TW201636408A - Dicing tape - Google Patents

Abstract

Provided is a dicing tape with which it is possible to minimize chip scattering and chipping during a dicing step, with which pickup can easily be performed, and with which adhesive residues are unlikely to remain even for small and thin electronic components. The present invention provides a dicing tape obtained by layering an adhesive layer comprising an adhesive composition on a substrate film, wherein the dicing tape is characterized in that: the adhesive composition contains 100 parts by mass of a (meth)acrylic acid ester copolymer, 5-250 parts by mass of a photopolymerizing compound, 0.1-20 mass parts of a curing agent, and 0.1-20 mass parts of a photopolymerizing initiator, the (meth)acrylic acid ester copolymer containing 35-85% by mass of a methyl (meth)acrylate unit, 10-60% by mass of a 2-ethylhexyl (meth)acrylate unit, 0.5-10% by mass of a monomer unit having a carboxyl group, and 0.05-5% by mass of a monomer unit having a hydroxyl group, the photopolymerizing compound being a urethane acrylate oligomer having a weight-average molecular weight of 4,000-8,000 and 10-15 unsaturated double-bond functional groups, and the thickness of the adhesive layer being 3-7 [mu]m.

Description

Cutting tape

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

After bonding the dicing tape, the semiconductor wafer or substrate will undergo various steps such as dividing (cutting) into small pieces of the element, extending (expanding) the dicing tape, and peeling off the dicing tape from the dicing tape. For the dicing tape used in these steps, it is desirable to have sufficient adhesion to the element pieces (wafers) formed in the cutting step, while the adhesion force is reduced to the extent that no residual glue is generated at the pickup step.

As the dicing tape, there is a dicing tape which is coated with a pressure-sensitive adhesive layer which is subjected to a polymerization curing reaction by ultraviolet rays or the like on a substrate film which is transparent to active light such as ultraviolet rays and/or electron beams. This dicing tape is a method in which after the dicing step, the pressure-sensitive adhesive layer is irradiated with ultraviolet rays or the like to polymerize and cure the pressure-sensitive adhesive layer to lower the adhesive force, and then the divided wafer is picked up.

As such a dicing tape, Patent Document 1 and Patent Document 2 disclose a dicing tape which is coated on a surface of a substrate film and which contains, for example, three-dimensional network due to active light rays. A binder formed of a compound (polyfunctional oligomer) having a photopolymerizable unsaturated double bond.

[Prior Art Literature] [Patent Literature]

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

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

In recent years, with the miniaturization and thinning of electronic components, wafer scattering and chipping (wafer defect) are likely to occur in the semiconductor wafer or substrate dicing step, which is a cause of a decrease in yield.

Accordingly, it is a primary object of the present invention to provide a dicing tape which can suppress scattering and cracking of a wafer in a cutting step even in a small and thin electronic component, which is easy to pick up and which is less likely to cause residual glue.

According to the present invention, there is provided a dicing tape which is formed by laminating a pressure-sensitive adhesive layer composed of an adhesive composition on a substrate film, characterized in that the pressure-sensitive adhesive composition contains (meth) acrylate 100 parts by mass of the copolymer, 5 to 250 parts by mass of the photopolymerizable compound, and 0.1 curing agent ~20 parts by mass and 0.1 to 20 parts by mass of the photopolymerization initiator, and the (meth) acrylate copolymer contains 35 to 85% by mass of methyl (meth) acrylate unit and 2-ethyl group (meth) acrylate 10 to 60% by mass of the ester unit, 0.5 to 10% by mass of the monomer unit having a carboxyl group, and 0.05 to 5% by mass of the monomer unit having a hydroxyl group, and the photopolymerizable compound has a weight average molecular weight (weight average molecular weight) of 4,000. A urethane acrylate oligomer having 8000 and an unsaturated double bond functional group of 10 to 15, and the pressure-sensitive adhesive layer has a thickness of 3 to 7 μm.

In general, when the thickness of the pressure-sensitive adhesive layer is made small, cracking is less likely to occur, but the adhesive strength is small and wafer scattering is likely to occur. Further, when the composition of the pressure-sensitive adhesive is adjusted in order to suppress the occurrence of wafer scattering, it is likely to cause a problem that cracking is likely to occur, pickup property is deteriorated, or residual glue is likely to occur. Therefore, in the past, it has been difficult to effectively suppress the cracking, the wafer scattering, and the residual glue while making the pickup property good.

The present inventors have conducted intensive studies in order to obtain a dicing tape which is excellent in these aspects, and as a result, it has been found that when a pressure-sensitive adhesive layer having a thickness of 3 to 7 μm is formed using a binder having a specific composition, cracking can be effectively suppressed. The present invention has been completed by the fact that the wafer is scattered and remnulated while the pickup property is good.

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

Preferably, the adhesive tape of the dicing tape according to JIS Z0237 has a bonding strength to the mirror surface of the ruthenium wafer of 5.0 N/20 mm or more.

According to another aspect of the present invention, a method of manufacturing an electronic component is provided, the method comprising the steps of: (a) attaching a step of attaching a dicing tape to a semiconductor wafer or substrate and a ring frame; and (b) cutting step, Cutting the semiconductor wafer or substrate to form a semiconductor wafer or a semiconductor component; (c) irradiating the dicing tape with active light rays by a light irradiation step; (d) expanding step of expanding the interval between the semiconductor wafer or the semiconductor component The dicing tape is stretched; and (e) the picking process, the semiconductor wafer or the semiconductor component is picked up from the dicing tape, and the dicing tape is the dicing tape described above.

According to the present invention, it is possible to provide a dicing tape capable of suppressing scattering and cracking of a wafer in a cutting step even in a small-sized and thin electronic component, which is easy to pick up and which is less likely to cause residual glue.

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

<Adhesive Composition>

The pressure-sensitive adhesive composition used for forming the pressure-sensitive 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 the photopolymerization initiator is 0.1 to 20 parts by mass.

((meth)acrylate copolymer)

The (meth) acrylate copolymer contains 35 to 85% by mass of methyl (meth) acrylate unit (preferably 45 to 75% by mass, more preferably 50 to 70% by mass, still more preferably 55 to 65% by mass) The 2-ethylmethyl (meth)acrylate unit is 10 to 60% by mass (preferably 20 to 50% by mass, more preferably 25 to 45% by mass, still more preferably 30 to 40% by mass), and a single group having a carboxyl group The volume unit is 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), and the monomer unit having a hydroxyl group is 0.05 to 5% by mass (preferably 0.1). ～3% by mass, more preferably 0.2 to 2% by mass, still more preferably 0.3 to 1% by mass, still more preferably 0.4 to 0.7% by mass. When the (meth) acrylate copolymer is composed of such a monomer unit, a dicing tape having a sufficiently high adhesive force can be obtained even if the thickness of the pressure-sensitive adhesive layer is as small as 3 to 7 μm. In addition, the adhesive force with respect to the dicing tape is preferably 5.0 N/20 mm or more with respect to the mirror surface of the enamel wafer measured in accordance with JIS Z 0237.

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, and the like, preferably (methyl) )acrylic acid.

As a monomer having a hydroxyl group-containing functional group, for example, 2-hydroxyethyl (meth)acrylate, (A) 2-hydroxypropyl acrylate, and 2-hydroxybutyl (meth) acrylate, preferably 2-hydroxyethyl (meth) acrylate.

(photopolymerizable compound)

The amount of the photopolymerizable compound to be mixed is 5 to 250 parts by mass, preferably 40 to 200 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer. When the amount of the photopolymerizable compound is reduced, the peeling property of the dicing tape after irradiation with active light such as ultraviolet rays is lowered, and the pickup failure of the semiconductor wafer is likely to occur. On the other hand, when the mixing amount of the photopolymerizable compound is increased, the adhesive strength is excessively lowered by the light irradiation step, and the wafer is loosened in the pickup step, which causes a decrease in productivity.

The photopolymerizable compound usable in the present invention 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. When the weight average molecular weight is small, the binder is soft and is likely to be cracked. When the weight average molecular weight is large, the adhesion to the adherend is lowered, and wafer scattering is likely to occur. When the number of unsaturated double bond functional groups is small, the curability of the adhesive after irradiation with ultraviolet rays or the like is lowered, and picking failure is likely to occur. When the number of unsaturated double bond functional groups is large, the curing of the adhesive after irradiation with ultraviolet rays or the like is excessive. The wafer is loosened. Further, when a urethane acrylate oligomer is used, since it is excellent in adhesion to a base film and flexibility, it has an advantage that it is less likely to generate residual glue at the time of 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, and the terminal isocyanate is polymerized. The cyanoester prepolymer is obtained by reacting a polyol compound with a polyvalent isocyanate compound.

As the polyol compound, for example, ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, pentanediol, glycerin, trimethylolpropane, trihydroxyl is used. Methyl ethane, pentaerythritol, and the like. As the polyvalent isocyanate compound, for example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene is used. Diisocyanate, diphenylmethane 4,4-diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate Acid fat and so on. Further, examples of the (meth) acrylate having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and polyethylene glycol (meth)acrylate. Pentaerythritol triacrylate, glycidyl di(meth)acrylate, dipentaerythritol monohydroxypentaacrylate, and the like.

(Hardener)

The amount of the curing agent to be added is 0.1 parts by mass to 20 parts by mass, preferably 1 part by mass to 10 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer. If the amount of the curing agent is reduced, the residual glue is likely to be generated. On the other hand, when the amount of the curing agent is increased, the insufficient adhesion or the looseness of the wafer occurs, which causes a decrease in productivity.

Examples of the curing agent include a polyfunctional isocyanate curing agent, a polyfunctional epoxy curing agent, an aziridine compound, and a melamine compound, and a polyfunctional isocyanate curing agent and a polyfunctional epoxy curing agent are preferable. By using a polyfunctional epoxy curing agent or a polyfunctional isocyanate curing agent as at least a part of the above curing agent, it is possible to selectively react a functional group-containing monomer having a carboxyl group to cause it to react It is reduced, and thus the amount of the monomer having a carboxyl group-containing functional group after curing can be adjusted.

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-benzene diisocyanate, 4,4'-diphenyl diisocyanate, and 1,4-benzene diisocyanate. , 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 or the like.

The aliphatic polyisocyanate is not particularly limited, and examples thereof include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, and pentamethylene diiso isomer. Cyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate Lipid, 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 diiso isomer. Cyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2 ,6-ring Alkyl diisocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, and 1,4-double (iso) Cyanate methyl) cyclohexane.

Among the polyisocyanates, 1,3-benzene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-benzene diisocyanate, 4,4'- are preferably used. Diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, hexamethylene Isocyanate.

The polyfunctional epoxy curing agent mainly refers to a compound having two or more epoxy groups and one or more tertiary nitrogen atoms, and examples thereof include N·N-glycidylaniline, N·N-glycidyltoluamide, and mN‧ N-glycidylaminophenyl glycidyl ether, pN‧N-glycidylaminophenyl glycidyl ether, triglycidyl isocyanurate, N‧N‧N'‧N'-tetraglycidyl Diaminodiphenylmethane, N‧N‧N'‧N'-tetraglycidyl-m-xylylenediamine, N‧N‧N'‧N'‧N"-pentacylidene di Ethyltriamine and the like.

(photopolymerization initiator)

The amount of the photopolymerization initiator to be added is 0.1 parts by mass to 20 parts by mass, preferably 1 part by mass to 10 parts by mass, per 100 parts by mass of the (meth) acrylate polymer. When the amount of the mixture is too small, the peeling property from the dicing tape after the light irradiation is lowered, and the pickup failure of the semiconductor wafer is likely to occur. On the other hand, when the amount of the mixture is too large, the photopolymerization initiator oozes out to the surface of the pressure-sensitive adhesive, which causes contamination.

As a photopolymerization initiator, benzoin, benzoin alkyl ether, acetophenone, anthracene, Thioxanthone, ketal, benzophenone or xanthone.

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

Examples of the acetophenones include benzoin alkyl ethers, acetophenone, 2,2-dimethoxy-2-acetophenone, and 2,2-diethoxy-2-acetophenone. 1,1-dichloroacetophenone and the like.

Examples of the hydrazine include 2-methylhydrazine, 2-ethylhydrazine, 2-tert-butylhydrazine, 1-chloroindole and the like.

Examples of the thioxanthone include 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, and the like. .

Examples of the ketal include acetophenone dimethyl ketal, benzyl ketal, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, bibenzyl, Bis-acetyl, β-chloropurine and the like.

In the photopolymerization initiator, one or two or more kinds of conventionally known photopolymerization accelerators may be used in combination as needed. As a photopolymerization accelerator, a benzoic acid type, a tertiary amine, etc. can be used. Examples of the tertiary amine include triethylamine, tetraethylpentamine, and dimethylaminoether.

(bonding resin)

The adhesion-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 a phenol of 0.1 to 50.

Examples of the terpene compound include myrcene, allo-ocimene, basilene, α-pinene, β-pinene, dipentene, limonene, α-phellandrene, α-terpinene, and γ-pine oil. Alkene, terpinolene, 1,8-eucalyptol, 1,4-carotin, α-terpineol, β-terpineol, γ-terpineol, terpene, tricycloolefin, terpene , for menthenes, terpenes, and the like. Among these compounds, α-pinene, β-pinene, limonene, myrcene, allo-ocimene, and α-terpinene are particularly preferably used in the present invention.

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

The ratio of the phenols of the terpene phenol resin is about 25 to 50% by mole, but is not limited thereto.

The hydroxyl value of the fully or partially hydrogenated terpene phenol resin is preferably from 50 to 250. When the hydroxyl value is less than 50, the reaction with the isocyanate curing agent is insufficient, and it oozes out to the surface of the binder, which causes contamination. If it is more than 250, the viscosity increases to produce a copolymer with (meth) acrylate. The mixing is uneven, and the pickup characteristics are unstable.

The hydrogenation method is not particularly limited, and examples thereof include a method in which a noble metal such as palladium, rhodium or ruthenium or a material such as activated carbon, activated alumina or diatomaceous earth is supported 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% by mole or more, and more preferably 70% by mole or more. When the amount is less than 30% by mole, the reaction of the photopolymerizable compound due to the irradiation of the active light rays is inhibited, and the adhesive strength is not sufficiently lowered, so that the pickup property is lowered.

The compounding ratio of the completely or partially hydrogenated terpene phenol resin is preferably 0.5 parts by mass to 100 parts by mass, more preferably 1.0 parts by mass to 50 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer. When the total or partial hydrogenated terpene phenol resin is 0.5 parts by mass or more, the adhesive force is not excessively lowered, and the retention of the semiconductor wafer at the time of dicing is maintained, and if it is 100 parts by mass or less, the occurrence of pickup failure 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 may be added to the pressure-sensitive adhesive composition.

The thickness of the pressure-sensitive adhesive layer is 3 to 7 μm, preferably 4 to 6 μm. If the pressure-sensitive adhesive layer is too thick, cracking easily occurs. Further, when the pressure-sensitive adhesive layer is too thin, the adhesive strength is too low, and wafer holding property at the time of cutting may be lowered to cause the wafer to scatter or peeling property may occur between the ring frame and the sheet.

(substrate film)

Examples of the material of the base film include an ionomer resin obtained by crosslinking a metal ion with a metal ion, polyethylene terephthalate, acetic acid-vinyl acetate copolymer, and the like. Ethylene-acrylic acid-acrylate film, ethylene-ethyl acrylate copolymer, polyethylene, polypropylene, A propylene-based copolymer, an ethylene-acrylic acid copolymer, an ethylene-(meth)acrylic acid copolymer, or an ethylene-(meth)acrylic acid-(meth)acrylate copolymer. The base film may be a mixture or a copolymer of these resins, or may be a laminate of films or sheets composed of these resins.

The material of the substrate film is preferably an ionomer resin. As the ionomer resin, if a copolymer having an ethylene unit, a methacrylic acid unit, and an alkyl (meth) acrylate unit is crosslinked by a metal ion such as Na ⁺ , K ⁺ or Zn ²⁺ . The resin is preferably used because the chip suppressing effect is remarkable.

The base film may be a single layer or a multilayer film or sheet composed of the above materials, or may be a laminate of a film made of a different material or the like. The thickness of the base film is 50 to 200 μm, preferably 70 to 150 μm.

It is preferred to subject the substrate film to an antistatic treatment. As the antistatic treatment, there are a treatment in which an antistatic agent is blended in a base film, a treatment in which an antistatic agent is applied on the surface of a 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 dimethylaminoethyl (meth) acrylate quaternary salt, diethylaminoethyl (meth) acrylate quaternary salt, and methyl (meth) acrylate. Ethylaminoethyl chloride quaternary salt, p-dimethylaminostyrene chlorinated quaternary salt, and p-diethylaminostyrene chlorinated quaternary salt. Among them, dimethylaminoethyl methacrylate chloride quaternary salt is preferred.

The method of using the slip agent and the antistatic agent is not particularly limited. For example, a binder may be applied to one surface of the substrate film, a slip agent and/or an antistatic agent may be applied to the back surface, and a slip agent and/or an antistatic agent may be applied. The film is mixed in the resin mixed in the base film.

The adhesive may be laminated on one surface of the base film, and the other surface 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 base film can be easily expanded in the expansion step after cutting.

(sliding agent)

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

The sliding agent is not particularly limited as long as it reduces the friction coefficient of the dicing tape and the expansion device, and examples thereof include an organic hydrazine compound such as an organic hydrazine resin or a (modified) eucalyptus oil, a fluororesin, a hexagonal boron nitride, and a carbon black. And molybdenum disulfide. These friction reducing agents can also be mixed with various components. In order to manufacture an electronic component in a clean room, it is preferable to use an organic hydrazine compound or a fluororesin. Among the organic ruthenium compounds, in particular, a copolymer having an organic oxime macromonomer unit has good compatibility with an antistatic layer, and can achieve a balance between antistatic property and expandability, and thus is preferably used.

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

(1) Attachment steps

First, in the attaching step, the dicing tape is attached to the semiconductor wafer or substrate and the ring frame. The semiconductor wafer may be a conventional wafer such as a germanium wafer and a gallium nitride wafer, a tantalum carbide wafer, or a sapphire wafer. The substrate may be a general-purpose substrate such as a package substrate, an LED package substrate, or a ceramic substrate obtained by sealing a wafer with a resin.

(2) Cutting step

In the dicing step, the semiconductor wafer or substrate is diced to form a semiconductor wafer or 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 irradiated from the side of the substrate film. As a light source of ultraviolet rays, a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, or a metal halide lamp can be used. Further, an electron beam may be used instead of the ultraviolet light, and as the electron beam source, α rays, β rays, and γ rays may be used.

By the light irradiation, the pressure-sensitive adhesive layer is three-dimensionally reticulated and solidified, and the adhesive strength of the pressure-sensitive adhesive layer is lowered. At this time, as described above, the dicing tape according to the present invention does not excessively adhere to the semiconductor wafer or the substrate even when heated, so that a sufficiently low adhesive force can be obtained by irradiation with ultraviolet rays or the like.

(4) Extension ‧ Pickup steps

In the expansion ‧ picking step, in order to enlarge the interval between the semiconductor wafer or the semiconductor member, the dicing tape is stretched, and the wafer or the member is pushed up by a pin or the like. Thereafter, the vacuum chuck or the pneumatic chuck or the like attracts the wafer or the member to be peeled off from the adhesive layer of the dicing tape to be picked up. this In the case where the dicing tape according to the present invention is sufficiently irradiated by irradiation with ultraviolet rays or the like, the adhesion between the wafer or the member and the pressure-sensitive adhesive layer is facilitated, and good pick-up property is obtained, and no detachment occurs. Bad phenomenon such as residual glue.

<Manufacture of dicing tape>

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

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

[Examples]

The adhesive composition and the dicing tape of Example ‧ Comparative Example were produced according to the following formula. The main components and the results of the respective experimental examples are shown in Tables 1 to 3.

The numerical values of the compositions in Tables 1 to 3 represent parts by mass. The numerical value of the photopolymerizable compound, the curing agent, and the photopolymerization initiator indicates the 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.

Incidentally, 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 (made by Tosoh Corporation)

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

Flow rate: 0.5ml/min

Detector: RI-8020

Concentration: 0.2wt/Vol%

Injection volume: 20μL

Column temperature: 40 ° C

System temperature: 40 ° C

Solvent: THF

Standard curve: It was produced using standard polystyrene (manufactured by PL Corporation), and the weight average molecular weight (Mw) was expressed in terms of polystyrene.

<Substrate film>

‧ Resin film A: An ionomer resin film having a thickness of 80 μm was 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. (commercial product).

<Photopolymerizable compound>

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

‧ Photopolymerizable compound B: a urethane acrylate oligomer (synthetic product) having a weight average molecular weight of 4,200 and an unsaturated double bond functional group of 10 synthesized by the same method as the photopolymerizable compound A

‧ Photopolymerizable compound C: a urethane acrylate oligomer (synthetic product) having a weight average molecular weight of 2,100 and an unsaturated double bond functional group of 10 synthesized by the same method as the photopolymerizable compound A

‧ Photopolymerizable compound D: a urethane acrylate oligomer (synthetic product) having a weight average molecular weight of 10,300 and an unsaturated double bond functional group of 10 synthesized by the same method as the photopolymerizable compound A

‧ Photopolymerizable compound E: a compound obtained by reacting a trimer isocyanate of isophorone diisocyanate with a hydroxyl group-containing acrylate having dipentaerythritol pentaacrylate as a main component, and a weight average molecular weight A urethane acrylate oligomer (synthesis product) having 4,900 and an unsaturated double bond functional group number of 15.

In addition, the photopolymerizable compound is prepared by a known method described in JP-A-61-42529.

<curing agent>

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

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

‧ Curing agent C: N, N, N', N'-tetraglycidyl m-xylylene diamine (commercially available)

<Photopolymerization initiator>

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

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

(1) Adhesion

According to JIS Z 0237; 2009, a tensile tester (RTG-1210, manufactured by A&D Co., Ltd.) was used, and the dicing tape attached to the enamel wafer was measured by a 180° peeling method and the dicing tape after 20 minutes passed at 23 ° C, relative humidity. Adhesion at 50%. The stretching speed was 300 mm/min, and the size of the dicing tape was 250 mm × 20 mm. It should be noted that the mirror surface of the tantalum wafer is mirror surface manufactured according to JIS H 0614.

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

The resulting dicing tape was attached to a ruthenium wafer and a ring frame having a diameter of 8 inches × 0.15 mm formed with a dummy circuit pattern. After bonding for 20 minutes, ultraviolet rays of 150 mJ/cm ² were irradiated with a high-pressure mercury lamp, and thereafter, each step was cut and picked up.

The conditions of the cutting step are as follows.

Cutting device: DDAC341 made by DISCO

Cutting blade: NBC-ZH205O-27HEEE made by DISCO

The shape of the cutting blade: outer diameter 55.56mm, blade width 35μm, inner diameter 19.05mm

Cutting blade speed: 40,000 rpm

Cutting blade feed speed: 100mm / sec

Cutting size: 1.0mm square

Cut in the cutting tape: 30μm

Cutting water temperature: 25 ° C

Cutting water volume: 1.0 L / min

The conditions for the pickup step are as follows.

Pickup device: CAP-300II manufactured by Canon Machinery Co., Ltd.

Expansion amount: 8mm

Pin shape: 70μmR

Number of pins: 1

Pin push up height: 0.3mm

In the cutting step and the picking step, the following evaluations were made.

(2-1) Wafer retention

Wafer retention was evaluated according to the following criteria based on the residual ratio of the semiconductor wafer held by the semiconductor wafer on the dicing tape after the dicing step.

◎ (Excellent): The wafer scatters less than 5%

○ (good): the wafer is scattered more than 5% and less than 10%

× (not available): The wafer is scattered more than 10%

(2-2) Pickup

The pickup property was evaluated according to the following criteria based on the ratio of the semiconductor wafer that can be picked up in the pickup step.

◎ (Excellent): The chip picking success rate is over 95%

○ (good): The pick-up success rate of the wafer is 80% or more and less than 95%.

× (not available): wafer pick-up success rate is less than 80%

(2-3) Chipping

For the cracking, 50 picked wafers were randomly selected, and four sides of the back surface of the wafer were observed with a microscope of 500 times, and the maximum defect in the center direction was evaluated according to the following criteria.

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

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

× (not available): the defect size is 50 μm or more

(3) Pollution

The dicing tape was attached to the mirror surface of the enamel wafer, and after 20 minutes, the ultraviolet ray of 150 mJ/cm ² was irradiated with a high pressure mercury lamp, and the dicing tape was peeled off. The number of particles of 0.28 μm or more remaining on the mirror surface (attach surface) of the tantalum wafer was measured by a particle counter.

◎ (Excellent): The particles are less than 500

○ (good): The particles are 501 or more and less than 2000.

× (not available): The number of particles is 2,000 or more.

(4) The wafer is loose

The looseness of the wafer was evaluated according to 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.

◎ (Excellent): The wafer is looser than 1%

○ (good): The wafer is loosened to 1% or more and less than 3%.

× (not available): The wafer is loosened to 3% or more

(examine)

As shown in the examples and comparative examples of Tables 1 to 3, in all of the examples in which the pressure-sensitive adhesive layer having a thickness of 3 to 7 μm was formed using a pressure-sensitive adhesive having a specific composition, it was judged to be ○ or ◎. On the other hand, in all of the comparative examples in which the composition of the pressure-sensitive adhesive or the thickness of the pressure-sensitive adhesive layer was specified, the overall judgment was ×. From these results, it was confirmed that when the dicing tape of the present invention is used, cracking, wafer scattering, and residual glue can be effectively suppressed, and pick-up property can be improved.

Further detailed analysis is performed as follows.

In Comparative Example 1, since the methyl (meth) acrylate unit was too small, the contamination property was poor.

In Comparative Example 2, since the methyl (meth) acrylate unit was too large, the wafer retainability 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 were too many monomer units having a carboxyl group, pick-up property and contamination property were inferior.

In Comparative Example 5, since the number of monomer units having a hydroxyl group was too small, the contamination property was poor.

In Comparative Example 6, since the number of monomer units having a hydroxyl group was too large, the wafer was easily loosened.

In Comparative Example 7, since the photopolymerizable compound was too small, the wafer retainability and the pick-up property were inferior.

In Comparative Example 8, since the photopolymerizable compound was too large, the contamination property 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, cracking easily occurred.

In Comparative Example 10, since the weight average molecular weight of the photopolymerizable compound was too large, 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 amount of the curing agent was too large, the wafer retention property and the contamination property were poor, and the wafer was easily loosened.

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

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

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

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

Claims (4)

A dicing tape formed by laminating a pressure-sensitive adhesive layer composed of an adhesive composition on a substrate film, wherein the pressure-sensitive adhesive composition contains 100 parts by mass of a (meth) acrylate copolymer 5 to 250 parts by mass of the photopolymerizable compound, 0.1 to 20 parts by mass of the curing agent, and 0.1 to 20 parts by mass of the photopolymerization initiator, and the (meth) acrylate copolymer contains the methyl (meth) acrylate unit 35 ~85 mass%, 10 to 60% by mass of 2-ethylmethyl (meth)acrylate unit, 0.5 to 10% by mass of a monomer unit having a carboxyl group, and 0.05 to 5% by mass of a monomer unit having a hydroxyl group. 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 pressure-sensitive adhesive layer has a thickness of 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 the dicing tape has an adhesive force against a mirror surface of the enamel wafer measured according to JIS Z 0237 of 5.0 N/20 mm or more. A method of manufacturing an electronic component, comprising the steps of: (a) attaching a step of attaching a dicing tape to a semiconductor wafer or a substrate and a ring frame; and (b) cutting a step of cutting the semiconductor wafer or a substrate to form a semiconductor wafer or a semiconductor component; (c) a light irradiation step of irradiating the dicing tape with active light; (d) an expanding step of expanding an interval between the semiconductor wafer or the semiconductor component The dicing tape is stretched; and (e) a picking step of picking up a semiconductor wafer or a semiconductor component from the dicing tape, wherein the dicing tape is the dicing tape of any one of claims 1 to 3.