JP2019047075A - Adhesive tape for semiconductor wafer protection - Google Patents

Abstract

To provide an adhesive tape for semiconductor wafer protection, which is hard to produce a crack in a semiconductor wafer in a back grinding step.SOLUTION: An adhesive tape for semiconductor wafer protection comprises: a base material; and a sticker layer laminated on the base material. The base material has a thickness of 10-150 μm at 23°C. The maximum increase rate of a thickness of the adhesive tape in a range of 23-100°C to the thickness of the adhesive tape at 23°C when the adhesive tape is heated from -70°C to 150°C with a 0.11 N-load applied thereto in a thickness direction by a compression expansion method of a thermomechanical analysis apparatus is 1.2% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adhesive tape for protecting a semiconductor wafer. More particularly, the present invention relates to a pressure-sensitive adhesive tape for protecting a semiconductor wafer, which is used when cutting the back surface of a semiconductor wafer.

  Conventionally, backgrind tapes may be used in the manufacture of semiconductor devices. The back grind tape has a form in which a pressure sensitive adhesive layer is provided on a base material, arranges a semiconductor wafer on the pressure sensitive adhesive layer, and holds the semiconductor wafer during back grinding (back grinding) of the semiconductor wafer. It is used for applications, applications for protecting the surface of semiconductor wafers, and applications for securing the separated semiconductor chips not to scatter if the semiconductor wafers are separated by back grinding (for example, see Patent Documents 1 to 3). ).

  In backgrind, usually, the front surface (front surface; surface on which a wiring structure necessary for a semiconductor element is formed) is disposed on the adhesive layer of backgrind tape, and the semiconductor wafer has a predetermined thickness from the back surface. The grinding process is performed until the semiconductor wafer is thinned.

  Also, in recent years, a method for obtaining individual semiconductor chips by forming grooves on the surface of a semiconductor wafer and thereafter performing back grinding (sometimes referred to as "DBG (Dicing Before Grinding)") or division in a semiconductor wafer After the semiconductor wafer can be easily divided at the planned dividing line by irradiating the planned line with laser light to form a modified region, back grinding is performed, and then the semiconductor wafer is attached to a dicing die bond film The semiconductor wafer and the die-bonding film are cut together (broken) by expanding the dicing tape at a low temperature (for example, −25 to 0 ° C.) (hereinafter sometimes referred to as “cool expanding”). Individual semiconductor chip (semiconductor chip with die bond film Methods have been proposed. This is a method called so-called "SDBG (Stealth Dicing Before Grinding)".

JP, 2011-054940, A Unexamined-Japanese-Patent No. 2015-185691 JP 2005-343997 A

  In recent years, thinning of silicon layers has progressed due to the need for higher capacity of semiconductors. For this reason, the technique for obtaining a semiconductor wafer thinner than before by back grinding has become necessary. In the back grinding step for obtaining such a semiconductor wafer thinner than the conventional one, main grinding for thinning the semiconductor wafer and post-grinding for improving the smoothness of the ground surface after the main grinding are performed.

  However, in such a back grinding process for obtaining a semiconductor wafer thinner than before, there is a problem that a crack (crack) is easily generated in the semiconductor wafer in the main grinding and the post-polishing. In particular, cracking was likely to occur in the back grinding process when using a semiconductor wafer in which a modified region was formed by laser light irradiation.

  The present invention was made in view of the above problems, and the present inventors focused on a back grind tape and aimed to develop an adhesive tape which is less likely to cause a crack in a semiconductor wafer in a back grind process. Therefore, an object of the present invention is to provide a pressure-sensitive adhesive tape for protecting a semiconductor wafer which is less likely to cause a crack in a semiconductor wafer in a back grinding process.

  The inventors of the present invention conducted intensive studies to achieve the above object, and as a result, a pressure-sensitive adhesive tape for semiconductor wafer protection comprising a substrate and a pressure-sensitive adhesive layer laminated on the substrate. The thickness of the material is 10 to 150 μm, and the adhesive tape is heated from -70 ° C to 150 ° C at a load of 0.11 N in the thickness direction according to the compression expansion method of the thermomechanical analyzer, 23 ° C When a pressure-sensitive adhesive tape for protecting a semiconductor wafer has a maximum increase of 1.2% or less in the thickness of the pressure-sensitive adhesive tape at 23 to 100 ° C. with respect to the thickness of the pressure-sensitive adhesive tape, cracks occur in the semiconductor wafer in the back grinding step. I found it difficult. The present invention has been completed based on these findings.

  That is, the present invention is a pressure-sensitive adhesive tape for semiconductor wafer protection, comprising a substrate and a pressure-sensitive adhesive layer laminated on the substrate, wherein the thickness of the substrate at 23 ° C. is 10 to 150 μm. 23-100 relative to the thickness of the pressure-sensitive adhesive tape at 23 ° C. when the pressure-sensitive adhesive tape is heated from −70 ° C. to 150 ° C. with a load of 0.11 N applied in the thickness direction by the compressive expansion method of a mechanical analyzer. The adhesive tape for semiconductor wafer protection whose maximum increase rate of the thickness of the said adhesive tape in ° C is 1.2% or less is provided.

  The adhesive tape for protecting a semiconductor wafer according to the present invention has a thickness of 10 to 150 μm of the base material at 23 ° C. and a load of 0.11 N applied in the thickness direction by the compression and expansion method of the thermomechanical analyzer. Maximum increase rate of the thickness of the adhesive tape at 23 to 100 ° C with respect to the thickness of the adhesive tape at 23 ° C when the adhesive tape is heated from -70 ° C to 150 ° C (sometimes referred to as "maximum expansion coefficient" Even if the pressure-sensitive adhesive tape is heated up to about 100 ° C. in the back grinding process which makes the semiconductor wafer thinner than before by setting the) to 1.2% or less, the thickness of the pressure-sensitive adhesive tape is The thermal expansion is small and the stress from the adhesive tape to the semiconductor wafer is small. Be a semiconductor wafer which weakened region is formed, a crack is unlikely to occur.

  The pressure-sensitive adhesive tape for protecting a semiconductor wafer according to the present invention comprises, as the pressure-sensitive adhesive layer, at least a pressure-sensitive adhesive layer having a loss coefficient (tan δ) of 1.0 or more under the conditions of 25 ° C. and 100 Hz frequency. It is preferable to have one layer. Although sticking of the adhesive tape to the semiconductor wafer is usually performed using a laminating apparatus, in this case, it is practically impossible to apply without completely applying tension, so the adhesive tape after sticking is attached Sometimes the tension applied is accumulated as residual stress. Due to this residual stress, for example, in the back grinding process, a crack tends to be easily generated due to collisions between the regions (the regions corresponding to the semiconductor chips after singulation) of the semiconductor wafer with the modification region as a trigger. There is. On the other hand, when the pressure-sensitive adhesive tape for protecting a semiconductor wafer of the present invention has a pressure-sensitive adhesive layer having the above-mentioned loss coefficient (tan δ) of 1.0 or more, residual stress is easily dispersed and dissipated early (stress relaxation). Since the semiconductor wafer is easily damped, it is difficult for the semiconductor wafer to be stressed and less likely to cause a crack.

  The adhesive tape for protecting a semiconductor wafer of the present invention is less likely to cause a crack in a semiconductor wafer in a back grinding process. In particular, even in the case of using a semiconductor wafer in which a weakened region such as a modified region is formed, it is difficult to cause a crack.

It is a cross-sectional schematic diagram which shows one Embodiment of the adhesive tape for semiconductor wafer protection of this invention. It is a cross-sectional schematic diagram which shows other one Embodiment of the adhesive tape for semiconductor wafer protection of this invention. The process shows a part of the process for producing a semiconductor device using the adhesive tape for protecting a semiconductor wafer according to the present invention. The process shows a part of the process for producing a semiconductor device using the adhesive tape for protecting a semiconductor wafer according to the present invention. The process shows a part of the process for producing a semiconductor device using the adhesive tape for protecting a semiconductor wafer according to the present invention. It is a graph which shows the expansion coefficient with respect to the thickness of 23 degreeC in the range of 23-100 degreeC measured by the compression expansion method of the thermomechanical analyzer about the adhesive tape of Example 1. FIG. It is a graph which shows the expansion coefficient with respect to the thickness of 23 degreeC in the range of 23-100 degreeC measured by the compression expansion method of the thermomechanical analyzer about the adhesive tape of Example 2. FIG. It is a graph which shows the expansion coefficient with respect to the thickness of 23 degreeC in the range of 23-100 degreeC measured by the compression expansion method of the thermomechanical analyzer about the adhesive tape of Example 3. FIG. It is a graph which shows the expansion coefficient with respect to the thickness of 23 degreeC in the range of 23-100 degreeC measured by the compression expansion method of the thermomechanical analyzer about the adhesive tape of Example 4. FIG. It is a graph which shows the expansion coefficient with respect to the thickness of 23 degreeC in the range of 23-100 degreeC measured by the compression expansion method of the thermomechanical analyzer about the adhesive tape of Example 5. FIG. It is a graph which shows the expansion coefficient with respect to the thickness of 23 degreeC in the range of 23-100 degreeC measured by the compression expansion method of the thermomechanical analyzer about the adhesive tape of Example 6. FIG. It is a graph which shows the expansion coefficient with respect to the thickness of 23 degreeC in the range of 23-100 degreeC measured by the compression expansion method of the thermomechanical analyzer about the adhesive tape of the comparative example 1. FIG. It is a graph which shows the coefficient of expansion with respect to the thickness of 23 degreeC in the range of 23-100 degreeC measured by the compression expansion method of the thermomechanical analyzer about the adhesive tape of the comparative example 2. FIG.

[Adhesive tape for semiconductor wafer protection]
The pressure-sensitive adhesive tape for protecting a semiconductor wafer according to the present invention has the other surface (particularly, the surface) of the semiconductor wafer on the pressure-sensitive adhesive layer when the semiconductor wafer is thinned by grinding one surface (particularly the back surface) of the semiconductor wafer. It is preferable to use for the application which sticks and hold | maintains a semiconductor wafer.

  The adhesive tape for semiconductor wafer protection of the present invention has a substrate and an adhesive layer laminated on the above-mentioned substrate.

  As described above, in the pressure-sensitive adhesive tape for semiconductor wafer protection of the present invention, the thickness of the substrate at 23 ° C. is 10 to 150 μm, preferably 25 to 100 μm. When the thickness is in the above range, the semiconductor wafer is less likely to be cracked when the maximum increase rate of the adhesive tape for protecting a semiconductor wafer is 1.2% or less.

  The adhesive tape for protecting a semiconductor wafer according to the present invention is, as described above, a pressure-sensitive adhesive tape for protecting a semiconductor wafer under a load of 0.11 N in the thickness direction by the compression and expansion method of the thermomechanical analyzer. The maximum increase rate (maximum expansion rate) of the adhesive tape for semiconductor wafer protection at 23 to 100 ° C with respect to the thickness of the adhesive tape for semiconductor wafer protection at 23 ° C when heated to 23 ° C is 1.2% or less, Is less than 1.1%, more preferably less than 1.0%. Even if the pressure-sensitive adhesive tape is heated up to about 100 ° C. in the back grinding process in which the semiconductor wafer is made thinner than before because the maximum increase rate is 1.2% or less, the thickness of the pressure-sensitive adhesive tape Since the thermal expansion with respect to normal temperature is small and the stress from the adhesive tape to the semiconductor wafer is small, it goes without saying that when a normal semiconductor wafer is used, it is a semiconductor wafer in which a weakened area such as a modified area is formed, Less likely to crack. The maximum increase rate may be a negative number, but the lower limit is, for example, -10%.

The said maximum increase rate is calculated | required by the measuring method of the following maximum increase rates.
<Method of measuring the maximum increase rate>
A strip-shaped test piece is obtained by cutting out from the adhesive tape for protecting a semiconductor wafer. The strip-shaped test piece is set in a thermomechanical analyzer, and the strip-shaped test piece is heated from -70 ° C to 150 ° C by the compression expansion method of the thermomechanical analyzer, and the thickness displacement at that time is measured . The thickness of the strip-shaped test piece at 23 ° C. is A, and the maximum thickness of the strip-shaped test piece at 23 to 100 ° C. is B, which is determined by the following equation.
Maximum increase rate (%) = (B-A) / A x 100

(Base material)
The substrate is an element that functions as a support in the adhesive tape for protecting a semiconductor wafer of the present invention. As said base material, a plastic base material (especially plastic film) is mentioned, for example. The substrate may be a single layer, or a laminate of similar or different substrates. In the present specification, a single layer means a layer having the same composition, and includes a form in which a plurality of layers having the same composition are stacked.

  Examples of the resin constituting the plastic base include low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypropylene , Polybutene, polymethylpentene, ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene- Polyolefin resins such as butene copolymer, ethylene-hexene copolymer; polyurethane; polyester such as polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate (PBT); polycarbonate; polyimide; Polyetheretherketone; polyetherimides; aramid, polyamide such as wholly aromatic polyamide; polyphenyl sulfide; fluorine resin, polyvinyl chloride, polyvinylidene chloride, cellulose resin, silicone resin, and the like. The said resin may be used only by 1 type, and 2 or more types may be used. When the pressure-sensitive adhesive layer is a radiation-curable type as described later, it is preferable that the substrate has radiation transparency.

  The surface on the pressure-sensitive adhesive layer side of the substrate is, for example, corona discharge treatment, plasma treatment, sand mat processing, ozone exposure treatment, flame exposure treatment, high-piezoelectric shock treatment, for the purpose of enhancing adhesion and retention with the pressure-sensitive adhesive layer. Physical treatments such as exposure treatment and ionizing radiation treatment; chemical treatments such as chromic acid treatment; and surface treatments such as easy adhesion treatment with a coating agent (primer) may be applied. Moreover, in order to provide antistatic ability, you may provide the conductive vapor deposition layer containing a metal, an alloy, these oxides, etc. on the base-material surface.

(Pressure-sensitive adhesive layer)
The adhesive tape for protecting a semiconductor wafer of the present invention has at least one adhesive layer on a substrate. The pressure-sensitive adhesive layer may be a single layer, or may be a laminate of the same or different pressure-sensitive adhesive layers.

  The pressure-sensitive adhesive tape for semiconductor wafer protection of the present invention comprises, as the pressure-sensitive adhesive layer, at least one pressure-sensitive adhesive layer having a loss coefficient (tan δ) of 1.0 or more under the conditions of 25 ° C. and 100 Hz frequency. It is preferable to have. Although sticking of the adhesive tape to the semiconductor wafer is usually performed using a laminating apparatus, in this case, it is practically impossible to apply without completely applying tension, so the adhesive tape after sticking is attached Sometimes the tension applied is accumulated as residual stress. Due to this residual stress, for example, in the back grinding process, a crack tends to be easily generated due to collisions between the regions (the regions corresponding to the semiconductor chips after singulation) of the semiconductor wafer with the modification region as a trigger. There is. On the other hand, when the pressure-sensitive adhesive tape for protecting a semiconductor wafer of the present invention has a pressure-sensitive adhesive layer having the above-mentioned loss coefficient (tan δ) of 1.0 or more, residual stress is easily dispersed and dissipated early (stress relaxation). Since the semiconductor wafer is easily damped, it is difficult for the semiconductor wafer to be stressed and less likely to cause a crack. The upper limit of the loss factor is, for example, 5.0. Moreover, in the present specification, the pressure-sensitive adhesive layer having the loss coefficient of 1.0 or more may be referred to as “pressure-sensitive adhesive layer X”.

The said loss coefficient is a value obtained by subjecting the adhesive layer in the adhesive tape for semiconductor wafer protection to a nanoindentation test. In the nanoindentation test, the load applied to the indenter and the indentation depth when the indenter is pressed into the adhesive layer are continuously measured during loading and unloading, and the obtained load-indentation depth curve The storage elastic modulus and the loss elastic modulus are calculated from the above, and the loss elastic modulus / storage elastic modulus is calculated as the above-mentioned loss coefficient (loss tangent). The loss coefficient by the nanoindentation method of the said adhesive layer is measured on condition of the following.
Measuring device (nano indenter): Hysitron Inc. Made, Triboindenter
Indenter: Berkovich (triangular pyramid)
Measurement method: Dynamic measurement Indentation depth setting: 500 nm
Frequency: 100Hz
Amplitude: 2 nm

  When the pressure-sensitive adhesive tape for semiconductor wafer protection of the present invention has a laminate of pressure-sensitive adhesive layers and has a pressure-sensitive adhesive layer X, at least one of the pressure-sensitive adhesive layers in the laminate is the pressure-sensitive adhesive layer X Although it is sufficient, the pressure-sensitive adhesive layer located at least on the outermost surface (the outermost surface opposite to the base material) of the laminate is preferably the pressure-sensitive adhesive layer X, and all the adhesives constituting the laminate More preferably, the layer is an adhesive layer X.

  With regard to the loss coefficient, the loss coefficient of the pressure-sensitive adhesive layer in the case where the pressure-sensitive adhesive layer X is the pressure-sensitive adhesive layer located on the outermost surface is more preferably 1.1 or more, and still more preferably 1.15 or more. On the other hand, when the pressure-sensitive adhesive layer X is a pressure-sensitive adhesive layer located inside the pressure-sensitive adhesive tape (that is, a pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer located on the outermost surface), the above-mentioned loss coefficient of the pressure-sensitive adhesive layer is 1. 0 or more is preferable.

  The above-mentioned adhesive layer which the adhesive tape for semiconductor wafer protection of the present invention has is formed of an adhesive. The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer may be a pressure-sensitive adhesive (pressure-sensitive adhesive with reduced adhesive strength) capable of intentionally reducing the adhesive strength by an action from the outside such as radiation irradiation. The adhesive may be a pressure-sensitive adhesive (adhesive force non-reduction type pressure-sensitive adhesive) with little or no decrease in adhesive force depending on the action of the adhesive, and it may be appropriately selected according to the type of semiconductor wafer to be attached Can be selected.

  In the case of using a pressure-sensitive adhesive as the pressure-sensitive adhesive, the pressure-sensitive adhesive layer exhibits relatively high adhesion and relatively low adhesion in the process of producing or using the pressure-sensitive adhesive tape for protecting a semiconductor wafer of the present invention. It becomes possible to use properly the state which shows power. For example, when bonding a semiconductor wafer to be back ground in the back grinding step to the pressure sensitive adhesive layer of the pressure sensitive adhesive tape for protecting a semiconductor wafer of the present invention, or during back grinding, the pressure sensitive adhesive layer has relatively high adhesion. While it becomes possible to suppress and prevent floating of the semiconductor wafer and the separated semiconductor chips from the adhesive layer using the state shown, it is possible to use the back ground semiconductor wafer or the separated semiconductor chips thereafter. When the pressure-sensitive adhesive tape for protecting a semiconductor wafer of the present invention is peeled off, peeling can be easily performed by reducing the adhesive strength of the pressure-sensitive adhesive layer. Therefore, in the adhesive tape for protection of a semiconductor wafer of the present invention, the pressure-sensitive adhesive layer in which the pressure-sensitive adhesive layer located on the outermost surface (the outermost surface opposite to the substrate) is formed of a pressure-sensitive adhesive It is preferable that it is the below-mentioned radiation-curable pressure-sensitive adhesive layer).

  Examples of such an adhesive force-reducing pressure-sensitive adhesive include a radiation-curable pressure-sensitive adhesive (a pressure-sensitive adhesive having a radiation-curable property) and the like. As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, one kind of pressure-sensitive adhesive may be used, or two or more kinds of pressure-sensitive adhesive may be used. In addition, the whole of the pressure-sensitive adhesive layer may be formed of a pressure-sensitive adhesive, or a part of the pressure-sensitive adhesive may be formed of a pressure-sensitive adhesive.

  As the radiation-curable pressure-sensitive adhesive, for example, a pressure-sensitive adhesive of a type which can be cured by irradiation of electron beam, ultraviolet light, α-ray, β-ray, γ-ray or X-ray can be used. A pressure-sensitive adhesive (ultraviolet-curable pressure-sensitive adhesive) can be particularly preferably used.

  As the radiation-curable pressure-sensitive adhesive, a pressure-sensitive adhesive containing any appropriate acrylic polymer can be used. Preferably, an acrylic polymer having at least one radiation polymerizable functional group (for example, a functional group having a carbon-carbon multiple bond such as acryloyl group, methacryloyl group, vinyl group, allyl group and ethynyl group) and photopolymerization initiation A pressure-sensitive adhesive (internal-type radiation-curable pressure-sensitive adhesive) containing an agent is used. Alternatively, a pressure-sensitive adhesive (addition type radiation-curable pressure-sensitive adhesive) containing an acrylic polymer, a radiation-polymerizable monomer component and / or a radiation-polymerizable oligomer component, and a photopolymerization initiator may be used. When the intrinsic type radiation-curable pressure-sensitive adhesive is used, there is a tendency to be able to suppress an unintended change with time of the pressure-sensitive adhesive property due to the movement of the low molecular weight component in the formed pressure-sensitive adhesive layer.

  The said acryl-type polymer is a polymer containing the structural unit derived from an acryl-type monomer (The monomer component which has a (meth) acryloyl group in a molecule | numerator) as a structural unit of a polymer. It is preferable that the said acryl-type polymer is a polymer which contains the structural unit originating in a (meth) acrylic acid ester most by mass ratio. In addition, an acryl-type polymer may use only 1 type, and may use 2 or more types. Further, in the present specification, “(meth) acrylic” represents “acrylic” and / or “methacrylic” (any one or both of “acrylic” and “methacrylic”), and the same applies to others. .

  As said (meth) acrylic acid ester, hydrocarbon group containing (meth) acrylic acid esters, such as (meth) acrylic acid alkyl ester, (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid aryl ester, are mentioned, for example Be Examples of the (meth) acrylic acid alkyl ester include methyl ester of (meth) acrylic acid, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, Isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester , Octadecyl ester, eicosyl ester and the like. Examples of the (meth) acrylic acid cycloalkyl ester include cyclopentyl ester and cyclohexyl ester of (meth) acrylic acid. Examples of the (meth) acrylic acid aryl ester include phenyl ester of (meth) acrylic acid and benzyl ester. The above (meth) acrylic acid esters may be used alone or in combination of two or more. In order to properly express basic properties such as adhesiveness by (meth) acrylic acid ester in the pressure-sensitive adhesive layer, the proportion of (meth) acrylic acid ester in all monomer components for forming an acrylic polymer is 40 mass % Or more is preferable, More preferably, it is 60 mass% or more.

  The said acryl-type polymer may contain the structural unit derived from the other monomer component which can be copolymerized with the said (meth) acrylic acid ester for the purpose of modification, such as cohesion force and heat resistance. Examples of the other monomer components include carboxy group-containing monomers, acid anhydride monomers, hydroxy group-containing monomers, epoxy group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, acrylamide, acryloyl morpholine, Examples include amino group-containing monomers, cyano group-containing monomers (acrylonitrile and the like), keto group-containing monomers, monomers having a nitrogen atom-containing ring, and functional group-containing monomers such as alkoxysilyl group-containing monomers. Examples of the carboxy group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and the like. Examples of the acid anhydride monomer include maleic anhydride, itaconic anhydride and the like. Examples of the above-mentioned hydroxy group-containing monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, Examples thereof include 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate. Examples of the epoxy group-containing monomer include glycidyl group-containing monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate. Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamido-2-methylpropane sulfonic acid, (meth) acrylamidopropane sulfonic acid, sulfopropyl (meth) acrylate, (meth Acryloyloxy naphthalene sulfonic acid etc. are mentioned. As said phosphoric acid group containing monomer, 2-hydroxyethyl acryloyl phosphate etc. are mentioned, for example. The other monomer components may be used alone or in combination of two or more. In order to properly express in the adhesive layer 12 basic characteristics such as adhesiveness by (meth) acrylic acid ester, the proportion of the other monomer components in all the monomer components for forming the acrylic polymer is 60 mass % Or less is preferable, More preferably, it is 40 mass% or less.

  The above acrylic polymer is a structural unit derived from a polyfunctional monomer copolymerizable with a monomer component forming the above acrylic polymer such as (meth) acrylic acid ester to form a crosslinked structure in the polymer skeleton thereof May be included. Examples of the polyfunctional monomer include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, penta Erythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate (eg, polyglycidyl (meth) acrylate), polyester The monomer etc. which have a (meth) acryloyl group and other reactive functional groups in the molecule | numerator of (meth) acrylate, urethane (meth) acrylate, etc. are mentioned. The polyfunctional monomers may be used alone or in combination of two or more. In order to appropriately express basic properties such as adhesiveness by (meth) acrylate in the adhesive layer, the proportion of the above-mentioned polyfunctional monomer in all monomer components for forming an acrylic polymer is 40% by mass The following are preferable, More preferably, it is 30 mass% or less.

  The acrylic polymer is obtained by subjecting one or more monomer components containing an acrylic monomer to polymerization. As a polymerization method, solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like can be mentioned.

  The weight-average molecular weight of the acrylic polymer in the pressure-sensitive adhesive layer is preferably 200,000 to 3,000,000, and more preferably 250,000 to 1,500,000. When the weight average molecular weight is 200,000 or more, the amount of low molecular weight substances in the adhesive layer tends to be small, and when peeling the adhesive tape for protecting a semiconductor wafer of the present invention, the adhesive to a semiconductor wafer or an individualized semiconductor chip etc. The rest can be suppressed.

  The pressure-sensitive adhesive may contain a crosslinking agent. For example, when an acrylic polymer is used as the base polymer, the acrylic polymer can be crosslinked to improve the degree of crosslinking of the pressure-sensitive adhesive layer, and the maximum increase rate tends to be small. As said crosslinking agent, a polyisocyanate compound, an epoxy compound, a polyol compound (polyphenol type compound etc.), an aziridine compound, a melamine compound etc. are mentioned, for example. When a crosslinking agent is used, the amount thereof is preferably about 20 parts by mass or less with respect to 100 parts by mass of the base polymer, because the loss coefficient tends to decrease when the degree of crosslinking of the pressure-sensitive adhesive layer becomes too high. More preferably, it is 0.1-10 mass parts, More preferably, it is 0.6-8 mass parts.

  As the radiation polymerizable monomer component and / or the radiation polymerizable oligomer component, it is a photoreactive compound having a functional group having a carbon-carbon multiple bond such as acryloyl group, methacryloyl group, vinyl group, allyl group and ethynyl group. Monomers or oligomers may be mentioned. Examples of the radiation polymerizable monomer component include urethane (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxy penta ( Examples include meta) acrylate, dipentaerythritol hexa (meth) acrylate, and 1,4-butanediol di (meth) acrylate. Examples of the radiation polymerizable oligomer component include various oligomers such as urethane type, polyether type, polyester type, polycarbonate type and polybutadiene type, and those having a molecular weight of about 100 to 30,000 are preferable. The content of the radiation curable monomer component and the oligomer component in the adhesive forming the adhesive layer is, for example, about 5 to 500 parts by mass, preferably about 40 to 150 parts by mass with respect to 100 parts by mass of the base polymer. It is. In addition, as the addition type radiation-curable pressure-sensitive adhesive, for example, those disclosed in JP-A-60-196956 may be used.

  As a method of introducing a radiation-polymerizable carbon-carbon multiple bond into an acrylic polymer, for example, after polymerizing (copolymerizing) a raw material monomer containing a monomer component having a first functional group to obtain an acrylic polymer A compound having a second functional group capable of reacting with the first functional group and a radiation-polymerizable carbon-carbon multiple bond with respect to an acrylic polymer while maintaining the radiation-polymerizable carbon-carbon multiple bond A condensation reaction or an addition reaction may be mentioned.

  Examples of combinations of the first functional group and the second functional group include a carboxy group and an epoxy group, an epoxy group and a carboxy group, a carboxy group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, An isocyanate group, a hydroxy group, etc. are mentioned. Among these, the combination of a hydroxy group and an isocyanate group and the combination of an isocyanate group and a hydroxy group are preferable from the viewpoint of easiness of reaction tracking. Among them, it is technically difficult to produce a polymer having a highly reactive isocyanate group, while the first functional group is preferably from the viewpoint of the ease of preparation and availability of an acrylic polymer having a hydroxy group. The combination which is a hydroxyl group and whose said 2nd functional group is an isocyanate group is preferable. Examples of the compound having an isocyanate group and a radiation-polymerizable carbon-carbon double bond in this case include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate and the like. . Moreover, as an acrylic polymer having a hydroxy group, one comprising a constitutional unit derived from the above-mentioned hydroxy group-containing monomer, or an ether compound such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether or diethylene glycol monovinyl ether Can be mentioned.

  Examples of the photopolymerization initiator include α-ketol compounds, acetophenone compounds, benzoin ether compounds, ketal compounds, aromatic sulfonyl chloride compounds, photoactive oxime compounds, benzophenone compounds, thioxanthone compounds, Examples include camphor quinone, halogenated ketones, acyl phosphinoxides, and acyl phosphonates. Examples of the above α-ketol compounds include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxy Propiophenone, 1-hydroxycyclohexyl phenyl ketone and the like can be mentioned. Examples of the above acetophenone compounds include methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2 -Morpholinopropane-1, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one and the like. Examples of the above-mentioned benzoin ether compound include benzoin ethyl ether, benzoin isopropyl ether, anisoin methyl ether and the like. Examples of the ketal compounds include benzyl dimethyl ketal and the like. As said aromatic sulfonyl chloride type compound, 2-naphthalene sulfonyl chloride etc. are mentioned, for example. Examples of the photoactive oxime compounds include 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime and the like. Examples of the benzophenone compounds include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone and the like. Examples of the thioxanthone compounds include thioxanthone, 2-chlorothioxanthone, 2-methyl thioxanthone, 2,4-dimethyl thioxanthone, isopropyl thioxanthone, 2,4-dichloro thioxanthone, 2,4-diethyl thioxanthone, 2,4-diisopropyl Thioxanthone etc. are mentioned. The content of the photopolymerization initiator in the radiation-curable pressure-sensitive adhesive is, for example, 0.05 to 20 parts by mass with respect to 100 parts by mass of the base polymer.

  Examples of the non-adhesive force reducing type pressure-sensitive adhesive include pressure-sensitive adhesives in which radiation curing type pressure-sensitive adhesives described above with respect to the pressure-sensitive adhesive type pressure-sensitive adhesive are previously cured by radiation irradiation, and pressure-sensitive pressure-sensitive adhesive. As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, one kind of non-adhesive force reducing type pressure-sensitive adhesive may be used, or two or more kinds of non-adhesive force non-reducing type pressure-sensitive adhesive may be used. In addition, the entire pressure-sensitive adhesive layer may be formed of a non-adhesive force reducing type adhesive, or a part may be formed of a non-adhesive force reducing type adhesive. For example, when the pressure-sensitive adhesive layer has a laminated structure, all the pressure-sensitive adhesive layers in the laminated structure may be formed of a non-adhesive force reducing type pressure-sensitive adhesive, or some adhesive layers in the laminated structure have non-adhesiveness. It may be formed of a reduced pressure sensitive adhesive.

  As the pressure-sensitive adhesive, known or commonly used pressure-sensitive adhesives can be used, and acrylic pressure-sensitive adhesives having an acrylic polymer as a base polymer, rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives and the like can be mentioned. When the pressure-sensitive adhesive layer contains an acrylic polymer as a pressure-sensitive adhesive, the acrylic polymer is preferably a polymer containing a constituent unit derived from (meth) acrylic acid ester as the largest constituent unit in mass ratio . As said acrylic polymer, the acrylic polymer demonstrated as an acrylic polymer contained in the above-mentioned radiation-curable adhesive can be employ | adopted, for example.

  The pressure-sensitive adhesive forming the above-mentioned pressure-sensitive adhesive layer or the above-mentioned pressure-sensitive adhesive layer is not only the above-mentioned components but also known or commonly used adhesion such as a crosslinking accelerator, tackifier, antiaging agent, coloring agent (pigment, dye, etc.) Additives used in the agent layer may be blended. As said coloring agent, the compound colored by irradiation with radiation is mentioned, for example. When it contains a compound that is colored by irradiation, only the irradiated part can be colored. The compound to be colored by the irradiation with radiation is a compound which is colorless or pale before irradiation with radiation but turns to a color by irradiation with radiation, and examples thereof include leuco dyes and the like. The amount of the compound to be colored by the above radiation irradiation is not particularly limited and can be appropriately selected.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited, but it is preferably 1 to 100 μm, more preferably 2 to 80 μm, and still more preferably 3 to 70 μm from the viewpoint of balancing the holding power of the semiconductor wafer and the maximum increase rate. . When the pressure-sensitive adhesive layer is a laminate of pressure-sensitive adhesive layers, the thickness of the pressure-sensitive adhesive layer is the thickness of the laminate.

  One embodiment of the adhesive tape for semiconductor wafer protection of the present invention is described below. FIG. 1 is a schematic cross-sectional view showing an embodiment of a pressure-sensitive adhesive tape for protecting a semiconductor wafer of the present invention in which the pressure-sensitive adhesive layer is constituted of a single layer.

  As shown in FIG. 1, the adhesive tape 1 for protecting a semiconductor wafer includes a substrate 11 and a single-layer pressure-sensitive adhesive layer 12 laminated on the substrate 11. Thus, when the pressure-sensitive adhesive layer is a single layer, the pressure-sensitive adhesive layer is a radiation-curable pressure-sensitive adhesive layer which is the pressure-sensitive adhesive layer X (that is, a radiation-curable pressure-sensitive adhesive layer having the above-mentioned loss coefficient of 1.0 or more) Is preferred. In the pressure-sensitive adhesive tape 1 for protecting a semiconductor wafer having such a configuration, the stress generated by the thermal expansion caused by the temperature rise of the pressure-sensitive adhesive tape is easily relieved in the pressure-sensitive adhesive layer 12. Even in a semiconductor wafer having a weakened area such as a modified area formed, cracks are less likely to occur, and separation and scattering of the semiconductor wafer or semiconductor chip can be suppressed or prevented in the back grinding process. On the other hand, when peeling from the semiconductor wafer or the semiconductor chip, peeling can be easily performed by reducing the adhesion of the pressure-sensitive adhesive layer by radiation irradiation.

  In addition, another embodiment of the adhesive tape for semiconductor wafer protection of the present invention will be described below. FIG. 2 is a schematic cross-sectional view showing an embodiment of a pressure-sensitive adhesive tape for protecting a semiconductor wafer of the present invention in which the pressure-sensitive adhesive layer is composed of multiple layers (that is, having a laminate of pressure-sensitive adhesive layers).

  As shown in FIG. 2, the adhesive tape 2 for protecting a semiconductor wafer includes a base 21 and a pressure-sensitive adhesive layer 22 laminated on the base 21. The pressure-sensitive adhesive layer 22 is a laminate of a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive layer 22a and a pressure-sensitive adhesive layer 22b. In addition, the adhesive layer 22b may be comprised by either a single | mono layer or multiple layers. Thus, when the pressure-sensitive adhesive layer is a laminate of pressure-sensitive adhesive layers, the pressure-sensitive adhesive layer 22a located on the outermost surface is a radiation-curable pressure-sensitive adhesive layer that is the pressure-sensitive adhesive layer X The above-mentioned radiation-curable pressure-sensitive adhesive layer), and the pressure-sensitive adhesive layer 22b located inside is the pressure-sensitive adhesive layer X that is the pressure-sensitive adhesive layer X (that is, the above-mentioned loss coefficient is 1.0 or more) It is preferable that it is an adhesive force non-reduction type adhesive layer). The adhesive tape 2 for protecting a semiconductor wafer having such a configuration can be easily adjusted to the above-mentioned maximum increase rate as the adhesive tape for protecting a semiconductor wafer within a specific range by the adhesive layer 22 b inside, and stress on the adhesive layer 22 b By imparting relaxation properties, stress is less likely to be applied to the semiconductor wafer, and cracking is less likely to occur. And the above-mentioned effect by using a radiation curing type pressure sensitive adhesive layer by pressure sensitive adhesive layer 22a of the outermost surface can be produced.

  When the pressure-sensitive adhesive layer located on the outermost surface of the laminate of the pressure-sensitive adhesive layer is a radiation-curable pressure-sensitive adhesive layer as in the pressure-sensitive adhesive layer 22a, the thickness of the pressure-sensitive adhesive layer is preferably 1 to 30 μm, more preferably Is 2 to 15 μm. In addition, as in the pressure-sensitive adhesive layer 22b, the thickness of the pressure-sensitive adhesive layer located inside the laminate of the pressure-sensitive adhesive layer (total thickness of the pressure-sensitive adhesive layer excluding the pressure-sensitive adhesive layer located on the outermost surface) is 10 to 100 μm Preferably it is 20-80 micrometers more preferably. With such a thickness design, the adhesive tape 2 for protecting a semiconductor wafer has the above-described effect of using a radiation-curable pressure-sensitive adhesive layer by the adhesive layer 22a on the outermost surface, while being relatively relatively thick in the thickness direction The above-mentioned maximum increase rate of the adhesive tape for semiconductor wafer protection can be easily adjusted to a specific range by the internal adhesive layer 22b which occupies a large portion. As a result, while being able to be easily peeled off from the semiconductor wafer or the semiconductor chip by the radiation irradiation, it is possible to make the crack more difficult to occur in the back grinding step.

  The adhesive tape 1 for semiconductor wafer protection which is one Embodiment of the adhesive tape for semiconductor wafer protection of this invention is manufactured as follows, for example. First, the substrate 11 can be obtained by film formation by a known or commonly used film formation method. Examples of the film forming method include a calendar film forming method, a casting method in an organic solvent, an inflation extrusion method in a closed system, a T-die extrusion method, a coextrusion method, a dry lamination method and the like.

  Next, a composition (pressure-sensitive adhesive composition) for forming the pressure-sensitive adhesive layer 12 containing the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer 12 and a solvent is coated on the substrate 11 to form a coated film, The adhesive film 12 can be formed by solidifying the coating film by solvent removal, curing or the like as necessary. Examples of the method of application include known or commonly used application methods such as roll coating, screen coating, and gravure coating. Moreover, as desolvation conditions, for example, the temperature is 80 to 150 ° C., and the time is for 0.5 to 5 minutes. Moreover, after apply | coating an adhesive composition on a separator and forming a coating film, a coating film may be solidified on said desolving conditions, and the adhesive layer 12 may be formed. Thereafter, the pressure-sensitive adhesive layer 12 is attached to the substrate 11 together with the separator. The adhesive tape 1 for semiconductor wafer protection can be produced as mentioned above.

  Moreover, the adhesive tape 2 for semiconductor wafer protection which is other one Embodiment of the adhesive tape for semiconductor wafer protection of this invention is manufactured as follows, for example. First, the form which has adhesive layer 22b on the base material 21 can be produced by the method similar to the above-mentioned adhesive tape 1 for semiconductor wafer protection. Then, similarly to the method for forming the pressure-sensitive adhesive layer 12 described above, a composition (pressure-sensitive adhesive composition) for forming the pressure-sensitive adhesive layer 22a including the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer 22a and the solvent is provided on the separator. After coating to form a coating film, the coating film may be solidified by solvent removal, curing or the like as necessary to form the pressure-sensitive adhesive layer 22a. Thereafter, the pressure-sensitive adhesive layer 22a is attached to the pressure-sensitive adhesive layer 22b together with the separator. As described above, the adhesive tape 2 for semiconductor wafer protection can be manufactured.

  As described above, for example, the adhesive tapes 1 and 2 for semiconductor wafer protection can be manufactured. In the adhesive tapes 1 and 2 for protecting a semiconductor wafer, separators (not shown) may be provided on the surface side of the adhesive layer. The separator is an element for protecting the pressure-sensitive adhesive layer from exposure, and is separated from the pressure-sensitive adhesive tape when the pressure-sensitive adhesive tape for protecting a semiconductor wafer of the present invention is used. Examples of the separator include plastic films and papers surface-coated with a polyethylene terephthalate (PET) film, a polyethylene film, a polypropylene film, and a release agent such as a fluorine-based release agent or a long chain alkyl acrylate release agent.

[Method of Manufacturing Semiconductor Device]
A semiconductor device can be manufactured using the adhesive tape for semiconductor wafer protection of the present invention. Specifically, in the step of affixing the semiconductor wafer to the adhesive layer side in the adhesive tape for protecting a semiconductor wafer of the present invention (sometimes referred to as “process A”) and the adhesive tape for protecting a semiconductor wafer of the present invention With the semiconductor wafer held, the semiconductor device can be manufactured by a manufacturing method including a step of thinning the semiconductor wafer by grinding (sometimes referred to as “step B”).

In the method of manufacturing the semiconductor device, as one embodiment (the first embodiment), as shown in FIGS. 3A and 3B, after the step A, a step of forming the modified region 30a on the semiconductor wafer (Modified region forming step) may be included. The semiconductor wafer W has a first surface Wa and a second surface Wb. Various semiconductor elements (not shown) are already formed on the first surface Wa side of the semiconductor wafer W, and wiring structures (not shown) necessary for the semiconductor elements are already formed on the first surface Wa. It is done. Then, in the modified region forming step, after bonding the adhesive tape X1 for protecting a semiconductor wafer of the present invention having the adhesive surface X1a in step A to the first surface Wa side of the semiconductor wafer W, the adhesive for protecting the semiconductor wafer In a state where the semiconductor wafer W is held by the tape X1, the laser beam whose focusing point is aligned inside the wafer is taken along the planned dividing line with respect to the semiconductor wafer W from the side opposite to the adhesive tape X1 for protecting the semiconductor wafer. Then, the modified region 30a is formed in the semiconductor wafer W due to the ablation by multiphoton absorption. The modified region 30a is a weakened region for separating the semiconductor wafer W into semiconductor chip units. The method of forming the modified region 30a on the planned dividing line by laser beam irradiation in the semiconductor wafer is described in detail in, for example, JP-A-2002-192370, but the laser beam irradiation condition in the embodiment is, for example, It adjusts suitably within the range of the following conditions. Note that the modified region forming step may be performed before the step A.
<Laser light irradiation conditions>
(A) Laser light Laser light source Semiconductor laser pumped Nd: YAG laser Wavelength 1064 nm
Laser beam spot cross section 3.14 × 10 ^-8 cm ²
Oscillation mode Q switch pulse Repetition frequency 100kHz or less Pulse width 1μs or less Output 1mJ or less Laser light quality TEM00
Polarization characteristics Linearly polarized (B) focusing lens Magnification: up to 100 times NA 0.55
Transmittance 100% or less for laser light wavelength (C) Movement speed of the processing table on which the semiconductor substrate is mounted 280 mm / s or less

  In step B, as shown in FIG. 3C, in a state where the semiconductor wafer W is held by the adhesive tape X1 for protecting a semiconductor wafer, grinding processing from the second surface Wb is performed until the semiconductor wafer W reaches a predetermined thickness. The semiconductor wafer 30A that can be singulated into a plurality of semiconductor chips 31 is formed. Grinding can be performed using a grinding apparatus equipped with a grinding wheel.

  The singulated semiconductor wafer 30A obtained in step B is subjected to the subsequent step (dicing step or the like). For example, the separable semiconductor wafer 30A obtained in step B is attached to the die bond film side of the dicing die bond film, and the adhesive tape X1 for semiconductor wafer protection is peeled off from the semiconductor wafer 30A. When the pressure-sensitive adhesive tape X1 for protecting a semiconductor wafer is peeled off, an adhesive strength reduction treatment (radiation irradiation, thermal expansion and the like) may be appropriately performed. Then, under relatively low temperature conditions, the dicing tape in the dicing die bond film is expanded to cut the semiconductor wafer 30A at the modified region 30a, and the die bond film is also cut accordingly to obtain a semiconductor chip with a die bond film. .

  In the method of manufacturing a semiconductor device, as another embodiment (second embodiment), the dividing groove forming step shown in FIG. 4 may be performed before the step A, instead of the modified region forming step. In the dividing groove forming step shown in FIG. 4, first, the dividing groove 30b is formed in the semiconductor wafer W as shown in FIGS. 4 (a) and 4 (b). The semiconductor wafer W has a first surface Wa and a second surface Wb. Various semiconductor elements (not shown) are already formed on the first surface Wa side of the semiconductor wafer W, and wiring structures (not shown) necessary for the semiconductor elements are already formed on the first surface Wa. It is done. Then, after bonding the wafer processing tape T having the adhesive surface Ta to the second surface Wb side of the semiconductor wafer W, the first processing of the semiconductor wafer W is performed with the semiconductor wafer W held by the wafer processing tape T. A dividing groove 30b of a predetermined depth is formed on the surface Wa side using a rotating blade such as a dicing apparatus. The dividing groove 30b is an air gap for separating the semiconductor wafer W into semiconductor chip units (in FIG. 4, the dividing groove 30b is schematically represented by a thick line).

  Then, in step A, as shown in FIG. 4C, bonding of the adhesive tape X2 for semiconductor wafer protection having the adhesive surface X2a to the first surface Wa side of the semiconductor wafer W, and from the semiconductor wafer W The wafer processing tape T is peeled off.

  Next, in step B, as shown in FIG. 4D, with the semiconductor wafer W held by the adhesive tape X2 for protecting a semiconductor wafer, the semiconductor wafer W is extended from the second surface Wb to a predetermined thickness. Thin by grinding process. Thus, the semiconductor wafer 30B that can be singulated into the plurality of semiconductor chips 31 is formed. Specifically, the semiconductor wafer 30B has a portion (connection portion) in which the portion to be singulated into the plurality of semiconductor chips 31 in the wafer is connected on the second surface Wb side.

  The individualizable semiconductor wafer 30B obtained in step B is then subjected to a dicing step or the like as in the first embodiment, and the adhesive tape X2 for protecting a semiconductor wafer is peeled off at that time.

  In the above-described method of manufacturing a semiconductor device, as still another embodiment (third embodiment), step B shown in FIG. 5 may be performed instead of step B described above with reference to FIG. . After passing through the process described above with reference to FIG. 4C, in step B shown in FIG. 5, with the semiconductor wafer W held by the adhesive tape X2 for protecting a semiconductor wafer, the wafer reaches a predetermined thickness. The semiconductor wafer division body 30C including the plurality of semiconductor chips 31 and held by the adhesive tape X2 for semiconductor wafer protection is formed by thinning by grinding from the second surface Wb. In the step B, a method (first method) of grinding the wafer may be adopted until the dividing groove 30b is exposed to the second surface Wb side, or the method before the dividing groove 30b is reached from the second surface Wb side A method of grinding the wafer up to the end and thereafter forming a crack between the dividing groove 30b and the second surface Wb by the action of the pressing force from the rotary grinding wheel to the wafer to form the semiconductor wafer divided body 30C (second method ) May be adopted. Depending on the method adopted, the depth from the first surface Wa of the dividing groove 30b formed as described above with reference to FIGS. 4A and 4B is appropriately determined. In FIG. 5, the dividing grooves 30 b having undergone the first method, or the dividing grooves 30 b having undergone the second method and the cracks connected to the dividing grooves 30 b are schematically represented by thick lines. Then, in the present embodiment, the semiconductor wafer divided body 30C thus manufactured as the semiconductor wafer divided body is used instead of the semiconductor wafer 30A, and thereafter subjected to a dicing process or the like as in the first embodiment. At that time, the adhesive tape X2 for semiconductor wafer protection is peeled off.

  EXAMPLES The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Example 1
100 parts by mass of an acrylic polymer composed of ethyl acrylate (EA) / butyl acrylate (BA) / acrylic acid (AA) = 50/50/5 (mass ratio), polyisocyanate compound (trade name "CORONATE L" A pressure-sensitive adhesive composition containing 1 part by mass of Tosoh Corp., 3 parts by mass of a photopolymerization initiator (trade name "IRGACURE 651", manufactured by BASF Corp.), and toluene was prepared. The pressure-sensitive adhesive composition is applied to a 50 μm-thick PET film (trade name “Lumirror S105, manufactured by Toray Industries, Inc.), and the solvent is removed by heating at 120 ° C. for 120 seconds to form a 45 μm-thick pressure-sensitive adhesive layer A1. It formed.
Subsequently, the surface which gave a silicone treatment of 38-micrometer-thick polyester-type separator (brand name "MRF", Mitsubishi resin Co., Ltd. make) was bonded on the said adhesive layer A1 surface, and adhesive tape A was obtained.

  100 parts by mass of acrylic polymer composed of 2-ethylhexyl acrylate (2-EHA) / acryloyl morpholine / hydroxyethyl acrylate (HEA) = 75/25/10 (mass ratio), polyisocyanate compound A pressure-sensitive adhesive composition was prepared, including 5 parts by mass of "Colonate L" manufactured by Tosoh Corp., 3 parts by mass of a photopolymerization initiator (trade name "IRGACURE 651" manufactured by BASF, Inc.), and toluene. The pressure-sensitive adhesive composition is applied to the surface of a 38 μm-thick polyester separator (trade name “Diafoil MRF”, manufactured by Mitsubishi Resins Co., Ltd.) subjected to silicone treatment, and then heated at 120 ° C. for 120 seconds for desolvation Then, a pressure-sensitive adhesive layer A2 having a thickness of 5 μm was formed.

  Then, the separator is peeled off from the pressure-sensitive adhesive tape A, and the above-mentioned pressure-sensitive adhesive layer A2 is adhered onto the pressure-sensitive adhesive layer A1 of the pressure-sensitive adhesive tape A, transferred, and stored at 50 ° C. for 72 hours [PET film (50 μm) / adhesiveness The adhesive tape of Example 1 which has the structure of agent layer A1 (45 micrometers) / adhesive layer A2 (5 micrometers) was obtained.

Example 2
100 parts by mass of acrylic polymer composed of 2-ethylhexyl acrylate (2-EHA) / methyl acrylate (MA) / acrylic acid (AA) = 30/70/10 (mass ratio), polyisocyanate compound (trade name) An adhesive composition comprising 1 part by mass of “Coronato L”, manufactured by Tosoh Corp., 3 parts by mass of a photopolymerization initiator (trade name “IRGACURE 651”, manufactured by BASF Corp.), and ethyl acetate was prepared. The pressure-sensitive adhesive composition is applied to a 50 μm-thick PET film (trade name “Lumirror S105, manufactured by Toray Industries, Inc.), and the solvent is removed by heating at 120 ° C. for 120 seconds to form a 45 μm-thick pressure-sensitive adhesive layer B1. It formed.
Subsequently, the surface which gave a silicone treatment of 38-micrometer-thick polyester-type separator (brand name "MRF", Mitsubishi resin Co., Ltd. make) was bonded on the said adhesive layer B1 surface, and the adhesive tape B was obtained.

  100 parts by mass of acrylic polymer composed of 2-ethylhexyl acrylate (2-EHA) / acryloyl morpholine / hydroxyethyl acrylate (HEA) = 75/25/10 (mass ratio), polyisocyanate compound A pressure-sensitive adhesive composition was prepared, containing 1 part by mass of the name “Coronato L”, manufactured by Tosoh Corp., 3 parts by mass of a photopolymerization initiator (trade name “IRGACURE 651”, manufactured by BASF Corp.), and toluene. The pressure-sensitive adhesive composition is applied to the silicone-treated surface of a 38 μm-thick polyester-based separator (trade name “MRF”, manufactured by Mitsubishi Resins Co., Ltd.), and the solvent is removed by heating at 120 ° C. for 120 seconds. A 5 μm thick pressure-sensitive adhesive layer B2 was formed.

  Then, the separator is peeled off from the adhesive tape B, and the above-mentioned adhesive layer B2 is adhered and transferred onto the adhesive layer B1 of the adhesive tape B, and stored for 72 hours at 50 ° C. [PET film (50 μm) / adhesive] The adhesive tape of Example 2 which has the structure of agent layer B1 (45 micrometers) / adhesive layer B2 (5 micrometers) was obtained.

Example 3
A pressure-sensitive adhesive tape C having a pressure-sensitive adhesive layer C1 is produced in the same manner as the pressure-sensitive adhesive tape B except that the thickness of the pressure-sensitive adhesive layer is 25 μm, and the separator is peeled off from the pressure-sensitive adhesive tape C. Then, the pressure-sensitive adhesive layer A2 prepared in Example 1 is attached and transferred, and stored at 50 ° C. for 72 hours, [PET film (50 μm) / pressure-sensitive adhesive layer C1 (25 μm) / pressure-sensitive adhesive layer A2 (5 μm) ] The adhesive tape of Example 3 which has a structure of] was obtained.

Example 4
A pressure-sensitive adhesive tape D having a pressure-sensitive adhesive layer D1 is prepared in the same manner as the pressure-sensitive adhesive tape A except that the thickness of the pressure-sensitive adhesive layer is 25 μm, and the separator is peeled from the pressure-sensitive adhesive tape D. The pressure-sensitive adhesive layer B2 prepared in Example 2 is attached and transferred, stored at 50 ° C. for 72 hours, and having a configuration of [PET film (50 μm) / adhesive layer D1 / adhesive layer B2]. The adhesive tape of Example 4 was obtained.

Example 5
100 parts by mass of an acrylic polymer composed of ethyl acrylate (EA) / butyl acrylate (BA) / acrylic acid (AA) = 50/50/5 (mass ratio), polyisocyanate compound (trade name "CORONATE L" , Tosoh Corp. 1 part by mass, and a pressure-sensitive adhesive composition containing toluene were prepared. The pressure-sensitive adhesive composition is applied to a 50 μm-thick PET film (trade name “Lumirror S105, manufactured by Toray Industries, Inc.), and the solvent is removed by heating at 120 ° C. for 120 seconds to form a 50 μm-thick pressure-sensitive adhesive layer E1. It formed.
Then, a silicone-treated surface of a 38 μm thick polyester-based separator (trade name “MRF”, manufactured by Mitsubishi Resins Co., Ltd.) is attached to the surface of the pressure-sensitive adhesive layer E1 and stored for 72 hours at 50 ° C. The adhesive tape of Example 5 which has the structure of PET film (50 micrometers) / adhesive layer E1 (50 micrometers) was obtained.

Example 6
100 parts by mass of acrylic polymer composed of 2-ethylhexyl acrylate (2-EHA) / methyl acrylate (MA) / acrylic acid (AA) = 30/70/10 (mass ratio), polyisocyanate compound (trade name) A pressure-sensitive adhesive composition containing 1 part by mass of “Coronato L” (manufactured by Tosoh Corporation) and ethyl acetate was prepared. The pressure-sensitive adhesive composition is applied to a 50 μm-thick PET film (trade name “Lumirror S105, manufactured by Toray Industries, Inc.), and the solvent is removed by heating at 120 ° C. for 120 seconds to form a 25 μm-thick pressure-sensitive adhesive layer F1. It formed.
Subsequently, the surface which gave a silicone treatment of 38-micrometer-thick polyester-type separator (brand name "MRF", Mitsubishi resin Co., Ltd. make) was bonded on the said adhesive layer F1 surface, and the adhesive tape F was obtained.

  100 parts by mass of acrylic polymer composed of 2-ethylhexyl acrylate (2-EHA) / acryloyl morpholine / hydroxyethyl acrylate (HEA) = 75/25/10 (mass ratio), polyisocyanate compound A pressure-sensitive adhesive composition was prepared, including 3 parts by weight of "Colonate L" (manufactured by Tosoh Corp.), 3 parts by weight of a photopolymerization initiator (trade name "IRGACURE 2959", manufactured by BASF Corp.), and toluene. The pressure-sensitive adhesive composition is applied to the silicone-treated surface of a 38 μm-thick polyester-based separator (trade name “MRF”, manufactured by Mitsubishi Resins Co., Ltd.), and the solvent is removed by heating at 120 ° C. for 120 seconds. A pressure-sensitive adhesive layer F2 having a thickness of 5 μm was formed.

  Then, the separator is peeled off from the pressure-sensitive adhesive tape F, the above-mentioned pressure-sensitive adhesive layer F2 is stuck on the pressure-sensitive adhesive layer F1 of the pressure-sensitive adhesive tape F, transferred, and stored at 50 ° C. for 72 hours [PET film (50 μm) / adhesiveness The adhesive tape of Example 6 which has the structure of agent layer F1 (25 micrometers) / adhesive layer F2 (5 micrometers) was obtained.

Comparative Example 1
100 parts by mass of acrylic polymer composed of ethyl acrylate (EA) / butyl acrylate (BA) / hydroxyethyl acrylate (HEA) = 50/50/5 (mass ratio), polyisocyanate compound (trade name: "Corronate" L ", Tosoh Corp. make) 0.2 mass part, a photoinitiator (brand name" IRGACURE 651 ", BASF Corporation make) 3 mass parts, and the adhesive composition containing toluene were prepared. The pressure-sensitive adhesive composition is applied to a 50 μm-thick PET film (trade name “Lumirror S105, manufactured by Toray Industries, Inc.), and the solvent is removed by heating at 120 ° C. for 120 seconds to form a 30 μm-thick pressure-sensitive adhesive layer G1. It formed.
Next, a silicone-treated surface of a 38 μm thick polyester-based separator (trade name “MRF”, manufactured by Mitsubishi Resins Co., Ltd.) is attached to the surface of the pressure-sensitive adhesive layer G1, and stored at 50 ° C. for 72 hours. The adhesive tape of the comparative example 1 which has the structure of PET film (50 micrometers) / adhesive layer G1 (30 micrometers) was obtained.

Comparative example 2
A pressure-sensitive adhesive tape of Comparative Example 2 having a configuration of [PET film (50 μm) / pressure-sensitive adhesive layer H1 (50 μm)] was obtained in the same manner as Comparative Example 1 except that the thickness of the pressure-sensitive adhesive layer was 50 μm.

<Evaluation>
The following evaluation was performed about each adhesive layer and each adhesive tape which were obtained by the Example and the comparative example. The results are shown in Table 1.

(Maximum increase rate)
A thermomechanical analyzer (trade name "Q-400", TA Instruments Inc.) is cut out from each adhesive tape obtained in each of the example and the comparative example into a strip of 10 mm in width and 10 mm in length with a cutter knife. The test piece is heated from −70 ° C. to 150 ° C. while applying a load of 0.11 N in the thickness direction to the entire test piece by the compression and expansion method under the following measurement conditions. The displacement of the thickness of the test piece was measured continuously. The state of the change of the expansion rate (increasing rate) in the thickness direction of a test piece in 23-100 degreeC in that case is shown to FIGS. 6 to 13, the horizontal axis represents temperature (° C.), and the vertical axis represents expansion rate (%) with respect to the thickness at 23 ° C. Then, the thickness of the strip-shaped test piece at 23 ° C. was A, and the maximum thickness of the strip-shaped test piece at 23 to 100 ° C. was B, and the maximum increase rate was determined by the following equation. The results are shown in the "maximum increase rate" column of Table 1.
Maximum increase rate (%) = (B-A) / A x 100
<Measurement conditions>
Measurement mode: Compression and expansion method Measurement load: 110 mN
Probe diameter: 6 mmφ
Temperature program: -70 ° C to 150 ° C
Heating rate: 5 ° C / min
Measurement atmosphere: N ₂ (flow rate 200 ml / min)

(Loss factor by nano indentation method)
Each pressure-sensitive adhesive layer obtained in each of the example and the comparative example was cut into about 1 cm square and fixed to a predetermined support to be a measurement sample, and a nano indenter (trade name "TriboIndenter", manufactured by Hysitron Inc.) The nanoindentation measurement was performed under the following conditions. Then, the obtained loss factor (tan δ) is shown in the column of “loss factor” in Table 1.
Working indenter: Berkovich (triangular pyramid)
Measurement method: Dynamic measurement Measurement temperature: 25 ° C (room temperature)
Frequency: 100Hz
Amplitude: 2 nm

(Crack resistance)
Using a product name “ML300-Integration” (manufactured by Tokyo Seimitsu Co., Ltd.) as a laser processing apparatus, the focusing point is aligned inside a 12-inch semiconductor wafer (silicon mirror wafer) to form a grid (8 mm × 12 mm) Laser light was irradiated from the surface along the planned dividing line to form a modified region inside the semiconductor wafer. The irradiation of the laser light was performed under the following conditions.
(A) Laser light
Laser light source Semiconductor laser pumped Nd: YAG laser
Wavelength 1064 nm
Laser beam spot cross section 3.14 × 10 ^-8 cm ²
Oscillation form Q switch pulse
Repetition frequency 100kHz
Pulse width 30ns
Output 20μJ / pulse
Laser light quality TEM00 40
Polarization characteristic Linearly polarized light (B) Focusing lens
50 times magnification
NA 0.55
60% transmittance to laser light wavelength
(C) Movement speed of the processing table on which the semiconductor substrate is mounted 100 mm / sec

After forming the modified region inside the semiconductor wafer, the adhesive tapes obtained in the examples and comparative examples are attached to the surface of the semiconductor wafer, and a back grinder (trade name "DGP 8760", manufactured by Disco Corporation) is used. The back surface was ground so that the thickness of the semiconductor wafer was 25 μm, and the semiconductor wafer was cut accordingly. And it observed with the optical microscope (50 times of magnification) about the cutting part of 500 semiconductor chips divided into pieces. Count the number of defects due to crack generation that could be confirmed by optical microscope observation, calculate [number of defects / 500] as a defect rate, and the case where the above defect rate is 1% or less is ○, the above defect rate is 1% The case of exceeding was evaluated as x. The evaluation results are shown in the column of "crack resistance" in Table 1.

1, 2, X 1, X 2 Adhesive tape for semiconductor wafer protection 11, 21 Base material 12, 22a, 22b, 22 Adhesive layer W, 30A, 30B Semiconductor wafer 30C Semiconductor wafer division 30a Modification area 30b Division groove 31 Semiconductor chip

Claims (2)

What is claimed is: 1. A pressure-sensitive adhesive tape for semiconductor wafer protection, comprising: a base material; and a pressure-sensitive adhesive layer laminated on the base material,
The thickness of the substrate at 23 ° C. is 10 to 150 μm,
23 to a thickness of the pressure-sensitive adhesive tape at 23 ° C. when the pressure-sensitive adhesive tape is heated from −70 ° C. to 150 ° C. in a state of applying a load of 0.11 N in the thickness direction by the compression expansion method of the thermomechanical analyzer. The adhesive tape for semiconductor wafer protection whose maximum increase rate of the thickness of the said adhesive tape in 100 degreeC is 1.2% or less.   The semiconductor wafer protection according to claim 1, comprising at least one pressure-sensitive adhesive layer having a loss coefficient (tan δ) by the nano-indentation method at a temperature of 25 ° C and a frequency of 100 Hz as 1.0 as the pressure-sensitive adhesive layer. Adhesive tape.

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