JPH04233249A - Adhesive sheet for wafer application - Google Patents

Abstract

PURPOSE:To prevent the generation of stretches and rumples in a dicing sheet at the time of semiconductor dicing, and obtain an adhesive sheet for a wafer application wherein dicing lines become not uniform and the adhesion between adhesive agent and base material does not decrease. CONSTITUTION:A heat-shrinkable film is used as at least one layer of the base material of a dicing sheet.

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 pasting wafers, and more particularly to a pressure-sensitive adhesive sheet for pasting wafers used for cutting and separating semiconductor wafers into small pieces.

0002

[Technical Background of the Invention] Semiconductor wafers such as silicon and gallium arsenide are manufactured in a large diameter state, and after this wafer is diced into small element pieces, it is transferred to the next process, a mounting process. . At this time, the semiconductor wafer is previously attached to an adhesive sheet and subjected to the steps of dicing, cleaning, drying, picking up, and mounting.

[0003] The adhesive sheet used in the process from the dicing process to the pick-up process for semiconductor wafers has sufficient adhesion to the wafer chips from the dicing process to the drying process, and has sufficient adhesion to the wafer chips during the pick-up process. It is desired that the adhesive has enough adhesive strength to prevent the adhesive from adhering to the chip.

[0004] As such an adhesive sheet, Japanese Patent Application Laid-open No. 6
0-196,956 and JP-A-60-223,
No. 139 discloses a pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive made of a low-molecular-weight compound having at least two photopolymerizable carbon-carbon double bonds in its molecule, which can be formed into a three-dimensional network by irradiation with light, is coated on the base material surface. Proposed. These proposals involve adhesive tapes in which a radiation-curable adhesive is coated on a radiation-transparent base material, and the radiation-curable compound contained in the adhesive is cured by radiation irradiation to form a three-dimensional network in the adhesive. This is based on the principle of imparting a chemical structure and significantly reducing its fluidity. According to the publication, low molecular weight compounds having at least two photopolymerizable carbon-carbon double bonds in the molecule include trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate. , dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or 1,4-
Examples include butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, and commercially available oligoester acrylate.

[0005] A pressure-sensitive adhesive sheet coated with a pressure-sensitive adhesive layer made of a low molecular weight compound having at least two photopolymerizable carbon-carbon double bonds in its molecule, as exemplified above,
The present inventors have discovered that there are the following problems.

[0006] That is, when irradiating with radiation such as ultraviolet rays,
In addition to ultraviolet rays, for example, infrared rays may be irradiated at the same time, and the resulting radiant heat causes the adhesive tape to stretch or partially wrinkle. These elongations and wrinkles are retained until the final process when the elements are picked up, which not only makes it impossible to store them in the carrier box used for transport between processes, but also causes variations in element spacing during the element pickup process. This also causes pickup failure of the generated element.

One possible means for solving the above-mentioned problems is to use a base material that has the property of shrinking due to heat. By using such a heat-shrinkable base material, elongation and wrinkles generated in the sheet can be absorbed, and troubles during pickup can be eliminated.

However, if the shrinkage of the base material is too large, the elongation and wrinkles will be eliminated, but the distance between elements (so-called dicing lines) caused by dicing will also become extremely narrow, which may cause pickup errors. Become. Further, if only the base material shrinks excessively, there is also the problem that the adhesiveness between the adhesive and the base material decreases.

[0009]

OBJECT OF THE INVENTION The present invention aims to solve the problems associated with the prior art as described above, and is capable of preventing sheet elongation and wrinkles caused by ultraviolet irradiation, etc. An object of the present invention is to provide a pressure-sensitive adhesive sheet for pasting wafers that does not become narrow or reduce the adhesion between the pressure-sensitive adhesive and the base material.

0010

SUMMARY OF THE INVENTION A first adhesive sheet for wafer adhesion according to the present invention is an adhesive sheet for wafer adhesion comprising a base material and an adhesive layer coated thereon, the base material having a shrinkage rate of 0.5. ~
It is characterized by being made of 20% heat-shrinkable film.

[0011] The second adhesive sheet for wafer adhesion according to the present invention has a base material having at least two or more constituent layers.
A pressure-sensitive adhesive sheet for pasting wafers coated with a pressure-sensitive adhesive layer is characterized in that at least one of the layers constituting the base material is made of a heat-shrinkable film with a shrinkage rate of 0.5 to 20%. .

0012

DETAILED DESCRIPTION OF THE INVENTION The adhesive sheet 1 according to the present invention, as shown in its cross-sectional view in FIG. A base material 2 consisting of a layer 3 or having at least two or more constituent layers, at least one of which is a heat-shrinkable film, and an adhesive layer 3 coated on the surface of the base material 2. In order to protect the adhesive layer 3 before use, it is preferable to temporarily adhere a releasable sheet 4 to the upper surface of the adhesive layer 3 as shown in FIG. 3.

The pressure-sensitive adhesive sheet according to the present invention can take any shape such as a tape shape or a label shape. The shrinkage rate of the heat-shrinkable film used in the present invention is 0.5 to 20%, preferably 1 to 10%. Shrinkage rate is 0.5%
If it is less than 20%, the elongation and wrinkles caused by radiant heat etc. will not be eliminated, while if it is more than 20%, the distance between the elements after shrinkage will become too narrow, and malfunctions will increase when picking up the elements.

[0014] Here, the shrinkage rate is a value measured as follows. That is, the heat-shrinkable film 100
It is heated at ℃ for 1 minute and calculated based on the following formula 1 from the dimensions before heating and the dimensions after heating.

[0015]

[Math 1]

Various types of such heat-shrinkable films have been known in the past, but in the present invention,
In general, any material can be used as long as it does not have an adverse effect on the wafer, such as ion contamination, and is not damaged by the push-up of the needle during pick-up. Specifically, films of polyethylene, polypropylene, nylon, urethane, polyvinyl chloride, etc. can be exemplified, and preferably films of nylon or urethane can be exemplified.

[0017] The thickness of the heat-shrinkable film as described above is
Usually 10 to 100 μm, preferably 15 to 80 μm
It is m. Furthermore, when the base material 2 of the adhesive sheet for wafer attachment according to the present invention is composed of two or more constituent layers, a layer other than the heat-shrinkable film (hereinafter referred to as non-heat-shrinkable film) to be laminated with the heat-shrinkable film as described above is used. Although there are no particular limitations on the shrinkable film, those with excellent water resistance and heat resistance are suitable, and synthetic resin films are particularly suitable.

Specific examples of such non-shrinkable films include polyolefin films such as polyethylene film, polypropylene film, polybutene film, and polymethylpentene film; polyvinyl chloride film, polyethylene terephthalate film, polybutylene terephthalate film, polybutadiene film,
Polyurethane film, ethylene vinyl acetate film, etc. are used. Further, a polymer film containing a compound having a carboxyl group as a polymer constitutional unit or a laminate of this and a general-purpose polymer film can also be used.

The thickness of the non-shrinkable film as described above is:
Usually 10 to 100 μm, preferably 15 to 80 μm
It is m. The non-shrinkable film used in the present invention is a film whose shrinkage rate is less than 0.5%.

The difference between the heat-shrinkable film and the non-shrinkable film used in the present invention is that their shrinkage rates are different. For example, when manufacturing a polyethylene film, by appropriately setting the manufacturing conditions, etc., it is possible to manufacture two types of polyethylene films having different shrinkage rates.

When the base material 2 of the adhesive sheet for attaching wafers according to the present invention is composed of two or more constituent layers, the above-mentioned heat-shrinkable film and the above-mentioned non-shrinkable film are combined. Lamination is performed by bonding via an adhesive or the like. The stacking order of these layers is not particularly limited, and various combinations can be adopted.

Combinations of the base material 2 consisting of two or more constituent layers include: polyolefin film/heat-shrinkable film, polyolefin film/heat-shrinkable film/polyolefin film, polyvinyl chloride film/heat-shrinkable film, polyolefin film/ Heat-shrinkable film/polyvinyl chloride film polyethylene terephthalate film/heat-shrinkable film polyethylene terephthalate film/heat-shrinkable film/polyethylene terephthalate film polyethylene terephthalate film/heat-shrinkable film/polyvinyl chloride film, etc., laminated in this order. A base material can be mentioned.

[0023] Base material 2 formed by laminating such constituent layers
Although the thickness is not particularly limited, it is usually 20 to 200μ.
m, preferably 50 to 100 μm. As described later, the adhesive sheet of the present invention is irradiated with radiation such as EB or UV when used. In the case of EB irradiation, the base material 2 does not need to be transparent;
When used with V irradiation, it needs to be transparent.

[0024] By providing an adhesive layer on the base material 2 having the above-mentioned structure, the adhesive sheet for wafer attachment according to the present invention can be obtained. In addition, when the base material 2 consists of two or more constituent layers, it is preferable to provide an adhesive layer on the non-shrinkable film side. Adhesive sheets for wafer adhesion with such a configuration can prevent stretching and wrinkles that occur in the sheet, prevent the dicing line from becoming extremely narrow, and improve the adhesion between the adhesive and the base material. never decreases.

[0025] An adhesive layer 3 is provided on the base material 2 as described above. As the adhesive constituting the adhesive layer 3, conventionally known adhesives can be widely used, but acrylic adhesives are preferred, and specifically, homopolymers containing acrylic acid ester as the main monomer unit are preferred. and copolymers selected from acrylic polymers and other functional monomers, and mixtures of these polymers are used. For example, acrylic esters include ethyl methacrylate, butyl methacrylate, and 2-methacrylate.
Ethylhexyl, glycidyl methacrylate, 2-hydroxyethyl methacrylate, etc., and those in which the above-mentioned methacrylic acid is replaced with acrylic acid, for example, can also be preferably used.

Furthermore, in order to increase the compatibility with the oligomers described later, monomers such as acrylic acid, methacrylic acid, acrylonitrile, and vinyl acetate may be copolymerized. The molecular weight of the acrylic polymer obtained by polymerizing these monomers is 2.0 x 105 to 10.0 x 105.
and preferably 4.0×105 to 8.0×105
It is.

By including a radiation-polymerizable compound in the adhesive layer as described above, the adhesive force can be reduced by irradiating the adhesive layer with radiation after cutting and separating the wafer. Such radiation-polymerizable compounds include molecules that can be formed into a three-dimensional network by light irradiation, such as those disclosed in JP-A-60-196,956 and JP-A-60-223,139. Low molecular weight compounds having at least two or more photopolymerizable carbon-carbon double bonds are widely used, and specifically, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, Dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, etc. are used.

Furthermore, as the radiation polymerizable compound, in addition to the above-mentioned acrylate compounds, urethane acrylate oligomers can also be used. The urethane acrylate oligomer is composed of 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 - A terminal isocyanate urethane prepolymer obtained by reacting xylylene diisocyanate, diphenylmethane 4,4-diisocyanate, etc. with an acrylate or methacrylate having a hydroxyl group, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate , 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, etc. This urethane acrylate oligomer is a radiation polymerizable compound having at least one carbon-carbon double bond.

[0029] Such urethane acrylate oligomers have a molecular weight of 3,000 to 30,000, preferably 3,000 to 10,000, more preferably 400.
It is preferable to use one having a molecular weight of 0 to 8000, since even if the semiconductor wafer surface is rough, the adhesive will not adhere to the chip surface when the wafer chip is picked up. Furthermore, when using a urethane acrylate oligomer as a radiation polymerizable compound, JP-A-60-196,95
Compared to the case of using a low molecular weight compound having at least two photopolymerizable carbon-carbon double bonds in the molecule as disclosed in Publication No. 6, an extremely superior pressure-sensitive adhesive sheet can be obtained. That is, the adhesive strength of the adhesive sheet before irradiation with radiation is sufficiently large, and the adhesive strength decreases sufficiently after irradiation with radiation, so that no adhesive remains on the chip surface when a wafer chip is picked up.

The blending ratio of the acrylic adhesive and the urethane acrylate oligomer in the adhesive of the present invention is such that the urethane acrylate oligomer is used in an amount of 50 to 900 parts by weight per 100 parts by weight of the acrylic adhesive. It is preferable that In this case, the resulting pressure-sensitive adhesive sheet has a high initial adhesive strength, and the adhesive strength significantly decreases after radiation irradiation, making it possible to easily pick up wafer chips from the pressure-sensitive adhesive sheet.

If necessary, the adhesive layer 3 may contain, in addition to the above-mentioned adhesive and radiation polymerizable compound, a compound that is colored by radiation irradiation. By including a compound in the adhesive 3 that will be colored by such radiation irradiation, the adhesive sheet will be colored after being irradiated with radiation, and therefore the detection accuracy will be improved when detecting wafer chips with an optical sensor. This prevents malfunctions from occurring when picking up wafer chips. Furthermore, it is possible to immediately determine by visual inspection whether or not the adhesive sheet has been irradiated with radiation.

Compounds that are colored by radiation irradiation are compounds that are colorless or pale colored before irradiation, but become colored by irradiation with radiation, and preferred specific examples of these compounds include leuco dyes. As the leuco dye, conventional triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, and spiropyran-based dyes are preferably used. Specifically, 3-[N-(p
-tolylamino)]-7-anilinofluorane, 3-[
N-(p-tolyl)-N-methylamino]-7-anilinofluorane, 3-[N-(p-tolyl)-N-ethylamino]-7-anilinofluorane, 3-diethylamino-6 -Methyl-7-anilinofluorane, crystal violet lactone, 4,4',4"-trisdimethylaminotriphenylmethanol, 4,4',4"-trisdimethylaminotriphenylmethane, and the like.

Color developers preferably used in conjunction with these leuco dyes include electron acceptors such as conventionally used initial polymers of phenol-formalin resin, aromatic carboxylic acid derivatives, and activated clay. When changing the color former, various known coloring agents can be used in combination.

[0034] Such a compound that is colored by radiation irradiation may be dissolved in an organic solvent or the like and then included in the adhesive layer, or may be made into a fine powder and included in the adhesive layer. . This compound is contained in the adhesive layer from 0.01 to
It is desirable to use an amount of 10% by weight, preferably 0.5-5% by weight. If the compound is used in an amount exceeding 10% by weight, the radiation irradiated to the pressure-sensitive adhesive sheet will be absorbed too much by the compound, resulting in insufficient curing of the pressure-sensitive adhesive layer. is 0.01% by weight
If less than the amount used, the adhesive sheet may not be sufficiently colored during radiation irradiation, and malfunctions may easily occur when picking up wafer chips.

In some cases, the adhesive layer 3 may contain a light-scattering inorganic compound powder in addition to the above-mentioned adhesive and radiation-polymerizable compound. By including such a light-scattering inorganic compound powder in the adhesive layer 3, even if the surface of the adherend such as a semiconductor wafer turns gray or black for some reason, the adhesive sheet can be irradiated with radiation such as ultraviolet rays. Then, even in the gray or black areas, the adhesive strength is sufficiently reduced,
Therefore, it is possible to prevent the adhesive from adhering to the surface of the wafer chip when the wafer chip is picked up, and to have sufficient adhesive strength before irradiation with radiation.

[0036] This light-scattering inorganic compound
) or a compound that can diffusely reflect radiation such as an electron beam (EB) when irradiated with it, specifically, silica powder, alumina powder,
Examples include silica alumina powder and mica powder. The light-scattering inorganic compound is preferably one that almost completely reflects the radiation as described above, but it is of course possible to use one that absorbs radiation to some extent.

The light-scattering inorganic compound is preferably in powder form, and its particle size is 1 to 100 μm, preferably 1 to 2 μm.
It is desirable that the thickness be about 0 μm. This light-scattering inorganic compound is contained in the adhesive layer in an amount of 0.1 to 10% by weight, preferably 1% by weight.
Preferably, it is used in an amount of ˜4% by weight. If the compound is used in an amount exceeding 10% by weight in the adhesive layer, the adhesive strength of the adhesive layer may decrease;
If the amount is less than % by weight, when the surface of the semiconductor wafer turns gray or black, even if the area is irradiated with radiation, the adhesive strength may not be sufficiently reduced and adhesive may remain on the wafer surface when picked up.

The adhesive sheet obtained by adding light-scattering inorganic compound powder to the adhesive layer can be used even when the surface of a semiconductor wafer has become gray or black for some reason. It is thought that the reason why the adhesion force is sufficiently reduced even in this part when radiation is irradiated to the part that has become stained is considered to be as follows. That is, the adhesive sheet 1 according to the present invention has an adhesive layer 3, and when this adhesive layer 3 is irradiated with radiation, the radiation-polymerizable compound contained in the adhesive layer 3 hardens and the adhesive layer 3 is cured. power will decrease. However, gray or black areas may appear on the semiconductor wafer surface for some reason. In such a case, if the adhesive layer 3 is irradiated with radiation, the radiation will damage the adhesive layer 3.
However, if there is a gray or black area on the wafer surface, the radiation will be absorbed by this area and no longer reflected. For this reason, the radiation that should originally be used for curing the adhesive layer 3 is absorbed in the gray or blackened areas, resulting in insufficient curing of the adhesive layer 3 and the adhesive strength not decreasing sufficiently. become. Therefore, it is considered that the adhesive adheres to the chip surface when the wafer chip is picked up.

However, when a light-scattering inorganic compound powder is added to the adhesive layer 3, the irradiated radiation collides with the compound and changes its direction before reaching the wafer surface. Therefore, even if there is a gray or black area on the wafer chip surface, the diffusely reflected radiation will penetrate into the area above this area, and therefore this gray or black area will also be sufficiently cured. do. For this reason,
By adding light-scattering inorganic compound powder to the adhesive layer, even if there is a gray or black area on the semiconductor wafer surface for some reason, the adhesive layer will not be sufficiently cured in this area. Therefore, when the wafer chip is picked up, no adhesive is attached to the chip surface.

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

By including the above-mentioned abrasive grains in the base material, even if the cutting blade cuts into the base material and the adhesive adheres to the cutting blade, the abrasive effect of the abrasive grains will prevent clogging. Can be easily removed.

[0042] Furthermore, by mixing an isocyanate curing agent into the above adhesive, the initial adhesive strength can be set to an arbitrary value. Such hardening agents include
Specifically, polyvalent isocyanate compounds, 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, etc. are used.

Furthermore, in the case of UV irradiation, the above-mentioned pressure-sensitive adhesive may be mixed with a UV initiator to reduce the polymerization curing time and the amount of UV irradiation due to UV irradiation.

Specific examples of such UV initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Examples include benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, and β-chloroanthraquinone.

The method of using the pressure-sensitive adhesive sheet according to the present invention will be explained below. When a releasable sheet 4 is provided on the top surface of the adhesive sheet 1 according to the present invention, the sheet 4 is removed, and then the adhesive sheet 1 is placed with the adhesive layer 3 facing upward, as shown in FIG. As shown, a semiconductor wafer A to be diced is attached to the upper surface of this adhesive layer 3. Wafer A is subjected to various processes such as dicing, cleaning, and drying in this adhered state. At this time, since the wafer chips are sufficiently adhered and held to the adhesive sheet by the adhesive layer 3, the wafer chips will not fall off during each of the above 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. The radiation polymerizable compound contained in layer 3 is polymerized and cured. When the radiation-polymerizable compound is polymerized and cured by irradiating the adhesive layer 3 with radiation in this manner, the adhesive strength of the adhesive is greatly reduced, and only a small amount of adhesive strength remains.

It is preferable that the adhesive sheet 1 is irradiated with radiation from the side of the base material 2 on which the adhesive layer 3 is not provided. Therefore, as mentioned above, when using UV as radiation, the base material 2 needs to be light-transparent, but when using EB as radiation, base material 2 does not necessarily need to be light-transparent. do not have.

After irradiating the adhesive layer 3 in the areas where the wafer chips A1, A2, . . . (not shown), Figure 6
As shown in FIG. 1, the chip A1 to be picked up by the push-up needle 5 from the bottom surface of the base material 2 according to the conventional method...
is pushed up, this chip A1... is picked up by, for example, air tweezers 6, and is mounted on a predetermined base. In this way, wafer chips A1,
When picking up A2..., the wafer chip surface can be easily picked up without any adhesive attached to it, and good quality chips without contamination can be obtained. Note that radiation irradiation can also be performed at a pickup station.

It is not necessarily necessary to irradiate the entire surface of the wafer A at once, but it is also possible to irradiate the entire surface of the wafer A several times, for example,
After irradiating each wafer chip A1, A2, etc. to be picked up with a radiation tube that irradiates only the corresponding back surface to reduce the adhesive force of only the adhesive on that part, the push-up needle 5 is used. wafer chips A1, A2
You can also pick up items one by one by pushing them up. FIG. 7 shows a modification of the above radiation irradiation method.
In this case, the inside of the push-up needle rod 5 is hollow, and the radiation source 7 is provided in the hollow part so that radiation irradiation and pickup can be performed at the same time. At the same time, the pick-up operation time can be shortened.

[0050]

[Effects of the Invention] As explained above, the adhesive sheet for attaching wafers according to the present invention can prevent stretching and wrinkles of the sheet caused by ultraviolet irradiation, etc., and can prevent the dicing line from becoming extremely narrow. Therefore, the adhesiveness between the adhesive and the base material does not deteriorate.

[0051]

[Examples] The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

[0052]

[Example 1] Acrylic adhesive (copolymer of n-butyl acrylate and acrylic acid) 100 parts by weight and molecular weight 8
000 urethane acrylate oligomer, 10 parts by weight of a curing agent (diisocyanate type), and U
A pressure-sensitive adhesive composition was prepared by mixing with 10 parts by weight of a V curing reaction initiator (benzophenone type).

[0053] This adhesive composition was coated on a polyethylene terephthalate film having a thickness of 25 μm which had been subjected to a peeling treatment, at a coating amount of 15 g/m2 to a thickness of 10 μm, and after heating at 100° C. for 1 minute, the adhesive composition was coated to a thickness of 80 μm. The shrinkage rate of
% heat-shrinkable urethane film base material was attached to the adhesive layer side of the polyethylene terephthalate film to produce the adhesive sheet of the present invention.

The release-treated polyethylene terephthalate film was peeled off from the resulting adhesive sheet to expose the adhesive surface, a 5-inch silicon wafer was pasted on top of it, and it was adhered to a flat frame, and then it was cut with a 50 μm thick diamond blade. After full cutting and dicing into 5 mm square pieces, only the wafer portion from the substrate surface was irradiated with ultraviolet rays for 2 seconds (illuminance: 200 mW/cm 2 ). When the state of the sheet after UV irradiation was visually judged, no elongation or deflection was observed. The width of the dicing line was 50 μm. After 48 hours, the adhesive sheet did not come off from the flat frame and did not sag. The width of the dicing line was 48 μm.

[0055]

[Example 2] The same adhesive composition prepared in Example 1 was applied onto a release-treated polyethylene terephthalate film at a coating amount of 15 g/m2 to a thickness of 10 μm, and heated at 100°C for 1 minute. After that, the polyethylene film side of a base material having a thickness of 80 μm, which is made by laminating a polyethylene film and a heat-shrinkable nylon film with a shrinkage rate of 5%, is laminated to the adhesive layer side of the polyethylene terephthalate film. An adhesive sheet was produced.

Thereafter, the same operation as in Example 1 was carried out, and no elongation or bending was observed in the sheet after irradiation with ultraviolet rays. The width of the dicing line was 50 μm. The width of the dicing line after 48 hours was 43 μm.

[0057]

[Comparative Example 1] In Example 1, the base material had a thickness of 80 μm.
The same operation as in Example 1 was performed except that a base material consisting only of a polyethylene film of No. m was used.

It was confirmed that the sheet was bent after being irradiated with ultraviolet rays. The width of the dicing line is 50μm
Met. The width of the dicing line after 48 hours is 5
It was 0 μm.

[0059]

[Comparative Example 2] The same operation as in Example 1 was carried out, except that a base material having a thickness of 80 μm and made by laminating a polyethylene film and a heat-shrinkable polyethylene film with a shrinkage rate of 40% was used as the base material. Ta.

No elongation or bending was observed in the sheet after ultraviolet irradiation. The width of the dicing line was 50 μm. The width of the dicing line after 48 hours was 25 μm.

[Brief explanation of the drawing]

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

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

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

FIG. 4 is an explanatory diagram when the adhesive sheet according to the present invention is used from a semiconductor wafer dicing process to a pickup process.

FIG. 5 is an explanatory diagram when the adhesive sheet according to the present invention is used from a semiconductor wafer dicing process to a pickup process.

FIG. 6 is an explanatory diagram when the adhesive sheet according to the present invention is used from a semiconductor wafer dicing process to a pickup process.

FIG. 7 is an explanatory diagram when the adhesive sheet according to the present invention is used from a semiconductor wafer dicing process to a pickup process.

[Explanation of symbols]

1... Adhesive sheet 2...Base material 3...Adhesive layer 4...Release sheet A...Wafer B...Radiation

Claims (3)

[Claims] 1. A pressure-sensitive adhesive sheet for wafer attachment comprising a pressure-sensitive adhesive layer coated on a base material, characterized in that the base material is made of a heat-shrinkable film having a shrinkage rate of 0.5 to 20%. Adhesive sheet for attaching wafers. [Claim 2] In a pressure-sensitive adhesive sheet for wafer bonding, which is formed by coating a pressure-sensitive adhesive layer on a base material having at least two or more constituent layers, at least one of the layers constituting the base material has a shrinkage rate of A pressure-sensitive adhesive sheet for wafer attachment, characterized in that it is made of a heat-shrinkable film having a heat-shrinkable film of 0.5 to 20%. 3. The wafer attachment method according to claim 1 or 2, wherein the heat-shrinkable film is made of at least one compound selected from polyethylene, polypropylene, nylon, urethane, and polyvinyl chloride. adhesive sheet.