)

<Photopolymerization initiator>

‧Photopolymerization initiator A: 1-hydroxycyclohexylphenyl ketone (commercial product)

‧Photopolymerization initiator B: benzyl dimethyl ketal (commercial product)

(1) Adhesion

According to JIS Z 0237; 2009, a tensile tester (manufactured by A & D Co., Ltd., RTG-1210) was used to measure the dicing tape attached to the mirror surface of a silicon wafer by a 180 ° peel method at 20 ° C and relative humidity after 20 minutes. Adhesion at 50%. The stretching speed was 300 mm / min, and the size of the cutting tape was 250 mm × 20 mm. In addition, as the mirror surface of the silicon wafer, a mirror surface prepared in accordance with JIS H 0614 was used.

(2) Evaluation of wafer retention, pick-up, and chipping

The obtained dicing tape was bonded to a silicon wafer having a diameter of 8 inches and a thickness of 0.15 mm and a ring frame on which a dummy circuit pattern was formed. After bonding for 20 minutes, ultraviolet rays of 150 mJ / cm ² were irradiated with a high-pressure mercury lamp, and then cutting and picking steps were performed.

The conditions of the cutting step are as follows.

Cutting device: DAD341 by DISCO

Cutting blade: NBC-ZH205O-27HEEE, manufactured by DISCO

Cutting blade shape: 55.56mm outer diameter, 35μm blade width, 19.05mm inner diameter

Cutting blade speed: 40000rpm

Cutting blade feed speed: 100mm / s

Cutting size: 1.0mm square

Cut-in amount in cutting tape: 30 μm

Cutting water temperature: 25 ℃

Cutting water volume: 1.0 l / min

The conditions of the picking step are as follows.

Pickup device: CAP-300II by Canon Machinery

Expansion: 8mm

Pin shape: 70μmR

Number of pins: 1

Needle push-up height: 0.3mm

In the cutting step and the pickup step, the following evaluations were performed.

(2-1) Wafer retention

Wafer retention was evaluated on the basis of the residual rate of the semiconductor wafer in which the semiconductor wafer was held on the dicing tape after the dicing step.

◎ (Excellent): The chip scattering is less than 5%

○ (Good): The chip scattering is more than 5% and less than 10%

× (impossible): The scattering of the wafer is more than 10%

(2-2) Picking

The pick-up property was evaluated on the basis of the ratio of the semiconductor wafer that can be picked up in the pick-up step.

◎ (Excellent): The picking success rate of the wafer is above 95%

○ (Good): The picking success rate of the wafer is more than 80% and less than 95%

× (impossible): The success rate of wafer picking is less than 80%

(2-3) Chipping

For cracking, randomly select 50 picked wafers, observe the four sides of the back of the wafer with a 500-fold microscope, and evaluate the size of the largest defect in the center direction according to the following criteria.

◎ (Excellent): The defect size is less than 25 μm

○ (Good): The size of the defect is 25 μm or more and less than 50 μm

× (impossible): the size of the defect is 50 μm or more

(3) Pollution

The dicing tape was affixed to the mirror surface of the silicon wafer. After 20 minutes, 150 mJ / cm ² of ultraviolet light was irradiated with a high-pressure mercury lamp, and then the dicing tape was peeled off. The number of particles of 0.28 μm or more remaining on the mirror surface (attachment surface) of the silicon wafer was measured with a particle counter.

◎ (Excellent): 500 or less particles

(Good): The number of particles is 501 or more and less than 2,000.

× (impossible): 2,000 or more particles.

(4) the chip is loose

Wafer looseness is evaluated according to the following criteria based on the ratio of the looseness of the semiconductor wafer adjacent to the semiconductor wafer to be picked up in the pick-up step due to the impact of the pin jack.

◎ (Excellent): The chip looseness is less than 1%

○ (Good): The chip looseness is more than 1% and less than 3%

× (impossible): wafer looseness is more than 3%

(Inspection)

As shown in Examples and Comparative Examples in Tables 1 to 3, in all Examples in which an adhesive layer having a thickness of 3 to 7 μm was formed using an adhesive having a specific composition, the overall judgment was ○ or ◎. On the other hand, in all comparative examples in which the composition of the pressure-sensitive adhesive or the thickness of the pressure-sensitive adhesive layer was out of a predetermined range, the overall judgment was ×. From these results, it was confirmed that when the dicing tape of the present invention is used, chipping, wafer scattering, and adhesive residue can be effectively suppressed, and at the same time, pick-up properties can be improved.

Further detailed analysis is described below.

In Comparative Example 1, the number of methyl (meth) acrylate units was too small, and contamination was poor.

In Comparative Example 2, since there were too many methyl (meth) acrylate units, wafer retention was poor, and the wafer was easily loosened.

In Comparative Example 3, since the number of monomer units having a carboxyl group was too small, wafer retention was poor.

In Comparative Example 4, since there are too many monomer units having a carboxyl group, pickup properties and contamination properties are poor.

In Comparative Example 5, since there are too few monomer units having a hydroxyl group, contamination is poor.

In Comparative Example 6, since there are too many monomer units having a hydroxyl group, the wafer is easily loosened.

In Comparative Example 7, since the amount of the photopolymerizable compound was too small, the wafer holding property and pick-up property were poor.

In Comparative Example 8, since there were too many photopolymerizable compounds, contamination was poor, and the wafer was easily loosened.

In Comparative Example 9, since the weight-average molecular weight of the photopolymerizable compound was too small, chipping easily occurred.

In Comparative Example 10, the weight-average molecular weight of the photopolymerizable compound was too large, so the wafer retention difference.

In Comparative Example 11, since the curing agent was too small, the contamination property was poor.

In Comparative Example 12, since the curing agent was too much, the wafer retention and contamination properties were poor, and the wafer was easily loosened.

In Comparative Example 13, the photopolymerization initiator was too small, so the pick-up property was poor.

In Comparative Example 14, since the photopolymerization initiator was too much, contamination was poor, and the wafer was easily loosened.

In Comparative Example 15, since the adhesive layer was too thin, the wafer retention was poor, and the wafer was easily loosened.

In Comparative Example 16, since the pressure-sensitive adhesive layer was too thick, chipping easily occurred and the pickup property was poor.

Claims (4)

A dicing tape formed by laminating an adhesive layer composed of an adhesive composition on a base film, wherein the adhesive composition contains 100 parts by mass of a (meth) acrylate copolymer 5 to 250 parts by mass of a photopolymerizable compound, 0.1 to 20 parts by mass of a curing agent, and 0.1 to 20 parts by mass of a photopolymerization initiator, the (meth) acrylate copolymer contains 35 (meth) acrylate units 35 ~ 85 mass%, 2-ethylhexyl (meth) acrylate unit 10 to 60 mass%, monomer unit having a carboxyl group 0.5 to 10 mass%, and monomer unit having a hydroxyl group 0.05 to 5 mass%. The photopolymerizable compound is a urethane acrylate oligomer having a weight average molecular weight of 4000 to 8000 and an unsaturated double bond functional group of 10 to 15, and the thickness of the adhesive layer is 3 to 7 μm. The dicing tape according to claim 1, wherein the curing agent is a polyfunctional isocyanate curing agent or a polyfunctional epoxy curing agent. The dicing tape according to claim 1 or 2, wherein an adhesive force of the dicing tape to a mirror surface of a silicon wafer measured in accordance with JIS Z 0237 is 5.0 N / 20 mm or more. A method for manufacturing an electronic component, comprising the following steps: (a) an attaching step, attaching a dicing tape to a semiconductor wafer or a substrate and a ring frame; (b) a dicing step, dicing the semiconductor wafer or A substrate to form a semiconductor wafer or a semiconductor component; (c) a light irradiation step to irradiate the dicing tape with active light; (d) an expansion step to expand the gap between the semiconductor wafer or the semiconductor component; Performing stretching; and (e) a pickup step of picking up a semiconductor wafer or a semiconductor component from the dicing tape, wherein the dicing tape is the dicing tape according to any one of claims 1 to 3.