Adhesive tape for semiconductor processing

Abstract

The present invention addresses the problem of providing an adhesive tape for semiconductor processing that has excellent cutability by blade. According to the present invention, an adhesive tape for semiconductor processing includes a layered structure that is formed by layering, in order, a buffer layer, a substrate, and an adhesive layer, the buffer layer satisfying both condition (α) and condition (β). - Condition (α): the breaking energy of the buffer layer at 23°C is at least 15 MJ / m3. - Condition (β): When the buffer layer is tension tested at 23°C, the slope Δρ80–100 of the increase in stress as the strain (ε80) at 80% of the breaking strain (ε100) increases to the breaking strain (ε100) is at least 30 MPa.

Description

[Technical Field]

[0001] The present invention relates to an adhesive tape for semiconductor processing. More specifically, the present invention relates to an adhesive tape for semiconductor processing, a method for using the adhesive tape for semiconductor processing, and a method for manufacturing a semiconductor device using the adhesive tape for semiconductor processing. [Background technology]

[0002] In recent years, with the rapid progress in miniaturization and multi-functionality of various electronic devices, there has been a demand for smaller and thinner semiconductor chips to be installed in these devices. Thinning of semiconductor chips is generally achieved by grinding the back surface of the semiconductor wafer. Another known method for obtaining thin semiconductor chips is called Dicing Before Grinding (DBG). DBG is a method in which grooves of a predetermined depth are formed from the front side (circuit formation side) of the semiconductor wafer using a dicing blade or the like, and then the back surface of the semiconductor wafer is ground, and the semiconductor wafer is divided into individual pieces by grinding to obtain semiconductor chips. DBG allows for simultaneous back-side grinding and individual fraction of semiconductor wafers, enabling the efficient manufacturing of thin semiconductor chips.

[0003] Furthermore, as a variation of DBG, a method has been proposed in which a modified region is formed inside the semiconductor wafer using a laser or plasma, without forming grooves on the surface side of the semiconductor wafer, and the semiconductor wafer is fragmented into individual pieces by the stress during backside grinding of the semiconductor wafer to obtain semiconductor chips. In this method, the semiconductor wafer is cut in the crystal direction starting from the modified region. Therefore, the occurrence of chipping can be reduced compared to DBG using a dicing blade. As a result, semiconductor chips with excellent flexural strength can be obtained, and further thinning of semiconductor chips becomes possible. In addition, compared to DBG in which grooves of a predetermined depth are formed on the surface of the semiconductor wafer using a dicing blade, there is no region in the semiconductor wafer that is removed by the dicing blade (in other words, the kerf width is minimal), which has the advantage of superior semiconductor chip yield.

[0004] Incidentally, when manufacturing semiconductor chips that include a back grinding process of semiconductor wafers, such as DBG or a modified DBG method, it is common practice to attach a semiconductor processing adhesive tape called a back grind sheet to the surface of the semiconductor wafer in order to protect the circuits on the surface of the semiconductor wafer and to hold the semiconductor wafer and semiconductor chip in place. As such adhesive tapes for semiconductor processing, for example, an adhesive tape for semiconductor processing having a laminated structure in which a buffer layer, a substrate, and an adhesive layer are laminated in that order has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-183008 [Overview of the project] [Problems that the invention aims to solve]

[0006] Incidentally, when manufacturing a semiconductor chip including a back grinding process of a semiconductor wafer such as DBG or a modified method of DBG, when the semiconductor wafer is back ground by a grinder or the like, if there is an extra adhesive tape for semiconductor processing on the outer periphery of the semiconductor wafer, the grinder may bite into the extra adhesive tape for semiconductor processing. Therefore, the adhesive tape for semiconductor processing is cut along the outer periphery of the semiconductor wafer before back grinding.

[0007] However, with the miniaturization and thinning of semiconductor chips, chipping or breakage of semiconductor chips (hereinafter referred to as "cracks in semiconductor chips") may occur due to cut dust generated during the cutting of the adhesive tape for semiconductor processing. Therefore, the inventors of the present invention studied the main factors causing the generation of cut dust in order to suppress the occurrence of cracks in semiconductor chips. As a result, it was found that when the adhesive tape for semiconductor processing is cut with a blade, the buffer layer is rubbed due to the contact between the blade and the buffer layer, and the resin constituting the buffer layer is twisted or the like, causing the cut surface to become rough, thereby generating cut dust.

[0008] Based on such findings, the inventors of the present invention considered that as a method for suppressing the generation of cut dust, it is effective to improve the cutting property of the adhesive tape for semiconductor processing by a blade and suppress the roughness of the cut surface of the buffer layer, and further conducted intensive studies to arrive at the present invention.

[0009] Therefore, an object of the present invention is to provide an adhesive tape for semiconductor processing having excellent cutting property by a blade.

Means for Solving the Problems

[0010] As a result of intensive studies, the inventors of the present invention have found that an adhesive tape for semiconductor processing having a buffer layer satisfying specific requirements can solve the above problems, and have completed the present invention.

[0011] That is, the present invention relates to the following [1] to [7]. [1] It has a laminated structure in which a buffer layer, a base material, and an adhesive layer are laminated in this order, A semiconductor processing adhesive tape wherein the buffer layer satisfies both of the following requirements (α) and (β). • Requirement (α): The rupture energy of the buffer layer at 23°C is 15 MJ / m 3 That's all. • Requirement (β): When the buffer layer is subjected to a tensile test at a temperature of 23°C, the fracture strain (ε 100 ) 80% strain (ε 80 ) is the fracture strain (ε 100 The stress increase gradient Δρ until it increases to ). 80-100 However, it is over 30 MPa. [2] The semiconductor processing adhesive tape according to [1] above, wherein the substrate satisfies the following requirement (γ). • Requirement (γ): Fracture strain (ε) at a temperature of 23°C 100 ) and fracture stress (ρ) at a temperature of 23°C 100 The product of ) is 60 MPa or more. [3] The semiconductor processing adhesive tape according to [1] or [2] above, wherein the thickness of the adhesive layer is less than 100 μm. [4] A method of using the semiconductor processing adhesive tape described in any of [1] to [3] above, A method of use for performing backside grinding of a semiconductor wafer, comprising attaching the semiconductor processing adhesive tape to the surface of the semiconductor wafer and cutting the semiconductor processing adhesive tape along the outer circumference of the semiconductor wafer. [5] A method for manufacturing a semiconductor device, comprising the step (S1) of attaching a semiconductor processing adhesive tape described in any of [1] to [3] above to the surface of a semiconductor wafer and cutting the semiconductor processing adhesive tape along the outer circumference of the semiconductor wafer. [6] In the method for manufacturing a semiconductor device described in [5] above, Furthermore, a method for manufacturing a semiconductor device, including the following step (S2). • Process (S2): A process of grinding the semiconductor wafer from the back side. [7] In the method for manufacturing a semiconductor device described in [6] above, Furthermore, a method for manufacturing a semiconductor device, including the following step (S3). • Process (S3): Process of dicing the semiconductor wafer to form individual pieces. [8] In the method for manufacturing a semiconductor device described in [6] above, As the semiconductor wafer, a semiconductor wafer having grooves formed on its surface is used. A manufacturing method comprising the above step (S2), wherein the semiconductor wafer is divided into a plurality of chips starting from the grooves. [9] In the method for manufacturing a semiconductor device described in [6] above, As the semiconductor wafer, a semiconductor wafer in which a modified region is formed internally is used, or a modified region is formed internally of the semiconductor wafer after the above step (S1). A manufacturing method comprising the above step (S2), wherein the semiconductor wafer is divided into a plurality of chips starting from the modified region. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an adhesive tape for semiconductor processing that has excellent cutting properties with a blade. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic cross-sectional view showing an example of the adhesive tape for semiconductor processing of the present invention. [Figure 2] This is a schematic diagram of the process for manufacturing the semiconductor device of the present invention. [Figure 3] This figure shows the analysis model using Abaqus. [Figure 4] These are Abaqus analysis images of Example 1 sim. and Comparative Example 3 sim. in "Evaluation of cutting performance by blade (1): Evaluation by simulation". [Figure 5] These are the scanning electron microscope (SEM) observation results (photographs used as substitutes for drawings) of the cross-sections of Example 1 exp. and Comparative Example 3 exp. in "Evaluation of cutting performance by blade (2): Experimental evaluation". [Modes for carrying out the invention]

[0014] The upper and lower limit values of the numerical ranges described in this specification can be arbitrarily combined. For example, when the numerical ranges "A to B" and "C to D" are described, the numerical ranges "A to D" and "C to B" are also included in the scope of the present invention. The numerical range "lower limit value to upper limit value" described in this specification means, unless otherwise specified, that it is not less than the lower limit value and not more than the upper limit value. In this specification, the numerical values of the examples are numerical values that can be used as the upper limit value or the lower limit value.

[0015] In this specification, "(meth)acrylate" is a concept that includes both "acrylate" and "methacrylate", and the same applies to other similar terms. For example, "(meth)acryloyl group" is a concept that includes both "acryloyl group" and "methacryloyl group". In this specification, the weight average molecular weight and the number average molecular weight are polystyrene conversion values measured by gel permeation chromatography (GPC) method.

[0016] [Aspects of Adhesive Tapes for Semiconductor Processing] The adhesive tape for semiconductor processing of the present invention has a laminated structure in which a buffer layer, a base material, and an adhesive layer are laminated in this order. And the buffer layer satisfies both the following requirement (α) and the following requirement (β). · Requirement (α): The breaking energy of the buffer layer at 23°C is 15 MJ / m 3 or more. · Requirement (β): When the buffer layer is subjected to a tensile test at a temperature of 23°C, the stress increase gradient Δρ 100 until the strain (ε 80 ) at 80% of the breaking strain (ε 100 ) increases to the breaking strain (ε 80-100 ) is 30 MPa or more.

[0017] FIG. 1 shows a cross-sectional schematic view of one aspect of the adhesive tape for semiconductor processing of the present invention. The adhesive tape 1 for semiconductor processing shown in FIG. 1 has a laminated structure in which a buffer layer 11, a base material 12, and an adhesive layer 13 are laminated in this order. The semiconductor processing adhesive tape 1 shown in Figure 1 has a buffer layer 11, a substrate 12, and an adhesive layer 13 directly laminated together without any other layers in between. Therefore, the semiconductor processing adhesive tape 1 shown in Figure 1 consists only of the buffer layer 11, the substrate 12, and the adhesive layer 13.

[0018] However, the semiconductor processing adhesive tape 1 is not necessarily limited to this form. For example, other layers may be provided as needed between the buffer layer 11 and the substrate 12, or between the substrate 12 and the adhesive layer 13. Examples of such other layers include a primer layer and a layer for embedding bumps formed on the circuit surface of the wafer. Furthermore, a release sheet may be laminated on the surface of the adhesive layer 13 to protect it until use. In addition, a coating layer may be provided on the surface of the buffer layer 11. In Figure 1, the buffer layer 11, the base material 12, and the adhesive layer 13 are shown as single-layer structures, but they may also be multi-layer structures.

[0019] The physical properties and composition of each component of adhesive tape for semiconductor processing will be described in detail below. In the following explanation, "adhesive tape for semiconductor processing" may be abbreviated as simply "adhesive tape."

[0020] [Buffer layer] The buffer layer has the function of easing stress during back-side grinding of the semiconductor wafer, preventing cracks and chips from occurring in the semiconductor wafer. Furthermore, when adhesive tape is attached to the semiconductor wafer, and after the tape is cut along the outer circumference of the wafer, the semiconductor wafer is placed on a chuck table via the adhesive tape and back-side grinding is performed. The presence of a buffer layer in the adhesive tape makes it easier to properly hold the semiconductor wafer on the chuck table. Thus, when performing back-side grinding of semiconductor wafers, the presence of a buffer layer in the adhesive tape offers significant advantages. However, because the buffer layer is softer than the base material, it also has drawbacks. Specifically, when the adhesive tape is cut, the resin in the buffer layer may twist or twist, resulting in a rough cut surface and the generation of cut dust.

[0021] The inventors, after careful consideration to overcome the above drawbacks, concluded that improving the cutting performance of the adhesive tape with a blade and suppressing roughness of the cut surface of the buffer layer would be effective in suppressing cut dust, and diligently conducted research. As a result, they found that by focusing on the fracture energy of the buffer layer and the increasing stress gradient near the fracture point in the stress-strain diagram of the buffer layer, the cutting performance of the buffer layer with a blade could be improved. Further research led to the identification of the above requirements (α) and (β).

[0022] <Requirements (α)> Requirement (α) specifies that the rupture energy of the buffer layer at 23°C is 15 MJ / m². 3 The above is specified. The rupture energy of the buffer layer at 23°C is 15 MJ / m 3 As described above, and with the buffer layer also satisfying requirement (β), the cutting performance of the buffer layer by a blade can be improved. The breaking energy of the buffer layer at 23°C is 15 MJ / m 3 Based on the above, it is presumed that the buffer layer will be less prone to deformation even when struck by a blade, twisting of the buffer layer will be suppressed, and cutting performance will be improved. The rupture energy of the buffer layer at 23°C is 15 MJ / m². 3 If it is less than this, the cutting performance of the blade in the buffer layer cannot be made excellent. Here, from the viewpoint of making it easier to improve the cutting performance of the buffer layer by the blade, the breaking energy of the buffer layer at 23°C is preferably 17 MJ / m 3 More preferably 22 MJ / m 3 More preferably 27 MJ / m 3 That's all. Furthermore, from the viewpoint of preventing blade wear, the breaking energy of the buffer layer at 23°C is preferably 150 MJ / m 3 The following applies: The fracture energy of the buffer layer at 23°C is the integral value obtained up to the fracture point in the stress-strain diagram, which is a linear representation of stress and strain, obtained from a tensile test at 23°C based on JIS K7161:1994 and JIS K7127:1999. The strain can be determined by the initial specimen length (mm) × elongation (%). The fracture stress and fracture strain described later are the stress and strain at the time of fracture (fracture point) in the above tensile test, respectively.

[0023] <Requirements (β)> Requirement (β) states that when the buffer layer is subjected to a tensile test at a temperature of 23°C, the fracture strain (ε 100 ) 80% strain (ε 80 ) is the fracture strain (ε 100 The stress increase gradient Δρ until it increases to ). 80-100 However, it is specified that the pressure must be 30 MPa or higher. Stress increase gradient Δρ 80-100 However, at pressures of 30 MPa or higher, work hardening (strain hardening) improves the degree of hardening of the buffer layer during the cutting process, suppressing deformation (elongation) of the buffer layer during cutting. Therefore, it is presumed that twisting of the buffer layer is suppressed, resulting in improved cutting performance. Furthermore, the stress gradient Δρ in the buffer layer increases. 80-100 However, if the pressure is less than 30 MPa, the cutting performance of the buffer layer by the blade cannot be made excellent. Here, from the viewpoint of improving the cutting performance of the buffer layer by the blade, the stress increase gradient Δρ 80-100 The stress gradient Δρ is preferably 50 MPa or higher, more preferably 70 MPa or higher, even more preferably 75 MPa or higher, even more preferably 80 MPa or higher, even more preferably 85 MPa or higher, even more preferably 90 MPa or higher, even more preferably 95 MPa or higher, and even more preferably 100 MPa or higher. 80-100 It is usually below 200 MPa.

[0024] <Other physical properties> The buffer layer is a softer layer compared to the substrate. This appropriately relieves stress during back-side grinding of the semiconductor wafer. Furthermore, from the viewpoint of more appropriately mitigating stress during backside grinding of semiconductor wafers, the elastic modulus of the buffer layer at 23°C is preferably 1,200 MPa or less, more preferably 1,000 MPa or less, even more preferably 800 MPa or less, even more preferably 700 MPa or less, and still most preferably 500 MPa or less.

[0025] Furthermore, the increase gradient Δρ of the fracture energy and stress mentioned above. 80-100 From the viewpoint of making it easier to obtain, the rupture stress of the buffer layer is preferably 30 MPa or more, more preferably 50 MPa or more, even more preferably 55 MPa or more, and even more preferably 60 MPa or more. Furthermore, the stress increase gradient Δρ 80-100 From the perspective of making it easier to obtain, the fracture strain of the buffer layer (ε 100 The ratio is preferably 0.50 or higher, more preferably 1.0 or higher, even more preferably 1.1 or higher, even more preferably 1.2 or higher, even more preferably 1.3 or higher, and even more preferably 1.4 or higher.

[0026] <Thickness of the buffer layer> The thickness of the buffer layer is preferably 1 μm to 100 μm, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 60 μm, from the viewpoint of appropriately relieving stress during backside grinding of the semiconductor wafer.

[0027] <Buffer layer composition> The buffer layer has the function of appropriately relieving stress during back grinding of the semiconductor wafer and can be used without particular limitations as long as it satisfies the above requirements (α) and (β). However, from the viewpoint of making it easier to exhibit the effects of the present invention, the buffer layer is preferably a cured product of a buffer layer forming composition containing an energy ray polymerizable compound. The following describes, in order, each component contained in the layer formed from the buffer layer-forming composition containing an energy ray polymerizable compound.

[0028] <<Layer formed from a buffer layer-forming composition containing an energy-ray polymerizable compound>> A buffer layer-forming composition containing an energy-ray polymerizable compound hardens when irradiated with energy rays. In this specification, "energy beam" means an electromagnetic wave or charged particle beam that has an energy quantum. Examples of energy beams include ultraviolet rays, radiation, and electron beams. Ultraviolet rays can be irradiated, for example, by using high-pressure mercury lamps, fusion lamps, xenon lamps, black lights, or LED lamps as ultraviolet light sources. Electron beams can be irradiated using those generated by electron accelerators, etc. The buffer layer forming composition containing an energy-ray polymerizable compound more preferably contains urethane (meth)acrylate (a1). By containing the above-mentioned (a1) component, the buffer layer forming composition makes it easier to adjust the rupture energy of the buffer layer to the above-mentioned range. Furthermore, it is more preferable that the buffer layer forming composition contains, in addition to (a1) above, one or more polymerizable compounds selected from (a2) having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms and (a3) ​​having a functional group. Furthermore, the buffer layer-forming composition may also contain a polyfunctional polymerizable compound (a4) in addition to the above components (a1) to (a3). Furthermore, the buffer layer forming composition preferably contains a photopolymerization initiator, and may also contain other additives and resin components to the extent that it does not impair the effects of the present invention. The following describes in detail each component contained in the buffer layer-forming composition containing energy ray polymerizable compounds.

[0029] (Urethane (meth)acrylate (a1)) Urethane (meth)acrylate (a1) is a compound having at least a (meth)acryloyl group and a urethane bond, and possesses the property of polymerization curing by energy ray irradiation. Urethane (meth)acrylate (a1) is an oligomer or a polymer, and in this embodiment, an oligomer is preferred. In the following explanation, "urethane (meth)acrylate (a1)" will also be referred to as "component (a1)".

[0030] The weight-average molecular weight (Mw) of component (a1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, and even more preferably 2,000 to less than 10,000. Furthermore, the number of (meth)acryloyl groups in component (a1) (hereinafter also referred to as "number of functional groups") may be monofunctional, difunctional, or trifunctional or more, but monofunctional or difunctional is preferred. Component (a1) can be obtained, for example, by reacting a terminal isocyanate urethane prepolymer, which is obtained by reacting a polyol compound with a polyvalent isocyanate compound, with a (meth)acrylate having a hydroxyl group. Component (a1) may be used alone or in combination of two or more types.

[0031] The polyol compound used as a raw material for component (a1) is not particularly limited as long as it is a compound having two or more hydroxyl groups. Specific examples of polyol compounds include alkylenediols, polyether-type polyols, polyester-type polyols, and polycarbonate-type polyols. Among these, polyester-type polyols or polycarbonate-type polyols are preferred. The polyol compound may be a bifunctional diol, a trifunctional triol, or a polyol with four or more functions, but a bifunctional diol is preferred, and a polyester-type diol or a polycarbonate-type diol is more preferred.

[0032] Examples of polyvalent isocyanate compounds include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and ω,ω'-diisocyanate dimethylcyclohexane; and aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, and naphthalene-1,5-diisocyanate. Among these, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferred.

[0033] A urethane (meth)acrylate (a1) can be obtained by reacting the above-mentioned polyol compound with a polyvalent isocyanate compound to obtain a terminal isocyanate urethane prepolymer, and then reacting the (meth)acrylate having a hydroxyl group with the (meth)acrylate having a hydroxyl group. The (meth)acrylate having a hydroxyl group is not particularly limited as long as it is a compound having at least one molecule containing both a hydroxyl group and a (meth)acryloyl group.

[0034] Specific examples of (meth)acrylates having a hydroxyl group include, for example, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate; hydroxyl group-containing (meth)acrylamides such as N-methylol (meth)acrylamide; and reaction products obtained by reacting vinyl alcohol, vinyl phenol, and diglycidyl esters of bisphenol A with (meth)acrylic acid. Among these, hydroxyalkyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.

[0035] The conditions for reacting the terminal isocyanate urethane prepolymer and the (meth)acrylate having a hydroxyl group are preferably such that the reaction is carried out at 60°C to 100°C for 1 to 4 hours in the presence of a solvent and catalyst, which may be added as needed. The content of component (a1) in the buffer layer forming composition is preferably 10% to 80% by mass, more preferably 30% to 80% by mass, and even more preferably 40% to 80% by mass, based on the total amount (100% by mass) of the buffer layer forming composition.

[0036] (a2) Polymerizable compounds having alicyclic or heterocyclic groups with 6 to 20 ring-forming atoms A polymerizable compound (a2) (hereinafter also referred to as "component (a2)") having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms is a polymerizable compound having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms, and more preferably a compound having at least one (meth)acryloyl group, and more preferably a compound having one (meth)acryloyl group. By using component (a2), the film-forming properties of the resulting buffer layer-forming composition can be improved.

[0037] Although there is some overlap between the definition of component (a2) and the definition of component (a3) ​​described later, the overlapping portion is included in component (a3). For example, a compound having at least one (meth)acryloyl group, an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms, and a functional group such as a hydroxyl group, epoxy group, amide group, or amino group is included in the definitions of both component (a2) and component (a3), but in this invention, such a compound is included in component (a3).

[0038] The number of ring-forming atoms in the alicyclic or heterocyclic group of component (a2) is preferably 6 to 20, more preferably 6 to 18, and even more preferably 6 to 16. Examples of atoms that form the ring structure of the heterocyclic group include carbon atoms, nitrogen atoms, oxygen atoms, sulfur atoms, and the like. The number of ring-forming atoms refers to the number of atoms that make up the ring itself in a compound with a ring-shaped structure. Atoms that do not form a ring (for example, hydrogen atoms bonded to ring-forming atoms) and atoms included in substituents when the ring is substituted by substituents are not included in the number of ring-forming atoms.

[0039] Specific components (a2) include, for example, alicyclic group-containing (meth)acrylates such as isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, and adamantane (meth)acrylate; heterocyclic group-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and morpholine (meth)acrylate; and the like. Furthermore, component (a2) may be used alone or in combination of two or more types. Among alicyclic group-containing (meth)acrylates, isobornyl (meth)acrylate is preferred, and among heterocyclic group-containing (meth)acrylates, tetrahydrofurfuryl (meth)acrylate is preferred.

[0040] When the buffer layer forming composition contains component (a2), the content of component (a2) in the buffer layer forming composition is preferably 10% to 80% by mass, more preferably 20% to 70% by mass, based on the total amount (100% by mass) of the buffer layer forming composition.

[0041] (Polymerizable compound having a functional group (a3)) The polymerizable compound (a3) ​​having a functional group (hereinafter also referred to as "component (a3)") is a polymerizable compound containing a functional group such as a hydroxyl group, epoxy group, amide group, or amino group, and more preferably a compound having at least one (meth)acryloyl group, and more preferably a compound having one (meth)acryloyl group. Component (a3) ​​has good compatibility with component (a1), making it easier to adjust the viscosity of the buffer layer forming composition to an appropriate range. Furthermore, it becomes easier to adjust the rupture energy of the buffer layer formed from the composition to the above range, resulting in good buffering performance even when the buffer layer is relatively thin. Examples of component (a3) ​​include hydroxyl group-containing (meth)acrylates, epoxy group-containing compounds, amide group-containing compounds, and amino group-containing (meth)acrylates.

[0042] Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenylhydroxypropyl (meth)acrylate, cyclohexanol (meth)acrylate, 4-tert-butylcyclohexanol acrylate, and 2-hydroxy-3-phenoxypropyl acrylate. Examples of epoxy group-containing compounds include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and allyl glycidyl ether. Among these, epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate are preferred. Examples of amide group-containing compounds include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide. Examples of amino group-containing (meth)acrylates include primary amino group-containing (meth)acrylates, secondary amino group-containing (meth)acrylates, and tertiary amino group-containing (meth)acrylates.

[0043] Among these, hydroxyl group-containing (meth)acrylates are preferred, hydroxyl group-containing (meth)acrylates having an aromatic ring such as phenylhydroxypropyl (meth)acrylate, hydroxyl group-containing (meth)acrylates having an alicyclic ring such as cyclohexanol (meth)acrylate and 4-tert-butylcyclohexanol acrylate are more preferred, and hydroxyl group-containing (meth)acrylates having an alicyclic ring are even more preferred. The number of ring-forming carbon atoms in the alicyclic ring is preferably 6 to 20, more preferably 6 to 18, and even more preferably 6 to 16. Furthermore, component (a3) ​​may be used alone or in combination of two or more types.

[0044] When the buffer layer forming composition contains component (a3), the content of component (a3) ​​in the buffer layer forming composition is preferably 5% to 50% by mass, more preferably 10% to 40% by mass, and even more preferably 20% to 30% by mass, based on the total amount (100% by mass) of the buffer layer forming composition, from the viewpoint of making it easier to adjust the rupture energy of the buffer layer to the above range and from the viewpoint of making it easier to improve the film-forming properties of the buffer layer forming composition. Furthermore, when the buffer layer forming composition contains both components (a2) and (a3), the content ratio of component (a2) to component (a3) ​​in the buffer layer forming composition [(a2) / (a3)] is preferably 0.5 to 3.0, more preferably 1.0 to 3.0, even more preferably 1.3 to 3.0, and even more preferably 1.5 to 2.8 by mass. Furthermore, from the viewpoint of facilitating the preparation of a buffer layer that satisfies the above requirements (α) and (β), the buffer layer forming composition preferably contains component (a3), and component (a3) ​​is preferably a hydroxyl group-containing (meth)acrylate having an alicyclic ring.

[0045] (Polyfunctional polymerizable compound (a4)) A polyfunctional polymerizable compound (a4) (hereinafter also referred to as "component (a4)") is a compound having two or more photopolymerizable unsaturated groups. Photopolymerizable unsaturated groups are functional groups containing a carbon-carbon double bond, such as (meth)acryloyl groups, vinyl groups, allyl groups, and vinylbenzyl groups. Two or more types of photopolymerizable unsaturated groups may be combined. A three-dimensional network structure (crosslinked structure) is formed by the reaction of the photopolymerizable unsaturated groups in the polyfunctional polymerizable compound with the (meth)acryloyl groups in component (a1), or by the reaction of the photopolymerizable unsaturated groups in component (a4) with each other. When a polyfunctional polymerizable compound is used, the number of crosslinked structures formed by energy ray irradiation increases compared to when a compound containing only one photopolymerizable unsaturated group is used, so the buffer layer exhibits unique viscoelasticity, making it easier to adjust the fracture energy within the above range.

[0046] Note that there is some overlap between the definition of component (a4) and the definitions of components (a2) and (a3) ​​mentioned above, but the overlapping parts are included in component (a4). For example, a compound having an alicyclic or heterocyclic group with 6 to 20 ring-forming atoms and having two or more (meth)acryloyl groups is included in the definitions of both component (a4) and component (a2), but in this invention, such a compound is included in component (a4). Also, a compound containing a functional group such as a hydroxyl group, epoxy group, amide group, or amino group and having two or more (meth)acryloyl groups is included in the definitions of both component (a4) and component (a3), but in this invention, such a compound is included in component (a4).

[0047] From the above viewpoint, the number of photopolymerizable unsaturated groups (number of functional groups) in a polyfunctional polymerizable compound is preferably 2 to 10, and more preferably 3 to 6.

[0048] Furthermore, the weight-average molecular weight of component (a4) is preferably 30 to 40,000, more preferably 100 to 10,000, and even more preferably 200 to 1,000.

[0049] Specific components (a4) include, for example, diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, divinylbenzene, vinyl (meth)acrylate, divinyl adipate, N,N'-methylenebis(meth)acrylamide, etc. Among these, dipentaerythritol hexa(meth)acrylate is preferred. Furthermore, component (a4) may be used alone or in combination of two or more types.

[0050] The content of component (a4) in the buffer layer forming composition is preferably 0% to 40% by mass, more preferably 0% to 20% by mass, and even more preferably 0% to 15% by mass, based on the total amount (100% by mass) of the buffer layer forming composition.

[0051] (Polymerizable compounds other than components (a1) to (a4) (a5)) The buffer layer forming composition may also contain polymerizable compound (a5) (hereinafter also referred to as "component (a5)") as other components in addition to the above components (a1) to (a4), to the extent that it does not impair the effects of the present invention. Examples of component (a5) include alkyl (meth)acrylates having an alkyl group with 1 to 20 carbon atoms; vinyl compounds such as styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam. Furthermore, component (a5) may be used alone or in combination of two or more types.

[0052] The content of component (a5) in the buffer layer forming composition is preferably 0% to 20% by mass, more preferably 0% to 10% by mass, even more preferably 0% to 5% by mass, and even more preferably 0% to 2% by mass.

[0053] (Photopolymerization initiator) The buffer layer forming composition preferably contains a photopolymerization initiator, from the viewpoint of shortening the polymerization time by light irradiation and reducing the amount of light irradiation when forming the buffer layer.

[0054] Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. More specifically, examples include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. These photopolymerization initiators may be used individually or in combination of two or more.

[0055] The amount of photopolymerization initiator in the buffer layer-forming composition is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the total amount of energy ray polymerizable compounds.

[0056] (Other additives) The buffer layer forming composition may contain other additives, to the extent that they do not impair the effects of the present invention. Examples of other additives include one or more selected from antistatic agents, antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, etc. When these additives are included, the content of each additive in the buffer layer forming composition is preferably 0.01 to 6 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the total amount of energy ray polymerizable compounds.

[0057] (Resin components) The buffer layer-forming composition may contain a resin component, to the extent that it does not impair the effects of the present invention. Examples of resin components include polyene-thiol resins, polyolefin resins such as polybutene, polybutadiene, and polymethylpentene, and thermoplastic resins such as styrene copolymers. The content of these resin components in the buffer layer forming composition is preferably 0% to 20% by mass, more preferably 0% to 10% by mass, even more preferably 0% to 5% by mass, and even more preferably 0% to 2% by mass.

[0058] The buffer layer formed from a buffer layer-forming composition containing an energy-ray polymerizable compound is obtained by polymerizing and curing the buffer layer-forming composition of the above composition by energy-ray irradiation. In other words, the buffer layer is a cured product of the buffer layer-forming composition. Therefore, the buffer layer contains polymerization units derived from component (a1). Preferably, the buffer layer also contains at least one of polymerization units derived from component (a2) and polymerization units derived from component (a3). Furthermore, it may also contain at least one of polymerization units derived from component (a4) and polymerization units derived from component (a5). The proportion of each polymerization unit in the buffer layer usually corresponds to the ratio (compounding ratio) of each component constituting the buffer layer forming composition. For example, if the content of component (a1) in the buffer layer forming composition is 10% to 70% by mass relative to the total amount (100% by mass) of the buffer layer forming composition, the buffer layer will contain 10% to 70% by mass of polymerization units derived from component (a1). Similarly, if the content of component (a2) in the buffer layer forming composition is 10% to 80% by mass relative to the total amount (100% by mass) of the buffer layer forming composition, the buffer layer will contain 10% to 80% by mass of polymerization units derived from component (a2). The same applies to components (a3) ​​to (a5).

[0059] The rupture energy of the buffer layer at 23°C can be controlled, for example, by adjusting the weight-average molecular weight of the urethane (meth)acrylate (a1) and the thickness of the buffer layer, and by appropriately selecting monomer species, when the buffer layer is a cured product of a buffer layer forming composition containing an energy-ray polymerizable compound.

[0060] [Base material] The base material functions as a support for the adhesive tape. Various resin films can be used as substrates. Specifically, these include polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins such as polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymer, and norbornene resin; ethylene copolymers such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, and ethylene-(meth)acrylic acid ester copolymer; polyvinyl chloride such as polyvinyl chloride and vinyl chloride copolymer; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and fully aromatic polyester; and resin films consisting of one or more selected from polyurethane, polyimide, polyamide, polycarbonate, fluororesin, polyacetal, modified polyphenylene oxide, polyphenylene sulfide, polysulfone, polyetherketone, and acrylic polymers. Modified films such as crosslinked films and ionomer films are also used. The substrate may be a single-layer resin film made of one or more resins selected from these resins, or it may be a laminated film made by laminating two or more of these resin films.

[0061] Furthermore, since the base material is harder than the buffer layer, roughness of the cut surface is less likely to occur when cutting with a blade compared to the buffer layer. However, from the viewpoint of providing a base material with superior cutting performance, it is preferable that the base material satisfies the following requirement (γ). • Requirement (γ): Fracture strain (ε) at a temperature of 23°C 100 ) and fracture stress (ρ) at a temperature of 23°C 100The product of ) is 60 MPa or more.

[0062] Furthermore, the base material has an elastic modulus at 23°C that is preferably 200 MPa or higher, more preferably 500 MPa or higher, and even more preferably 1,000 MPa or higher. It is also preferably 30,000 MPa or lower, more preferably 10,000 MPa or lower, and even more preferably 6,000 MPa or lower.

[0063] The thickness of the substrate is not particularly limited, but is preferably 110 μm or less, more preferably 15 μm to 110 μm, and even more preferably 20 μm to 105 μm. By making the substrate thickness 110 μm or less, it becomes easier to control the peeling force of the adhesive tape. Also, by making the substrate thickness 15 μm or more, the substrate can more easily function as a support for the adhesive tape.

[0064] Furthermore, the substrate may contain plasticizers, lubricants, infrared absorbers, ultraviolet absorbers, fillers, colorants, antistatic agents, antioxidants, catalysts, etc., to the extent that they do not impair the effects of the present invention. The substrate may also be transparent or opaque, and may be colored or vapor-deposited as desired. Furthermore, at least one surface of the substrate may be subjected to an adhesive treatment such as corona treatment to improve adhesion with at least one of the buffer layer and the adhesive layer. The substrate may also consist of the resin film described above and an easy-adhesion layer coated on at least one surface of the resin film.

[0065] The composition for forming an easily adhesive layer is not particularly limited, but examples include compositions containing polyester resins, urethane resins, polyester-urethane resins, acrylic resins, etc. The composition for forming an easily adhesive layer may optionally contain crosslinking agents, photopolymerization initiators, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, etc. The thickness of the easy-adhesion layer is preferably 0.01 μm to 10 μm, more preferably 0.03 μm to 5 μm. In this embodiment, the thickness of the easy-adhesion layer is small compared to the thickness of the substrate, so the thickness of the resin film with the easy-adhesion layer is substantially the same as the thickness of the substrate. Furthermore, because the material of the easy-adhesion layer is soft, it has little effect on the elastic modulus, and the elastic modulus of the substrate is substantially the same as the Young's modulus of the resin film, even when the easy-adhesion layer is present.

[0066] For example, the fracture strain (ε) at a temperature of 23°C, as defined by requirement (γ). 100 ) and fracture stress (ρ) at a temperature of 23°C 100 The product of ( ) and the elastic modulus of the substrate can be controlled by selecting the resin composition, adding plasticizers, and stretching conditions during resin film manufacturing. Specifically, when polyethylene terephthalate film is used as the substrate, the elastic modulus of the substrate tends to decrease as the proportion of ethylene in the copolymer components increases. Also, the elastic modulus of the substrate tends to decrease as the amount of plasticizer added to the resin composition constituting the substrate increases.

[0067] [Adhesive layer] The adhesive layer is not particularly limited as long as it has adequate pressure-sensitive adhesion at room temperature, but it is preferable that its shear storage modulus at 23°C is 0.05 MPa to 0.50 MPa. The surface of a semiconductor wafer is usually uneven, with circuits and other structures formed on it. When the shear storage modulus of the adhesive layer is within the above range, it becomes possible to ensure sufficient contact between the uneven wafer surface and the adhesive layer when applying adhesive tape to the uneven wafer surface, and to properly exhibit the adhesive properties of the adhesive layer. Therefore, it becomes possible to reliably fix the adhesive tape to the semiconductor wafer and to properly protect the wafer surface during backside grinding. From these viewpoints, it is more preferable that the shear storage modulus of the adhesive layer is 0.12 to 0.35 MPa. Note that, if the adhesive layer is formed from an energy-ray curable adhesive, the shear storage modulus of the adhesive layer refers to the shear storage modulus before curing by energy-ray irradiation.

[0068] The shear storage modulus can be measured by the following method. A sample is prepared by punching out a circle with a diameter of 7.9 mm from an adhesive layer with a thickness of approximately 0.5 to 1 mm. The elastic modulus of the sample is measured using a Rheometric ARES dynamic viscoelasticity analyzer at a frequency of 1 Hz and a temperature range from -30°C to 150°C at a heating rate of 3°C / min. The elastic modulus at a measurement temperature of 23°C is taken as the shear storage modulus at 23°C.

[0069] The thickness of the adhesive layer is preferably less than 100 μm, more preferably 5 to 80 μm, and even more preferably 10 to 70 μm. Making the adhesive layer this thin suppresses the generation of cut dust when the adhesive tape is cut, and makes it easier to prevent cracks in the semiconductor chip that occur during backside grinding.

[0070] The adhesive layer is formed from, for example, an acrylic adhesive, a urethane adhesive, a rubber adhesive, a silicone adhesive, etc., but an acrylic adhesive is preferred. Furthermore, it is preferable that the adhesive layer be formed from an energy-ray curable adhesive. By forming the adhesive layer from an energy-ray curable adhesive, it becomes possible to set the shear storage modulus at 23°C within the above range before curing by energy irradiation, and to easily set the peel force to 1000 mN / 50 mm or less after curing.

[0071] The following describes specific examples of adhesives, but these are non-limiting examples, and the adhesive layer in the present invention should not be interpreted as being limited to these examples. As an energy-ray curable adhesive, for example, an energy-ray curable adhesive composition containing an energy-ray curable compound other than an energy-ray curable resin (hereinafter also referred to as "Type X adhesive composition") in addition to a non-energy-ray curable adhesive resin (also referred to as "adhesive resin I") can be used. Furthermore, as an energy-ray curable adhesive, an adhesive composition containing an energy-ray curable adhesive resin (hereinafter also referred to as "adhesive resin II") in which an unsaturated group has been introduced into the side chain of a non-energy-ray curable adhesive resin as the main component, and not containing an energy-ray curable compound other than an energy-ray curable compound (hereinafter also referred to as "Type Y adhesive composition") may also be used.

[0072] Furthermore, as an energy-ray curable adhesive, a combination of type X and type Y, that is, an energy-ray curable adhesive composition (hereinafter also referred to as "XY-type adhesive composition") which includes an energy-ray curable adhesive resin II as well as an energy-ray curable compound other than the adhesive resin, may also be used. Among these, it is preferable to use an XY-type adhesive composition. By using an XY-type composition, it is possible to have sufficient adhesive properties before curing, while keeping the peeling force from the semiconductor wafer sufficiently low after curing.

[0073] However, the adhesive may be formed from a non-energy-ray curable adhesive composition that does not harden when irradiated with energy rays. The non-energy-ray curable adhesive composition contains at least a non-energy-ray curable adhesive resin I, but does not contain the above-mentioned energy-ray curable adhesive resin II or energy-ray curable compound.

[0074] In the following explanation, "adhesive resin" is used as a term referring to either or both of the above-mentioned adhesive resins I and II. Specific examples of adhesive resins include acrylic resins, urethane resins, rubber resins, and silicone resins, but acrylic resins are preferred. The following provides a more detailed explanation of acrylic adhesives that use acrylic resins as the adhesive resin.

[0075] <Acrylic resin> Acrylic polymer (b) is used in acrylic resins. Acrylic polymer (b) is obtained by polymerizing monomers containing at least alkyl (meth)acrylate, and contains constituent units derived from alkyl (meth)acrylate. Examples of alkyl (meth)acrylate include alkyl groups with 1 to 20 carbon atoms, and the alkyl group may be linear or branched. Specific examples of alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, etc. Alkyl (meth)acrylate may be used alone or in combination of two or more types.

[0076] Furthermore, the acrylic polymer (b) preferably contains constituent units derived from alkyl (meth)acrylate, in which the alkyl group has 4 or more carbon atoms, from the viewpoint of improving the adhesive strength of the adhesive layer. The number of carbon atoms of the alkyl (meth)acrylate is preferably 4 to 12, and more preferably 4 to 6. In addition, the alkyl (meth)acrylate, in which the alkyl group has 4 or more carbon atoms, is preferably an alkyl acrylate.

[0077] In the acrylic polymer (b), the alkyl (meth)acrylate having 4 or more carbon atoms in the alkyl group is preferably 40% to 98% by mass, more preferably 45% to 95% by mass, and even more preferably 50% to 90% by mass, relative to the total amount of monomers constituting the acrylic polymer (b) (hereinafter also simply referred to as "total amount of monomers").

[0078] The acrylic polymer (b) is preferably a copolymer that includes structural units derived from alkyl (meth)acrylate having 4 or more carbon atoms in the alkyl group, as well as structural units derived from alkyl (meth)acrylate having 1 to 3 carbon atoms in the alkyl group, in order to adjust the elastic modulus and adhesive properties of the adhesive layer. The alkyl (meth)acrylate is preferably an alkyl (meth)acrylate having 1 or 2 carbon atoms, more preferably methyl (meth)acrylate, and even more preferably methyl methacrylate. In the acrylic polymer (b), the alkyl (meth)acrylate having 1 to 3 carbon atoms in the alkyl group is preferably 1% to 30% by mass, more preferably 3% to 26% by mass, and even more preferably 6% to 22% by mass, based on the total amount of monomer.

[0079] The acrylic polymer (b) preferably has structural units derived from functional group-containing monomers in addition to the alkyl (meth)acrylate-derived structural units described above. Examples of functional groups in the functional group-containing monomers include hydroxyl groups, carboxyl groups, amino groups, epoxy groups, etc. The functional group-containing monomer can react with the crosslinking agent described later to become a crosslinking starting point, or react with the unsaturated group-containing compound to introduce unsaturated groups into the side chains of the acrylic polymer (b).

[0080] Examples of functional group-containing monomers include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers. These monomers may be used individually or in combination of two or more. Among these, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferred, and hydroxyl group-containing monomers are more preferred.

[0081] Examples of hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

[0082] Examples of monomers containing a carboxyl group include ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, and citraconic acid, and their anhydrides, as well as 2-carboxyethyl methacrylate.

[0083] The functional group-containing monomer is preferably 1% to 35% by mass, more preferably 3% to 32% by mass, and even more preferably 6% to 30% by mass, relative to the total amount of monomers constituting the acrylic polymer (b). Furthermore, the acrylic polymer (b) may also contain monomer-derived structural units that can copolymerize with the above-mentioned acrylic monomers, such as styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide.

[0084] The above acrylic polymer (b) can be used as a non-energy ray curable adhesive resin I (acrylic resin). An example of an energy ray curable acrylic resin is obtained by reacting the functional groups of the above acrylic polymer (b) with a compound having a photopolymerizable unsaturated group (also called an unsaturated group-containing compound).

[0085] The unsaturated group-containing compound is a compound having both a substituent that can be bonded to the functional group of the acrylic polymer (b) and a photopolymerizable unsaturated group. Examples of photopolymerizable unsaturated groups include (meth)acryloyl group, vinyl group, allyl group, vinylbenzyl group, etc., with (meth)acryloyl group being preferred. Furthermore, substituents that can be bonded to functional groups in unsaturated group-containing compounds include isocyanate groups and glycidyl groups. Therefore, examples of unsaturated group-containing compounds include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and glycidyl (meth)acrylate.

[0086] Furthermore, the unsaturated group-containing compound preferably reacts with some of the functional groups of the acrylic polymer (b). Specifically, it is preferable to react 50 to 98 mol% of the functional groups of the acrylic polymer (b) with the unsaturated group-containing compound, and more preferably 55 to 93 mol%. In this way, in the energy-ray curable acrylic resin, some of the functional groups remain without reacting with the unsaturated group-containing compound, making it easier to crosslink with a crosslinking agent. The weight-average molecular weight (Mw) of the acrylic resin is preferably 300,000 to 1,600,000, more preferably 400,000 to 1,400,000, and even more preferably 500,000 to 1,200,000.

[0087] <Energy-ray curable compounds> As the energy-curable compound contained in the X-type or XY-type adhesive composition, monomers or oligomers having an unsaturated group in the molecule and capable of polymerization curing by energy irradiation are preferred. Examples of such energy-ray curable compounds include polyvalent (meth)acrylate monomers such as trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol (meth)acrylate, as well as oligomers such as urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and epoxy (meth)acrylate.

[0088] Among these, urethane (meth)acrylate oligomers are preferred because they have a relatively high molecular weight and do not easily reduce the shear storage modulus of the adhesive layer. The molecular weight (weight-average molecular weight in the case of oligomers) of the energy ray-curable compound is preferably 100 to 12,000, more preferably 200 to 10,000, even more preferably 400 to 8,000, and even more preferably 600 to 6,000.

[0089] The content of the energy ray curable compound in the X-type adhesive composition is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and even more preferably 60 to 90 parts by mass, per 100 parts by mass of adhesive resin. On the other hand, the content of the energy-ray curable compound in the XY-type adhesive composition is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 3 to 15 parts by mass, per 100 parts by mass of the adhesive resin. In the XY-type adhesive composition, since the adhesive resin is energy-ray curable, it is possible to sufficiently reduce the peeling force after energy irradiation even with a small content of the energy-ray curable compound.

[0090] <Crosslinking agent> The adhesive composition preferably further contains a crosslinking agent. The crosslinking agent crosslinks the adhesive resins by reacting with, for example, functional groups derived from functional group-containing monomers of the adhesive resin. Examples of crosslinking agents include isocyanate-based crosslinking agents such as tolylene diisocyanate, hexamethylene diisocyanate, and their adducts; epoxy-based crosslinking agents such as ethylene glycol glycidyl ether; aziridine-based crosslinking agents such as hexa[1-(2-methyl)-aziridinyl]triphosphatriaidine; and chelate-based crosslinking agents such as aluminum chelate. These crosslinking agents may be used individually or in combination of two or more.

[0091] Among these, isocyanate-based crosslinking agents are preferred from the viewpoint of increasing cohesive force and improving adhesiveness, as well as from the viewpoint of ease of availability. From the viewpoint of promoting the crosslinking reaction, the amount of crosslinking agent added is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 4 parts by mass, per 100 parts by mass of adhesive resin.

[0092] <Photopolymerization initiator> Furthermore, if the adhesive composition is energy-ray curable, it is preferable that the adhesive composition further contains a photopolymerization initiator. By including a photopolymerization initiator, the curing reaction of the adhesive composition can proceed sufficiently even with relatively low-energy energy rays such as ultraviolet light.

[0093] Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. More specifically, examples include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloranthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0094] These photopolymerization initiators may be used individually or in combination of two or more. The amount of photopolymerization initiator added is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 5 parts by mass, per 100 parts by mass of adhesive resin.

[0095] <Other additives> The adhesive composition may contain other additives as long as they do not impair the effects of the present invention. Examples of other additives include antistatic agents, antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, and the like. When these additives are included, the amount of additive is preferably 0.01 to 6 parts by mass per 100 parts by mass of the adhesive resin.

[0096] Furthermore, the adhesive composition may be further diluted with an organic solvent to provide a solution, from the viewpoint of improving its applicability to substrates, buffer layers, and release sheets. Examples of organic solvents include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. These organic solvents may be the same organic solvents used during the synthesis of the adhesive resin, or one or more organic solvents other than those used during synthesis may be added to ensure uniform application of the adhesive composition solution.

[0097] [Release sheet] A release liner may be attached to the surface of the adhesive tape. Specifically, the release liner is attached to the surface of the adhesive layer of the adhesive tape. The release liner protects the adhesive layer during transport and storage. The release liner is attached to the adhesive tape in a removable manner and is peeled off and removed from the adhesive tape before the adhesive tape is used (i.e., before wafer attachment). The release sheet used is one in which at least one side has been treated to release the material. Specifically, this includes a release sheet in which a release agent is applied to the surface of a release sheet substrate.

[0098] A resin film is preferred as the substrate for the release sheet, and examples of resins constituting the resin film include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, and polyolefin resins such as polypropylene resin and polyethylene resin. Examples of release agents include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long-chain alkyl resins, alkyd resins, and fluorine resins. The thickness of the release sheet is not particularly limited, but is preferably 10 μm to 200 μm, and more preferably 20 μm to 150 μm.

[0099] [Method for manufacturing adhesive tape for semiconductor processing] There are no particular limitations on the method for manufacturing the semiconductor processing adhesive tape of the present invention, and it can be manufactured by known methods. For example, the method for manufacturing an adhesive tape having a laminated structure in which a buffer layer, a substrate, and an adhesive layer are stacked in this order is as follows.

[0100] When the buffer layer is formed from a buffer layer forming composition containing an energy ray polymerizable compound, the buffer layer is formed by coating and curing the buffer layer forming composition onto a release sheet, bonding the buffer layer to the substrate, and then removing the release sheet to obtain a laminate of the buffer layer and the substrate.

[0101] Then, the adhesive layer provided on the release sheet is bonded to the substrate side of the laminate, and an adhesive tape can be manufactured in which the release sheet is attached to the surface of the adhesive layer. The release sheet attached to the surface of the adhesive layer can be peeled off and removed as appropriate before use of the adhesive tape.

[0102] One method for forming a buffer layer on a release sheet is to directly apply a buffer layer-forming composition to the release sheet using a known coating method to form a coating film, and then irradiate this coating film with energy rays to form the buffer layer. Alternatively, the buffer layer may be formed by directly applying the buffer layer-forming composition to one side of a substrate and then heating and drying it or irradiating the coating film with energy rays.

[0103] Examples of methods for applying the buffer layer-forming composition include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating. Furthermore, to improve applicability, an organic solvent may be added to the buffer layer-forming composition, and the solution may be applied onto a release sheet.

[0104] When the buffer layer forming composition contains an energy ray polymerizable compound, it is preferable to form a buffer layer by curing the coated film of the buffer layer forming composition by irradiating it with energy rays. The curing of the buffer layer may be performed in a single curing treatment or in multiple stages. For example, the coated film on the release sheet may be completely cured to form a buffer layer before being bonded to the substrate, or the buffer layer forming film may be formed in a semi-cured state without completely curing the coated film, and after bonding the buffer layer forming film to the substrate, it may be irradiated with energy rays again to completely cure it and form a buffer layer. Ultraviolet light is preferred as the energy ray used in the curing treatment. When curing, the coated film of the buffer layer forming composition may be exposed, but it is preferable to cure it by irradiating it with energy rays while the coated film is covered with a release sheet or substrate and the coated film is not exposed.

[0105] One method for forming an adhesive layer on a release sheet is to directly apply an adhesive (adhesive composition) to the release sheet using a known application method, and then heat-dry the applied film to form the adhesive layer.

[0106] Alternatively, an adhesive layer may be formed by directly applying an adhesive (adhesive composition) to one side of the substrate. Examples of adhesive application methods include the spray coating method, bar coating method, knife coating method, roll coating method, blade coating method, die coating method, gravure coating method, etc., as described in the method for manufacturing the buffer layer.

[0107] [How to use adhesive tape for semiconductor processing] The semiconductor processing adhesive tape of the present invention is used by being attached to the surface (circuit formation surface) of a semiconductor wafer when performing backside grinding of the semiconductor wafer, and then cut along the outer circumference of the semiconductor wafer. In one embodiment of the present invention, the semiconductor processing adhesive tape of the present invention is used by being attached to the surface (circuit formation surface) of a semiconductor wafer when grinding the back surface of a semiconductor wafer (more specifically, when manufacturing a semiconductor chip that includes a back surface grinding process of a semiconductor wafer), and then cut along the outer circumference of the semiconductor wafer. Methods for manufacturing semiconductor chips that include a backside grinding process for semiconductor wafers include a method of dicing a semiconductor wafer after backside grinding to form individual pieces, and the DBG or DBG modification method described above. The semiconductor processing adhesive tape of the present invention exhibits excellent cutability with a blade. Therefore, when cutting the semiconductor processing adhesive tape along the outer circumference of a semiconductor wafer, less cut dust is generated, and the occurrence of chipping or damage to semiconductor chips caused by such cut dust is suppressed during the manufacturing of semiconductor chips, including the back surface grinding process of the semiconductor wafer.

[0108] Therefore, in one aspect of the present invention, the following methods of use are provided: (1) or (2). (1) A method of using the semiconductor processing adhesive tape of the present invention, wherein when grinding the back surface of a semiconductor wafer, the semiconductor processing adhesive tape is attached to the surface of the semiconductor wafer, and the semiconductor processing adhesive tape is cut along the outer circumference of the semiconductor wafer. (2) The method of use described in (1) above, wherein the semiconductor wafer used is a semiconductor wafer in which grooves are formed on the surface side or a semiconductor wafer in which a modified region is formed inside.

[0109] [Manufacturing method for semiconductor devices] The present invention relates to a method for manufacturing a semiconductor device, which includes a backside grinding step of a semiconductor wafer, and comprises the steps of attaching the semiconductor processing adhesive tape of the present invention to the surface (circuit formation surface) of a semiconductor wafer and cutting the semiconductor processing adhesive tape along the outer circumference of the semiconductor wafer (S1). The semiconductor processing adhesive tape of the present invention exhibits excellent cutability with a blade. Therefore, in the above process (S1), cut dust is less likely to be generated, and the occurrence of cracks in the semiconductor chip caused by such cut dust is suppressed.

[0110] Figure 2 shows a schematic diagram of the manufacturing process for the semiconductor device according to the present invention. The present invention provides a method for manufacturing a semiconductor device, broadly comprising the steps of: attaching a semiconductor processing adhesive tape to the surface (circuit formation surface) of a semiconductor wafer, cutting the semiconductor processing adhesive tape along the outer circumference of the semiconductor wafer (S1), and grinding the semiconductor wafer from the back side (S2). The semiconductor wafer may be diced into individual pieces after step (S2) (Embodiment 1). Furthermore, the semiconductor wafer may be pulverized in step (S2) (Embodiment 2). Specifically, as the semiconductor wafer, a semiconductor wafer having grooves formed on its surface may be used, and in process (S2), the semiconductor wafer may be divided into multiple chips starting from the grooves. Furthermore, as the semiconductor wafer, a semiconductor wafer with a modified region formed inside may be used, or a modified region may be formed inside the semiconductor wafer after step (S1), and in step (S2), the semiconductor wafer may be divided into multiple chips starting from the modified region.

[0111] The details of each step are described below.

[0112] <Process (S1)> In step (S1), the semiconductor processing adhesive tape of the present invention is attached to the surface (circuit formation surface) of a semiconductor wafer, and the semiconductor processing adhesive tape is cut along the outer circumference of the semiconductor wafer. The adhesive tape for semiconductor processing is applied to cover the surface (circuit formation surface) of the semiconductor wafer and the peripheral table extending around its periphery. The adhesive tape is then cut along the periphery of the semiconductor wafer by a blade such as a cutter, starting from the buffer layer side. The cutting speed is typically 10 to 300 mm / s. The blade temperature during cutting may be room temperature, or the blade may be heated before cutting.

[0113] Examples of semiconductor wafers used in this manufacturing method include silicon wafers, gallium arsenide wafers, silicon carbide wafers, lithium tantalate wafers, lithium niobate wafers, gallium nitride wafers, indium phosphate wafers, and glass wafers. The thickness of a semiconductor wafer before backside grinding is not particularly limited, but it is usually around 500 μm to 1000 μm. Furthermore, circuit formation on the surface of semiconductor wafers can be carried out by various methods, including conventionally used methods such as etching and lift-off methods.

[0114] When DBG is used in this manufacturing method, the semiconductor wafer to which the semiconductor processing adhesive tape is attached in step (S1) is a semiconductor wafer with grooves formed on its surface. Semiconductor wafers with grooves formed on their surface can be manufactured using conventionally known wafer dicing equipment, such as laser dicing or blade dicing. These grooves serve as the starting points for splitting the semiconductor wafer into individual semiconductor chips.

[0115] In this manufacturing method, when the DBG modification method is adopted, the semiconductor wafer to which the semiconductor processing adhesive tape is attached in step (S1) is a semiconductor wafer in which a modified region has been formed internally. However, this modified region may be formed after step (S1). The modified region is a brittle part of the semiconductor wafer and serves as the starting point for splitting the semiconductor wafer into individual semiconductor chips. Semiconductor wafers with modified regions formed inside are fabricated by irradiating the inside of the semiconductor wafer with a laser or plasma focused on that area. The laser or plasma irradiation may be performed from either the front or back side of the semiconductor wafer.

[0116] After process (S1) is completed, the semiconductor wafer with the semiconductor processing adhesive tape attached is placed on the chuck table and held in place by suction to the chuck table. At this time, the semiconductor wafer with the semiconductor processing adhesive tape attached is placed on the chuck table so that the chuck table and the buffer layer of the semiconductor processing adhesive tape are in direct contact. In other words, the semiconductor wafer is positioned with its surface facing the chuck table.

[0117] <Aspect 1> In embodiment 1, after performing step (S2), step (S3) is performed to separate the semiconductor wafer into individual pieces. In Embodiment 1, a semiconductor wafer without a division starting point is used, rather than a semiconductor wafer having a division starting point such as a semiconductor wafer with grooves formed on its surface or a semiconductor wafer with a modified region formed inside. (Process (S2)) In step (2), the back surface of the semiconductor wafer on the chuck table is ground. The thickness of the semiconductor wafer after backside grinding is not particularly limited, but is preferably about 5 μm to 100 μm, and more preferably 10 μm to 45 μm.

[0118] (Process (S3)) In step (S3), the semiconductor wafer that has undergone step (S2) is diced to form individual pieces. Dicing can be carried out using conventionally known methods such as blade dicing or laser dicing, as appropriate.

[0119] The shape of the individual semiconductor chips may be rectangular or elongated, such as a rectangle. The thickness of the individual semiconductor chips is not particularly limited, but is preferably about 5 μm to 100 μm, and more preferably 10 μm to 45 μm. The area of ​​the individual semiconductor chips is not particularly limited, but is preferably 600 mm². 2 Less than, more preferably 400 mm 2 Less than 300 mm, more preferably 300 mm 2 It is less than.

[0120] <Aspect 2> In embodiment 2, in step (S2), the semiconductor wafer is back-ground and the semiconductor wafer is divided into individual pieces. (Process (S2)) In step (S2), the back surface of the semiconductor wafer on the chuck table is ground to separate the semiconductor wafer into multiple semiconductor chips.

[0121] In the first embodiment of Embodiment 2, a semiconductor wafer with grooves formed on its surface is used. In this case, the back surface of the semiconductor wafer is ground down to at least the bottom of the grooves. This back surface grinding causes the grooves to become notches that penetrate the semiconductor wafer, and the semiconductor wafer is divided by these notches into individual semiconductor chips.

[0122] Furthermore, in the second embodiment of Embodiment 2, a semiconductor wafer with a modified region formed inside is used. Alternatively, the modified region may be formed inside the semiconductor wafer after step (S1). In the second embodiment of Embodiment 2, backside grinding may be performed up to the modified region, but it is not necessary to reach the modified region precisely. That is, backside grinding may be performed up to a position close to the modified region so that the semiconductor wafer is broken down into individual semiconductor chips starting from the modified region.

[0123] Alternatively, the obtained semiconductor chips may be fitted with a pickup tape (described later), and then the pickup tape may be stretched to widen the gaps between the chips.

[0124] Additionally, after the backside grinding is complete and prior to picking up the chip, dry polishing may be performed.

[0125] The shape, thickness, and area of ​​the individual semiconductor chips are as described in Embodiment 1. Furthermore, when using a semiconductor wafer with a modified region formed internally, it becomes easy to set the thickness of the individual semiconductor chips to 50 μm or less, more preferably 10 μm to 45 μm.

[0126] The semiconductor processing adhesive tape of the present invention exhibits excellent cutability with a blade. Therefore, in the above process (S1), cut dust is less likely to be generated. Consequently, even when manufacturing thin and miniaturized semiconductor chips in the process (S2) of Embodiment 1 and the process (S2) of Embodiment 2, the occurrence of chipping or damage to the semiconductor chip caused by the cut dust is suppressed.

[0127] <Removal of adhesive tape used in semiconductor processing> After step (S2), the semiconductor processing adhesive tape is peeled off the individual semiconductor wafers (i.e., multiple semiconductor chips). This process is carried out, for example, by the following method. If the adhesive layer of the adhesive tape for semiconductor processing is formed from an energy-ray curable adhesive, the adhesive layer is cured by irradiating it with energy rays. Next, a pickup tape is attached to the back side of the individual semiconductor wafers, and its position and orientation are aligned so that it can be picked up. At this time, a ring frame placed on the outer circumference of the wafer is also attached to the pickup tape, and the outer edge of the pickup tape is fixed to the ring frame. The wafer and ring frame may be attached to the pickup tape at the same time, or at different times. Next, the adhesive tape is peeled off from the multiple semiconductor chips held on the pickup tape.

[0128] Subsequently, multiple semiconductor chips on the pickup tape are picked up and fixed onto a substrate or the like to manufacture a semiconductor device. The pickup tape is not particularly limited, but for example, it is composed of an adhesive tape comprising a base material and an adhesive layer provided on at least one side of the base material.

[0129] Alternatively, adhesive tape can be used instead of pickup tape. Examples of adhesive tape include a laminate of a film-like adhesive and a release sheet, a laminate of dicing tape and a film-like adhesive, and a dicing-die bonding tape consisting of an adhesive layer and a release sheet that has the functions of both dicing tape and die bonding tape. In addition, a film-like adhesive may be bonded to the back side of the individual semiconductor wafers before applying the pickup tape. When using a film-like adhesive, the film-like adhesive may be the same shape as the wafer.

[0130] When using adhesive tape or when a film-like adhesive is applied to the back side of a semiconductor wafer that has been separated before applying the pickup tape, multiple semiconductor chips on the adhesive tape or pickup tape are picked up together with the adhesive layer, which is divided to match the shape of the semiconductor chips. The semiconductor chips are then fixed onto a substrate or the like via the adhesive layer, and a semiconductor device is manufactured. The division of the adhesive layer is performed by laser or expansion.

[0131] The semiconductor device manufacturing method of the present invention has been described above. The semiconductor processing adhesive tape of the present invention is particularly suitable for use in DBG deformation methods that yield a smaller calf width and thinner semiconductor chip group when semiconductor wafers are separated into individual pieces.

[0132] Furthermore, the semiconductor processing adhesive tape of the present invention can, of course, also be used to temporarily hold workpieces during processing of glass, ceramics, etc. It can also be used as various types of re-peelable adhesive tapes. [Examples]

[0133] The present invention will be specifically described by the following examples, but the present invention is not limited to the following examples.

[0134] [Manufacturing examples A1 to A4, comparative manufacturing examples B1 to B3, reference examples C1 to C2] <Manufacturing Example A1: Formation of Buffer Layer A-1> A buffer layer composition was obtained by mixing 75 parts by mass of urethane acrylate oligomer (CN8888, manufactured by Arkema Corporation) and 25 parts by mass of 4-tert-butylcyclohexanol acrylate, totaling 100 parts by mass, with 2.0 parts by mass of a photopolymerization initiator (BASF's "Irgacure 1173," 2-hydroxy-2-methyl-1-phenylpropan-1-one). The obtained buffer layer composition was coated onto a substrate PET film (Toyobo Co., Ltd.'s "Cosmoshine A4300", a double-sided easy-adhesion PET film, thickness: 50 μm) using a knife-coating method to form a buffer layer composition layer with a thickness of 28 μm. Immediately after coating, the buffer layer composition layer was irradiated with a high-pressure mercury lamp at an illuminance of 160 mW / cm². 2 , irradiation amount 500mJ / cm 2 By irradiating with ultraviolet light under these conditions, the buffer layer composition layer was cured, forming a 28 μm thick buffer layer A-1 on one side of the PET film substrate, thereby producing a PET substrate with buffer layer A-1.

[0135] <Manufacturing Example A2: Formation of buffer layer A-2> The composition of the buffer layer was modified as follows, and a buffer layer A-2 with a thickness of 28 μm was formed on the PET film substrate in the same manner as in production example A1. • Urethane acrylate oligomer (CN8888, manufactured by Arkema Corporation): 50 parts by mass · 4-tert-butylcyclohexanol acrylate: 40 parts by mass • Dipentaerythritol hexaacrylate: 10 parts by mass • Photopolymerization initiator (BASF "Irgacure 1173"): 2.0 parts by mass

[0136] <Manufacturing Example A3: Formation of buffer layer A-3> The composition of the buffer layer was modified as follows, and a buffer layer A-3 with a thickness of 28 μm was formed on the PET film substrate in the same manner as in manufacturing example A1. • Urethane acrylate oligomer (CN8888, manufactured by Arkema Corporation): 50 parts by mass · 4-tert-butylcyclohexanol acrylate: 45 parts by mass • Dipentaerythritol hexaacrylate: 5 parts by mass • Photopolymerization initiator (BASF "Irgacure 1173"): 2.0 parts by mass

[0137] <Manufacturing Example A4: Formation of buffer layer A-4> The composition of the buffer layer was modified as follows, and a buffer layer A-4 with a thickness of 28 μm was formed on the PET film substrate in the same manner as in production example A1. • Urethane acrylate oligomer (CN8888, manufactured by Arkema Corporation): 50 parts by mass Isobornyl acrylate: 45 parts by mass • Dipentaerythritol hexaacrylate: 5 parts by mass • Photopolymerization initiator (BASF "Irgacure 1173"): 2.0 parts by mass

[0138] <Comparative Manufacturing Example B1: Formation of Buffer Layer B-1> The composition of the buffer layer was modified as follows, and a buffer layer B-1 with a thickness of 28 μm was formed on the PET film substrate in the same manner as in production example A1. • Urethane acrylate oligomer (CN8888, manufactured by Arkema Corporation): 50 parts by mass • 3,3,5-Trimethylcyclohexanol acrylate: 50 parts by mass • Photopolymerization initiator (BASF "Irgacure 1173"): 2.0 parts by mass

[0139] <Comparative manufacturing example B2: Formation of buffer layer B-2> The composition of the buffer layer was modified as follows, and a buffer layer B-2 with a thickness of 28 μm was formed on the PET film substrate in the same manner as in production example A1. • Urethane acrylate oligomer (CN8888, manufactured by Arkema Corporation): 50 parts by mass Isobornyl acrylate: 45 parts by mass Tricyclodecanedimethanol diacrylate: 5 parts by mass • Photopolymerization initiator (BASF "Irgacure 1173"): 2.0 parts by mass

[0140] <Comparative manufacturing example B3: Formation of buffer layer B-3> The composition of the buffer layer was modified as follows, and a buffer layer B-3 with a thickness of 28 μm was formed on the PET film substrate in the same manner as in production example A1. • Urethane acrylate oligomer (CN8888, manufactured by Arkema Corporation): 50 parts by mass • Cyclic trimethylolpropane formal acrylate: 50 parts by mass • Photopolymerization initiator (BASF "Irgacure 1173"): 2.0 parts by mass

[0141] <Reference example C1: Base material C-1> As base material C-1, a PET film (Toyobo Co., Ltd.'s "Cosmoshine A4300", a PET film with easy-adhesion layers on both sides, thickness: 50 μm) was prepared.

[0142] <Reference example C2: Base material C-2> A polyolefin (PO) film (low-density polyolefin film, thickness: 25μ) was prepared as the base material C-2.

[0143] [Measurement Methods and Evaluation Methods] <Measurement and calculation of various physical properties of the buffer layer and substrate> The elastic modulus, fracture energy, fracture stress, and fracture strain of the base material and buffer layer were measured using a precision universal testing machine (device name "Autograph AG-IS" manufactured by Shimadzu Corporation). Specifically, measurement samples measuring 1.5 mm in width, 150 mm in length, and 0.2 mm in thickness were prepared for buffer layers A-1 to A-4, buffer layers B-1 to B-3, and base materials C-1 to C-2. Measurements were then performed on these measurement samples under the following conditions: 100 mm between chucks (25 mm at each end of the longitudinal direction of the measurement sample fixed to the apparatus), tensile speed 200 mm / sec, 23°C, and 50% RH. Furthermore, from the stress-strain data obtained, the fracture strain (ε) was determined for buffer layers A-1 to A-4, buffer layers B-1 to B-3, and base materials C-1 to C-2. 100 ) 80% strain (ε 80 ) is fracture strain (ε 100 The stress increase gradient Δρ until it increases to ). 80-100 The fracture stress and fracture strain (ε) were calculated. 100 The product of ) was also calculated.

[0144] <Evaluation of cutting performance by blades (1): Evaluation by simulation> Using the general-purpose finite element analysis software "Abaqus," we simulated and evaluated the cross-sectional state of semiconductor processing adhesive tape when cut with a blade. The analysis model is shown in Figure 3. The semiconductor wafer was assumed to be rectangular, and an analytical model was assumed in which a semiconductor processing adhesive tape having a laminated structure in which a buffer layer and a substrate are laminated was stacked on the semiconductor wafer. In this analytical model, it was assumed that one end of the semiconductor processing adhesive tape was constrained to the semiconductor wafer, and the other end was completely constrained to the outer periphery table. The angle between the buffer layer surface and the cutting edge of the blade was set to 57.2°, and the state of the cross-section of the semiconductor processing adhesive tape was analyzed when the blade was moved in a straight line along the semiconductor wafer at a cutting speed of 80 mm / s. In the above analysis model, the cutting edge properties were assumed to be rigid. Furthermore, regarding the blade, we assumed the use of an art knife (OLFA, model number "XB10"), and modeled only the part of the art knife involved in cutting, inputting its dimensions. The buffer layer and substrate were analyzed using the following combinations. • Example 1: Buffer layer A-1 / PET • Example 2: Buffer layer A-2 / PET • Example 3: Buffer layer A-3 / PET • Example 4: Buffer layer A-4 / PET Comparative example 1sim.: Buffer layer B-1 / PET Comparative example 2sim.: Buffer layer B-2 / PET Comparative example 3sim.: Buffer layer B-3 / PET ·Reference example 1sim.:PET ·Reference example 2sim.:PO The thickness of the buffer layer was set to 28 μm. The thickness of the substrate was set to 50 μm. Furthermore, the physical properties of the buffer layer and substrate were input as stress-strain data measured by the above-mentioned precision universal testing machine, along with the elastic modulus, yield stress, and fracture point based on that data. The coefficient of friction between the blade and the buffer layer was set to 0.25.

[0145] The evaluation criteria were as follows, with a score of 3 or higher considered a passing grade. 1: The sheet cross-section is very rough. 2: The sheet cross-section is rough. 3: The sheet cross-section is slightly rough. 4: There is only slight roughness visible on the sheet cross-section. 5: No roughness is observed in the sheet cross-section.

[0146] <Evaluation of cutting performance by blades (2): Experimental evaluation> We prepared an adhesive tape for semiconductor processing with the following configuration. • Example 1 exp.: Interceptor layer A-1 / PET / Adhesive layer Comparative example 3exp.: Buffer layer B-3 / PET / adhesive layer

[0147] (Formation of the adhesive layer) An acrylic polymer was obtained by copolymerizing 65 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 15 parts by mass of 2-hydroxyethyl acrylate (2HEA). 2-methacryloyloxyethyl isocyanate (MOI) was then reacted with the copolymer so as to add to 80 mol% of the total hydroxyl groups of the acrylic polymer, thereby obtaining an energy-ray curable acrylic resin (Mw: 500,000). To 100 parts by mass of this energy-ray curable acrylic resin, 6 parts by mass of a polyfunctional urethane acrylate, which is an energy-ray curable compound, 0.375 parts by mass of an isocyanate crosslinking agent ("Coronate L" manufactured by Tosoh Corporation), and 1 part by mass of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide as a photopolymerization initiator were added, and the mixture was diluted with methyl ethyl ketone to prepare a coating solution of an adhesive composition with a solid content of 32% by mass.

[0148] (Manufacturing of adhesive tape for semiconductor processing) A coating solution of the adhesive composition obtained above was applied to the release surface of a release sheet (Lintec Corporation, product name "SP-PET381031"), and then heated and dried to form an adhesive layer with a thickness of 30 μm on the release sheet. Then, an adhesive layer was bonded to the PET substrate side of the PET substrate with buffer layer A-1 formed in manufacturing example A1, thereby producing a semiconductor processing adhesive tape having a laminated structure of buffer layer A-1 / PET substrate / adhesive layer. Similarly, an adhesive layer was bonded to the PET substrate side of the PET substrate with buffer layer B-3 formed in comparative manufacturing example B3, thereby producing a semiconductor processing adhesive tape having a laminated structure of buffer layer B-3 / PET substrate / adhesive layer.

[0149] (evaluation) The semiconductor processing adhesive tapes of Example 1 exp. and Comparative Example 3 exp. were attached to a silicon wafer with a diameter of 12 inches and a thickness of 775 μm using a backgrind tape laminator (Lintec Corporation, model name "RAD-3510F / 12"). The semiconductor processing adhesive tape was then cut along the outer circumference of the silicon wafer with an art knife (OLFA Corporation, model number "XB10"). The art knife was inserted from the buffer layer side of the semiconductor processing adhesive tape. The angle between the buffer layer surface and the cutting edge of the blade was set to 57.2°. The cutting speed was set to 80 mm / s. The cross-section of the cut semiconductor processing adhesive tape was observed with a scanning electron microscope (SEM) and evaluated using the same criteria as for sheet cross-section evaluation (1).

[0150] Table 1 shows the results for the examples and comparative examples from "Evaluation of cutting performance by blades (1): Evaluation by simulation," and Table 2 shows the results for the reference example. Furthermore, the results of "Evaluation of cutting performance by blade (2): Experimental evaluation" are shown in Table 3. Furthermore, Figure 4 shows the analysis images of Example 1sim. and Comparative Example 3sim. in "Evaluation of Cutting Performance by Blade (1): Evaluation by Simulation," and Figure 5 shows the scanning electron microscope (SEM) observation results in "Evaluation of Cutting Performance by Blade (2): Evaluation by Experiment."

[0151] [Table 1]

[0152] [Table 2]

[0153] [Table 3]

[0154] From Table 1, the following can be seen. In Examples 1sim., 2sim., 3sim., and 4sim., where the buffer layer satisfies requirements (α) and (β), it can be seen that the cutting performance by the blade is good in all cases. In contrast, in Comparative Example 1sim. and Comparative Example 2sim., the buffer layer did not meet requirement (β), and it can be seen that both exhibited poor cutting performance with a blade. Furthermore, in Comparative Example 3sim., the buffer layer does not meet either requirement (α) or requirement (β), and it can be seen that the cutting performance with a blade is extremely poor.

[0155] From Table 2, the following can be seen. In both Reference Example 1sim. and Reference Example 2sim., where the substrate satisfies requirement (γ), it can be seen that the cutting performance by the blade is good. In this example, in reference example 2sim., the cutting performance by the blade is good despite not meeting requirement (β), which shows that the quality of the cutting performance of the substrate cannot be judged based on requirements (α) and (β).

[0156] From Table 3, the following can be seen. Table 3 shows Example 1 exp. and Comparative Example 3 exp., which are the results of experimental verification of Example 1 sim. and Comparative Example 3 sim. It can be seen that the evaluation results of the cutting performance by the blade examined in Example 1 exp. and Comparative Example 3 exp. are in complete agreement with the evaluation results of the cutting performance by the blade examined in Example 1 sim. and Comparative Example 3 sim. This is also evident from the results shown in Figures 4 and 5. [Explanation of Symbols]

[0157] 1. Adhesive tape for semiconductor processing 11 Buffer layer 12 Base material 13. Adhesive layer

Claims

1. It has a laminated structure in which a buffer layer, a substrate, and an adhesive layer are stacked in this order. A semiconductor processing adhesive tape wherein the buffer layer satisfies both of the following requirements (α) and (β). Requirement (α): The rupture energy of the buffer layer at 23°C is 15 MJ / m ３ That's all. Requirement (β): When the buffer layer is subjected to a tensile test at a temperature of 23°C, the fracture strain (ε １００ ) 80% strain (ε ８０ ) is the fracture strain (ε １００ The stress increase gradient Δρ until it increases to ). ８０－１００ However, it is 30 MPa or higher.

2. The semiconductor processing adhesive tape according to claim 1, wherein the substrate satisfies the following requirement (γ). • Requirement (γ): Fracture strain (ε) at a temperature of 23°C １００ ) and fracture stress (ρ) at a temperature of 23°C １００ The product of ( ) is 60 MPa or more.

3. The semiconductor processing adhesive tape according to claim 1 or 2, wherein the thickness of the adhesive layer is less than 100 μm.

4. A method for using the adhesive tape for semiconductor processing according to any one of claims 1 to 3, A method of use for backside grinding of a semiconductor wafer, comprising attaching the semiconductor processing adhesive tape to the surface of the semiconductor wafer and cutting the semiconductor processing adhesive tape along the outer circumference of the semiconductor wafer.

5. A method for manufacturing a semiconductor device, comprising the step (S1) of attaching a semiconductor processing adhesive tape according to any one of claims 1 to 3 to the surface of a semiconductor wafer, and cutting the semiconductor processing adhesive tape along the outer circumference of the semiconductor wafer.

6. In the method for manufacturing a semiconductor device according to claim 5, Furthermore, a method for manufacturing a semiconductor device, including the following step (S2). • Process (S2): A process of grinding the semiconductor wafer from the back side.

7. In the method for manufacturing a semiconductor device according to claim 6, Furthermore, a method for manufacturing a semiconductor device, including the following step (S3). • Process (S3): Process of dicing the semiconductor wafer to form individual pieces.

8. In the method for manufacturing a semiconductor device according to claim 6, As the semiconductor wafer, a semiconductor wafer having grooves formed on its surface is used. A manufacturing method comprising the above step (S2), wherein the semiconductor wafer is divided into a plurality of chips starting from the grooves.

9. In the method for manufacturing a semiconductor device according to claim 6, As the semiconductor wafer, a semiconductor wafer in which a modified region is formed internally is used, or a modified region is formed internally of the semiconductor wafer after the above step (S1). A manufacturing method comprising the above step (S2), wherein the semiconductor wafer is divided into a plurality of chips starting from the modified region.

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