Adhesive sheet for workpiece processing and method for manufacturing the same, and method for manufacturing an electronic device.

Abstract

The present invention provides an adhesive sheet for workpiece processing that suppresses peeling voltage, exhibits low odor and excellent abrasive properties, a method for manufacturing the same, and a method for manufacturing an electronic device using the adhesive sheet for workpiece processing. [Solution] The present invention relates to an adhesive sheet for workpiece processing, a method for manufacturing the same, and a method for manufacturing an electronic device using the adhesive sheet for workpiece processing, comprising a buffer layer, a base material, and an adhesive layer, wherein the adhesive layer is on one surface, the buffer layer is a layer containing a cured product of a thermosetting resin composition, and the thermosetting resin composition contains an antistatic agent.

Description

[Technical Field]

[0001] This invention relates to an adhesive sheet for workpiece processing, a method for manufacturing the same, and a method for manufacturing an electronic device. [Background technology]

[0002] As information terminal devices become thinner, smaller, and more multifunctional at an accelerating pace, electronic devices such as semiconductor equipment mounted on these devices are also required to be thinner and more densely packed. One method used to thin electronic devices has been to grind the back surface of workpieces such as semiconductor wafers used in the electronic devices. Back surface grinding of a workpiece is performed by attaching an adhesive sheet for back surface grinding (hereinafter also called a "back grind sheet") to the surface of the workpiece, and protecting the surface of the workpiece with the sheet. The back grind sheet is peeled off and removed from the surface of the workpiece after back surface grinding.

[0003] In recent years, pre-dicing and stealth pre-dicing methods have been put into practical use as grinding and dicing methods that reduce the thickness of workpieces while suppressing damage to the workpiece. The pre-dicing method involves forming a groove of a predetermined depth on the surface of the workpiece with a dicing blade or the like, and then grinding the workpiece from the back side down to the groove to dicate the workpiece into individual pieces. The stealth pre-dicing method involves forming a modified region inside the workpiece by irradiating it with laser light, and then grinding the workpiece from the back side, cleaving it using the modified region as the starting point for division to dicate the workpiece into individual pieces. In these methods as well, a back grind sheet is used to protect the surface of the workpiece.

[0004] For adhesive sheets used in workpiece processing, good grindability is required to stably hold the workpiece during processing and to suppress the occurrence of cracks or other damage to the workpiece. An example of an adhesive sheet for workpiece processing is an adhesive tape comprising a base material, a buffer layer provided on at least one side of the base material, and an adhesive layer provided on the other side of the base material, wherein the Young's modulus of the buffer layer at 23°C is 10 to 400 MPa and the breaking energy is 1 to 9 MJ / m 3 A semiconductor processing adhesive tape has been proposed in which the Young's modulus of the substrate at 23°C is greater than that of the buffer layer (see Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2020 / 003920 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the adhesive tape for semiconductor processing described in Patent Document 1, the buffer layer is provided to absorb vibrations generated during workpiece grinding and to mitigate unevenness caused by foreign matter, thereby stably and flatly holding the workpiece.

[0007] Incidentally, adhesive sheets for workpiece processing may emit odors due to their constituent components during manufacturing, storage, or use. In light of the growing awareness of the working environment, low odor properties are now required for adhesive sheets for workpiece processing. However, achieving excellent low odor while maintaining good workpiece grindability has been difficult. Furthermore, when peeling the adhesive sheet used for workpiece processing from the workpiece after processing, peeling static electricity may occur. If the peeling voltage becomes excessively high, it can lead to failure of circuits and other components formed on the workpiece, so it is desirable to suppress the peeling voltage.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide an adhesive sheet for work processing that suppresses peeling charging voltage, is excellent in low odor property and grindability, a method for producing the same, and a method for producing an electronic device using the adhesive sheet for work processing.

Means for Solving the Problems

[0009] As a result of intensive studies, the present inventors have found that the above problems can be solved by providing a buffer layer containing a cured product of a thermosetting resin composition containing a specific component in an adhesive sheet for work processing, and have completed the following present invention.

[0010] That is, the present invention relates to the following [1] to

[13] . [1] Having a buffer layer, a base material, and an adhesive layer, Having the adhesive layer on one surface, The buffer layer is a layer containing a cured product of a thermosetting resin composition, The thermosetting resin composition contains an antistatic agent, Adhesive sheet for work processing. [2] The antistatic agent is an ionic material, and the adhesive sheet for work processing according to [1] above. [3] The surface resistivity of the buffer layer is 1.0×10 12 Ω / sq. or less, and the adhesive sheet for work processing according to [1] or [2] above. [4] The thickness of the buffer layer is 2 to 100 μm, and the adhesive sheet for work processing according to any one of [1] to [3] above. [5] The thermosetting resin composition contains a polyester resin, and the adhesive sheet for work processing according to any one of [1] to [4] above. [6] The polyester resin is a polyester urethane resin, and the adhesive sheet for work processing according to [5] above. [7] The polyester resin is a polyester resin having two or more hydroxy groups, and the thermosetting resin composition further contains a polyvalent isocyanate compound, and the adhesive sheet for work processing according to [5] above. [8] The adhesive sheet for work processing according to any one of [1] to [7] above, having the buffer layer on one surface side of the base material and the adhesive layer on the other surface side of the base material. [9] The adhesive sheet for work processing according to any one of [1] to [8] above, which is used for grinding a work.

[10] The work has grooves on the surface or a modified region inside, While fixing the adhesive sheet for work processing affixed to the surface of the work, by grinding the back surface of the work, the work is used for fragmenting the work into a plurality of work pieces starting from the groove or the modified region, and is the adhesive sheet for work processing according to any one of [1] to [9] above.

[11] A method for manufacturing the adhesive sheet for work processing according to any one of [1] to

[10] above, A method for manufacturing an adhesive sheet for work processing, which has a step of curing by heating the thermosetting resin composition.

[12] A step of affixing the adhesive sheet for work processing according to any one of [1] to

[10] above to the surface of a work with the adhesive layer as the sticking surface, and A step of grinding the back surface of the work while fixing the adhesive sheet for work processing affixed to the work, A method for manufacturing an electronic device, which includes these steps.

[13] A step a of forming grooves on the surface of a work, or a step b of forming a modified region inside the work from the surface or the back surface of the work, which is a step of forming a division planned line, and After the step a, or before or after the step b, a step of affixing the adhesive sheet for work processing according to any one of [1] to

[10] above to the surface of the work with the adhesive layer as the sticking surface, which is a step of affixing a sheet, and A step of grinding and fragmenting the work by grinding the back surface of the work while fixing the adhesive sheet for work processing affixed to the work, so as to fragment the work into a plurality of work pieces starting from the groove or the modified region, A method for manufacturing an electronic device, which includes these steps.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide an adhesive sheet for workpiece processing that has suppressed peeling voltage, low odor, and excellent abrasive properties, as well as a method for manufacturing an electronic device using the adhesive sheet for workpiece processing. [Modes for carrying out the invention]

[0012] In this specification, the lower and upper limits described in steps for a preferred numerical range can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60," the "preferred lower limit (10)" and the "more preferred upper limit (60)" can be combined to arrive at "10 to 60."

[0013] In this specification, "active ingredient" refers to the components contained in the target composition, excluding the diluent solvent.

[0014] In this specification, the number-average molecular weight (Mn) and mass-average molecular weight (Mw) are values ​​on a standard polystyrene basis measured by gel permeation chromatography (GPC), specifically values ​​measured according to the method described in the Examples.

[0015] In this specification, for example, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid," and the same applies to other similar terms.

[0016] In this specification, "energy beam" means an electromagnetic wave or charged particle beam that has an energy quantum, and examples include ultraviolet light, radiation, and electron beams. Ultraviolet light can be irradiated using, for example, an electrodeless lamp, high-pressure mercury lamp, metal halide lamp, or UV-LED as an ultraviolet light source. Electron beams can be irradiated using those generated by an electron beam accelerator or the like. In this specification, "energy ray polymerizability" means the property of polymerizing when irradiated with energy rays. Furthermore, "energy ray curability" means the property of hardening when irradiated with energy rays, and "non-energy ray curability" means the property of not possessing energy ray curability.

[0017] In this specification, "workpiece" refers to a plate-like body to which the adhesive sheet for workpiece processing of this embodiment is attached and which is then processed. Examples of workpieces include wafers, panel-level packages, and strips (strip-shaped substrates) with molded resin encapsulation. Among these, wafers are preferred from the viewpoint of easily obtaining the effects of the present invention. The wafer may be a semiconductor wafer such as a silicon wafer, gallium arsenide wafer, silicon carbide wafer, gallium nitride wafer, or indium phosphate wafer, or an insulating wafer such as a glass wafer, lithium tantalate wafer, or lithium niobate wafer. It may also be a reconfigured wafer made of a resin and semiconductor used in the manufacture of a fan-out package or the like. Among these, from the viewpoint of easily obtaining the effects of the present invention, semiconductor wafers and insulating wafers are preferred as wafers, semiconductor wafers are more preferred, and silicon wafers are even more preferred. Circuits such as wiring, capacitors, diodes, and transistors are typically formed on the surface of semiconductor wafers. These circuits can be formed by conventionally known methods, such as etching and lift-off methods. The thickness of the workpiece before processing is not particularly limited, but is usually between 500 and 1,000 μm.

[0018] In this specification, "workpiece fragment" refers to a workpiece that has been divided. For example, if the workpiece is a semiconductor wafer, the workpiece fragment is a semiconductor chip; if the workpiece is a panel-level package or a strip (strip-shaped substrate) with molded resin encapsulation, the workpiece fragment is a semiconductor package.

[0019] In this specification, "electronic device apparatus" refers to, for example, a workpiece, a workpiece fragment, an electronic component containing the workpiece fragment, or an electronic device equipped with the electronic component.

[0020] In this specification, the "front surface" of a workpiece refers to the surface on which a circuit is formed, and the "back surface" refers to the surface on which no circuit is formed.

[0021] The mechanism of action described herein is speculative and does not limit the mechanism by which the adhesive sheet for workpiece processing of the present invention achieves its effect.

[0022] [Adhesive sheet for workpiece processing] The adhesive sheet for workpiece processing in this embodiment (hereinafter also referred to as the "adhesive sheet") is It has a buffer layer, a base material, and an adhesive layer, The adhesive layer is present on one surface, The buffer layer is a layer containing a cured product of a thermosetting resin composition, The thermosetting resin composition contains an antistatic agent. This is an adhesive sheet for workpiece processing.

[0023] The adhesive sheet of this embodiment is attached to the surface of a workpiece and used to perform a predetermined process on the workpiece while protecting the surface. After the predetermined process has been performed on the workpiece, the adhesive sheet of this embodiment is peeled off and removed from the workpiece.

[0024] The laminated structure of the adhesive sheet in this embodiment is not particularly limited as long as it has an adhesive layer on one surface and the adhesive layer can be attached to a workpiece. For example, the substrate may have a buffer layer on one side and an adhesive layer on the other side, or the substrate, buffer layer, and adhesive layer may be arranged in this order. Among these, from the viewpoint of easily obtaining better grindability, the substrate with a buffer layer on one side and an adhesive layer on the other side is preferred.

[0025] The adhesive sheet of this embodiment may have layers other than the buffer layer, base material, and adhesive layer, or it may not have layers other than the buffer layer, base material, and adhesive layer. Examples of layers other than the buffer layer, substrate, and adhesive layer include an intermediate layer provided between the substrate and the adhesive layer, and a release sheet provided on the surface of the adhesive sheet. The following describes each component that makes up the adhesive sheet of this embodiment.

[0026] <Buffer layer> The adhesive sheet of this embodiment has a buffer layer that absorbs vibrations, shocks, etc. that occur when grinding or other processing is performed on the workpiece, thereby preventing cracks from occurring in the workpiece. Furthermore, by providing a buffer layer, it is also possible to absorb irregularities such as foreign matter present on the table of the support device, thereby improving the ability of the support device to hold the adhesive sheet.

[0027] The buffer layer of the adhesive sheet of this embodiment is a layer containing a cured product of a thermosetting resin composition, the thermosetting resin composition containing an antistatic agent. By forming the buffer layer from a thermosetting resin composition containing an antistatic agent, the adhesive sheet of this embodiment has a suppressed peel voltage. Furthermore, because the buffer layer of the adhesive sheet of this embodiment contains an antistatic agent, it is possible to suppress the decrease in adhesive strength and contamination of the workpiece by the antistatic agent that may occur when the antistatic agent is contained in the adhesive layer. Furthermore, the raw materials constituting the thermosetting resin composition form a cross-linked structure upon heating, and since odor-causing raw materials are less likely to remain during this process, the odor of the buffer layer is suppressed, resulting in excellent low-odor properties. In addition, the good shape retention due to the cross-linked structure of the cured product of the thermosetting resin composition allows for good hold on the workpiece during grinding, resulting in excellent grindability.

[0028] The buffer layer of the adhesive sheet in this embodiment may be a layer containing a cured product of a thermosetting resin composition, but from the viewpoint of low odor and abrasive properties, it is preferable that it be a cured product of a layer formed from a thermosetting resin composition. The above thermosetting resin composition will be described in detail below.

[0029] (Thermosetting resin composition) The thermosetting resin composition is not particularly limited as long as it is a resin composition that has thermosetting properties. The thermosetting resin contained in the thermosetting resin composition may exhibit thermosetting properties on its own, or it may exhibit thermosetting properties when used in combination with one or more elements selected from the group consisting of crosslinking agents and catalysts.

[0030] [Thermosetting resin] Examples of thermosetting resins include epoxy resins, phenolic resins, silicone resins, melamine resins, acrylic resins, and polyester resins. Among these, polyester resins are preferred from the viewpoint of low odor and abrasive properties. Thermosetting resins may be used individually or in combination of two or more types.

[0031] Examples of polyester resins include polymers obtained by condensation polymerization of an alcohol component such as ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol, hydrogenated bisphenol A, or an ethylene oxide or propylene oxide adduct of bisphenol A, and a carboxylic acid component such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, adipic acid, azelaic acid, maleic acid, fumaric acid, itaconic acid, or their acid anhydrides. The alcohol component and the carboxylic acid component may be used individually or in combination of two or more.

[0032] The polyester resin may be a resin modified from polyester, and from the viewpoint of low odor and abrasive properties, it is preferably a polyester-urethane resin obtained by modifying polyester with urethane. In this specification, polyester-urethane resin is encompassed within the concept of polyester resin, and preferred embodiments of polyester resin can be read as preferred embodiments of polyester-urethane resin. Examples of polyester urethane resins include those obtained by reacting a polyvalent isocyanate compound with a polyester polyol having hydroxyl groups at its ends, which is obtained by condensation polymerization of the above-mentioned alcohol component and the above-mentioned carboxylic acid component. The polyvalent isocyanate compound used as a raw material component for polyester urethane resin may be any of the following: aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, or alicyclic polyvalent isocyanate compounds. Specific examples of such polyvalent isocyanate compounds include diphenylmethane diisocyanate, tolylene diisocyanate, 1,3-xylylene diisocyanate, isophorone diisocyanate, and 1,6-hexane diisocyanate. Polyester polyols and polyvalent isocyanate compounds, used as raw material components for polyester urethane resin, may be used individually or in combination of two or more types.

[0033] Polyester resins have reactive functional groups for thermosetting, and from the viewpoint of improving thermosetting properties, those having two or more hydroxyl groups are preferred, and those having two or more hydroxyl groups at the molecular ends are more preferred. The "molecular ends" of a polyester resin refer to both ends if the polyester resin is linear, and also include the ends of the branched chains if the polyester resin has branched chains. Among these, polyester resins that are linear and have hydroxyl groups at both ends are preferred.

[0034] The glass transition temperature (Tg) of the polyester resin is not particularly limited, but is preferably 50 to 140°C, more preferably 60 to 120°C, even more preferably 70 to 110°C, and even more preferably 75 to 100°C. When the glass transition temperature (Tg) of the polyester resin is above the lower limit, it tends to suppress excessive deformation of the buffer layer when processing the workpiece. Furthermore, when the glass transition temperature (Tg) of the polyester resin is below the upper limit, it tends to improve the effect of absorbing vibrations and shocks generated during grinding of the workpiece, as well as the retention of the adhesive sheet. The glass transition temperature (Tg) of polyester resins can be measured in accordance with JIS K 7121:2012.

[0035] The number-average molecular weight (Mn) of the polyester resin is not particularly limited, but is preferably 5,000 to 100,000, more preferably 10,000 to 70,000, even more preferably 15,000 to 50,000, and even more preferably 30,000 to 48,000. When the number-average molecular weight (Mn) of the polyester resin is above the lower limit, it tends to suppress excessive deformation of the buffer layer when processing the workpiece. Furthermore, when the number-average molecular weight (Mn) of the polyester resin is below the upper limit, it tends to improve the effect of absorbing vibrations and shocks generated during grinding of the workpiece, as well as the retention of the adhesive sheet.

[0036] The hydroxyl value of the polyester resin is not particularly limited, but is preferably 0.5 to 30 KOH mg / g, more preferably 1 to 20 KOH mg / g, even more preferably 2 to 10 KOH mg / g, and even more preferably 2 to 5 KOH mg / g. When the hydroxyl value of the polyester resin is above the lower limit, thermosetting properties improve, odor reduction is enhanced, and excessive deformation of the buffer layer during workpiece processing tends to be suppressed. Furthermore, when the hydroxyl value of the polyester resin is below the upper limit, the effect of absorbing vibrations and shocks generated during workpiece grinding and the retention of the adhesive sheet tend to improve. The hydroxyl value of polyester resins can be measured in accordance with JIS K 0070:1992.

[0037] When the thermosetting resin composition contains a polyester resin, the amount of polyester resin in the thermosetting resin composition is not particularly limited, but is preferably 30 to 98% by mass, more preferably 50 to 98% by mass, and even more preferably 70 to 98% by mass, based on the total amount of solids (100% by mass) of the thermosetting resin composition. When the polyester resin content falls within the above range, there is a tendency for the odor and abrasive properties to be better. In this specification, "total solid content of the thermosetting resin composition" refers to components other than the solvent contained in the thermosetting resin composition, and components other than the solvent are considered to be solid content even if they are liquid at room temperature (23°C).

[0038] While extrusion molding is commonly used to mold polyester resins, it requires heating the polyester resin to high temperatures, resulting in significant equipment and energy loads and making it difficult to achieve good productivity. Furthermore, problems specific to extrusion molding, such as the formation of lumps known as "fish eyes," can occur, making it difficult to obtain excellent quality stability. In contrast, the adhesive sheet of this embodiment uses polyester resin as a raw material for a thermosetting resin composition, allowing for the formation of a homogeneous buffer layer under relatively mild heating conditions. Therefore, the adhesive sheet of this embodiment offers excellent productivity and quality stability.

[0039] [Antistatic agent] The thermosetting resin composition contains an antistatic agent. While not particularly limited, antistatic agents include ionic materials, nonionic materials, amphoteric materials, metal salts, and carbon nanotubes. Among these, ionic materials are preferred from the viewpoint of more effectively suppressing the delamination band voltage. Antistatic agents may be used individually or in combination of two or more types.

[0040] Ionic materials are ion-pair compounds composed of cations and anions. Examples of cations that constitute ionic materials include ammonium cations, imidazolium cations, phosphonium cations, pyridinium cations, pyrrolidinium cations, pyrrolinium cations, and triazonium cations. These cations may be used individually or in combination of two or more.

[0041] Among these, from the viewpoint of having excellent antistatic performance, it is preferable that the cation constituting the ionic material is at least one selected from the group consisting of ammonium cations, imidazolium cations, and pyridinium cations.

[0042] Examples of the above-mentioned ammonium cations include cations derived from alkanolamine salt reaction products (alkanolamine cations), butyltrimethylammonium cations, triethylpropylammonium cations, 2-hydroxyethyl-triethylammonium cations, methyltrioctylammonium cations, tetrabutylammonium cations, tetraethylammonium cations, tetraheptylammonium cations, tributylmethylammonium cations, triethylmethylammonium cations, tris(2-hydroxy)methylammonium cations, and ammonium cations. Ammonium cations may be used individually or in combination of two or more.

[0043] Examples of the imidazolium-based cations mentioned above include 1-allyl-3-methylimidazolium cation, 1-benzyl-3-methylimidazolium cation, 1,3-bis(cyanomethyl)imidazolium cation, 1,3-bis(cyanopropyl)imidazolium cation, and 1-butyl-2,3-dimethylimidazolium cation. One type of imidazolium-based cation may be used alone, or two or more types may be used in combination.

[0044] Examples of the pyridinium-based cations mentioned above include 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, and 1-octyl-4-methylpyridinium cation. A single pyridinium-based cation may be used, or two or more may be used in combination.

[0045] Examples of anions that constitute ionic materials include sulfonate anions, carboxylate anions, carbonate anions, amide anions, phosphate anions, thiocyanate anions, nitrate anions, and borate anions. These anions may be used individually or in combination of two or more.

[0046] Among these, from the viewpoint of having excellent antistatic performance, it is more preferable that the anions constituting the ionic material be at least one selected from the group consisting of sulfonate anions, borate anions, and phosphate anions.

[0047] Examples of the above-mentioned sulfonate anions include anions derived from the reaction products of glycol ether sulfate (glycol ether sulfate anions), anions derived from the reaction products of alkylbenzene sulfonic acid (alkylbenzene sulfonic acid anions), butyl sulfonate anions, methyl sulfonate anions, ethyl sulfonate anions, hydrogen sulfonate anions, octyl sulfonate anions, alkyl sulfonate anions, and dialkyl succinate sulfonic acid anions. The sulfonate anions may be used individually or in combination of two or more.

[0048] Examples of the borate anions mentioned above include the borate anion represented by the following formula (1), in which four groups are bonded to a boron atom. (R 1 )(R 2 )B-(R 3 )(R4 ) (1) In the above formula (1), R 1 and R 2 in the group consisting of, and R 3 and R 4 in the group consisting of, at least one of the groups combines with each other to form a monocyclic ring, combines with each other to form a condensed ring, or does not combine with each other, and R 1 , R 2 , R 3 , and R 4 are each independently an organic group having 1 to 20 carbon atoms that does not contain a saturated or unsaturated heteroatom, or an organic group having 1 to 20 carbon atoms that contains a saturated or unsaturated heteroatom. R 1 , R 2 , R 3 and R 4 The organic groups represented by are each independently any group selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, and a heterocyclic group, and may contain a heteroatom. Examples of the heteroatom include at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. The borate-based anion represented by the above formula (1) may be a complex anion. The borate-based anion may be used alone or in combination of two or more.

[0049] Examples of the phosphate-based anion include alkyl phosphate anions such as ethyl phosphate anion and dimethyl phosphate anion. The phosphate-based anion may be used alone or in combination of two or more. <00002​​​​​​The content of the antistatic agent in the thermosetting resin composition is not particularly limited, but is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 40 parts by mass, even more preferably 1 to 30 parts by mass, and even more preferably 2 to 25 parts by mass per 100 parts by mass of the thermosetting resin. Furthermore, the content of the antistatic agent in the thermosetting resin composition is not particularly limited, but is preferably 0.1 to 45% by mass, more preferably 0.4 to 35% by mass, even more preferably 0.8 to 25% by mass, and even more preferably 1.5 to 20% by mass, based on the total solid content (100% by mass) of the thermosetting resin composition. When the antistatic agent content is above the lower limit, the delamination voltage tends to be suppressed more effectively. Conversely, when the antistatic agent content is below the upper limit, the dispersibility of the antistatic agent in the thermosetting resin composition tends to be better.

[0052] [Crosslinking agent] The thermosetting resin composition may optionally contain a crosslinking agent for crosslinking the thermosetting resin. The crosslinking agent may be used alone or in combination of two or more types. The crosslinking agent can be a known compound depending on the type of reactive group present in the thermosetting resin to be crosslinked. Examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, amine-based crosslinking agents, melamine-based crosslinking agents, aziridine-based crosslinking agents, hydrazine-based crosslinking agents, aldehyde-based crosslinking agents, oxazoline-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, and ammonium salt-based crosslinking agents. Among the crosslinking agents mentioned above, when the thermosetting resin composition contains a polyester resin having two or more hydroxyl groups, an isocyanate-based crosslinking agent is preferred from the viewpoint of improving thermosetting properties. The isocyanate-based crosslinking agent is preferably a polyvalent isocyanate compound. Since polyvalent isocyanate compounds are reactive with hydroxyl groups, they can bond with polyester resins having hydroxyl groups to form a crosslinked structure. The number of isocyanate groups in a polyvalent isocyanate compound may be, for example, two or three, or three or more, depending on the type of thermosetting resin to be crosslinked.

[0053] Examples of polyvalent isocyanate compounds include aromatic isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, 1,3,5-triisocyanate benzene, 1,3,5-triisocyanate methylbenzene, 2,4,6-triisocyanate toluene, and triphenylmethane-4,4',4''-triisocyanate; alicyclic isocyanate compounds such as dicyclohexylmethane-4,4'-diisocyanate, bicycloheptane triisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and hydrogenated xylylene diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. Furthermore, the polyvalent isocyanate compound may be a modified form of the compounds exemplified above, such as the biuret or isocyanurate form; or an adduct form obtained by reacting these compounds with non-aromatic low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, trimethylolpropane, or castor oil. Among these, the adduct of trimethylolpropane is preferred from the viewpoint of easily obtaining good reactivity.

[0054] When a thermosetting resin composition contains a polyester resin having two or more hydroxyl groups and a polyvalent isocyanate compound, the content of the polyvalent isocyanate compound in the thermosetting resin composition is not particularly limited, but is preferably 1 to 15 parts by mass per 100 parts by mass of the polyester resin having two or more hydroxyl groups. When the content of polyvalent isocyanate compounds is within the above range, the low odor and abrasive properties of the adhesive sheet tend to be better.

[0055] [Curing catalyst] The thermosetting resin composition may optionally contain a curing catalyst to accelerate the thermosetting reaction of the thermosetting resin. The curing catalyst may be used alone or in combination of two or more types. Examples of curing catalysts include organometallic compounds and tertiary amine compounds. Among these, organometallic compounds are preferred from the viewpoint of reactivity. As organometallic compounds, tin-based organometallic compounds are preferred, such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin bis(2-ethylhexanoate), dibutyltin dieodecanoate, dioctyltin diacetate, dioctyltin dioctoate, dioctyltin dilaurate, dioctyltin bis(2-ethylhexanoate), and dioctyltin dieodecanoate. Among these, dioctyltin dilaurate is preferred from the viewpoint of reactivity. Other organometallic compounds include, for example, metal acylates (e.g., octolic acid compounds, naphthenic acid compounds, stearic acid compounds, etc.) of bismuth, titanium, zirconium, zinc, iron, etc., metal chelates, metal alkoxides, etc. These may be used individually or in combination of two or more.

[0056] When a thermosetting resin composition contains a curing catalyst, the amount of curing catalyst in the thermosetting resin composition is not particularly limited, but is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and even more preferably 0.1 to 1 part by mass per 100 parts by mass of the thermosetting resin. When the content of the curing catalyst is within the above range, the thermosetting reaction can proceed homogeneously and sufficiently.

[0057] [Other ingredients] The thermosetting resin composition may contain other components as long as they do not impair the effects of the present invention. Examples of other components include resin components other than those described above; antioxidants, softeners, fillers, rust inhibitors, pigments, dyes, and other additives.

[0058] (Thickness of the buffer layer) The thickness of the buffer layer is not particularly limited, but is preferably 2 to 100 μm, more preferably 5 to 80 μm, even more preferably 10 to 70 μm, and even more preferably 20 to 60 μm. When the thickness of the buffer layer is greater than or equal to the lower limit mentioned above, the effect of absorbing vibrations and shocks generated during workpiece grinding and the retention of the adhesive sheet tend to be higher. Conversely, when the thickness of the buffer layer is less than or equal to the upper limit mentioned above, excessive deformation of the buffer layer during workpiece processing can be suppressed, and it also tends to be more economical.

[0059] (Surface resistivity of the buffer layer) The surface resistivity of the buffer layer of the adhesive sheet in this embodiment is preferably 1.0 × 10⁻⁶. 12 Ω / sq. or less, more preferably 5.0 × 10 11 Ω / sq. or less, more preferably 1.0 × 10⁻⁶ 11 Ω / sq. or less, more preferably 5.0 × 10 10 It is less than or equal to Ω / sq. When the surface resistivity of the buffer layer is below the above upper limit, the delamination voltage tends to be suppressed more effectively. A lower surface resistivity for the buffer layer is preferable, but 1.0 × 10 7 It may be greater than or equal to Ω / sq., and 1.0 × 10 8 It may be greater than or equal to Ω / sq., and 1.0 × 10 9 It may be Ω / sq. or greater. The surface resistivity of the buffer layer can be measured by the method described in the examples.

[0060] <Adhesive layer> The adhesive layer is not particularly limited, but it is preferably a layer formed from an energy-ray curable adhesive. By forming the adhesive layer from an energy-ray curable adhesive, the workpiece surface can be well protected by sufficient tackiness before energy-ray curing, and the peeling force is reduced after energy-ray curing, making it easy to peel off from the workpiece.

[0061] Examples of energy-ray curable adhesives include the following X-type adhesive composition, Y-type adhesive composition, XY-type adhesive composition, etc. Type X adhesive composition: An energy-ray curable adhesive composition containing a non-energy-ray curable adhesive resin (hereinafter also referred to as "adhesive resin I") and an energy-ray curable compound other than the adhesive resin. Y-type adhesive composition: An energy-ray curable adhesive composition containing an energy-ray curable adhesive resin (hereinafter also referred to as "adhesive resin II") in which an unsaturated group is introduced into the side chain of a non-energy-ray curable adhesive resin, and which does not contain any energy-ray curable compounds other than the adhesive resin. XY-type adhesive composition: An energy-ray curable adhesive composition containing the above-mentioned energy-ray curable adhesive resin II and an energy-ray curable compound other than the adhesive resin. Among these, energy-ray curable adhesives are preferably XY-type adhesive compositions. By using an XY-type adhesive composition, it is possible to have sufficient tackiness before curing while significantly reducing the peeling force from the workpiece after curing.

[0062] The adhesive forming the adhesive layer may be a layer formed from a non-energy-ray curable adhesive that does not harden when irradiated with energy rays. Examples of non-energy-ray curable adhesives include those that contain adhesive resin I but do not contain adhesive resin II or energy-ray curable compounds.

[0063] Next, we will explain in more detail each component that makes up the adhesive layer. In the following description, "adhesive resin" is used to refer to either or both of Adhesive Resin I and Adhesive Resin II. Furthermore, in the following description, when simply referred to as "adhesive composition," the term includes X-type adhesive composition, Y-type adhesive composition, XY-type adhesive composition, and other adhesive compositions.

[0064] Examples of adhesive resins include acrylic resins, urethane resins, rubber resins, and silicone resins. Among these, acrylic resins are preferred.

[0065] (Acrylic resin) The acrylic resin preferably contains constituent units derived from alkyl (meth)acrylate. Examples of alkyl (meth)acrylates include alkyl (meth)acrylates in which the alkyl group has 1 to 20 carbon atoms. The alkyl group in the alkyl (meth)acrylate may be linear or branched.

[0066] From the viewpoint of further improving the adhesive strength of the adhesive layer, it is preferable that the acrylic resin contains constituent units derived from alkyl (meth)acrylates in which the alkyl group has 4 or more carbon atoms. The constituent units derived from alkyl (meth)acrylates containing alkyl groups with 4 or more carbon atoms in the acrylic resin may be one type alone or two or more types. The alkyl(meth)acrylate having four or more carbon atoms in the alkyl group preferably has 4 to 12 carbon atoms, more preferably 4 to 8 carbon atoms, and even more preferably 4 to 6 carbon atoms. Examples of alkyl (meth)acrylates having four or more carbon atoms in the alkyl group include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. Among these, butyl (meth)acrylate is preferred, and butyl acrylate is more preferred. When the acrylic resin contains constituent units derived from alkyl (meth)acrylate having four or more carbon atoms in the alkyl group, the content thereof is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and even more preferably 45 to 60% by mass, in the acrylic resin, from the viewpoint of further improving the adhesive strength of the adhesive layer.

[0067] From the viewpoint of improving the storage modulus G' and adhesive properties of the adhesive layer, it is preferable that the acrylic resin contains both structural units derived from alkyl (meth)acrylates having 4 or more carbon atoms in the alkyl group, and structural units derived from alkyl (meth)acrylates having 1 to 3 carbon atoms in the alkyl group. The constituent units derived from alkyl (meth)acrylates containing alkyl groups with 1 to 3 carbon atoms in the acrylic resin may be one type alone or two or more types. Examples of alkyl(meth)acrylates having 1 to 3 carbon atoms in the alkyl group include methyl(meth)acrylate, ethyl(meth)acrylate, isopropyl(meth)acrylate, and n-propyl(meth)acrylate. Among these, methyl(meth)acrylate and ethyl(meth)acrylate are preferred, methyl(meth)acrylate is more preferred, and methyl methacrylate is even more preferred. When the acrylic resin contains constituent units derived from alkyl (meth)acrylates having 1 to 3 carbon atoms in the alkyl group, the content of these units is preferably 1 to 35% by mass, more preferably 5 to 30% by mass, and even more preferably 15 to 25% by mass, in the acrylic resin.

[0068] The acrylic resin preferably further contains constituent units derived from functional group-containing monomers. By containing structural units derived from functional group-containing monomers in acrylic resins, it is possible to introduce functional groups that act as crosslinking starting points that react with crosslinking agents, or functional groups that react with unsaturated group-containing compounds to introduce unsaturated groups into the side chains of the acrylic resin. The constituent units derived from functional group-containing monomers contained in the acrylic resin may be one type alone or two or more types.

[0069] Examples of functional group-containing monomers include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers. Among these, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferred, and hydroxyl group-containing monomers are more preferred. 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; unsaturated alcohols such as vinyl alcohol and allyl alcohol; and the like. 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; and 2-carboxyethyl methacrylate.

[0070] When an acrylic resin contains constituent units derived from functional group-containing monomers, the content is not particularly limited, but is preferably 5 to 45% by mass, more preferably 15 to 40% by mass, in the acrylic resin.

[0071] In addition to the above-mentioned structural units, the acrylic resin may also contain structural units derived from other monomers copolymerizable with acrylic monomers. The constituent units derived from other monomers contained in the acrylic resin may be one type alone or two or more types. Other monomers include, for example, styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide.

[0072] The acrylic resin may also be modified by introducing unsaturated groups that are capable of energy ray polymerization in order to impart energy ray curability. Unsaturated groups can be introduced, for example, by reacting a functional group of an acrylic resin containing a structural unit derived from a functional group-containing monomer with a reactive substituent of a compound having a reactive substituent and an unsaturated group that are reactive with the functional group (hereinafter also referred to as an "unsaturated group-containing compound"). The unsaturated group-containing compound may be used alone or in combination of two or more types. Examples of unsaturated groups found in compounds containing unsaturated groups include (meth)acryloyl groups, vinyl groups, and allyl groups. Among these, (meth)acryloyl groups are preferred. Examples of reactive substituents found in unsaturated group-containing compounds include isocyanate groups and glycidyl groups. Examples of compounds containing unsaturated groups include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and glycidyl (meth)acrylate.

[0073] When an acrylic resin containing structural units derived from functional group-containing monomers is reacted with an unsaturated group-containing compound, the ratio of functional groups that react with the unsaturated group-containing compound to the total number of functional groups in the acrylic resin is not particularly limited, but is preferably 60 to 98 mol%, more preferably 70 to 95 mol%, and even more preferably 80 to 93 mol%. When the ratio of functional groups that react with the unsaturated group-containing compound is within the above range, sufficient energy ray curability can be imparted to the acrylic resin, and the functional groups that did not react with the unsaturated group-containing compound can be reacted with the crosslinking agent to crosslink the acrylic resin.

[0074] The mass-average molecular weight (Mw) of the acrylic resin is not particularly limited, but is preferably 300,000 to 1,500,000, more preferably 350,000 to 1,000,000, and even more preferably 400,000 to 600,000. When the mass-average molecular weight (Mw) of the acrylic resin is within the above range, the adhesive strength and cohesive strength of the adhesive layer tend to be better.

[0075] (Energy ray curable compound) As the energy-ray 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 being cured by energy-ray irradiation are preferred. Examples of energy-ray curable compounds include polyvalent (meth)acrylate monomers such as trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate; and oligomers such as urethane(meth)acrylate, polyester(meth)acrylate, polyether(meth)acrylate, and epoxy(meth)acrylate. Among these, urethane(meth)acrylate oligomers are preferred from the viewpoint of having a relatively high molecular weight and not easily reducing the elastic modulus of the adhesive layer.

[0076] The molecular weight of the energy-ray-curable compound is not particularly limited, but 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. When the energy-ray-curable compound is an oligomer, the above molecular weight refers to the mass-average molecular weight (Mw).

[0077] The content of the energy ray curable compound in the XY-type adhesive composition is not particularly limited, but 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 adhesive resin. When the content of the energy-ray-curable compound in the XY-type adhesive composition is within the above range, a good balance between the adhesive strength before energy irradiation and the peelability after energy irradiation tends to be achieved. Furthermore, because the adhesive resin in the XY-type adhesive composition is energy-ray-curable, even with a low content of the energy-ray-curable compound, the peelability after energy irradiation tends to be sufficiently reduced.

[0078] (Crosslinking agent) The adhesive composition preferably further contains a crosslinking agent. A crosslinking agent, for example, crosslinks adhesive resins by reacting with functional groups derived from functional group-containing monomers present in the adhesive resin. The crosslinking agent may be used alone or in combination of two or more types.

[0079] 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]triphosphatriadin; and chelate-based crosslinking agents such as aluminum chelate. Among these, isocyanate-based crosslinking agents are preferred from the viewpoint of increasing cohesive force and improving adhesion, as well as from the viewpoint of availability.

[0080] When the adhesive composition contains a crosslinking agent, the amount is not particularly limited, but from the viewpoint of allowing the crosslinking reaction to proceed appropriately, it 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.

[0081] (Photopolymerization initiator) When the adhesive is an energy-ray curable adhesive, it is preferable that the adhesive composition further contains a photopolymerization initiator. The presence of a photopolymerization initiator in an energy-ray curable adhesive tends to allow the curing reaction to proceed sufficiently even with relatively low-energy energy rays such as ultraviolet light. The photopolymerization initiator may be used alone or in combination of two or more types.

[0082] 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.

[0083] When the adhesive composition contains a photopolymerization initiator, the amount is not particularly limited, but from the viewpoint of ensuring that the energy ray curing reaction proceeds homogeneously and sufficiently, it 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 5 parts by mass per 100 parts by mass of adhesive resin.

[0084] (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, softeners, fillers, rust inhibitors, pigments, dyes, and the like.

[0085] (organic solvent) The adhesive composition may be diluted with an organic solvent to form a solution, from the viewpoint of further improving its applicability to substrates, release sheets, etc. Examples of organic solvents include those similar to those that may be contained in the thermosetting resin composition described later. The organic solvent may be the same as that used during the synthesis of the adhesive resin, or one or more organic solvents other than those used during synthesis may be added.

[0086] The thickness of the adhesive layer is not particularly limited, but is preferably 5 to 100 μm, more preferably 10 to 80 μm, and even more preferably 15 to 60 μm. When the thickness of the adhesive layer is greater than or equal to the lower limit mentioned above, excellent adhesion is obtained, and the surface of the workpiece tends to be better protected during processing. Conversely, when the thickness of the adhesive layer is less than or equal to the upper limit mentioned above, the generation of tape scraps when cutting the adhesive sheet is suppressed, and damage to the workpiece tends to be better prevented.

[0087] <Base material> Examples of substrates include various resin films. Examples of resins constituting the resin films 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; polyurethane, polyimide, polyamide, polycarbonate, fluororesin, polyacetal, modified polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether ketone, and acrylic polymers. The substrate may be a single-layer resin film made of one or more resins selected from these resins, or a laminated film made by laminating two or more of these resin films. Alternatively, it may be a modified film such as a crosslinked film or ionomer film of the above resins. Among these resin films, the base material is preferably one or more selected from polyester film, polyamide film, polyimide film, and biaxially oriented polypropylene film, with polyester film being more preferred and polyethylene terephthalate film being even more preferred.

[0088] The Young's modulus of the substrate is not particularly limited, but is preferably 1,000 MPa or more, more preferably 1,800 to 30,000 MPa, and even more preferably 2,500 to 6,000 MPa. The Young's modulus of the substrate can be measured in accordance with JIS K 7127:1999 under conditions of a test speed of 200 mm / min.

[0089] The thickness of the substrate is not particularly limited, but is preferably 10 to 200 μm, more preferably 25 to 100 μm, and even more preferably 30 to 70 μm. When the thickness of the base material is greater than or equal to the lower limit mentioned above, sufficient strength for functioning as a support for the adhesive sheet tends to be obtained. Conversely, when the thickness of the base material is less than or equal to the upper limit mentioned above, moderate flexibility is obtained, and handling tends to improve. Note that "base material thickness" refers to the total thickness of the base material. If the base material consists of multiple layers, it refers to the total thickness of all the layers that make up the base material.

[0090] The base material may contain plasticizers, lubricants, infrared absorbers, ultraviolet absorbers, fillers, colorants, antistatic agents, antioxidants, catalysts, etc., to the extent that it does not impair the effects of the present invention. The substrate may be transparent or opaque, and may be colored or vapor-deposited as desired. The substrate may have surface treatment, such as corona treatment, applied to at least one surface, from the viewpoint of improving adhesion with other layers, or it may have a coating layer provided for the purpose of improving adhesion.

[0091] <Release sheet> The release sheet is attached to the surface of the adhesive sheet before use in a removable manner to protect the surface, and is peeled off and removed when the adhesive sheet is to be used. The release sheet may be a release sheet that has been treated to peel on one side, or a release sheet that has been treated to peel on both sides. Preferably, the release sheet is a release sheet in which a release agent, such as a silicone resin, is applied to a release sheet substrate. The release sheet substrate is the same as the one exemplified as the substrate of the adhesive sheet in this embodiment.

[0092] <Total thickness of adhesive sheet> The total thickness of the adhesive sheet in this embodiment is not particularly limited, but is preferably 30 to 300 μm, more preferably 40 to 220 μm, and even more preferably 45 to 180 μm. When the total thickness of the adhesive sheet is above the lower limit, the adhesive performance of the adhesive layer and the shock absorption performance of the buffer layer are appropriately maintained, and the adhesive sheet tends to fully perform its function as an adhesive sheet for workpiece processing. Conversely, when the total thickness of the adhesive sheet is below the upper limit, the peeling force required when peeling the workpiece from the adhesive sheet tends to be reduced. In the case where a release liner is provided on the adhesive sheet of this embodiment, the thickness of the release liner is not included in the "total thickness of the adhesive sheet."

[0093] [Method for manufacturing adhesive sheets] The method for manufacturing the adhesive sheet of this embodiment includes a step of curing a thermosetting resin composition by heating it (hereinafter also referred to as the "thermosetting step"). This thermosetting step allows for the formation of the buffer layer of the adhesive sheet of this embodiment.

[0094] The thermosetting process is preferably a process of curing a coating film formed by applying a thermosetting resin composition by heating it. When applying a thermosetting resin composition, it is preferable to use the thermosetting resin composition in the form of a solution diluted with an organic solvent. Dilution with an organic solvent facilitates the application process and makes it easier to adjust the thickness of the buffer layer, enabling the formation of a buffer layer with excellent thickness accuracy, even if it is thin. Examples of organic solvents include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. One organic solvent may be used alone, or two or more may be used in combination. The content of the organic solvent in the thermosetting resin composition diluted with the organic solvent is not particularly limited, but is preferably 40 to 90% by mass, more preferably 50 to 85% by mass, and even more preferably 60 to 80% by mass.

[0095] The thermosetting resin composition may be applied to a release sheet, or it may be applied directly to the surface of the substrate or adhesive layer. Methods for applying thermosetting resin compositions include, for example, spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, and gravure coating.

[0096] The heating temperature of the thermosetting resin composition is preferably 80 to 150°C, more preferably 90 to 140°C, and even more preferably 100 to 130°C, from the viewpoint of the productivity of the adhesive sheet and sufficient curing of the thermosetting resin composition. Furthermore, the heating time for the thermosetting resin composition is preferably 0.1 to 60 minutes, more preferably 0.3 to 30 minutes, and even more preferably 0.5 to 5 minutes, from the viewpoint of the productivity of the adhesive sheet and sufficient curing of the thermosetting resin composition. When a release sheet with a buffer layer is obtained by applying a thermosetting resin composition onto a release sheet, the buffer layer of the release sheet with a buffer layer can then be attached to the surface of the substrate or adhesive layer.

[0097] In the method for manufacturing the adhesive sheet of this embodiment, the method for forming the adhesive layer is not particularly limited, but one example is to apply the above-mentioned adhesive composition and then dry it. The adhesive composition may be applied to a release sheet, or it may be applied directly to the surface of the substrate or buffer layer. When applying the adhesive composition to a release sheet to obtain a release sheet with an adhesive layer, the adhesive layer of the release sheet with the adhesive layer can then be attached to the surface of the substrate or buffer layer. The method for applying the adhesive composition will be described in the same manner as the method for applying the thermosetting resin composition described above.

[0098] <Uses of adhesive sheets> Examples of workpiece processing performed with the adhesive sheet attached in this embodiment include back grinding, where the other side of the workpiece is ground while the adhesive sheet is attached to one side; dicing, where the workpiece is divided into individual pieces while the adhesive sheet is attached to one side; workpiece transport; and picking up the individual pieces of the workpiece. Among these, the adhesive sheet of this embodiment is suitable for grinding workpieces, is more suitable for back grinding workpieces, and is even more suitable for back grinding in which the back surface of a workpiece is ground with the adhesive sheet of this embodiment attached to the circuit-forming surface of the workpiece. In particular, the adhesive sheet of this embodiment has the effect of suppressing the occurrence of cracks when thinning a workpiece, and is therefore suitable for processes such as pre-dicing and stealth pre-dicing. Specifically, it is suitable for use in processes in which a workpiece has grooves on its surface or a modified region inside, and the workpiece is affixed to the surface of the workpiece and the back surface of the workpiece is ground, thereby dividing the workpiece into multiple individual workpiece pieces starting from the grooves or the modified region.

[0099] [Manufacturing method for electronic devices] The method for manufacturing the electronic device of this embodiment is: The adhesive sheet for workpiece processing of this embodiment is applied to the surface of a workpiece with the adhesive layer as the application surface, The process involves grinding the back surface of the workpiece while the adhesive sheet for workpiece processing attached to the workpiece is fixed in place. This is a method for manufacturing an electronic device, including [the specified element].

[0100] Furthermore, the method for manufacturing the electronic device of this embodiment is A division line formation step, which is a step of forming grooves on the surface of the workpiece, or a step of forming a modified region from the surface or back surface of the workpiece into the interior of the workpiece, After step a, or before or after step b, a sheet application step is performed in which the adhesive sheet for workpiece processing of this embodiment is applied to the surface of the workpiece with the adhesive layer as the application surface. Grinding and fragmentation step, in which, with the adhesive sheet for workpiece processing attached to the workpiece fixed, the back surface of the workpiece is ground to fragment the workpiece into a plurality of workpiece fragments starting from the groove or the modified region, Preferably, the method is a method for manufacturing an electronic device, which includes [the specified element]. Furthermore, the manufacturing method of the electronic device according to this embodiment may include a peeling step, after the grinding and individualization steps, in which the adhesive sheet for workpiece processing according to this embodiment is peeled off from a plurality of workpieces. Furthermore, the manufacturing method of an electronic device having step a above corresponds to a pre-dicing method, and the manufacturing method of an electronic device having step b above corresponds to a stealth pre-dicing method. The following describes in detail each step of the manufacturing method for the electronic device according to this embodiment.

[0101] <Process for forming planned division lines> The division line formation process consists of either step a, forming grooves on the surface of the workpiece, or step b, forming a modified region from the surface or back of the workpiece into the interior of the workpiece.

[0102] Step a is the process of forming grooves on the surface of the workpiece, and is performed before the adhesive sheet is attached to the surface of the workpiece. The grooves formed on the surface of the workpiece in step a are shallower than the thickness of the workpiece. After step a, the workpiece is back-ground until it reaches the grooves formed in step a, and is divided into multiple individual workpiece pieces. Therefore, in step a, the grooves are formed along the dividing lines that occur when the workpiece is divided into individual pieces. Groove formation can be performed by dicing using conventionally known wafer dicing equipment, etc.

[0103] Step b is a step of forming a modified region inside the workpiece from the surface or back surface of the workpiece, and may be performed before or after attaching the adhesive sheet to the surface of the workpiece. In step b, the modified region is formed inside the workpiece by irradiating it with a laser focused on the workpiece's interior. This modified region is a brittle part of the workpiece that is broken down by back grinding, or by the force applied during grinding, and serves as the starting point for the workpiece to be fragmented. Therefore, the modified region is formed along the dividing line when the workpiece is divided and fragmented. The laser irradiation may be performed from either the front or back side of the workpiece. If step b is performed after the sheet application process, the laser may be irradiated onto the workpiece via the adhesive sheet.

[0104] <Sheet application process> The sheet application process is a process in which an adhesive sheet is applied to the surface of a workpiece, with the adhesive layer facing the application surface, after process a, or before or after process b. The method of attaching the adhesive sheet is not particularly limited; for example, conventionally known methods such as using a laminator can be applied.

[0105] <Grinding and framing process> The grinding and fragmentation process involves grinding the back surface of the workpiece while the adhesive sheet for workpiece processing attached to the workpiece is fixed by a support device, thereby fragmenting the workpiece into multiple fragments starting from the grooves or modified regions. A workpiece to which an adhesive sheet has been attached and to which grooves or modified regions have been formed is fixed by a support device on the adhesive sheet side. The support device is not particularly limited, but a device that sucks and holds the object to be fixed, such as a chuck table, is preferred.

[0106] Next, the back surface of the fixed workpiece is ground to break down the workpiece into multiple individual pieces. In back grinding, if a groove has been formed in the workpiece by step a, the workpiece is ground to a point where the grinding surface reaches at least the bottom of the groove. Through this back grinding, the groove becomes a cut that penetrates the workpiece, and the workpiece is divided by the cut into individual workpiece fragments. On the other hand, if a modified region is formed in the workpiece by process b, the grinding surface may reach the modified region, but it does not have to reach the modified region strictly. That is, grinding should be done up to a position close to the modified region so that the workpiece is broken down into individual pieces starting from the modified region. For example, after grinding up to a position close to the modified region without breaking the workpiece into individual pieces, a pickup tape may be attached to the workpiece and the workpiece may be broken into individual pieces by stretching the pickup tape.

[0107] The shape of the individualized workpiece pieces may be rectangular, or it may be an elongated shape such as a rectangle. The thickness of the individualized workpiece fragments is not particularly limited, but is preferably 5 to 100 μm, more preferably 7 to 70 μm, and even more preferably 10 to 45 μm. The size of the individualized workpiece pieces is not particularly limited, but is preferably 50 mm. 2 Less than, more preferably 30 mm 2 Less than 10 mm, more preferably 10 mm 2 It is less than.

[0108] <Peeling process> The peeling process is a step in which the adhesive sheet is peeled off from multiple pieced workpieces after the grinding and piece-forming processes. When the adhesive layer of an adhesive sheet is formed from an energy-ray curable adhesive, the adhesive is cured by irradiating it with energy rays to reduce the peeling force of the adhesive layer before the adhesive sheet is peeled off. Furthermore, when peeling off the adhesive sheet, a pickup tape may be used. The pickup tape is, for example, composed of an adhesive sheet having a base material and an adhesive layer provided on one side of the base material. When using pickup tape, first, the pickup tape is attached to the back side of the individualized workpiece pieces, and their position and orientation are adjusted so that they can be picked up. At this time, it is preferable to also attach the ring frame, which is positioned on the outer circumference of the individualized workpiece pieces, to the pickup tape, and fix the outer edge of the pickup tape to the ring frame. Next, the adhesive sheet is peeled off from the multiple individualized workpiece pieces fixed on the pickup tape. Subsequently, multiple workpiece fragments on the pickup tape may be picked up and then fixed onto a substrate or the like to manufacture an electronic device. [Examples]

[0109] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. In the following explanation, all mentions of the amount of each ingredient refer to the amount of the active ingredient. The methods for measuring and evaluating various physical properties are as follows:

[0110] [Mass-average molecular weight (Mw) and number-average molecular weight (Mn)] The mass-average molecular weight (Mw) and number-average molecular weight (Mn) were measured using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8220") under the following conditions and determined on a standard polystyrene basis. (Measurement conditions) • Columns: "TSK guard column HXL-H", "TSK gel GMHXL (x2)", "TSK gel G2000HXL" (all manufactured by Tosoh Corporation) Column temperature: 40°C • Developing solvent: tetrahydrofuran ·Flow rate: 1.0mL / min

[0111] [Thickness measurement of adhesive sheets, etc., for workpiece processing] The total thickness of the adhesive sheet used for workpiece processing, the thickness of each layer, and the thickness of the test pieces made from these were measured using a constant-pressure thickness measuring instrument (manufactured by Teclock Co., Ltd., product name "PG-02"). Ten arbitrary points were measured, and the average value was calculated. The total thickness of the adhesive sheet for workpiece processing is calculated by measuring the thickness of the adhesive sheet with the release liner attached and subtracting the thickness of the release liner from that thickness. Furthermore, the thickness of the buffer layer is the value obtained by subtracting the thickness of the base material from the thickness of the base material with the buffer layer attached. Furthermore, the thickness of the adhesive layer is the total thickness of the adhesive sheet for workpiece processing minus the thickness of the buffer layer and the base material.

[0112] [Evaluation of low odor] The release sheets were peeled off from the adhesive workpiece processing sheets with release sheets manufactured in the examples and comparative examples, and the odor was evaluated sensorily at room temperature (23°C). The low odor properties of the adhesive workpiece processing sheets were evaluated based on the following criteria. A: No odor C: Odor present

[0113] [Measurement of surface resistivity of buffer layer] (1) Preparation of substrate with buffer layer (1-1) Method for preparing a substrate with a buffer layer using a thermosetting buffer layer forming composition A polyethylene terephthalate (PET) film with a thickness of 50 μm was prepared as a substrate. A thermosetting resin composition, prepared in Examples 1-8 and Comparative Examples 1-3 as a buffer layer forming composition, was applied to one surface of the substrate to form a coating film with a drying thickness of 30 μm. The coating film was then heated at 110°C for 2 minutes to dry the organic solvent and allow the thermosetting reaction of the thermosetting resin composition to proceed, thereby obtaining a substrate with a buffer layer with a thickness of 30 μm formed on one surface of the substrate. (1-2) Method for preparing a substrate with a buffer layer using an energy ray curable buffer layer forming composition A buffered substrate was obtained by the same method as described in Comparative Example 4, which will be described later, in which a buffered layer with a thickness of 28 μm was formed on one surface of the substrate. (2) Measurement of surface resistivity The buffer-coated substrate obtained above was cut into 10cm x 10cm pieces, and the surface resistivity of the buffer layer was measured in accordance with JIS K 6911:1995 using the double-ring electrode method (two-terminal method). The measuring equipment used was the resistance meter (digital electrometer) "R8252" manufactured by ADC Corporation and the sample chamber "TR42" manufactured by Advantest Corporation. The measurements were performed in an environment of 23°C and 50% RH, and the surface resistivity was calculated based on the current value when a voltage of 100V was applied for 1 minute. Each buffer-coated substrate was measured four times, and the arithmetic mean of the four measured values ​​was taken as the surface resistivity of the buffer layer.

[0114] [Measurement of delamination voltage] Under conditions of 23°C and 50% RH (relative humidity), the adhesive sheets for workpiece processing with release sheets prepared in the examples and comparative examples were attached to the surface of a silicon wafer (mirror finish, 8 inches in diameter) using a backgrind tape laminator (Lintec Corporation, product name "RAD-3510", table temperature: 23°C) while peeling off the release sheets, and left to stand for 30 minutes under the same conditions. Under the same conditions, the adhesive sheets for workpiece processing were peeled off from the silicon wafer using the tape peeling mechanism of a wafer mounter (Lintec Corporation, product name "RAD-2700F / 12") at a peeling speed of 600 mm / min and a table temperature of 40°C. The voltage (maximum voltage during peeling) was measured at a point 10 mm perpendicular to the silicon wafer surface from the peeling point of the adhesive layer on the silicon wafer surface using a peeling electrostatic charge meter (Prostat, product name "PFM-711A"). No electrostatic discharge devices such as ionizers were used when measuring the peeling voltage. Similar measurements were performed on five silicon wafers for each adhesive sheet used for workpiece processing, and the arithmetic mean of the five measured values ​​was defined as the peeling band voltage. Samples with a peeling band voltage of 500V or less were judged to be good.

[0115] [Evaluation of grindability: Back grinding] A silicon wafer with a diameter of 12 inches and a thickness of 775 μm was coated with the adhesive sheets for workpiece processing prepared in the examples and comparative examples, with the adhesive layer facing the bonding surface, using a back-grinding tape laminator (Lintec Corporation, product name "RAD3510F / 12"). Next, the silicon wafer was ground (including dry polishing) using a back-grinding machine (Disco Corporation, product name "DGP8761") with the adhesive sheets for workpiece processing fixed in place, until its thickness reached 30 μm. The appearance of the silicon wafer after grinding was visually observed, and the grindability in back-grinding was evaluated based on the following criteria. A: No damage was found in the silicon wafer. C: Damage was detected in the silicon wafer.

[0116] [Evaluation of grindability: Stealth tip dicing process] A silicon wafer with a diameter of 12 inches and a thickness of 775 μm was coated with the adhesive sheets for workpiece processing prepared in the examples and comparative examples, with the adhesive layer facing the bonding surface, using a backgrind tape laminator (Lintec Corporation, product name "RAD3510F / 12"). Subsequently, a laser saw (Disco Corporation, product name "DFL7361") was used to form a grid-like modified region inside the silicon wafer. The grid size was 10 mm x 10 mm. Next, using a back grinding machine (Disco Corporation, product name "DGP8761"), the silicon wafer was ground (including dry polishing) until its thickness reached 30 μm, and the silicon wafer was divided into multiple chips starting from the modified region. After that, the adhesive sheet for workpiece processing was irradiated with energy rays (ultraviolet light). Subsequently, dicing tape (Lintec Corporation, product name "Adwill D-175D") was attached to the side of the multiple chips opposite to the side where the adhesive sheet for workpiece processing was attached, and the adhesive sheet for workpiece processing was peeled off from the multiple chips. Multiple chips were observed using a digital microscope after the adhesive sheet for workpiece processing was removed. They were classified according to the following criteria based on crack size, and the number of chips with cracks was counted. Grindability in stealth tip dicing was then evaluated based on the following criteria. The crack size (μm) was determined by comparing the length of the crack along the longitudinal direction of the chip (μm) with the length of the crack along the transverse direction of the chip (μm), and the larger value was used. (Classification of cracks by crack size) Large cracks: Cracks with a size exceeding 20 μm Medium cracks: Cracks with a size of 10 μm or more and 20 μm or less. Small cracks: Cracks with a size of less than 10 μm (Evaluation Criteria) A: No large cracks, no more than 7 medium cracks, and no more than 15 small cracks. B: There are 0 large cracks, 8 to 10 medium cracks, and 15 or fewer small cracks, or there are 0 large cracks, 7 or fewer medium cracks, and 16 to 20 or fewer small cracks. C: One or more large cracks, or 11 or more medium cracks, or 21 or more small cracks.

[0117] [Manufacturing of adhesive compositions] Manufacturing Example 1 An acrylic polymer was obtained by copolymerizing 50 parts by mass of n-butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 30 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 polymer (Mw: 500,000). To 100 parts by mass of this energy-ray curable acrylic polymer, 10 parts by mass of a polyfunctional urethane acrylate-based UV-curable compound (manufactured by Mitsubishi Chemical Corporation, product name "Shiko UT-4332") as an energy-ray curable compound, 0.38 parts by mass of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "Takenate D-101E") based on solid content, 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 agent for an adhesive composition with a solid content of 34% by mass. The adhesive composition obtained in Production Example 1 is referred to as "Composition 1" in Table 1.

[0118] Manufacturing Example 2 An acrylic polymer was obtained by copolymerizing 80 parts by mass of 2-ethylhexyl acrylate (2EHA) and 20 parts by mass of 2-hydroxyethyl acrylate (2HEA). 2-methacryloyloxyethyl isocyanate (MOI) was reacted with this polymer to add 2-methacryloyloxyethyl isocyanate to 80 mol% of the total hydroxyl groups of the acrylic polymer, thereby obtaining an energy-ray curable acrylic polymer (Mw: 500,000). To 100 parts by mass of this energy-ray curable acrylic polymer, 0.38 parts by mass (based on solid content) of an isocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "Takenate D-101E") 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 an adhesive composition with a solid content of 30% by mass. The adhesive composition obtained in Production Example 2 is referred to as "Composition 2" in Table 1.

[0119] [Manufacturing of adhesive sheets for workpiece processing] Examples 1-8 (1) Preparation of substrate with buffer layer The following raw materials were prepared as raw materials for the buffer layer forming composition. <Thermosetting resin> Polyester urethane resin having two or more hydroxyl groups (manufactured by Toyobo Co., Ltd., product name "UR-1400", glass transition temperature 83°C, number average molecular weight (Mn) 40,000, hydroxyl value 2-3 KOH mg / g, diluted with solvent (solvent containing 50% by mass of methyl ethyl ketone and 50% by mass of toluene), solid content concentration 30% by mass) <Crosslinking agent> Isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate HL", diluted with ethyl acetate, solid content concentration 74-76% by mass) <Curing catalyst> Dibutyltin dilaurate (manufactured by Toyo Chem Co., Ltd., product name "BXX3778G") <Antistatic agent> Ionic material 1: Reaction product of alkanolamine and dialkyl succinate sulfonic acid, manufactured by Nippon Emulsifier Co., Ltd., product name "Aminoion AS400" Ionic material 2: Manufactured by Nippon Carlit Co., Ltd., product name "CIL-H11"

[0120] A thermosetting resin composition for forming a buffer layer was prepared by blending 100 parts by mass of the above-mentioned thermosetting resin, 7.5 parts by mass of a crosslinking agent, 0.5 parts by mass of a curing catalyst, and the type and amount of antistatic agent shown in Table 1.

[0121] Next, a polyethylene terephthalate (PET) film having the thickness shown in Table 1 was prepared as a substrate, and the thermosetting resin composition obtained above was applied to one surface of the substrate to form a coating film. The amount of thermosetting resin composition applied was adjusted so that the thickness of the formed buffer layer was the thickness shown in Table 1. Then, the coating film was heated at 110°C for 2 minutes to dry the organic solvent and allow the thermosetting reaction of the thermosetting resin composition to proceed, thereby obtaining a substrate with a buffer layer having the thickness shown in Table 1 formed on one surface of the substrate.

[0122] (2) Formation of the adhesive layer Next, adhesive compositions of the types shown in Table 1 were applied to the release surface of a release sheet (Lintec Corporation, product name "SP-PET381031") so that the thickness after drying was as shown in Table 1, and then heated and dried to produce a release sheet with an adhesive layer.

[0123] Next, the adhesive layer of the release sheet with an adhesive layer was bonded to the surface of the base material with the buffer layer that was opposite to the buffer layer, thereby obtaining an adhesive sheet for workpiece processing with a release sheet, having the buffer layer, base material, adhesive layer, and release sheet in this order.

[0124] Comparative Example 1 An adhesive sheet for workpiece processing with a release sheet was obtained in the same manner as in Example 1, except that an antistatic agent was not incorporated into the buffer layer forming composition.

[0125] Comparative Example 2 In Example 7, an adhesive sheet for workpiece processing with a release sheet was obtained in the same manner as in Example 7, except that an antistatic agent was not incorporated into the buffer layer forming composition.

[0126] Comparative Example 3 An adhesive sheet for workpiece processing with a release sheet was obtained in the same manner as in Example 8, except that an antistatic agent was not incorporated into the buffer layer forming composition.

[0127] Comparative Example 4 (1) Preparation of buffer layer forming composition An energy-ray curable resin composition for forming a buffer layer was prepared by blending 50 parts by mass of a urethane acrylate oligomer (manufactured by Sartomer, trade name "CN8881"), 50 parts by mass of polyethylene glycol (400) diacrylate as an energy-ray curable compound, and 2.0 parts by mass of 2-hydroxy-2-methyl-1-phenyl-propan-1-one (manufactured by IGM Resins, trade name "Omnirad 1173") as a photopolymerization initiator. (2) Preparation of adhesive sheets The energy-curable resin composition obtained above was applied to the release surface of a release sheet (Lintec Corporation, product name "SP-PET381031") to form a coating film. Next, the coating film was partially cured by irradiating it with ultraviolet light, thereby forming a 28 μm thick layer of partially cured energy-curable resin composition on the release sheet. The above ultraviolet irradiation was carried out using a belt conveyor type ultraviolet irradiation device (manufactured by iGraphix, product name "ECS-401GX") and a high-pressure mercury lamp (manufactured by iGraphix, product name "H04-L41"), with a lamp height of 260 mm, output of 80 W / cm, and illuminance of 70 mW / cm. 2 , irradiation amount 30mW / cm 2 The procedure was performed under the following irradiation conditions. Next, the surface of the semi-cured layer of the energy-ray curable resin composition formed on the release sheet was bonded to one side of a PET film (manufactured by Mitsubishi Plastics, Inc., product name "PET50 T910 WM19", thickness 50 μm) used as a substrate. Subsequently, the energy-ray curable resin composition was completely cured by irradiating it with ultraviolet light from the release sheet side, obtaining a substrate with a buffer layer, in which a buffer layer with a thickness of 28 μm was formed on one side of the substrate. The above ultraviolet irradiation was performed using the aforementioned ultraviolet irradiation device and high-pressure mercury lamp, with a lamp height of 210 mm, a lamp output of 120 W / cm, and an illuminance of 155 mW / cm. 2 , irradiation amount 600mW / cm 2 The procedure was performed under the following irradiation conditions. Next, the adhesive layer of a release sheet with an adhesive layer, prepared in the same manner as in Example 1, was bonded to the surface of the buffer-layered substrate opposite to the buffer layer, thereby obtaining a release sheet adhesive sheet for workpiece processing having a buffer layer, substrate, adhesive layer, and release sheet in this order.

[0128] Table 1 shows the evaluation results of the adhesive sheets for workpiece processing obtained in each example and comparative example.

[0129] [Table 1]

[0130] Table 1 shows that the adhesive sheets for workpiece processing in Examples 1 to 8 of this embodiment have sufficiently suppressed peeling voltage, low odor, and excellent abrasive properties. On the other hand, the adhesive sheets for workpiece processing in Comparative Examples 1 to 3, in which the buffer layer did not contain an antistatic agent, did not have sufficiently suppressed peeling voltage. Furthermore, the adhesive sheet for workpiece processing in Comparative Example 4, in which the buffer layer was formed using an energy ray curable resin composition, was inferior in terms of low odor.

Claims

1. It has a buffer layer, a base material, and an adhesive layer, The adhesive layer is present on one surface, The buffer layer is a layer containing a cured product of a thermosetting resin composition, The thermosetting resin composition contains an antistatic agent. Adhesive sheet for workpiece processing.

2. The adhesive sheet for workpiece processing according to claim 1, wherein the antistatic agent is an ionic material.

3. The surface resistivity of the buffer layer is 1.0 × 10 １２ An adhesive sheet for workpiece processing according to claim 1 or 2, wherein the density is less than or equal to Ω / sq.

4. The adhesive sheet for workpiece processing according to claim 1 or 2, wherein the thickness of the buffer layer is 2 to 100 μm.

5. The adhesive sheet for workpiece processing according to claim 1 or 2, wherein the thermosetting resin composition contains a polyester resin.

6. The adhesive sheet for workpiece processing according to claim 5, wherein the polyester resin is a polyester urethane resin.

7. The adhesive sheet for workpiece processing according to claim 5, wherein the polyester resin is a polyester resin having two or more hydroxyl groups, and the thermosetting resin composition further contains a polyvalent isocyanate compound.

8. The adhesive sheet for workpiece processing according to claim 1 or 2, wherein the buffer layer is located on one side of the base material and the adhesive layer is located on the other side of the base material.

9. An adhesive sheet for workpiece processing according to claim 1 or 2, used for grinding a workpiece.

10. The workpiece has grooves on its surface or has a modified region inside, The adhesive sheet for workpiece processing according to claim 1 or 2, used to fragment a workpiece into a plurality of workpiece fragments starting from the groove or the modified region, by grinding the back surface of the workpiece while the adhesive sheet for workpiece processing attached to the surface of the workpiece is fixed in place.

11. A method for manufacturing an adhesive sheet for workpiece processing according to claim 1 or 2, A method for manufacturing an adhesive sheet for workpiece processing, comprising the step of curing the thermosetting resin composition by heating it.

12. A step of attaching the adhesive sheet for workpiece processing described in claim 1 or 2 to the surface of a workpiece with the adhesive layer as the attachment surface, The process involves grinding the back surface of the workpiece while the adhesive sheet for workpiece processing attached to the workpiece is fixed in place. A method for manufacturing an electronic device, including

13. A division line formation step, which is a step of forming grooves on the surface of the workpiece, or a step of forming a modified region from the surface or back surface of the workpiece into the interior of the workpiece, A sheet application step is performed, after step a, or before or after step b, by applying the adhesive sheet for workpiece processing described in claim 1 or 2 to the surface of the workpiece with the adhesive layer as the application surface. A grinding and fragmentation step is performed, in which, with the adhesive sheet for workpiece processing attached to the workpiece fixed in place, the back surface of the workpiece is ground to fragment the workpiece into a plurality of workpiece fragments starting from the groove or the modified region. A method for manufacturing an electronic device, including

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