JP2510416B2 - Semiconductor wafer dicing method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dicing a semiconductor wafer, and more particularly, to a dicing film after the semiconductor wafer is bonded and fixed to the dicing film with a relatively strong adhesive force. The present invention relates to a dicing method for a semiconductor wafer which can significantly reduce the adhesive force and can pick up the dice without leaving an adhesive residue on the obtained dice.

2. Description of the Related Art In manufacturing an integrated circuit, a semiconductor wafer, for example,
To cut a silicon wafer to a predetermined size, that is, to perform dicing to obtain a dice having a predetermined size,
A silicon wafer is placed on a pressure-sensitive adhesive sheet called a so-called dicing film, cut on the dicing film while being fixed by pressure-sensitive adhesion, and then picked up from the film, that is, peeled off. Therefore,
In order to accurately dice a silicon wafer, the dicing film has a strong adhesive force to the silicon wafer at the time of dicing, while the dicing film has a strong adhesive force when picking up the obtained dice from the dicing film. We need to be weak. Although not limited in any way, for example, in the dicing of a silicon wafer, the dicing film has an adhesive force of 100 to 500 g / 25 mm or more, while the dicing film has a dicing film thickness of about 20. It is said that it is desirable to have an adhesive force of about 50 g / 25 mm or less.

However, as described above, a pressure-sensitive adhesive capable of reducing the adhesive force thereof after being applied to the adherend surface has not yet been known, and accordingly, dicing that satisfies the required characteristics as described above is performed. Films have hitherto been unknown.

On the other hand, generally in the field of adhesives, a UV-crosslinkable adhesive comprising a photopolymerizable oligomer, a photopolymerizable monomer, a photopolymerization initiator and other additives is already known,
This is a solventless type, one-pack type adhesive, and is excellent in that it is fast-curing and does not require heating. However, in this adhesive, UV irradiation is originally an adhesive. It is carried out in order to develop the required adhesive strength.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As a result of intensive research conducted by the present inventors to obtain a pressure-sensitive adhesive that initially has a strong adhesive force and can reduce the adhesive force as needed, it is unexpected. In addition, it was found that a pressure-sensitive adhesive composition containing an elastic polymer, a UV-crosslinkable acrylic acid ester, and a polymerization initiator as main components, when the composition is irradiated with ultraviolet rays, its adhesive force is significantly reduced. .

Therefore, if a layer of the pressure-sensitive adhesive composition is formed on a base resin sheet that can transmit ultraviolet rays and is used as a dicing film, the dicing film has strong adhesion to a silicon wafer during dicing. On the other hand, the pressure-sensitive adhesive composition significantly reduces its adhesive strength by irradiating ultraviolet rays from the back surface of the dicing film after the dicing, so that the obtained dice can be easily picked up from the dicing film. You can

However, on the other hand, in such a method, when the wafer is adhered and fixed to the dicing film, air is introduced between the dicing film and the wafer, and when bubbles are formed, the pressure-sensitive adhesive composition is applied to the die separated from the dicing film. The thing remains, so-called glue remains.
Although it is not always clear, the UV-crosslinkable acrylic ester in the pressure-sensitive adhesive composition, which comes into contact with the wafer at the periphery of the bubbles, does not cure sufficiently even after the dicing film is irradiated with UV rays because of the bubbles (oxygen). The reaction is inhibited, the adhesive composition still retains sufficient adhesive force, and as a result, it is considered that adhesive transfer to the wafer and adhesive residue occurs, and at the same time, after dicing the wafer, When peeling the die from the dicing film, a large peeling force is still required.

In this way, when adhesive residue occurs on the die, it becomes difficult to connect the conductive wire to the die, or the thermal diffusivity from the chip after dicing becomes poor, and the reliability of the semiconductor device is reduced, In addition, it may cause failure.

Therefore, as a result of intensive studies for solving the above problems, the present inventors, as described above, use a dicing film having an adhesive composition whose adhesive force is remarkably reduced by irradiation of ultraviolet rays to form a semiconductor using a dicing film. The present invention has been completed by finding that when a wafer is bonded and fixed to a dicing film under an inert gas or under a vacuum when dicing the wafer, no adhesive residue is left on the dice.

Therefore, the present invention generally relates to a method for dicing a semiconductor wafer, and more particularly, to reduce the adhesive force of the dicing film after the semiconductor wafer is adhered and fixed to the dicing film with a relatively strong adhesive force, and after dicing. In addition, it is an object of the present invention to provide a dicing method for a semiconductor wafer capable of picking up a dice without leaving an adhesive residue on the obtained dicing.

Means for Solving the Problems A method for dicing a semiconductor wafer according to the present invention is a pressure-sensitive adhesive containing an elastic polymer, a UV-crosslinkable acrylic ester, and a polymerization initiator on a base resin sheet capable of transmitting UV rays. A semiconductor wafer is placed under an inert gas or under vacuum on a dicing film formed by forming a layer of the agent.
After the adhesive fixing and dicing, the back surface of the dicing film is irradiated with ultraviolet rays to reduce the adhesive force of the pressure-sensitive adhesive, and then the dice is picked up.

The dicing film used in the method of the present invention is
A layer of a pressure-sensitive adhesive composition containing, as a main component, an elastic polymer, a UV-crosslinkable acrylic ester, and a polymerization initiator is formed on a base sheet that can transmit UV rays,
If a semiconductor wafer is adhered and fixed to such a dicing film under an inert gas or under a vacuum, the dicing film has a strong adhesive force to enable highly accurate dicing before irradiation with ultraviolet rays, and after that, its back surface. By irradiating ultraviolet rays from the above, it is possible to significantly reduce the adhesive force to the die without causing adhesive residue in the obtained die, and thus, the die can be easily picked up in this way. The obtained die is clean and gives a highly reliable semiconductor device without causing any trouble in the subsequent processing.

 First, the pressure-sensitive adhesive composition will be described.

Conventionally, various pressure-sensitive adhesive compositions are known as described in, for example, "Adhesive Handbook (2nd Edition)" (edited by Japan Adhesive Association, published by Nikkan Kogyo Shimbun, 1980), pages 398 to 414. However, a typical pressure-sensitive adhesive composition contains an elastic polymer as a main component, a tackifier or a plasticizer having good compatibility with the elastic polymer, and further, if necessary, a filler or an antioxidant. , A colorant and the like are uniformly mixed. In the present invention, as such an elastic polymer, a copolymer of a saturated copolymerized polyester resin, a polyacrylate and an acrylate can be particularly preferably used.

The saturated copolymer polyester resin is usually a saturated divalent carboxylic acid and two or more different saturated divalent carboxylic acids, as described in "Industrial Materials" Vol. 25, No. 11, pp. 101-106. It is a saturated copolymer resin having a relatively low glass transition point obtained by polycondensation with alcohol. Usually, an aromatic divalent carboxylic acid and an aliphatic divalent carboxylic acid are used in combination as the saturated divalent carboxylic acid, An aliphatic or alicyclic dihydric alcohol, that is, glycol is used as the saturated dihydric alcohol. Particularly, in the present invention, the aromatic divalent carboxylic acid / aliphatic divalent carboxylic acid molar ratio is 80/20 to 20/80,
A saturated copolyester resin obtained by polycondensing a saturated divalent carboxylic acid mixture of 70/30 to 50/50 and glycol in an equimolar amount is preferably used. In the present invention, terephthalic acid is used as the aromatic divalent carboxylic acid, sebacic acid, adipic acid is used as the aliphatic polycarboxylic acid, ethylene glycol, 1,4-butanediol, propylene glycol, etc. Polymerized polyester resin is preferably used.
Incidentally, in the production of the saturated copolyester resin, a trivalent or higher polyvalent saturated carboxylic acid or a trivalent or higher polyhydric alcohol may be partially used in combination, if necessary.

The polyacrylic acid ester or acrylic acid copolymer includes any of those used as an elastic polymer as a main component in a pressure-sensitive adhesive conventionally known as an acrylic pressure-sensitive adhesive. The polymer used as the elastic polymer in the acrylic pressure-sensitive adhesive is generally substantially an acrylate copolymer. This copolymer is usually ethyl acrylate, which forms a polymer having a low glass transition point to make it tacky,
A comonomer that forms a hard polymer having a high glass transition point for imparting cohesiveness, using an alkyl acrylate such as butyl acrylate or 2-ethylhexyl acrylate as a main monomer, for example, vinyl acetate, acrylonitrile, styrene. , Methyl acrylate, methyl methacrylate, and the like, and monomers having functional groups such as carboxylic acid group, hydroxyl group, amide group, glycidyl group, and hydroxylmethyl group for improving crosslinkability and adhesiveness, such as acrylic acid. It is a copolymer obtained by copolymerizing monomers such as methacrylic acid, itaconic acid, hydroxylethyl methacrylate, hydroxypropyl methacrylate, acrylamide, and glycidyl methacrylate.

The UV-crosslinkable acrylic acid ester used in the present invention refers to an acrylic acid ester or a methacrylic acid ester as an oligomer or a monomer which is crosslinked by irradiation of ultraviolet rays, and has at least two acryloylme groups or methacryloyl groups in the molecule. Specifically, such oligomers include, for example, oligoester acrylates, and the monomers include, for example, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, dipentaerythritol hexaacrylate. Ester of polyhydric alcohol such as acrylate and acrylic acid, or
Examples include esters of methacrylic acid with polyhydric alcohols such as 1,6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, and dipentaerythritol pentamethacrylate.

The pressure-sensitive adhesive composition used in the present invention contains 15 to 200 parts by weight, preferably 50 to 150 parts by weight, of the above-mentioned UV-crosslinkable acrylic acid ester with respect to 100 parts by weight of the elastic polymer. For 100 parts by weight of the elastic polymer,
When the amount of the UV-crosslinkable acrylic acid ester is less than 15 parts by weight, even if the resulting adhesive composition is irradiated with ultraviolet rays, its adhesive strength does not substantially change, while when it exceeds 200 parts by weight. Can reduce the adhesion of the dicing film by UV irradiation, but
This is because the UV-crosslinkable acrylic acid ester may remain in the die during pick-up of the die after dicing the silicon wafer, which is not preferable.

The pressure-sensitive adhesive composition used in the present invention further contains a polymerization initiator or a photosensitizer and, if necessary, a polymerization inhibitor. The polymerization initiator is used to promote the crosslinking of the ultraviolet-crosslinkable acrylic ester by irradiation with ultraviolet light. Such a polymerization initiator is generally well known in the technical field of ultraviolet crosslinking polymerization, and in the present invention, a conventionally generally known polymerization initiator can be used. As a specific example of such a polymerization initiator,
For example, benzoin alkyl ethers such as benzoin methyl ether and benzoin isopropyl ether,
Examples thereof include aromatic oxyketones such as benzoin, benzyl and benzophenone, aromatic ketones, benzyl dimethyl ketal, polyvinyl benzophenone and the like, but are not limited thereto.

The thermal polymerization inhibitor is added as needed in order to prevent the UV-crosslinkable acrylic acid ester from being polymerized by heat, not by UV irradiation, for example, as such a polymerization inhibitor. Also, a conventionally known ordinary polymerization inhibitor can be used. Examples of such a polymerization inhibitor include picric acid, phenol,
Hydroquinone, hiddlequinone monomethyl ether, etc. can be used.

The amounts of the above-mentioned polymerization initiator and polymerization inhibitor to be added may be those generally used in the technical field of ultraviolet cross-linking polymerization. For example, the polymerization initiator is 1 per 100 parts by weight of the above-mentioned ultraviolet cross-linkable acrylic ester. ˜20 parts by weight, and the polymerization inhibitor is used in an amount of 0.1 to 1 part by weight, if necessary.

The pressure-sensitive adhesive composition used in the present invention preferably further contains a tackifier. The tackifier that can be used is not particularly limited, and those conventionally used in the production of pressure-sensitive adhesive compositions generally called pressure-sensitive adhesives are appropriately used. As such a tackifier, for example, xylene resin, rosin or polymerized rosin, hydrogenated rosin,
Modified rosin resin such as rosin ester, terpene resin,
Examples thereof include terpene resins such as terpene phenol resins and rosin phenol resins, aliphatic, aromatic and alicyclic petroleum resins, coumarone resins, styrene resins and alkylphenol resins. The tackifier is usually used in the range of 10 to 200 parts by weight with respect to 100 parts by weight of the elastic polymer. When the compounding amount of the tackifier is too small, the adhesive force or the adhesive force is insufficient. On the other hand, when the compounding amount is too large, the decrease in the adhesive force after irradiating the resulting adhesive composition with ultraviolet rays is small. Also, when such an adhesive composition is applied to a dicing film, the tackifier may remain in the dice when picking up the dice after dicing the silicon wafer, which is not preferable.

The pressure-sensitive adhesive composition used in the present invention contains an elastic polymer, a UV-crosslinkable acrylic ester and a polymerization initiator in the above-mentioned blending amounts, if necessary, a tackifier, a polymerization inhibitor, a filler, and an aging agent. It can be obtained by dissolving together with an inhibitor, a colorant and the like in an appropriate organic solvent capable of dissolving them, for example, aromatic hydrocarbons, ketones, or a mixture thereof. As the solvent, for example, specifically, a mixed solvent of toluene and methyl ethyl ketone is preferably used, but is not limited thereto.
The content of the elastic polymer in the adhesive composition is appropriately selected depending on the application etc., but is usually in the range of 10 to 50% by weight. However, it is not limited to this.

In particular, the elastic polymer and the tackifier are usually commercially available in the form of a solution, and since it is convenient to use these, for example, these solutions are mixed, and the ultraviolet-crosslinking acrylic acid is added to the mixture. The ester and the polymerization initiator, and if necessary, other additives may be added and mixed to form a uniform solution.

The dicing film used in the method of the present invention is
It can be obtained by forming a layer of the pressure-sensitive adhesive composition as described above on a base sheet capable of transmitting ultraviolet rays according to a conventional method.

The base sheet is not particularly limited as long as it can transmit ultraviolet rays, and various sheets can be used, but a transparent or translucent synthetic resin sheet is usually used. For example, a resin sheet made of vinyl chloride resin, vinyl chloride-vinylidene chloride copolymer resin, vinyl chloride-vinyl acetate copolymer resin, polyvinylidene chloride, polyolefin, polyvinyl alcohol, polyamide, polyester, polycarbonate, acetyl cellulose or the like is preferable. Used for.

Among the above-mentioned various base resin sheets, a resin sheet made of a polyvinyl chloride or vinyl chloride copolymer containing a plasticizer is flexible, and is also inexpensive, so that it is particularly preferable in the method of the present invention. It can be preferably used. In addition to the vinyl chloride resin sheet, there are some that can be suitably used as the base material sheet containing the plasticizer. For example, vinyl chloride-vinylidene chloride copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic acid ester copolymer resin, polyvinylidene chloride, acetyl cellulose and the like can be mentioned.

Here, the plasticizer is not particularly limited, for example, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, ditridecyl phthalate, phthalic acid diesters such as butylbenzyl phthalate, tricresyl phosphate, trioctyl. Phosphates such as phosphate, triphenyl phosphate, 2-ethylhexyl diphenyl phosphate, cresyl diphenyl osulfate, etc., dioctyl adipate, dioctyl seba keto, dioctyl azelate, tri-2-ethylhexyl acetylcitrate, etc. Polyester plasticizers such as fatty acid diesters, polypropylene adipates and polypropylene sebacates, epoxy plasticizers such as epoxidized soybean oil, chlorinated paraffins, chlorine plasticizers such as chlorinated fatty acid esters, etc. Rukoto can.

However, as described above, when a resin sheet containing a plasticizer is used as the base sheet of the dicing film, the plasticizer migrates from the resin sheet into the pressure-sensitive adhesive composition, and the plasticizer is usually used. Since the UV-crosslinkable acrylic ester and the UV-crosslinkable acrylic ester have good compatibility with each other, the UV-crosslinkable acrylic ester contained in the pressure-sensitive adhesive composition migrates into the resin sheet, and due to such mutual migration, the dicing film is formed. In some cases, the effect of reducing the adhesive strength after the UV irradiation is significantly reduced.

Therefore, in the present invention, when a resin sheet containing a plasticizer is used as the base sheet of the dicing film, ultraviolet rays are transmitted between the base sheet and the pressure-sensitive adhesive sheet, but the plasticizer is used. Also, it is preferable to interpose a barrier layer made of a resin layer that does not allow the UV-crosslinkable acrylic ester to pass therethrough.

That is, the barrier layer does not hinder the transmission of ultraviolet light at all, but prevents the plasticizer contained in the base resin sheet from migrating into the pressure-sensitive adhesive composition, and at the same time, the pressure-sensitive adhesive composition Prevents the ultraviolet-crosslinkable acrylic acid ester contained in the base resin sheet from migrating to the base resin sheet, thus holding the plasticizer contained in the base resin sheet in the base material, The UV-crosslinkable acrylic acid ester contained in the pressure-sensitive adhesive composition is retained in the adhesive composition to prevent the adhesive force of the pressure-sensitive adhesive sheet from decreasing with time due to ultraviolet irradiation.

As the barrier layer, a film of poly-α-olefin such as polyethylene or polypropylene, a film of polyalkylene terephthalate such as polyethylene terephthalate, or a resin coating film, for example, a resin coating layer such as a modified polyacrylic resin is preferably used. To be Therefore, the barrier layer is formed by pressing a film made of the above-exemplified resin on the base resin sheet, or by applying a melt of the resin and cooling, or by applying a solution of the above resin and drying. Yotsutte
Can be formed. Also, for example, a barrier layer can be obtained by applying a modified polyacrylic resin solution and, if necessary, heating and drying to form a coating film.

As the above-mentioned modified polyacrylic resin, various ones are conventionally known, but in the present invention, they are generally excellent in solvent resistance, and accordingly, are included in the ultraviolet-crosslinkable acrylic acid ester and the base resin sheet. An alkyd-modified polyacrylic resin that does not dissolve or swell in a plasticizer and a thermosetting polyacrylic resin are suitable. As the thermosetting polyacrylic resin, for example, an acid type, a hydroxyl group type, an epoxy type, an amide type and the like are suitably used.

However, in the present invention, the barrier layer, as described above, unless it substantially permeates the UV-crosslinkable acrylic ester contained in the pressure-sensitive adhesive composition and the plasticizer contained in the base resin sheet, In particular, it will be readily understood that the material is not limited, and the selection will depend on the particular UV-crosslinkable acrylic ester ester and plasticizer used in the present invention.

Therefore, the dicing film according to the present invention has, for example, a barrier resin layer laminated on a base resin sheet, and a solution of the pressure-sensitive adhesive composition as described above is applied onto the base sheet and dried. It can be obtained by doing.

According to the method of the present invention, a semiconductor wafer is placed on a dicing film as described above under an inert gas or under vacuum, and after pressure-sensitive adhesion and fixing, dicing is performed to obtain a dice having a predetermined size. After that, ultraviolet rays are irradiated from the back surface of the dicing film to reduce the adhesive force of the pressure-sensitive adhesive composition, and then the dice are picked up.
Here, as the inert gas, nitrogen, helium, argon or the like is used, but nitrogen is particularly preferable in practical use.

The means and method for irradiating the back surface of the dicing film with ultraviolet rays are not particularly limited, and may be the means and methods conventionally used conventionally in the technical field of ultraviolet curable resin coatings and ultraviolet curable adhesives. it can. For example, as the irradiation means, a xenon lamp, low pressure, medium pressure,
Use an ultraviolet source such as a high pressure or ultra high pressure mercury lamp,
Irradiation may be performed for several seconds to several minutes.

Effects of the Invention As described above, the pressure-sensitive adhesive composition containing the elastic polymer, the UV-crosslinkable acrylic acid ester, and the polymerization initiator as the main components is not necessarily clear for the reason, but is irradiated with UV rays. Before it has a strong adhesive force, the adhesive force is significantly reduced by the irradiation of ultraviolet rays.

Therefore, a dicing film having a layer of such a pressure-sensitive adhesive composition has an adhesive force of, for example, several hundred g / 25 mm at the beginning, but the adhesive force is remarkably reduced by the irradiation of ultraviolet rays, and in particular, the ultraviolet crosslinking property. Adhesive strength can be set to several tens of g / 25 mm by proper blending of acrylic acid ester. Therefore, by utilizing the strong adhesive force before the irradiation of ultraviolet rays, the dicing of the semiconductor wafer can be performed with high accuracy, and then the ultraviolet rays are irradiated from the back surface of the dicing film,
By reducing the adhesive strength of the dicing film,
The dice can be easily picked up from the dicing film. As described above, according to the method of the present invention, a die having excellent dimensional accuracy can be obtained with high productivity.

In particular, according to the method of the present invention, even if bubbles are formed between the dicing film and the wafer by adhesively fixing the semiconductor wafer to the dicing film under an inert gas or under a vacuum, the bubbles are Since it does not impede the effect of reducing the adhesive strength of the pressure-sensitive adhesive composition by UV irradiation, when the adherend is peeled off from the pressure-sensitive adhesive sheet after UV irradiation, there is no adhesive residue on the adherend and UV irradiation Therefore, the adhesive force can be always reduced without leaving any adhesive residue, and thus, according to the method of the present invention, a stable and highly reliable die can be obtained.

Example Hereinafter, an example will be shown, but the present invention is not limited to this example. In the examples, "parts" means "parts by weight".

Apply pressure-sensitive adhesive having the composition shown in Table 1 on release paper,
Dry at 120 ° C for 1 minute and apply pressure-sensitive adhesive layer as solid content 1
It was formed to a thickness of 0 μm.

When a saturated copolyester resin is used as the elastic polymer, the terephthalic acid / sebacic acid molar ratio is 70%.
Polycondensation of a 30/30 saturated divalent carboxylic acid mixture and ethylene glycol in equimolar amounts A resin having a glass transition point of about 10 ° C. was used.

When a polyacrylic acid ester or a copolymer of acrylic acid ester is used as an elastic polymer, an acrylic pressure-sensitive adhesive solution containing a polyacrylic acid ester or a copolymer of acrylic acid ester (Sanyo Chemical Co., Ltd. 610SA, polyacrylic acid ester or acrylic acid ester copolymer content of about 40% by weight) 100 parts by weight of photo-crosslinkable acrylic acid ester, polymerization initiator and photosensitizer are dissolved in the amounts shown in Table 1. Thus, a pressure sensitive adhesive composition was prepared.

This pressure-sensitive adhesive composition was applied on a release paper and dried at 120 ° C. for 1 minute to form a layer of the pressure-sensitive adhesive having a solid content of 10 μm.

Next, 100 parts of polyvinyl chloride having an average degree of polymerization of 1300, 35 parts of dioctyl phthalate or polyester plasticizer as a plasticizer and a vinyl chloride resin composition comprising an appropriate amount of a stabilizer are modified on a sheet having a thickness of 0.1 mm and modified. After applying an acrylic resin and drying to form a barrier layer, the pressure-sensitive adhesive layer according to the present invention is obtained by laminating the pressure-sensitive adhesive layer on the surface of the barrier layer of the base resin sheet. Obtained.

With respect to each of the pressure-sensitive adhesive sheets thus obtained, the release paper was peeled off, and then the adhesive force under various conditions was measured as follows.

Adhesive strength before UV irradiation A pressure-sensitive adhesive sheet is cut into a test piece with a width of 25 mm and a length of 100 mm. Under nitrogen, air bubbles are not formed between them, and this is placed on a stainless steel plate as an adherend. Then, the tape was reciprocated 5 times with a 3 kg roller to be pressed against it, and allowed to stand at room temperature for 20 minutes. Then, a 180 ° peel test was carried out with a shocker at a tensile speed of 300 mm / min.

Adhesive strength after UV irradiation When stacking a pressure-sensitive adhesive sheet on a stainless steel plate in the atmosphere or under nitrogen, air bubbles are forced to remain between the test piece and the stainless steel plate, and the vinyl chloride resin sheet side wavelength
After irradiating with ultraviolet light at 365 mμ, 120 W / cm for 7 seconds or 4 seconds, the test piece was peeled from the stainless steel plate, and the presence or absence of adhesive residue on the stainless steel plate was observed visually and by a 50 times microscope.

Further, in the same manner as above, when stacking the pressure-sensitive adhesive sheet on the stainless steel plate, a bubble large enough to obtain a test piece having a width of 25 mm and a length of 100 mm is forced between the sheet and the stainless steel plate. Of the vinyl chloride resin sheet was irradiated with ultraviolet rays at a main wavelength of 365 μm and 120 W / cm for 7 seconds.

Then, the pressure-sensitive adhesive sheet was cut into a width of 25 mm and a length of 100 mm to form a test piece, which was laid on a stainless steel plate so as not to form bubbles between them and reciprocated 5 times with a 3 kg roller to be pressed and brought into close contact. After being left at room temperature for 20 minutes, a 180 ° peel test was performed with a shocker at a tensile speed of 300 mm / min.

 The results are shown in Table 1.

According to the method of the present invention, when the adherend is adhered to an adherend and irradiated with ultraviolet rays and then the adherend is peeled off, no adhesive residue is left on the adherend. Further, as a result, the adhesive force after irradiation with ultraviolet rays is significantly reduced as compared with that before irradiation with ultraviolet rays. Therefore, according to the method of the present invention, after dicing a semiconductor wafer, the dice can be peeled from the dicing film with a stable and weak adhesive force, and the obtained dice is highly reliable.

On the other hand, according to an adhesion test in the atmosphere as a comparative example, the pressure-sensitive adhesive sheet was adhered to an adherend, and after the adherend was peeled off after irradiation with ultraviolet rays, the adherend was adhered to the adherend. Adhesive strength after ultraviolet irradiation is still high as well as adhesive residue.

Claims (5)

(57) [Claims] 1. An elastic polymer 100 made of a saturated polyester resin, a polyacrylic acid ester, or a copolymer of acrylic acid ester on a base resin sheet capable of transmitting ultraviolet rays.
15 parts by weight of UV-crosslinkable acrylic ester
On a dicing film formed by forming a layer of a pressure-sensitive adhesive containing 200 parts by weight and a polymerization initiator, the semiconductor wafer is placed under an inert gas or under vacuum and adhesively fixed, after dicing, After irradiating the back surface of the dicing film with ultraviolet rays to reduce the adhesive force of the pressure-sensitive adhesive,
A method for dicing a semiconductor wafer, which comprises picking up a dice. 2. The method of dicing a semiconductor wafer according to claim 1, wherein the pressure-sensitive adhesive contains a tackifier. 3. The method of dicing a semiconductor wafer according to claim 1, wherein the inert gas is nitrogen. 4. In a dicing film, a base resin sheet contains a plasticizer and is a resin sheet capable of transmitting ultraviolet rays, and contains an elastic polymer, an ultraviolet-crosslinkable acrylic ester and a polymerization initiator. The layer of pressure sensitive adhesive
The plasticizer and the UV-crosslinkable acrylic acid ester are not transmitted, but are formed on the base resin sheet through a resin layer that transmits UV rays. Method for dicing semiconductor wafer. 5. The method of dicing a semiconductor wafer according to claim 4, wherein the base resin sheet is a resin sheet made of polyvinyl chloride or a copolymer of vinyl chloride.