CN107112221B

CN107112221B - Cutting adhesive tape

Info

Publication number: CN107112221B
Application number: CN201680004665.7A
Authority: CN
Inventors: 津久井友也
Original assignee: Denka Co Ltd
Current assignee: Denka Co Ltd
Priority date: 2015-01-09
Filing date: 2016-01-05
Publication date: 2020-12-22
Anticipated expiration: 2036-01-05
Also published as: JP6604972B2; KR102474023B1; JPWO2016111283A1; CN107112221A; TW201636408A; TWI678409B; WO2016111283A1; KR20170106982A

Abstract

The invention provides a dicing tape which can suppress chip scattering and chipping in a dicing process even in a small and thin electronic component, can be picked up easily, and is less likely to cause adhesive residue. According to the present invention, there is provided a dicing tape comprising a base film and a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition laminated on the base film, characterized in that the adhesive composition comprises 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 to 85 mass% of methyl (meth) acrylate units, 10 to 60 mass% of 2-ethylhexyl (meth) acrylate units, 0.5 to 10 mass% of monomer units having a carboxyl group, and 0.05 to 5 mass% of monomer units having a hydroxyl group を 0.05, the photopolymerizable compound has a weight average molecular weight of 4000 to 8000, and the number of unsaturated double bond functional groups is 10 to 15, and the thickness of the adhesive layer is 3 to 7 μm.

Description

Cutting adhesive tape

[ technical field ] A method for producing a semiconductor device

The present invention relates to a dicing tape used in a process for manufacturing an electronic component.

[ background of the invention ]

After the dicing tape is attached to the semiconductor wafer or substrate, the semiconductor wafer or substrate undergoes various steps such as dividing (dicing) into element pieces, extending (spreading) the dicing tape, and peeling (picking up) the element pieces from the dicing tape. The dicing tape used in these steps is desired to have sufficient adhesive force to the element pieces (chips) formed in the dicing step and to have adhesive force reduced to such an extent that no adhesive residue is generated in the pick-up step.

As the dicing tape, there are the following dicing tapes: a pressure-sensitive adhesive layer that causes a polymerization curing reaction by ultraviolet rays or the like is coated on a base film that transmits active light rays such as ultraviolet rays and/or electron beams. The cutting adhesive tape adopts the following method: after the dicing step, the adhesive layer is irradiated with ultraviolet rays or the like to polymerize and cure the adhesive layer, thereby reducing the adhesive strength, and then the divided chips are picked up.

As such dicing tapes, patent documents 1 and 2 disclose dicing tapes in which a pressure-sensitive adhesive containing a compound (polyfunctional oligomer) having a photopolymerizable unsaturated double bond in the molecule, which is capable of forming a three-dimensional network by actinic rays, is applied to the surface of a substrate film.

[ Prior art documents ]

[ patent document ]

[ patent document 1 ] Japanese patent laid-open No. 2006 and 049509

[ patent document 2 ] Japanese patent laid-open No. 2007-246633

[ summary of the invention ]

[ problem to be solved by the invention ]

In recent years, with the miniaturization and thinning of electronic components, chip scattering and chipping (chip chipping) are likely to occur in the dicing step of a semiconductor wafer or substrate, and this may cause a reduction in yield.

Accordingly, a main object of the present invention is to provide a dicing tape which can suppress chip scattering and chipping in a dicing step even in a small and thin electronic component, is easy to pick up, and is less likely to cause adhesive residue.

[ means for solving problems ]

According to the present invention, there is provided a dicing tape comprising a base film and a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition laminated on the base film, characterized in that the adhesive composition comprises 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 to 85 mass% of methyl (meth) acrylate units, 10 to 60 mass% of 2-ethylhexyl (meth) acrylate units, 0.5 to 10 mass% of monomer units having a carboxyl group, and 0.05 to 5 mass% of monomer units having a hydroxyl group, the photopolymerizable compound is a urethane acrylate oligomer having a weight average molecular weight of 4000 to 8000 and a number of unsaturated double bond functional groups of 10 to 15, and the adhesive layer has a thickness of 3 to 7 μm.

Generally, if the thickness of the pressure-sensitive adhesive layer is reduced, chipping is less likely to occur, but the adhesive force is reduced, and chip scattering is likely to occur. Further, when the composition of the adhesive is adjusted to suppress the occurrence of chip scattering, the following problems are likely to occur: chipping or deterioration in pickup properties or adhesive residue is likely to occur. Therefore, it has been difficult to effectively suppress chipping, chip scattering, and adhesive residue and to improve the pickup property.

The present inventors have conducted intensive studies to obtain a dicing tape excellent in these respects, and as a result, have found that when a pressure-sensitive adhesive layer having a thickness of 3 to 7 μm is formed using a pressure-sensitive adhesive having a specific composition, chipping, chip scattering, and adhesive residue can be effectively suppressed, and pickup properties are improved, thereby completing the present invention.

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

Preferably, the dicing tape is characterized in that the adhesive force to the mirror surface of the silicon wafer measured according to JIS Z0237 is 5.0N/20mm or more.

According to another aspect of the present invention, there is provided a method for manufacturing an electronic component, including the steps of: (a) a bonding step of bonding a dicing tape to the semiconductor wafer or substrate and the ring frame; (b) a dicing step of dicing the semiconductor wafer or substrate to form semiconductor chips or semiconductor components; (c) irradiating the dicing tape with active light in a light irradiation step; (d) a spreading step of stretching the dicing tape to spread the interval between the semiconductor chips or the semiconductor components; and (e) a picking-up step of picking up a semiconductor chip or a semiconductor component from the dicing tape, the dicing tape being the dicing tape described above.

[ Effect of the invention ]

According to the present invention, there can be provided a dicing tape: even a small and thin electronic component, the chip can be prevented from scattering and chipping in the dicing step, and the chip can be easily picked up (pick up) and is less likely to cause adhesive residue.

[ detailed description ] embodiments

Preferred embodiments for carrying out the present invention will be described below. The embodiments described below are merely examples of typical embodiments of the present invention, and the scope of the present invention is not to be construed as being too narrow.

< adhesive composition >

The adhesive composition used 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, 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) acrylate copolymer contains: 35 to 85 mass% (preferably 45 to 75 mass%, more preferably 50 to 70 mass%, further preferably 55 to 65 mass%) of methyl (meth) acrylate units, 10 to 60 mass% (preferably 20 to 50 mass%, more preferably 25 to 45 mass%, further preferably 30 to 40 mass%) of 2-ethylhexyl (meth) acrylate units, 0.5 to 10 mass% (preferably 2 to 7 mass%, further preferably 3 to 6 mass%, further preferably 4 to 5 mass%) of monomer units having a carboxyl group, 0.05 to 5 mass% (preferably 0.1 to 3 mass%, further preferably 0.2 to 2 mass%, further preferably 0.3 to 1 mass%, further preferably 0.4 to 0.7 mass%) of monomer units having a hydroxyl group. By forming the (meth) acrylate copolymer with such monomer units, a dicing tape having sufficiently high adhesive strength can be obtained even when the thickness of the adhesive layer is small, i.e., 3 to 7 μm. The adhesive force of the dicing tape is preferably 5.0N/20mm or more to the mirror surface of the silicon wafer as measured according to JIS Z0237.

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

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

(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, based on 100 parts by mass of the (meth) acrylate copolymer. When the amount of the photopolymerizable compound to be mixed is reduced, the peeling property of the dicing tape after irradiation with active light such as ultraviolet rays is reduced, and thus a pickup failure of the semiconductor chip is likely to occur. On the other hand, if the amount of the photopolymerizable compound to be mixed is increased, the adhesive force is excessively reduced in the light irradiation step, and chip looseness occurs in the pickup step, which causes a reduction in productivity.

The photopolymerizable compound that can be used in the present invention is a urethane acrylate oligomer having a weight average molecular weight of 4000 to 8000 and a functional group number of unsaturated double bonds of 10 to 15. When the weight average molecular weight is small, the binder is soft at the side, so that chipping is likely to occur, and when the weight average molecular weight is large, adhesion to an adherend is reduced, and scattering of chips is likely to occur. If the number of unsaturated double bond functional groups is small, the curability of the adhesive after irradiation with ultraviolet rays or the like is reduced, and pickup failure is likely to occur, whereas if 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, and chip loosening occurs. Further, when a urethane acrylate oligomer is used, there is an advantage that adhesive residue is not easily generated at the time of pickup because of excellent adhesion to a base film and flexibility.

The urethane acrylate oligomer can be obtained by reacting a hydroxyl group-containing (meth) acrylate with a polyester-type or polyether-type isocyanate-terminated urethane prepolymer obtained by reacting a polyol compound with a polyol compound.

Examples of the polyol compound include ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, pentanediol, glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, and the like. Examples of the polyisocyanate compound include 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1, 3-xylylene diisocyanate, 1, 4-xylylene diisocyanate, diphenylmethane 4, 4-diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. 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 monohydroxypentaacrylate, and the like.

(curing agent)

The amount of the curing agent to be mixed is 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer. When the amount of the curing agent to be mixed is reduced, the generation of residual gum is likely to occur. On the other hand, if the amount of the curing agent to be mixed is increased, insufficient adhesion and chip loosening occur, which cause 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 curing agents, the carboxyl group-containing functional group-containing monomer can be selectively reacted and reduced, and therefore the amount of the carboxyl group-containing functional group-containing monomer 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-phenylene diisocyanate, 4 '-diphenyldiisocyanate, 1, 4-phenylene diisocyanate, 4' -diphenylmethane diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 4 '-toluidine diisocyanate, 2,4, 6-triisocyanatotoluene, 1,3, 5-triisocyanatobenzene, dianisidine diisocyanate, 4' -diphenylether diisocyanate, 4 '-triphenylmethane triisocyanate, ω' -diisocyanate-1, 3-dimethylbenzene, ω '-diisocyanate-1, 4-diethylbenzene, 1, 4-tetramethylxylylene diisocyanate, 4' -diphenylene diisocyanate, and the like, 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, pentamethylene diisocyanate, 1, 2-propylene diisocyanate, 2, 3-butylene diisocyanate, 1, 3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4, 4-trimethylhexamethylene diisocyanate.

The alicyclic polyisocyanate is not particularly limited, and examples thereof include 3-isocyanatomethyl-3, 5, 5-trimethylcyclohexyl isocyanate, 1, 3-cyclopentanediisocyanate, 1, 3-cyclohexanediisocyanate, 1, 4-cyclohexanediisocyanate, methyl-2, 6-cyclohexanediisocyanate, 4' -methylenebis (cyclohexylisocyanate), 1, 4-bis (isocyanatomethyl) cyclohexane and 1, 4-bis (isocyanatomethyl) cyclohexane.

Among the polyisocyanates, 1, 3-phenylene diisocyanate, 4' -diphenyl diisocyanate, 1, 4-phenylene diisocyanate, 4' -diphenylmethane diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 4' -toluidine diisocyanate and hexamethylene diisocyanate are preferably used.

The polyfunctional epoxy hardener is a compound having mainly 2 or more epoxy groups and 1 or more tertiary nitrogen atoms, and examples thereof include N.N-glycidylaniline, N.N-glycidyltoluidine, m-N.N-glycidylaminophenylglycidyl ether, p-N.N-glycidylaminophenylglycidyl ether, triglycidyl isocyanurate, N.N.N '. N' -tetraglycidyldiaminodiphenylmethane, N.N.N '. N' -tetraglycidyl-m-xylylenediamine, and N.N.N '. N' -pentaglycidyldiethylenetriamine.

(photopolymerization initiator)

The amount of the photopolymerization initiator to be mixed is 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, per 100 parts by mass of the (meth) acrylate polymer. If the amount of the compound is too small, the releasability from the dicing tape after light irradiation is reduced, and a pickup failure of the semiconductor chip is likely to occur. On the other hand, if the amount is too large, the photopolymerization initiator bleeds out to the surface of the pressure-sensitive adhesive, which causes contamination.

As the photopolymerization initiator, benzoin alkyl ethers, acetophenones, anthraquinones, thioxanthones, ketals, benzophenones, xanthones, or the like is used.

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

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

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

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

As ketals, there are, for example, acetophenone dimethyl ketal, benzyl diketal, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, diacetyl, β -chloroanthraquinone and the like.

The photopolymerization initiator may be used in combination with 1 or 2 or more conventionally known photopolymerization accelerators, as required. As the photopolymerization accelerator, benzoic acids, tertiary amines and the like can be used. Examples of the tertiary amine include triethylamine, tetraethylpentamine, and dimethylamino ether.

(adhesion imparting resin)

An 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 mole of a terpene compound with 0.1 to 50 moles of a phenol.

Examples of the terpene compound include myrcene, alloocimene, ocimene, α -pinene, β -pinene, dipentene, limonene, α -phellandrene, α -terpinene, γ -terpinene, isoterpinene, 1, 8-cineole, 1, 4-cineole, α -terpineol, β -terpineol, γ -terpineol, camphene, tricyclene, sabinene, p-menthadiene, carene and the like. Of these compounds, α -pinene, β -pinene, limonene, myrcene, alloocimene and α -terpinene are particularly preferably used in the present invention.

Examples of the phenol include phenol, cresol, xylenol, catechol, resorcinol, hydroquinone, and bisphenol a, but the phenol is not limited thereto.

The proportion of phenols in the terpene-phenol resin is 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. If the hydroxyl value is less than 50, the reaction with the isocyanate-based curing agent is insufficient, and the resulting product bleeds out to the surface of the pressure-sensitive adhesive, which may cause contamination, whereas if the hydroxyl value is more than 250, the viscosity increases, resulting in uneven mixing with the (meth) acrylate copolymer or the like, and the pickup characteristics are unstable.

The hydrogenation method is not particularly limited, and examples thereof include the following methods: the hydrogenation rate can be measured by a method using a noble metal such as palladium, ruthenium, or rhodium or a substance obtained by supporting the noble metal on a carrier such as activated carbon, activated alumina, or diatomaceous earth as a catalyst, for example, by bromine number measurement or iodine number measurement.

The hydrogenation ratio of the completely or partially hydrogenated terpene-phenol resin is preferably 30 mol% or more, and more preferably 70 mol% or more. If the amount is less than 30 mol%, the adhesive force may not be sufficiently reduced due to reaction inhibition of the photopolymerizable compound by irradiation with active light, and the pickup property may be reduced.

The blending ratio of the completely or partially hydrogenated terpene-phenol resin is preferably 0.5 to 100 parts by mass, more preferably 1.0 to 50 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer. When the terpene-phenol resin is completely or partially hydrogenated at 0.5 parts by mass or more, the adhesive force is not excessively low, the holding property of the semiconductor chip during dicing is maintained, and when it is 100 parts by mass or less, the occurrence of pickup failure can be suppressed.

(additives, etc.)

Various additives such as a softening agent, an aging inhibitor, 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 adhesive layer is 3 to 7 μm, preferably 4 to 6 μm. If the adhesive layer is too thick, chipping is likely to occur. If the pressure-sensitive adhesive layer is too thin, the adhesive force becomes too low, and chip holding performance during dicing may be reduced to cause chip scattering or peeling between the ring frame and the sheet.

(substrate 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 copolymers, ethylene-acrylic acid-acrylic ester films, ethylene-ethyl acrylate copolymers, polyethylene, polypropylene, propylene-based copolymers, ethylene-acrylic acid copolymers, and ethylene- (meth) acrylic acid copolymers or ethylene- (meth) acrylic acid- (meth) acrylic ester copolymers. The substrate film may be a mixture or copolymer of these resins, or may be a laminate of films or sheets made of these resins.

The material of the substrate film is preferably an ionomer resin. As the ionomer resin, a copolymer having an ethylene unit, a methacrylic acid unit and an alkyl (meth) acrylate unit, Na or the like is used⁺、K⁺、Zn²⁺Ionomer resins crosslinked with a metal ion are preferably used because they have a significant effect of suppressing cutting chips.

The substrate 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 made of different materials or the like. The thickness of the base film is 50 to 200 μm, preferably 70 to 150 μm.

The substrate film is preferably subjected to antistatic treatment. Examples of the antistatic treatment include a treatment in which an antistatic agent is incorporated into a base film, a treatment in which an antistatic agent is applied to the surface of a base film, and a treatment by 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 chloride salt, diethylaminoethyl (meth) acrylate quaternary chloride salt, methylethylaminoethyl (meth) acrylate quaternary chloride salt, p-dimethylaminostyrene quaternary chloride salt, and p-diethylaminostyrene quaternary chloride salt. Among them, dimethylaminoethyl methacrylate quaternary chloride is preferable.

The method of using the slip agent and the antistatic agent is not particularly limited, and for example, a pressure-sensitive adhesive may be applied to one surface of the base film, and the slip agent and/or the antistatic agent may be applied to the back surface thereof, or the slip agent and/or the antistatic agent may be mixed into the resin of the base film and formed into a sheet.

The adhesive can be laminated on one surface of the base film, and the other surface can be an embossed surface having an average surface roughness (Ra) of 0.3 to 1.5 [ mu ] m. By providing the embossed surface on the machine side of the expanding device, the base material film can be easily expanded in the expanding process after cutting.

(slip agent)

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

The sliding agent is not particularly limited as long as it lowers the coefficient of friction between the dicing tape and the spreading device, and examples thereof include silicone compounds such as silicone resins and (modified) silicone oils, fluorine resins, hexagonal boron nitride, carbon black, and molybdenum disulfide. These friction reducers may also be mixed with a plurality of ingredients. For manufacturing electronic parts in a clean room, it is preferable to use an organic silicon compound or a fluorine resin. Among the organosilicon compounds, a copolymer having an organosilicon macromonomer unit is preferably used because it has good compatibility with an antistatic layer and can balance antistatic properties and expansibility.

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

(1) Sticking process

First, in the attaching process, a 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 silicon wafer, a gallium nitride wafer, a silicon carbide wafer, or a sapphire wafer. The substrate may be a general-purpose substrate such as a package substrate in which a chip is sealed with a resin, an LED package substrate, or a ceramic substrate.

(2) Cutting procedure

In the dicing step, the semiconductor wafer or substrate is diced to form semiconductor chips or semiconductor parts.

(3) Light irradiation step

In the light irradiation step, the dicing tape is irradiated with active light such as ultraviolet light or electron beam. The active light is preferably irradiated from the substrate film side. As the light source of the 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. Instead of ultraviolet rays, electron beams may be used, and α rays, β rays, and γ rays may be used as the electron beam light source.

The pressure-sensitive adhesive layer is three-dimensionally reticulated and cured by light irradiation, and the adhesive force of the pressure-sensitive adhesive layer is reduced. In this case, 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, and therefore, sufficiently low adhesion can be obtained by irradiation with ultraviolet rays or the like.

(4) Expanding and picking up process

In the expanding and picking-up step, in order to enlarge the interval between the semiconductor chips or semiconductor components, the dicing tape is stretched and the chips or components are pushed up by pins or the like. Thereafter, the chip or the component is sucked by a vacuum chuck, a pneumatic chuck, or the like, and peeled off from the adhesive layer of the dicing tape to be picked up. In this case, since the dicing tape according to the present invention can sufficiently reduce the adhesive strength by irradiation with ultraviolet rays or the like, the chip or the member can be easily peeled from the pressure-sensitive adhesive layer, and a good pickup property can be obtained without causing defects such as adhesive residue.

< production of dicing tape >

As a method for forming an adhesive layer on a base film to obtain a dicing tape, for example, the following methods are available: a method of directly coating an adhesive on a substrate film using a coater such as a gravure coater, a comma coater, a bar coater, a knife coater, or a roll coater; or a method in which the adhesive is applied to a release film, dried, and then bonded to a base film. The adhesive may also be printed on the substrate film by using a plate printing, gravure printing, offset printing, flexo printing, offset printing, screen printing or the like.

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

[ examples ] A method for producing a compound

Adhesive compositions and dicing tapes according to examples and comparative examples were produced according to the following formulations. 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 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 material film, photopolymerizable compound, curing agent, and photopolymerization initiator are as follows.

The weight average molecular weight is a value measured by Gel Permeation Chromatography (GPC) as a weight average molecular weight in terms of polystyrene. Specifically, the following is described.

GPC-8020 SEC System (manufactured by Tosoh corporation)

TSK Guard HZ-L + HZM-N6.0 x 150mm x 3

Flow rate of 0.5ml/min

Detector RI-8020

Concentration 0.2 wt/Vol%

The injection amount is 20 muL

The constant temperature is 40 DEG C

The system temperature is 40 DEG C

Solvent THF

A calibration curve was prepared using standard polystyrene (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, mainly containing Zn salt of ethylene-methacrylic acid-2-methylpropyl acrylate copolymer. MFR 2.8g/10min (JIS K7210, 210 ℃ C.), Mitsui DuPont Polychemicals K.K. (commercially available product).

< photopolymerizable Compound >

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

Photopolymerizable compound B urethane acrylate oligomer (synthetic product) having a weight average molecular weight of 4200 and the number of unsaturated double bond functional groups of 10, which was synthesized by the same method as for photopolymerizable compound A

Photopolymerizable Compound C A urethane acrylate oligomer (synthetic product) having a weight average molecular weight of 2100 and a number of unsaturated double bond functional groups of 10, which was synthesized by the same method as for the photopolymerizable Compound A

Photopolymerizable Compound D A-urethane acrylate oligomer (synthetic product) having a weight average molecular weight of 10300 and 10 unsaturated double bond functional groups and synthesized by the same production method as for photopolymerizable Compound A

A photopolymerizable compound E which was obtained by reacting an isocyanate which is a trimer of isophorone diisocyanate with a hydroxyl-containing acrylate which is a main component of dipentaerythritol pentaacrylate, and a urethane acrylate oligomer (synthetic product) having a weight average molecular weight of 4900 and a functional group number of unsaturated double bonds of 15.

The photopolymerizable compound is produced by a known method described in, for example, Japanese patent application laid-open No. 61-42529.

< curing agent >

Curing agent A trimethylolpropane adduct of 2, 4-tolylene diisocyanate (commercially available)

Curing agent B trimethylolpropane adduct of hexamethylene diisocyanate (commercially available product)

Curing agent C N, N, N ', N' -tetraglycidyl m-xylylenediamine (commercially available)

< photopolymerization initiator >

Photopolymerization initiator A1-hydroxycyclohexyl phenyl ketone (commercially available)

Photopolymerization initiator B benzyl dimethyl ketal (commercially available)

[ TABLE 1 ]

[ TABLE 2 ]

[ TABLE 3 ]

(1) Adhesive force

According to JIS Z0237; 2009, the adhesive strength of the dicing tape, which was attached to the mirror surface of the silicon wafer and was peeled off at 23 ℃ and 50% of relative humidity for 20 minutes, was measured by a 180 ° peel method using a tensile tester (RTG-1210, manufactured by a & D company). The drawing speed was 300mm/min, and the size of the dicing tape was 250 mm. times.20 mm. The mirror surface of the silicon wafer was made according to JIS H0614.

(2) Evaluation of chip holding Property, pickup Property and chipping

The dicing tape obtained was attached to a silicon wafer having a diameter of 8 inches × a thickness of 0.15mm, on which a dummy circuit pattern was formed, and an annular frame. After 20 minutes of bonding, the substrates were irradiated with 150mJ/cm by a high-pressure mercury lamp²Then, the cutting and picking steps are performed.

The conditions of the cutting step are as follows.

Cutting device DAD341 manufactured by DISCO

Cutting blade NBC-ZH 205O-27 HEEE manufactured by DISCO

The cutting blade has an outer diameter of 55.56mm, a blade width of 35 μm, and an inner diameter of 19.05mm

Cutting blade rotating speed of 40000rpm

Cutting blade feed speed 100 mm/sec

1.0mm square of cutting size

30 μm of cut in the dicing tape

The temperature of cutting water is 25 DEG C

Cutting water amount 1.0 liter/min

The conditions of the pickup process are as follows.

Pickup device CAP-300 II manufactured by Canon Machinery corporation

Expansion of 8mm

Pin shape of 70 μmR

Number of pins 1

The push-up height of the pin is 0.3mm

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

(2-1) chip Retention

The chip holding property was evaluated according to the following criteria, based on the residual ratio of the semiconductor chips held by the dicing tape after the dicing step.

Excellent that the chip flying is less than 5%

Good chip fly-off of 5% or more and less than 10%

(not required) chip fly-off 10% or more

(2-2) pickup Property

The pick-up property was evaluated according to the following criteria, based on the proportion of semiconductor chips that could be picked up in the pick-up process.

Excellent (excellent) chip pick-up success rate is above 95%

Good, the chip pick-up success rate is 80% or more and less than 95%

X (not): chip pick-up success rate is less than 80%

(2-3) bursting (Chipping)

For chipping, 50 picked-up chips were randomly selected, and 4 sides of the back surface of the chip were observed with a microscope at 500 magnifications, and the size of the maximum defect in the center direction was evaluated according to the following criteria.

Excellent defect size less than 25 μm

Good defect size of 25 μm or more and less than 50 μm

(not less) defect size of 50 μm or more

(3) Polluting property

Attaching the dicing tape to the mirror surface of the silicon wafer, irradiating with a high-pressure mercury lamp at 150mJ/cm after 20 minutes²After the UV light, the dicing tape was peeled off. The number of particles having a particle diameter of 0.28 μm or more remaining on the mirror surface (adhesion surface) of the silicon wafer was measured by a particle counter.

Excellent that the number of the particles is 500 or less

Good-particles are 501 or more and less than 2000.

(not): 2000 or more particles.

(4) Chip loosening

The chip looseness was evaluated based on the following criteria, based on the proportion of the semiconductor chips adjacent to the semiconductor chip to be picked up in the picking-up process, which were loosened by the impact of the pin lifting.

Excellent performance that the chip looseness is less than 1 percent

Good, chip loosening was 1% or more but less than 3%

(not required) chip loosening of 3% or more

(examination)

As shown in the examples and comparative examples in tables 1 to 3, all of the examples in which the adhesive layer having a thickness of 3 to 7 μm was formed using the adhesive having a specific composition were judged as "good" or "excellent" in general. On the other hand, the composition of the pressure-sensitive adhesive or the thickness of the pressure-sensitive adhesive layer was judged to be x in all comparative examples except for the predetermined one. From these results, it was confirmed that: the dicing tape of the present invention can effectively suppress chipping, chip scattering, and adhesive residue, and can improve the pick-up property.

Further detailed analysis was performed as follows.

In comparative example 1, the number of methyl (meth) acrylate units was too small, and therefore the staining property was poor.

In comparative example 2, since the amount of methyl (meth) acrylate units was too large, the chip holding property was poor and the chip was liable to loosen.

In comparative example 3, since the monomer unit having a carboxyl group was too small, the chip retentivity was poor.

In comparative example 4, since the number of monomer units having a carboxyl group was too large, the picking-up property and the staining property were poor.

In comparative example 5, the contamination property was poor because the number of the monomer units having a hydroxyl group was too small.

In comparative example 6, since the monomer unit having a hydroxyl group was excessive, the chip was easily loosened.

In comparative example 7, the photopolymerizable compound was too small, and thus the chip holding property and the pickup property were poor.

In comparative example 8, since the photopolymerizable compound was too much, the staining property was poor and the chip was liable to loosen.

In comparative example 9, since the weight average molecular weight of the photopolymerizable compound was too small, chipping was likely to occur.

In comparative example 10, the photopolymerizable compound had too large a weight average molecular weight, and thus the chip retentivity was poor.

In comparative example 11, the curing agent was too small, and therefore, the staining property was poor.

In comparative example 12, since the curing agent was excessive, the chip holding property and staining property were poor, and the chip was liable to loosen.

In comparative example 13, the amount of the photopolymerization initiator was too small, and the pickup property was poor.

In comparative example 14, since the photopolymerization initiator was too much, the staining property was poor and the chip was liable to be loosened.

In comparative example 15, since the adhesive layer was too thin, the chip holding property was poor and the chip was easily loosened.

In comparative example 16, since the adhesive layer was too thick, chipping was likely to occur, and the pickup was poor.

Claims

1. A dicing tape comprising a base film and a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition laminated on the base film,

the adhesive composition comprises 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 to 85 mass% of a methyl (meth) acrylate unit, 10 to 60 mass% of a 2-ethylhexyl (meth) acrylate unit, 0.5 to 10 mass% of a monomer unit having a carboxyl group, and 0.05 to 5 mass% of a monomer unit having a hydroxyl group,

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 number of 10 to 15,

the thickness of the adhesive layer is 3-7 mu m.

2. The dicing tape according to claim 1, wherein the curing agent is a multifunctional isocyanate curing agent or a multifunctional epoxy curing agent.

3. The dicing tape according to claim 1 or 2, characterized in that the dicing tape has an adhesive force to a mirror surface of a silicon wafer measured according to JIS Z0237 of 5.0N/20mm or more.

4. A method for manufacturing an electronic component, comprising the steps of:

(a) a bonding step of bonding a dicing tape to the semiconductor wafer or substrate and the ring frame;

(b) a dicing step of dicing the semiconductor wafer or substrate to form a semiconductor chip or a semiconductor component;

(c) a light irradiation step of irradiating the dicing tape with active light;

(d) a spreading step of stretching the dicing tape to spread the interval between the semiconductor chips or the semiconductor components; and

(e) a pick-up step of picking up a semiconductor chip or a semiconductor component from the dicing tape;

the dicing tape is the dicing tape according to any one of claims 1 to 3.