JP2005116610A - Semiconductor wafer processing method and semiconductor wafer processing adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor wafer processing method capable of thinly processing a semiconductor wafer having a wiring pattern or bump having a large unevenness formed on the surface without causing damage or warping.
A method for processing a semiconductor wafer includes processing a semiconductor wafer by performing a thin processing on a semiconductor wafer having a wiring pattern and / or a bump having a maximum unevenness of 0.1 to 350 μm formed on a surface. A method is characterized in that a semiconductor wafer is fixed to a support via an adhesive sheet and subjected to thin processing. The pressure-sensitive adhesive sheet has a pressure-sensitive adhesive surface to be bonded to the semiconductor wafer, and reduces the adhesive force to the semiconductor wafer on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet bonded to the semiconductor wafer after thin processing of the semiconductor wafer. It is preferable to have a configuration capable of. Moreover, the adhesive layer used as the adhesive surface of the adhesive sheet bonded together to a semiconductor wafer may be formed through the intermediate | middle layer.
[Selection figure] None

Description

  The present invention relates to a method for processing a semiconductor wafer and an adhesive sheet for processing a semiconductor wafer, and more specifically, a method for processing a semiconductor wafer by subjecting the semiconductor wafer to thin processing without causing damage or warpage, and the semiconductor The present invention relates to an adhesive sheet for processing a semiconductor wafer used for thin processing of a wafer.

  When a semiconductor integrated circuit such as an IC card or a thin film transistor is manufactured, the thickness of the semiconductor wafer serving as the substrate can be reduced to reduce the size of the device having the semiconductor integrated circuit or the semiconductor wafer. The degree of freedom can be improved. In addition, since IC cards and the like are desired to be thin and have a large chip, the size of semiconductor wafers has been increased from 6 inches to 8 inches or 12 inches.

  In particular, in a very large semiconductor wafer such as 12 inches, when the semiconductor wafer is thinned to 100 μm or less, there is a problem that the semiconductor wafer is damaged due to the strength reduction of the semiconductor wafer, or the semiconductor wafer itself is thin and fragile. In addition, since the surface of the semiconductor wafer is uneven due to a wiring pattern (circuit pattern) or the like, there is a problem that the semiconductor wafer is warped and easily damaged even by a slight external force. Therefore, the strength of the semiconductor wafer has been increased by attaching an adhesive tape or sheet as a protective support tape or sheet to the surface of the semiconductor wafer on which the wiring pattern is formed (see Patent Documents 1 to 3).

Japanese Patent Laid-Open No. 5-1666692 JP-A-7-242860 JP 2000-355678 A

  In recent years, along with the increase in device form of semiconductor chips and higher performance of devices, semiconductor wafers such as silicon-based semiconductor wafers and semiconductor wafers such as gallium-arsenic-based semiconductor wafers have large unevenness in the surface wiring pattern, Investigation of a semiconductor wafer (bump wafer) provided with bumps of about 20 to 100 μm is underway. In addition, depending on the production method, the semiconductor wafer may be thinly ground with the bumps still attached. In this way, a protective wafer or sheet is attached to a semiconductor wafer with bumps on the surface or a semiconductor wafer with a large unevenness in the wiring pattern on the surface, and a protective processing tape or sheet is attached to the thin wafer. However, since the strength is not sufficient, there has been a problem that the semiconductor wafer is broken (cracked) or warped in the semiconductor wafer.

Accordingly, an object of the present invention is to provide a semiconductor wafer that can be thinly processed by suppressing or preventing the occurrence of breakage and warping of a semiconductor wafer having a wiring pattern or bump having a large unevenness on the surface. A processing method and an adhesive sheet for processing a semiconductor wafer used in the processing method of the semiconductor wafer are provided.
Another object of the present invention is to suppress or prevent the occurrence of breakage and warpage in a thin processing step of a semiconductor wafer on which a wiring pattern or bump having a large unevenness is formed on the surface, and further to the next step. An object of the present invention is to provide a semiconductor wafer processing method capable of easily carrying a transfer process and a semiconductor wafer processing adhesive sheet used in the semiconductor wafer processing method.
Still another object of the present invention is to easily remove a pressure-sensitive adhesive sheet used in thin processing of a semiconductor wafer after the thin processing and obtain a semiconductor wafer subjected to the thin processing. An object of the present invention is to provide a semiconductor wafer processing method and a semiconductor wafer processing pressure-sensitive adhesive sheet used in the semiconductor wafer processing method.

  As a result of diligent studies to solve the above problems, the present inventors have found that a semiconductor wafer is formed via an adhesive sheet when thin processing is performed on a semiconductor wafer having a wiring pattern or bump having a large unevenness on the surface. It has been found that when the wafer is fixed to the support, the semiconductor wafer can be thinned while suppressing or preventing the occurrence of breakage and warping. The present invention has been completed based on these findings.

  That is, the present invention is a method of processing a semiconductor wafer by performing a thin processing on a semiconductor wafer on which a wiring pattern and / or bumps having a maximum unevenness of 0.1 to 350 μm are formed on the surface, A semiconductor wafer processing method characterized in that a semiconductor wafer is fixed to a support via an adhesive sheet and subjected to thin processing.

  The pressure-sensitive adhesive sheet has a pressure-sensitive adhesive surface to be bonded to the semiconductor wafer, and reduces the adhesive force to the semiconductor wafer on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet bonded to the semiconductor wafer after thin processing of the semiconductor wafer. It is preferable to have a configuration capable of. Moreover, the adhesive layer used as the adhesive surface of the adhesive sheet bonded together to a semiconductor wafer may be formed through the intermediate | middle layer. As the pressure-sensitive adhesive layer serving as the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet bonded to such a semiconductor wafer, an energy ray curable pressure-sensitive adhesive layer or a heat-peeling pressure-sensitive adhesive layer is suitable.

  Further, the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive surface to be bonded to the support, and reduces the adhesive force to the support on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet bonded to the support after thin processing of the semiconductor wafer. It is preferable to have a configuration that can be achieved. As an adhesive layer used as the adhesive surface of the adhesive sheet bonded together to such a support body, an energy-beam curable adhesive layer or a heat-peelable adhesive layer is suitable.

  In the present invention, after the thinning process of the semiconductor wafer, the surface subjected to the thinning process is mounted with an adhesive tape or sheet for dicing, and the adhesive sheet used for fixing to the support is peeled off from the semiconductor wafer. be able to. Under the present circumstances, it is possible to peel the adhesive sheet used when fixing to a support body from a semiconductor wafer with a peel.

  The present invention also provides a pressure-sensitive adhesive sheet for processing a semiconductor wafer, wherein the pressure-sensitive adhesive sheet has at least one surface as a pressure-sensitive adhesive surface and is used in the method for processing a semiconductor wafer.

  According to the semiconductor wafer processing method of the present invention, the semiconductor wafer having a wiring pattern or bump having a large unevenness on the surface can be subjected to thin processing while suppressing or preventing the occurrence of breakage or warping. it can. In addition, it is possible to suppress or prevent the occurrence of breakage and warpage in a thin processing process of a semiconductor wafer on which wiring patterns and bumps having a large unevenness are formed on the surface, and to easily carry the transport process to the next process. be able to. Furthermore, the adhesive sheet used in the thin processing of the semiconductor wafer can be easily peeled off after the thin processing, and a semiconductor wafer subjected to the thin processing can be easily obtained.

  Embodiments of the present invention will be described below in detail with reference to the drawings as necessary. In addition, the same code | symbol may be attached | subjected to the same member, a part, etc.

  In the method for processing a semiconductor wafer according to the present invention, as shown in FIG. 1, the semiconductor wafer is subjected to thin processing with the semiconductor wafer fixed to a support via an adhesive sheet. FIG. 1 is a schematic process diagram showing an example of a semiconductor wafer processing method of the present invention. Specifically, in FIG. 1, (a) shows an example of a semiconductor wafer on which bumps are formed on the surface, and (b) shows the surface on which bumps of the semiconductor wafer shown in (a) are formed. 2 shows a state in which a double-sided pressure-sensitive adhesive sheet is bonded as a semiconductor wafer processing pressure-sensitive adhesive sheet, and (c) shows a state in which a support plate is bonded to the other surface of the double-sided pressure-sensitive adhesive sheet shown in (b). , (D) shows a state in which thin processing is performed on the back surface of the semiconductor wafer fixed to the support plate via the double-sided adhesive sheet, and (e) shows the state of the semiconductor wafer subjected to thin processing. The surface shows the state where the adhesive tape or sheet for dicing is bonded to the surface, (f) shows the state where the support plate is peeled off, (g) shows the state where the double-sided adhesive sheet is peeled off, and the adhesive tape for dicing or Semiconductor with sheet attached Shows a state in which obtained the wafer.

  In FIG. 1, 1 is a semiconductor wafer, 1a is a front surface (wiring pattern forming surface) of the semiconductor wafer 1, 1b is a back surface (wiring pattern non-forming surface) of the semiconductor wafer 1, 1c is a bump, 2 is a double-sided adhesive sheet, 2a is Base material, 2b is an adhesive layer, 2c is an adhesive layer, 2d is a release liner, 3 is a support plate, 4 is a grinding machine (grinder), 5 is an adhesive tape for dicing, 5a is a base material, and 5b is an adhesive layer It is. In the semiconductor wafer 1, wiring patterns (circuit patterns) and bumps 1c are formed on the front surface 1a, and wiring patterns and bumps are not formed on the back surface 1b. The double-sided pressure-sensitive adhesive sheet 2 has a configuration in which a pressure-sensitive adhesive layer 2b is formed on one surface of a base material 2a, and a pressure-sensitive adhesive layer 2c and a release liner 2d are formed in this order on the other surface. Furthermore, the adhesive tape 5 for dicing has the structure by which the adhesive layer 5b was formed in the single side | surface of the base material 5a.

[Semiconductor wafer]
As the semiconductor wafer, as shown in FIG. 1A, in addition to the semiconductor wafer 1 having a configuration in which a wiring pattern and a bump are formed on one surface thereof, only one of the wiring pattern and the bump is formed. A semiconductor wafer having the structure described above can be used. Such a wiring pattern or bump may have a large unevenness difference. For example, the maximum unevenness difference may be 0.1 to 350 μm (preferably 1 to 200 μm, more preferably 3 to 150 μm). Therefore, as a semiconductor wafer, for example, a semiconductor wafer having a wiring pattern and / or bumps having a maximum unevenness of 0.1 to 350 μm (preferably 1 to 200 μm, more preferably 3 to 150 μm) on the surface is formed. Can be used.

  Wiring patterns and bumps can be formed according to a conventional method. For example, the wiring pattern can be formed into a desired pattern using a known or conventional wiring pattern forming method. The bumps can be formed in a desired size and shape on the surface (for example, on a wiring pattern forming surface on which a desired pattern is formed) using a known or conventional bump forming method.

  The material of the semiconductor wafer is not particularly limited, and any known or commonly used material can be used. Specifically, examples of the semiconductor wafer include a silicon-based semiconductor wafer and a gallium-arsenic-based semiconductor wafer.

[Semiconductor wafer processing adhesive sheet]
In the semiconductor wafer processing method of the present invention, a double-sided pressure-sensitive adhesive sheet 2 can be attached to the surface 1a of the semiconductor wafer 1 as shown in FIG. . That is, the double-sided pressure-sensitive adhesive sheet 2 is used as a pressure-sensitive adhesive sheet (a semiconductor wafer processing pressure-sensitive adhesive sheet) for fixing a semiconductor wafer to a support. The form of such a pressure-sensitive adhesive sheet for processing a semiconductor wafer is not particularly limited. For example, a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive surface on both sides, or a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive surface on one side (single-sided pressure-sensitive adhesive sheet). Any form may be sufficient. When a double-sided PSA sheet is used as the semiconductor wafer processing PSA sheet, the double-sided PSA sheet may be a double-sided PSA sheet with a substrate as shown in FIG. A less-type double-sided pressure-sensitive adhesive sheet may be used.

(Base material)
As described above, the double-sided pressure-sensitive adhesive sheet 2 includes the base material 2a, the pressure-sensitive adhesive layer 2b, and the pressure-sensitive adhesive layer 2c. The base material 2a is a supporting matrix such as the pressure-sensitive adhesive layer 2b and the pressure-sensitive adhesive layer 2c, and a known or commonly used pressure-sensitive adhesive tape or sheet base material can be used. Specifically, as the base material 2a, for example, a plastic base material such as a plastic film or sheet; a metal base material such as a metal foil or metal plate such as an aluminum foil or nickel foil; a cloth, a nonwoven fabric, a net, Fiber base materials such as aramid fiber base materials; paper base materials such as paper; foams such as foam sheets, and laminates thereof (particularly, laminates of plastic base materials and other base materials, A suitable thin leaf body such as a laminate of plastic films (or sheets) can be used. As the substrate 2a, a plastic substrate such as a plastic film or sheet can be suitably used. Examples of the material for such a plastic substrate include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyimide; polyetherimide; polyphenyl sulfate; polyamide (nylon) ), Amide resins such as wholly aromatic polyamide (aramid); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); polyether ether ketone (PEEK); polyethylene (PE), polypropylene (PP), ethylene-propylene Examples thereof include olefin resins such as polymers, ethylene-vinyl acetate copolymers (EVA) and the like containing α-olefins as monomer components; fluorine resins; silicone resins. These materials can be used alone or in combination of two or more.

  The base material 2a may have a single layer form or may have a laminated form. In addition, as a base material 2a, when using a radiation curable substance for adhesives, such as the adhesive layer 2b and the adhesive layer 2c, it is preferable to use the thing which does not inhibit transmission of a radiation.

  The thickness of the substrate 2a is generally 500 μm or less (preferably 1 to 300 μm, more preferably 5 to 250 μm), but is not limited thereto.

  In addition, in order to improve adhesiveness with adhesive layers, such as the adhesive layer 2b and the adhesive layer 2c, on the surface of the base material 2a, it is common surface treatment, for example, chromic acid, on the surface at the side of the adhesive layer Oxidation by chemical or physical methods such as treatment, exposure to ozone, exposure to flame, exposure to high piezoelectric impact, ionizing radiation treatment, etc. may be applied, and coating treatment with undercoat or release agent etc. May be.

(Adhesive surface to be bonded to semiconductor wafer)
The pressure-sensitive adhesive layer 2b is used as a pressure-sensitive adhesive layer to be bonded to a semiconductor wafer. That is, in the double-sided pressure-sensitive adhesive sheet 2, the surface of the pressure-sensitive adhesive layer 2 b is an adhesive surface that is bonded to the semiconductor wafer 1. Examples of the pressure-sensitive adhesive for forming such a pressure-sensitive adhesive layer 2b include an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a vinyl alkyl ether-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, and a polyamide-based pressure-sensitive adhesive. , Urethane-based adhesives, fluorine-based adhesives, styrene-diene block copolymer-based adhesives, creep characteristics-improving pressure-sensitive adhesives in which a melting point of about 200 ° C. or less is blended with a hot-melt resin A well-known adhesive can be used 1 type or in combination of 2 or more types. In addition to polymer components such as an adhesive component (base polymer), the pressure-sensitive adhesive is a crosslinking agent (for example, a polyisocyanate-based crosslinking agent, an alkyletherified melamine-based crosslinking agent, etc.), depending on the type of the pressure-sensitive adhesive, Appropriate additives such as tackifiers (for example, rosin derivative resins, polyterpene resins, petroleum resins, oil-soluble phenol resins that are solid, semi-solid or liquid at room temperature), plasticizers, fillers, anti-aging agents, etc. May be included. The pressure-sensitive adhesive may be any form of pressure-sensitive adhesive such as an emulsion-based pressure-sensitive adhesive or a solvent-based pressure-sensitive adhesive.

  The pressure-sensitive adhesive layer 2b is preferably a pressure-sensitive adhesive layer (adhesive force-reducing pressure-sensitive adhesive layer) that can be easily peeled off by reducing the adhesive force at an appropriate time. That is, the pressure-sensitive adhesive sheet for processing a semiconductor wafer has a pressure-sensitive adhesive surface to be bonded to the semiconductor wafer, and the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet for processing a semiconductor wafer bonded to the semiconductor wafer after thin processing of the semiconductor wafer. It is preferable to have a configuration capable of reducing the adhesive force to the semiconductor wafer. As described above, when the pressure-sensitive adhesive layer 2b is an adhesive force-reducing pressure-sensitive adhesive layer, peeling from the semiconductor wafer 1 is easy, and the semiconductor wafer 1 is damaged (cracked) when the semiconductor wafer 1 is peeled off. It can be peeled off without causing it. Even if the pressure-sensitive adhesive layer 2b is a normal pressure-sensitive adhesive layer (pressure-sensitive adhesive layer whose adhesive force cannot be reduced), as shown below, for example, by using a pressure-sensitive adhesive tape or sheet for dicing. The semiconductor wafer 1 can be easily peeled without causing damage (cracking or the like).

  As a pressure-sensitive adhesive (adhesive strength-reduced pressure-sensitive adhesive) that forms such an adhesive strength-reduced pressure-sensitive adhesive layer, a heat-peelable pressure-sensitive adhesive (heat-peelable pressure-sensitive adhesive), an energy ray-curable pressure-sensitive adhesive, or the like is used. Can do. The heat-peelable pressure-sensitive adhesive is a pressure-sensitive adhesive that can be foamed and / or expanded by heating, and the adhesive force can be reduced by foaming and / or expansion by heating. As such a heat-peelable pressure-sensitive adhesive, for example, at least a pressure-sensitive adhesive (pressure-sensitive adhesive) for imparting tackiness, and a thermally expandable microsphere (microcapsule) for imparting thermal expansibility Can be used. The pressure-sensitive adhesive used in the heat-peelable pressure-sensitive adhesive is not particularly limited, and the pressure-sensitive adhesives exemplified above (for example, acrylic pressure-sensitive adhesive, rubber pressure-sensitive adhesive, silicone pressure-sensitive adhesive, vinyl alkyl ether pressure-sensitive adhesive, polyester) -Based adhesives, polyamide-based adhesives, urethane-based adhesives, fluorine-based adhesives, styrene-diene block copolymer-based adhesives, creep property improving adhesives, and the like. Moreover, as a thermally expansible microsphere, it can select from a well-known thermally expansible microsphere suitably. As the thermally expandable microsphere, a foaming agent that is encapsulated in a microcapsule can be suitably used. Examples of such thermally expandable microspheres include microspheres in which substances such as isobutane, propane, and pentane that are easily gasified and expanded by heating are encapsulated in an elastic shell. The shell is often formed of a hot-melt material or a material that is destroyed by thermal expansion. Examples of the substance forming the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Thermally expandable microspheres can be produced by a conventional method such as a coacervation method or an interfacial polymerization method. Examples of thermally expandable microspheres include commercially available products such as Matsumoto Microsphere [trade name, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.].

  The compounding amount of the heat-expandable microspheres can be appropriately set according to the expansion ratio, the lowering of the adhesive strength of the heat-releasable pressure-sensitive adhesive layer, etc., but generally the polymer component ( For example, it is 5 to 200 parts by weight (preferably 15 to 75 parts by weight) with respect to 100 parts by weight of the base polymer of the adhesive. The particle diameter (average particle diameter) of the heat-expandable microspheres can be appropriately selected according to the thickness of the heat-peelable pressure-sensitive adhesive layer, and is, for example, 5 to 120 μm (preferably 10 to 75 μm). You can choose from a range. Moreover, the thermally expansible microsphere which has moderate intensity | strength which does not burst until a volume expansion coefficient becomes 1.5-10 times (preferably 2-5 times) is preferable.

  The energy ray-curable pressure-sensitive adhesive is a pressure-sensitive adhesive that has adhesiveness and can be cured by energy rays (or radiation), and the adhesive force can be reduced by curing with energy rays. As such an energy ray-curable pressure-sensitive adhesive, for example, a pressure-sensitive adhesive in which a functional group-containing compound containing a plurality of crosslinkable functional groups such as a polyfunctional monomer is blended in a base material (pressure-sensitive adhesive) is necessary. A radiation curable pressure sensitive adhesive containing a radiation polymerization initiator and a pressure sensitive adhesive having a polymer component copolymerized as a monomer component with a functional group-containing compound containing a plurality of crosslinkable functional groups such as polyfunctional monomers. A radiation curable pressure-sensitive adhesive containing a radiation polymerization initiator as required is included.

  As a radiation curable pressure-sensitive adhesive, a radiation polymerization initiator is blended with a pressure-sensitive adhesive in which a functional group-containing compound containing a plurality of crosslinkable functional groups such as a polyfunctional monomer is blended in a base material (pressure-sensitive adhesive). The radiation-curable pressure-sensitive adhesive that is used can be suitably used. As said base material, well-known adhesives, such as an acrylic adhesive, a rubber adhesive, a silicone adhesive, and a urethane adhesive, can be used, for example. A preferred base material includes an acrylic pressure-sensitive adhesive. The base material may be composed of one kind of component or may be composed of two or more kinds of components. Further, as the functional group-containing compound containing a plurality of crosslinkable functional groups, a radiation curable low molecular weight compound or a radiation curable resin can be used. Specifically, the radiation-curable low molecular weight compound is not particularly limited as long as it can be cured by energy rays (radiation) such as visible light, ultraviolet rays, and electron beams. For example, trimethylolpropane triacrylate, Tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol Examples include diacrylate. Examples of the radiation curable resin include ester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, and acrylic resin (meth) having a (meth) acryloyl group at the molecular end. Photosensitive reactive group-containing polymers such as acrylates, thiol-ene addition type resins having an allyl group at the molecular terminal, photocationic polymerization type resins, cinnamoyl group-containing polymers such as polyvinyl cinnamate, diazotized amino novolak resins and acrylamide type polymers Or an oligomer etc. are mentioned. In addition, when using radiation curable resin, the said base material is not necessarily required.

  The compounding amount of the functional group-containing compound containing a plurality of crosslinkable functional groups is, for example, 5 to 500 parts by weight (preferably 15 to 300 parts by weight, more preferably 20 to 150 parts by weight) with respect to 100 parts by weight of the base material. ).

  In addition, as a radiation curing type adhesive, an ultraviolet (UV) reactive adhesive polymer can also be used. Examples of the UV-reactive adhesive polymer include a photosensitive acrylic adhesive in which a photosensitive functional group-containing compound such as a vinyl group is introduced into an acrylic polymer molecule by a chemical reaction starting from an active functional group such as a hydroxyl group or a carboxyl group. Etc.

  Examples of the radiation polymerization initiator include acetophenone initiator, benzoin ether initiator, ketal compound, aromatic sulfonyl chloride compound, photoactive oxime compound, benzophenone compound, thioxanthone compound, camphorquinone, Examples thereof include halogenated ketones, acyl phosphinoxides, acyl phosphonates, and the like. The blending amount of the radiation polymerization initiator can be appropriately selected from the ratio of the radiation polymerization initiator in the known radiation curable pressure-sensitive adhesive.

  In addition to the above components, the radiation-curable pressure-sensitive adhesive has appropriate additives such as a thermal polymerization initiator, a crosslinking agent, a tackifier, and a vulcanizing agent in order to obtain appropriate viscoelasticity before and after radiation curing. You may mix | blend as needed. Moreover, a radiation polymerization accelerator can be used in combination with the radiation polymerization initiator.

  The pressure-sensitive adhesive layer 2b can be formed using a known method for forming a pressure-sensitive adhesive layer (such as a coating method or a transfer method). Specifically, the pressure-sensitive adhesive layer 2b is formed, for example, by a method of applying a pressure-sensitive adhesive on a predetermined surface of the substrate 2a, or by applying a pressure-sensitive adhesive on an appropriate release liner (separator). The pressure-sensitive adhesive layer can be formed by a method of transferring the adhesive layer onto a predetermined surface of the substrate 2a.

  The thickness of the pressure-sensitive adhesive layer 2b is not particularly limited as long as it can be peeled off from the semiconductor wafer, but is preferably 1 to 200 μm, more preferably 2 to 100 μm from the viewpoint of coexistence of adhesiveness and peelability. is there. When the thickness of the pressure-sensitive adhesive layer 2b is less than 1 μm, for example, as shown below, when an intermediate layer is provided between the pressure-sensitive adhesive layer 2b and the substrate 2a, the pressure-sensitive adhesive layer 2b is destroyed. On the other hand, when the thickness exceeds 200 μm, it becomes difficult to follow the uneven shape of the surface 1 a of the semiconductor wafer 1 when the double-sided pressure-sensitive adhesive sheet 2 is attached to the semiconductor wafer 1.

(Adhesive surface to be bonded to the support plate)
The pressure-sensitive adhesive layer 2c is used as a pressure-sensitive adhesive layer to be bonded to a support (such as a support plate). That is, in the double-sided pressure-sensitive adhesive sheet 2, the surface of the pressure-sensitive adhesive layer 2 c is an adhesive surface that is bonded to the support plate 3. As an adhesive for forming such an adhesive layer 2c, the same adhesive as the adhesive for forming the adhesive layer 2b (for example, an acrylic adhesive, a rubber adhesive, a silicone adhesive) , Vinyl alkyl ether-based adhesives, polyester-based adhesives, polyamide-based adhesives, urethane-based adhesives, fluorine-based adhesives, styrene-diene block copolymer-based adhesives, creep property-adhesive adhesives, etc.) be able to. In addition to polymer components such as an adhesive component (base polymer), the pressure-sensitive adhesive is a crosslinking agent (for example, a polyisocyanate-based crosslinking agent, an alkyletherified melamine-based crosslinking agent, etc.), depending on the type of the pressure-sensitive adhesive, Appropriate additives such as tackifiers (for example, rosin derivative resins, polyterpene resins, petroleum resins, oil-soluble phenol resins that are solid, semi-solid or liquid at room temperature), plasticizers, fillers, anti-aging agents, etc. May be included. The pressure-sensitive adhesive may be any form of pressure-sensitive adhesive such as an emulsion-based pressure-sensitive adhesive or a solvent-based pressure-sensitive adhesive.

  The pressure-sensitive adhesive layer 2c is a pressure-sensitive adhesive layer (adhesive strength-reducing pressure-sensitive adhesive layer) that can be easily peeled off by reducing the adhesive force at an appropriate time, like the pressure-sensitive adhesive layer 2b. Preferably there is. That is, the pressure-sensitive adhesive sheet for processing a semiconductor wafer has a pressure-sensitive adhesive surface that is bonded to the support, and the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet for processing a semiconductor wafer that is bonded to the support after the thin processing of the semiconductor wafer. It is preferable to have a configuration capable of reducing the adhesive force to the support. Thus, when the pressure-sensitive adhesive layer 2c is an adhesive force-reducing pressure-sensitive adhesive layer, peeling from the support plate 3 is easy, and when the support plate 3 is peeled off, the support plate 3 is not damaged. The support plate 3 can be reused. As the pressure-sensitive adhesive (adhesive strength-reduced pressure-sensitive adhesive) that forms such an adhesive strength-reduced pressure-sensitive adhesive layer, as described above, a heat-peelable pressure-sensitive adhesive (heat-peelable pressure-sensitive adhesive) or an energy ray-curable pressure-sensitive adhesive An agent or the like can be used.

  The pressure-sensitive adhesive layer 2c can be formed using a known method for forming a pressure-sensitive adhesive layer (coating method, transfer method, etc.) in the same manner as the pressure-sensitive adhesive layer 2b. Specifically, the pressure-sensitive adhesive layer 2c is formed, for example, by a method of applying a pressure-sensitive adhesive on a predetermined surface of the substrate 2a or by applying a pressure-sensitive adhesive on an appropriate release liner (separator). The pressure-sensitive adhesive layer can be formed by a method of transferring the adhesive layer onto a predetermined surface of the substrate 2a.

  The thickness of the pressure-sensitive adhesive layer 2c is not particularly limited as long as it can be peeled off from a support (such as a support plate) as in the case of the pressure-sensitive adhesive layer 2b, but from the viewpoint of coexistence of adhesiveness and peelability, 10-300 micrometers is preferable, More preferably, it is 20-200 micrometers.

(Middle layer)
In the present invention, it is preferable that the pressure-sensitive adhesive layer 2b to be bonded to the semiconductor wafer 1 and the pressure-sensitive adhesive layer 2c to be bonded to the support plate 3 are formed via an intermediate layer. In particular, the pressure-sensitive adhesive layer 2b is preferably formed through an intermediate layer from the viewpoint of the ability to follow a wiring pattern or bump having a large unevenness difference, the peelability of a double-sided pressure-sensitive adhesive sheet from a semiconductor wafer, and the like. It is. For example, when the double-sided pressure-sensitive adhesive sheet 2 is bonded to the semiconductor wafer 1 by providing the intermediate layer between the base material 2a and the pressure-sensitive adhesive layer 2b, the surface of the double-sided pressure-sensitive adhesive sheet 2 (surface of the pressure-sensitive adhesive layer 2b). Can be satisfactorily followed by the shape of the surface of the semiconductor wafer 1 (surface shape on which wiring patterns and bumps having a large unevenness are formed), and the bonding area can be increased. Further, when the pressure-sensitive adhesive layer 2b is a heat-peelable pressure-sensitive adhesive layer, when the double-sided pressure-sensitive adhesive sheet 2 is peeled off from the semiconductor wafer 1 by heating, the heat expansion of the pressure-sensitive adhesive layer 2b is highly controlled (accurately). The heat-peelable pressure-sensitive adhesive layer 2b can be preferentially expanded uniformly in the thickness direction. In addition, an intermediate | middle layer is a layer provided as needed, and does not necessarily need to be provided.

  Such an intermediate layer preferably has an elastic modulus of 30 to 1000 kPa (preferably 50 to 700 kPa). Moreover, as an intermediate | middle layer, it is desirable that a gel fraction is 20% or less (preferably 10% or less).

  Thus, when the elastic modulus of the intermediate layer is 30 to 1000 kPa, for example, when the intermediate layer is formed between the pressure-sensitive adhesive layer 2b and the substrate 2a, the surface of the pressure-sensitive adhesive layer 2b is the semiconductor wafer 1. Since the double-sided pressure-sensitive adhesive sheet 2 can be bonded to the semiconductor wafer 1 without bubbles (without creating a gap at the interface) following the uneven shape of the surface 1a of the semiconductor wafer 1 (when the semiconductor wafer 1 is ground) It is possible to prevent water from entering and cracking from the gaps effectively during thin processing. If the elastic modulus of the intermediate layer is less than 30 kPa, the intermediate layer becomes soft, so the sheet or tape shape stability is lowered. For example, when a long-term storage or load is applied, the double-sided adhesive sheet can be deformed. Increases nature. Further, the pressure applied to the double-sided pressure-sensitive adhesive sheet may cause a problem that the intermediate layer protrudes and contaminates the semiconductor wafer. On the other hand, when the elastic modulus of the intermediate layer exceeds 1000 kPa, the intermediate layer becomes hard, for example, the followability to the uneven shape of the surface of the semiconductor wafer is reduced, and the semiconductor wafer and the double-sided pressure-sensitive adhesive sheet are separated during grinding of the semiconductor wafer. Water intrusion, cracks, and dimples are likely to occur from the gaps at the interface.

  Further, when the gel fraction of the intermediate layer exceeds 20%, for example, the followability to the uneven shape on the surface of the semiconductor wafer is lowered, and cracks and dimples are likely to occur during grinding of the semiconductor wafer. In this case, even if the elastic modulus of the intermediate layer is within the above range, if the gel fraction exceeds 20%, the followability decreases, so the elastic modulus and the gel fraction are within the above range. It is preferable.

  In addition, the elastic modulus (G ′) of the intermediate layer is a condition of 25 ° C., plate: φ7.5 parallel plate, frequency: 1 Hz using a dynamic viscoelasticity measuring device (“Rheometrics ARES” manufactured by Rheometrics). The elastic modulus measured at. Further, the gel fraction (%) of the intermediate layer means a ratio of the intermediate layer that does not dissolve when immersed in ethyl acetate at 25 ° C. for 7 days.

  The thickness of the intermediate layer can be appropriately selected depending on, for example, the unevenness of the surface of the semiconductor wafer and within a range that does not impair the retainability and protective properties of the semiconductor wafer, and preferably 20 to 500 μm ( More preferably, it is 30-200 micrometers. When the thickness of the intermediate layer is less than 20 μm, the followability of the double-sided pressure-sensitive adhesive sheet to the uneven shape on the surface of the semiconductor wafer is lowered, and cracks and dimples are likely to occur during grinding of the semiconductor wafer. On the other hand, if the thickness of the intermediate layer exceeds 500 μm, it takes time for the intermediate layer to stick out and the application of the double-sided pressure-sensitive adhesive sheet takes a long time, and the work efficiency decreases, and it cannot be set in the grinding machine. ) Problems arise. Moreover, when peeling a double-sided adhesive sheet from a semiconductor wafer, there exists a possibility that the thin semiconductor wafer after grinding may be damaged by the bending stress of a double-sided adhesive sheet.

As the ratio of cases, the thickness of the intermediate layer (t _1), the thickness of the adhesive layer 2b (t ₂₎ to the intermediate layer, provided between the pressure-sensitive adhesive layer 2b and the base material 2a, t ₂ / t ₁ = 0.01 to 0.5 (preferably 0.02 to 0.3). When t ₂ / t ₁ is less than 0.01, for example, when the pressure-sensitive adhesive layer 2b is an energy ray-curable pressure-sensitive adhesive layer, the adhesive strength is not sufficiently lowered after irradiation with radiation, and peeling may be difficult. There is. On the other hand, if t ₂ / t ₁ exceeds 0.5, the effect of the intermediate layer is not exhibited, and for example, it becomes difficult to follow the uneven shape of the surface of the semiconductor wafer, and cracks occur during grinding of the semiconductor wafer. And dimples are likely to occur.

  As a material of such an intermediate layer, from the viewpoint of good adhesion (sticking property) with pressure-sensitive adhesive layers such as pressure-sensitive adhesive layer 2b and pressure-sensitive adhesive layer 2c, and easy adjustment of elastic modulus. In addition to resins such as acrylic polymers and double bond-introduced acrylic polymers that can be cured by irradiation with energy rays (for example, esters (meth) acrylates having (meth) acryloyl groups at the molecular ends), various adhesives Although an agent etc. can be used conveniently, if it has the said characteristic, it can use without a restriction | limiting in particular.

  The intermediate layer may be a single layer or may be composed of two or more layers.

  In the present invention, the double-sided pressure-sensitive adhesive sheet is used by being attached to a semiconductor wafer provided with a wiring pattern or a bump having a large unevenness on the surface. It is preferably processed by stamping or the like so as to have a shape corresponding to the shape of the surface of the wafer.

  In addition, when using a double-sided pressure-sensitive adhesive sheet with a substrate as shown in FIG. 1B as a semiconductor wafer processing pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layers on both sides may be formed of the same pressure-sensitive adhesive, You may be formed with the different adhesive. Therefore, for example, when both the pressure-sensitive adhesive layers are heat-peelable pressure-sensitive adhesive layers, the heat-peeling start temperature when peeling the semiconductor wafer or the support may be the same or different. However, when separating the semiconductor wafer and the support separately, it is important that the heat-peeling pressure-sensitive adhesive layer on the side to be peeled first (for example, the support side) has a lower heat-peeling start temperature. is there.

  In the present invention, a double-sided pressure-sensitive adhesive sheet with a substrate is preferable as the pressure-sensitive adhesive sheet for processing semiconductor wafers. Among them, the pressure-sensitive adhesive layers on both sides are different peeling means (for example, peeling means by heating, peeling by energy beam irradiation). For example, a double-sided pressure-sensitive adhesive sheet with a base material that can be peeled off by a peeling means using a peeling means) can be suitably used. As such a double-sided pressure-sensitive adhesive sheet with a substrate, for example, one surface is an adhesive surface by an energy ray curable adhesive layer, and the other surface is an adhesive surface by a heat-peelable adhesive layer. Double-sided pressure-sensitive adhesive sheet with a base material, and one surface is a pressure-sensitive adhesive surface by a normal pressure-sensitive adhesive layer (a pressure-sensitive adhesive layer that can be peeled off by a peeling means by peeling, not by a means of peeling by heating or energy ray irradiation) And the other surface is a double-sided pressure-sensitive adhesive sheet with a base material that has a heat-peeling pressure-sensitive adhesive layer or an energy-ray-curing pressure-sensitive adhesive layer. A double-sided pressure-sensitive adhesive sheet with a base material having a pressure-sensitive adhesive surface due to a mold-type pressure-sensitive adhesive layer and the other surface being a pressure-sensitive adhesive surface due to a heat-peelable pressure-sensitive adhesive layer is suitable. Thus, when the pressure-sensitive adhesive sheet for processing a semiconductor wafer is a double-sided pressure-sensitive adhesive sheet with a substrate that can be peeled off by peeling means having different pressure-sensitive adhesive layers on both sides, the semiconductor wafer and the support can be separated easily. It can be peeled off.

  Also, when the adhesive sheet for semiconductor wafer processing is a double-sided adhesive sheet with a base material that can be peeled off by different peeling means, the semiconductor wafer may be weak against heat, The pressure-sensitive adhesive surface to be bonded to the semiconductor wafer in the double-sided pressure-sensitive adhesive sheet with a base material may be a pressure-sensitive adhesive surface by a heat-peelable pressure-sensitive adhesive layer, but it is a pressure-sensitive adhesive surface by an energy ray curable pressure-sensitive adhesive layer or a normal pressure-sensitive adhesive layer. It is desirable that

  In addition, when using a single-sided adhesive sheet as an adhesive sheet for semiconductor wafer processing, for example, two single-sided adhesive sheets are used, the adhesive surface of one single-sided adhesive sheet is bonded to a semiconductor wafer, and the adhesive of the other single-sided adhesive sheet is used. The semiconductor wafer can be fixed to the support via the adhesive sheet by bonding the surfaces to the support and bonding the back surfaces of the two single-sided adhesive sheets by various bonding means. Note that the means for laminating the back surfaces of the two single-sided adhesive sheets is not particularly limited, and known laminating means (for example, means for laminating using a wax, an adhesive, an adhesive, an adhesive tape, or a sheet) Etc.) can be employed.

  As the base material and the pressure-sensitive adhesive layer in such a single-sided pressure-sensitive adhesive sheet, a pressure-sensitive adhesive sheet having a base material, a pressure-sensitive adhesive layer and the like corresponding to the double-sided pressure-sensitive adhesive sheet can be used.

[Support]
After sticking the double-sided pressure-sensitive adhesive sheet 2 on the surface 1a of the semiconductor wafer 1, the release liner 2d protecting the pressure-sensitive adhesive layer 2c of the double-sided pressure-sensitive adhesive sheet 2 is peeled off as shown in FIG. By attaching the support plate 3 on 2c, a semiconductor wafer reinforced by the support plate 3 as a support can be manufactured. As described above, a semiconductor wafer reinforced by a support via a semiconductor wafer processing adhesive sheet (sometimes referred to as a “reinforcing wafer”) includes a semiconductor wafer and a support via a semiconductor wafer processing adhesive sheet. If it has the structure by which these were bonded together, the order of the bonding will not be restrict | limited in particular. As a reinforcing wafer, for example, as shown in FIGS. 1A to 1C, after a double-sided pressure-sensitive adhesive sheet is pasted on the surface of a semiconductor wafer, a support is stuck on the other pressure-sensitive adhesive surface of the double-sided pressure-sensitive adhesive sheet. In addition to the configuration bonded in step 2, after pasting the double-sided pressure-sensitive adhesive sheet on the support, the structure laminated on the other pressure-sensitive adhesive surface of the double-sided pressure-sensitive adhesive sheet and the respective surfaces of the double-sided pressure-sensitive adhesive sheet, For example, a configuration in which the semiconductor wafer and the support are bonded in the order of being bonded in parallel is exemplified.

  As such a support, a support plate 3 having a plate shape can be suitably used as shown in FIG.

  The support is not particularly limited as long as it can reinforce a thinly processed semiconductor wafer. For example, a support made of the same material as the semiconductor wafer or a hard material is preferable to the semiconductor wafer. Specifically, when the support is a support plate, examples of the support plate include semiconductor wafers such as silicon wafers and glass wafers, metal plates such as SUS stainless steel plates and copper plates, and plastic plates such as acrylic resin plates. Is mentioned.

  The shape and size of the support such as the support plate are not particularly limited as long as the back surface of the semiconductor wafer can be processed thinly. However, as shown in FIG. The thing of the same size can be used suitably. When the support is a support plate, the thickness of the support plate is usually preferably about 400 to 800 μm, but is not limited thereto, and may be less than 400 μm or over 800 μm.

  The alignment between the double-sided pressure-sensitive adhesive sheet 2 and the semiconductor wafer 1 in FIG. 1B and the alignment between the double-sided pressure-sensitive adhesive sheet 2 and the support plate 3 in FIG. 1C are performed using an image recognition device. This can be done by recognizing the exact position and correcting the difference from the current positional relationship.

[Thin processing]
The back surface 1b of the semiconductor wafer 1 in the reinforcing wafer can be subjected to thin processing as shown in FIG. Specifically, in FIG. 1D, the position of the semiconductor wafer 1 is turned upside down, the support plate 3 of the reinforcing wafer is chucked, and the back surface 1b of the semiconductor wafer 1 is thinned. There is no particular limitation on the method of thinning the back surface of the semiconductor wafer in the reinforcing wafer. For example, as a thin processing method, a general method (back grinding method, etching method, etc.) can be employed. Examples of the thin processing machine include a grinding machine (back grinder), a CMP pad, and the like.

  The thin processing can be performed until the semiconductor wafer has a desired thickness.

  The reinforced wafer that has undergone the thin processing can be transferred to the next process. Specifically, for example, the position of the semiconductor wafer can be turned upside down and transferred to a subsequent process (for example, a dicing process).

[Removal of thinned semiconductor wafer]
After thin processing is performed on the back surface 1b of the semiconductor wafer 1, a dicing adhesive tape 5 is bonded to the back surface 1b of the semiconductor wafer 1 in the reinforcing wafer, as shown in FIG. A reinforcing wafer (wafer mount frame) to which 5 is attached can be produced. As described above, after the thin processing of the semiconductor wafer is performed, the surface subjected to the thin processing (back surface) is mounted with the dicing adhesive tape or sheet, and then the support or the semiconductor wafer processing adhesive sheet is peeled off. Can do. Such a dicing adhesive tape 5 is not particularly limited, and a known dicing adhesive tape can be used. Specifically, as the adhesive tape for dicing, an adhesive tape or sheet having a configuration in which an adhesive layer is formed on one surface of the substrate can be used. As the pressure-sensitive adhesive forming the base material or the pressure-sensitive adhesive layer, a known base material or pressure-sensitive adhesive can be used.

(Removal of support)
Then, after manufacturing a reinforced wafer (wafer mount frame) to which the dicing adhesive tape 5 is attached, as shown in FIG. 1 (f), the support plate 3 is peeled off from the wafer mount frame to form the surface 1a. It is possible to obtain the semiconductor wafer 1 in which the double-sided pressure-sensitive adhesive sheet 2 is attached and the dicing adhesive tape 5 is attached to the back surface 1b on which the thin processing is performed. When peeling the support plate 3 from the wafer mount frame, an appropriate peeling means (heating) according to the type of the pressure-sensitive adhesive layer 2c serving as the pressure-sensitive adhesive surface of the double-sided pressure-sensitive adhesive sheet 2 bonded to the support plate 3 is used. The support plate 3 can be peeled from the wafer mount frame (or the pressure-sensitive adhesive layer 2c) by utilizing a peeling means by (1), a peeling means by energy beam irradiation, a peeling means by peel, and the like. For example, when the pressure-sensitive adhesive layer 2c is a heat-peelable pressure-sensitive adhesive layer, the adhesive force between the support plate 3 and the pressure-sensitive adhesive layer 2c is reduced by heating the chuck table of the wafer mount frame to an arbitrary temperature. The plate 3 can be easily peeled from the wafer mount frame (or the adhesive layer 2c).

(Removal of adhesive sheet for semiconductor wafer processing)
After peeling the support plate 3 from the wafer mount frame, as shown in FIG. 1G, the double-sided pressure-sensitive adhesive sheet 2 affixed to the surface 1a of the semiconductor wafer 1 is peeled, and thin processing is performed. A semiconductor wafer 1 having a dicing adhesive tape 5 bonded to the back surface 1b can be obtained. When the double-sided pressure-sensitive adhesive sheet 2 is peeled from the semiconductor wafer 1, an appropriate one is selected according to the type of the pressure-sensitive adhesive layer 2 b serving as the pressure-sensitive adhesive surface of the double-sided pressure-sensitive adhesive sheet 2 bonded to the surface 1 a of the semiconductor wafer 1. The double-sided pressure-sensitive adhesive sheet 2 can be peeled from the semiconductor wafer 1 by using a peeling means (a peeling means by heating, a peeling means by irradiation with energy rays, a peeling means by peel, etc.). For example, when the pressure-sensitive adhesive layer 2b is an energy ray-curable pressure-sensitive adhesive layer, the double-sided pressure-sensitive adhesive sheet 2 can be peeled from the semiconductor wafer 1 by energy ray irradiation. In addition, when the pressure-sensitive adhesive layer 2b is a normal pressure-sensitive adhesive layer (adhesive layer that can be peeled off by peeling means by peeling, not by peeling means by heating or energy ray irradiation), the double-sided pressure-sensitive adhesive sheet 2 is made of semiconductor by peeling. The wafer 1 can be peeled off.

  In the present invention, after isolating the semiconductor wafer subjected to the thin processing, after mounting the semiconductor wafer thin processing, the surface subjected to the thin processing (back surface) is mounted with a dicing adhesive tape or sheet, Even if the peeling means of the adhesive sheet for semiconductor wafer processing from the semiconductor wafer is a peeling means by peel by peeling the support or the adhesive sheet for semiconductor wafer processing (peeling by the mount peeling method), the semiconductor wafer It is possible to peel more easily without breaking.

  In the semiconductor wafer processing method of the present invention, as described above, the semiconductor wafer is fixed to the support via the adhesive sheet and subjected to thin processing, so that the semiconductor wafer has the largest unevenness difference on the surface. Even a semiconductor wafer on which a wiring pattern and / or a bump having a thickness of 0.1 to 350 μm is formed can provide sufficient strength and rigidity for thin processing. Accordingly, the semiconductor wafer can be easily handled in the thin processing step, and processing by the wafer carrier is also possible. Further, damage to the semiconductor wafer can be minimized.

  Further, since a support (support wafer, etc.) is attached to the surface of the semiconductor wafer via a semiconductor wafer processing adhesive sheet (double-sided adhesive sheet, etc.), the conventional semiconductor wafer used for thin processing is used. No surface protection tape is required. Moreover, since the ready-made product provided as a semiconductor wafer can be used as the said support body, it is not necessary to produce separately.

  Furthermore, the semiconductor wafer processing pressure-sensitive adhesive sheet attached to the semiconductor wafer can be removed (peeled) from the semiconductor wafer by a peeling method such as a mount peeling method, so that the semiconductor wafer subjected to thin processing is broken. And can be easily taken out.

  In addition, a support (such as a support wafer) removed by a peeling method such as a thermal peeling method using a thermal peeling means can be reused.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited only to an Example.
(Production Example 1 of adhesive sheet)
Toluene solution prepared by blending 100 parts by weight of 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate (parts by weight ratio = 30/70/5) copolymer pressure sensitive adhesive with 1 part by weight of a polyurethane crosslinking agent On the polyester film (thickness 100 μm) as a base material, it was applied so that the thickness after drying was 10 μm and dried to form a rubbery organic elastic layer.

  Next, 100 parts by weight of 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate copolymer and 2 parts by weight of a polyurethane-based crosslinking agent were added to a heat-expandable microsphere (trade name “ A toluene solution containing 30 parts by weight of “Matsumoto Microsphere F-30D” (Matsumoto Yushi Seiyaku Co., Ltd .; average particle size 13.5 μm) was prepared, and this was dried on a separator so that the thickness after drying was 40 μm. After applying and drying to form a pressure-sensitive adhesive layer (thermally peelable pressure-sensitive adhesive layer), the rubber-like organic elastic body layer and the pressure-sensitive adhesive layer are in contact with the polyester film formed with the rubber-like organic elastic body. To obtain a heat-peelable pressure-sensitive adhesive sheet (sometimes referred to as “heat-peelable pressure-sensitive adhesive sheet A”).

  To the surface of the heat-peelable pressure-sensitive adhesive sheet A on the base material side, 100 parts by weight of 2-ethylhexyl acrylate-acrylic acid amide-acrylic acid (part by weight ratio = 75/20/5) copolymer pressure sensitive adhesive, A toluene solution containing 0.05 part by weight of an epoxy crosslinking agent is applied and dried so that the thickness after drying is 100 μm, and an intermediate layer (sometimes referred to as “intermediate layer A”) is obtained. Formed. The intermediate layer A had an elastic modulus of 500 kPa and a gel fraction of 1%.

  Subsequently, 2-ethylhexyl acrylate-acrylic acid-acrylamide (weight part ratio = 82/3/15) copolymer pressure sensitive adhesive 100 parts by weight (number average molecular weight 700,000), ester plasticizer 20 weights Part, 0.1 parts by weight of melamine cross-linking agent and 3 parts by weight of isocyanate cross-linking agent were applied on the separator so that the thickness after drying was 5 μm to form an adhesive layer, The adhesive layer and the intermediate layer A were bonded to the heat-peelable adhesive sheet A on which the intermediate layer A was formed to obtain a double-sided adhesive sheet (sometimes referred to as “double-sided adhesive sheet A”). .

  Accordingly, the double-sided pressure-sensitive adhesive sheet A has a rubber-like organic elastic layer and a pressure-sensitive adhesive layer (thermally peelable pressure-sensitive adhesive layer) formed in this order on one surface of the base material, and the intermediate layer A, The pressure-sensitive adhesive layer has a configuration formed in this order.

(Production Example 2 of adhesive sheet)
A heat-peelable pressure-sensitive adhesive sheet A was produced in the same manner as in Production Example 1 of the pressure-sensitive adhesive sheet. An intermediate layer A was formed on the surface of the heat-peelable pressure-sensitive adhesive sheet A on the base material side in the same manner as in Production Example 1 of the pressure-sensitive adhesive sheet. The intermediate layer A had an elastic modulus of 500 kPa and a gel fraction of 1%.

  Next, 43 parts by weight of 2-methacryloyl is added to 100 parts by weight of ethyl acrylate-butyl acrylate-2-hydroxyethyl acrylate (part by weight ratio = 78/100/40) copolymer (number average molecular weight 300,000). Oxyethyl isocyanate was subjected to an addition reaction to introduce a carbon-carbon double bond portion into a side chain in the polymer molecule. A blend of 1 part by weight of a polyisocyanate-based crosslinking agent and 3 parts by weight of an acetophenone-based photopolymerization initiator with respect to 100 parts by weight of a polymer into which the carbon-carbon double bond part has been introduced is dried on a separator. After coating to a thickness of 40 μm to form a pressure-sensitive adhesive layer (energy ray curable pressure-sensitive adhesive layer), the pressure-sensitive adhesive layer and the intermediate layer are applied to the heat-peelable pressure-sensitive adhesive sheet A on which the intermediate layer A is formed. A double-sided pressure-sensitive adhesive sheet (which may be referred to as “double-sided pressure-sensitive adhesive sheet B”) was obtained by bonding in a form in contact with A.

  Accordingly, the double-sided pressure-sensitive adhesive sheet B has a rubber-like organic elastic layer and a pressure-sensitive adhesive layer (thermally peelable pressure-sensitive adhesive layer) formed in this order on one surface of the base material, and the intermediate layer A, The pressure-sensitive adhesive layer (energy ray curable pressure-sensitive adhesive layer) has a structure formed in this order.

(Production Example 3 of pressure-sensitive adhesive sheet)
Toluene formed by blending 100 parts by weight of an acrylic acid 2-ethylhexyl-acrylic acid amide-acrylic acid (part by weight ratio = 75/20/5) copolymer pressure sensitive adhesive with 0.05 parts by weight of an epoxy crosslinking agent. The solution was applied onto a polyester film (thickness: 100 μm) as a substrate so that the thickness after drying was 100 μm and dried to form an intermediate layer A. The intermediate layer A had an elastic modulus of 500 kPa and a gel fraction of 1%.

  Subsequently, 2-ethylhexyl acrylate-acrylic acid-acrylamide (weight ratio = 82/3/15) copolymer pressure sensitive adhesive 100 parts by weight (number average molecular weight 700,000), ester plasticizer 20 parts by weight After adding 0.1 parts by weight of a melamine-based crosslinking agent and 3 parts by weight of an isocyanate crosslinking agent to form a pressure-sensitive adhesive layer on the separator so that the thickness after drying is 5 μm, A pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer and the intermediate layer A are in contact with the polyester film on which the layer A is formed, and having only one surface is a pressure-sensitive adhesive surface (sometimes referred to as “pressure-sensitive adhesive sheet C”) Obtained.

  Therefore, the said adhesive sheet C has the structure by which the intermediate | middle layer A and the adhesive layer were formed in this order on the one surface of the base material.

(Production Example 4 of adhesive sheet)
A polyester film having the intermediate layer A formed thereon was produced in the same manner as in Production Example 3 of the pressure-sensitive adhesive sheet. The intermediate layer A had an elastic modulus of 500 kPa and a gel fraction of 1%.

  Subsequently, 43 parts by weight of 2-methacryloyl is added to 100 parts by weight of an ethyl acrylate-butyl acrylate-hydroxy-2-acrylate (parts by weight = 78/100/40) copolymer (number average molecular weight 300,000). Oxyethyl isocyanate was subjected to an addition reaction to introduce a carbon-carbon double bond portion into a side chain in the polymer molecule. A blend of 1 part by weight of a polyisocyanate-based crosslinking agent and 3 parts by weight of an acetophenone-based photopolymerization initiator with respect to 100 parts by weight of a polymer into which the carbon-carbon double bond part has been introduced is dried on a separator. After the adhesive layer (energy ray curable adhesive layer) is formed by coating to a thickness of 40 μm, the adhesive layer and the intermediate layer A are in contact with the polyester film on which the intermediate layer A is formed. In such a manner, an adhesive sheet (sometimes referred to as “adhesive sheet D”) having an adhesive surface only on one side was obtained.

  Therefore, the said adhesive sheet D has the structure by which the intermediate | middle layer A and the adhesive layer (energy-beam curable adhesive layer) were formed in this order on the one surface of the base material.

(Production Example 5 of adhesive sheet)
43 parts by weight of 2-methacryloyloxyethyl isocyanate to 100 parts by weight of copolymer of ethyl acrylate-butyl acrylate-hydroxy-2-acrylate (parts by weight = 78/100/40) copolymer (number average molecular weight 300,000) The carbon-carbon double bond part was introduced into the side chain in the polymer molecule. Polyester film as a base material prepared by blending 1 part by weight of a polyisocyanate-based crosslinking agent and 3 parts by weight of an acetophenone-based photopolymerization initiator with respect to 100 parts by weight of the polymer into which the carbon-carbon double bond part is introduced. A pressure-sensitive adhesive sheet is formed by applying a pressure-sensitive adhesive layer on (thickness 100 μm) so that the thickness after drying is 150 μm, and only one side is a pressure-sensitive adhesive surface (when referred to as “pressure-sensitive adhesive sheet E”) Got).

  Therefore, the pressure-sensitive adhesive sheet E has a configuration in which a pressure-sensitive adhesive layer (energy ray-curable pressure-sensitive adhesive layer) is formed on one surface of the substrate.

(Example 1)
A pressure-sensitive adhesive provided on the base material via the intermediate layer of the double-sided pressure-sensitive adhesive sheet A on the surface (surface on which the bumps are formed) of the semiconductor wafer provided with bumps having a maximum unevenness of 100 μm on the surface After adhering the adhesive surface by the layers, a glass supporting wafer was bonded to the adhesive surface on the heat-peeling pressure-sensitive adhesive layer side to produce a reinforcing wafer (sometimes referred to as “reinforcing wafer A”).

(Example 2)
Energy curing provided on the base material via the intermediate layer of the double-sided pressure-sensitive adhesive sheet B on the surface (surface on which the bumps are formed) of the semiconductor wafer provided with bumps having a maximum unevenness of 100 μm on the surface. After adhering the adhesive surface with the mold adhesive layer, a glass supporting wafer was attached to the adhesive surface on the heat-peeling adhesive layer side to produce a reinforcing wafer (sometimes referred to as “reinforcing wafer B”). .

(Example 3)
By the adhesive layer provided on the base material via the intermediate layer of the adhesive sheet C on the surface (surface on which the bump is formed) of the semiconductor wafer provided with bumps having a maximum unevenness of 100 μm on the surface Adhesive surfaces were bonded together to produce a semiconductor wafer with a protective support sheet. Next, after bonding the heat-peelable pressure-sensitive adhesive sheet A obtained in the same manner as in Production Example 1 of the pressure-sensitive adhesive sheet to a glass support wafer, the back surface of the pressure-sensitive adhesive sheet C in the semiconductor wafer with the protective support sheet ( The base material side surface) and the back surface (base material side surface) of the heat-peelable pressure-sensitive adhesive sheet A bonded to the supporting wafer are bonded together using an adhesive, and a reinforcing wafer ("reinforcing wafer C") May be referred to).

(Comparative Example 1)
Provided on the base material via an intermediate layer in an adhesive sheet C as a protective support sheet on the surface (surface on which the bumps are formed) of the semiconductor wafer provided with bumps having a maximum unevenness of 100 μm on the surface. The pressure-sensitive adhesive layer was bonded together to produce a semiconductor wafer with a protective support sheet (sometimes referred to as “semiconductor wafer A with a protective support sheet”).

(Comparative Example 2)
Provided on the base material via the intermediate layer in the adhesive sheet D as a protective support sheet, on the surface (surface on which the bumps are formed) of the semiconductor wafer provided with bumps having a maximum unevenness of 100 μm on the surface. The pressure-sensitive adhesive layer was bonded together to produce a semiconductor wafer with a protective support sheet (sometimes referred to as “semiconductor wafer B with a protective support sheet”).

(Comparative Example 3)
By the pressure-sensitive adhesive layer provided on the substrate in the pressure-sensitive adhesive sheet E as a protective support sheet on the surface (surface on which the bumps are formed) of the semiconductor wafer provided with bumps having a maximum unevenness of 100 μm on the surface The pressure-sensitive adhesive surfaces were bonded together to produce a semiconductor wafer with a protective support sheet (sometimes referred to as “semiconductor wafer C with a protective support sheet”).

(Evaluation)
With respect to the reinforcing wafers A to C obtained in Examples 1 to 3 and the semiconductor wafers A to C with protective support sheets obtained in Comparative Examples 1 to 3, the semiconductor wafers were manufactured by a silicon wafer grinding machine manufactured by Disco Corporation. After grinding the back surface to a thickness of 50 μm, the semiconductor wafer is cracked by grinding at the time of grinding, the warpage of the semiconductor wafer is observed, the amount of warpage is obtained, and further the semiconductor wafer due to warpage The crack was confirmed. Regarding the cracking of the semiconductor wafer due to grinding and the cracking of the semiconductor wafer due to warping, if even one of the 10 wafers is cracked, it is evaluated as “Yes” and one of the 10 wafers is also broken. In the case where no cracks occurred, it was evaluated as “None”. The warpage amount of the semiconductor wafer was measured by grinding the semiconductor wafer after grinding in a state where the support wafer or the protective support sheet was bonded. These evaluation results are shown in each column of Table 1.

  As is clear from Table 1, as in Examples 1 to 3, when thin processing is performed with the semiconductor wafer bonded to the support via an adhesive sheet, the semiconductor wafer has a large unevenness on the surface. It was confirmed that even a semiconductor wafer on which a wiring pattern or a bump having the thin film can be processed without causing breakage or warpage.

It is a schematic process drawing which shows an example of the processing method of the semiconductor wafer of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor wafer 1a The surface (wiring pattern formation surface) of the semiconductor wafer 1
1b The back surface of the semiconductor wafer 1 (wiring pattern non-formed surface)
1c Bump 2 Double-sided adhesive sheet 2a Base material 2b Adhesive layer 2c Adhesive layer 2d Release liner 3 Support plate 4 Grinding machine (grinder)
5 Adhesive tape for dicing 5a Base material 5b Adhesive layer

Claims (9)

A method of processing a semiconductor wafer by applying a thin processing to a semiconductor wafer having a wiring pattern and / or bumps having a maximum unevenness of 0.1 to 350 μm formed on the surface, the semiconductor wafer being bonded via an adhesive sheet A method for processing a semiconductor wafer, comprising fixing a wafer to a support and performing thin processing. The adhesive sheet has an adhesive surface to be bonded to the semiconductor wafer, and after the thin processing of the semiconductor wafer, the adhesive force of the adhesive sheet bonded to the semiconductor wafer to the semiconductor wafer can be reduced. The semiconductor wafer processing method according to claim 1, wherein the semiconductor wafer has a possible configuration. The method for processing a semiconductor wafer according to claim 2, wherein the pressure-sensitive adhesive layer serving as the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet bonded to the semiconductor wafer is formed via an intermediate layer. The method for processing a semiconductor wafer according to claim 2 or 3, wherein the pressure-sensitive adhesive layer serving as the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet to be bonded to the semiconductor wafer is an energy ray curable pressure-sensitive adhesive layer or a heat-peelable pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet has a pressure-sensitive adhesive surface to be bonded to the support, and after the thin processing of the semiconductor wafer, the adhesive force of the pressure-sensitive adhesive sheet bonded to the support to the support can be reduced. The semiconductor wafer processing method according to claim 1, wherein the semiconductor wafer has a possible configuration. The method for processing a semiconductor wafer according to claim 5, wherein the pressure-sensitive adhesive layer serving as the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet bonded to the support is an energy ray-curable pressure-sensitive adhesive layer or a heat-peelable pressure-sensitive adhesive layer. After the thin processing of the semiconductor wafer, the surface subjected to the thin processing is mounted with a dicing adhesive tape or sheet, and the adhesive sheet used for fixing to the support is peeled from the semiconductor wafer. The method for processing a semiconductor wafer according to any one of items 6 to 6. The method for processing a semiconductor wafer according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive sheet used for fixing to the support is peeled off from the semiconductor wafer by peeling. A semiconductor wafer processing, characterized in that at least one surface is an adhesive sheet, and is an adhesive sheet used in the semiconductor wafer processing method according to any one of claims 1 to 8. Adhesive sheet.

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