JP2008270505A - Adhesive sheet for water jet laser dicing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet capable of processing a very thin semiconductor wafer or material, without causing defects such as chipping of a chip or IC parts at peeling, by obtaining sufficient expandability when picking up after dicing while maintaining transmissivity of a liquid caused by a liquid flow, relating to a water jet laser dicing. <P>SOLUTION: An adhesive sheet for water jet laser dicing has an adhesive agent layer stacked on a base material film. The adhesive sheet is for water jet laser dicing, which has through holes, with voidage of 3-90% and elongation at break being 100% or higher. <P>COPYRIGHT: (C)2009,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 have been separated into chips and IC components by cutting using a rotating blade. In this dicing process, usually, the semiconductor wafer or the like is bonded to an adhesive sheet in order to fix it, and the wafer or the like is cut into chips and then peeled off from the adhesive sheet by a pickup.

  However, in this method, die fly occurs due to physical stress by the dicing blade, defects such as cracking and chipping occur, the quality of the chips and the like is reduced, and the productivity of this cutting method is also reduced. There was a problem. In particular, the demand for downsizing and thinning electronic devices in recent years has become a more serious problem.

  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.

In addition, in the cutting method using this laser technology, there is a problem that chips and the like are easily peeled off from the adhesive sheet for fixing them due to the use of a 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

  However, even if it is a pressure sensitive adhesive sheet that can be suitably used for water jet laser dicing, when the chip or the like is peeled off from the pressure sensitive adhesive sheet by picking up after dicing, it is adjacent that the expandability of the pressure sensitive adhesive sheet itself is insufficient. An appropriate space cannot be secured between the chips, and chip cracking and chipping may occur.

  The present invention, in water jet laser dicing, obtains sufficient expandability at the time of pick-up after dicing while maintaining the liquid permeability due to the liquid flow, and chipping at the time of chip or IC component peeling, etc. 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 the above defects.

The water jet laser dicing adhesive sheet of the present invention is a water jet laser dicing adhesive sheet in which an adhesive layer is laminated on a base film,
The pressure-sensitive adhesive sheet has a breaking elongation of 50% or more.
In this pressure-sensitive adhesive sheet for water jet laser dicing, the base film has perforations and has a porosity of 3 to 90%, is composed of a woven / knitted mesh film of fibers, or contains polyolefin, The average perforation size is preferably 10 μm ^{2 to} 3.0 mm ² .

  According to the water jet laser dicing pressure-sensitive adhesive sheet of the present invention, sufficient expandability can be obtained at the time of pickup after water jet laser dicing. As a result, it is possible to secure an appropriate space between adjacent chips when peeling chips or IC components, etc., without causing defects such as chipping due to contact between chips, impact due to pickup, etc. An adhesive sheet capable of processing a thin semiconductor wafer or material can be provided.

  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 water jet laser dicing adhesive sheet is used for dicing using a laser beam guided by a liquid flow (usually a water flow), and this liquid flow at the time of dicing, for example, a liquid flow of a predetermined pressure or higher. Refers to a pressure-sensitive adhesive sheet that allows the liquid in a case where the liquid is applied directly or indirectly from the pressure-sensitive adhesive layer side to the other surface side from the one surface side of the pressure-sensitive adhesive sheet. The predetermined pressure at this time can usually be about several MPa or more.

As the base film, a material and a composition that have a breaking elongation of about 50% or more, preferably about 100% or more when an adhesive sheet is formed, are suitable. Usually, the elongation at break means the elongation at break when a sample having a length of 5.0 cm and a width of 20 mm is used, and the tensile rate is 300 mm / min at room temperature (ASTM). According to D1000). The breaking elongation can be calculated as follows.
Elongation at break = (length at break-original length) / (original length) × 100%

  The elongation at break may be about 50% or more in one direction, but it is preferably about 50% or more with respect to a plurality of directions, preferably with respect to all directions. Here, all directions usually mean 360 °, but at least vertical (0-180 ° direction), horizontal (90-270 ° direction), diagonal (45-225 ° direction and 135-315 ° direction). ), It may be about 50% or more. Moreover, it is preferable to extend about 50% or more simultaneously at least in these directions. This is because, when the pressure-sensitive adhesive sheet is extended, chips and the like can be easily picked up from the adhesive sheet after the dicing process.

  Such materials include synthetic resins such as polyolefins such as polyethylene and polypropylene (specifically, low density polyethylene, linear low density polyethylene, high density polyethylene, stretched polypropylene, unstretched polypropylene, ethylene-propylene copolymer). Polymer, 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 rubber component-containing polymers such as polyvinylidene chloride, polyamide, acetal resin, polystyrene, polycarbonate, fluororesin, styrene-butadiene copolymer; PP, PVC, PE, PU, PS, PO or PET Polymer fibers, synthetic fibers such as rayon or cellulose acetate, cotton, mesh film made of inorganic fibers such as natural fibers and glass fibers or carbon fibers such as silk or wool, that is, like woven or knitted 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. As a result, it is possible to ensure both proper strength against laser dicing and expandability.

  Here, the woven fabric usually means a structure in which warp yarns and weft yarns intersect at a right angle or a predetermined angle, and are relatively in close contact with adjacent yarns and are connected in a plane, for example, plain weave, twill weave (oblique) Woven), satin weave, plain woven fabric and twill woven fabric. In addition, the knitted fabric usually means a structure composed of one or several yarns forming a loop, and a continuous loop of hooking the next yarn to the loop to form a new loop. Various structures such as flat knitting, rubber knitting, pearl knitting, etc., warp knitting (Denby knitting, Atlas knitting, coat knitting, etc.) can be mentioned. In particular, a knitted fabric is preferable because the elongation at break is large regardless of the type of fiber used, and the elongation at break can be easily adjusted by adjusting the size of the stitches.

  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 10 μm to 400 μm, more preferably 30 μm 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 base film has perforations that are penetrated in the thickness direction or in which a plurality of holes are continuous. The shape and size of the perforations may be any shape that allows water to escape. For example, the perforations may be irregular, square (for example, see FIG. 1 (a)), or circular (for example, FIG. 1 (b). ) And (c)), various shapes such as a triangle, a rhombus, and a star may be regularly arranged (for example, a lattice such as a square lattice or a triangular lattice). The size of the perforations as measured by microscope (pore size) is usually at 3.0 mm ² or less, for ^{example, 10μm 2 ~3.0mm 2, 25μm 2} ~3.0mm 2, preferably 0.001 mm ² to 3 .0mm ^2, more preferably 0.1mm ² ~2.0mm ^2, most preferably 0.2mm ² ~1.1mm ^2. If the hole is square, triangular or rhombic, the length of one side (e.g., in FIG. 1 (a), see _{R 1)),} for example, 0.005mm~1.40mm, 0.30mm~1.40mm It is preferable that it is 0.45 mm-1.00 mm. When the hole is circular, its diameter (see, for example, R ₂ and R ₃ in FIGS. 1B and 1C) is preferably 0.005 mm to 0.8 mm, 0.17 mm to 0.80 mm, and more. Preferably they are 0.25 mm-0.59 mm. The pore density is preferably more than 100,000 / m ² , more preferably 300000 / m ^{2 to} 700,000 / m ² . The pore density is calculated from the pitch interval in the length direction and the lateral direction (see D in FIGS. 1A to 1C).

The base film preferably has a porosity of about 3% to 90%. In particular, about 3% to 80%, about 3% to about 60%, about 10% to about 80%, about 10% to about 55%, and about about 20% to about 50% are preferable. Thereby, water permeability becomes favorable and it can prevent peeling of the chip | tip from an adhesive sheet and / or foreign material mixing between a sheet | seat and a chip | tip. Moreover, the mechanical strength of the tape can be secured, the tape smoothness can be prevented from being lowered, and the adhesion between the base film and the adhesive can be ensured. The porosity in this case can be calculated from the pore size and the pore density. That means
Porosity = (pore size) x (pore density) x 100%
It is.

The pressure-sensitive adhesive layer is constituted by a pressure-sensitive adhesive layer applied to one surface of the base film. This pressure-sensitive adhesive may be any of a pressure-sensitive type, a heat-sensitive type, and a photosensitive type, but is preferably 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 multi-photon absorption process In addition, a laser having a pulse width of 1e- ⁹ seconds (0.000000001 seconds) or less, such as a titanium sapphire laser having a wavelength of about 750 nm to 800 nm, which can be cut with a width of 20 μm or less by multiphoton absorption ablation. From the laser beam of the dicing machine used. It is preferable to use a cured without adhesive.

  As a material for forming the pressure-sensitive adhesive layer, a known pressure-sensitive adhesive including a rubber polymer, a (meth) acrylic polymer, and the like can be used, and a (meth) acrylic polymer is particularly preferable. As a result, even when a photosensitive pressure-sensitive adhesive is used, curing can be performed 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 a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an isobutyl group, an amyl group, an isoamyl 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, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, Dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, and urethane (meth) acrylate Etc., and the like. 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, when comprising a photosensitive adhesive, 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, anti-aging agents, and coloring agents can be optionally added.
The acrylic polymer is prepared, for example, by applying a known method such as a solution polymerization method, an emulsion polymerization method, a current 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 a sufficient adhesive strength, and after removing the semiconductor wafer etc. from the tape, the wafer etc. From the viewpoints of preventing an undesired adhesive residue from remaining on the back surface and allowing water to be easily passed by cutting the adhesive layer, about 1 to 50 μm and about 3 to 20 μm are more preferable. Thereby, at the time of dicing, resonance of the adhesive layer due to laser beam irradiation or vibration caused by the liquid flow can be minimized, the amplitude width can be suppressed, and chip cracking, chipping, and the like can be prevented. Moreover, the workpiece can be reliably fixed during dicing.

  As will be described later, the pressure-sensitive adhesive layer preferably includes perforations as in the case of the base film. The perforation can be formed by any of the methods described below for the base film, and the perforation of the base film and the pressure-sensitive adhesive layer is substantially the same by forming simultaneously with the perforation of the base film. preferable.

  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. 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 prepared base sheet may have perforations in the state of the base sheet, or may be formed after coating the base film with an adhesive.

  The pressure-sensitive adhesive sheet of the present invention preferably 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 adhesive strength of dicing adhesive tapes has changed. As a result, even when weaker adhesive strength is applied, wafers during dicing are changed. It is possible to ensure good adhesion such as, and to prevent the chip or component from peeling from the pressure-sensitive adhesive sheet. In addition, by reducing the initial adhesive force, it is possible to reduce defects such as chipping of chips or IC components during pickup. In particular, in the case of a photosensitive pressure-sensitive adhesive, the adhesive strength of the pressure-sensitive adhesive after irradiation with energy rays can be reduced effectively, rapidly and simply. In addition, it is preferable that the adhesive strength after irradiation with energy rays is less than 0.2 N / 20 mm, and further less than 0.18 N / 20 mm.

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.
Furthermore, the pressure-sensitive adhesive sheet preferably has a tensile strength exceeding 0.1 N / 20 mm, and more preferably higher than 0.3 N / 20 mm. This is to avoid breakage and / or cutting of the adhesive sheet itself. The tensile strength can be measured by a tensile tester, similarly to the breaking strength.

Examples of the pressure-sensitive adhesive sheet for water jet laser dicing of the present invention will be described in detail below.
Example 1
(Preparation of adhesive)
60 parts by weight of methyl acrylate, 35 parts by weight of 2-ethylhexyl acrylate and 5 parts by weight of acrylic acid were copolymerized in ethyl acetate by a conventional method. As a result, a solution containing an acrylic copolymer having a weight average molecular weight of 700,000 was obtained. Next, 100 parts by weight of an ultraviolet curable oligomer (viscosity at 25 ° C. of 10 Pa · sec) obtained by reacting a solution containing an acrylic copolymer with pentaerythritol triacrylate and diisocyanate, a photopolymerization initiator ( Add 3 parts by weight of the product name “Irgacure 651”, manufactured by Ciba Specialty Chemicals Co., Ltd.) and 2 parts by weight of a polyisocyanate compound (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.). An agent solution was obtained.

(Base film)
A base film was obtained by corona-treating a plain weave mesh film formed of polyvinyl chloride having a wire diameter of 90 μm and having a density of 100 × 100 / cm ² , a porosity of 3% and a thickness of 180 μm.
On the above-mentioned base film, the pressure-sensitive adhesive solution was applied so that the pressure-sensitive adhesive layer had a thickness of 10 μm to obtain a pressure-sensitive adhesive sheet.

Example 2
The same as Example 1 except that a base film formed of polyethylene terephthalate with a wire diameter of 50 μm and knitted into a flat knitting with a density of 50 × 50 / cm ² , a porosity of 90% and a thickness of 100 μm was used. Thus, an adhesive sheet was obtained.

Example 3
Similar to Example 1 except that a base film formed of polyethylene terephthalate with a wire diameter of 50 μm and knitted into a flat knitting with a density of 140 × 140 pieces / cm ² , a porosity of 50% and a thickness of 100 μm was used. Thus, an adhesive sheet was obtained.

Example 4
The same as Example 1 except that a base film formed of polyethylene terephthalate with a wire diameter of 90 μm and knitted into a flat knitting with a density of 100 × 100 / cm ² , a porosity of 1% and a thickness of 180 μm was used. Thus, an adhesive sheet was obtained.

Example 5
The same as Example 1 except that a base film formed of polyethylene terephthalate having a wire diameter of 50 μm and knitted into a flat knitting having a density of 50 × 50 / cm ² , a porosity of 95%, and a thickness of 100 μm was used. Thus, an adhesive sheet was obtained.

Comparative Example 1
Similar to Example 1 except that a base film formed of polyethylene terephthalate with a wire diameter of 50 μm and knitted into a flat knitting with a density of 140 × 140 pieces / cm ² , a porosity of 50% and a thickness of 100 μm was used. Thus, an adhesive sheet was obtained.

Comparative Example 2
Example 1 with the exception of using a base film formed of polyvinyl chloride having a wire diameter of 90 μm and knitted into a flat knitting having a density of 100 × 100 / cm ² , a porosity of 1%, and a thickness of 180 μm. Similarly, an adhesive sheet was obtained.

Comparative Example 3
The same as Example 1 except that a base film formed of polyethylene terephthalate having a wire diameter of 50 μm and knitted into a flat knitting having a density of 50 × 50 / cm ² , a porosity of 95%, and a thickness of 100 μm was used. Thus, an adhesive sheet was obtained.

(Dicing conditions)
After dicing under the following conditions, a silicon wafer was picked up, chip defects were observed, and the number of chips in which defects were confirmed was confirmed. Moreover, the damage to the mesh base material of a dicing line was observed with the optical microscope, and the case where damage was confirmed was made into the case where damage was not recognized.
Laser wavelength: 532 nm
Dicing speed: 50mm / s
Laser diameter: 50 μm
Water jet pressure: 8MPa
Chip size: 3mm x 3mm
Silicon wafer size: 13.7 cm (5 inches)
Silicon wafer thickness: 100 μm
These results are shown in Table 1.

As can be seen from Table 1, when the elongation at break was large, it was possible to expand well at the time of picking up after dicing, and no defects due to picking up occurred.
On the other hand, in Comparative Example 1, since the elongation at break was small, the expansion could not be performed satisfactorily, and as a result, defects due to the pickup occurred.

Further, when the porosity was in the range of 3% or more and 90% or less, the water jet smoothly passed through the base material, and the base material was not damaged.
On the other hand, in Comparative Example 2, since the porosity was low, the water jet did not smoothly pass through the base material, and damage to the base material was confirmed.
Moreover, in Comparative Example 3, since the porosity was too high, the strength of the base material was not sufficient, and damage to the base material was confirmed due to stress during dicing.

  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 equipment, sheet materials, circuit boards, glass substrates, ceramic substrates, metal substrates, semiconductor laser light emitting / receiving element substrates, MEMS substrates, semiconductor packages, etc.), but also all kinds of materials, Can be used widely.

It is the schematic for demonstrating the perforation pattern of the adhesive sheet for water jet laser dicing of this invention.

Explanation of symbols

D hole spacing R ₁ hole of one side length R ₂ of the _{R 3} pore diameter

Claims (5)

A water jet laser dicing pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is laminated on a base film,
The adhesive sheet for water jet laser dicing, wherein the adhesive sheet has a breaking elongation of 50% 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 pressure-sensitive adhesive sheet for water jet laser dicing according to claim 1, wherein the base film is a woven / knitted mesh film made of fibers.   The pressure sensitive adhesive sheet for water jet laser dicing according to any one of claims 1 to 3, wherein the base film contains polyolefin. The pressure-sensitive adhesive sheet for water jet laser dicing according to any one of claims 1 to 4, wherein the base film has an average perforation size of 10 µm ^{2 to} 3.0 mm ² .