JP2011210944A - Antistatic adhesive tape for semiconductor processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antistatic adhesive tape for semiconductor processing, which causes little contamination on an adherend and little aging of an adhesive property as well as little influence to a surface of the adherend during dicing or back grinding treatment of a semiconductor component, and which can exhibit antistatic properties after ultraviolet curing even if an adhesive layer is thick.SOLUTION: The antistatic adhesive tape for semiconductor processing constituted by a base film and a photocuring adhesive layer includes: an antistatic layer containing a conductive polymer at least on one surface of the base film; and an adhesive layer containing a photocuring unsaturated carbon bond in a molecule of a base polymer on the antistatic layer, wherein a surface resistivity on the adhesive layer side before and after the ultraviolet curing is 1×10to 5×10Ω/square, a thickness of the adhesive layer is 20-250 μm, and a 90-degree peeling adhesive power of the adhesive layer after the ultraviolet curing when the adhesive tape adheres to a silicon mirror wafer is 0.15-0.25 N/25 mm.

Description

  The present invention relates to an adhesive tape for fixing a semiconductor having antistatic performance, and more particularly to an adhesive tape for dicing and backgrinding (backside grinding) having antistatic performance used when producing electrical, electronic and semiconductor parts. .

2. Description of the Related Art Conventionally, pressure-sensitive adhesive tapes for fixing and protecting parts in a dicing process and other processes when producing electrical, electronic parts, and semiconductor parts are known. As such an adhesive tape, a base film provided with a re-peelable acrylic adhesive layer, or a photo-curing type that has a strong resistance to external force when applied but can be peeled with a small force when peeled Some are provided with a releasable pressure-sensitive adhesive layer.
In the process using the adhesive tape, static electricity is generated due to peeling, friction, contact, etc. during peeling of the separator, back grinding, dicing, cleaning of cutting powder with ultra-pure water with high electrical insulation, and picking up. appear. In the case where the substrate of a component forming a circuit is an insulating material such as ceramics or glass, static electricity is not leaked quickly, and there is a concern about the occurrence of discharge breakdown of the circuit due to a short circuit or adhesion of foreign matters such as dust. Further, in recent years, with the thinning of wafers, circuits are highly integrated, the risk of circuit destruction due to static electricity increases, and the demand for antistatic adhesive tapes is increasing. In order to improve the static electricity trouble, static elimination devices such as ionizers have been introduced, but the actual situation is that sufficient antistatic effect has not been obtained, and it is desired to make the adhesive tape itself antistatic. Yes. Antistatic treated adhesive tape includes: adhesive tape with antistatic agent added to base film, adhesive tape with antistatic agent added to adhesive layer, antistatic between base film and adhesive layer An adhesive tape with an intermediate layer is used.

  As a technique for imparting antistatic properties to the pressure-sensitive adhesive tape, it is considered effective to apply it to the pressure-sensitive adhesive layer side in contact with the adherend instead of the base film side. However, when an antistatic agent such as a surfactant or a conductive filler is added to the adhesive, it is not only difficult to adjust or suppress the physical properties of the adhesive and its change over time, but the adhesive and the added material when peeling. There is a risk that it may move to the adherend and become contaminated. In this case, visible adhesive residue, microscopic level particulate matter, or liquid matter that cannot be observed optically occurs on the surface of the adherend, and adverse effects such as poor adhesion of parts in subsequent processes. Effect.

  In addition, by providing an antistatic layer containing a charge transfer boron polymer having a nitrogen atom-boron atom complex structure on one or both surfaces of the base film, contamination of the adherend with the adhesive or changes in adhesive physical properties over time An adhesive tape for fixing a semiconductor capable of providing an antistatic function without causing a decrease in reliability has been disclosed (see, for example, Patent Document 1). Although this tape can obtain a predetermined effect, the antistatic performance varies greatly depending on the humidity, and the adhesion between the base film and the antistatic layer is poor, and an improvement has been desired.

  In addition, by providing an antistatic layer containing a conductive polymer such as polythiophene or polypyrrole on one or both sides of the base film, the adherence of the adherend to the adherend or deterioration of the adhesive properties due to changes over time can be reduced. An adhesive tape for fixing a semiconductor capable of providing an antistatic function without occurring has been disclosed (see, for example, Patent Document 2 and Patent Document 3). This tape had no change in antistatic performance due to humidity, and there was no problem in the adhesion between the base film and the antistatic layer.

  In recent years, the unevenness of bumped wafers has increased due to diversification of mounting methods, and TSV wafers in which electrodes are formed on the back surface of semiconductor wafers have also emerged. Therefore, the adhesive tape for semiconductor processing has been required to have a thick adhesive layer in order to follow the unevenness. However, in the method of providing an antistatic layer containing a conductive polymer on one side or both sides of the base film, the antistatic layer is separated from the adherend when the pressure-sensitive adhesive layer is thick, so that sufficient anti-static is provided on the pressure-sensitive adhesive side. It was difficult to express the performance.

JP 2004-189769 A JP 2008-255345 A JP 2008-280520 A

  In the present invention, the contamination of the adherend and the change in adhesive properties with time are small, and there is little influence on the adherend surface even in dicing and backgrinding of semiconductor parts, and even if the adhesive layer is thick, antistatic after UV curing An object is to provide an antistatic semiconductor processing pressure-sensitive adhesive tape capable of exhibiting performance.

  As a result of intensive studies to achieve the above object, the present inventors have found that at least one surface of the base film contains a conductive polymer in the adhesive tape composed of at least the base film and the adhesive layer. An antistatic layer is formed, and a photocurable pressure-sensitive adhesive layer, in which the base polymer is a polymer containing a photocurable unsaturated carbon bond in the molecule, is formed on the antistatic layer, and is pulled 90 degrees after UV curing. Peeling adhesive strength (conforming to JIS Z 0237; peeling speed is 50 mm / min) is in the range of 0.15 to 0.25 N / 25 mm, so that antistatic performance is exhibited even when the pressure-sensitive adhesive layer is thick or after UV curing. Based on this finding, the present inventors have made the present invention.

That is, the present invention provides the following inventions.
(1) An adhesive tape comprising a base film and a photocurable adhesive layer, wherein the base film has an antistatic layer containing a conductive polymer on at least one surface, and a base on the antistatic layer. It has a pressure-sensitive adhesive layer containing a photocurable unsaturated carbon bond in the molecule of the polymer, and the surface resistivity on the pressure-sensitive adhesive layer side before and after UV curing is 1 × 10 ^{6 to} 5 × 10 ¹² Ω / □. The adhesive layer has a thickness of 20 to 250 μm, and when the adhesive tape is bonded to a silicon mirror wafer, the adhesive layer is peeled by 90 degrees after UV curing (according to JIS Z 0237; peeling) An adhesive tape for antistatic semiconductor processing, characterized in that the speed is from 0.15 to 0.25 N / 25 mm.
(2) 90 degree peeling adhesive strength (based on JIS Z 0237; peeling speed is 50 mm / min) after UV curing of the pressure-sensitive adhesive layer when the pressure-sensitive adhesive tape is bonded to a silicon mirror wafer, before UV-curing The adhesive tape for antistatic semiconductor processing according to (1), which has an adhesive strength of 4 to 15% of the 90 ° peel adhesive strength.
(3) When the pressure-sensitive adhesive tape is bonded to a silicon mirror wafer, the pressure-sensitive adhesive layer is peeled off by 90 degrees before UV curing (according to JIS Z 0237; peeling speed is 50 mm / min) is 1.4 N / The adhesive tape for antistatic semiconductor processing according to (1) or (2), wherein the adhesive tape exceeds 25 mm.

  The antistatic semiconductor processing pressure-sensitive adhesive tape of the present invention can exhibit antistatic performance even after UV curing even if the pressure-sensitive adhesive layer is thick. Therefore, a TSV wafer that requires a thick pressure-sensitive adhesive layer for processing. It can be used for processing a semiconductor having irregularities such as a (penetrating electrode wafer) and a wafer with bumps.

The fragmentary sectional view which shows embodiment of the adhesive tape for antistatic semiconductor processing which concerns on this invention.

  Hereinafter, the adhesive film (adhesive tape for fixing a semiconductor) of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing one embodiment of an antistatic semiconductor processing pressure-sensitive adhesive tape. As shown in FIG. 1, the antistatic semiconductor processing pressure-sensitive adhesive tape 1 of this embodiment comprises a photocurable pressure-sensitive adhesive layer 3, an antistatic layer 5 containing a conductive polymer, and a base film 7. The surface of the pressure-sensitive adhesive layer 3 is protected by applying an optional release liner 9 until it is used. When the antistatic layer 5 is provided on both sides, the pressure-sensitive adhesive layer 3 is formed on one side thereof.

In the antistatic semiconductor processing pressure-sensitive adhesive tape 1 of the present invention, the surface resistivity on the pressure-sensitive adhesive layer side before and after UV curing is preferably in the range of 1 × 10 ^{6 to} 5 × 10 ¹² Ω / □. If the surface resistivity is lower than 1 × 10 ⁶ Ω / □, the semiconductor is destroyed by overcurrent, and if it is higher than 5 × 10 ¹² Ω / □, the semiconductor is discharged and destroyed by charged static electricity.

Further, the ultraviolet curing referred to here is preferably cured by a high-pressure mercury lamp and cured at a dose of 200 mJ / cm ² , but is not limited thereto. The surface resistivity on the pressure-sensitive adhesive layer side before ultraviolet curing is preferably in the range of 3.0 × 10 ^{6 to} 3.2 × 10 ¹⁰ Ω / □, and the surface resistance on the pressure-sensitive adhesive layer side after ultraviolet curing. The rate is preferably in the range of 9.1 × 10 ^{7 to} 1.7 × 10 ¹² Ω / □. Furthermore, the change in the surface resistivity of the pressure-sensitive adhesive layer due to ultraviolet curing is preferably 100 times or less, and more preferably in the range of 10 to 91 times.

  In the antistatic semiconductor processing pressure-sensitive adhesive tape 1 of the present invention, holes or electrons are conducted on the π-conjugated main chain in the antistatic layer 2 containing a conductive polymer, and molecular chains are segmented in the pressure-sensitive adhesive layer 3. Protons are conducted by movement. Since the flexibility of the molecular chain of the pressure-sensitive adhesive layer 3 is significantly reduced by UV curing, the antistatic performance after UV curing is deteriorated. When the pressure-sensitive adhesive layer 3 is thick, it is difficult to develop the antistatic performance after UV curing. Met. However, the inventors can maintain the conductivity in the pressure-sensitive adhesive layer 3 if the molecular chain flexibility of the pressure-sensitive adhesive layer 3 is appropriately maintained even after UV curing, and even if the pressure-sensitive adhesive layer 3 is thick, it is antistatic. It was found that performance can be expressed. In order to keep the molecular chain flexibility in the pressure-sensitive adhesive layer 3 after photocuring appropriately, the base polymer of the pressure-sensitive adhesive needs to be a polymer containing a photocurable unsaturated carbon bond in the molecule.

  The polymer containing a photocurable unsaturated carbon bond in the molecule is mainly an acrylic copolymer having a group containing a hydroxyl group and a carboxyl group (hereinafter referred to as “acrylic copolymer (A)”). The thing made into a component is mentioned. The polymer containing an unsaturated carbon bond includes, for example, a carbon chain of a copolymer (A1) composed of (meth) acrylic acid ester, a hydroxyl group-containing unsaturated compound, a carboxyl group-containing unsaturated compound, etc. as a main chain. It can be obtained by addition reaction of a functional group capable of undergoing an addition reaction with respect to the functional group of the polymer (A1) and a compound (A2) having a photocurable unsaturated carbon bond. Therefore, it is difficult for a polymer containing a photocurable unsaturated carbon bond in a molecule to introduce many unsaturated carbon bonds on the molecule due to the influence of steric hindrance or the like. Therefore, if a polymer containing a photocurable unsaturated carbon bond is used as the adhesive base polymer, the photocurability is not high, and the flexibility of the adhesive can be kept moderate after UV curing. Afterwards, antistatic properties can be obtained.

  In addition, the smaller the amount of unsaturated carbon bonds in a polymer containing a photocurable unsaturated carbon bond, the higher the flexibility of the molecular chain of the pressure-sensitive adhesive layer after photocuring, and the better the antistatic performance after photocuring. become. Therefore, it is preferable that the unsaturated carbon bond amount of the base polymer of the adhesive used for an adhesive layer is 0.5 meq / g or less.

  As the (meth) acrylic acid ester which is a component of the acrylic copolymer (A), hexyl acrylate having 6 to 12 carbon atoms, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, decyl acrylate, Alternatively, pentyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, or a methacrylate similar to these can be listed as monomers having 5 or less carbon atoms. In this case, as the monomer having a larger carbon number is used as the monomer, the glass transition temperature becomes lower, so that a monomer having a desired glass transition temperature can be produced. In addition to the glass transition temperature, a low molecular compound having an unsaturated carbon bond such as vinyl acetate, styrene or acrylonitrile can be added within the range of 5% by mass or less for the purpose of improving compatibility and various performances.

Examples of the hydroxyl group-containing unsaturated compound include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and the like.
Examples of the carboxyl group-containing unsaturated compound include acrylic acid and methacrylic acid.

  As the functional group of the compound (A2) having a functional group capable of addition reaction and a photocurable unsaturated carbon bond, the functional group of the copolymer (A1) is a carboxyl group or a cyclic acid anhydride group. In some cases, a hydroxyl group, an epoxy group, an isocyanate group, and the like can be mentioned. In the case of a hydroxyl group, a cyclic acid anhydride group, an isocyanate group, and the like can be mentioned, and in the case of an amino group, an isocyanate group. And so on. Specific examples of the compound (A2) include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylates, 2-hydroxyalkyl methacrylates, glycol monoacrylates, glycol monoacrylate. Methacrylates, N-methylolacrylamide, N-methylolmethacrylamide, allyl alcohol, N-alkylaminoethyl acrylates, N-alkylaminoethyl methacrylates, acrylamides, methacrylamides, maleic anhydride, itaconic anhydride, fumaric anhydride Acid, phthalic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, polyisocyanate compound with a part of isocyanate group hydroxyl group or carboxyl group and photocuring It is possible to enumerate such as those urethanization with a monomer having a saturated carbon bonds.

  In the synthesis of the acrylic copolymer (A), as the organic solvent when the copolymerization is performed by solution polymerization, a ketone, ester, alcohol, or aromatic solvent can be used. Among them, generally good solvents for acrylic polymers, such as toluene, ethyl acetate, isopropyl alcohol, benzene methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, and solvents having a boiling point of 60 to 120 ° C. are preferable. A radical generator such as an azobis type such as' -azobisisobutylnitrile or an organic peroxide type such as benzoberperoxide is usually used. At this time, if necessary, a catalyst and a polymerization inhibitor can be used in combination. The polymerization temperature and the polymerization time are adjusted, and then an addition reaction at a functional group is performed, whereby an acrylic copolymer (A ) Can be obtained. In terms of adjusting the molecular weight, it is preferable to use a mercaptan or carbon tetrachloride solvent. The copolymerization is not limited to solution polymerization, and other methods such as bulk polymerization and suspension polymerization may be used.

Furthermore, the acrylic copolymer (A) may be copolymerized with monomers such as acrylonitrile and vinyl acetate for the purpose of controlling adhesiveness and cohesion. The weight average molecular weight of the acrylic copolymer (A) obtained by polymerizing these monomers is 5 × 10 ⁴ to 2 × 10 ⁶ , and preferably 1 × 10 ⁵ to 1 × 10 ⁶ .

  The pressure-sensitive adhesive layer 3 can set the adhesive force and the cohesive force to arbitrary values by further using a curing agent. Examples of such a curing agent include a polyvalent isocyanate compound, a polyvalent epoxy compound, a polyvalent aziridine compound, and a chelate compound. Specific examples of the polyvalent isocyanate compound include toluylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and those adduct types. Specific examples of the polyvalent epoxy compound include ethylene glycol diglycidyl ether, terephthalic acid diglycidyl ester acrylate, and the like. Specific examples of the polyvalent aziridine compound include tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, tris [1- (2-methyl) -aziridinyl] phosphine oxide, hexa [ 1- (2-Methyl) -aziridinyl] triphosphatriazine and the like are used. As the chelate compound, specifically, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) or the like is used. Moreover, it is preferable that 1-2 mass parts is contained with respect to 100 mass parts of photopolymerizable compounds (base polymer of an adhesive).

  Furthermore, by mixing a photoinitiator into the pressure-sensitive adhesive layer 3, it is possible to reduce the polymerization curing time by ultraviolet irradiation and the amount of ultraviolet irradiation. Specific examples of such photoinitiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β -Chloranthraquinone and the like. The photoinitiator is generally used in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the photopolymerizable compound. By irradiating the photocurable pressure-sensitive adhesive layer thus formed with light, preferably ultraviolet rays, the initial adhesive strength is greatly reduced, and the pressure-sensitive adhesive tape can be easily peeled off from the adherend. it can. Moreover, it is preferable that a photoinitiator is contained 1.5-2.5 mass parts with respect to 100 mass parts of photopolymerizable compounds (base polymer of an adhesive).

  The adhesive tape 1 for processing an antistatic semiconductor according to the present invention is bonded to a silicon mirror wafer, and the adhesive layer 3 is peeled off by 90 degrees before UV curing (according to JIS Z 0237; peeling speed is 50 mm / min) is preferably more than 1.4 N / 25 mm, more preferably 1.5 N / 25 mm or more, and still more preferably 1.8 N / 25 mm or more. This is because if the adhesive strength before UV curing is low, water may enter between the adhesive tape for semiconductor processing and the adherend during backside grinding.

The adhesive tape 1 for processing an antistatic semiconductor according to the present invention is bonded to a silicon mirror wafer, and the adhesive layer 3 is UV-cured after being peeled off by 90 degrees (according to JIS Z 0237; peeling speed is 50 mm) / Min) is preferably in the range of 0.15 to 0.25 N / 25 mm. As described above, antistatic performance can be exhibited by maintaining the flexibility of the molecular chain of the pressure-sensitive adhesive layer 3 even after UV curing. Therefore, when the adhesive strength is less than 0.15 N / 25 mm, the molecular chain flexibility of the pressure-sensitive adhesive layer 3 is low, and sufficient antistatic performance cannot be exhibited. However, if it is larger than 0.25 N / 25 mm, peeling from the adherend becomes difficult, such as a peeling step of the adhesive tape after back grinding. Moreover, it is more preferable that the adhesive force after ultraviolet curing is in the range of 0.15 to 0.23 N / 25 mm.
The ultraviolet curing referred to here is preferably cured by a high-pressure mercury lamp and cured at a dose of 200 mJ / cm ² , but is not limited thereto.

  The adhesive tape 1 for processing an antistatic semiconductor according to the present invention is bonded to a silicon mirror wafer, and the adhesive layer 3 is UV-cured after being peeled off by 90 degrees (according to JIS Z 0237; peeling speed is 50 mm) / Min) is in the range of 4-15% of the 90 degree peel-off adhesive strength before UV curing. It can be said that the greater the “adhesive strength after UV curing / adhesive strength before UV curing”, the smaller the change in flexibility of the molecular chain in the pressure-sensitive adhesive layer 3 due to UV curing. When it is 4% or more, the flexibility of the molecular chain in the pressure-sensitive adhesive layer 3 can be maintained even after ultraviolet curing, and sufficient antistatic performance can be obtained even after ultraviolet curing. However, if it is greater than 15%, the holding power before UV curing is insufficient, and the peeling step after UV curing becomes difficult. If it is less than 4%, sufficient antistatic performance cannot be obtained after UV curing. The ratio of the adhesive strength before and after UV curing is more preferably in the range of 6% to 13%.

  The thickness of the pressure-sensitive adhesive layer 3 of the antistatic semiconductor processing pressure-sensitive adhesive tape 1 of the present invention is preferably in the range of 20 to 250 μm, and more preferably in the range of 30 to 230 μm. If the pressure-sensitive adhesive layer 3 is thicker than 250 μm, it will be difficult to develop antistatic performance. Further, when the thickness is less than 20 μm, the followability becomes insufficient when bonding to the pattern surface, and water permeates during processing.

  Examples of the conductive polymer contained in the antistatic layer 5 include polythiophene, polypyrrole, polyaniline, and poly (p-phenylene vinylene). A polythiophene polymer is most preferable in terms of optical properties, appearance, antistatic effect, and stability during heating and humidification of the antistatic effect. The polythiophene-based polymer can be used as a water-soluble conductive polymer or a water-dispersible conductive polymer. Examples of the polythiophene polymer include polyethylene dioxythiophene, polythiophene, and polyethylene vinylene.

  By using a water-soluble conductive polymer or a water-dispersible conductive polymer, a coating solution (polymer composition) for forming the antistatic layer 5 can be prepared as an aqueous solution or a water-dispersed solution. There is no need to use a solvent. Therefore, the quality change and deterioration of the base film base material by an organic solvent can be suppressed. The aqueous solution or aqueous dispersion preferably contains only water as a solvent from the viewpoint of adhesion, but may contain a hydrophilic solvent. Examples of the hydrophilic solvent include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, and tert-amyl alcohol. And alcohols such as 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol.

The weight average molecular weight of the water-soluble or water-dispersible polythiophene in terms of polystyrene is preferably 400,000 or less, more preferably 300,000 or less. The water solubility of the water-soluble conductive polymer means that the solubility in 100 g of water is 5 g or more. The weight average molecular weight is a polystyrene-converted weight average obtained by measuring a 1% solution obtained by dissolving a polymer in tetrahydrofuran by gel permeation chromatography (trade name: 150-C ALC / GPC, manufactured by Waters). Calculated as molecular weight.
The solubility of the water-soluble conductive polymer in 100 g of water is preferably 20-30 g. A water-dispersible conductive polymer is a polythiophene resin dispersed in water in the form of fine particles. The aqueous dispersion has a low liquid viscosity and is easy to apply to a thin film. Is excellent. Here, the size of the polymer fine particles is preferably 1 μm or less from the viewpoint of the uniformity of the antistatic layer 5.

The polythiophene resin that is a water-soluble or water-dispersible conductive polymer preferably has a hydrophilic functional group in the molecule. Examples of hydrophilic functional groups include sulfone groups, amino groups, amide groups, imino groups, quaternary ammonium bases, hydroxyl groups, mercapto groups, hydrazino groups, carboxyl groups, sulfate ester groups, phosphate ester groups, or salts thereof. Etc. Having a hydrophilic functional group in the molecule makes it easy to dissolve in water or to be easily dispersed in water in the form of fine particles, so that the water-soluble conductive polymer or water-dispersible conductive polymer can be easily prepared. it can.
Examples of commercially available water-soluble polythiophene polymers include Conisol (manufactured by Inscontec Corporation).

The antistatic layer 5 preferably contains a binder component for the purpose of improving film formation and adhesion to the base film 7. When a water-soluble conductive polymer or a water-dispersible conductive polymer is used as the antistatic agent, it is preferable to use a water-soluble or water-dispersible binder component.
Examples of the binder component include polyurethane resin, polyester resin, acrylic resin, polyether resin, cellulose resin, polyvinyl alcohol resin, epoxy resin, polyvinyl pyrrolidone, polystyrene resin, polyethylene glycol, pentaerythritol, and the like. can give. Particularly preferred are polyurethane resins, polyester resins and acrylic resins. Further, as the binder component, a resin having an unsaturated double bond such as an acrylic oligomer (or polymer) or an acrylic urethane oligomer (or polymer) may be used.

  These binder components may be used alone or in combination of two or more as appropriate. Although the amount of the binder component used depends on the type of the conductive polymer, it is preferably 10 to 500 parts by weight, more preferably 50 to 400 parts by weight, particularly preferably 100 parts by weight of the conductive polymer. 100 to 300 parts by mass.

The surface resistivity of the antistatic layer 5 containing the conductive polymer is preferably 1 × 10 ¹² Ω / □ or less, more preferably 1 × 10 ¹¹ Ω / □ or less, and particularly preferably 1 × 10 ^9. Ω / □ or less.

  Ionic antistatic agents such as ion conductive polymers and ionic surfactants contain metal ions, but the antistatic layer 5 containing the conductive polymer does not contain metal ions, The adherend is not contaminated by metal ions. Further, since the antistatic layer 5 is formed on the base film 7 and the pressure-sensitive adhesive layer 3 is formed thereon, the antistatic layer 5 does not touch the adherend, and the antistatic layer 5 Thus, the adherend is not contaminated. Therefore, after peeling of the antistatic semiconductor processing pressure-sensitive adhesive tape, there is no adhesion of a microscopic level particle-like substance or an optically unobservable liquid substance to the adherend.

  The layer thickness of the antistatic layer 5 is preferably 0.01 μm to 0.7 μm from the viewpoint of antistatic performance. When the thickness is less than 0.01 μm, the antistatic performance is not effectively exhibited, and when the thickness is 0.7 μm or more, the conductivity is excessively improved and the semiconductor is destroyed by overcurrent. The layer thickness of the antistatic layer 5 is more preferably 0.1 μm to 0.6 μm.

The base film 7 used for the antistatic semiconductor processing pressure-sensitive adhesive tape of the present invention is mainly intended to protect against impacts when processing a semiconductor, and is particularly resistant to water washing and the like. It is important to have. Accordingly, as the base film, polyolefins such as polyethylene, polypropylene and polybutene, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid copolymers and ethylene- (meth) acrylic acid ester copolymers are used. Preferred are polymer materials such as ethylene copolymer, soft polyvinyl chloride, semi-rigid polyvinyl chloride, polyester, polyurethane, polyamide, polyimide, natural rubber and synthetic rubber. These are used as single-layer films or as respective multilayer films.
In addition, the base film 7 is preferably visible light transmissive, and in particular, when an ultraviolet curable material is used as the pressure-sensitive adhesive layer described later, the base film 7 is preferably ultraviolet transmissive.
The thickness of the base film 7 is not particularly limited, but is preferably 10 to 500 μm, more preferably 40 to 500 μm, and particularly preferably 70 to 250 μm.

  The antistatic semiconductor processing adhesive tape of the present invention is useful as an adhesive tape for protecting or dicing, for example, a substrate of silicon wafer, glass, ceramics, polymer, etc., when manufacturing electrical, electronic and semiconductor parts. . In particular, the antistatic semiconductor processing pressure-sensitive adhesive tape of the present invention can exhibit excellent antistatic performance after UV curing even when the pressure-sensitive adhesive layer is thick, and prevents water penetration during backgrinding, The adherend after UV curing has good peelability and is suitable for bonding to a surface on which a semiconductor circuit pattern having a thick adhesive layer for following unevenness is formed. In particular, it is suitable for processing a wafer with bumps having high unevenness.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, the performance test example is shown with a comparative example, and the outstanding effect of this invention is clarified, this invention is not limited to these.

(Synthesis of acrylic copolymer with photocurable unsaturated carbon bond in the molecule)
A copolymer was obtained by solution radical polymerization using 65 parts by mass of butyl acrylate, 25 parts by mass of 2-hydroxyethyl acrylate, and 10 parts by mass of acrylic acid. Next, an acrylic copolymer having a photocurable unsaturated carbon bond in the molecule was produced by dropping the isocyanate with 2-isocyanatoethyl methacrylate. The amount of photocurable unsaturated carbon bonds was appropriately adjusted by adding 2-isocyanatoethyl methacrylate dropwise and the reaction time of solution radical polymerization.

[Example 1]
A polyolefin film having a thickness of 100 μm is used as a base film, and an aqueous solution of polyethylene dioxythiophene (trade name: Conisol F-205, manufactured by Inscontec Co., Ltd.) is gravure coated on one main surface of the base film. Thus, an antistatic layer having a thickness of 0.1 μm was formed. Thereafter, the base polymer is an acrylic copolymer containing a photocurable unsaturated carbon bond in the molecule at a rate of 0.5 meq / g and a polyisocyanate compound as a curing agent (trade name Coronate L, manufactured by Nippon Polyurethane Co., Ltd.). And α-hydroxycyclohexyl phenyl ketone as a photoinitiator were blended in the blending ratios shown in Table 1 to prepare a pressure-sensitive adhesive coating solution. The pressure-sensitive adhesive coating solution was applied to a polyethylene terephthalate film (thickness 25 μm) that had been subjected to silicon release treatment using a comma coater at a linear speed of 2 m / min, and then passed through a hot air drying oven set at 110 ° C. Is formed and bonded to an antistatic treatment base film to produce an antistatic semiconductor processing pressure-sensitive adhesive tape (having the layer structure shown in FIG. 1) with a release film having a coating thickness after drying of 30 μm. did.

[Example 2]
An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer in Example 1 was changed to 100 μm.

Example 3
An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer in Example 1 was changed to 230 μm.

Example 4
An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 2 except that the curing agent and the photoinitiator in the pressure-sensitive adhesive layer of Example 2 were blended in the blending ratio shown in Table 1.

Example 5
An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 2 except that the curing agent and the photoinitiator in the pressure-sensitive adhesive layer of Example 2 were blended in the blending ratio shown in Table 1.

Example 6
An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the thickness of the antistatic layer in Example 1 was 0.4 μm.

Example 7
An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the thickness of the antistatic layer in Example 1 was 0.6 μm.

[Comparative Example 1]
An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer in Example 1 was changed to 10 μm.

[Comparative Example 2]
An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer in Example 1 was changed to 300 μm.

[Comparative Example 3]
Using an acrylic copolymer containing a photocurable unsaturated carbon bond at a ratio of 1.0 meq / g as the base polymer in the pressure-sensitive adhesive layer of Example 2, the mixing ratio shown in Table 1 for the curing agent and the photoinitiator An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 2 except that it was blended.

[Comparative Example 4]
Using an acrylic resin that does not contain a photocurable unsaturated carbon bond as a base polymer in the pressure-sensitive adhesive layer of Example 2, a polyfunctional oligomer containing a curing agent, a photoreaction initiator, and an ultraviolet curable unsaturated carbon bond is used. An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 2 except that the blending ratios shown in Table 1 were blended.

[Comparative Example 5]
An adhesive tape for antistatic semiconductor processing was produced in the same manner as in Example 2 except that the curing agent and the photoinitiator in the adhesive layer of Example 2 were blended in the blending ratio shown in Table 1.

[Comparative Example 6]
An adhesive tape for antistatic semiconductor processing was produced in the same manner as in Example 2 except that the curing agent and the photoinitiator in the adhesive layer of Example 2 were blended in the blending ratio shown in Table 1.

[Comparative Example 7]
The thickness of the antistatic layer of Example 1 was set to 0.75 μm, an acrylic resin not containing a photocurable unsaturated carbon bond was used as the base polymer in the pressure-sensitive adhesive layer, a curing agent, a photoreaction initiator, and an ultraviolet curing property. An antistatic semiconductor processing pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that a polyfunctional oligomer containing an unsaturated carbon bond was blended at a blending ratio shown in Table 1.

[Performance test of adhesive tape for antistatic semiconductor processing]
For each of the adhesive tapes obtained in the above examples and comparative examples, the surface resistivity, adhesive strength, water penetration prevention during back grinding, releasability after ultraviolet curing, and antistatic performance are determined by the following tests. As a result of evaluation, the results shown in Tables 2 and 3 were obtained.

(1) Surface resistivity measurement The voltage of 500V was applied using the resistance meter, the electric current value 60 seconds after the application was read, and the surface resistivity before and behind ultraviolet curing was measured. The ultraviolet curing was performed by irradiation with 200 mJ / cm ² with a high-pressure mercury lamp.

(2) Adhesive strength measurement Adhesive strength (exfoliation) before UV irradiation after peeling by 90 degrees in accordance with JIS Z0237 after laminating a 25 mm wide adhesive tape test piece to a silicon mirror wafer with a 2 kg load roller and leaving it to stand for 1 hour. The speed was 50 mm / min). Moreover, after ultraviolet curing and leaving it to stand for 1 hour, the adhesive force after ultraviolet curing was similarly measured. The ultraviolet curing was performed by irradiation with 200 mJ / cm ² with a high-pressure mercury lamp.

(3) Evaluation of water penetration prevention during backside grinding, peelability after UV curing, antistatic performance evaluation Adhesive tapes obtained in Examples and Comparative Examples on the surface of a silicon wafer (diameter: 6 inches, thickness: 625 μm) The surface of the semiconductor silicon wafer is ground until the thickness of the wafer becomes 100 μm while cooling with 23 ° C. water using a grinder, and water is applied between the adhesive tape and the silicon wafer. It was confirmed whether there was intrusion. Then, it was irradiated with 200 mJ / cm ² with a high-pressure mercury lamp, cured with ultraviolet rays, and evaluated whether the adhesive tape could be peeled without damaging the silicon wafer and whether the adhesive remained on the silicon wafer. A sample in which the silicon wafer was not damaged and the pressure-sensitive adhesive tape could be peeled off without leaving a pressure-sensitive adhesive was rated as “Good”. In addition, we confirmed whether the semiconductor was destroyed during processing due to static electricity and overcurrent, and evaluated antistatic performance.

The evaluation results of the examples are summarized in Table 2, and the evaluation results of the comparative examples are summarized in Table 3. The surface resistivity before UV curing was not significantly different between the example and the comparative example, but the surface resistivity after UV curing was greatly different, and the example had better performance than the comparative example. In the Examples, since the flexibility of the molecular chain of the pressure-sensitive adhesive layer is appropriately maintained even after UV curing, good antistatic performance is exhibited even after UV curing.
The pressure-sensitive adhesive composition of Comparative Example 1 was the same as in Examples 1 to 3, and did not break down the semiconductor and showed sufficient antistatic performance. However, because the pressure-sensitive adhesive layer was thin, the pressure-sensitive adhesive tape for semiconductor processing and silicon were used during backside grinding. Water has entered between the wafers.
Although the pressure-sensitive adhesive composition of Comparative Example 2 was the same as those of Examples 1 to 3, the pressure-sensitive adhesive layer was thick, so that it did not exhibit sufficient antistatic performance after UV curing, and the semiconductor was damaged by discharge.
Comparative Example 3 did not show sufficient antistatic performance after UV curing, and the semiconductor was broken by discharge. In Comparative Example 3, an acrylic resin containing an ultraviolet curable unsaturated carbon bond is used as the base polymer of the pressure-sensitive adhesive as in the example, but the ratio of the unsaturated carbon bond is larger than that of the base polymer of the example. Therefore, Comparative Example 2 has higher ultraviolet curability than the Examples, and the flexibility of the pressure-sensitive adhesive layer is lower than that of the Examples. As a result, the change in surface resistivity due to UV curing was large, and sufficient antistatic performance could not be obtained after UV curing. The fact that the flexibility of the pressure-sensitive adhesive layer after UV curing in Comparative Example 3 is lower than that of the Examples is understood from the fact that Comparative Example 3 has a lower adhesive strength after UV curing than the Examples. Further, the fact that the UV curable property of Comparative Example 3 is higher than that of the example is understood from the fact that “adhesive strength after UV curing / adhesive strength before UV curing” is small.
Similarly to Comparative Example 3, Comparative Example 4 did not exhibit sufficient antistatic performance after UV curing, and the semiconductor was broken by discharge. The base polymer of Comparative Example 4 does not have an ultraviolet curable unsaturated carbon bond, but includes an oligomer containing an unsaturated carbon bond. The oligomer containing an unsaturated carbon bond is polyfunctional, has a large number of blended parts, and has higher ultraviolet curability than the examples. Therefore, the surface resistivity after UV curing was larger than that of the example and the comparative example 3.
In Comparative Example 5, the antistatic performance after UV curing was good, but the adhesive strength after UV curing was high, so that the silicon wafer was damaged when the adhesive tape was peeled off after back grinding.
Comparative Example 6 had good antistatic performance after UV curing, and had good peelability unlike Comparative Example 5, but because the adhesive strength before UV curing was low, Water entered between the silicon wafers.
In Comparative Example 7, since the antistatic layer was thick, the surface resistivity before UV curing was low, the conductivity was too good, and the semiconductor was destroyed by overcurrent.

DESCRIPTION OF SYMBOLS 1 ......... Adhesive tape 3 ......... Adhesive layer 5 ......... Antistatic layer 7 ......... Base film 9 ......... Release liner

Claims (3)

An adhesive tape comprising a base film and a photocurable adhesive layer, wherein the base film contains an antistatic layer containing a conductive polymer on at least one surface, and a base polymer molecule on the antistatic layer. It has a pressure-sensitive adhesive layer containing a photocurable unsaturated carbon bond therein, and the surface resistivity on the pressure-sensitive adhesive layer side before and after ultraviolet curing is 1 × 10 ^{6 to} 5 × 10 ¹² Ω / □,
The pressure-sensitive adhesive layer has a thickness of 20 to 250 μm,
When the pressure-sensitive adhesive tape is bonded to a silicon mirror wafer, the pressure-sensitive adhesive layer is peeled off by 90 degrees after UV curing (according to JIS Z 0237; peeling speed is 50 mm / min), 0.15-0. An adhesive tape for antistatic semiconductor processing, characterized by being 25 N / 25 mm.   When the pressure-sensitive adhesive tape is bonded to a silicon mirror wafer, the pressure-sensitive adhesive layer is peeled off by 90 degrees after UV curing (according to JIS Z 0237; peeling speed is 50 mm / min), 90 degrees before UV curing. The adhesive tape for antistatic semiconductor processing according to claim 1, wherein the adhesive tape has an adhesive strength of 4 to 15% of the peel adhesive strength.   When the adhesive tape is bonded to a silicon mirror wafer, the adhesive layer is peeled off by 90 degrees before UV curing (according to JIS Z 0237; peeling speed is 50 mm / min) exceeding 1.4 N / 25 mm. The pressure-sensitive adhesive tape for processing an antistatic semiconductor according to claim 1 or 2.

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