JP4822885B2 - Adhesive sheet for semiconductor - Google Patents

Description

  The present invention relates to a re-peelable semiconductor adhesive sheet used for back grinding and dicing of a semiconductor wafer.

  Conventionally, various pressure-sensitive adhesive sheets are used in semiconductor manufacturing processes. Among them, a protective sheet used for protecting a wafer in a back grinding process of a semiconductor wafer, a fixing sheet used in a cutting / dividing (dicing) process into element pieces, etc. A “removable” pressure-sensitive adhesive sheet that is peeled again after the process is completed is used.

  These re-peelable pressure-sensitive adhesive sheets are required to have various characteristics. For example, the adhesive layer exhibits sufficient adhesion in the processing step, but is required to be easily peelable in the peeling step. In addition, the base film has a high degree of flexibility, as a protective sheet for back grinding, in order to prevent wafer damage due to the high pressure of the grinding wheel, and as a dicing sheet for the purpose of improving expandability during pickup recovery. Elasticity is required.

  Regarding the improvement of the above easy peelability, for example, a pressure sensitive adhesive sheet using a radiation curable pressure sensitive adhesive having at least two carbon-carbon double bonds in the molecule and exhibiting easy peelability is known. (For example, see Patent Document 1 and Patent Document 2). On the other hand, as the base film, a flexible polyvinyl chloride film is suitably used from the viewpoint of improving expandability and dicing properties.

  As a method of laminating the pressure-sensitive adhesive layer on the base film, generally, a direct irradiation method in which the pressure-sensitive adhesive layer is directly applied and dried, and a transfer method in which the pressure-sensitive adhesive is applied onto a release film called a separator and bonded together. However, when a radiation curable adhesive is provided on a polyvinyl chloride film, the former is mainly used. This is because the affinity between the acrylic resin generally used for the base polymer of the adhesive and the polyvinyl chloride resin of the base material is low, so that sufficient adhesion (throwing property) cannot be obtained by the transfer method. Because. However, in the case of the direct irradiation type, since the polyvinyl chloride film also receives heat in the coating liquid drying process, the tape quality may be deteriorated such as variation in the thickness of the tape due to thermal deformation.

  For this reason, it has been eagerly desired to improve the anchoring property of the radiation curable pressure-sensitive adhesive to the polyvinyl chloride film. For example, by utilizing the affinity between the urethane resin and the nitrogen atom, a co-polymer consisting of the vinyl chloride resin and the urethane resin is desired. A pressure-sensitive adhesive sheet in which an acrylic resin pressure-sensitive adhesive containing a nitrogen atom is laminated on a polymer resin sheet to improve anchoring properties is known (for example, see Patent Document 3).

  However, in the above technology, the copolymerization amount of the urethane resin with respect to the vinyl chloride resin is regulated, so that the physical properties of the base film such as flexibility are changed or restricted. The current situation is that there are still issues such as the level is still insufficient.

JP-A-60-196956 JP 60-223139 A JP-A-11-302607

  The object of the present invention is a pressure-sensitive adhesive sheet that exhibits excellent removability and high expandability, and is excellent in anchoring properties of the pressure-sensitive adhesive layer and the base film. The object is to provide an excellent pressure-sensitive adhesive sheet for semiconductors with little peeling.

  As a result of intensive studies to achieve the above object, the present inventors have provided a radiation-curable acrylic pressure-sensitive adhesive layer on a polyvinyl chloride film via an acrylic resin layer containing nitrogen atoms. The present invention was completed by finding that the adhesion between the polyvinyl chloride film and the acrylic pressure-sensitive adhesive layer was dramatically improved.

That is, the present invention provides an intermediate layer (B layer) containing an acrylic resin containing a nitrogen atom in the molecule on at least one side of a base film (A layer) mainly composed of a soft polyvinyl chloride resin, and an acrylic Content of nitrogen atom-containing monomer unit of acrylic resin having radiation curing type pressure-sensitive adhesive layer (C layer) containing resin and radiation polymerization initiator in the order of A layer / B layer / C layer. There Ri der least 15 wt%, more carbon in the molecule to the B layer - providing a semiconductor pressure-sensitive adhesive sheet characterized by containing a radiation-polymerizable monomer or oligomer having a carbon-carbon double bond.

  Furthermore, this invention provides the said adhesive sheet for semiconductors which contains the radiation polymerizable monomer or oligomer which has a carbon-carbon double bond in a molecule | numerator in the said C layer.

  Furthermore, this invention provides the said adhesive sheet for semiconductors whose acrylic resin of the said C layer is an acrylic resin which has 1% or more of the side chain containing a carbon-carbon double bond of all the side chains.

  Furthermore, this invention provides the said adhesive sheet for semiconductors whose content of the radiation polymerization initiator in the said B layer is less than 0.01 weight%.

  Furthermore, this invention provides the said adhesive sheet for semiconductors with which the said B layer and C layer were produced by the transfer method.

  The pressure-sensitive adhesive sheet for semiconductors of the present invention can use a normal polyvinyl chloride base film, so that physical properties such as expandability and pick-up properties can be easily controlled, and the anchoring properties of the pressure-sensitive adhesive layer and the base film are excellent. In the manufacturing and processing steps and use, the adhesive layer is not peeled off and the adhesive residue on the adherend is not generated, so that productivity is improved and industrially beneficial.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the pressure-sensitive adhesive sheet for semiconductor of the present invention. In the semiconductor pressure-sensitive adhesive sheet 1 shown in FIG. 1, an intermediate layer 12, a radiation curable pressure-sensitive adhesive layer 13, and a release film 14 are provided on at least one surface of a base film 11.

  The semiconductor pressure-sensitive adhesive sheet according to the present invention comprises at least a base film (referred to as A layer), an intermediate layer (referred to as B layer), and a radiation curable pressure-sensitive adhesive layer (C layer) as A layer / B layer / C layer. The three-layer laminated structure. The effect of the present invention cannot be obtained in the two-layer laminated structure of A layer / C layer. In addition, the film layer other than said A layer, B layer, and C layer may be provided in the range which does not inhibit the effect of this invention. In particular, it is preferable that a release film (or a release resin layer) is further provided from the viewpoint of preventing contamination of the pressure-sensitive adhesive sheet surface and blocking during storage, in which case A layer / B layer / C Layer / release film (release resin layer), release film (release resin layer) / A layer / B layer / C layer, release film (release resin layer) / A layer / B layer / C layer / A laminated structure of a release film (release resin layer) is preferable. The most preferable laminated structure is A layer / B layer / C layer / release film (release resin layer).

  A layer used for the adhesive sheet for semiconductors of this invention has a polyvinyl chloride resin as a main component. The term “main component” as used herein means that the content in the layer is 50% by weight or more, preferably 70% by weight or more, and most preferably 80% by weight or more.

  The polyvinyl chloride resin of the present invention is preferably soft polyvinyl chloride. The soft polyvinyl chloride may include a plasticizer, or may be a copolymer or a polymer alloy. Use of flexible soft polyvinyl chloride as the base film is preferable because high expandability can be obtained and wafer breakage can be prevented in the dicing process.

  Preferred examples of the plasticizer include phthalic acid esters such as dibutyl phthalate, dioctyl phthalate, dinonyl phthalate and diisodecyl phthalate, other polyester plasticizers, epoxy plasticizers such as epoxidized soybean oil, and trimet plasticizers. . When adding a plasticizer, 20-40 weight% is preferable with respect to the mass of the whole A layer, More preferably, it is 25-35 weight%. When the addition amount of the plasticizer is less than 20% by weight, the polyvinyl chloride resin becomes hard and the expandability may be lowered. When it exceeds 40% by weight, the plasticizer is present on the surface of the adhesive sheet. They may bleed and adhere to the semiconductor wafer, causing contamination.

  Examples of the copolymer include vinyl chloride copolymers such as urethane-vinyl chloride copolymer, ethylene-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer, and ethylene-vinyl acetate copolymer. These copolymers may be used alone or as a mixture of two or more or other resins and elastomers. In addition to the block copolymer and random copolymer, the above-mentioned copolymer naturally includes a graft copolymer. Moreover, the said mixture contains not only a mere blend but the alloy which has a chemical bond.

  Furthermore, the layer A of the present invention may contain other stabilizers, lubricants, and processing aids as long as the effects of the present invention are not impaired.

  The thickness of the A layer of the present invention is not particularly limited, but is usually 50 to 250 μm, and preferably 70 to 230 μm.

  Moreover, since a radiation is irradiated to an adhesive layer after a dicing process, what has sufficient radiolucency for the A layer of this invention is preferable. For example, the light transmittance at a wavelength of 365 nm is preferably 50% or more.

  B layer of this invention contains the acrylic resin which contains a nitrogen atom in a molecule | numerator as an essential component. As for content of the said acrylic resin, 70 weight% or more is preferable with respect to the whole B layer, More preferably, it is 80 weight% or more. The acrylic resin containing a nitrogen atom in the molecule is an acrylic resin containing a monomer component having a nitrogen atom as an essential component.

  Examples of the monomer component containing a nitrogen atom include (meth) acrylamide, (meth) acrylic acid N-hydroxymethylamide, (meth) acrylic acid alkylaminoalkyl ester (for example, dimethylaminoethyl methacrylate, t-butylamino). Ethyl methacrylate, etc.), N-vinylpyrrolidone, acryloylmorpholine, acrylonitrile, N, N-dimethylacrylamide and the like. In addition, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester, and (meth) of the present invention has the same meaning. The content of the monomer component containing nitrogen atoms is preferably 5% by weight or more, more preferably 10% by weight or more, and most preferably 15% by weight or more of the entire acrylic resin of the B layer. When the content of the monomer component containing nitrogen atoms is less than 5% by weight, the adhesion (throwing property) between the polyvinyl chloride base film and the pressure-sensitive adhesive layer is reduced, and the manufacturing / processing process or use The adhesive layer may peel or fall. In addition, adhesive residue may occur on the adherend during peeling from the adherend.

  It does not specifically limit as monomer components other than the monomer component containing a nitrogen atom, It is possible to use a well-known acrylic monomer component. Among these, from the viewpoints of affinity with the C layer, heat resistance, cohesive strength, adhesive improvement, etc., it is preferably exemplified that it is composed of (meth) acrylic acid alkyl ester and, if necessary, other copolymer components. Is done. Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, ( (Meth) isononyl acrylate and the like. Only one (meth) acrylic acid alkyl ester may be used, or two or more may be used as a copolymer. Other copolymer components include hydroxyalkyl esters of (meth) acrylic acid (eg, hydroxyethyl ester, hydroxybutyl ester, hydroxyhexyl ester, etc.), (meth) acrylic acid glycidyl ester, (meth) acrylic acid, itaconic acid , Maleic anhydride, vinyl acetate, styrene and the like. One or two or more copolymerization components can be used. Furthermore, if necessary, a polyfunctional monomer or the like may be included as a copolymerization component for crosslinking.

  The weight average molecular weight of the acrylic resin of the B layer of the present invention is preferably 500,000 to 2,000,000, more preferably 800,000 to 1,500,000 from the viewpoint of cohesive strength.

  B layer of this invention may contain a crosslinking agent in order to raise number average molecular weights, such as an acrylic resin which is a base polymer. Examples of the crosslinking agent include polyisocyanate compounds, epoxy compounds, aziridine compounds, melamine resins, urea resins, anhydrous compounds, polyamines, and carboxyl group-containing polymers. Among these, when a polyisocyanate compound is contained, an effect of improving anchoring property is obtained, which is preferable. As for the addition amount of a crosslinking agent, 0.01-100 weight part is preferable with respect to 100 weight part of acrylic resins.

  In the B layer of the present invention, a radiation-polymerizable monomer or oligomer containing a carbon-carbon double bond in the molecule (hereinafter, also referred to as a radiation-polymerizable compound) in order to ensure anchorage with the C-layer after radiation curing. Preferably). Examples of the radiation-polymerizable compound include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol (meth) acrylate, neopentyl glycol diester. (Meth) acrylate, esterified product of (meth) acrylic acid and polyhydric alcohol such as dipentaerythritol hexa (meth) acrylate; ester acrylate oligomer; 2-propenyl-3-butenyl cyanurate, tris (2-methacryloxyethyl ) Isocyanurates such as isocyanurates or isocyanurate compounds. These radiation polymerizable compounds may be used alone or in combination of two or more. Although it does not specifically limit as addition amount, 1-50 weight part is preferable with respect to an acrylic resin, and 5-20 weight part is further more preferable. When the addition amount is less than 1 part by weight, the effect of obtaining anchoring property after radiation curing is small, and when it exceeds 50 parts by weight, curing by radiation irradiation proceeds excessively, and anchoring property for the A layer is lowered. There is a case.

  It is preferable not to add a photopolymerization initiator to the B layer of the present invention. In this case, the content of the photopolymerization initiator in the entire B layer is preferably less than 0.05% by weight, more preferably less than 0.01% by weight, based on the total mass of the B layer. is there. Even when no photopolymerization initiator is added to the B layer, a part of the photopolymerization initiator added to the C layer diffuses and moves into the B layer, so that some photopolymerization initiator exists in the B layer. It becomes. However, most of the above diffusion is to the vicinity of the B layer / C layer interface and does not diffuse to the inside of the B layer (A layer side). For this reason, the photopolymerization initiator in the B layer is localized near the interface with the C layer. When radiation is applied in this state, the resin component of the B layer and the C layer undergoes a cross-linking reaction in the vicinity of the interface between the B layer and the C layer, resulting in a chemical bond. To do. On the other hand, since there is no photopolymerization initiator on the side of the polyvinyl chloride resin (A layer), the B layer hardly cures, and the affinity with the A layer and the anchoring property are maintained. When a photopolymerization initiator is added to the B layer and the content of the photopolymerization initiator is 0.05% by weight or more, the entire B layer is cured by radiation. The affinity with the vinyl resin may decrease, and the anchoring properties of the A layer and the B layer may decrease.

  Although the thickness of B layer of this invention is not specifically limited, 1-20 micrometers is preferable, More preferably, it is 3-10 micrometers.

  Furthermore, the B layer of the present invention may contain an antistatic agent within the range not impairing the effects of the present invention, if necessary. Moreover, you may contain conventional additives, such as various well-known anti-aging agent, a filler, and a coloring agent.

  C layer of this invention contains the base polymer which consists of an acrylic resin, and a photoinitiator as an essential component.

  The acrylic resin used in the C layer of the present invention is not particularly limited, and known ones can be used. For example, one or more (meth) acrylic acid alkyl esters are monomers. A polymer used as a component, or a copolymer obtained by copolymerizing one or more copolymer components for the purpose of modifying adhesiveness, cohesive force, heat resistance, etc., if necessary. The (meth) acrylic acid alkyl ester and copolymer component of the layer can be selected from the (meth) acrylic acid alkyl ester and copolymer components exemplified as the components preferably used for the B layer. In addition, if necessary, methoxyethyl (meth) acrylate, ethoxy (meth) acrylate, or the above-mentioned monomer containing nitrogen atoms may be used as a monomer component.

  The weight average molecular weight of the acrylic resin of the C layer of the present invention is preferably 500,000 or more, more preferably 800,000 to 3,000,000, from the viewpoint of reducing the low molecular weight body. The C layer preferably has a low content of low molecular weight substances from the viewpoint of preventing transfer contamination of a semiconductor wafer or the like. Specifically, the content of the low molecular weight substance having a molecular weight of 100,000 or less is preferably 10% by weight or less, more preferably 5% by weight or less, based on the total resin amount of the C layer.

  Further, a cross-linking agent may be added to the C layer in order to increase the number average molecular weight of an acrylic resin or the like. The crosslinking agent can be selected from a polyisocyanate compound, an epoxy compound, an aziridine compound, a melamine resin, a urea resin, an anhydrous compound, a polyamine, a carboxyl group-containing polymer, and the like, as in the case of the B layer. The addition amount of the crosslinking agent in the C layer is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the acrylic resin of the C layer from the viewpoint of adhesive strength.

  The C layer of the present invention is a radiation curable pressure-sensitive adhesive layer that is cured by ultraviolet rays, electron beams, or the like. By adopting a radiation curable type, for example, when dicing, the chip is prevented from peeling due to high adhesiveness, while at the time of pick-up, the adhesive strength is lost due to ultraviolet curing, and the peelability from the chip is improved.

  The C layer of the present invention is not particularly limited as long as it has a radiation-curable functional group such as a carbon-carbon double bond and exhibits adhesiveness. It is preferable to contain a radiation polymerizable compound (monomer or oligomer) containing a heavy bond in the molecule. Examples of the radiation polymerization compound include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol (meth) acrylate, neopentyl glycol diester. (Meth) acrylate, esterified product of (meth) acrylic acid and polyhydric alcohol such as dipentaerythritol hexa (meth) acrylate; ester acrylate oligomer; 2-propenyl-3-butenyl cyanurate, tris (2-methacryloxyethyl ) Isocyanurates such as isocyanurates or isocyanurate compounds. These radiation polymerization compounds may be used alone or in combination of two or more. Especially, when the radiation polymerization compound used for B layer and C layer is the same, a crosslinking reaction advances at the interface of B layer / C layer at the time of radiation irradiation, and it is preferable. Although the addition amount of the radiation polymerization compound is not particularly limited, it is preferably 20 to 75% by weight, particularly preferably 40 to 70% by weight, based on the entire C layer, from the viewpoint of removability after picking up radiation (pickup property). is there.

  In addition, as the C layer, an acrylic resin having a carbon-carbon double bond in the side chain, main chain or main chain terminal instead of or in addition to the addition of the radiation polymerizable compound. You may mix and use as a base polymer. For example, a (meth) acrylic acid alkyl ester copolymer having a carbon-carbon double bond in the molecule is obtained by introducing a carbon-carbon double bond into the above-described (meth) acrylic acid alkyl ester copolymer. can get. There are various known methods for preparing this, but from the viewpoint of ease of molecular design, after copolymerizing a monomer having a functional group with the polymer in advance, the other functional group capable of undergoing an addition reaction with this functional group. A method is preferred in which a group and a monomer having a carbon-carbon double bond are subjected to an addition reaction while maintaining the carbon-carbon double bond. Examples of the combination of the functional group on the acrylic polymer side and the functional group on the monomer side having a carbon-carbon double bond include a carboxylic acid group and an epoxy group or an aziridyl group, and a hydroxyl group and an isocyanate group. Among these, a combination using a hydroxyl group on the acrylic polymer side and an isocyanate group on the monomer side is particularly preferable because of easy reaction tracking. Examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate and 2-methacryloyloxyethyl isocyanate. Examples of the acrylic polymer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate, 2 Examples include polymers having monomer units of -hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like. When it has a carbon-carbon double bond in the side chain of the acrylic resin, it is preferable that 1% or more of all side chains (total number of side chains) have a carbon-carbon double bond, more preferably 3% or more. It is. When the carbon-carbon double bond is less than 1% of the total side chain, the effect of introducing the carbon-carbon double bond into the side chain is small.

  The C layer of the present invention contains a photopolymerization initiator. Examples of the photopolymerization initiator include benzoin alkyl ethers such as benzoin methyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; aromatic ketones such as benzyl, benzoin, benzophenone, and α-hydroxycyclohexyl phenyl ketone; Aromatic ketals such as benzyldimethyl ketal; thioxanthones such as polyvinylbenzophenone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, and diethylthioxanthone. Although the addition amount of a photoinitiator is not specifically limited, 0.1-10 weight part is preferable with respect to 100 weight part of acrylic resin which comprises C layer, More preferably, it is 0.5-5 weight part. is there. When the addition amount of the photopolymerization initiator is less than 0.1% by weight, the removability by irradiation with radiation may be insufficient. In addition, when the addition amount exceeds 5% by weight, the photopolymerization initiator bleeds on the surface of the C layer, which causes transfer contamination of the semiconductor wafer, or the photopolymerization initiator penetrates deep into the B layer. When diffused, the throwing ability of the A layer and the B layer may be lowered.

  Although the thickness of C layer is not specifically limited, 1-20 micrometers is preferable, More preferably, it is 3-10 micrometers.

  It should be noted that the layer C of the present invention may be applied to conventional additives such as various conventionally known tackifiers, anti-aging agents, fillers, colorants and the like within a range that does not impair the effects of the present invention. May be included.

  The pressure-sensitive adhesive sheet of the present invention is provided with a release film (separator) as necessary for the purpose of protecting the pressure-sensitive adhesive layer, for labeling, or for the purpose of smoothing the pressure-sensitive adhesive. It may be done. Although it does not specifically limit as a constituent material of a release film, Synthetic resin films, such as paper, polyethylene, a polypropylene, a polyethylene terephthalate, etc. are mentioned. In order to improve the peelability from the pressure-sensitive adhesive layer, the surface of the release film may be subjected to a peeling treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment as necessary. Moreover, the ultraviolet-ray prevention process may be performed as needed so that an adhesive sheet may not react with environmental ultraviolet rays. Although the thickness of a release film is not specifically limited, For example, 10-200 micrometers is preferable, More preferably, it is 25-100 micrometers.

  The shape of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, and can take any shape such as a tape shape and a label shape.

  Although the example of the manufacturing method of the adhesive sheet of this invention is demonstrated below, a manufacturing method is not limited to this.

[Base film (A layer)]
The polyvinyl chloride film used for the A layer of the present invention can be produced using a polyvinyl chloride resin polymerized using an existing polymerization method such as an ethylene dechlorination method or an oxychlorination method. If necessary, the polyvinyl chloride resin and a plasticizer, a stabilizer, a lubricant, and the like are kneaded with a Banbury mixer, a mixing roll, or a uniaxial or biaxial extruder to obtain a polymer. For forming a polymer sheet, a calendar method, a T-die method, a tube method or the like can be used. Moreover, you may use a commercially available polyvinyl chloride film.

[Acrylic resin composition (B layer, C layer)]
The acrylic resin forming the B layer and the C layer of the present invention is obtained by polymerization of a single monomer component or two or more monomer components. As the polymerization method, known polymerization methods such as a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, and a suspension polymerization method can be used. From the viewpoint of ease of application to the film, for example, solution polymerization can be used. Dissolve the main monomer component and copolymerization monomer component in a predetermined amount of a solvent such as toluene, and copolymerize at 55 to 65 ° C. for 5 to 10 hours depending on the type of monomer, and add a radiation polymerization compound and a crosslinking agent. In the case of the C layer resin, a photopolymerization initiator is added to obtain an acrylic resin composition solution.

[Lamination of B layer and C layer]
When laminating the B layer on the A layer, in order to improve the thickness accuracy, it is necessary to use a transfer method in which the intermediate layer solution is applied and dried in advance on the release film and then bonded to the polyvinyl chloride film. preferable. In the transfer method, since the polyvinyl chloride film does not pass through the drying step, it is preferable that deformation due to heat hardly occurs. However, it is not necessarily limited to this, and generally known methods such as co-extrusion, extrusion lamination, thermal lamination, dry lamination, and solution casting can be used.
Similarly, when the C layer is laminated on the B layer, it is preferable to use the transfer method. For example, from the two-layer laminated film of A layer / B layer obtained above, the release film is peeled off and the C layer is bonded in the same manner as the B layer, so that three layers of A layer / B layer / C layer are obtained. A laminated adhesive sheet is obtained.

[Methods for measuring physical properties and methods for evaluating effects]
Below, the measuring method used by this application and the evaluation method of an effect are illustrated.

(1) 90 degree peeling adhesive force The adhesive sheet for semiconductor obtained by the Example and the comparative example was cut | disconnected in the strip shape of length 150mm x width 25mm, and the sample piece was produced. The longitudinal direction of the sheet (the longitudinal direction of the original vinyl chloride film, or the longitudinal direction of the tape in the case of a tape-like adhesive sheet sample) was defined as the length direction of the sample, and the direction perpendicular thereto and the width direction of the sample.
The sample piece was attached to a mirror-treated silicon wafer (manufactured by Shin-Etsu Semiconductor Co., Ltd., trade name “CZN <100> 2.5-3.5”, diameter 4 inches) at 23 ° C. (room temperature). (Note that the release film was attached after being peeled off.) The attached portion was 80 mm long × 25 mm wide. A sample that was allowed to stand for 30 minutes in an unloaded, room temperature atmosphere was used as a sample before irradiation.
Moreover, the ultraviolet rays were irradiated to the same sample from the sheet | seat back surface (base film side) on the following conditions, and it was set as the sample after radiation irradiation.
Light source: High-pressure mercury lamp irradiation intensity: 50 mW / cm ² (Measuring instrument: “Ultraviolet illuminance meter UT-101” manufactured by USHIO)
Irradiation time: 10 seconds Irradiation energy: 500 mJ / cm ²
The above-mentioned sample before irradiation and sample after irradiation were subjected to a 90 ° peeling test under the following conditions in accordance with JIS Z 0237, and the peeling adhesive strength (unit: N / 25 mm) was measured.
Number of repeated tests: 3
Temperature: 23 ° C
Peel angle: 90 °
Tensile speed: 300 mm / min Initial length (chuck interval): 150 mm

(2) Adhesive residue The silicon wafer after the test of (1) was visually observed, and no residue (adhesive residue) of the adhesive layer or the laminate of the adhesive layer and the intermediate layer was confirmed on the silicon wafer. The product was judged as good (◯), the case where some adhesive residue was observed was insufficient (Δ), and the case where adhesive residue was observed on the entire surface was judged as poor (×).

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
(Preparation of layer B composition solution)
80 parts by weight of butyl acrylate, 20 parts by weight of acrylonitrile and 2 parts by weight of acrylic acid were copolymerized in a conventional manner in ethyl acetate to obtain an acrylic resin having a weight average molecular weight of 800,000. For 100 parts by weight of this acrylic resin (resin component), a UV-curable urethane acrylate oligomer (UV-curable oligomer obtained by reacting pentaerythritol triacrylate and diisocyanate as a radiation polymerizable oligomer: viscosity 1 Pa · S (60 ° C.), 20 parts by weight of a weight average molecular weight 2000) and 2 parts by weight of a polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd., trade name “Coronate L”) were added as a crosslinking agent to obtain a B layer composition solution.
(Preparation of C-layer composition solution)
50 parts by weight of methyl acrylate, 50 parts by weight of 2-ethylhexyl acrylate, and 5 parts by weight of acrylic acid were copolymerized in an ordinary manner in ethyl acetate to obtain an acrylic resin having a weight average molecular weight of 1,000,000. With respect to 100 parts by weight of this acrylic resin (resin component), 2,2-dimethoxy-1,2-diphenylethane-1-one (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name “ "Irgacure 651", 3 parts by weight of a molar extinction coefficient at a light wavelength of 365 nm of 150 mol ^-1 · cm ^-1 and a maximum absorption wavelength on the long wavelength side of 400 nm), a UV curable urethane acrylate oligomer (in the B layer) as a radiation polymerizable oligomer 60 parts by weight of the same as used) and 2 parts by weight of a polyisocyanate compound (trade name “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.) were added to obtain a C layer composition solution.
(Preparation of adhesive sheet)
Release side of polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., trade name “Diafoil MRN”, film thickness 38 μm) that has been subjected to release treatment made of silicone as a release film The B layer composition solution was applied to the surface of the film and dried at 140 ° C. for 5 minutes to prepare a B layer on the release film. B layer thickness was 5 micrometers. Next, the release film on which the B layer is formed is bonded to a soft polyvinyl chloride film (film thickness 100 μm) using a roller so that the B layer is in contact, and the B layer is placed on the polyvinyl chloride film (A layer). Was formed by a transfer method to obtain a laminated sheet of A layer / B layer. The release film is further laminated on the surface of the laminated sheet on the B layer side.
Next, in the same manner as described above, the C layer composition solution was applied and dried on the release PET film to prepare a C layer on the release film. C layer thickness was 5 micrometers.
Furthermore, after peeling off the release film from the laminate sheet of the above A layer / B layer, the release film having the above C layer is placed on the B layer of the laminate sheet, and the C layer and the B layer are transferred by a roller. The adhesive sheet for semiconductor was obtained by bonding so as to be in contact with each other.
As shown in Table 1, the obtained pressure-sensitive adhesive sheet was a pressure-sensitive adhesive sheet that exhibited good removability upon irradiation with radiation and had little adhesive residue when peeled off, and had excellent anchoring properties.

Example 2
(Preparation of layer B composition solution)
70 parts by weight of 2-ethylhexyl acrylate, 30 parts by weight of acryloylmorpholine and 2 parts by weight of acrylic acid were copolymerized in an ordinary manner in ethyl acetate to obtain an acrylic resin having a weight average molecular weight of 900,000. To 100 parts by weight of this acrylic resin, 20 parts by weight of a UV curable urethane acrylate oligomer (same as Example 1) and 2 parts by weight of a polyisocyanate compound (trade name “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.) are added. A layer B composition solution was obtained.
(Preparation of C-layer composition solution)
50 parts by weight of methyl acrylate, 50 parts by weight of 2-ethylhexyl acrylate and 5 parts by weight of 2-hydroxyethyl acrylate were copolymerized in a conventional manner in ethyl acetate, and 2-hydroxy in the obtained polymer was further obtained. 90% of the side chain terminal OH groups of ethyl acrylate were subjected to an addition reaction of the NCO group of 2-methacryloyloxyethylene isocyanate to obtain an acrylic resin having a weight-average molecular weight of 500,000 having a carbon-carbon double bond at the terminal. In addition, the ratio of the side chain containing a carbon-carbon double bond with respect to all the side chains of an acrylic resin was 4.3%.
2,2-dimethoxy-1,2-diphenylethane-1-one (trade name “Irgacure 651” manufactured by Ciba Specialty Chemicals Co., Ltd.) is used as a photopolymerization initiator for 100 parts by weight of the acrylic resin. 3 parts by weight, 2 parts by weight of a melamine-based crosslinking agent, 30 parts by weight of a UV curable urethane acrylate oligomer (same as in Example 1), and a polyisocyanate compound (trade name “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.) 2 Part by weight was added to obtain a C layer composition solution.
(Preparation of adhesive sheet)
Using the above-mentioned B layer composition solution and C layer composition solution, the other conditions such as the base film were exactly the same as in Example 1, and a semiconductor pressure-sensitive adhesive sheet was obtained using the transfer method.
As shown in Table 1, the obtained pressure-sensitive adhesive sheet was a pressure-sensitive adhesive sheet that exhibited good removability upon irradiation with radiation and had little adhesive residue when peeled off, and had excellent anchoring properties.

Comparative Example 1
(Preparation of layer B composition solution)
50 parts by weight of butyl acrylate, 50 parts by weight of 2-ethylhexyl acrylate, and 2 parts by weight of acrylic acid were copolymerized in an ordinary manner in ethyl acetate to obtain an acrylic resin having a weight average molecular weight of 800,000. 2 parts by weight of a polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd., trade name “Coronate L”) was added to 100 parts by weight of this acrylic resin to obtain a B layer composition solution.
Using the above-mentioned B layer composition solution, the other conditions such as the C layer composition and the base film were exactly the same as in Example 1, and a semiconductor pressure-sensitive adhesive sheet was obtained using the transfer method.
As shown in Table 1, the obtained pressure-sensitive adhesive sheet was a pressure-sensitive adhesive sheet in which adhesive residue was observed at the time of peeling and the anchoring property was inferior.

Comparative Example 2
A semiconductor pressure-sensitive adhesive sheet was obtained using the transfer method in exactly the same manner as in Example 2 except that the B layer was not provided.
As shown in Table 1, the obtained pressure-sensitive adhesive sheet was a pressure-sensitive adhesive sheet in which adhesive residue was observed at the time of peeling and the anchoring property was inferior.

  From the examples and comparative examples, the adhesive sheet having an intermediate layer made of an acrylic resin containing a nitrogen atom according to the present invention did not generate adhesive residue at the time of peeling, and was evaluated well. In the case of the pressure-sensitive adhesive sheet having no intermediate layer made of an acrylic resin containing a nitrogen atom as shown in the comparative example, the anchoring property was poor, the adhesive residue was generated, and the practicality was inferior.

It is a schematic sectional drawing which shows an example of the adhesive sheet for re-peeling of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adhesive sheet for semiconductor wafers 11 Base film (A layer)
12 Intermediate layer (B layer)
13 Radiation curable adhesive layer (C layer)
14 Release film

Claims (5)

An intermediate layer (B layer) containing an acrylic resin containing a nitrogen atom in the molecule on at least one side of a base film (A layer) comprising a soft polyvinyl chloride resin as a main component, and an acrylic resin and a radiation polymerization initiator A radiation curable pressure-sensitive adhesive layer (C layer) containing A in the order of A layer / B layer / C layer, and the content of the nitrogen atom-containing monomer unit of the acrylic resin constituting the B layer is 15% by weight or more Ah is, further carbon atoms in the molecule in the layer B - semiconductor pressure-sensitive adhesive sheet characterized by containing a radiation-polymerizable monomer or oligomer having a carbon-carbon double bond. The pressure-sensitive adhesive sheet for a semiconductor according to claim 1, wherein the layer C contains a radiation-polymerizable monomer or oligomer having a carbon-carbon double bond in the molecule. The adhesive sheet for semiconductors of Claim 1 or Claim 2 whose acrylic resin of C layer is an acrylic resin which has 1% or more of the side chain containing a carbon-carbon double bond of all the side chains. Content of the radiation polymerization initiator in the said B layer is less than 0.01 weight%, The adhesive sheet for semiconductors in any one of Claims 1-3. The pressure-sensitive adhesive sheet for semiconductor according to claim 1, wherein the B layer and the C layer are produced by a transfer method.

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