TW201842106A - Adhesive sheet - Google Patents

Abstract

A method for peeling off an adhesive sheet is a method of peeling off an adhesive sheet 1 having at least an adhesive layer 2 and an adhesive sheet 1 which is adhered to an adhesive surface W and W' adhered to an adhesive surface 2 of an adhesive layer 2, The adhesive layer 2 has a concave portion 3 on the adhesive surface P, and the adherends W and W' are adhered to the adhesive sheet 1 in such a manner that a separate space C is formed by the concave portion 3 of the adhesive layer 2. The pressure-sensitive adhesive sheet 1 to which at least the adherends W and W' are adhered is subjected to a pressure reduction treatment for expanding the gas in the space C, so that the adhesion of the adhesive layer 2 is lowered to bond the adhesive sheet 1 and the adherends W and W'. Stripped. When using this method, the adhesion can be reduced at the required timing by a novel mechanism of action.

Description

Adhesive film

The present invention relates to an adhesive sheet which is capable of lowering the adhesive force at a desired timing and which is easily peeled off by the adherend.

In the manufacturing steps of a semiconductor wafer, a display device, or the like, an adhesive sheet is used to temporarily fix an electronic component such as a semiconductor wafer or a display device constituent member (electronic member/optical member). Such an adhesive sheet can reduce the adhesive force of the adhesive sheet at a desired timing by applying energy or the like, whereby the object to be processed (adhered matter) becomes easily peeled off. In the above-described manufacturing steps, for example, a desired processing step is performed in a state where an adherend of an electronic member, an optical member, or the like is fixed to the adhesive sheet.

As a method for lowering the adhesive force of such an adhesive sheet, there has been proposed a method of forming an adhesive layer using an active energy ray-curable adhesive, and hardening the adhesive layer by irradiating an active energy ray to lower the adhesive force ( For example, Patent Document 1); and a method in which the adhesive layer contains heat-expandable particles, and the heat-expandable particles are expanded by heating to lower the adhesive strength of the adhesive layer (see, for example, Patent Document 2). Prior Technical Literature Patent Literature

[Patent Document 1] Japanese Laid-Open Patent Publication No. Hei No. 8-188757 (Patent Document 2) Japanese Laid-Open Patent Publication No. 2000-248240

Problem to be solved by the invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for peeling off an adhesive sheet and an adherend which can reduce adhesion at a desired timing by a novel mechanism of action. Means to solve the problem

According to a first aspect of the present invention, there is provided a method for peeling an adhesive sheet, wherein a method of peeling an adhesive sheet having at least an adhesive layer and an adhesive sheet which is adhered to an adhesive surface adhered to an adhesive surface of the adhesive layer is characterized in that The adhesive layer has a concave portion on the adhesive surface, and the adhesive is adhered to the adhesive sheet so as to form an independent space by the concave portion of the adhesive layer, and is adhered to at least the adhesive layer. The pressure-sensitive adhesive sheet of the object is subjected to a pressure reduction treatment for expanding the gas in the space to reduce the adhesion of the pressure-sensitive adhesive layer, thereby peeling off the pressure-sensitive adhesive sheet from the adherend (Invention 1).

Moreover, the "slice" of the present invention is also intended to include the concept of "tape".

When the adhesive sheet and the method for peeling the adherend of the present invention are used, the novel action mechanism for expanding the gas in the space by the pressure reduction treatment can lower the adhesive force at the required timing and make the adhesive sheet and the adhesive sheet Peeling of the adherend becomes easy.

In the above invention (Invention 1), the pressure reduction treatment is preferably performed at a lower environmental pressure than in an environment in which the adhesive sheet is attached to the adherend (Invention 2).

In the above invention (Inventions 1 and 2), the adhesive composition for forming the pressure-sensitive adhesive layer may be one which does not have active energy ray hardenability and thermosetting property (Invention 3), and the invention (Invention 3) Wherein the aforementioned adhesive composition is preferably a (meth) acrylate polymer (Invention 4).

In the above invention (Inventions 1 and 2), the adhesive composition forming the above-mentioned adhesive layer may have active energy ray hardening property or thermosetting property (Invention 5), wherein the aforementioned activity (Invention 5) The energy ray-curable adhesive composition preferably contains a (meth) acrylate polymer having an active energy ray-curable group in a side chain (Invention 6).

In the above invention (Inventions 5 and 6), after the adhesive layer is irradiated with an energy ray to cure the adhesive layer, the pressure reduction treatment may be performed (Invention 7), or after the pressure reduction treatment, The above adhesive layer is irradiated with an energy ray to harden the aforementioned adhesive layer (Invention 8).

In the above invention (Inventions 1 to 8), it is preferable that the adhesive sheet is temporarily fixed to the above-mentioned adherend (Invention 9), and in the invention (Invention 9), the above-mentioned adherend may be an electron. Member or optical member (Invention 10).

According to a second aspect of the present invention, there is provided a method of producing a workpiece, wherein the workpiece is processed to obtain a processed product, the method comprising the steps of: providing a workpiece and an adhesive surface having at least an adhesive layer on the adhesive layer; An adhesive sheet having a concave portion, a pasting step of adhering the concave portion of the adhesive surface to the workpiece to form a separate space; a processing step of processing the workpiece adhered to the adhesive sheet into a processed object; and performing The pressure-sensitive adhesive sheet having at least the above-mentioned processed material is placed in a reduced pressure environment to expand the gas in the space, and the adhesive force of the adhesive layer is lowered, and the processed product is peeled off from the adhesive sheet. Step (Invention 11). Effect of the invention

When the adhesive sheet of the present invention and the method of peeling the adherend are used, the adhesive force can be lowered at a desired timing by a novel action mechanism, and peeling of the adhesive sheet and the adherend can be facilitated.

Form for implementing the invention

Hereinafter, embodiments of the present invention will be described. The method of peeling the adhesive sheet of the present embodiment is a method of peeling off the adhesive sheet having at least the adhesive layer and the adherend adhered to the adhesive surface of the adhesive layer. The adhesive layer has a concave portion on the adhesive surface, and the adhesive and the adhesive sheet are adhered to each other in such a manner as to create a separate space by the concave portion of the adhesive layer. In the present embodiment, the adhesive sheet in which the adherend is adhered at least is subjected to a pressure reduction treatment for expanding the gas in the space generated by the concave portion and the adherend, whereby the adhesive force of the adhesive layer is lowered and the adhesive force is lowered. It is easy to peel off the adhesive sheet and the adherend.

[Adhesive sheet] Fig. 1 is a cross-sectional view showing an adhesive sheet used in an embodiment of the present invention. The adhesive sheet 1 of the present embodiment is configured to include the adhesive layer 2, and the adhesive layer 2 has a concave portion 3 on the adhesive surface P, that is, the surface (the surface on the upper side in the first drawing) that is in contact with the adherend. Further, the adhesive sheet 1 of the present embodiment may further include a substrate 4 on a surface (the surface on the lower side in the first drawing) of the adhesive layer opposite to the adhesive surface P. The adhesive sheet 1 of the present embodiment can be used, for example, to temporarily fix an electronic component, an optical member, or the like. Hereinafter, a description will be given focusing on a case where the semiconductor wafer is temporarily fixed.

(1) Adhesive layer The adhesive layer may be an adhesive formed of an adhesive composition which does not have active energy ray hardenability and thermosetting property (hereinafter, referred to as "non-hardening property" in the present specification). The layer may also be an adhesive layer formed of an active energy ray-curable or thermosetting adhesive composition. Further, when the pressure-sensitive adhesive layer is composed of a plurality of layers, it may be a combination of a non-curable pressure-sensitive adhesive layer and a curable pressure-sensitive adhesive layer.

(1-1) Non-curable adhesive composition As the non-curable adhesive composition, for example, an acrylic adhesive composition, a rubber-based adhesive composition, a polyoxygen-based adhesive composition, and a uric acid The ethyl ester-based pressure-sensitive adhesive composition, the polyester-based pressure-sensitive adhesive composition, the polyvinyl ether-based pressure-sensitive adhesive composition, and the like are particularly preferably an acrylic pressure-sensitive adhesive composition. As the acrylic pressure-sensitive adhesive composition, a conventionally known (meth) acrylate polymer-containing material can be used. Moreover, the "polymer" in the present specification is a concept that also includes the concept of "copolymer".

The (meth) acrylate polymer (A) contained in the acrylic pressure-sensitive adhesive composition may be a homopolymer formed of one type of (meth) acrylate monomer, or may be plural The copolymer formed of the (meth) acrylate monomer may be formed of a monomer other than the (meth) acrylate monomer and the (meth) acrylate monomer of one type or plural types. Copolymer. Further, the (meth) acrylate polymer (A) may be used alone or in combination of two or more. The specific type of the compound of the (meth) acrylate monomer is not particularly limited, and specific examples thereof include (meth)acrylic acid, (meth) acrylate, and derivatives thereof (acrylonitrile, itaconic acid, and the like). Further, when specific examples are disclosed for (meth) acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate may be mentioned. (meth) acrylate having a chain skeleton such as 2-ethylhexyl methacrylate; cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isodecyl (meth) acrylate, ( a (meth) acrylate having a cyclic skeleton such as dicyclopentanyl (meth) acrylate, yttrium imide (meth) acrylate or (meth) acryl hydrazino morpholine; 2-hydroxy ethane (meth) acrylate (meth) acrylate having a hydroxyl group such as ester, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; epoxy propyl ( (Meth) acrylate having a reactive functional group other than a hydroxyl group such as methyl acrylate or N-methylaminoethyl (meth) acrylate. In addition, examples of the monomer other than the (meth) acrylate monomer include an olefin such as ethylene or norbornene, vinyl acetate, and styrene. Further, when the (meth) acrylate monomer is an alkyl (meth) acrylate, the alkyl group preferably has a carbon number of from 1 to 18. Further, in the present specification, the term "(meth)acrylic acid" means both of acrylic acid and methacrylic acid. The same is true for other similar terms.

When the adhesive composition forming the pressure-sensitive adhesive layer of the present embodiment contains a crosslinking agent to be described later, the (meth) acrylate polymer (A) may directly contain an adhesive composition, or at least a part thereof may be crosslinked. After the crosslinking reaction is carried out, the agent is contained as a crosslinked product. At this time, the (meth) acrylate polymer (A) is preferably a reactive functional group having a reaction with a crosslinking agent. The type of the reactive functional group is not particularly limited, and may be appropriately determined depending on the type of the crosslinking agent or the like.

For example, when the crosslinking agent is a polyisocyanate compound, the reactive functional group of the (meth) acrylate polymer (A) may, for example, be a hydroxyl group, a carboxyl group, an amine group or the like, and particularly a reactivity with an isocyanate group. Higher hydroxyl groups are preferred. When the crosslinking agent is an epoxy compound, the reactive functional group of the (meth) acrylate polymer (A) may, for example, be a carboxyl group, an amine group or a guanamine group, and particularly an epoxy group. The carboxyl group having a higher reactivity is preferred.

The method of introducing the reactive functional group into the (meth) acrylate polymer (A) is not particularly limited, and as an example, a (meth) acrylate polymer is formed by using a monomer having a reactive functional group. (A) A method of including a structural unit of a monomer having a reactive functional group in a skeleton of a polymer. For example, when a carboxyl group is introduced into the (meth) acrylate polymer (A), a monomer having a carboxyl group such as (meth)acrylic acid may be used to form the (meth) acrylate polymer (A).

When the (meth) acrylate polymer (A) has a reactive functional group, the mass of the structural portion derived from the monomer having a reactive functional group is from the viewpoint of a good degree of crosslinking. The ratio of the total mass of the methyl acrylate polymer (A) is preferably from 1 to 20% by mass, preferably from 2 to 10% by mass.

The weight average molecular weight (Mw) of the (meth) acrylate polymer (A) is preferably from 10,000 to 2,000,000, and preferably from 100,000 to 1,500,000, from the viewpoint of film forming properties at the time of coating. Further, in the present specification, the weight average molecular weight of the (meth) acrylate polymer (A) and the (meth) acrylate polymers (B1) and (B3) described later is gel permeation chromatography (GPC). The value of the standard polystyrene conversion measured by the method, the details of the measurement method are disclosed in the examples described later. Further, the glass transition temperature Tg of the (meth) acrylate polymer (A) is preferably in the range of -70 ° C to 30 ° C, more preferably -60 ° C to 20 ° C. The glass transition temperature can be calculated according to the Fox equation.

(1-2) Active energy ray-curable adhesive composition Active energy ray-curable adhesive composition containing an active energy ray-curable compound (B2) and an active energy ray-curable group introduced into a side chain ( At least one of the methyl acrylate polymers (B3) is preferred. Here, the active energy ray-curable adhesive composition may contain an active energy ray-curable compound (B2) and a (meth) acrylate polymer (B3) having an active energy ray-curable group introduced into its side chain. It is better to have either side to contain either side. In such a case, the active energy ray-curable adhesive composition may further contain a (meth) acrylate polymer (B1) having no active energy ray curability.

(1-2-1) (meth)acrylate polymer (B1) having no active energy ray-curable property The adhesive composition forming the adhesive layer of the present embodiment contains no active energy ray hardenability ( In the case of the methyl acrylate polymer (B1), the (meth) acrylate polymer (B1) may be directly contained in the adhesive composition, or at least a part thereof may be crosslinked with a crosslinking agent described later. It is included as a cross-linking substance. As the (meth) acrylate polymer (B1), the same as the above-mentioned (meth) acrylate polymer (A) for the non-curable adhesive composition can also be used.

(1-2-2) Active energy ray-curable compound (B2) The active energy ray-curable compound (B2) has an active energy ray-curable group and is polymerized when it is irradiated with an active energy ray such as ultraviolet rays or electron beams. . The active energy ray-curable group of the active energy ray-curable compound (B2), for example, a group containing an active energy ray-curable carbon-carbon double bond, and specifically, a (meth) acrylonitrile group or a vinyl group can be exemplified. Wait.

The active energy ray-curable compound (B2) is not particularly limited as long as it has the above-mentioned active energy ray-curable group, and a low molecular weight compound (monofunctional or polyfunctional monomer) is used from the viewpoint of general versatility. And oligomers) are preferred. Specific examples of the low molecular weight active energy ray-curable compound (B2) include trimethylolpropane tri(meth)acrylate, tetramethylol methane tetra(meth)acrylate, and neopentyl alcohol. Tris(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate or 1,4-butanediol di(meth)acrylate a cyclic aliphatic skeleton such as 1,6-hexanediol di(meth)acrylate, dicyclopentadienyldimethoxydi(meth)acrylate or isodecyl (meth)acrylate ( Methyl) acrylate, polyethylene glycol di(meth) acrylate, (meth) acrylate oligo, urethane (meth) acrylate oligomer, epoxy modified (meth) acrylate An acrylate type compound, such as a polyether (meth) acrylate, can be used individually by 1 type or in combination of 2 or more types.

The active energy ray-curable compound (B2) usually has a molecular weight of from 100 to 30,000, preferably from about 300 to 10,000.

The ratio of the content of the active energy ray-curable compound (B2) of the active energy ray-curable adhesive composition to the content of other components is not particularly limited, and the active energy ray-curable adhesive composition contains an active energy ray-curable compound (B2). And the active energy ray-curable compound (B2) with respect to 100 parts by mass of the (meth) acrylate polymer (B1), in the case of the (meth) acrylate polymer (B1) having no active energy ray curability (B1) It can be used in a ratio of preferably from 10 to 400 parts by mass, more preferably from 30 to 350 parts by mass. Further, when the active energy ray-curable compound (B2) and the (meth) acrylate polymer (B3) having an active energy ray-curable group introduced into the side chain are described later, the (meth) acrylate is added to the (meth) acrylate. The content of the active energy ray-curable compound (B2) in 100 parts by mass of the polymer (B3) is preferably in the above range. Further, the active energy ray-curable adhesive composition contains an active energy ray-curable compound (B2), the above (meth) acrylate polymer (B1), and an active energy ray-curable group (methyl group) introduced into the side chain. In the case of the acrylate polymer (B3), the active energy ray-curable compound (B2) is 100 parts by mass based on the total amount of the (meth) acrylate polymer (B1) and the (meth) acrylate polymer (B3). The content is preferably in the above range.

(1-2-3) (meth)acrylate polymer (B3) in which an active energy ray-curable group is introduced into a side chain. The active energy ray-curable adhesive composition of the present embodiment contains a side chain introduced therein. In the case of the active energy ray-curable group (meth) acrylate polymer (B3), the (meth) acrylate polymer (B3) may be directly contained in the adhesive composition, or at least a part thereof will be described later. The crosslinking agent undergoes a crosslinking reaction and is contained as a crosslinked product.

The main skeleton of the (meth) acrylate polymer (B3) having the active energy ray-curable group introduced into the side chain is not particularly limited, and the same as the above (meth) acrylate polymer (B1) can be exemplified.

The active energy ray-curable group to be introduced into the side chain of the (meth) acrylate polymer (B3) is, for example, a group containing an active energy ray-curable carbon-carbon double bond, and specifically, (meth) can be exemplified. Acryl sulfhydryl and the like. The active energy ray-curable group may also be bonded to the (meth) acrylate polymer (B3) through an alkyl group, an alkoxy group, a polyalkylene group or the like.

The (meth) acrylate polymer (B3) having an active energy ray-curable group introduced into the side chain, for example, can have a functional group such as a hydroxyl group, a carboxyl group, an amine group, a substituted amine group or an epoxy group. An acrylate polymer obtained by reacting a compound having a substituent which reacts with the functional group and a curable group having 1 to 5 active energy ray-curable carbon-carbon double bonds per molecule. Such a (meth) acrylate polymer can be composed of a (meth) acrylate monomer having a functional group such as a hydroxyl group, a carboxyl group, an amine group, a substituted amino group or an epoxy group, or a derivative thereof, and a constituent thereof The monomer of (B1) is obtained by copolymerization. Further, examples of the curable group-containing compound include (meth)acryloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, and (meth)acryl decyl isocyanate. The allyl isocyanate, the epoxy propyl (meth) acrylate, the (meth) acrylic acid, etc. can be used individually by 1 type or in combination of 2 or more types.

In addition, when the adhesive composition of the adhesive layer of the present embodiment contains a crosslinking agent to be described later, the (meth)acrylate polymer (B3) having an active energy ray-curable group is introduced into the side chain to have The reactive functional group for the crosslinking agent reaction is preferred. The type of the reactive functional group is not particularly limited, and the (meth) acrylate polymer (B1) (and the aforementioned (meth) acrylate polymer (A) related to the non-curable adhesive composition can be exemplified. ) the same thing.

The weight average molecular weight (Mw) of the (meth) acrylate polymer (B3) having an active energy ray-curable group introduced into the side chain is preferably from 100,000 to 2,000,000, more preferably from 300,000 to 1,500,000.

Further, the glass transition temperature (Tg) of the (meth) acrylate polymer (B3) is preferably -70 to 30 ° C, preferably -60 to 20 ° C. Further, in the present specification, the glass transition temperature (Tg) of the (meth) acrylate polymer (B3) means the glass transition temperature of the (meth) acrylate polymer before reacting with the curable group-containing compound. (Tg).

(1-3) Thermosetting Adhesive Composition As the thermosetting adhesive composition, an epoxy resin, a phenol resin or the like can be mentioned.

(1-4) Crosslinking agent The adhesive composition for forming the pressure-sensitive adhesive layer of the present embodiment may contain a crosslinking agent capable of reacting with the polymer contained in the above-mentioned adhesive composition. In this case, the adhesive layer of the present embodiment can contain a polymer ((meth)acrylate polymer (A), (B1), (B3), etc.) contained in the adhesive composition. A cross-linking product obtained by crosslinking of the crosslinking agent.

Examples of the type of the crosslinking agent include a polyisine compound such as a polyisocyanate compound, an epoxy compound, a metal chelating compound, and an anthranilyl compound, a melamine resin, a urea resin, a dialdehyde, and a hydroxyl group. A base polymer, a metal alkoxide, a metal salt, or the like can be used alone or in combination of two or more. Among these, an epoxy compound or a polyisocyanate compound is preferable because it is easy to control a crosslinking reaction or the like.

The polyisocyanate compound has a compound having two or more isocyanate groups per molecule. Specific examples thereof include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate and benzodimethyl diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and isophorone diisocyanate. An alicyclic polyisocyanate such as hydrogenated diphenylmethane diisocyanate, and the like, and the biuret or trimer isocyanate are further blended with ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and hydrazine. An adduct of a reactant containing a low molecular weight active hydrogen compound such as sesame oil or the like.

Examples of the epoxy compound include 1,3-bis(N,N'-diepoxypropylaminomethyl)cyclohexane, N,N,N',N'-tetraepoxypropyl group- M-xylylenediamine, ethylene glycol diepoxypropyl ether, 1,6-hexanediol diepoxypropyl ether, trimethylolpropane diepoxypropyl ether, diepoxypropylaniline, Di-epoxypropylamine and the like.

The content of the crosslinking agent of the adhesive composition forming the adhesive layer is relative to the polymer contained in the adhesive composition (for example, (meth) acrylate polymers (A), (B1) and (B3)) 100 parts by mass, preferably 0.01 to 50 parts by mass, preferably 0.02 to 10 parts by mass, 0.03 to 5 parts by mass, more preferably 0.05 to 2 parts by mass, and particularly preferably 0.08 to 0.5 parts by mass. .

When the adhesive composition forming the pressure-sensitive adhesive layer of the present embodiment contains a crosslinking agent, an appropriate crosslinking accelerator may be contained depending on the type of the crosslinking agent or the like.

(1-5) Other components The adhesive composition for forming the pressure-sensitive adhesive layer of the present embodiment may contain, in addition to the above components, a photopolymerization initiator, a photosensitizer, a crosslinking accelerator, a dye, a pigment, and the like. Various additives such as coloring materials, flame retardants, fillers, heat transfer agents, adhesion-imparting agents, plasticizers, antistatic agents, and the like. In particular, when the adhesive composition is active energy ray-curable which is cured by an active energy ray such as ultraviolet rays, the adhesive composition preferably contains a photopolymerization initiator.

Examples of the photopolymerization initiator include a benzoin compound, an acetophenone compound, a mercaptophosphine oxide compound, a titanocene compound, and 9-oxosulfuric acid. (thioxanthone), a photoinitiator such as a peroxide compound, a photosensitizer such as an amine or benzoquinone, and the like, specifically, 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether , benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β- Chloropurine, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, and the like may be used alone or in combination of two or more. When ultraviolet rays are used as the energy ray, the irradiation time and the irradiation amount can be reduced by blending the photopolymerization initiator.

(2) Concave The adhesive layer 2 has a concave portion 3 on the adhesive surface P. As will be described later, in the method of peeling the adhesive sheet of the present embodiment, the adherend is adhered to the adhesive sheet P (adhesive surface P) so as to create a space by the concave portion 3 of the adhesive layer 2.

The adhesive layer 2 preferably has independent recesses 3. Here, the recess 3 is independent, and means that all the outer edges of the recess 3 are surrounded by a flat portion (a case called a non-recessed portion) constituting the adhesive surface P, in other words, the recess 3 is not connected to the adhesive sheet 1. Ends. When the adhesive layer 2 has the independent recessed part 3, it is easy to make the space by the to-be-adhered body and the recessed part 3 of the adhesive agent layer 2 the independent space.

Further, the adhesive layer 2 preferably has a plurality of recesses 3. Since the adhesive layer 2 has a plurality of concave portions 3, it is easy to make the space created by the adherend and the concave portion 3 of the adhesive layer 2 an independent space. Further, the adhesive layer 2 is particularly preferably provided with a plurality of independent recesses 3. Further, when the adhesive layer 2 has a plurality of concave portions, the concave portions 3 are not necessarily all independent, and a part thereof may be connected to the end portion of the adhesive sheet 1.

The shape of the concave portion 3 is not particularly limited. For example, when the plurality of concave portions 3 are provided, the respective concave portions 3 may have the same shape, and each may have a different shape. For example, as shown in FIG. 2, the recessed portion 3 may have a convex polygonal shape (in the form of an ellipse and an oblong shape) (including FIG. 2(a)) and a quadrangular shape when viewed in a plan view of the concave portion 3 of the adhesive surface P. (b)), a concave polygonal shape such as a star shape (the same as (c)), and the like, and the combination of the combinations as a predetermined pattern (same (d), (e)), and may also be an indefinite shape. (same (f)).

Here, in FIG. 2(d), a plurality of rectangular recesses 31 are arranged in parallel with each other in the longitudinal direction to form one repeating unit U, and the longitudinal direction of the rectangular recess 31 constituting the repeating unit U is alternated. In a manner, a plurality of repeating units U are alternately arranged in an alternate manner. Further, in Fig. 2(e), one repeating unit U' is formed by a plurality of rectangular recesses 32 and two right-angled triangular recesses 33, and such repeating units U' are alternately arranged. In the repeating unit U', one side of the right-angled triangular recess 33 is formed to be parallel to the long side of the rectangular recess 32, and the oblique side of the right-angled triangular recess 33 is opposed to the short side of the rectangular recess 32. A rectangular recess 32 and a right-angled triangular recess 33 are disposed. The plurality of rectangular recesses 32 are longer as the long sides are separated from the right-angled triangular recesses 33. In Fig. 2(f), the concave portion 34 has an indefinite shape, and the size (length, width, depth, and the like) of the concave portion 34 is not limited by a specific value. Further, the width and direction of one recess 34 are continuously or intermittently changed and may have a branched shape.

Further, as will be described later in the examples, when the concave portion 3 is formed by transferring the embossed pattern to the embossing of the adhesive layer, as the embossed pattern, a plurality of equilateral triangles, right triangles, squares, and rectangles may be provided. a polygonal shape such as a rhombus; a star-shaped polygon such as a pentagonal star or a hexagonal star; a circle; an ellipse; a fan shape; a shape of a repeating pattern formed by a shape such as a polygonal shape having a curved shape. Further, a shape which is a pattern such as a linen cloth or a non-shaped repeating pattern such as a pit-shaped shape such as a pear skin pattern, a granule, or a waterdrop pattern may be mentioned. Such an embossing pattern is not particularly limited as long as it can form a recess 3 which creates an independent space with the adherend, and it is preferable to form the independent recess 3, and it is preferable not to connect to the end. It is particularly preferable to be able to form a plurality of independent recesses 3.

The cross-sectional shape of the concave portion 3 is shown in Fig. 3, and can be semicircular (Fig. 3(a)), square (b), trapezoidal (c), and triangular (d). ) and a variety of shapes.

In the present embodiment, the concave portion 3 is formed by expanding the gas in the space between the concave portion 3 and the adherend by the pressure reduction treatment, thereby effectively reducing the adhesive force of the adhesive layer 2. It is preferable that the expanded gas is easily concentrated locally. Specifically, the shape of the concave portion 3 on the adhesive surface P is preferably a convex polygonal shape, a concave polygonal shape, or an amorphous shape.

The height of the concave portion 3 is preferably 2 μm or more and the thickness of the adhesive layer 2 or less, preferably 5 μm or more and the thickness of the adhesive layer 2 or less, more preferably 10 μm or more and more preferably the thickness of the adhesive layer 2 or less, and 20 μm or less. The above and the thickness of the adhesive layer 2 are particularly preferable. When the height of the concave portion 3 is 2 μm or more, a sufficient space can be generated between the concave portion 3 and the adherend, and the gas in the space can be effectively expanded.

The lower limit of the ratio of the area of the concave portion (hereinafter also referred to as the area ratio of the concave portion) with respect to the total area of the adhesive surface P is preferably 3% or more, more preferably 10% or more, and even more preferably 25% or more. Further, the upper limit of the area ratio of the concave portion is preferably 90% or less, more preferably 75% or less, and still more preferably 60% or less. When the recessed area ratio is 3% or more, since a sufficient space is formed between the recessed portion 3 and the adherend, the pressure obtained by the gas expansion in such a space is increased and the adhesive force can be obtained when the pressure reduction treatment is performed. Effectively reduced. On the other hand, when the area ratio of the concave portion is 90% or less, since the contact area with the adherend can be sufficiently ensured, the required adhesive force can be secured.

Here, the area ratio of the concave portion is a concave portion when the adhesive surface P is viewed in plan, and an image of the adhesive surface P is obtained by using a digital microscope at an imaging magnification of 20 to 100 times, and image processing (binarization processing) is performed on the image. It is measured by the total value of the area of the automatic area measurement recess. Specifically, the value calculated based on the following formula in the predetermined region D arbitrarily selected on the adhesive surface P can be regarded as the recess area ratio. The detailed measurement method is as disclosed in the examples to be described later.

As a method of forming the concave portion 3, for example, an embossing process in which an embossed pattern is transferred to an adhesive layer can be mentioned. At this time, the convex portion of the embossed pattern is transferred to the adhesive layer and becomes the concave portion 3 of the adhesive surface. Here, the ratio of the ratio of the area of the convex portion (hereinafter also referred to as the area ratio of the convex portion) to the total area of the surface (embossed surface) on which the embossed pattern is formed is preferably 30% or more, and 50% or less. More than % is particularly good, and more preferably 70% or more. Further, the upper limit of the area ratio of the convex portion is preferably 98% or less, more preferably 95% or less, and even more preferably 90% or less.

The area ratio of the convex portion of the embossed surface is not necessarily the same as the area ratio of the concave portion of the adhesive surface P when embossing is performed on the soft adhesive layer. However, even in such a case, when the convex portion area ratio of the embossed surface is in the above range, the adhesive surface P on which the embossed pattern is transferred is likely to fall within the above preferred range.

In the convex portion area of the embossed surface, the image of the embossed surface can be obtained by using a digital microscope, a laser microscope, an electron microscope, or the like at a magnification of 20 to 1000 times in a convex portion of the embossed surface. The image is subjected to image processing (binarization processing) and measured by the total area of the automatic area measurement convex area. Specifically, a value calculated based on the following formula can be regarded as a convex portion area ratio in a predetermined region T that is arbitrarily selected in the embossed surface. The detailed measurement method is disclosed in the examples described later.

As a method of forming the concave portion 3 other than the embossing, for example, a method of pattern printing to form the concave portion 3 may be employed, or the concave portion 3 may be formed by laser thermal processing of irradiating the adhesive layer with a laser. Further, as a method of forming the concave portion 3 having an irregular shape, the method described in International Publication No. 2015/152347 can also be exemplified. As a specific example, a coating film composed of a composition containing a large amount of fine particles and a small content of a resin, and a coating film composed of a composition containing a resin as a main component are separately formed. A method of simultaneously drying the two types of coating films. When such a method is used, it is considered that the shrinkage stress due to the fine particles is generated inside the coating film and the coating film is cracked, and the concave portion 3 can be formed by the resin film having such a coating film crack flowing into the periphery.

(3) Physical properties of the adhesive layer, etc. (3-1) Thickness The thickness of the adhesive layer in the present embodiment is preferably 5 to 100 μm, more preferably 10 to 50 μm, and even more preferably 15 to 30 μm. When the thickness of the pressure-sensitive adhesive layer is 5 μm or more, it is preferable because the space at the time of pressure reduction can be more ensured. When the thickness of the adhesive layer is 100 μm or less, it is preferable because the film thickness accuracy at the time of coating can be ensured.

(3-2) Adhesive force The adhesive force of the adhesive sheet is preferably 0.5 to 50 N/25 mm, preferably 2 to 40 N/25 mm, and particularly preferably 5 to 30 N/25 mm. When the adhesive force of the adhesive sheet is within the above range, the adherend can be surely fixed, for example, it is very useful to temporarily fix the adherend in the processing step of the adherend.

In addition, the adhesive force referred to here is a pressure-reducing treatment which is not described later (when the adhesive composition is active energy ray-curable or thermosetting, the active energy ray is not further irradiated and heated) For the sheet, the enamel mirror wafer was used as an adherend, and the adhesive sheet was attached to the mirror surface and the adhesion (mN/25 mm) measured according to the 180° peeling method of JIS Z0237:2009.

(3-3) Adhesion reduction rate The adhesion reduction rate of the adhesive sheet is preferably 10% or more, more preferably 20% or more, and particularly preferably 30% or more. When the adhesive force of the adhesive sheet is within the above range, the peeling of the adhesive sheet and the adherend in the present embodiment becomes easier.

In addition, the adhesion reduction rate referred to herein is the adhesion before the pressure reduction treatment described later (when the adhesive composition has active energy ray hardening property or thermosetting property, after the active energy ray is irradiated or heated). After the sheet and the pressure-sensitive adhesive sheet after the pressure-reducing treatment (when the adhesive composition has active energy ray-curing property or thermosetting property, after the active energy ray is irradiated and heated), the adhesive force is measured as described above, and Based on the obtained value, it was calculated according to the following formula. Adhesion reduction rate (%) = (adhesion before decompression - adhesion after decompression) / (adhesion before decompression) × 100

Further, as will be described later, the adhesive composition has irradiation or heating of the active energy ray at the time of active energy ray hardening or thermosetting, and may be an adhesive force in any case after the pressure reduction treatment or after the pressure reduction treatment. The reduction rate is calculated in accordance with the above formula.

(3-4) Stress relaxation ratio In the present embodiment, the lower limit of the stress relaxation rate of the adhesive layer is preferably 40% or more, more preferably 50% or more, and even more preferably 55% or more. The upper limit of the stress relaxation rate of the adhesive layer is preferably 90% or less, particularly preferably 85% or less, and more preferably 80% or less. By setting the stress relaxation ratio to the above range, the pressure-sensitive adhesive layer can be well balanced and stably deformed when the pressure is reduced.

In addition, the stress relaxation rate of the adhesive layer as used herein means that the pressure-reducing treatment described later is not performed (when the adhesive composition has active energy ray hardening property or thermosetting property, after the irradiation or heating of the active energy ray is performed) The adhesive layer was subjected to a tensile test to stretch it by 10% for 300 seconds. Specifically, the tensile test is an adhesive which is formed into a thickness of 50 μm, a width of 15 mm, and a length of 120 mm (in which the measurement range is 100 mm), and is elongated at a rate of 200 mm/min in an environment of 23° C. and 50% RH. % proceed.

(3-5) Elongation at break In the present embodiment, the lower limit of the elongation at break of the pressure-sensitive adhesive layer is preferably 110% or more, more preferably 120% or more, and still more preferably 130% or more. Further, the upper limit of the elongation at break of the pressure-sensitive adhesive layer is preferably 300% or less, more preferably 200% or less, and still more preferably 150% or less. By setting the elongation at break of the pressure-sensitive adhesive layer to the above range, the elongation can be well balanced and stably deformed when the pressure-sensitive adhesive layer is decompressed.

In addition, the elongation at break of the pressure-sensitive adhesive layer is not subjected to the pressure reduction treatment described later (when the adhesive composition has active energy ray hardening property or thermosetting property, after the active energy ray is irradiated or heated) The adhesive layer is measured by a separate adhesive layer without a substrate, and specifically, an adhesive having a thickness of 50 μm, a width of 15 mm, and a length of 120 mm (in which the measurement range is 100 mm) is formed. The film was extruded at a rate of 200 mm/min in an environment of 23 ° C and 50% RH.

(3-6) Gel fraction In the present embodiment, the lower limit of the gel fraction of the adhesive layer is preferably 2% or more, more preferably 4% or more, and still more preferably 6% or more. The upper limit of the gel fraction of the adhesive layer is preferably 90% or less, more preferably 40% or less, and even more preferably 15% or less. When the lower limit of the gel fraction of the adhesive layer is 2% or more, the reaction between the adhesives is caused by crosslinking, and the stability as an adhesive sheet can be ensured. On the other hand, when the upper limit of the gel fraction of the adhesive layer is 90% or less, it is easy to impart adhesiveness to the adhesive sheet and to obtain good temporary fixation.

In addition, the gel fraction of the adhesive layer is not subjected to the reduced pressure treatment described later (when the adhesive composition has active energy ray curability or thermosetting property, the active energy ray is not further irradiated. And heating) the value of the adhesive layer when attached (after the air drying period). Specifically, it means the gel fraction after the adhesive is applied to the release sheet and dried by heating, and stored in an environment of 23° C. and 50% RH for 7 days. Further, since the gel fraction of the adhesive is stable after passing through the seasoning period, it is unclear whether or not it has been stored in the environment of 23 ° C and 50% RH for 7 days after the air drying period. It can be measured.

(4) Substrate The adhesive sheet of the present embodiment may be provided with a substrate in addition to the adhesive layer. Here, the base material is not particularly limited as long as the adhesive sheet can have an appropriate function in a step required for the processing step of the adherend, and the like. For example, a paper base material, a resin film, or a resin may be used. The base material to which the sheet and the paper base material are bonded can be appropriately selected in accordance with the use of the adhesive sheet of one embodiment of the present embodiment. In particular, it is preferable that the pressure-reducing effect is a film made of a resin-based material as a main material. Specific examples of the film include an ethylene-vinyl acetate copolymer film, an ethylene-(meth)acrylic copolymer film, and an ethylene-based (meth)acrylate copolymer film; Polyethylene film (LDPE) film, linear low-density polyethylene (LLDPE) film, high-density polyethylene (HDPE) film, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethyl a polyolefin-based film such as a pentene film, an ethylene-norbornene copolymer film or a norbornene resin film; a polyvinyl chloride film such as a polyvinyl chloride film or a vinyl chloride copolymer film; and polyethylene terephthalate A polyester film such as a diester film or a polybutylene terephthalate film; a polyurethane film; a polyimide film; a polystyrene film; a polycarbonate film; a fluororesin film. Further, such a crosslinked film, a modified film such as an ionic polymer film may also be used. The substrate may be a film composed of one of these types, or a laminate film in which two or more types are combined.

The film constituting the substrate preferably contains at least one of a vinyl copolymer film and a polyolefin film. The ethylene-based copolymer film is easy to control its mechanical properties in a wide range by changing the copolymerization ratio and the like. Therefore, the base material provided with the ethylene-based copolymer film can easily satisfy the mechanical properties required as the base material of the pressure-sensitive adhesive sheet of the present embodiment. Further, since the ethylene-based copolymer film has high adhesion to the pressure-sensitive adhesive layer, when it is used as an adhesive sheet, peeling at the interface between the substrate and the pressure-sensitive adhesive layer is less likely to occur.

In the base material used in the present embodiment, various additives such as a pigment, a dye, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and a filler may be contained in the film containing the resin material as a main material. Examples of the pigment include titanium dioxide, carbon black, and the like. Further, examples of the filler include an organic material such as a melamine resin, an inorganic material of fumed silica, and a metal material such as nickel particles. The content of such an additive is not particularly limited, but it must be left in a range in which the function required for the substrate can be exhibited without losing smoothness and flexibility.

When ultraviolet rays are used as the energy ray for curing the adhesive layer and irradiated from the substrate side, the substrate is preferably transmissive to ultraviolet rays. Further, when an electron ray is used as the energy ray, the substrate preferably has electron beam transmittance. However, when the adherend has energy ray transmission and the energy ray is irradiated from the side of the adherend, the substrate does not have to have energy ray transmission.

Further, the surface of the adhesive layer side of the substrate (hereinafter also referred to as "the substrate-attached surface") has one or more components selected from the group consisting of a carboxyl group and an ion and a salt thereof. It is better. By chemically interacting with the above-mentioned components in the substrate and the adhesive layer component (the components used to form the adhesive layer such as the components constituting the adhesive layer and the crosslinking agent), it is possible to reduce the chemical interaction. There is a possibility of peeling between them. The specific method for causing such a component to be present on the adhesive surface of the substrate is not particularly limited. For example, the base material itself may be an ethylene-(meth)acrylic copolymer film or an ionomer resin film, and the resin constituting the material of the substrate may be selected from the group consisting of a carboxyl group and a group of ions and salts thereof. One or more types. As another method of allowing the above-mentioned components to be present on the adhesive surface of the substrate, for example, the base material is a polyolefin-based film, and the base material may be subjected to corona treatment on the side of the adhesive surface or a primer layer may be provided. Further, various coating films may be provided on the surface of the substrate opposite to the surface on which the substrate is adhered.

The thickness of the substrate is not limited as long as the adhesive sheet can have an appropriate function in a desired step, and preferably 5 to 1000 μm, preferably 10 to 500 μm, more preferably from the viewpoint of workability and economy. It is 12 to 250 μm, and more preferably 15 to 150 μm.

(5) Release sheet The adhesive sheet of the present embodiment may be formed by laminating the release sheet on the adhesive surface of the adhesive layer for the purpose of protecting the adhesive layer while the adhesive layer is attached to the adhesive. . The configuration of the release sheet is arbitrary, and a product obtained by peeling off a plastic film using a release agent or the like can be exemplified. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polycondensation of polypropylene, polyethylene, and the like. Olefin film. As the release agent, a polyfluorene-based, a fluorine-based or a long-chain alkyl group can be used, and among these, a polyoxyl system which is inexpensive and can provide stable performance is preferable. The thickness of the release sheet is not particularly limited, and is usually about 20 to 250 μm. Moreover, such a release sheet may be a release sheet which forms an embossed pattern for forming a concave portion, or a release sheet which is a flat surface and which is formed by laminating the adhesive layer after the concave portion is formed.

(6) Method for Producing Adhesive Sheet The method for producing an adhesive sheet is to form an adhesive layer formed of the above-described adhesive composition, and a method of forming a concave portion on an adhesive surface of the adhesive layer is not particularly limited. . As an example, first, a sheet having an embossed pattern corresponding to a concave portion is prepared, and a release sheet having an embossed pattern is obtained by subjecting the surface of the sheet to a peeling treatment. Then, a coating composition containing the above-described adhesive composition and a solvent or a dispersion medium further contained as required is prepared, and a die coater is used on the release-treated surface of the release sheet having an embossed pattern as described above. The coating composition is applied to the coating composition by a curtain coater, a spray applicator, a slit coater, a knife coater, etc., and the coating film is dried to form an adhesive layer and a release sheet. Laminated body. Next, the substrate can be attached to the surface of the laminate which is opposite to the surface on the side of the release sheet of the adhesive layer, thereby obtaining a laminate of the adhesive sheet and the release sheet. The release sheet of the laminate may be peeled off as a process material, and the adhesive layer may be protected until the adhesive sheet is attached to an adherend such as an electronic component or an optical member.

In this case, the coating composition is not particularly limited in its properties as long as it can be applied, and the component for forming the pressure-sensitive adhesive layer may be contained as a solute, or may be contained as a dispersoid. Further, when the coating composition contains a crosslinking agent, the (meth) acrylate polymer (A) in the coating film is changed by changing the drying conditions (temperature, time, etc.) or by separately providing heat treatment. (B1) or (B3) may be subjected to a crosslinking reaction with a crosslinking agent and a crosslinked structure may be formed in the adhesive layer at a desired density of existence. In order to sufficiently carry out the crosslinking reaction, after the adhesive layer is laminated on the substrate by the above-described method or the like, the obtained adhesive sheet is usually allowed to stand for several days in an environment of, for example, 23 ° C and a relative humidity of 50%. Ripening. In addition, the term "crosslinking" of the adhesive in the present specification refers to a reaction in which the adhesive sheet is adhered to the adherend before the adherend, and the adhesive layer is formed, for example, before the adhesive is adhered. Therefore, the "crosslinking" of the adhesive can be clearly distinguished from the "hardening" which will be described later.

As a separate manufacturing method of the adhesive sheet, laser processing using laser irradiation instead of embossing can be performed. Specifically, after the adhesive sheet of the laminate of the adhesive layer and the substrate is obtained as described above, the laser is irradiated from the adhesive surface side of the adhesive layer to form a concave portion. Examples of the types of lasers used in laser thermal processing include carbon dioxide gas (CO ₂ ) lasers, TEA-CO ₂ lasers, YAG lasers, UV-YAG lasers, YVO ₄ lasers, and YLF lasers. Etc. Among them, in particular, in terms of production efficiency, cost, etc., a carbon dioxide gas laser is preferred.

Further, a through hole is formed by laser thermal processing, and a plurality of laser beams are continuously irradiated to form a through hole (pulse mode), and a plurality of laser beams are sequentially irradiated to a plurality of portions to uniformly form a plurality of laser beams. The cyclic processing of the through hole (circulation mode) is superior in terms of thermal efficiency, and the thermal influence on the workpiece can be reduced. The latter is superior, and the above laser thermal processing can adopt either mode. And proceed.

[Method for peeling adhesive sheet and method for producing processed product] The method for peeling the adhesive sheet from the adhered surface adhered to the adhesive surface of the adhesive layer by using the above-mentioned adhesive sheet is as follows with reference to Fig. 4 Be explained.

(1) Adhesive step First, when the peeling method of the present embodiment is carried out, as shown in Fig. 4(a), the workpiece W as an adherend is previously adhered to the adhesive surface of the adhesive layer 2 provided in the adhesive sheet 1. P. As described above, the concave portion 3 is formed on the adhesive surface P of the adhesive layer 2, and the workpiece W is adhered to the adhesive sheet 1 so as to create a separate space C between the concave portion 3 and the workpiece W. Here, the space C is independent, and means that the space C and the adhesive surface P are not in contact with the end portion E of the portion to be adhered. By the space C being independent, the space C can be expanded by the pressure reduction process in the peeling process mentioned later.

Examples of the workpiece W to be subjected to the peeling method of the present embodiment include electronic components such as a semiconductor wafer, a semiconductor component, a multilayer substrate, a ceramic green sheet laminate, and a bulk seal module; and a liquid crystal display member and an organic EL; Optical members such as a display member, an optical filter, a polarizing plate, and a phase difference plate.

The adhesion of the workpiece W to the adhesive sheet 1 can be performed under atmospheric pressure, or can be performed in a processing chamber under controlled environmental pressure by a pressure control device 10 to be described later. Here, the atmospheric pressure in the pasting step or the environmental pressure in the processing chamber is equivalent to the gas pressure in the space C in the subsequent step, and the environmental pressure is appropriately adjusted to perform the sticking step, and it is easy to control the pressure reducing treatment. The amount of expansion of the gas.

(2) Processing step The workpiece W adhered to the adhesive sheet 1 by the bonding step can be subjected to various processing steps while being adhered to the adhesive sheet 1 (Fig. 4(b)). As an example of the processing step, when the workpiece W is a semiconductor wafer, a back surface polishing step, a circuit forming step, a dicing step, a die sorting step, and the like may be mentioned; and when the workpiece W is a display device constituting member, The stacking step, the transfer step, and the like. By these various steps, the workpiece W is processed into a workpiece W'. Here, since the adhesive sheet 1 is peeled off from the workpiece W after the processing step of the workpiece W as will be described later, it can be used to temporarily fix the workpiece W between the steps.

(3) Peeling step Next, the adhesive sheet 1 in a state in which the workpiece W' is adhered is placed in the processing chamber of the pressure control device 10 (Fig. 4(c)). Here, in order to effectively expand the space C in the pressure reduction treatment to be described later, the adhesive sheet 1 in a state in which the workpiece W' is adhered is placed on the processing so that the workpiece W' is placed on the lower side of the adhesive sheet 1. The interior is better. However, the weight of the workpiece W' is sufficiently small (especially when the workpiece W' is lighter than the adhesive sheet 1), and when the space C is expanded by the pressure reduction treatment, the workpiece W' can also be formed. The upper side of the sheet 1 is adhered to the processing chamber.

Next, the pressure in the processing chamber is lowered (pressure reducing treatment, Fig. 4 (d)). As a result, since the gas pressure in the space C becomes a relatively high state compared to the pressure in the processing chamber, the volume expansion in the gas in the space C makes it possible to adhere the adhesive in the adhesive layer 2. Layer 2 imparts a pressure that causes space C to expand.

Such a pressure imparts a pressure suitable for expanding at least the space C in a direction along the longitudinal direction (the normal direction of the adhesive surface P of the adhesive layer 2). Here, when the adhesive layer 2 has a plurality of recesses 3, when a plurality of spaces C are formed, the pressure in the lateral direction (the plane direction of the adhesive surface P of the adhesive layer 2) to which one space C is imparted is adjacent to The space C of the space C is offset by the lateral pressure given, since the longitudinal pressure is not left by the offset, so that the force for expanding the space C to the longitudinal direction becomes more remarkable, which is preferable.

The pressure reduction treatment is preferably lower than the environmental pressure of the attached environment, and the environmental pressure in the treatment chamber is preferably lower than the environmental pressure of the attached environment by 10 kPa or more, and the difference in the environmental pressure is 30 kPa or more. More preferably, it is more preferably 50 kPa or more, more preferably 80 kPa or more, and more preferably 90 kPa or more. By performing the above-described pressure reduction treatment in a manner lower than the environmental pressure of the attached environment, the gas in the space C can be more effectively expanded. Further, the lower limit of the pressure in the treatment chamber is not particularly limited, and is usually 10 ^-7 Pa or more, preferably 10 ^-5 Pa or more, more preferably 10 ^-1 Pa or more, and more preferably from a technical point of view. Preferably, it is 10 Pa or more, and more preferably 100 Pa or more, and particularly preferably 1000 Pa or more.

As a result of such a reduced pressure treatment, as shown in Fig. 4(d), the force of pushing the substrate toward the longitudinal direction of the adhesive by the expansion of the space C is greater than the adhesion to the adherend, from where The adhesive layer 2 is peeled off from a part or all of the workpiece W' (Fig. 4(e)). Since the adhesive layer 2 has a plurality of concave portions 3, since a plurality of spaces C are formed, the expansion portion is increased, and as a result, the chance of peeling is increased, which is preferable. Further, the adhesive layer 2 may be either rigid or soft. When the adhesive layer 2 is relatively hard, as shown in Fig. 4(d), in the state where the deformation of the space C and the adhesive layer 2 is hardly observed, the peeling of the interface between the adhesive layer 2 and the workpiece W' is Gradually proceed from the space C side. It is considered that this is because the pressure generated by the expansion of the gas is easily concentrated in the weaker portion, that is, the adhesive layer 2 and the workpiece W, in the inner wall of the space C composed of the adhesive layer 2 and the workpiece W'. 'The reason for the interface. On the other hand, when the adhesive layer 2 is relatively soft, after the space C and the adhesive layer 2 are longitudinally deformed, as shown in Fig. 4(e), the adhesive layer 2 and the workpiece W' are peeled off. In this manner, the adhesion of the adhesive layer 2 to the workpiece W' is lowered. Thereby, the adhesive sheet 1 and the workpiece W' can be easily peeled off. Here, the adhesive sheet 1 and the workpiece W' can be directly peeled off in the state of FIG. 4(e), for example, the workpiece W' is placed on the upper side of the adhesive sheet 1 and placed in the processing chamber to be decompressed. At the time of reversing the workpiece W' and the adhesive sheet by 180° in the treatment chamber after the pressure reduction, the adhesive sheet 1 and the workpiece W' can be peeled off by the weight of the workpiece W'.

Further, when the adhesive composition forming the adhesive layer 2 has active energy ray hardening property or thermosetting property, the above-described processing step is performed by irradiation or heating with active energy rays before or after the pressure reduction treatment. It is preferred that the adhesive layer 2 is hardened. Here, when the adhesive layer 2 is hardened before the pressure reduction treatment, since the adhesive layer 2 becomes relatively hard at the time of the pressure reduction treatment, as described above, the space C and the adhesive layer 2 hardly deform, in the adhesive layer. The peeling of the interface with the workpiece W' is started from the space C side, and the adhesion between the adhesive layer 2 and the workpiece W' can be lowered. On the other hand, when the adhesive layer 2 is hardened after the pressure reduction treatment, since the adhesive layer 2 is soft at the stage of the reduced pressure treatment, the space C and the adhesive layer 2 are deformed (Fig. 4 (d) After the adhesive layer 2 is cured, the adhesive force can be further lowered, and the adhesive layer 2 and the workpiece W' can be easily peeled off. In the present specification, the term "hardening" of the adhesive refers to a reaction performed after the adherend (the workpiece W and the workpiece W') is adhered to the adhesive sheet 1. Therefore, it is possible to clearly distinguish from "crosslinking" of the above-mentioned so-called adhesive.

When the adhesive composition has active energy ray curability, the active energy ray for curing the adhesive composition includes ionizing radiation, that is, ultraviolet rays, X-rays, and electron beams. Among these, it is particularly preferable to use ultraviolet rays which are relatively easy to introduce into the irradiation apparatus.

When ultraviolet rays are used as the ionizing radiation, it is sufficient to use near-ultraviolet rays containing ultraviolet rays having a wavelength of about 200 to 380 nm in terms of ease of handling. The amount of light may be appropriately selected according to the type of active energy ray-curable group of the active energy ray-curable adhesive composition and the thickness of the adhesive layer 2, and is usually about 50 to 1500 mJ/cm ² and 200 Å. It is preferably 1000 mJ/cm ^{2 and} preferably 300 to 800 mJ/cm ² . Further, the intensity of ultraviolet generally 50 ~ 1500mW / cm ^2, and at 200 ~ 1000mW / cm ² preferably, to 300 ~ 800mW / cm ² is preferred. The ultraviolet light source is not particularly limited, and for example, an electrodeless lamp, a high pressure mercury lamp, a halogenated metal lamp, a UV-LED, or the like can be used.

When an electron beam is used as the ionizing radiation, the acceleration voltage is appropriately selected according to the active energy ray-curable group type of the active energy ray-curable adhesive composition and the thickness of the adhesive layer 2, and the acceleration voltage is usually used. It is preferably about 10~1000kV. Further, the irradiation amount is set to a range in which the active energy ray-curable adhesive composition is appropriately cured, and is usually selected in the range of 10 to 1000 krad. The electron beam source is not particularly limited, and for example, a Cockroft-Walton type, a Vande Graaff type, a resonant transformer type, an insulated core transformer type, or a linear type can be used. Various electron ray accelerators such as high-frequency high-voltage electron accelerators (dynamitrons) and high-frequency type.

From the viewpoint of effectively curing the adhesive composition, it is preferable that the active energy rays are irradiated from the side opposite to the adhesive surface P (the surface to which the workpiece W' is adhered).

On the other hand, when the adhesive composition has thermosetting properties, as a heating means for curing the adhesive composition, for example, a suitable means such as a hot plate, a hot air dryer, or a near-infrared lamp can be used. The heating condition is a heating temperature required for thermal curing of the adhesive layer 2, and can be appropriately set in accordance with the required peeling property, heat resistance of the workpiece W and the workpiece W', heating means, and the like. As a general heating condition, for example, when a hot plate is used, a temperature of 80 to 250 ° C, a heating time of 5 seconds to 60 seconds, and the like can be exemplified.

According to the peeling method of the adhesive sheet of the embodiment described above, the adhesive layer 2 of the adhesive sheet 1 forms a space C between the concave portion 3 of the adhesive surface P and the adherend (the workpiece W and the workpiece W'). By the pressure reduction treatment of expanding the gas in the space C, the adhesion of the adhesive sheet 1 to the adherend is lowered. When such a method is used, the adhesive action can be reduced at a desired timing by a novel action mechanism for expanding the gas by the pressure reduction treatment, whereby the adhesive sheet and the adherend can be easily peeled off.

Here, when the adhesive strength of the adhesive layer 2 is lowered by the active energy ray hardening property or the thermosetting property, the material selection is limited in order to sufficiently perform the curing reaction (that is, the chemical reaction). However, according to the present embodiment, the adhesive force can be reduced by the expansion of the gas generated by the pressure reduction treatment, and the active energy ray hardenability or the thermosetting property or the partial use can be eliminated at all. The degree of freedom of the material of the adhesive layer 2 becomes large. Moreover, when the adhesive force of the adhesive layer 2 is lowered by thermosetting property, when the heating step is included in the processing step of the workpiece W, the adhesive force of the adhesive layer 2 is lowered, so that the workpiece W cannot be sufficiently performed in the processing step. Although it is temporarily fixed, in the present embodiment, since the thermosetting property is not used at all or only partially used, even when the heating step is included in the processing step of the workpiece W, the workpiece W can be sufficiently temporarily fixed.

The embodiments described above are described in order to facilitate the understanding of the present invention and are not intended to limit the present invention. Therefore, the respective elements disclosed in the above embodiments are intended to include all design changes, equivalents, and equal methods of the technical scope of the present invention.

For example, the substrate 4 of the adhesive sheet 1 and the adhesive layer 2 may be interposed between other layers.

Further, in another embodiment, the adhesive sheet may be a double-sided adhesive sheet which is not provided with a substrate but has only an adhesive layer. For example, in another embodiment, a method of peeling off the first adherends having the first adhesive surface and the second adhesive surface and peeling off the first adherend adhered to the first adhesive surface can be used. On the second adhesive surface, for example, a second adherend may be adhered. At this time, similarly to the above-described embodiment, the first adhesive surface is formed with a concave portion, and the first adherend is adhered to the adhesive layer so that an independent space is formed by such a concave portion. By decompressing the first adherend and the adhesive sheet (and the second adherend), the gas in the space expands, and the adhesion of the double-sided adhesive sheet to the first adherend is lowered, thereby enabling the first 1 The adhesive is peeled off from the adhesive sheet. [Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the scope of the invention is not limited by the examples and the like.

[Example 1] (a) Production of a release sheet A polyethylene terephthalate film (manufactured by TORAY Co., Ltd., product name "Lumirror", thickness: 75 μm) was used as the pattern of Fig. 5 (a). An embossed film (1) is obtained by embossing. In the embossed surface of the embossed film (1), a release agent having the same composition as the release agent of the release sheet (manufactured by LINTEC Co., Ltd., product name "SP-PET381130") is used as a release agent, and after drying, The thickness was 0.1 μm, and it was dried at 130 ° C for 30 seconds to produce a release sheet (1) having an embossed pattern on the surface.

(b) Preparation of an adhesive A (meth) acrylate copolymer obtained by copolymerizing 52 parts by mass of n-butyl acrylate, 20 parts by mass of methyl methacrylate and 28 parts by mass of 2-hydroxyethyl acrylate (relative to The (meth) acrylate copolymer has a hydroxyl group of 100 equivalents, and is reacted by adding 90 equivalents of methacryloyloxyethyl isocyanate (MOI), and has a weight average molecular weight of 580,000 and a solid content concentration of 35 mass%) 100. Parts by mass (solid content by mass), energy ray-hardening urethane acrylate oligomer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "Purple UV-6100B", mass average molecular weight 6700, glass transition temperature 0 °C) 100 parts by mass (solid content), isocyanate-based crosslinking agent (manufactured by TOSOH Co., Ltd., product name "CORONATE L", solid content concentration: 75 mass%) 0.4 parts by mass (solid content parts by mass), and as photopolymerization The energy ray-curable adhesive was prepared by mixing 3.0 parts by mass of a 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF Corporation, product name "IRGACURE 184").

Here, the polystyrene-equivalent weight average molecular weight is a standard polystyrene conversion measured by a gel permeation chromatography apparatus (product name "HLC-8020" manufactured by TOSOH Co., Ltd.) under the following conditions (GPC measurement). value.

<GPC measurement conditions> ‧ Pipe column: "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL", and "TSK gel G1000HXL" (all of which are manufactured by TOSOH Co., Ltd.) are sequentially connected. Into the material column temperature: 40 ° C ‧ development solvent: tetrahydrofuran ‧ flow rate: 1.0mL / min ‧ detector: differential refractometer ‧ standard sample: polystyrene

(c) Production of Adhesive Sheet The thickness of the energy ray-curable adhesive prepared in the above (b) is 50 μm from the apex of the embossing on the peeling-treated surface of the release sheet produced in the above (a). The coating was applied using a knife coater and dried at 110 ° C for 2 minutes to form an adhesive layer. A polyethylene terephthalate film (manufactured by Mitsubishi Plastics Co., Ltd., product name "Diafoil", thickness: 50 μm) as a substrate was bonded to the obtained adhesive layer, followed by a relative humidity of 50 at 23 ° C. It was air-dried for 7 days under conditions and used as an adhesive sheet.

[Example 2] A polyethylene terephthalate film (product name "Lumirror", manufactured by TORAY Co., Ltd., thickness: 75 μm) was subjected to embossing to obtain a pattern as shown in Fig. 6 (a). Floral membrane (2). A release agent having the same composition as that of the release agent of the release sheet (manufactured by LINTEC Co., Ltd., product name "SP-PET381130") was used as a release agent, and the embossed film was applied by a wire bar so that the thickness after drying became 0.1 μm. The embossed surface of 2) was dried at 130 ° C for 30 seconds to produce a release sheet (2) having an embossed pattern on the surface. An adhesive sheet was produced in the same manner as in Example 1 except that the obtained release sheet (2) was used.

[Example 3] A polyethylene terephthalate film (manufactured by TORAY Co., Ltd., product name "Lumirror", thickness: 75 μm) was subjected to embossing to obtain a pattern as shown in Fig. 7 (a). Floral membrane (3). A release agent having the same composition as that of the release agent of the release sheet (manufactured by LINTEC Co., Ltd., product name "SP-PET381130") was used as a release agent, and the embossed film was applied by a wire bar so that the thickness after drying became 0.1 μm. The embossed surface of 3) was dried at 130 ° C for 30 seconds to produce a release sheet (3) having an embossed pattern on the surface. An adhesive sheet was produced in the same manner as in Example 1 except that the obtained release sheet (3) was used.

<Measurement of the area ratio of the convex portion of the embossed surface> The embossed surface (the peeled surface having the embossed pattern) of the release sheet used in each of the examples was vertically oriented from the top using a digital microscope (magnification: 20 to 50 times). The direction is taken to an arbitrarily selected range to obtain an image. Further, more specifically, at the time of the photographing, the photographing is performed by visually aligning the focus corresponding to the side (non-convex portion) of the succeeding surface from the vertical direction. Further, in the acquired image, one region is arbitrarily selected in a region T surrounded by a predetermined rectangle, and this is referred to as "image of region T". Here, in the selection of the region T, the peeling sheet (1) is selected to be 4 mm in length × 5 mm in width, and the peeling sheet (2) is 8 mm in length × 10 mm in width, and the peeling sheet is selected in consideration of ease of recognition and regularity of the embossed pattern. 3) is 2 mm in length × 2.5 mm in width. Moreover, the shooting conditions of the digital microscope are as follows.

(measurement machine) KEYENCE system, product name "digital microscope VHX-5000", high resolution variable focus lens VHX-ZST100 times (measurement conditions) Recording mode: HDR shooting Edge emphasis: OFF

Next, based on the acquired "image of the region T", the automatic area measurement is performed using the same digital microscope as described above, and the area of each convex portion existing in the region T is obtained. In the automatic area measurement, first, by using image processing by a digital microscope, the boundary of the convex portion existing in the region T is demarcated and binarized to obtain a binarized image. Further, in the case where the image processing of the digital microscope cannot determine the boundary of the convex portion, the binarized image is obtained by dividing the boundary of the convex portion by manual input while referring to the "image of the region T". Next, the binarized image value (area) obtained by the measurement was measured, and the total area of all the convex portions was measured. Subsequently, the convex portion area ratio was calculated based on the following formula. The measurement results are shown in Table 1. The area ratio of the convex portion = [the area of the convex portion in the region T / the total area of the region T] × 100, and the binarized images obtained for the embossed surfaces of the peeling sheets of Examples 1 to 3 are each displayed in the fifth Figure (b), Figure 6 (b), and Figure 7 (b).

<Measurement of the area ratio of the concave portion of the adhesive surface> The adhesive surface of the adhesive sheet obtained in each of the examples was bonded to a glass plate (manufactured by Corning Co., Ltd., product name "EAGLE XG"), and the glass substrate was placed on the surface. Using a digital microscope (20 to 50 times magnification), an image is obtained by photographing an arbitrarily selected range from the upper side in the vertical direction. The obtained images are shown in Fig. 8(a), Fig. 9(a), and Fig. 10(a). Further, in the case of the photographing, the focus is moved from the upper side of the portion determined to be the non-recessed portion by the visual direction from the vertical direction, and the portion having the focus is started as the non-recessed portion. In the obtained connected image, one region is arbitrarily selected from the region D surrounded by a rectangle of 6 mm in length and 8 mm in width, and this is referred to as "image of region D". Moreover, the shooting conditions of the digital microscope are as follows.

(measurement machine) KEYENCE system, product name "digital microscope VHX-5000", high resolution variable focal length lens VHX-ZST100 times (measurement conditions) ‧ vertical illumination type illumination: ON ‧ stage transmission illumination: OFF ‧ illumination Transformation: coaxial vertical illumination ‧ edge emphasis: OFF

Next, based on the acquired "image of the region D", the automatic area measurement is performed using the same digital microscope as described above, and the area of each concave portion existing in the region D is obtained. In the automatic area measurement, first, by using image processing by a digital microscope, the boundary of the concave portion existing in the region D is demarcated and binarized to obtain a binarized image. Further, in the case where the image processing of the digital microscope cannot define the boundary of the concave portion, the binarized image is obtained by dividing the boundary of the concave portion by manual input while referring to the "image of the region D". Next, the binarized image value (area) obtained by the measurement was measured, and the total area of all the concave portions was measured. Subsequently, the recess area ratio was calculated based on the following formula. The measurement results are shown in Table 1. The area ratio of the concave portion = [the area of the concave portion in the region D / the total area of the region D] × 100. The binarized images obtained for the adhesive faces of the adhesive sheets of Examples 1 to 3 are each shown in Fig. 8 (b). ), Figure 9 (b), and Figure 10 (b).

<Adhesion force (before UV irradiation)> The adhesive sheet obtained in each Example was cut into a size of 25 mm in length × 300 mm in width, and then attached to the environment at 23° C. and 50% RH (relative humidity). A glass plate (manufactured by Nippon Sheet Glass Co., Ltd., soda lime glass, 150 mm in length × 70 mm in width × 2 mm in thickness) was allowed to stand in the same environment for 24 hours. After standing, the adhesion of each of the adhesive sheets was measured in accordance with JIS Z0237:2000 and using a 180° peeling method at a stretching speed of 300 mm/min. The measurement results are shown in Table 1.

<Adhesion (after UV irradiation)> The adhesive sheet obtained in each example was cut into a size of 25 mm in length × 300 mm in width, and then attached to the environment at 23° C. and 50% RH (relative humidity). A glass plate (manufactured by Nippon Sheet Glass Co., Ltd., soda lime glass, 150 mm in length × 70 mm in width × 2 mm in thickness) was allowed to stand in the same environment for 24 hours. Then, it was allowed to stand in a processing chamber made of quartz glass, and irradiated with ultraviolet rays by a irradiation ultraviolet ray irradiation device (product name "Light Hammer 10MARK II", an electrodeless lamp, manufactured by Hearaus Co., Ltd.), and then irradiated with ultraviolet rays from a distance of 2 cm on the quartz glass. The adhesive sheet and the glass plate were taken out from the processing chamber, and the adhesion of each of the adhesive sheets was measured in accordance with JIS Z0237:2000 using a 180° peeling method at a stretching speed of 300 mm/min. The measurement results are shown in Table 1. The ultraviolet irradiation conditions are in the range of 200 to 380 nm, the illuminance is 700 mW/cm ² , and the amount of light is 700 mJ/cm ² . The illuminance and the amount of light are measured by using an illuminance meter (product name "UV Power Puck II" manufactured by EIT Co., Ltd.). The illuminance and the amount of light are measured.

<Measurement of adhesion (after UV irradiation and after decompression)> The adhesive sheets obtained in the respective examples were cut into a size of 25 mm in length × 300 mm in width, and then in an environment of 23° C. and 50% RH (relative humidity). It was attached to a glass plate (manufactured by Nippon Sheet Glass Co., Ltd., soda lime glass, 150 mm in length × 70 mm in width × 2 mm in thickness) and allowed to stand in the same environment for 24 hours. After standing, it was irradiated with ultraviolet light from a quartz glass in a processing chamber made of quartz glass and irradiated with ultraviolet light at a distance of 2 cm from a quartz glass using an ultraviolet irradiation apparatus (manufactured by Hearaus Co., Ltd., product name "Light Hammer 10MARK II", an electrodeless lamp). The pressure reducer connected to the processing chamber by using a hose is depressurized until the ambient pressure in the processing chamber becomes 2 kPa and is maintained for 10 seconds, and then the pressure-reduced state is released and the adhesive sheet and the glass plate are taken out from the processing chamber. The adhesion of each of the adhesive sheets was measured in accordance with JIS Z0237:2000 at a tensile speed of 300 mm/min using a 180° peeling method. The measurement results are shown in Table 1. The ultraviolet irradiation conditions were set to the same conditions as those of <adhesion force (after UV irradiation)>.

<Adhesion reduction rate> The adhesion reduction rate was calculated according to the following formula. The results are shown in Table 1. Adhesion reduction rate (%) = (adhesion after UV irradiation - adhesion after decompression) / (adhesion after UV irradiation) × 100

<stress relaxation rate> In each of the examples, the embossed film was changed to a heavy release sheet (manufactured by LINTEC Co., Ltd., product name "SP-PET382050", thickness 38 μm, and poly(p-phenylene) coated with a polyoxynitride-based release agent. The ethylene glycol formate film was changed to a light release sheet (manufactured by LINTEC Co., Ltd., product name "SP-PET381031", 38 μm thick, polyethylene terephthalate coated with a polyoxynitride-based release agent). A film-free double-sided adhesive sheet held by two release sheets was produced in accordance with the procedure described in the examples, except that the thickness of the adhesive layer after drying was 50 μm. The non-substrate double-sided adhesive sheet was allowed to stand in an environment of 23° C. and 50% RH for 2 weeks, and irradiated with ultraviolet rays using an ultraviolet irradiation apparatus (manufactured by Hearaus Co., Ltd., product name “Light Hammer 10MARK II”, an electrodeless lamp). The ultraviolet irradiation conditions are in the range of 200 to 380 nm, the illuminance is 700 mW/cm ² , and the amount of light is 700 mJ/cm ² . The illuminance and the amount of light are measured using an illuminance meter (product name "UV Power Puck II" manufactured by EIT Corporation. ) and measure the illuminance and amount of light.

Subsequently, a sample having a length of 15 mm width × 120 mm was cut out from an adhesive sheet in which a plurality of layers of the above-mentioned adhesive layer were laminated, and the peeling sheet laminated on the outermost layer of the laminated body was peeled off and the measurement range was 15 mm in width. The sample was attached to a universal tensile tester (manufactured by Shimadzu Corporation, AUTOGRAPH AG-10kNIS). Further, the sample was elongated at a tensile speed of 200 mm/min in an environment of 23 ° C and 50% RH (relative humidity) to measure the stress A (Pa) at 10% elongation and the stress after 300 seconds from the stop of elongation. B (Pa). The measurement was measured only in the MD direction, that is, in the direction parallel to the application direction of the adhesive. From the measured stress A and stress B, the stress relaxation rate (%) was calculated using the following formula. The measurement results are shown in Table 1. Stress relaxation rate (%) = {(A-B) / A} × 100 (%)

<Elongation at break> The sample of the same shape and size as the sample used for the measurement of the stress relaxation rate is attached to the omnipotent so that the sample measurement range becomes 15 mm width × 100 mm in length, similarly to the measurement of the stress relaxation rate. Tensile testing machine (manufactured by Shimadzu Corporation, AUTOGRAPH AG-10k NIS). Then, the sample was stretched at a tensile speed of 200 mm/min in an environment of 23 ° C and 50% RH (relative humidity), and the sample length C (mm) at the time of the fracture was measured. The measurement was measured only in the MD direction, that is, in the direction parallel to the application direction of the adhesive. The elongation at break (%) was calculated from the sample length C (mm) at the time of the fracture using the following formula. The measurement results are shown in Table 1. Elongation at break (%) = {C / length of sample before measurement} × 100 (%)

<Gel fraction> The adhesive sheet obtained in the example was cut into a size of 80 mm × 80 mm, and the adhesive layer from which the release sheet was removed was made of a polyester mesh (mesh number: 200 mesh/inch) Wrapped and used precision balances to weigh only the quality of the adhesive. Set the quality at this time to M1. Next, the sample of the above adhesive was immersed in an ethyl acetate solvent at room temperature (23 ° C) for 24 hours. Subsequently, the adhesive was taken out and air-dried for 24 hours in an environment of a temperature of 23 ° C and 50% RH, and further dried in an oven at 80 ° C for 12 hours. Use a precision balance to weigh only the quality of the adhesive after drying. Set the quality at this time to M2. The gel fraction (%) is represented by (M2/M1) × 100. The measurement results are shown in Table 1.

[Table 1]

As shown in Table 1, it was confirmed that any of Examples 1 to 3 was subjected to pressure reduction treatment, and the adhesion was lowered, and the adhesion between the pressure-sensitive adhesive sheet and the adherend was facilitated.

1‧‧‧Adhesive film

2‧‧‧Adhesive layer

3‧‧‧ recess

4‧‧‧Substrate

P‧‧‧ adhesive surface

C‧‧‧ Space

W‧‧‧Workpiece

W’‧‧‧Processing

E‧‧‧End

10‧‧‧ Pressure control device

Fig. 1 is a cross-sectional view showing an adhesive sheet used in an embodiment of the present invention. Fig. 2 is a plan view schematically showing an adhesive surface of an adhesive layer of an example of a shape of a concave portion. Fig. 3 is a schematic cross-sectional view showing an adhesive layer which is an example of a shape of a concave portion. Fig. 4 is a cross-sectional view schematically showing a method of peeling off an adhesive sheet according to an embodiment of the present invention. Fig. 5 is an image (a) obtained by using an embossed surface of the embossed film (1) produced in Example 1 using a digital microscope, and an image (b) obtained by binarizing the image. Fig. 6 is an image (a) obtained by photographing an embossed surface of the embossed film (2) produced in Example 2 using a digital microscope, and an image (b) obtained by binarizing the embossed surface. Fig. 7 is an image (a) obtained by using an embossed surface of the embossed film (3) produced in Example 3 using a digital microscope, and an image (b) obtained by binarizing the embossed surface. Fig. 8 is an image (a) obtained by attaching an adhesive surface of an adhesive sheet produced in Example 1 to a glass plate and using a digital microscope through a glass, and an image (b) obtained by binarization. Fig. 9 is an image (a) obtained by attaching an adhesive surface of an adhesive sheet manufactured in Example 2 to a glass plate and using a digital microscope through a glass, and an image (b) obtained by binarization. Fig. 10 is an image (a) obtained by attaching an adhesive surface of an adhesive sheet produced in Example 3 to a glass plate and using a digital microscope through a glass, and an image (b) obtained by binarization.

Claims (11)

A method for peeling an adhesive sheet, which is a method for peeling an adhesive sheet having at least an adhesive layer and an adhesive sheet peeled off from an adhesive surface adhered to an adhesive surface of the adhesive layer, characterized in that: the adhesive layer The adhesive surface has a concave portion, and the adherend is adhered to the adhesive sheet so as to form an independent space by the concave portion of the adhesive layer, and the adhesive is adhered to at least the adhesive. The sheet is subjected to a pressure reduction treatment for expanding the gas in the space to lower the adhesion of the pressure-sensitive adhesive layer, thereby peeling off the pressure-sensitive adhesive sheet from the adherend. The method of peeling an adhesive sheet according to claim 1, wherein the pressure reduction treatment is lower than an environmental pressure of attaching the adhesive sheet to an environment of the adherend. The method of peeling an adhesive sheet according to claim 1, wherein the adhesive composition forming the pressure-sensitive adhesive layer has no active energy ray hardening property and thermosetting property. The method of peeling an adhesive sheet according to claim 3, wherein the adhesive composition contains a (meth) acrylate polymer. The method of peeling an adhesive sheet according to claim 1, wherein the adhesive composition forming the adhesive layer has active energy ray hardening property or thermosetting property. The method for peeling an adhesive sheet according to claim 5, wherein the active energy ray-curable adhesive composition contains a (meth) acrylate polymer having an active energy ray-curable group in a side chain. The method for peeling an adhesive sheet according to claim 5, wherein the pressure-sensitive adhesive layer is irradiated with an energy ray to cure the pressure-sensitive adhesive layer, and then the pressure-reducing treatment is performed. The method for peeling an adhesive sheet according to claim 5, wherein after the pressure reduction treatment, the adhesive layer is irradiated with an energy ray to cure the adhesive layer. The method of peeling an adhesive sheet according to claim 1, wherein the adhesive sheet is used for temporary fixation of the adherend. The method of peeling an adhesive sheet according to claim 9, wherein the adherend is an electronic member or an optical member. A method for producing a processed article, which is a method for producing a processed article, which comprises the steps of: forming a workpiece, and an adhesive sheet having a concave portion on an adhesive surface of at least the adhesive layer and having the adhesive layer; a step of adhering the concave portion of the adhesive surface to the workpiece to form a separate space; a step of processing the workpiece adhered to the adhesive sheet into a processed object; and adhering at least the foregoing The pressure-sensitive adhesive sheet of the processed material is placed in a pressure-reducing environment in which the gas in the space is expanded in a reduced pressure environment, and the adhesive force of the pressure-sensitive adhesive layer is lowered, and the workpiece is peeled off from the pressure-sensitive adhesive sheet.