JP2004001131A - Pressure sensitive adhesive sheet for manufacturing ic chip, and method for manufacturing ic chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure sensitive adhesive sheet for manufacturing an IC chip, which improves the handling ease of a semiconductor wafer during manufacturing steps of the IC chip, protects the semiconductor wafer by rigidly adhering to the same during application, and facilitates separation thereof after the application, and to provide a method for manufacturing the IC chip. <P>SOLUTION: The pressure sensitive adhesive sheet for manufacturing the IC chip consists of a substrate and a pressure sensitive adhesive layer formed on a single surface of the substrate. The substrate is self-supportable and flexible, and the pressure sensitive adhesive layer contains a gas generating agent which generates a gas upon the application of a stimulus thereto. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention can improve the handleability of a semiconductor wafer in a manufacturing process of an IC chip, and firmly adheres the semiconductor wafer during use to protect the semiconductor wafer and easily peels off after use. The present invention relates to an adhesive sheet for chip production and a method for producing an IC chip using the same.
[0002]
[Prior art]
A semiconductor integrated circuit (IC chip) is usually formed by slicing a high-purity semiconductor single crystal or the like into a semiconductor wafer, forming a predetermined circuit pattern on the surface of the semiconductor wafer using photoresist, and then forming a semiconductor wafer on the back surface. It is manufactured by polishing with a polishing machine to reduce the thickness of the semiconductor wafer to about 100 to 600 μm, and finally dicing to make chips.
[0003]
Here, at the time of polishing, an adhesive sheet (back grinding tape) is attached to the surface of the semiconductor wafer to protect a circuit pattern formed on the surface of the semiconductor wafer, to prevent damage to the semiconductor wafer, and to facilitate polishing. At the time of dicing, an adhesive sheet (dicing tape) is attached to the back side of the semiconductor wafer, and the semiconductor wafer is diced with the semiconductor wafer adhered and fixed. The formed chip is needled from the film substrate side of the dicing tape. And pick it up and fix it on the die pad. The pressure-sensitive adhesive sheets used at the time of polishing or dicing must have a strong adhesive force so that the semiconductor wafer can withstand an impact at the time of polishing or the like, and damage of the semiconductor wafer at the time of peeling is required. In order to prevent this, it has been required to satisfy the contradictory condition that it can be easily peeled.
[0004]
In recent years, as the use of IC chips has expanded, an extremely thin semiconductor wafer having a thickness of about 50 μm, which can be used for IC cards or stacked and used, has been required. However, a semiconductor wafer having a thickness of about 50 μm has a larger warp than a conventional semiconductor wafer having a thickness of about 100 to 600 μm and is more likely to be broken by an impact. Then, it may be damaged.
[0005]
A semiconductor wafer having a thickness of about 50 μm has a high risk of being damaged in a polishing process or a dicing process, which is easily affected by an impact, and is also easily damaged when a bump is formed on an electrode of an IC chip. For this reason, it has been an important issue to improve the handleability of the semiconductor wafer in the process of manufacturing IC chips from a thin semiconductor wafer having a thickness of about 50 μm.
[0006]
On the other hand, as a method of improving the handleability of a semiconductor wafer, a method of bonding a member such as a support plate with a double-sided tape to reinforce the semiconductor wafer, and the like can be mentioned. There has been a demand for further improvements.
[0007]
[Problems to be solved by the invention]
In view of the above situation, the present invention can improve the handleability of a semiconductor wafer in an IC chip manufacturing process, and firmly adheres and protects the semiconductor wafer during use, and easily peels off after use. It is an object of the present invention to provide an adhesive sheet for manufacturing an IC chip and a method for manufacturing an IC chip using the same.
[0008]
[Means for Solving the Problems]
The present invention is a pressure-sensitive adhesive sheet for IC chip production in which a pressure-sensitive adhesive layer is formed on one surface of a substrate, wherein the substrate is self-supporting and flexible, and the pressure-sensitive adhesive layer is This is a pressure-sensitive adhesive sheet for producing an IC chip, which contains a gas generating agent that generates a gas by giving a gas.
Hereinafter, the present invention will be described in detail.
[0009]
The pressure-sensitive adhesive sheet for producing an IC chip of the present invention is obtained by forming a pressure-sensitive adhesive layer on one surface of a substrate.
The substrate is self-supporting and flexible.
In the present specification, having the self-supporting means having such rigidity that deformation of the thin-film semiconductor wafer can be suppressed when the thin-film semiconductor wafer is supported, and the above-mentioned flexibility means In addition, it means that the semiconductor wafer has such a rigidity that it can be bent when the semiconductor wafer is separated from the substrate adhered by the pressure-sensitive adhesive sheet for IC chip production of the present invention.
As the material of the base material, for example, polyethylene terephthalate (PET) resin, olefin, vinyl chloride and the like are suitably used. When a polyethylene terephthalate resin is used, the base material transmits ultraviolet light. Therefore, when the gas generating agent described below generates a gas by stimulation by ultraviolet light, the base material is irradiated with ultraviolet light. Thereby, the adherend and the substrate can be separated.
[0010]
The thickness of the base material is not particularly limited as long as it balances rigidity and lightness. For example, when a polyethylene terephthalate resin is used, the thickness is preferably 150 μm or more.
A semiconductor wafer to which such an adhesive sheet for manufacturing an IC chip is bonded can obtain a strength that can withstand an impact in a manufacturing process of the IC chip without reinforcing by bonding a member such as a support plate. It is lighter than the case where members such as a support plate are bonded and reinforced, and the handleability of a semiconductor wafer which is easily damaged can be improved.
[0011]
The pressure-sensitive adhesive layer contains a gas generating agent that generates a gas by giving a stimulus.
Examples of the stimulus include stimuli such as light, heat, ultrasonic waves, and impact. Among them, stimulation by light or heat is preferred. Examples of the light include ultraviolet light and visible light. When using light stimulation as the above-mentioned stimulation, the pressure-sensitive adhesive layer containing the gas generating agent is preferably capable of transmitting or passing light. Although the gas generating agent is not particularly limited, for example, azo compounds and azide compounds are preferably used.
[0012]
Examples of the azo compound include 2,2′-azobis- (N-butyl-2-methylpropionamide) and 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-Hydroxyethyl] propionamide {, 2,2'-azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide}, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2′-azobis (N-butyl-2-methylpropionamide), 2,2'-azobis (N-cyclohexyl-2-methylpropionamide), 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloro Id, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] disulfatedi Hydrorate, 2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis {2- [1- (2- (Hydroxyethyl) -2-imidazoyl-2-yl] propane dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis (2-methylpropion) Amidine) hydrochloride, 2,2′-azobis (2-aminopropane) dihydrochloride, 2,2′-azobis [N- (2-carboxyacyl) -2- Tyl-propionamidyne], 2,2′-azobis {2- [N- (2-carboxyethyl) amidine] propane}, 2,2′-azobis (2-methylpropionamidooxime), dimethyl 2,2 ′ -Azobis (2-methylpropionate), dimethyl 2,2'-azobisisobutyrate, 4,4'-azobis (4-cyancarbonic acid), 4,4'-azobis (4-cyanopentanoic Acid), 2,2′-azobis (2,4,4-trimethylpentane) and the like.
In the production of IC chips, a step of performing high-temperature treatment is included if necessary, and among these, 2,2′-azobis- (N-butyl-2-methylpropionamide), which has a high thermal decomposition temperature, 2,2′-azobis (N-butyl-2-methylpropionamide) and 2,2′-azobis (N-cyclohexyl-2-methylpropionamide) are preferred.
These azo compounds generate nitrogen gas when stimulated by light, heat, or the like.
[0013]
Examples of the azide compound include 3-azidomethyl-3-methyloxetane, terephthalazide, p-tert-butylbenzazide; and glycidyl azide polymer obtained by ring-opening polymerization of 3-azidomethyl-3-methyloxetane. Polymers having an azide group are exemplified.
These azide compounds generate nitrogen gas by applying stimuli such as light, heat, ultrasonic waves, and impact.
[0014]
Among these gas generating agents, the azide compound described above has a problem that it is difficult to handle because it easily decomposes and gives off nitrogen gas even when subjected to impact. Further, once the azide compound starts to decompose, it causes a chain reaction and explosively releases nitrogen gas, which cannot be controlled. Therefore, the nitrogen gas generated explosively damages an adherend such as a semiconductor wafer. There is another problem. Due to these problems, the amount of the azide compound used is limited, but a limited amount of use may not provide a sufficient effect.
On the other hand, the azo compound, unlike the azide compound, does not generate gas by impact, and is therefore extremely easy to handle. In addition, gas is not explosively generated due to a chain reaction, so that adherends such as semiconductor wafers are not damaged, and gas generation can be interrupted by interrupting light irradiation. There is also an advantage that the adhesiveness can be controlled. Therefore, it is more preferable to use an azo compound as the gas generating agent.
[0015]
By containing the gas generating agent, when a stimulus is given to the pressure-sensitive adhesive layer, gas generated from the gas generating agent in the pressure-sensitive adhesive layer is released to the outside of the pressure-sensitive adhesive layer, and at least a part of the bonding surface is peeled off. , The adherend can be easily peeled off. At this time, it is preferable that all the gas generated from the gas generating agent is released to the outside of the pressure-sensitive adhesive layer and does not exist in the pressure-sensitive adhesive. However, as long as the pressure-sensitive adhesive does not foam and the cohesive force of the pressure-sensitive adhesive is significantly reduced, a part of the generated gas may be present as bubbles in the pressure-sensitive adhesive layer.
[0016]
When the pressure-sensitive adhesive layer contains, as the gas generating agent, a gas generating agent such as an azide compound or an azo compound that generates a gas when stimulated by light, it is preferable to further contain a photosensitizer. Since the photosensitizer has an effect of amplifying the light stimulus to the gas generating agent, the gas can be released by irradiation with less light. Further, since gas can be released by light in a wider wavelength range, even if the adherend does not transmit light of a wavelength that generates gas from an azide compound or azo compound such as polyimide, Gas can be generated by irradiating the light through this, and the range of choice of the adherend is expanded. The photosensitizer is not particularly limited, but, for example, a thioxanthone sensitizer is suitable. Note that the thioxanthone sensitizer can also be used as a photopolymerization initiator.
[0017]
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer containing the gas generating agent is not particularly limited. For example, it is preferable that the pressure-sensitive adhesive be formed of a pressure-sensitive adhesive that contains a polymerizable oligomer and has a reduced adhesive strength due to polymerization and crosslinking thereof. More preferably, the stimulus increases the elastic modulus. The stimulus for lowering the elastic modulus of the pressure-sensitive adhesive may be the same as the stimulus for generating a gas from the gas generating agent, or may be different from the stimulus for decomposing, for example, the azo compound or the azide compound. When a gas generating agent that simultaneously generates a gas and an active radical species is used, the active radical species generated by the decomposition of the azide compound acts on the polymerizable oligomer to promote polymerization crosslinking. More preferably, it is made of a thermoplastic resin. When a thermoplastic resin is used, the adhesive can be adhered to the adherend in a state where the adhesive is softened by heat.For example, the adhesive is adhered to the unevenness of the circuit pattern formed on the surface of the semiconductor wafer, and the adhesive is strongly adhered. You can gain power.
[0018]
As such an adhesive, for example, a polymerizable polymer of an alkyl acrylate type and / or an alkyl methacrylate type having a radical polymerizable unsaturated bond in a molecule and a radical polymerizable polyfunctional polymer A photocurable pressure-sensitive adhesive containing an oligomer or monomer as a main component and, if necessary, a photopolymerization initiator, or an alkyl acrylate ester having a radically polymerizable unsaturated bond in the molecule; and / or Alternatively, a thermosetting pressure-sensitive adhesive mainly composed of a methacrylic acid alkyl ester-based polymerizable polymer and a radically polymerizable polyfunctional oligomer or monomer and containing a thermal polymerization initiator may be used.
[0019]
Post-curing pressure-sensitive adhesives such as light-curing pressure-sensitive adhesives or heat-curing pressure-sensitive adhesives are uniformly and quickly polymerized and cross-linked by light irradiation or heating, so that they are integrated. The elastic modulus is significantly increased by curing, and the adhesive strength is greatly reduced. In addition, when gas is generated from a gas generating agent in a hard cured product, most of the generated gas is released to the outside, and the released gas peels off at least a part of the adhesive surface of the adhesive from the adherend and adheres. Decrease power.
[0020]
As the polymerizable polymer, for example, a (meth) acrylic polymer having a functional group in the molecule (hereinafter, also referred to as a (meth) acrylic polymer containing a functional group) is synthesized in advance, and the above functional group is included in the molecule. It can be obtained by reacting with a compound having a reactive functional group and a radical polymerizable unsaturated bond (hereinafter, also referred to as a functional group-containing unsaturated compound).
In addition, in this specification, a (meth) acrylic polymer shall mean an acrylic polymer and a methacrylic polymer.
[0021]
The functional group-containing (meth) acrylic polymer is a polymer having tackiness at room temperature, and is an acryl polymer having an alkyl group having a carbon number of usually 2 to 18 as in a general (meth) acrylic polymer. An acid alkyl ester and / or a methacrylic acid alkyl ester as a main monomer, and a functional group-containing monomer and, if necessary, another copolymerizable monomer copolymerizable therewith by a conventional method. It is obtained. The weight average molecular weight of the functional group-containing (meth) acrylic polymer is usually about 200,000 to 2,000,000.
[0022]
Examples of the functional group-containing monomer include a carboxyl group-containing monomer such as acrylic acid and methacrylic acid; a hydroxyl group-containing monomer such as hydroxyethyl acrylate and hydroxyethyl methacrylate; and an epoxy group-containing monomer such as glycidyl acrylate and glycidyl methacrylate. Monomers; isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate; and amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate.
[0023]
Examples of other copolymerizable modifying monomers include various monomers used in general (meth) acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.
[0024]
As the functional group-containing unsaturated compound to be reacted with the functional group-containing (meth) acrylic polymer, the same compound as the functional group-containing monomer described above according to the functional group of the functional group-containing (meth) acrylic polymer is used. it can. For example, when the functional group of the functional group-containing (meth) acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used, and when the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used. When the functional group is an amino group, an epoxy group-containing monomer is used.
[0025]
The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5,000 or less so that the three-dimensional network of the pressure-sensitive adhesive layer can be efficiently formed by light irradiation. And the number of radically polymerizable unsaturated bonds in the molecule is 2 to 6. Such more preferred polyfunctional oligomers or monomers include, for example, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate Alternatively, methacrylates similar to the above may be used. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylates, and methacrylates similar to those described above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.
[0026]
Examples of the photopolymerization initiator include those activated by irradiation with light having a wavelength of 250 to 800 nm. Examples of such photopolymerization initiators include acetophenone derivative compounds such as methoxyacetophenone. Benzoin ether compounds such as benzoin propyl ether and benzoin isobutyl ether; ketal derivative compounds such as benzyl dimethyl ketal and acetophenone diethyl ketal; phosphine oxide derivative compounds; bis (η5-cyclopentadienyl) titanocene derivative compound, benzophenone and Michler's ketone , Chlorothioxanthone, todecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexylphenylketone, 2-hydroxymethylphenylpro Examples include a photo-radical polymerization initiator such as bread. These photopolymerization initiators may be used alone or in combination of two or more.
[0027]
Examples of the thermal polymerization initiator include those which generate an active radical which is decomposed by heat to initiate polymerization curing. Specific examples thereof include dicumyl peroxide, di-t-butyl peroxide, and t-butyl. Examples include peroxybenzoyl, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, di-t-butyl peroxide and the like. Among them, cumene hydroperoxide, paramenthane hydroperoxide, di-t-butyl peroxide, and the like are preferable because of high thermal decomposition temperature. Among these thermal polymerization initiators, commercially available ones are not particularly limited, but for example, perbutyl D, perbutyl H, perbutyl P, permentor H (all of these are manufactured by NOF Corporation) and the like are preferable. These thermal polymerization initiators may be used alone or in combination of two or more.
[0028]
In the post-curing pressure-sensitive adhesive, in addition to the above components, for the purpose of adjusting the cohesive force as a pressure-sensitive adhesive, isocyanate compounds, melamine compounds, various kinds of compounds that are blended into a general pressure-sensitive adhesive such as an epoxy compound, if desired. A polyfunctional compound may be appropriately blended. Known additives such as a plasticizer, a resin, a surfactant, a wax, and a fine particle filler can also be added.
[0029]
The method for producing the pressure-sensitive adhesive sheet for IC chip production of the present invention is not particularly limited. For example, the pressure-sensitive adhesive sheet can be produced by forming a layer made of a pressure-sensitive adhesive containing a gas generating agent on a base material.
[0030]
The application of the pressure-sensitive adhesive sheet for manufacturing an IC chip of the present invention is not particularly limited. For example, when processing an extremely thin semiconductor wafer having a thickness of about 50 μm into an IC chip, a surface opposite to a surface to be polished is protected. When used as a back-grinding tape, it is possible to prevent breakage of the semiconductor wafer and ensure good processing. The adhesive sheet for manufacturing an IC chip of the present invention, which is a back-grinding tape for protecting the surface of the semiconductor wafer opposite to the surface to be polished in the polishing step of the semiconductor wafer, is also one of the present invention.
[0031]
Examples of the semiconductor wafer include those made of silicon, gallium arsenide, and the like.
The thickness of the semiconductor wafer is not particularly limited, but the thinner the semiconductor wafer, the more easily the effect of preventing breakage is exhibited, and the thickness after polishing is about 50 μm, for example, a semiconductor wafer having a thickness of 20 to 80 μm. Excellent breakage prevention effect is exhibited.
[0032]
A method for producing an IC chip using the pressure-sensitive adhesive sheet for producing an IC chip of the present invention is, for example, by the following steps.
First, the adhesive sheet for producing an IC chip of the present invention is attached to a semiconductor wafer. The surface to be affixed is the surface on which the circuit pattern has been formed in advance, opposite to the surface to be polished. By adhering the adhesive sheet for manufacturing an IC chip of the present invention, it is possible to prevent the circuit pattern from being damaged during polishing and the semiconductor wafer itself from being damaged.
[0033]
Subsequently, the semiconductor wafer to which the adhesive sheet for manufacturing an IC chip of the present invention is attached is fixed to a polishing apparatus, and the semiconductor wafer is polished. Polishing is usually performed until the semiconductor wafer has a thickness of about 100 to 600 μm, but may be polished to a thickness of 50 μm or less.
[0034]
When the polishing is completed, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for producing an IC chip of the present invention is stimulated to reduce the adhesive strength. Examples of the stimulus include light, heat, ultrasonic waves, and impact. When a transparent base material is used, the stimulus can be given by irradiating light from the base material side.
By applying the stimulus, a gas is generated from the gas generating agent contained in the pressure-sensitive adhesive layer, and the gas generated from the gas generating agent peels off at least a part of the bonding surface, whereby the adhesive force is reduced.
[0035]
Finally, the adhesive sheet for producing an IC chip of the present invention is peeled off from the semiconductor wafer. By giving the above stimulus, the adhesive force of the adhesive layer of the present invention can be easily removed from the semiconductor wafer because the adhesive strength of the adhesive layer is reduced.
At least such a step of attaching the pressure-sensitive adhesive sheet for IC chip production of the present invention to a semiconductor wafer, and a step of polishing the semiconductor wafer by fixing the semiconductor wafer to which the pressure-sensitive adhesive sheet for IC chip production is adhered to a polishing apparatus. After polishing, stimulating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for IC chip production attached to the semiconductor wafer to reduce the adhesive strength, and removing the pressure-sensitive adhesive sheet for IC chip production from the semiconductor wafer. A method for manufacturing an IC chip having a step of peeling is also an aspect of the present invention.
[0036]
In the method for manufacturing an IC chip of the present invention, if necessary, the steps which are usually performed may be omitted or the order of the steps may be different from the order of the steps. A dicing tape may be attached to the polished semiconductor wafer before peeling off the adhesive sheet for producing an IC chip, and then the peeling may be performed after peeling off the adhesive sheet for producing an IC chip of the present invention from the semiconductor wafer. The polishing may be performed before the wafer is formed into chips in the polishing process.
[0037]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
[0038]
(Example 1)
<Preparation of adhesive>
The following compounds were dissolved in ethyl acetate, and the mixture was polymerized by irradiation with ultraviolet rays to obtain an acrylic copolymer having a weight average molecular weight of 700,000.
3.5 parts by weight of 2-isocyanatoethyl methacrylate was added to 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained acrylic copolymer to cause a reaction, and further, the resin of the ethyl acetate solution after the reaction was added. 40 parts by weight of pentaerythritol triacrylate, 5 parts by weight of a photopolymerization initiator (Irgacure 651) and 0.5 part by weight of polyisocyanate are mixed with 100 parts by weight of the solid content to prepare an ethyl acetate solution of the pressure-sensitive adhesive (1). did.
79 parts by weight of butyl acrylate
15 parts by weight of ethyl acrylate
Acrylic acid 1 part by weight
5 parts by weight of 2-hydroxyethyl acrylate
0.2 parts by weight of photopolymerization initiator
(Irgacure 651, 50% ethyl acetate solution)
Lauryl mercaptan 0.01 parts by weight
[0039]
30 parts by weight of 2,2'-azobis- (N-butyl-2-methylpropionamide) and 2,4-diethylthioxanthone are based on 100 parts by weight of the resin solid content of the ethyl acetate solution of the pressure-sensitive adhesive (1). 3.6 parts by weight were mixed to prepare an ethyl acetate solution of the pressure-sensitive adhesive (2) containing the azo compound.
[0040]
<Preparation of adhesive sheet for IC chip production>
An ethyl acetate solution of the pressure-sensitive adhesive (2) is applied with a doctor knife so that the thickness of the dry film is about 25 μm on the surface of the 188-μm-thick olefin film which has been subjected to the easy-adhesion treatment on one side. Coating was performed, the solvent was evaporated, and the coating solution was dried. Next, a PET film subjected to a release treatment was attached to the surface of the pressure-sensitive adhesive (2) layer. The dried pressure-sensitive adhesive layer showed tackiness in a dry state. Thereafter, curing was carried out at 40 ° C. for 3 days to obtain an adhesive sheet for producing IC chips.
[0041]
<Polishing of semiconductor wafer>
The PET film for protecting the pressure-sensitive adhesive (2) layer of the pressure-sensitive adhesive sheet for producing an IC chip was peeled off, and attached to a silicon wafer having a diameter of 20 cm and a thickness of about 750 μm.
Next, the silicon wafer attached to the adhesive sheet for IC chip production was attached to a polishing apparatus, and polished until the thickness of the silicon wafer became about 50 μm. The silicon wafer was removed from the polishing device, and a dicing tape was stuck on the silicon wafer.
Next, using an ultrahigh-pressure mercury lamp from the olefin film side, the irradiation intensity of 365 nm ultraviolet rays on the olefin film surface was 40 mW / cm. ² Irradiation was performed for 2 minutes while adjusting the illuminance so that After the irradiation, the adhesive sheet for manufacturing an IC chip was peeled off from the silicon wafer.
The pressure-sensitive adhesive sheet for IC chip production could be easily peeled off after irradiation with ultraviolet rays without peeling off during the polishing step.
[0042]
(Example 2)
<Preparation of adhesive>
30 parts by weight of 3-azidomethyl-3-methyloxetane and 3.6 parts by weight of 2,4-diethylthioxanthone are based on 100 parts by weight of the resin solid content of the ethyl acetate solution of the pressure-sensitive adhesive (1) prepared in Example 1. The parts were mixed to prepare an ethyl acetate solution of the pressure-sensitive adhesive (3) containing the azide compound.
[0043]
<Preparation of adhesive sheet for IC chip production>
An ethyl acetate solution of the pressure-sensitive adhesive (3) is applied with a doctor knife so that the thickness of the dry film becomes about 25 μm on the surface of the 188-μm-thick olefin film on which the easy adhesion treatment is performed on one side. Coating was performed, the solvent was evaporated, and the coating solution was dried. Next, a PET film subjected to a release treatment was attached to the surface of the pressure-sensitive adhesive (3) layer. The dried pressure-sensitive adhesive layer showed tackiness in a dry state. Thereafter, curing was carried out at 40 ° C. for 3 days to obtain an adhesive sheet for producing IC chips.
[0044]
<Polishing of semiconductor wafer>
The PET film for protecting the pressure-sensitive adhesive (3) layer of the pressure-sensitive adhesive sheet for IC chip production was peeled off, and was adhered to a silicon wafer having a diameter of 20 cm and a thickness of about 750 μm.
Next, the silicon wafer attached to the adhesive sheet for IC chip production was attached to a polishing apparatus, and polished until the thickness of the silicon wafer became about 50 μm. The silicon wafer was removed from the polishing device, and a dicing tape was stuck on the silicon wafer.
Next, using an ultrahigh-pressure mercury lamp from the olefin film side, the irradiation intensity of 365 nm ultraviolet rays on the olefin film surface was 40 mW / cm. ² Irradiation was performed for 2 minutes while adjusting the illuminance so that After the irradiation, the adhesive sheet for manufacturing an IC chip was peeled off from the silicon wafer.
The pressure-sensitive adhesive sheet for IC chip production could be easily peeled off after irradiation with ultraviolet rays without peeling off during the polishing step.
[0045]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the handleability of a semiconductor wafer in the manufacturing process of an IC chip can be improved, and the semiconductor wafer can be firmly adhered during use to protect the semiconductor wafer and easily peeled off after use. It is possible to provide a pressure-sensitive adhesive sheet for manufacturing an IC chip and a method for manufacturing an IC chip using the same.

Claims (4)

An adhesive sheet for manufacturing an IC chip, wherein an adhesive layer is formed on one surface of a substrate,
The substrate is self-supporting, and flexible,
The pressure-sensitive adhesive sheet for IC chip production, wherein the pressure-sensitive adhesive layer contains a gas generating agent that generates a gas by applying a stimulus. The pressure-sensitive adhesive sheet according to claim 1, wherein the gas generating agent is an azo compound or an azide compound. 3. The pressure-sensitive adhesive sheet for IC chip production according to claim 1, wherein the backing tape is a back-grinding tape that protects a surface of the semiconductor wafer opposite to a surface to be polished in the polishing step. at least,
Attaching the pressure-sensitive adhesive sheet for producing an IC chip according to claim 1 to a semiconductor wafer;
A step of polishing the semiconductor wafer by fixing the semiconductor wafer to which the adhesive sheet for IC chip production has been attached to a polishing apparatus;
After polishing is completed, a step of stimulating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for IC chip production attached to the semiconductor wafer to reduce the adhesive strength,
Separating the pressure-sensitive adhesive sheet for IC chip production from the semiconductor wafer.