JP3209544B2 - Adhesive sheet for attaching wafer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet for attaching a wafer, and more particularly, to a pressure-sensitive adhesive sheet for attaching a wafer which is used for cutting and separating a semiconductor wafer into small pieces.

[0002]

BACKGROUND OF THE INVENTION Semiconductor wafers of silicon, gallium arsenide and the like are manufactured in a large diameter state, and this wafer is cut and separated (diced) into element pieces and then transferred to the next step, a mounting step. . At this time, each step of dicing, washing, drying, expanding, pickup, and mounting is added to the semiconductor wafer in a state of being pasted on the adhesive sheet in advance.

[0003] Such an adhesive sheet used in the steps from the dicing step to the pick-up step of a semiconductor wafer has a sufficient adhesive force to the wafer chip from the dicing step to the drying step, and the wafer is picked up during the pick-up. It is desired that the chip has such an adhesive strength that an adhesive does not adhere to the chip.

[0004] Such an adhesive sheet is disclosed in
0-196,956 and JP-A-60-223,
No. 139, a pressure-sensitive adhesive sheet coated with a pressure-sensitive adhesive comprising a low molecular weight compound having at least two or more photopolymerizable carbon-carbon double bonds in a molecule, which can be three-dimensionally reticulated by light irradiation, on a substrate surface. Proposed. These proposals are pressure-sensitive adhesive tapes in which a radiation-curable pressure-sensitive adhesive is applied on a radiation-transparent substrate, and the radiation-curable compound contained in the pressure-sensitive adhesive is cured by irradiation with radiation to form a three-dimensional net-like adhesive. It is based on the principle that a fluidized structure is provided to significantly reduce its fluidity.

[0005] The conventional pressure-sensitive adhesive sheet as exemplified above has the following problems, particularly in the expanding step. The expanding step is a step of widening the interval between the diced element pieces (chips) and facilitating chip pickup. When the conventional adhesive sheet for attaching a wafer is used, there is a difference between an extension rate (expansion rate) of a portion where the wafer is attached and an extension rate of a portion where the wafer is not attached. It was difficult to get the spacing. That is, since the expansion rate of the portion where the wafer is attached is smaller than the expansion rate of the portion where the wafer is not attached, in the expanding step, the portion where the wafer is not attached is preferentially extended. And
The portion to which the wafer was attached did not extend much, and it was necessary to expand excessively in order to obtain a sufficient chip interval. In addition, due to the above-mentioned problems, the substrate used may be limited.

In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. 2-265258 discloses that an adhesive is applied only to a surface portion of a base material to which a wafer is to be adhered, and only to that portion. A dicing apparatus capable of performing ultraviolet irradiation is disclosed. However, this method has a large number of steps and its effect is not sufficient.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has a difference between an expansion ratio of a portion to which a wafer is attached and an expansion ratio of a portion to which no wafer is attached. It is an object of the present invention to solve the above problem in the expanding step caused by the above. Another object of the present invention is to increase the material margin of the base material by solving the above problems.

[0008]

SUMMARY OF THE INVENTION An adhesive sheet for attaching a wafer according to the present invention comprises a substrate and an adhesive layer, and has at least one surface of the substrate having substantially the same planar shape as the wafer to be attached. A radiation attenuation layer is formed , and the pressure-sensitive adhesive layer contains a pressure-sensitive adhesive and a radiation-polymerizable compound. And in this invention, it is preferable that the radiation transmittance of the said radiation attenuation layer is 1-90%.

[0009]

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, FIG. 2 or FIG. 3, a pressure-sensitive adhesive sheet 1 for attaching a wafer according to the present invention has a substrate 2, a pressure-sensitive adhesive layer 3, and a radiation attenuator. And a layer 4. Whether the radiation attenuation layer 4 is formed between the substrate 2 and the pressure-sensitive adhesive layer 3 (FIG. 1), or is formed on the surface of the substrate 2 opposite to the pressure-sensitive adhesive layer 3 (FIG. 2). ,
Alternatively, it is formed on both surfaces of the substrate 2 (not shown). Before use, in order to protect the pressure-sensitive adhesive layer 3, it is preferable to temporarily adhere a peelable sheet 5 to the upper surface of the pressure-sensitive adhesive layer 3 as shown in FIG.

[0010] The shape of the pressure-sensitive adhesive sheet according to the present invention can take any shape such as a tape shape and a label shape. Hereinafter, the substrate 2, the pressure-sensitive adhesive layer 3, and the radiation attenuating layer 4 used in the present invention will be sequentially described.

As the substrate 2, a substrate having radiation transparency is used. Various types of such base materials have been conventionally known. For example, when using ultraviolet rays as radiation, polyester, polyethylene,
Polypropylene, polybutene, polybutadiene, vinyl chloride, vinyl chloride copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth)
Examples of the base material include resin base materials such as an acrylate copolymer, polystyrene, and polycarbonate, and base materials obtained by applying a silicone resin or the like to the surface of these resin base materials and subjecting them to release treatment. When an electron beam is used as the radiation, a fluororesin or a colored opaque film is used. Further, for the purpose of the present invention,
It is preferable to use a substrate having a Young's modulus of about 0 ² to 10 ⁴ Kg / cm ² .

As the substrate 2, one of the above-mentioned resin films may be used alone, or a laminated film formed by laminating two or more types may be used. The thickness of the substrate as described above is usually 10 to 300 μm, preferably 50 to 300 μm.
１５０150 μm.

In the pressure-sensitive adhesive sheet of the present invention, as will be described later, the electron beam (EB) or ultraviolet (U)
The substrate 2 is not required to be transparent in the case of EB irradiation, but needs to be transparent in the case of UV irradiation.

As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 3, conventionally known pressure-sensitive adhesives can be widely used, but acrylic pressure-sensitive adhesives are preferred. A copolymer with an acrylic polymer selected from a polymer and a copolymer and other functional monomers, and a mixture of these polymers are used. For example, acrylates include ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, and the like. Can be preferably used.

Further, in order to enhance the compatibility with the oligomer described later, a monomer such as acrylic acid or methacrylic acid, acrylonitrile, vinyl acetate, etc. may be copolymerized. The molecular weight of the acrylic polymer obtained by polymerizing these monomers is 2.0 × 10 ^{5 to} 10.0 × 10 ⁵ , preferably 4.0 × 10 ^{5 to} 8.0 × 10 ⁵ . is there.

By including a radiation polymerizable compound in the pressure-sensitive adhesive layer as described above, the adhesive force can be reduced by irradiating the pressure-sensitive adhesive layer with radiation after cutting and separating the wafer. Examples of such a radiation polymerizable compound include, for example, JP-A-60-196,956.
Low molecular weight compounds having at least two or more photopolymerizable carbon-carbon double bonds in a molecule which can be three-dimensionally reticulated by light irradiation as disclosed in JP-A No. 60-223139 and JP-A-60-223139. Widely used, specifically,
Trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or 1,4-butylene glycol diacrylate, 1,6-hexane Diol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate and the like are used.

Further, as the radiation polymerizable compound, a urethane acrylate oligomer can be used in addition to the acrylate compound described above. The urethane acrylate oligomer includes a polyol compound such as a polyester type or a polyether type, and a polyvalent isocyanate compound such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4 -Acrylate or methacrylate having a hydroxyl group, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, on a terminal isocyanate urethane prepolymer obtained by reacting xylylene diisocyanate, diphenylmethane 4,4-diisocyanate or the like. , 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate Obtained by. This urethane acrylate oligomer is a radiation polymerizable compound having at least one carbon-carbon double bond.

Such a urethane acrylate oligomer has a molecular weight of, particularly, 3000 to 30,000, preferably 3000 to 10,000, and more preferably 400 to 10,000.
It is preferable to use a value of 0 to 8000 because even when the surface of the semiconductor wafer is rough, the adhesive does not adhere to the chip surface when the wafer chip is picked up. When a urethane acrylate oligomer is used as the radiation polymerizable compound, Japanese Patent Application Laid-Open No.
As compared with the case of using a low-molecular-weight compound having at least two photopolymerizable carbon-carbon double bonds in the molecule as disclosed in JP-A No. 6-2006, an extremely excellent pressure-sensitive adhesive sheet is obtained. That is, the adhesive force of the pressure-sensitive adhesive sheet before the irradiation is sufficiently large, and the adhesive force is sufficiently reduced after the radiation irradiation, so that the pressure-sensitive adhesive does not remain on the chip surface when the wafer chip is picked up.

The mixing ratio of the acrylic pressure-sensitive adhesive and the urethane acrylate oligomer in the pressure-sensitive adhesive of the present invention is such that the urethane acrylate oligomer is used in an amount of 50 to 900 parts by weight with respect to 100 parts by weight of the acrylic pressure-sensitive adhesive. Preferably. In this case, the resulting pressure-sensitive adhesive sheet has a large initial adhesive strength, and the adhesive strength is significantly reduced after irradiation, so that wafer chips can be easily picked up from the pressure-sensitive adhesive sheet.

If necessary, the pressure-sensitive adhesive layer 3 may contain, in addition to the above-mentioned pressure-sensitive adhesive and a radiation-polymerizable compound, a compound which is colored by irradiation with radiation. By including a compound to be colored in the pressure-sensitive adhesive 3 by such radiation irradiation, after the pressure-sensitive adhesive sheet is irradiated with radiation, the sheet is colored, and thus the detection accuracy when detecting a wafer chip by an optical sensor is improved. As a result, malfunction does not occur when picking up a wafer chip. In addition, an effect is obtained that it is immediately possible to visually determine whether or not radiation has been applied to the adhesive sheet.

The compound that is colored by irradiation with radiation is a compound that is colorless or pale before irradiation with radiation, but is a compound that becomes colored by irradiation with radiation. A preferred specific example of this compound is a leuco dye. As the leuco dye, commonly used triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based and spiropyran-based dyes are preferably used. Specifically, 3- [N-
(P-tolylamino)]-7-anilinofluoran, 3
-[N- (p-tolyl) -N-methylamino] -7-anilinofluoran, 3- [N- (p-tolyl) -N-ethylamino] -7-anilinofluoran, 3-diethylamino -6-methyl-7-anilinofluoran, crystal violet lactone, 4,4 ', 4 "-trisdimethylaminotriphenylmethanol, 4,4', 4"
-Trisdimethylaminotriphenylmethane and the like.

Examples of the developer preferably used together with these leuco dyes include conventionally used electron acceptors such as a phenol formalin resin initial polymer, an aromatic carboxylic acid derivative, and activated clay. In the case where is changed, various known color formers can be used in combination.

Such a compound which is colored by irradiation with radiation may be once dissolved in an organic solvent or the like and then included in the adhesive layer, or may be finely powdered and included in the adhesive layer. . This compound is present in the pressure-sensitive adhesive layer in an amount of 0.01 to
It is desirable to use it in an amount of 10% by weight, preferably 0.5 to 5% by weight. When the compound is used in an amount exceeding 10% by weight, the radiation applied to the pressure-sensitive adhesive sheet is excessively absorbed by the compound, and thus the curing of the pressure-sensitive adhesive layer may be insufficient. When used in an amount of less than 0.01% by weight, the pressure-sensitive adhesive sheet may not be sufficiently colored when irradiated with radiation, and malfunction may easily occur when picking up a wafer chip.

In some cases, the light-scattering inorganic compound powder may be contained in the pressure-sensitive adhesive layer 3 in addition to the pressure-sensitive adhesive and the radiation-polymerizable compound as described above. By including such a light-scattering inorganic compound powder in the pressure-sensitive adhesive layer 3, even if the surface of an adherend such as a semiconductor wafer becomes gray or black for some reason, the pressure-sensitive adhesive sheet is irradiated with radiation such as ultraviolet rays. Then, even in the grayed or blackened part, the adhesive strength is sufficiently reduced,
Therefore, there is obtained an effect that the adhesive does not adhere to the surface of the wafer chip when the wafer chip is picked up, and that the adhesive has sufficient adhesive strength before the irradiation of the radiation.

This light-scattering inorganic compound is formed of an ultraviolet (U)
V) or a compound capable of irregularly reflecting radiation when irradiated with radiation such as electron beam (EB), specifically, silica powder, alumina powder, silica-alumina powder, mica powder And the like. The light-scattering inorganic compound preferably reflects the above-described radiation almost completely, but of course, a compound that absorbs the radiation to some extent can also be used.

The light-scattering inorganic compound is preferably in the form of a powder, and has a particle size of 1 to 100 μm, preferably 1 to 100 μm.
It is desirable that it is about 20 μm. The light-scattering inorganic compound is used in an amount of 0.1 to 10% by weight, preferably 1 to 4% by weight in the pressure-sensitive adhesive layer. When the compound is used in an amount exceeding 10% by weight in the pressure-sensitive adhesive layer,
The adhesive strength of the pressure-sensitive adhesive layer may be reduced. On the other hand, if the content is less than 0.1% by weight, even if the surface of the semiconductor wafer is grayed or blackened, even if the part is irradiated with radiation, the adhesive strength is reduced. May not be sufficiently reduced and the adhesive may remain on the wafer surface during pickup.

The pressure-sensitive adhesive sheet obtained by adding the light-scattering inorganic compound powder to the pressure-sensitive adhesive layer can be used even when the semiconductor wafer surface is grayed or blacked for some reason. It is considered that the reason why the radiation force is applied to the converted portion to sufficiently reduce the adhesive force also in this portion is as follows. That is, the pressure-sensitive adhesive sheet 1 according to the present invention has the pressure-sensitive adhesive layer 3, and when the pressure-sensitive adhesive layer 3 is irradiated with radiation, the radiation-polymerizable compound contained in the pressure-sensitive adhesive layer 3 is cured to form the adhesive. The power will be reduced. However, a grayed or blackened portion may occur on the semiconductor wafer surface for some reason. In such a case, when the adhesive layer 3 is irradiated with radiation, the radiation is applied to the adhesive layer 3.
Passes through to reach the wafer surface, but if there is a gray or black portion on the wafer surface, the radiation is absorbed at this portion and will not be reflected. For this reason, the radiation which should be used for curing the pressure-sensitive adhesive layer 3 is absorbed in the grayed or blackened portions, and the curing of the pressure-sensitive adhesive layer 3 becomes insufficient, and the adhesive strength is not sufficiently reduced. become. Therefore, it is considered that the adhesive will adhere to the chip surface when the wafer chip is picked up.

However, when the light-scattering inorganic compound powder is added to the pressure-sensitive adhesive layer 3, the irradiated radiation collides with the compound before reaching the wafer surface and changes its direction. Therefore, even if there is a grayed or blackened part on the wafer chip surface, the diffusely reflected radiation penetrates well into the area above this part, and therefore, the grayed or blackened part is also hardened sufficiently. I do. For this reason,
By adding the light-scattering inorganic compound powder into the pressure-sensitive adhesive layer, even if there is a grayed or blackened portion on the semiconductor wafer surface for some reason, the pressure-sensitive adhesive layer is insufficiently cured at this portion. Therefore, the adhesive does not adhere to the chip surface when picking up the wafer chip.

Further, in the present invention, abrasive grains may be dispersed in the base material. This abrasive has a particle size of 0.5 to 100 μm.
m, preferably 1 to 50 μm, and a Mohs hardness of 6
-10, preferably 7-10. Specifically, green carborundum, artificial corundum, optical emery, white alundum, boron carbide, chromium oxide
(III), cerium oxide, diamond powder and the like are used. Such abrasive grains are preferably colorless or white. Such abrasive grains are contained in the base material 2 in an amount of 0.5 to
It is present in an amount of 70% by weight, preferably 5 to 50% by weight. Such abrasive grains are particularly preferably used when the cutting blade is used at a depth that cuts not only into the wafer but also into the base material 2.

By including the abrasive grains in the base material as described above, the cutting blade cuts into the base material, and even if the adhesive is adhered to the cutting blade, the clogging is easily performed by the polishing effect of the abrasive grains. Can be removed.

By mixing an isocyanate-based curing agent into the above-mentioned pressure-sensitive adhesive, the initial adhesive strength can be set to an arbitrary value. As such a curing agent,
Specifically, a polyvalent isocyanate compound such as 2,4
-Tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate,
1,4-xylene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-
2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, lysine isocyanate and the like are used.

Further, in the case of UV irradiation in the above-mentioned pressure-sensitive adhesive, by mixing a UV initiator, the polymerization curing time by UV irradiation and the amount of UV irradiation can be reduced.

Specific examples of such a UV initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone and the like can be mentioned.

The radiation attenuation layer 4 is formed between the base material 2 and the pressure-sensitive adhesive layer 3, formed on the surface of the base material 2 opposite to the pressure-sensitive adhesive layer 3, or 2 are formed on both surfaces. The radiation attenuating layer 4 has substantially the same shape as the wafer attached to the pressure-sensitive adhesive sheet of the present invention.

The radiation attenuating layer 4 contains a compound having a function of reflecting or absorbing radiation and attenuating the amount of transmitted radiation (hereinafter sometimes referred to as a radiation attenuating compound). Layer. As such a radiation attenuating compound, various compounds can be used without any particular limitation. In the present invention, particularly preferably used radiation attenuating compounds are ultraviolet absorbing compounds such as benzophenone compounds, benzotriazole compounds, salylate compounds, cyanoacrylate compounds; azo pigments, phthalocyanine pigments, and anthraquinone, perylene And organic compounds such as lead, lead hydroxide, barium, barium hydroxide, and barium stearate, which have an electron beam shielding effect, and the like. These are used alone or in combination of two or more.

Such a radiation attenuating compound is used by dissolving or dispersing it in a suitable binder agent, and is applied or printed on a substrate in accordance with the shape of a wafer to be attached to an adhesive sheet to form a radiation attenuating layer. Is done.

The thickness of the radiation-attenuating layer depends on the radiation-attenuating compound contained in the radiation-attenuating layer, and cannot be said to be any more, but is generally about 0.5 to 20 μm, preferably about 1.0 to 8 μm. It is.

The radiation transmittance of such a radiation attenuation layer is from 1 to 90%, preferably from 5 to 60%,
Particularly preferably, it is 5 to 30%. The radiation attenuating layer has a Young's modulus of 1 × 10 ^{2 to} 5 × 10 ⁴ Kg / cm ² , preferably 5 × 10 ² to 1 × 10 ⁴ Kg / cm ² , and particularly preferably 1 × 10 ^{3 to} 5 ×. It is about 10 ³ Kg / cm ² and does not affect the elongation of the substrate and the pressure-sensitive adhesive layer in the expanding step.

The pressure-sensitive adhesive sheet for attaching a wafer according to the present invention comprises:
It is composed of the base material 2, the pressure-sensitive adhesive layer 3 and the radiation attenuation layer 4. When radiation is irradiated from the substrate side of the pressure-sensitive adhesive sheet for attaching a wafer having such a configuration, a portion of the pressure-sensitive adhesive layer 3 that is covered with the radiation attenuation layer 4 (hereinafter, may be referred to as a radiation attenuation portion). The amount of radiation to be applied is attenuated, and a large amount of radiation is applied to other portions (hereinafter, sometimes referred to as non-radiation attenuated portions) other than the portion. As a result, the pressure-sensitive adhesive layer in the non-radiation attenuating portion is sufficiently cured, and the expansion rate in the expanding step is reduced. In addition, since the pressure-sensitive adhesive layer of the radiation attenuating portion does not sufficiently cure, the expansion ratio in the expanding step does not decrease much. Although the pressure-sensitive adhesive layer of the radiation attenuating portion does not sufficiently cure, the adhesive force is sufficiently low to pick up the wafer.

Since the expansion rate of the pressure-sensitive adhesive layer in the non-radiation attenuating portion is low and the expansion rate in the pressure-sensitive adhesive layer in the radiation attenuating portion does not decrease so much, even if the expansion is performed, only the pressure-sensitive adhesive layer in the non-radiation attenuating portion Is not preferentially expanded, and it becomes easy to obtain a desired chip interval.

In order to protect the pressure-sensitive adhesive layer 3 before using the pressure-sensitive adhesive sheet for attaching a wafer according to the present invention, as shown in FIG. It is preferable to keep it. As the releasable sheet 5, a conventionally known sheet is used without any particular limitation.

Hereinafter, a method for using the pressure-sensitive adhesive sheet according to the present invention will be described. When the peelable sheet 5 is provided on the upper surface of the pressure-sensitive adhesive sheet 1 according to the present invention, the sheet 5 is removed, and then the pressure-sensitive adhesive sheet 3 is placed with the pressure-sensitive adhesive layer 3 facing upward. As shown, a semiconductor wafer A to be diced on the upper surface of the pressure-sensitive adhesive layer 3 is attached above a portion where the radiation attenuation layer 4 is formed. Various processes of dicing, cleaning, and drying are added to the wafer A in this state of attachment. At this time, the wafer chips are sufficiently adhered and held on the pressure-sensitive adhesive sheet by the pressure-sensitive adhesive layer 3, so that the wafer chips do not fall off during the respective steps.

Next, each wafer chip is picked up from the adhesive sheet and mounted on a predetermined base.
At this time, prior to or at the time of pickup, as shown in FIG. 7, radiation B such as ultraviolet rays (UV) or electron beams (EB) is irradiated onto the pressure-sensitive adhesive layer 3 of the pressure-sensitive adhesive sheet 1 so that the pressure-sensitive adhesive layer 3 The radiation polymerizable compound contained therein is polymerized and cured. When the radiation polymerizable compound is polymerized and cured by irradiating the pressure-sensitive adhesive layer 3 with radiation in this manner,
The adhesive strength of the portion where the wafer is stuck (radiation attenuating portion) decreases to such an extent that the wafer can be picked up, but the expansion rate does not decrease much. On the other hand, since a large amount of radiation is irradiated to a portion where the wafer is not attached (non-radiation attenuated portion), curing proceeds sufficiently and the expansion rate is significantly reduced. As a result, in the expanding step, only the portion where the wafer is not attached is not preferentially extended, and the portion where the wafer is attached is also extended, so that a desired chip interval can be obtained. It will be easier.

The irradiation of the pressure-sensitive adhesive sheet 1 is performed from the surface of the substrate 2 on which the pressure-sensitive adhesive layer 3 is not provided. Therefore, as described above, when UV is used as the radiation, the substrate 2 needs to be light-transmitting, but when EB is used as the radiation, the substrate 2 does not necessarily need to be light-transmitting. Absent.

After the expanding step, as shown in FIG. 8, the chips A ₁ , A ₂ ... A to be picked up from the lower surface of the base material 2 by the needle rod 6 according to a conventional method.
₅ are picked up, and the chips A ₁ ... Are picked up by, for example, a suction collet 7 and mounted on a predetermined base. Thus, the wafer chips A ₁ , A ₂
By picking up the chips, you can easily pick up the chips because there is sufficient chip spacing, and the adhesion is sufficiently reduced, so that good quality chips without contamination can be obtained. Can be

[0046]

As described above, according to the pressure-sensitive adhesive sheet for attaching a wafer according to the present invention, a desired chip interval can be easily obtained in the expanding step, and excessive expanding is not required. .

[0047]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0048]

Example 1 A soft vinyl chloride film (containing 30% of a plasticizer, a thickness of 80 μm) was used as a base material.
An acrylic resin containing 3 parts by weight of 4-dihydroxybenzophenone was printed on a 5-inch wafer by screen printing. Acrylic polymer (copolymer of n-butyl acrylate and acrylic acid) as adhesive
A composition comprising 100 parts by weight, 100 parts by weight of a urethane acrylate oligomer having a molecular weight of 8000, and 10 parts by weight of a curing agent (aromatic diisocyanate) is treated with a silicone-treated polyethylene terephthalate film (3
8 μm) to form a pressure-sensitive adhesive tape bonded to the above substrate.

After sticking a 5-inch wafer to the printing section on this adhesive tape, it was mounted on a flat frame and
Full-cut into 5 mm square chips with a thick diamond blade. Thereafter, ultraviolet light having an illuminance of 200 mW / cm ² was irradiated from the surface on the substrate side for 2 seconds.

Next, the dicing tape was expanded by 15% using an expanding jig. Table 1 shows the expansion ratio of the portion where the wafer was attached.

[0051]

Example 2 Example 1 was repeated except that a monoazo dye was used instead of 2,4-dihydroxybenzophenone. Table 1 shows the expansion ratio of the portion where the wafer was attached.

[0052]

Comparative Example 1 The same operation as in Example 1 was performed except that no printing layer was provided. Table 1 shows the expansion ratio of the portion where the wafer was attached.

[0053]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a sectional view of a pressure-sensitive adhesive sheet according to the present invention.

FIG. 2 is a cross-sectional view of the pressure-sensitive adhesive sheet according to the present invention.

FIG. 3 is a cross-sectional view of the pressure-sensitive adhesive sheet according to the present invention.

FIG. 4 is a perspective view of the pressure-sensitive adhesive sheet according to the present invention as viewed from a substrate surface.

FIG. 5 is an explanatory diagram in a case where the pressure-sensitive adhesive sheet according to the present invention is used from a dicing step to a pickup step of a semiconductor wafer.

FIG. 6 is an explanatory view in a case where the pressure-sensitive adhesive sheet according to the present invention is used from a dicing step to a pickup step of a semiconductor wafer.

FIG. 7 is an explanatory diagram in the case where the pressure-sensitive adhesive sheet according to the present invention is used from a dicing step to a pickup step of a semiconductor wafer.

FIG. 8 is an explanatory diagram in a case where the pressure-sensitive adhesive sheet according to the present invention is used from a dicing step to a pickup step of a semiconductor wafer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Adhesive sheet 2 ... Base material 3 ... Adhesive layer 4 ... Radiation attenuation layer 5 ... Releasable sheet 6 ... Push-up needle rod 7 ... Suction collet A ... Wafer B ... Radiation

Continuation of front page (56) References JP-A-2-265258 (JP, A) JP-A-3-66772 (JP, A) JP-A-61-276232 (JP, A) JP-A-60-223139 (JP) JP-A-60-196956 (JP, A) JP-A-4-233249 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/301

Claims (2)

(57) [Claims] 1. A pressure-sensitive adhesive sheet for attaching a wafer, comprising a substrate and an adhesive layer, wherein a radiation attenuating layer having substantially the same planar shape as the wafer to be attached is provided on at least one surface of the substrate. It is formed
And the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive and a radiation polymerizable compound.
Adhesive sheet for attaching a wafer, characterized by comprising:
G. 2. The radiation attenuating layer has a radiation transmittance of 1
The pressure-sensitive adhesive sheet for attaching a wafer according to claim 1, wherein the content is from 90% to 90%.