JP2008085303A - Adhesive sheet for water jet laser dicing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet for achieving the working of an extremely thin semiconductor wafer or materials by securing the satisfactory adhesion of a wafer or the like in dicing, and preventing a chip or component from being peeled from an adhesive tape, and preventing the generation of such a failure as chip in the case of peeling the chip or IC component or the like after dicing under such circumstances that critical significance to the adhesive force of the adhesive sheet for dicing changes according to the change of the dicing technology of the semiconductor wafer or the like. <P>SOLUTION: An adhesive sheet for water jet laser dicing is configured by laminating an adhesive layer on a base film, wherein the adhesive constituting the adhesive layer is an energy radiation curing type adhesive, and the adhesive sheet has adhesive strength of at least 1.5 N/20 mm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an adhesive sheet for water jet laser dicing, and more particularly to an adhesive sheet for water jet laser dicing used for fixing a semiconductor wafer and / or a semiconductor-related material when dicing with a water jet laser. .

  Conventionally, semiconductor wafers, semiconductor-related materials, and the like are separated into chips and IC components by cutting using a rotary blade known as a dicing blade. In this dicing process, usually, in order to fix a semiconductor wafer or the like, first, it is adhered to an adhesive tape called a dicing tape or the like. Then, after the semiconductor wafer or the like is cut into chips, it is peeled off from the adhesive tape by a pickup.

  However, the chips cut by this method may cause die fly due to physical stress caused by the dicing blade, or defects such as cracking and chipping may occur. There has been a problem of reducing productivity. For this purpose, attempts have been made to make the adhesive force of the adhesive tape stronger, but it has become a more serious problem due to recent downsizing of electronic devices and increasing demand for thinner wafers. .

  On the other hand, the enhancement of the adhesive strength of the adhesive tape makes it difficult to peel off the chips after dicing, and in some cases causes chipping of the chips. In addition, the contaminants on the wafer and the like are strongly adhered by the adhesive tape, which causes a problem of contaminating the dicing apparatus.

  Therefore, as an alternative to cutting technology for semiconductor wafers using dicing blades, a dicing method using a laser beam, particularly cutting, drilling, welding, marking and peeling using a laser beam guided by a liquid jet. A material processing method based on the above has been proposed (for example, Patent Document 1). In this method, since the wafer or the like is only exposed to the water flow from above, die fly or the like due to physical stress caused by the rotating blade can be prevented.

Moreover, in the cutting method using this laser technology, there is a problem that chips and the like are easily peeled off from the adhesive tape that fixes them due to the use of water flow. A pressure-sensitive adhesive sheet that can be suitably used has been proposed (for example, Patent Document 2).
WO95 / 32834 JP 2001-316648 A

  The present invention is eager to process a semiconductor wafer and / or a semiconductor-related material, which is made thinner, by water jet laser dicing into a smaller and thinner chip or IC component, and further, with the transition of dicing technology. In the situation where the critical significance for the adhesive force of the adhesive sheet for dicing is changing, while ensuring good adhesion of the wafer and the like during dicing, while preventing the chip or parts from peeling from the adhesive tape, It is an object of the present invention to provide an adhesive sheet capable of processing an extremely thin semiconductor wafer or material without causing defects such as chipping in peeling of chips or IC components after dicing.

The water jet laser dicing pressure-sensitive adhesive sheet of the present invention is a water jet laser dicing pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is laminated on a base film, and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is an energy beam curable type. It is an adhesive, and the adhesive sheet has an adhesive strength of 1.5 N / 20 mm or more.
In this pressure-sensitive adhesive sheet for water jet laser dicing, the base film preferably has perforations and has a porosity of 3 to 90% or includes a layer made of polyolefin.

Further, the perforations preferably have a diameter of 5 to 800 μm or a size of 25 μm ^{2 to} 3.0 mm ² .
Furthermore, the pressure-sensitive adhesive is preferably made of a rubber-based or acrylic pressure-sensitive adhesive.
Moreover, it is preferable to have an elongation rate exceeding 100% or to have a tensile strength exceeding 0.1 N / 10 mm.
Furthermore, it is preferable that the adhesive strength after energy beam irradiation is less than 0.2 N / 20 mm.

  According to the water jet laser dicing pressure-sensitive adhesive sheet of the present invention, it is eager to process a thinner semiconductor wafer and / or semiconductor-related material into a smaller and thinner chip or IC component, and dicing technology. In the situation where the critical significance of the adhesive strength of the dicing adhesive sheet has changed with the transition of the chip, the chip or components should be peeled from the adhesive tape while ensuring good adhesion of the wafer during dicing. Can be prevented. Further, it is possible to provide an adhesive sheet capable of processing an extremely thin semiconductor wafer or material without causing defects such as chipping in peeling of chips or IC components after dicing.

  The water jet laser dicing pressure-sensitive adhesive sheet of the present invention mainly comprises a base film and a pressure-sensitive adhesive layer disposed thereon. Here, the pressure-sensitive adhesive sheet for water jet laser dicing is used for dicing using a laser beam guided by a liquid flow (usually a water flow), and a liquid resulting from the liquid flow at the time of dicing, for example, a predetermined pressure It refers to a pressure-sensitive adhesive sheet that can release the liquid in the case where the above liquid flow is directly or indirectly applied from the pressure-sensitive adhesive layer side to the pressure-sensitive adhesive sheet from one surface side to the other surface side. The predetermined pressure at this time can usually be about several MPa or more.

The pressure-sensitive adhesive layer is constituted by a pressure-sensitive adhesive layer applied to one surface of the base film. The pressure-sensitive adhesive is suitably a type of pressure-sensitive adhesive that is cured by irradiation with energy rays. Thereby, the peelability from the workpiece can be easily performed. As energy rays, for example, those having various wavelengths such as ultraviolet rays, visible rays, infrared rays and the like can be used. However, a laser beam used for dicing is an oscillation wavelength of 400 nm or less, for example, a KrF excimer laser having an oscillation wavelength of 248 nm. 308nm XeCI excimer laser, YAG laser third harmonic (355nm), fourth harmonic (266nm), or more than 400nm oscillation wavelength, for example, can absorb light in the ultraviolet region via multiphoton absorption process And a laser with a pulse width of 1e- ⁹ seconds (0.000000001 seconds) or less, such as a titanium sapphire laser with a wavelength of about 750-800 nm, which can be cut with a width of 20 μm or less by multiphoton absorption ablation. To the laser beam irradiation of the dicing equipment used It is preferable to use an adhesive that does not cure me.

As a material for forming the pressure-sensitive adhesive layer, known pressure-sensitive adhesives including (meth) acrylic polymers, rubber-based polymers and the like can be used, and (meth) acrylic polymers are particularly preferable. This makes it possible to cure without adding a special monomer / oligomer component for energy ray curing.
Examples of the rubber-based polymer may include natural rubber (for example, polyisoprene) and synthetic rubber (for example, styrene-butadiene rubber, polybutadiene-based, butadiene-acrylonitrile-based, chloroprene-based rubber, etc.).

  Examples of the monomer component constituting the (meth) acrylic polymer include, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an isobutyl group, a pentyl group, an isopentyl group, and a hexyl group. Group, heptyl group, cyclohexyl group, 2-ethylhexyl group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, lauryl group, tridecyl group, tetradecyl group, stearyl group, octadecyl group, and Examples thereof include alkyl acrylate or alkyl methacrylate having a linear or branched alkyl group having 30 or less carbon atoms, preferably 4 to 18 carbon atoms, such as a dodecyl group. These alkyl (meth) acrylates may be used alone or in combination of two or more.

  Other monomer components include, for example, acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid-containing monomers, anhydrous Acid anhydride monomers such as maleic acid and itaconic anhydride, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6- (meth) acrylic acid Hydroxyl groups such as hydroxyhexyl, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate Mo , Sulfones such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate and (meth) acryloyloxynaphthalene sulfonic acid Acid group-containing monomers, phosphate group-containing monomers such as 2-hydroxyethylacryloyl phosphate, (meth) acrylamide, (meth) acrylic acid N-hydroxymethylamide, (meth) acrylic acid alkylaminoalkyl esters (for example, dimethylaminoethyl Methacrylate, t-butylaminoethyl methacrylate, etc.), N-vinylpyrrolidone, acryloylmorpholine, vinyl acetate, styrene, acrylonitrile and the like. These monomer components may be used alone or in combination of two or more.

  Moreover, you may use a polyfunctional monomer arbitrarily for the purpose of bridge | crosslinking of a (meth) acrylic-type polymer. Examples of polyfunctional monomers include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and pentaerythritol di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Examples include epoxy (meth) acrylate, polyester (meth) acrylate, and urethane (meth) acrylate. These polyfunctional monomers may be used alone or in combination of two or more. The amount of the polyfunctional monomer used is preferably 30% by weight or less, more preferably 20% by weight or less of the total monomer components from the viewpoint of adhesive properties and the like.

Furthermore, it is preferable to use a monomer and / or an oligomer having an energy ray-curable functional group such as a carbon-carbon double bond.
Examples of the monomer / oligomer include urethane (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipenta. Examples include erythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 1,4-butylene glycol di (meth) acrylate. These may be used alone or in combination of two or more. These blending amounts are not particularly limited, but in consideration of tackiness, it is about 5 to 500 parts by weight with respect to 100 parts by weight of the base polymer such as (meth) acrylic polymer constituting the pressure-sensitive adhesive. It is preferable that it is about 70 to 150 parts by weight.

  Moreover, it is preferable to use a photoinitiator. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α-methylacetophenone, methoxyacetophenone, and 2,2-dimethoxy-2-phenyl. Acetophenone compounds such as acetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1, benzoin ethyl ether, benzoin isopropyl Benzoin ether compounds such as ether and anisoin methyl ether, α-ketol compounds such as 2-methyl-2-hydroxypropylphenone, ketal compounds such as benzyldimethyl ketal, 2-naphthalenesulfonyl chloride Aromatic sulfonyl chloride compounds such as Lido, photoactive oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime, benzophenone, benzoylbenzoic acid, 3,3′-dimethyl Benzophenone compounds such as -4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2 Thioxanthone compounds such as 1,4-diethylthioxanthone and 2,4-diisopropylthioxanthone, camphorquinone, halogenated ketone, acyl phosphinoxide and acyl phosphonate. These may be used alone or in combination of two or more. The blending amount of the photopolymerization initiator is preferably about 0.1 to 10 parts by weight, more preferably about 0.5 to 5 parts by weight with respect to 100 parts by weight of the base polymer constituting the pressure-sensitive adhesive. .

Furthermore, in order to increase the weight average molecular weight of the base polymer, a crosslinking agent may optionally be added. Examples of the crosslinking agent include polyisocyanate compounds, epoxy compounds, aziridine compounds, melamine resins, urea resins, anhydrous compounds, polyamines, and carboxyl group-containing polymers. These may be used alone or in combination of two or more. In the case of using a crosslinking agent, the amount used thereof is generally about 0.01 to 5 parts by weight with respect to 100 parts by weight of the base polymer, considering that the peeling adhesion does not decrease too much. preferable.
In addition to the above components, additives such as conventionally known tackifiers, anti-aging agents, fillers, colorants and the like can be optionally contained.

  The acrylic polymer is prepared, for example, by applying a known method such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method to one or more monomers or a mixture thereof. Can do. Of these, the solution polymerization method is preferable. Examples of the solvent used here include polar solvents such as ethyl acetate and toluene. The solution concentration is usually about 20 to 80% by weight.

  In preparing the polymer, a polymerization initiator may be used. Examples of the polymerization initiator include peroxides such as hydrogen peroxide, benzoyl peroxide, and t-butyl peroxide. Although it is desirable to use it alone, it may be used as a redox polymerization initiator in combination with a reducing agent. Examples of the reducing agent include ionized salts such as sulfite, bisulfite, iron, copper, and cobalt salts, amines such as triethanolamine, and reducing sugars such as aldose and ketose. 2,2′-azobis-2-methylpropioaminate, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis-N, N′-dimethyleneisobutylamidine acid An azo compound such as a salt, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methyl-N- (2-hydroxyethyl) propionamide may be used. These may be used alone or in combination of two or more.

The reaction temperature is usually about 50 to 85 ° C., and the reaction time is about 1 to 8 hours.
In particular, the acrylic polymer preferably has a low content of low molecular weight substances from the viewpoint of preventing contamination of the workpiece, and the acrylic polymer has a number average molecular weight of 300,000 or more, more preferably 800,000 to 3 million. The degree is preferred.

  The thickness of the pressure-sensitive adhesive layer can be adjusted as appropriate within the range where it does not peel from the workpiece, but it is possible to ensure sufficient adhesive strength, and after removing the semiconductor wafer from the tape, the wafer, etc. From the viewpoint that it is possible to prevent undesirable adhesive residue from remaining on the back surface of the adhesive layer and to allow water to pass through easily by cutting the adhesive layer, usually about 5 to 300 μm, preferably about 10 to 100 μm, More preferably, it is about 20-50 micrometers.

  Note that the pressure-sensitive adhesive layer may contain perforations, as will be described later. The perforations can be formed by any of the methods described below for the base film. The perforations may be formed simultaneously with the perforation of the base film, or may be formed in a separate process.

  As the base film, synthetic resin, for example, polyolefin such as polyethylene and polypropylene (specifically, low density polyethylene, linear low density polyethylene, high density polyethylene, stretched polypropylene, non-stretched polypropylene, ethylene-propylene copolymer) , Ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester copolymer, etc.), polyethylene terephthalate, polyurethane, EVA, polytetrafluoroethylene, polyvinyl chloride, Films of polymers containing rubber components such as polyvinylidene chloride, polyamide, acetal resin, polystyrene, polycarbonate, fluororesin, styrene-butadiene copolymer; PP, PVC, PE, PU, PS, PO or PET, etc. Polymer fibers, synthetic fibers such as rayon or cellulose acetate, cotton, nonwoven and woven fabric made of inorganic fibers such as natural fibers and glass fibers or carbon fibers such as silk or wool, and the like. These may be a single layer or a multilayer structure of two or more layers. Especially, it is preferable to include the layer which consists of polyolefin or consists of polyolefin.

  The base film has perforations that are penetrated in the thickness direction of the base film or in which a plurality of holes are continuous. The perforations may be formed regularly or irregularly on the base film. If the substrate film material consists of fibers, the perforations are obtained naturally as a result of the fiber-fiber gap, making the substrate film porous (although it may also include artificial perforations). When the base film is made of a resin, perforation can be artificially introduced.

  The base film can be perforated by a known through hole forming method. For example, mechanical, chemical and / or thermal methods commonly known in the art are included. Examples of the method for mechanically perforating the base film include punching with a press or a rotating roll, laser treatment, and water jet treatment. Furthermore, you may contain an inorganic particle in a base film at the time of manufacture of a base film. When the film is expanded, some of the particles are broken and holes can be formed in the film. Examples of the chemical perforation method include a method of forming a hole by adding a foaming agent to the base film material and foaming it. In another chemical method, a substrate film is processed into a sheet using a supporting polymer and a compound that is readily soluble in a solvent, and then the substrate film is immersed in a solvent followed by drying and swelling. By doing so, perforations can be formed.

The shape of the perforations in the substrate film may be any shape that allows water to escape, for example, it may be irregular, as in the case of fiber-to-fiber gaps, and may be circular, square, triangular, diamond-shaped, star-shaped. For example, various shapes may be used. The size of the perforations (pore size) measured with a microscope is usually 3.0 mm ² or less, 25 μm ^{2 to} 3.0 mm ² , preferably 0.001 to 3.0 mm ² , more preferably 0.1 to 0.1 mm ² . 2.0 mm ^2, most preferably 0.2~1.1mm ^2. When the hole is circular, the diameter is preferably 5 μm to 0.80 mm, 0.17 to 0.80 mm, and more preferably 0.25 to 0.59 mm. When the perforations are square, triangle or rhombus, the length of one side is preferably 5 μm to 1.40 mm, 0.30 to 1.40 mm, and more preferably 0.45 to 1.00 mm. The pore density is preferably more than 100,000 / m ² , more preferably 300000 to 700000 / m ² . The hole density is calculated from the pitch interval in the length direction and the lateral direction.

The base film has good water permeability, is less likely to cause chip peeling from the adhesive sheet and / or foreign matter mixing between the sheet and the chip, and further ensures the mechanical strength of the sheet and smoothness of the sheet. It is preferable to have a porosity of about 3 to 90% from the viewpoint of preventing the decrease in the thickness and ensuring the fixation between the base film and the pressure-sensitive adhesive. In particular, in the case of an artificial hole, it is preferably about 3 to 60%, about 10 to 55%, or about 20 to 50%. The porosity in this case can be calculated from the pore size and the pore density. That means
Porosity = (pore size) × (pore density) × 100%.

In the case of natural pores made of fibers or the like, the porosity is preferably 10 to 80%, more preferably 20 to 70%. In this case, the porosity can be calculated from the weight per unit area, the material density, and the thickness of the base film. That means
Porosity = (weight per unit area of base film) / (material density) / (thickness of base film) × 100%.

  The base film may be subjected to corona discharge treatment, flame treatment, plasma treatment, sputter etching treatment or undercoating (for example, primer), surface treatment such as fluorine treatment, degreasing treatment with a chemical solution, and the like. This is to improve the adhesion with the adhesive. Especially, it is preferable that the undercoat process is performed. The thickness of the base film is preferably from 10 to 400 μm, more preferably from 30 to 250 μm, from the viewpoint of preventing sheet breakage or cutting during processing of a semiconductor wafer or the like and reducing the manufacturing cost.

  The pressure-sensitive adhesive sheet of the present invention can be formed by a method for producing a tape known in the art. For example, first, a base film is prepared. This base film has perforations and a porosity of about 3 to 90%. The perforations may be formed after coating the base film with an adhesive. Subsequently, an adhesive is laminated | stacked on a base film. In this case, the substrate film may be coated directly, or a transfer coating method in which an adhesive is coated on a process material coated with a release agent and dried, and then the adhesive is laminated on the substrate film. It may be laminated using, or a pressure-sensitive adhesive may be roll laminated on the base film. These coatings can utilize various methods such as reverse roll coating, gravure coating, curtain spray coating, die coating, extrusion and other industrially applied coating methods.

  The pressure-sensitive adhesive sheet of the present invention has an adhesive strength of 1.5 N / 20 mm or more, more preferably 3 N / 20 mm or more. Furthermore, it is more preferable that it is less than 10N / 20mm and less than 8N / 20mm. In other words, along with the transition of dicing technology to water jet laser technology, the critical significance of the adhesive strength of the dicing adhesive sheet has changed, and as a result, the wafer at the time of dicing is also affected by weaker adhesive strength. It is possible to ensure good adhesion such as, and to prevent the chip or component from peeling from the adhesive tape. In addition, by reducing the initial adhesive strength, the adhesive strength of the adhesive after energy beam irradiation can be reduced effectively, quickly and easily, and defects such as chipping or IC component chipping during pickup can be eliminated. Can be reduced.

  Here, the adhesive strength is a value when measured on a Si mirror wafer under the conditions of a measurement temperature of 23 ± 3 ° C., a peeling angle of 180 °, and a peeling speed of 300 mm / min (according to ASTM D1000). is there.

The adhesive strength after energy beam irradiation is preferably less than 0.2 N / 20 mm, and more preferably less than 0.18 N / 20 mm.
The pressure-sensitive adhesive sheet of the present invention can be particularly suitably used when a workpiece, that is, a semiconductor wafer or the like is diced into chips having a smaller area. For example, individual chips or component size after dicing is less than 9 mm ^2, 6.25 mm ² or less, 4 mm ² or less, 2.25 mm ² or less, 1 mm ² or less, 0.6 mm ² or less, further 0.25 mm ² or less It is preferable that

Moreover, it is preferable that the adhesive sheet of this invention has the elongation rate which exceeds 100%, More preferably, it is 150%. This is because, by extending the pressure-sensitive adhesive sheet, it becomes possible to easily pick a chip or the like from the pressure-sensitive adhesive sheet after the dicing process.
Further, the pressure-sensitive adhesive sheet preferably has a tensile strength exceeding 0.1 N / 10 mm, and more preferably higher than 0.3 N / 10 mm. This is to avoid breakage and / or cutting of the adhesive sheet itself.

Elongation rate and tensile strength can be measured with a tensile tester using, for example, a sample having a length of 5.0 cm and a width of 20 mm. The tensile speed during the test is 300 mm / min at room temperature (according to ASTM D1000). The elongation percentage can be calculated as follows.
Elongation rate = (length at break-original length) / (original length) × 100%. Further, the tensile strength is a measured value at break.

Examples of the pressure-sensitive adhesive sheet for water jet laser dicing of the present invention will be described in detail below. (Preparation of adhesive)
Example 1
70 parts by weight of butyl acrylate (Tg in homopolymer = −54 ° C.), 30 parts by weight of 2-ethylhexyl acrylate (Tg in homopolymer = −85 ° C.) and acrylic acid (Tg in homopolymer = 106 ° C.) In a solution containing an acrylic copolymer having a weight average molecular weight of 1,000,000 obtained by copolymerizing 10 parts by weight in ethyl acetate by a conventional method, photopolymerizable oligomer UV1700B (manufactured by Nippon Synthetic Chemical Co., Ltd.) 80 Parts by weight, photopolymerization initiator (trade name “Irgacure 184”, manufactured by Ciba Specialty Chemicals), melamine resin, (trade name “Super Becamine J-820-60N” (produced by Dainippon Ink) 10 An acrylic radiation curable pressure-sensitive adhesive solution was obtained by adding 5 parts by weight of a polyisocyanate compound (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.).

Example 2
Obtained by copolymerizing 95 parts by weight of 2-ethylhexyl acrylate (Tg in homopolymer = -85 ° C.) and 5 parts by weight of acrylic acid (Tg in homopolymer = 106 ° C.) in a conventional manner. In addition, a solution containing an acrylic copolymer having a weight average molecular weight of 700,000 was mixed with 60 parts by weight of penerythritol triacrylate (viscosity 1 Pa · sec at 25 ° C.), a photopolymerization initiator (trade name “Irgacure 651”, Ciba 3 parts by weight of Specialty Chemicals) and 5 parts by weight of a polyisocyanate compound (trade name “Coronate L”, manufactured by Nippon Polyurethane) were added to obtain an acrylic radiation curable pressure-sensitive adhesive solution.

Example 3
60 parts by weight of methyl acrylate (Tg in homopolymer = 8 ° C.), 30 parts by weight of butyl acrylate (Tg in homopolymer = −54 ° C.) and 10 parts by weight of acrylic acid (Tg in homopolymer = 106 ° C.) Radiation curable obtained by reacting pentaerythritol triacrylate with diisocyanate in a solution containing an acrylic copolymer having a weight average molecular weight of 800,000 obtained by copolymerizing in a conventional manner with ethyl acetate 60 parts by weight of an oligomer (viscosity of 10 Pa · sec at 25 ° C.), 3 parts by weight of a photopolymerization initiator (trade name “Irgacure 651”, manufactured by Ciba Specialty Chemicals) and a polyisocyanate compound (trade name “Coronate L”), 2 parts by weight) (manufactured by Nippon Polyurethane Co., Ltd.) was added to obtain an acrylic radiation curable pressure-sensitive adhesive solution.

Example 4
50 parts by weight of methyl acrylate (Tg in homopolymer = 8 ° C.), 30 parts by weight of butyl acrylate (Tg in homopolymer = −54 ° C.) and 20 parts by weight of acrylic acid (Tg in homopolymer = 106 ° C.) Radiation curable obtained by reacting pentaerythritol triacrylate with diisocyanate in a solution containing an acrylic copolymer having a weight average molecular weight of 800,000 obtained by copolymerizing in a conventional manner with ethyl acetate 60 parts by weight of an oligomer (viscosity of 10 Pa · sec at 25 ° C.), 3 parts by weight of a photopolymerization initiator (trade name “Irgacure 651”, manufactured by Ciba Specialty Chemicals) and a polyisocyanate compound (trade name “Coronate L”), 2 parts by weight) (manufactured by Nippon Polyurethane Co., Ltd.) was added to obtain an acrylic radiation curable pressure-sensitive adhesive solution.

Comparative Example 1
100 parts by weight of acrylic resin Leocoat 1020 (Daiichi Race Co., Ltd.), 30 parts by weight of dioctyl phthalate and 10 parts by weight of melamine resin (trade name “Super Becamine J-820-60N” (Dainippon Ink Co., Ltd.)) The copolymer was copolymerized by a conventional method to obtain an acrylic pressure-sensitive adhesive solution.

Comparative Example 2
100 parts by weight of acrylic resin Leocoat 1020 (Daiichi Lace Co., Ltd.), 20 parts by weight of dioctyl phthalate and 8 parts by weight of melamine resin (trade name “Super Becamine J-820-60N” (Dainippon Ink Co., Ltd.)) The copolymer was copolymerized by a conventional method to obtain an acrylic pressure-sensitive adhesive solution.

(Base film)
A 200 μm-thick nonwoven sheet made of polypropylene fibers having a size of 0.1 to 0.3 mm and made of polypropylene fibers with a porosity of 30% was used.

(Preparation of adhesive sheet for dicing)
The pressure-sensitive adhesive solutions prepared in the above examples were each applied to a polypropylene nonwoven sheet and heated and crosslinked at 80 ° C. for 10 minutes to form a pressure-sensitive adhesive layer having a thickness of 10 μm.
Subsequently, a separator was bonded to the surface of the pressure-sensitive adhesive layer to produce an ultraviolet curable or pressure-sensitive pressure-sensitive dicing pressure-sensitive adhesive sheet.

(Adhesive strength for peeling silicon wafers)
The dicing pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut into strips with a width of 25 mm, and the silicon mirror wafer surface (manufactured by Shin-Etsu Semiconductor Co., Ltd .; CZN <100> 2.5-) at 23 ° C. (room temperature). 3.5 (4 inches)). After standing at room temperature for 30 minutes, the adhesive strength was measured by peeling 180 ° (tensile speed 300 mm / min) in a thermostatic chamber at 23 ° C.
Moreover, after sticking on the silicon mirror wafer surface, the peeling adhesive strength after irradiation with ultraviolet rays at an irradiation intensity of 500 mJ / cm ² for 20 seconds was also measured.

(Dicing conditions)
The die fly rate (chip fly rate,%) when dicing was performed under the following conditions was calculated.
Laser wavelength: 532 nm
Dicing speed: 50mm / s
Laser diameter: 50 μm
Water jet pressure: 8MPa
Chip size: 0.3 mm x 0.3 mm, 1 mm x 1 mm, 2.5 mm x 2.5 mm, 5 mm x 5 mm
Wafer size: 13.7 cm (5 inches)
Wafer thickness: 100 μm

(Pickup conditions)
The semiconductor chip after dicing was irradiated with ultraviolet rays (irradiation time: 20 seconds, irradiation intensity: 500 mJ / cm ² ) from the back surface of the sheet. Furthermore, 50 arbitrary semiconductor chips were picked up (peeled) under the following conditions, the number of chips successfully picked up was counted, and the pick-up success rate (%) was calculated.

Equipment conditions Die bonder: NEC Machinery CPS-100
Number of pins: 4 Pin spacing: 3.5 x 3.5 mm
Pin tip curvature: 0.250mm
Pin push-up amount: 0.50mm
Adsorption holding time: 0.2 seconds Extraction amount: 3 mm
These results are shown in Table 1.

In addition, as comparative examples 3-6, the adhesive sheet similar to Examples 1-4 was produced except having used the thing which does not perforate in a base film, and dicing process was performed on the conditions similar to said dicing conditions, respectively. In either case, there was no escape for water flow, and the chip bounced or dicing could not be performed due to water overflowing on the wafer surface and entering between the wafer and the sheet.

  As is clear from Table 1, in the examples where the adhesive strength of the adhesive sheet is 1.5 N / 20 mm or more and the energy ray curable adhesive is used, almost no die fly occurs, and the success rate of the pickup is Also good results were obtained. Moreover, even when the water jet pressure is considerably strong, no deterioration was observed in the adhesive strength during dicing due to the easy removal of water.

  On the other hand, it was confirmed that when the adhesive strength was too weak, die fly was likely to occur, and when the adhesive strength was not very weak at the time of pick-up, the chip was likely to be chipped or cracked.

  The pressure-sensitive adhesive sheet for water jet laser dicing of the present invention can be diced by a laser beam guided by a liquid flow, that is, a semiconductor-related material (for example, a semiconductor wafer, a BGA package, a printed circuit, a ceramic plate, a liquid crystal Not only glass parts for devices, sheet materials, circuit boards, glass substrates, ceramic substrates, metal substrates, semiconductor laser light emitting / receiving element substrates, MEMS substrates, semiconductor packages, etc.), but also for all kinds of materials, Can be used widely.

Claims (9)

A water jet laser dicing pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is laminated on a base film,
The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive layer is an energy ray-curable pressure-sensitive adhesive, and the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive strength of 1.5 N / 20 mm or more.   The pressure-sensitive adhesive sheet for water jet laser dicing according to claim 1, wherein the base film has perforations and has a porosity of 3 to 90%.   The adhesive sheet for water jet laser dicing according to claim 1, wherein the base film includes a layer made of polyolefin.   The pressure-sensitive adhesive sheet for water jet laser dicing according to any one of claims 1 to 3, wherein the perforations have a diameter of 5 to 800 µm. The pressure-sensitive adhesive sheet for water jet laser dicing according to any one of claims 1 to 3, wherein the perforations have a size of 25 µm ^{2 to} 3.0 mm ² .   The water-jet laser dicing pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the pressure-sensitive adhesive comprises a rubber-based or acrylic pressure-sensitive adhesive.   The pressure-sensitive adhesive sheet for water jet laser dicing according to any one of claims 1 to 6, which has an elongation rate exceeding 100%.   The pressure-sensitive adhesive sheet for water jet laser dicing according to any one of claims 1 to 7, which has a tensile strength exceeding 0.1 N / 10 mm.   The adhesive sheet for water jet laser dicing according to any one of claims 1 to 8, wherein the adhesive strength after irradiation with energy rays is less than 0.2 N / 20 mm.