JP2003007646A - Adhesive sheet for dicing and method of manufacturing cut chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dicing adhesive sheet for fixing various kinds of works to be cut by dicing, such as semiconductor components which prevents chipping in dicing and a method of manufacturing cut products of various kinds of works, such as semiconductor components by dicing with use of the dicing adhesive sheet. SOLUTION: The adhesive sheet comprises a viscoelastic layer (A), hardened on at least one side of a base film by an energy beam incident on the base film and an adhesive layer (B), laminated on the viscoelastic layer (A).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to hold an object to be cut such as a semiconductor wafer or a semiconductor package when cutting or dicing various substrates of semiconductor components into chips or packages. The present invention relates to a pressure-sensitive adhesive sheet for dicing. Further, by using the pressure-sensitive adhesive sheet for dicing, a semiconductor wafer is diced and divided into semiconductor elements for each pattern,
The present invention relates to a method of manufacturing various cut pieces of a cut object such as a semiconductor component by dividing various semiconductor packages including a semiconductor element inside.

[0002]

2. Description of the Related Art A semiconductor wafer on which a predetermined circuit pattern such as an IC has been formed is back-polished to, for example, 0.1 to 0.1.
After making the thickness as thin as possible to about 4 mm, dicing is performed to a predetermined chip size with a rotary blade such as a system in which a blade for dispersing metal particles is rotated. In the dicing process, the wafer is fixed by a pressure-sensitive adhesive sheet for dicing, which is formed by laminating a pressure-sensitive adhesive layer on a base film, and cut to reach the base portion of the pressure-sensitive adhesive sheet for dicing (5 to 5).
A method of performing full-cutting of the wafer by performing a process of about 30 μm) is generally known.

When the dicing process is performed, a problem called chipping (several μm to several mm) occurs on the back side of the cut chip, which is a problem. In recent years, along with the widespread use of IC cards and the like, the thickness of semiconductor wafers has been reduced, and metal processing on the wafer surface has progressed.
There is a problem that chipping of a semiconductor element causes a significant reduction in strength of the semiconductor element, resulting in a significant decrease in its reliability.

This problem is caused by, for example, Japanese Patent Laid-Open No. 10-24.
By using a pressure-sensitive adhesive sheet for dicing in which a specific pressure-sensitive adhesive layer is laminated as described in 2086 gazette,
The amount of chips can be reduced. However, even with the dicing pressure-sensitive adhesive sheet, depending on the type of the base film, there is a problem that the backside of the chip becomes large and the defective rate significantly increases. Further, it has been proposed to reduce the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for dicing in order to solve the above-mentioned problems. However, if the pressure-sensitive adhesive layer is made thin, it is not possible to sufficiently fix an object to be cut, such as a semiconductor wafer whose back surface is ground or a package sealed with epoxy resin, which has surface irregularities.

[0005]

SUMMARY OF THE INVENTION The present invention provides a pressure-sensitive adhesive sheet for dicing, which is used for fixing various cut objects such as semiconductor parts when dicing, and which can prevent chipping during dicing. Further, it is an object of the present invention to provide a method for producing cut pieces of various cut objects such as semiconductor parts by performing dicing using the pressure-sensitive adhesive sheet for dicing.

[0006]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that the above-mentioned object can be achieved by the pressure-sensitive adhesive sheet for dicing, and have completed the present invention. It was

That is, according to the present invention, the viscoelastic layer (A) cured by energy rays from the base film side and then the adhesive layer (B) are laminated in this order on at least one side of the base film. A characteristic adhesive sheet for dicing.

The viscoelastic layer (A) of the pressure-sensitive adhesive sheet for dicing is a cured product obtained by curing a viscoelastic body with energy rays, and forms a layer harder than a general pressure-sensitive adhesive layer (B). Therefore, the cut body such as a semiconductor component is less likely to be deformed. By limiting the cuts during dicing to the viscoelastic layer (A), chipping on the backside of the chip can be suppressed regardless of the type of the base material film, and defective products are not produced. The cut body can be cut normally. On the other hand, since the adhesive layer (B) does not lose the adhesiveness, it is possible to fix the semiconductor parts during dicing and prevent the cut parts from scattering due to the stress during dicing.

In the pressure-sensitive adhesive sheet for dicing, the energy ray-cured viscoelastic layer (A) contains an energy containing a composition of an organic viscoelastic body and an energy ray-curable compound and / or an energy ray-curable resin. It can be formed by a cured product of a line-curable pressure-sensitive adhesive.

In the pressure-sensitive adhesive sheet for dicing, the viscoelastic layer (A) cured by energy rays preferably has a storage elastic modulus at 23 ° C. in the range of 1 × 10 ⁷ to 1 × 10 ¹⁰ Pa.

The viscoelastic layer (A) having the storage elastic modulus can effectively suppress chipping. As the storage elastic modulus increases, the amount of blade wear increases and the chipping occurrence rate tends to increase. Therefore, the storage elastic modulus is more preferably 1 × 10 ¹⁰ Pa or less. On the other hand, as the storage elastic modulus decreases, the chipping occurrence rate tends to increase, so that the storage elastic modulus is more preferably 1 × 10 ⁷ or more.

In the pressure-sensitive adhesive sheet for dicing, the viscoelastic layer (A) cured by energy rays has a thickness of 5 to 3
It is preferably 00 μm.

Viscoelastic layer (A) cured by energy rays
The total thickness with respect to the pressure-sensitive adhesive layer (B) is preferably larger than the cutting depth of the cutting blade. On the other hand, if the thickness of the viscoelastic layer (A) is too large, the workability of sticking to the wafer tends to deteriorate. From these points, the viscoelastic layer (A)
The thickness is usually 5 to 300 μm, especially 10 to 100
μm, and more preferably 20 to 50 μm.

In the pressure-sensitive adhesive sheet for dicing, it is preferable that the thickness of the viscoelastic layer (A) is equal to or larger than the thickness of the pressure-sensitive adhesive layer (B).

The thickness of the pressure-sensitive adhesive layer (B) is preferably equal to or larger than the thickness of the viscoelastic layer (A) from the viewpoints of preventing chipping of the chip cut surface and compatibility of fixing and holding the wafer. Adhesive layer (B)
Is preferably about 1 to 50 μm, particularly 2 to 30 μm, and further preferably 2 to 15 μm.

Further, according to the present invention, when the object to be cut is placed on the surface of the pressure-sensitive adhesive layer (B) of the pressure-sensitive adhesive sheet for dicing and the object to be cut is diced, the pressure-sensitive adhesive sheet for dicing is subjected to the dicing. The present invention relates to a method for producing a cut piece, wherein the cut is made up to the viscoelastic layer (A) and the base film is not cut.

In the pressure-sensitive adhesive sheet for dicing of the present invention, the pressure-sensitive adhesive layer (B) is attached to a semiconductor component or the like which is the object to be cut, and the object to be cut is fixed for dicing. The base film does not have to be cut by setting up to the viscoelastic layer (A). Therefore, it is possible to normally cut the object to be cut regardless of the base film, without causing defects such as chipping on the back side of the chip.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive sheet for dicing according to the present invention will be described in detail below with reference to FIG. As shown in FIG. 1, in the pressure-sensitive adhesive sheet for dicing of the present invention, the viscoelastic layer (A) is provided on the base film 1, and then the pressure-sensitive adhesive layer (B) is laminated on the viscoelastic layer (A). Has been done. Also,
If necessary, the separator 2 is provided on the pressure-sensitive adhesive layer (B). In FIG. 1, the viscoelastic layer (A) and the pressure-sensitive adhesive layer (B) are provided on one side of the base film 1, but they can be formed on both sides of the base film 1. The pressure-sensitive adhesive sheet for dicing may have a shape corresponding to the planar shape of a substrate to be cut such as a substrate or a wafer, or may have an appropriate form such as a continuous sheet, or the sheet may be rolled into a tape shape.

The material of the base film 1 is not particularly limited, but it is preferable to use a material that transmits at least a part of energy rays of a predetermined level or more. Further, it is preferable to have flexibility that can endure expanding after dicing. The base film may not particularly have a cutting property with respect to cutting means such as a cutter used for cutting the adherend. For example, low-density polyethylene, linear polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypropylene, polybutene, polyolefin such as polymethylpentene, ethylene-acetic acid. Vinyl copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer,
Ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-
Polymers such as hexene copolymers, polyesters such as polyurethane and polyethylene terephthalate, polyimides, polyether ether ketones, polyvinyl chloride, polyvinylidene chloride, fluororesins, cellulosic resins and cross-linked products thereof can be mentioned. Further, the polymer may be used alone, or may be blended with several kinds as required, or may be used as a multilayer structure.

The thickness of the substrate film 1 can be appropriately selected within a range that does not impair operability and workability in each step such as sticking to a cut object, cutting of the cut object, peeling of cut pieces, and recovery. , Usually about 500 μm or less, preferably 3 to 3
The thickness is about 00 μm, more preferably about 5 to 250 μm. The base film 1 can be formed by a conventionally known film forming method. For example, a wet casting method, an inflation extrusion method, a T-die extrusion method or the like can be used. The base film 1 may be used without being stretched, or may be subjected to a uniaxial or biaxial stretching treatment as needed. In addition, the surface of the base material film 1 may be subjected to chemical or physical treatments such as chromic acid treatment, ozone exposure, flame exposure, high piezoelectric bombardment exposure, ionizing radiation treatment, and the like, if necessary.
A coating treatment with an undercoat (for example, an adhesive substance described below) may be applied.

The viscoelastic layer (A) is preferably one which can satisfy the above storage elastic modulus, and contains, for example, a composition of an organic viscoelastic body and an energy ray curable compound and / or an energy ray curable resin. It is formed by a cured product obtained by curing an energy ray-curable pressure-sensitive adhesive that is cured with energy rays.

Examples of the organic viscoelastic body include base polymers used for various pressure-sensitive adhesives such as acrylic and rubber. In particular, from the viewpoints of adhesiveness to semiconductor wafers, cleanability of the separated wafers with ultrapure water and appropriate organic solvents such as alcohol, and the like, the organic viscoelastic body is acrylic, which is a base polymer of an acrylic adhesive. Polymers are preferred.

Examples of the acrylic polymer include, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, t-butyl group, isobutyl group,
Amyl group, isoamyl group, hexyl 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,
Examples of the polymer include one or more components of (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 30 carbon atoms such as dodecyl group, and particularly having 4 to 18 carbon atoms. . In addition, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester, and (meth) of the present invention has the same meaning.

The acrylic polymer is used in order to improve cohesive strength, heat resistance, etc., if necessary, as described above.
It may contain units corresponding to other monomer components copolymerizable with the acrylic acid alkyl ester. Examples of such a monomer component include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid,
Carboxyl group-containing monomers such as fumaric acid and crotonic acid; acid anhydride monomers such as maleic anhydride and itaconic anhydride; 2-hydroxyethyl (meth) acrylate;
2-Hydroxypropyl (meth) acrylate, (meth)
4-hydroxybutyl acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4- Hydroxy group-containing monomers such as hydroxymethylcyclohexyl) methyl (meth) acrylate; styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid,
Sulfonic acid group-containing monomers such as (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; acrylamide, acrylonitrile, etc. can give. These copolymerizable monomer components may be used alone or in combination of two or more. The amount of these copolymerizable monomers used is preferably 50% by weight or less based on the total monomer components.

Further, the acrylic polymer may contain a polyfunctional monomer or the like as a monomer component for copolymerization, if necessary, for the purpose of crosslinking treatment. Examples of such polyfunctional monomers include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate
Acrylate, dipentaerythritol hexa (meth)
Examples thereof include acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate 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 of the total monomer components from the viewpoint of adhesive properties and the like.

The acrylic polymer may be of one type or of two types.
It is obtained by subjecting a mixture of one or more monomers to polymerization. The polymerization can be carried out by any method such as solution polymerization, emulsion polymerization, bulk polymerization and suspension polymerization. Viscoelastic layer (A)
From the standpoint of preventing contamination of semiconductor wafers and the like, it is preferable that the content of the low molecular weight substance is small. From this point, the weight average molecular weight of the acrylic polymer is preferably 300,000 or more, more preferably about 400,000 to 3,000,000.

Examples of the energy ray-curable compound to be blended with an organic viscoelastic body such as an acrylic polymer include:
Urethane oligomer, urethane (meth) acrylate,
Trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol Examples include hexa (meth) acrylate and 1,4-butanediol di (meth) acrylate. Examples of the energy ray-curable compound include various oligomers such as urethane-based, polyether-based, polyester-based, polycarbonate-based, and polybutadiene-based compounds, and those having a molecular weight of about 100 to 30,000 are suitable.

The amount of the energy ray-curable compound is, for example, 5 to 500 parts by weight, preferably 40 to 15 parts by weight, based on 100 parts by weight of the base polymer such as an acrylic polymer.
It is about 0 parts by weight.

As the energy ray-curable pressure-sensitive adhesive, an energy ray-curable resin having a carbon-carbon double bond as a base polymer in the side chain of the polymer or in the main chain or at the end of the main chain and having an adhesive property Those containing can be used without particular limitation. The energy ray-curable resin can be used alone, but the organic viscoelastic body and the energy ray-curable compound can be blended to the extent that the characteristics are not deteriorated.

The energy ray curable resin is preferably one having an acrylic polymer as a basic skeleton. Examples of the basic skeleton of the acrylic polymer include the acrylic polymers exemplified above.

The method of introducing the carbon-carbon double bond into the acrylic polymer is not particularly limited, and various methods can be adopted, but the molecular design is to introduce the carbon-carbon double bond into the side chain of the polymer. It's easy. For example, after previously copolymerizing a monomer having a functional group with an acrylic polymer,
Examples thereof include a method of subjecting a compound having a functional group capable of reacting with this functional group and a carbon-carbon double bond to a condensation or addition reaction while maintaining the radiation-curability of the carbon-carbon double bond. Examples of combinations of these functional groups include a carboxylic acid group and an epoxy group, a carboxylic acid group and an aziridyl group, and a hydroxyl group and an isocyanate group. Among these combinations of functional groups, the combination of a hydroxyl group and an isocyanate group is preferable because the reaction can be easily traced. In addition, the functional group may be on either side of the acrylic polymer and the compound, as long as the combination of these functional groups is a combination that produces the acrylic polymer having the carbon-carbon double bond. In the above preferable combination, it is preferable that the acrylic polymer has a hydroxyl group and the compound has an isocyanate group. In this case, examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate and the like. Also,
Examples of the acrylic polymer include the hydroxy group-containing monomer and 2-hydroxyethyl vinyl ether described above,
A copolymer of 4-hydroxybutyl vinyl ether, an ether compound of diethylene glycol monovinyl ether, or the like is used.

The energy ray-curable pressure-sensitive adhesive used for forming the viscoelastic layer (A) contains a photopolymerization initiator when the viscoelastic layer (A) is cured by ultraviolet rays or the like. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α′-dimethylacetophenone, 2-methyl-2-hydroxypropio. Phenon,
Α such as 1-hydroxycyclohexyl phenyl ketone
-Ketol compound; methoxyacetophenone, 2,2
-Dimethoxy-2-phenylacetophenone, 2,2-
Diethoxyacetophenone, 2-methyl-1- [4-
Acetophenone compounds such as (methylthio) -phenyl] -2-morpholinopropane-1; Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether;
Ketal compounds such as benzyl dimethyl ketal; 2
-Aromatic sulfonyl chloride compounds such as naphthalene sulfonyl chloride; Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; benzophenone, benzoylbenzoic acid, 3,3 Benzophenone compounds such as ′ -dimethyl-4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxane Son,
Thioxanthone compounds such as 2,4-diethylthioxanthone and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxides; acylphosphonates.

The photopolymerization initiator is blended in an amount of 0.1 parts by weight or more, and further 0.5 parts by weight, based on 100 parts by weight of the base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive, in consideration of reactivity. The above is preferable. If the amount is too large, the preservability of the pressure-sensitive adhesive tends to decrease.
It is preferably not more than 5 parts by weight, more preferably not more than 5 parts by weight.

The control of the viscoelastic layer (A) that can satisfy the storage elastic modulus is performed by using a base polymer having a high storage elastic modulus as the energy ray-curable pressure-sensitive adhesive, and adding a crosslinking agent to the base polymer. It can be performed by controlling the crosslink density of the layer (A). Examples of the cross-linking agent include polyfunctional isocyanate compounds, epoxy compounds, melamine compounds, metal salt compounds, metal chelate compounds, amino resin compounds, and peroxides. When using a cross-linking agent, the amount used is not particularly limited, depending on the balance with the base polymer to be cross-linked, further,
It is appropriately determined depending on the intended use as an adhesive. Generally, based on 100 parts by weight of the base polymer,
It is preferable to add about 0.1 to 5 parts by weight. The crosslinking density of the pressure-sensitive adhesive layer (A) can be controlled by appropriately adjusting the ratio of carbon-carbon double bonds contained in the energy ray-curable compound and the energy ray-curable resin exemplified above.

Further, the energy ray-curable pressure-sensitive adhesive for forming the viscoelastic layer (A) may optionally contain, in addition to the above-mentioned components, various conventionally known tackifiers, antioxidants, plasticizers, vulcanizates. You may use additives, such as an agent.

On the other hand, for forming the pressure-sensitive adhesive layer (B), various kinds of pressure-sensitive adhesives used for forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for dicing can be used. As the pressure-sensitive adhesive, for example, various pressure-sensitive adhesives such as the acrylic type and the rubber type mentioned above are used. In addition, the above-mentioned cross-linking agent and additives can be appropriately added to the pressure-sensitive adhesive. Further, the pressure-sensitive adhesive layer (B) can be an energy ray-curable type.
When the pressure-sensitive adhesive layer (B) is an energy ray-curable type,
Adhesive layer (B) by energy ray curing after dicing
It is possible to reduce the adhesiveness of the above, and it is possible to easily peel off the cut object from the adhesive sheet after dicing. As the energy ray-curable pressure-sensitive adhesive, the same energy ray-curable pressure-sensitive adhesive used for forming the viscoelastic layer (A) can be used.

The adhesive force of the pressure-sensitive adhesive layer (B) (in the case of an energy ray-curable pressure-sensitive adhesive, the adhesive force before irradiation with energy rays) is determined from the standpoints of wafer fixing / holding force and collectability of formed chips. Adhesive strength (90 degree peel value, peeling speed 30
0 mm / min) is 20 N / 20 mm or less, especially 0.00
1-10N / 20mm, and further 0.01-8N / 20
It is preferably mm.

The production of the pressure-sensitive adhesive sheet for dicing of the present invention is carried out, for example, by coating the base film 1 with an energy ray-curable pressure-sensitive adhesive and further irradiating it with energy rays such as ultraviolet rays and electron rays. After forming A), it can be formed by a method of applying a pressure-sensitive adhesive and heat-treating it to form the pressure-sensitive adhesive layer (B). Also,
Separately, a method of forming the pressure-sensitive adhesive layer (B) on the separator 2 and then laminating it on the viscoelastic layer (A) can be adopted.

Pressure-sensitive adhesive layer (B) of pressure-sensitive adhesive sheet for dicing
In terms of prevention of contamination during storage and distribution, it is preferable that the separator 2 covers and protects the semiconductor wafer before adhering to an object to be cut such as a semiconductor wafer. Examples of the constituent material of the separator 2 include paper, synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate. The surface of the separator 2 may be subjected to release treatment such as silicone treatment, long-chain alkyl treatment, and fluorine treatment, if necessary, in order to enhance the peelability from the pressure-sensitive adhesive layer (B). The thickness of the separator 2 is usually 10 to 200 μm, preferably about 25 to 100 μm.

Further, the adhesive sheet for dicing has an antistatic property for the purpose of preventing static electricity from being generated at the time of adhering to or peeling from the object to be cut and the circuit from being destroyed due to electrification of a semiconductor wafer or the like. It can also be given a noh. The antistatic ability can be imparted by various methods such as attaching a base film or a conductive layer composed of a charge transfer complex or a metal film, etc., and a method in which impurity ions that may alter the quality of a semiconductor wafer are less likely to be generated is preferable. .

The pressure-sensitive adhesive sheet for dicing of the present invention is subjected to dicing according to a conventional method by placing an object to be cut on the surface of the pressure-sensitive adhesive layer (B). In the dicing step, the blade is rotated at high speed to cut the object to be cut into a predetermined size. The cutting by dicing is up to the viscoelastic layer (A),
No cut is made up to the base film 1.

[0042]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples. The parts in each example are parts by weight.

Example 1 (Formation of viscoelastic layer (A)) 2,2'-azobisisobutyronitrile was mixed with 70 parts of methyl acrylate, 30 parts of butyl acrylate and 5 parts of acrylic acid to prepare a mixed monomer. Copolymerization in toluene in the presence of 1 part to give an acrylic polymer solution having a weight average molecular weight of 800,000. An energy ray-curable pressure-sensitive adhesive was prepared by adding 70 parts of a urethane oligomer, 5 parts of a polyfunctional isocyanate compound and 3 parts of an acetophenone photopolymerization initiator to 100 parts (solid content) of this acrylic copolymer polymer solution.

One side (treated side) of polyethylene terephthalate having a thickness of 50 μm was coated with the above energy ray-curable pressure-sensitive adhesive, and was left under a high pressure mercury lamp of 80 W / cm ² for 60 seconds to be treated with ultraviolet rays to give a thickness of 30 μm. Viscoelastic layer (A) was formed. The storage elastic modulus of the viscoelastic layer (A) at 23 ° C. was 3 × 10 ⁸ Pa. The storage elastic modulus is a measured value at a frequency of 1 Hz using a viscoelastic spectrometer (torsion method) manufactured by Rheometrics.

(Formation of Adhesive Layer (B): Preparation of Adhesive Tape for Dicing) A mixed monomer consisting of 100 parts of n-butyl acrylate and 5 parts of acrylic acid was mixed with 2,2'-azobisisobutyronitrile 0 Copolymerization in toluene in the presence of 1 part to give a solution containing an acrylic copolymer having a weight average molecular weight of 800,000. An acrylic pressure-sensitive adhesive was prepared by adding 5 parts of a polyfunctional isocyanate compound to 100 parts (solid content) of this acrylic copolymer polymer solution.

The acrylic adhesive is applied onto the viscoelastic layer (A) and heated at 130 ° C. for 3 minutes to give a thickness of 5 μm.
A pressure-sensitive adhesive layer (B) of m was formed to prepare a pressure-sensitive adhesive sheet for dicing.

Example 2 (Formation of the viscoelastic layer (A)) A mixed monomer consisting of 90 parts of butyl acrylate, 5 parts of acrylonitrile and 5 parts of acrylic acid was mixed with 2,2'-azobisisobutyronitrile (0.2 part).
Copolymerization in toluene in the presence of 1 part to obtain an acrylic polymer solution having a weight average molecular weight of 600,000. An energy ray-curable pressure-sensitive adhesive was prepared by adding 50 parts of a urethane oligomer, 5 parts of a polyfunctional isocyanate compound and 5 parts of an acetophenone photopolymerization initiator to 100 parts (solid content) of the acrylic copolymer solution.

On one side (treated side) of a high-density polyethylene film having a thickness of 70 μm, the above-mentioned energy ray-curable pressure-sensitive adhesive was applied, and it was left under a high pressure mercury lamp of 80 W / cm ² for 60 seconds to be treated with ultraviolet rays to obtain a thickness. A viscoelastic layer (A) having a thickness of 30 μm was formed. The storage elastic modulus of the viscoelastic layer (A) at 23 ° C. was 4 × 10 ⁷ Pa.

(Formation of pressure-sensitive adhesive layer (B): preparation of pressure-sensitive adhesive tape for dicing) The same acrylic pressure-sensitive adhesive as in Example 1 was coated on the viscoelastic layer (A), and the pressure-sensitive adhesive layer was dried at 130 ° C. for 3 minutes. By heating, a pressure-sensitive adhesive layer (B) having a thickness of 5 μm was formed to produce a pressure-sensitive adhesive sheet for dicing.

Example 3 (Formation of viscoelastic layer (A)) A mixed monomer consisting of 90 parts of butyl acrylate, 5 parts of acrylonitrile and 5 parts of acrylic acid was mixed with 2,2'-azobisisobutyronitrile (0.1 part).
Copolymerization in toluene was carried out in the presence of 1 part to obtain an acrylic polymer solution having a weight average molecular weight of 500,000. An energy ray-curable pressure-sensitive adhesive was prepared by adding 10 parts of a polyfunctional acrylic monomer, 5 parts of a polyfunctional isocyanate compound and 10 parts of an acetophenone photopolymerization initiator to 100 parts (solid content) of the acrylic copolymer solution. .

One side (treated surface) of soft polyvinyl chloride having a thickness of 110 μm was coated with the above-mentioned energy ray-curable pressure-sensitive adhesive, and was left under a high pressure mercury lamp of 80 W / cm ² for 60 seconds to be treated with ultraviolet rays. A viscoelastic layer (A) having a thickness of 30 μm was formed. Storage elastic modulus of the viscoelastic layer (A) at 23 ° C. is 5 ×
It was 10 ⁹ Pa.

(Formation of pressure-sensitive adhesive layer (B): preparation of pressure-sensitive adhesive tape for dicing) 2,2'-azobisisobutyrate was mixed with a mixed monomer consisting of 70 parts of methyl acrylate, 30 parts of butyl acrylate and 5 parts of acrylic acid. Copolymerization was carried out in toluene in the presence of 0.1 part of ronitrile to obtain an acrylic copolymer having a weight average molecular weight of 800,000. An energy ray-curable pressure-sensitive adhesive was prepared by adding 70 parts of a urethane oligomer, 5 parts of a polyfunctional isocyanate compound, and 5 parts of an acetophenone photopolymerization initiator to 100 parts (solid content) of the acrylic copolymer solution.

On the viscoelastic layer (A), the energy ray-curable pressure-sensitive adhesive is applied and heated at 130 ° C. for 3 minutes,
A pressure-sensitive adhesive layer (B) having a thickness of 5 μm was formed to prepare a pressure-sensitive adhesive sheet for dicing.

Example 4 (Formation of viscoelastic layer (A)) A mixed monomer consisting of 90 parts of butyl acrylate, 5 parts of acrylonitrile and 5 parts of acrylic acid was mixed with 2,2'-azobisisobutyronitrile (0.1 part).
Copolymerization in toluene was carried out in the presence of 1 part to obtain an acrylic polymer solution having a weight average molecular weight of 500,000. An energy ray-curable pressure-sensitive adhesive was prepared by adding 10 parts of a polyfunctional acrylic monomer, 5 parts of a polyfunctional isocyanate compound and 5 parts of an acetophenone photopolymerization initiator to 100 parts (solid content) of the acrylic copolymer solution. .

One side (treated side) of a high-density polyethylene film having a thickness of 70 μm was coated with the above-mentioned energy ray-curable pressure-sensitive adhesive and left under a high pressure mercury lamp of 80 W / cm ² for 60 seconds to be treated with ultraviolet rays to obtain a thick layer. A viscoelastic layer (A) having a thickness of 30 μm was formed. The storage elastic modulus of the viscoelastic layer (A) at 23 ° C. was 8 × 10 ⁸ Pa.

(Formation of adhesive layer (B): Preparation of adhesive tape for dicing) 2,2'-azo was used as a mixed monomer consisting of 50 parts of ethyl acrylate, 50 parts of butyl acrylate and 16 parts of 2-hydroxyethyl acrylate. By copolymerization in toluene in the presence of 0.1 part of bisisobutyronitrile, an acrylic copolymer having a weight average molecular weight of 500,000 was obtained. Then, for this acrylic copolymer,
20 parts of 2-methacryloyloxyethyl isocyanate was subjected to an addition reaction to introduce a carbon-carbon double bond into the inner chain of the polymer molecule. An energy ray-curable pressure-sensitive adhesive was prepared by further adding 1 part of a polyfunctional isocyanate compound and 3 parts of an acetophenone photopolymerization initiator to 100 parts by weight (solid content) of this polymer.

On the viscoelastic layer (A), the energy ray-curable pressure-sensitive adhesive was applied and heated at 130 ° C. for 3 minutes,
A pressure-sensitive adhesive layer (B) having a thickness of 5 μm was formed to prepare a pressure-sensitive adhesive sheet for dicing.

Comparative Example 1 A pressure-sensitive adhesive sheet for dicing was produced in the same manner as in Example 1 except that the viscoelastic layer (A) was not formed.

Comparative Example 2 A pressure-sensitive adhesive sheet for dicing was produced in the same manner as in Example 2 except that the viscoelastic layer (A) was not formed.

Comparative Example 3 An adhesive sheet for dicing was produced in the same manner as in Example 3 except that the viscoelastic layer (A) was not formed.

(Evaluation test) The pressure-sensitive adhesive sheets for dicing obtained in Examples and Comparative Examples were evaluated by the following methods.
The results are shown in Table 1.

A 4-inch diameter semiconductor wafer having a circuit pattern formed thereon was subjected to a back surface polishing treatment to a thickness of 0.15 mm, and the adhesive sheet for dicing obtained in each of Examples and Comparative Examples was bonded and fixed. Using a dicing device (Disco, DFD-651), dicing speed 10
0 mm / sec, dicing blade (manufactured by DISCO, 20
50 HFDD) at a rotation speed of 40,000 rpm, full cutting was performed under the condition that the cutting depth of the pressure-sensitive adhesive sheet for dicing was 30 μm, and cut into 3 mm × 3 mm chips.

(Chipping) After dicing, 1000 arbitrary semiconductor chips (cut objects) were picked up (peeled) and the chipping on the side surface of the semiconductor chip was observed.
The observed ratio of 0.075 mm triangle chipping was regarded as defective, and the ratio was calculated.

[0064]

[Table 1] From Table 1, as in Examples, by using the pressure-sensitive adhesive sheet for dicing in which the viscoelastic layer (A) and the pressure-sensitive adhesive layer (B) were laminated, the cutting depth of dicing was limited to the viscoelastic layer (A). It is recognized that the occurrence of chipping can be suppressed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a pressure-sensitive adhesive sheet for dicing.

[Explanation of symbols]

1: Base film A: Viscoelastic layer (A) B: Adhesive layer (B) 2: Separator

Claims (6)

[Claims] 1. A viscoelastic layer (A) cured by energy rays from the side of the base film, and then an adhesive layer (B) are laminated in this order on at least one side of the base film. Adhesive sheet for dicing. 2. An energy ray-curable pressure-sensitive adhesive, wherein the energy ray-cured viscoelastic layer (A) contains a composition of an organic viscoelastic body and an energy ray-curable compound and / or an energy ray-curable resin. The pressure-sensitive adhesive sheet for dicing according to claim 1, which is a cured product of the above. 3. A storage elastic modulus at 23 ° C. of the viscoelastic layer (A) cured by energy rays is 1 × 10 ⁷ to 1 ×.
The pressure-sensitive adhesive sheet for dicing according to claim 1, which is in a range of 10 ¹⁰ Pa. 4. The pressure-sensitive adhesive sheet for dicing according to claim 1, wherein the viscoelastic layer (A) cured by energy rays has a thickness of 5 to 300 μm. 5. The energy ray-cured viscoelastic layer (A) has a thickness equal to or greater than the thickness of the pressure-sensitive adhesive layer (B). Adhesive sheet for dicing. 6. The dicing is performed when a body to be cut is placed on the surface of the pressure-sensitive adhesive layer (B) of the pressure-sensitive adhesive sheet for dicing according to claim 1 and the body to be cut is diced. A method for producing a cut piece, wherein the cut to the pressure-sensitive adhesive sheet for dicing is up to the viscoelastic layer (A) and the base film is not cut.