TWI808302B - Adhesive sheet and its utilization - Google Patents

Abstract

The present invention provides a novel adhesive sheet suitable for simultaneous inspection of a whole batch of a plurality of conductive small pieces. The invention provides an adhesive sheet with an adhesive layer. The surface resistance value of the aforementioned adhesive layer is 1.0×10 ⁸ Ω/□ or less. Also, the adhesion force of the adhesive sheet to the stainless steel plate is within the range of 0.01 to 4.0N/20mm.

Description

Adhesive sheet and its utilization

The present invention relates to adhesive sheets and their utilization. This application claims priority based on Japanese Patent Application No. 2019-020095 filed on February 6, 2019, and the entire content of the application is incorporated herein by reference.

Background technique In general, adhesives (also called pressure-sensitive adhesives, hereinafter the same) are in a soft solid (viscoelastic) state in a temperature range around room temperature, and have the property of easily bonding to an adherend by pressure. Adhesives are widely used in various fields in the form of a support-attached adhesive sheet having an adhesive layer on a support, or a support-free adhesive sheet that does not have a support, due to the fact that it has good adhesion workability to an adherend. Such an adhesive can be removed from the adherend after being adhered to the adherend and fulfilling its bonding purpose. Patent Documents 1 and 2 are cited as prior art documents disclosing such a prior art. Patent Documents 1 and 2 relate to surface protection films used to temporarily protect polarizers attached to liquid crystal cells when manufacturing liquid crystal display panels, and disclose adhesives with antistatic properties. Prior art literature patent documents

Patent Document 1: Specification of Japanese Patent No. 5061898 Patent Document 2: Specification of Japanese Patent No. 5535987

Summary of the invention The problem to be solved by the invention However, the output of various semiconductor components used in electronic products with display functions is increasing year by year, and due to the demand for miniaturization and high performance of products, the components are also progressing towards miniaturization. Therefore, there is a problem that the inspection performance of components and the time required for inspection increase. Specifically, in order to ensure the quality of semiconductor wafers such as light emitting diodes, all of the plurality of wafers formed in the manufacturing process are electrically inspected. In this inspection, the probes are brought into direct contact with the electrodes of each chip and then energized to determine defective products, classify chips, and the like. However, due to the miniaturization of the above-mentioned chip, the electrode area is also reduced, and it becomes difficult to make the probes contact the tiny electrodes correctly. Also, as mentioned above, since the inspection is carried out in units of wafers, compared with the miniaturization of wafers that can be implemented in units of wafers (generally, the miniaturization of wafers using a dicing step or a wafer expansion step), the time required for inspection due to wafer miniaturization increases significantly.

The present inventors have come up with a novel solution different from the previous ones for the above technical limitations and reduction in productivity. The idea is to fix a plurality of conductive small pieces (such as semiconductor wafers) with a conductive adhesive, make the electrodes of the conductive small pieces contact the adhesive at the same time, and let the current flow through each conductive small piece through the adhesive, thereby checking all the conductive small pieces on the adhesive simultaneously and in batches. Based on the above idea, research was carried out on the realization of a structure suitable for simultaneously inspecting a batch of a plurality of conductive small pieces, and as a result, the present invention was finally completed. That is, an object of the present invention is to provide a novel adhesive sheet suitable for simultaneous inspection of a whole batch of a plurality of conductive small chips. Another object of the present invention is to provide a manufacturing method for inspecting completed conductive chips. means to solve problems

According to this specification, the adhesive sheet provided with the adhesive layer is provided. The surface resistance value of the aforementioned adhesive layer is 1.0×10 ⁸ Ω/□ or less. Also, the adhesive force of the adhesive sheet to the stainless steel plate is within the range of 0.01-4.0N/20mm.

The adhesive sheet with the above-mentioned structure has a conductivity higher than the specified limit, so by fixing a plurality of conductive small pieces (such as semiconductor wafers) on the adhesive layer, the plurality of conductive small pieces arranged on the adhesive can be energized in batches at the same time through the adhesive layer. In addition, by setting the adhesive force of the adhesive sheet within a predetermined range, the conductive small pieces can be reliably fixed, and the conductive small pieces can be well separated from the surface of the adhesive layer after the energization step is completed.

In some preferred aspects, the haze value of the adhesive sheet is 50% or less. Depending on the adhesive sheet whose haze value is limited to a specified value or less, the inspection of the adhered body fixed to the adhesive sheet can be carried out through the adhesive sheet.

In some preferred aspects, the aforementioned adhesive layer includes oxyalkylene structural units. According to the adhesive layer comprising the oxyalkylene group structural unit, it is easy to obtain good electrical conductivity, and it is also easy to achieve both electrical conductivity and transparency.

In some aspects, the aforementioned adhesive layer preferably includes a polymer having the aforementioned oxyalkylene structural unit. By using a polymer having an oxyalkylene group structural unit, an adhesive layer having good electrical conductivity and having both bonding reliability and adherend separation and removability can be preferably obtained. In some aspects, the polymer having the aforementioned oxyalkylene structural unit has the aforementioned oxyalkylene structural unit in a side chain. By providing an oxyalkylene group structural unit to a side chain having a higher degree of freedom of movement than the polymer main chain, higher conductivity is easily obtained based on its degree of freedom.

In some preferable aspects, the content rate of the said oxyalkylene group structural unit in the said adhesive agent layer is 20-95 weight%. By making the adhesive layer contain a specific amount of oxyalkylene structural units, it is easy to obtain higher conductivity, and it is easy to have both bonding reliability and adherend separation and removal.

In some preferred aspects, the aforementioned adhesive layer contains ionic compounds. By including the ionic compound, the adhesive layer can preferably exhibit high conductivity. Also, the use of ionic compounds is ideal for maintaining the transparency of the adhesive layer. Furthermore, compared with metal particles, it is also very advantageous in that the thickness of the adhesive layer can be reduced.

The adhesive sheet in some preferred aspects further has a substrate layer. Moreover, the aforementioned adhesive layer is disposed on at least one side (for example, one side) of the base material layer. The adhesive sheet provided with the base material layer can be excellent in processability and handleability because of its specific rigidity. In a more preferable aspect, the aforementioned base material layer is composed of a resin film with an elastic modulus of 50 MPa or more.

In some preferred aspects, a primer layer is disposed between the aforementioned base material layer and the aforementioned adhesive layer. By setting the primer layer, the anchoring property of the adhesive layer can be improved, and it can better prevent the adhesive residue from being left on the adherend when peeling off.

Moreover, according to this specification, there is provided a manufacturing method for inspecting a completed conductive small piece (such as a semiconductor wafer). The method comprises the following steps: preparing an adhesive sheet on which a plurality of conductive small pieces of the inspection object are fixed, wherein the adhesive sheet has a conductive adhesive layer, and the plurality of conductive small pieces of the inspection object are detachably fixed on the surface of the adhesive layer; and electrifying at least a part of the plurality of conductive small pieces of the inspection object through the adhesive layer, and checking the electrified state of the conductive small pieces of the inspection object. According to the above-mentioned method, it is possible to carry out the simultaneous electrification inspection of the whole batch of a plurality of conductive small pieces. Generally, before the inspection step, the above-mentioned method may further include the step of making the surfaces of the plurality of conductive small pieces to be inspected, which are opposite to the fixed surface of the adhesive layer, contact the conductive material. In the above method, in the inspection step, the conductive small piece of the inspection object is energized through the adhesive layer and the conductive material. Moreover, the above-mentioned manufacturing method of the inspected conductive small piece may be an inspection method of the conductive small piece (such as a semiconductor wafer).

Also, in some aspects of the above method, before the step of preparing the adhesive sheet on which the conductive small piece (such as a semiconductor chip) is fixed, the following steps may be included: a step of fixing the conductive wafer on the adhesive sheet; and a step of processing the conductive wafer to form the plurality of conductive small pieces from the conductive wafer. The processing step of the conductive wafer may include the step of dicing the conductive wafer and the step of expanding the wafer. In some other aspects, before the step of preparing the adhesive sheet on which the conductive small pieces are fixed, the following step may be included: a step of fixing a plurality of conductive small pieces formed by using different adhesive sheets or using different methods to the adhesive sheet. The adhesive sheet used in the above method is preferably the adhesive sheet disclosed in this case. Also, the conductive material used in the above method is preferably the adhesive sheet disclosed in this case, or a metal plate, or a well-known or even commonly used conductive adhesive sheet can be used. In some aspects, the step of inspecting the conductive small pieces of the inspected object may include inspecting using inspection mechanisms such as cameras or visually inspecting through the adhesive sheet (such as inspecting the luminous intensity or light wavelength of light-emitting semiconductor elements).

form for carrying out the invention Hereinafter, preferred embodiments of the present invention will be described. Also, matters other than those specifically mentioned in this specification and necessary for implementing the present invention can be understood by those skilled in the art based on the teachings on implementation of the invention described in this specification and the technical common sense at the time of filing. The present invention can be implemented based on the contents disclosed in this specification and common technical knowledge in this field. In addition, in the following drawings, members and parts that perform the same functions may be given the same symbols and described, and overlapping descriptions may be omitted or simplified. In addition, the embodiments described in the drawings are schematic for clearly explaining the present invention, and do not necessarily represent the dimensions and scales of products actually provided accurately.

In this specification, the term "adhesive" refers to a material that exhibits a soft solid (viscoelastic) state in a temperature range around room temperature and has the property of being easily adhered to an adherend by pressure, as described above. The so-called adhesive in this case is defined in "CA Dahlquist, "Adhesion: Fundamental and Practice", McLaren & Sons, (1966) P. 143", and generally can be a material that satisfies the property of the complex tensile elastic modulus E ^* (1Hz)<10 ⁷ dyne/cm ² (usually a material with the above properties at 25°C).

＜Constitution Example of Adhesive Sheet＞ The adhesive sheet disclosed in this case may be an adhesive sheet with a substrate in the form of having the above-mentioned adhesive layer on one or both sides of a non-release substrate (support substrate), or an adhesive sheet without a substrate (that is, an adhesive sheet without a non-release substrate) in a form in which the adhesive layer is held on a release liner. The concept of the so-called adhesive sheet in this case may include what is called an adhesive tape, an adhesive label, an adhesive film, and the like. In addition, the adhesive sheet disclosed in this case may be in the form of a roll or a single sheet. Alternatively, it may be an adhesive sheet that is further processed into various shapes.

Fig. 1 shows a configuration example of the adhesive sheet disclosed in this case. This adhesive sheet 1 includes a base material layer 10 and an adhesive layer 20 . The adhesive layer 20 is provided on one surface (first surface) 10A of the base material layer 10 . Details will be described later, but the adhesive layer 20 has conductivity. The surface (adhesive surface) 20A of the adhesive layer 20 has a structure in which at least the adhesive layer side is protected by a release liner (not shown) serving as a release surface. Alternatively, the other side 10B of the base material layer 10 is a peeling side, and if the adhesive layer 20 is in contact with the other side 10B by winding the adhesive sheet 1, the adhesive side 20A can also be protected by the other side 10B of the base material layer.

Fig. 2 is another configuration example of a single-sided adhesive sheet. The adhesive sheet 2 shown in FIG. 2 includes a base layer 10 and an adhesive layer 20 , and further includes a primer layer 30 between the base layer 10 and the adhesive layer 20 . Specifically, one surface 30B of the primer layer 30 is in contact with the base material layer 10 , and the other surface (the surface opposite to the one surface) 30A of the primer layer 30 is in close contact with the adhesive layer 20 . By having such an undercoat layer 30, the anchoring property of the adhesive layer 20 can be improved, and adhesive residue can be prevented from occurring when it is separated and removed from the adherend. Details will be described later, but the undercoat layer 30 may be conductive.

<Adhesive Layer> (Surface Resistance Value) In general aspects, the adhesive layer of the adhesive sheet disclosed in this application is characterized in that its surface resistance value is 1.0×10 ⁸ Ω/□ or less (for example, less than 1.0×10 ⁸ Ω/□). The adhesive layer whose surface resistance value is limited to below the specified value can have good electrical conductivity, and the adherend can be energized through the adhesive layer. From the viewpoint of conductivity suitable for the conduction of the bonded body, the above-mentioned surface resistance value is preferably 1.0×10 ⁷ Ω/□ or less (for example, less than 1.0×10 ^{7 Ω/□), preferably 1.0×10 6 Ω} /□ or less (for example, less than 1.0×10 ⁶ Ω/□), more preferably 5.0×10 ^{5 Ω/□ or less, still more preferably 1.0×10 5} Ω/□ or less (for example, 5.0×10 5 Ω/□ or less .0× ^{10 4 Ω} /□ or less). The lower limit of the above-mentioned surface resistance value is not particularly limited, and it is generally 1.0×10 ² Ω/□ or more, and may be 1.0×10 ³ Ω/□ or more (for example, 1.0×10 ⁴ Ω/□ or more). The surface resistance value of the adhesive layer can be measured by the method described in the examples described later. Furthermore, the adhesive sheet disclosed in this specification includes an aspect in which the surface resistance value of the above-mentioned adhesive layer is not limited, and in this aspect, the adhesive layer is not limited to those having the above-mentioned surface resistance value.

(haze value) The haze value of the adhesive layer is not particularly limited, and may be, for example, about 80% or less. When inspecting the adherend through the adhesive sheet, the adhesive layer needs moderate penetration. From the above point of view, the haze value of the adhesive layer is preferably about 50% or less (for example, about 30% or less), preferably about 10% or less, more preferably about 3% or less, and more preferably about 1% or less (for example, less than 0.1%). The haze value can be measured by the method described in the Examples described later.

(Oxyalkylene Structural Unit) In some preferred aspects, the adhesive layer (it can also be an adhesive composition, the same below unless otherwise specified) includes an oxyalkylene structure unit. According to the adhesive layer comprising the oxyalkylene group structural unit, it is easy to obtain good electrical conductivity, and it is also easy to achieve both electrical conductivity and transparency. Regarding the aspect of the adhesive layer containing the oxyalkylene structural unit, it is possible to use a polymer or oligomer having an oxyalkylene structural unit, any one of other additives, or a plurality of combinations thereof, among which it is preferable to use a polymer having an oxyalkylene structural unit. By using this polymer as the main component (base polymer) in the adhesive, the oxyalkylene structural unit can be contained at a predetermined content rate in the entire system.

The oxyalkylene structural units included in the adhesive layer can be defined as (poly)oxyalkylene units. The (poly)oxyalkylene unit includes a unit composed of (poly)oxyethylene or (poly)oxypropylene, which can generally be obtained by addition of ethylene oxide, propylene oxide, or addition of polyalkylene glycol such as polyethylene glycol. The oxyalkylene structural units preferably comprise polyoxyethylene units.

The molar number of (poly)oxyalkylene units in the oxyalkylene structural unit (also called addition molar number, generally the repeating number of oxyalkylene groups) is usually 1 or 2 or more. From the viewpoint of improving the mobility (electron conductivity) of electrons (which may be in the form of ions) in the adhesive layer, the molar number of the above-mentioned (poly)oxyalkylene units is preferably greater than 2, preferably 3 or greater, more preferably 5 or greater, even more preferably 7 or greater (for example, 8 or greater). The upper limit of the molar number of the above-mentioned (poly)alkylene oxyalkylene unit is not particularly limited, but it is preferably less than 30, preferably less than 20, for example, 15 or less, 13 or less, and 11 or less (generally 10 or less) from the viewpoint of the synthesis (ease of polymerization) and operability of polymers having oxyalkylene structural units. In the aspect of using a polymer, oligomer, etc. having an oxyalkylene structural unit, the molar number of (poly)oxyalkylene units in the oxyalkylene structural unit of the polymer, oligomer, etc. can also be selected from the above range.

The content ratio of the oxyalkylene group structural unit in the adhesive layer (may also be the solid content of the adhesive composition) is set according to the electrical conductivity to the adherend, etc., and therefore is not limited to a specific range. The content ratio of the oxyalkylene structural unit in the adhesive layer is, for example, about 5% by weight or more, preferably about 10% by weight or more, preferably about 20% by weight or more, more preferably about 30% by weight or more, still more preferably about 40% by weight or more, particularly preferably about 50% by weight or more (for example, about 60% by weight or more) from the viewpoint of improving electrical conductivity. In consideration of adhesion reliability, separation and removal of the adherend, etc., the upper limit of the content ratio of the oxyalkylene group structural unit in the adhesive layer is preferably set at about 95% by weight or less, such as about 85% by weight or less, about 75% by weight or less, or about 65% by weight or less (for example, about 55% by weight or less).

(polymer) In the technology disclosed in this case, the type of adhesive constituting the adhesive layer is not particularly limited. The above-mentioned adhesive (or an adhesive composition) may be one or more of various rubbery polymers such as acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluorine polymers known in the adhesive field. From the viewpoint of adhesive performance, cost, etc., acrylic polymers and urethane polymers are preferably used. Among them, an adhesive mainly composed of an acrylic polymer (acrylic adhesive) is preferable.

The term "acrylic polymer" refers to a polymer including a monomer unit derived from a monomer having at least one (meth)acryl group in one molecule as a monomer unit constituting the polymer. Hereinafter, a monomer having at least one (meth)acryl group in one molecule is also referred to as an "acrylic monomer". Therefore, the acrylic polymer in this specification is defined as a polymer comprising a monomer unit derived from an acrylic monomer. Typical examples of acrylic polymers include acrylic polymers in which the ratio of acrylic monomers in all monomer components used to synthesize the acrylic polymer exceeds 50% by weight. In addition, the term "(meth)acryloyl (meta) acryloyl group" means to include acryloyl and methacryloyl. Similarly, "(meth)acrylate" means including acrylate and methacrylate, and "(meth)acryl group" means including acryl group and methacryl group.

The so-called "urethane-based polymer" refers to a polymer that contains polyol and polyfunctional isocyanate as units constituting the polymer, and the hydroxyl group of the polyol and the isocyanate group of the polyfunctional isocyanate are polymerized through a urethane bond (complex addition). Polyols and polyfunctional isocyanates before the reaction generally exist in the form of monomers or oligomers (hereinafter sometimes collectively referred to as "monomers"). Urethane polymers obtained by the above reactions generally have a structure in which segments from polyols and segments from polyfunctional isocyanates repeat alternately. In addition, the above-mentioned monomer includes what is called a so-called macromonomer. Also, the term "oligomer" in this specification refers to a polymer with a molecular weight of less than 3.0×10 ⁴ . As for the molecular weight of the oligomer, the weight average molecular weight (Mw) converted to standard polystyrene obtained by gel permeation chromatography (GPC) or the molecular weight calculated from the chemical formula was used.

(Polymers with oxyalkylene structural units) In some preferred aspects, the adhesive layer (or adhesive composition) includes a polymer containing oxyalkylene structural units. Thereby, good electrical conductivity can be easily obtained. The polymer containing an oxyalkylene structural unit may have an oxyalkylene structural unit in its main chain or side chain. The oxyalkylene structural unit may also be incorporated in the structure of the polymer (eg, in the network structure). Among them, it is preferably used for a polymer having an oxyalkylene structural unit in a side chain. By arranging the oxyalkylene structural unit in the side chain, it is easy to obtain higher conductivity due to its high degree of freedom. In the configuration in which the side chain of the polymer has an oxyalkylene structural unit, there is no particular limitation as long as the chemical structure of the side chain has an oxyalkylene structural unit. The polymer side chain may be in the form of (poly)oxyalkylene monoalcohol or (poly)oxyalkylene monoalkyl ether, for example. The form of the side chain terminal is not particularly limited, and may be an alkyl group such as a methyl group, a phenyl group, etc., or a functional group such as a hydroxyl group.

Since the content of the oxyalkylene structural unit in the polymer containing an oxyalkylene structural unit is set according to the electrical conductivity to an adherend, etc., it is not limited to a specific range. The ratio of the oxyalkylene structural unit in the polymer can be, for example, about 10% by weight or more. From the viewpoint of improving electrical conductivity, it is preferably about 25% by weight or more, preferably about 35% by weight or more, more preferably about 45% by weight or more, still more preferably about 55% by weight or more, and most preferably about 65% by weight or more (for example, about 70% by weight or more). The upper limit of the ratio of the oxyalkylene structural unit in the polymer is not particularly limited in consideration of the reliability of bonding and the separation and removal of the adherend, etc., but it is preferably set to be less than about 95% by weight, for example, it can be less than about 90% by weight, it can be less than about 85% by weight, it can be less than about 75% by weight (for example, less than about 70% by weight).

A polymer containing an oxyalkylene structural unit can be obtained by polymerizing a monomer having an oxyalkylene structural unit. The polymerization method is not particularly limited, and may be radical polymerization, ion polymerization, polycondensation, complex addition, or the like. Alternatively, a polymer having an oxyalkylene structural unit can also be obtained, for example, by adding an oxyalkylene structural unit to the polymer. For example, a method of adding a compound having an oxyalkylene structural unit such as polyethylene glycol (PEG) to a polymer obtained by a general method is known or conventionally used. According to the above method, a polymer having an oxyalkylene structural unit in a side chain can be preferably obtained.

In some aspects, the monomer having an oxyalkylene structural unit is a compound having a polymerizable reactive group such as a vinyl group or a (meth)acryl group and an oxyalkylene structural unit. For example, an acrylic monomer having an oxyalkylene structural unit, a vinyl ether monomer having an oxyalkylene structural unit, or a polycarboxylic acid monomer having an oxyalkylene structural unit (for example, a compound containing an oxyalkylene structural unit such as PEG added to maleic anhydride or the like (for example, esterified)). From the viewpoint of polymerizability and the like, it is preferable to use an acrylic monomer having an oxyalkylene structural unit.

(Acrylic polymer with oxyalkylene structural unit) In some preferred aspects, the polymer containing oxyalkylene structural units is an acrylic polymer having oxyalkylene structural units. Hereinafter, preferred examples will be described centering on acrylic polymers containing oxyalkylene structural units, but the polymers containing oxyalkylene structural units disclosed in this application are not intended to be limited to acrylic polymers.

The above-mentioned acrylic polymer containing an oxyalkylene structural unit can be preferably obtained by polymerizing an acrylic monomer having an oxyalkylene structural unit. As for the acrylic monomer containing an oxyalkylene group structural unit, one or more of acrylic monomers containing (poly)oxyethylene units, acrylic monomers containing (poly)oxypropylene units, and acrylic monomers having (poly)oxyethylene units and (poly)oxypropylene units can be used.

Acrylic monomers containing (poly)oxyethylene units include alkoxy (poly)ethylene glycol (meth)acrylates such as methoxypolyethylene glycol (meth)acrylate and ethoxypolyethylene glycol (meth)acrylate; (poly)ethylene glycol (meth)acrylates such as polyethylene glycol (meth)acrylate. Acrylic monomers containing (poly)oxypropylene units include alkoxy (poly)propylene glycol (meth)acrylates such as methoxy polypropylene glycol (meth)acrylate and ethoxy polypropylene glycol (meth)acrylate; (poly)propylene glycol (meth)acrylates such as polypropylene glycol (meth)acrylate. These can be used individually by 1 type or in combination of 2 or more types. Among them, an acrylic monomer containing a (poly)oxyethylene unit is preferably used from the viewpoint of electron conductivity. In the above-mentioned monomers, the terminal on the side of the oxyalkylene structural unit may be an alkyl group such as a methyl group, a phenyl group, etc., or a functional group such as a hydroxyl group. The terminal structure of the monomer can be appropriately set in consideration of crosslinking reaction and the like.

The usage amount of the monomer containing the oxyalkylene structural unit (preferably the acrylic monomer containing the oxyalkylene structural unit) is set according to the electrical conductivity and adhesive properties to the adherend, so it is not limited to a specific range. The usage amount of the monomer of the oxyalkylene-containing structural unit can be set at about 10 mol% or more (for example, 30 mol% or more) of the total amount of monomers used to synthesize the polymer of the oxyalkylene-containing structural unit (hereinafter also referred to as "total monomer components"). From the viewpoint of improving electrical conductivity, the amount of monomers containing oxyalkylene-containing structural units in the total amount of monomers should be set at about 30 mol% or more, preferably about 45 mol% or more, more preferably about 55 mol% or more, more preferably about 65 mol% or more, and most preferably about 75 mol% or more (for example, about 80 mol% or more). In addition, from the viewpoint of cohesiveness and adhesive force, the usage amount of the monomer of the oxyalkylene-containing structural unit in the total amount of monomers is preferably not more than about 95 mol%, preferably not more than about 90 mol%, may be not more than about 80 mol%, may be not more than about 70 mol%, may be not more than about 60 mol% (for example, not more than about 50 mol%).

As for the polymer of the oxyalkylene-containing structural unit in the technology disclosed in this case, it is preferable to use a monomer having a hydroxyl group (-OH) copolymerized. Specific examples of hydroxyl-containing monomers include hydroxyl-containing acrylic monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. These hydroxyl group-containing monomers may be used alone or in combination of two or more. A polymer obtained by copolymerization of the monomer is preferable because it is easy to obtain an adhesive that can both adhere and fix and separate and remove the adherend. For example, since it is easy to control the peeling force from the adherend to be low, it is easy to obtain an adhesive having excellent separation and removability of the adherend. Also, since the shorter the side chain containing the hydroxyl group in the polymer, the easier it is to obtain the effect of improving the cohesive force, so it is preferable to use a hydroxyl group-containing monomer with a shorter distance from the polymerizable reactive group (generally (meth)acryl group) of the above-mentioned hydroxyl group-containing monomer to the hydroxyl group (in the case of hydroxyl (meth)acrylate, it is a monomer with a smaller number of carbon atoms in the hydroxyalkyl group).

From the perspective of fully exerting the use effect of the monomer, the hydroxyl-containing monomer is preferably used in a ratio of more than about 1 mol% of the total monomers used to synthesize the polymer containing the oxyalkylene-containing structural unit, preferably at least about 3 mol%, more preferably at least about 5 mol%, even more preferably at least about 8 mol%, and can also be at least about 12 mol% (or more than about 15 mol%). In addition, considering the cohesiveness and adhesive force of the adhesive, in the total amount of monomers used to synthesize the above polymer, the amount of hydroxyl-containing monomers is preferably less than about 40 mol%, preferably less than about 30 mol%, more preferably less than about 20 mol%.

In some preferred aspects, the polymer containing the oxyalkylene structural unit comprises a monomer (high Tg monomer) whose Tg (glass transition temperature) of the homopolymer is about 10° C. or higher as a monomer unit. By copolymerizing high Tg monomers, the cohesiveness of the adhesive can be improved and the adhesive force can be improved. Also, there is a tendency to improve separation and removal properties for preventing adhesive residue and the like. From the viewpoint of improving coagulation, in some preferred aspects, the Tg of the homopolymer of the high Tg monomer is preferably about 30°C or higher (for example, about 50°C or higher), or about 70°C or higher, or about 90°C or higher. Also, the upper limit of the Tg of the homopolymer of the high Tg monomer is not particularly limited, but it is generally preferably about 200°C or lower from the viewpoint of the ease of synthesis of the polymer. In some aspects, the Tg of the homopolymer of the high Tg monomer can be about 180°C or lower, about 150°C or lower, or about 120°C or lower.

High Tg monomers are exemplified as monomers that can be used for synthesizing polymers of oxyalkylene-containing structural units, and those having a specified or higher homopolymer Tg can be used without particular limitation. For example, one or more monomers selected from other monomers such as alkyl (meth)acrylates and various functional group-containing monomers exemplified below can be used. Among them, alkyl (meth)acrylates are preferred, and among them, alkyl methacrylates (generally methyl methacrylates) in which the number of carbon atoms in the alkyl group ranges from 1 to 4 can be used.

The high Tg monomer can be set to a ratio of about 1 mol% or more in the total amount of monomers used to synthesize the polymer containing an oxyalkylene-containing structural unit. From the viewpoint of improving the cohesiveness of the adhesive and improving the adhesive force, it is preferably about 5 mol% or more, preferably about 10 mol% or more, more preferably about 15 mol% or more, and may be about 25 mol% or more (for example, about 35 mol% or more). Also, considering the adhesive force, in the total amount of monomers used to synthesize the above polymer, the amount of the high Tg monomer is preferably less than about 60 mol%, preferably less than about 50 mol%, more preferably less than about 40 mol% (for example, less than about 30 mol%). In some other aspects, the high Tg monomer may account for less than 10 mol% or less than 1 mol% of the total amount of monomers mentioned above. The polymer containing an oxyalkylene structural unit may also substantially not contain a high Tg monomer as a monomer unit.

The polymer containing the oxyalkylene structural unit disclosed in this case may also include an alkyl (meth)acrylate as a monomer unit. The alkyl group which this alkyl (meth)acrylate has may be a chain alkyl group or an alicyclic alkyl group. Regarding the number of carbon atoms in the alkyl group, those in the range of 1 to 20 can be used. Specific examples of the alkyl (meth)acrylate include ethyl (meth)acrylate, butyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, and the like.

From the viewpoint of cohesiveness and adhesion, the amount of alkyl (meth)acrylate (for example, alkyl (meth)acrylate not corresponding to the above-mentioned high Tg monomer) can be set at about 30 mol% or less, for example, about 10 mol% or less, or about 1 mol% or less in the total amount of monomers used to synthesize the polymer of the oxygen-containing alkylene structural unit. The polymer containing an oxyalkylene structural unit may also substantially not contain an alkyl (meth)acrylate (for example, an alkyl (meth)acrylate that does not correspond to the above-mentioned high Tg monomer) as a monomer unit.

In the polymer of the oxyalkylene-containing structural unit disclosed in this application, monomers other than the monomer of the oxyalkylene-containing structural unit and the hydroxyl-containing monomer (other monomers) can also be copolymerized. This monomer can be used for the purpose of adjusting adhesive performance (for example, separation and removal property of an adherend), etc., for example. For example, monomers that can improve the cohesive force and heat resistance of adhesives include sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl esters such as vinyl acetate, and aromatic vinyl compounds such as styrene. Also, the introduction of a functional group that can become a crosslinking point into an acrylic polymer or a monomer (functional group-containing monomer) that can contribute to an improvement in adhesive force includes: carboxyl group-containing monomers such as acrylic acid and methacrylic acid; acid anhydride group-containing monomers such as maleic anhydride; amide-group-containing monomers such as acrylamide; amine-group-containing monomers; Cyclic monomers; vinyl ethers, etc. Furthermore, regarding other monomers, for the purpose of crosslinking treatment, etc., a polyfunctional monomer can be used as a copolymerizable component. As the polyfunctional monomer, one or two or more types of hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate can be used. These other monomers may be used alone or in combination of two or more.

From the viewpoint of making full use of the characteristics of the monomers of the oxyalkylene-containing structural unit, the usage amount of the above-mentioned other monomers can be set to be about 30 mol% or less, for example, about 10 mol% or less, or about 1 mol% or less of the total amount of monomers used to synthesize the polymer of the oxyalkylene-containing structural unit. The polymer containing an oxyalkylene group structural unit may not substantially contain the above-mentioned other monomers as monomer units.

The method for obtaining a polymer containing an oxyalkylene group structural unit is not particularly limited, and various polymerization methods known as a synthesis method of a polymer (such as an acrylic polymer) such as a solution polymerization method, an emulsion polymerization method, a block polymerization method, a suspension polymerization method, and a photopolymerization method can be suitably used. For example, a solution polymerization method can be preferably employed. The polymerization temperature during solution polymerization can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc., for example, it can be set at about 20°C to 170°C (generally about 40°C to 140°C). In addition, the aforementioned polymer may be a random copolymer, or may be a block copolymer or a graft copolymer. From the standpoint of productivity and the like, a random copolymer is generally preferable.

The solvent used for solution polymerization (polymerization solvent) can be appropriately selected from known organic solvents. For example, any one solvent or a mixed solvent of two or more selected from the following can be used: aromatic compounds such as toluene (generally aromatic hydrocarbons); acetates such as ethyl acetate; aliphatic or alicyclic hydrocarbons such as hexane or cyclohexane; halogenated alkanes such as 1,2-dichloroethane; lower alcohols such as isopropanol (such as monohydric alcohols with 1 to 4 carbon atoms);

The initiator used for polymerization can be appropriately selected from known polymerization initiators according to the type of polymerization method. For example, one or two or more types of azo-based polymerization initiators such as 2,2'-azobisisobutyronitrile (AIBN) can be preferably used. Other examples of the polymerization initiator include persulfates such as potassium persulfate; peroxide initiators such as benzoyl peroxide and hydrogen peroxide; substituted ethane initiators such as phenyl substituted ethane; and aromatic carbonyl compounds. As yet another example of the polymerization initiator, a redox system initiator using a combination of a peroxide and a reducing agent may be mentioned. Such a polymerization initiator can be used individually by 1 type or in combination of 2 or more types. The usage-amount of a polymerization initiator should just be a general usage-amount, For example, it can select from the range of about 0.005-1 weight part (generally about 0.01-1 weight part) with respect to 100 weight part of monomer components.

The polymer of the oxyalkylene-containing structural unit disclosed in this case preferably has a weight-average molecular weight (Mw) of about 3×10 ⁴ or more in terms of standard polystyrene as obtained by GPC (gel permeation chromatography), and is preferably about 10×10 ⁴ or more, more preferably about 20×10 ⁴ or more, and even more preferably about 30×10 ^{4 or} more from the viewpoint of separation and removal of the adherend. In addition, the upper limit of the above-mentioned Mw is not particularly limited, for example, it is preferably about 500×10 ⁴ or less, and from the viewpoint of adhesive force and coatability when forming an adhesive layer, etc., it is preferably about 100×10 ⁴ or less, more preferably about 70×10 ⁴ or less, and may be about 50×10 ⁴ or less.

The dispersion (Mw/Mn) of the polymer containing oxyalkylene structural units disclosed in this application is not particularly limited. The degree of dispersion (Mw/Mn) here refers to the degree of dispersion (Mw/Mn) expressed by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). In a preferred aspect, the dispersity (Mw/Mn) of the polymer of the oxyalkylene-containing structural unit is preferably about 15 or less, preferably about 10 or less, more preferably about 7 or less from the viewpoint that a relatively uniform high molecular weight body can better exhibit aggregation. In addition, the above-mentioned Mw/Mn is 1 or more theoretically, and may be, for example, 2 or more, 3 or more, or 4 or more (generally 5 or more).

Specifically, the above-mentioned Mw and Mn can be measured under the following conditions using a GPC measuring device under the trade name "HLC-8120GPC" (manufactured by Tosoh Corporation). [GPC measurement conditions] Sample concentration: 0.2% by weight (tetrahydrofuran solution) Sample injection volume: 100 μL Eluent: tetrahydrofuran (THF) Flow rate (flow rate): 0.8 mL/column temperature (measurement temperature): 40°C Column: Tosoh Corporation, G7000H _XL + GMH _XL + GMH _XL column size: each 7.8mmφ×30cm Total 90cm detector : Differential refractometer (RI) Standard sample: Polystyrene

(Urethane-based polymer having an oxyalkylene structural unit) In some aspects, the adhesive layer may include a urethane-based polymer having an oxyalkylene structural unit. Urethane-based polymers containing an oxyalkylene structural unit generally have an oxyalkylene structural unit in the main chain skeleton, and in some aspects (such as a composition in which polyhydric alcohol is added in excess of polyfunctional isocyanate) may also have an oxyalkylene structural unit in the side chain. The oxyalkylene structural unit can be derived from any of the polyol and polyfunctional isocyanate constituting the urethane polymer. From the perspective of the ease of introduction into the polymer structure, the oxyalkylene structural unit can be introduced into the urethane polymer by using a polyol having an oxyalkylene structural unit.

About the polyhydric alcohol used for forming the said urethane type polymer, 1 type or 2 or more types of appropriate compounds can be selected from the compound which has several hydroxyl groups. For example, one type or two or more types of polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, castor oil polyol, etc. can be used. Among them, polyester polyol and polyether polyol are preferably used, more preferably polyether polyol. Examples of polyether polyols include poly(ethylene glycol), poly(propylene glycol), poly(butylene glycol), polyoxyethylene glyceryl ether, and polyoxypropylene glyceryl ether.

The average number of functional groups of the polyol used to form the urethane-based polymer is about 2 or more, preferably about 2.5 or more (for example, about 2.8 or more) from the viewpoint of improving cohesion. The above-mentioned average number of functional groups is usually about 5 or less, and it is preferably about 4 or less (for example, about 3.5 or less) from the viewpoint of adhesive force and the like.

The molecular weight of the above-mentioned polyol is appropriately set according to electrical conductivity, adhesive properties, etc., so it is not limited to a specific range, but it is usually about 300 or more, preferably about 500 or more, preferably about 800 or more, may be about 1000 or more, may be about 3000 or more, and may be about 5000 or more. The upper limit of the molecular weight of the above-mentioned polyol is, for example, less than 3.0×10 ⁴ , preferably less than about 2.0×10 ⁴ , or less than about 1.5×10 ⁴ , or less than about 1.2×10 ⁴ (for example, less than 1.0×10 ⁴ ). The aforementioned polyol may also be a polymer having a number average molecular weight of about 10×10 ⁴ or less (for example, about 5×10 ⁴ or less).

In some preferred aspects, the polyol used to form the above-mentioned urethane-based polymer may be one or more of a polyol (main polyol) as a main component and a subcomponent polyol (subpolyol) having a molecular weight lower than that of the main component. The effect of the technology disclosed in this application can be better exerted or adjusted by using the main polyol and the auxiliary polyol in combination. The types of the main polyol and the subpolyol are not particularly limited, and may be any of polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol, for example. Among them, polyester polyol and polyether polyol are preferred, and polyether polyol is more preferred. Specific examples of polyether polyols include the polyether polyols exemplified above.

The molecular weight of the main polyol used is not limited to a specific range because it is appropriately set according to electrical conductivity, adhesive properties, etc., but it is usually about 3000 or more, preferably about 5000 or more (for example, about 8000 or more). The upper limit of the molecular weight of the main polyol is, for example, less than 3.0×10 ⁴ , preferably less than about 2.0×10 ⁴ , or less than about 1.5×10 ⁴ (for example, less than 1.2×10 ⁴ ). As the subpolyol, one or two or more polyols having a molecular weight smaller than that of the main polyol can be used. The molecular weights of one or more subpolyols are about 300 or more, preferably about 500 or more, preferably about 800 or more, or about 1,000 or more, for example, about 1,500 or more, and for example, less than about 1.0×10 ⁴ , preferably about 7,000 or less, more preferably about 5,000 or less, or about 2,500 or less, such as about 1,200 or less.

The average number of functional groups in the main polyol is about 2 or more, and it is preferably about 2.5 or more (for example, about 2.8 or more) from the viewpoint of improving the cohesive force. The above-mentioned average number of functional groups is usually about 5 or less, and it is preferably about 4 or less (for example, about 3.5 or less) from the viewpoint of adhesive force and the like. The average number of functional groups in the subpolyol is about 2 or more, and it is preferably about 2.5 or more (for example, about 2.8 or more) from the viewpoint of improving the cohesive force. The above-mentioned average number of functional groups is usually about 5 or less, and it is preferably about 4 or less (for example, about 3.5 or less) from the viewpoint of adhesive force and the like.

Regarding the polyol used to form the above-mentioned urethane-based polymer, in the aspect where the main polyol and the subpolyol are used together, the weight ratio of the main polyol to the subpolyol (main polyol/subpolyol) is not particularly limited. In addition, the above-mentioned weight ratio (main polyol/subpolyol) can be set to, for example, about 99/1 or less, preferably about 95/5 or less (for example, about 90/10 or less).

About the polyfunctional isocyanate used for forming the said urethane-type polymer, 1 type or 2 or more types of suitable compounds can be selected from the compound which has several isocyanate groups. Examples of polyfunctional isocyanates include aromatic isocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; and aliphatic isocyanates such as butylene diisocyanate and hexamethylene diisocyanate. More specifically, isocyanate adducts such as trimethylolpropane/toluene diisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name "CORONATE L"), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name "CORONATE HL"), isocyanurate body of hexamethylene diisocyanate (manufactured by Tosoh Corporation, brand name "CORONATE HX"), and the like are preferably used. These polyfunctional isocyanates may be used alone or in combination of two or more.

The polyol and the polyfunctional isocyanate are prepared so that the equivalent ratio (NCO group/OH group) of the OH group of the polyol to the NCO group of the polyfunctional isocyanate is in an appropriate range. The above-mentioned equivalent ratio (NCO group/OH group) is usually about 5.0 or less, preferably about 3.0 or less, may be about 2.5 or less, and may be about 2.0 or less. In addition, the above-mentioned equivalent ratio (NCO group/OH group) is usually about 0.1 or more (for example, about 0.2 or more), preferably about 0.3 or more, and may be about 0.5 or more.

The content of the polyfunctional isocyanate used to form the above-mentioned urethane-based polymer can be set according to the equivalent ratio (NCO group/OH group) of the above-mentioned polyol, the molecular weight of the polyol, the molecular weight of the polyfunctional isocyanate, etc., so it is not limited to a specific range. In the adhesive composition for forming the adhesive layer, the content of the above-mentioned polyfunctional isocyanate may be, for example, about 1 part by weight or more, preferably about 5 parts by weight or more, preferably about 10 parts by weight or more, or about 15 parts by weight or more relative to 100 parts by weight of the above-mentioned polyol. Also, the upper limit of the content of the polyfunctional isocyanate relative to 100 parts by weight of the above-mentioned polyol may be, for example, about 50 parts by weight or less, preferably about 30 parts by weight or less, preferably about 25 parts by weight or less, for example, about 20 parts by weight or less.

The urethane-based polymer disclosed in this application can be obtained by reacting the adhesive composition comprising the above-mentioned polyol and polyfunctional isocyanate, using a catalyst if necessary, under specific temperature conditions. The reaction temperature is usually about 85°C or higher, for example, preferably about 100°C or higher, preferably about 115°C or higher. The upper limit of the reaction temperature is, for example, preferably set at 170°C or lower, and may be about 150°C or lower.

The content ratio of the polymer of the oxyalkylene group-containing structural unit in the adhesive layer disclosed in this application is set according to the electrical conductivity to the adherend, etc., and therefore is not limited to a specific range. The content ratio of the oxyalkylene structural unit polymer in the adhesive layer can be, for example, about 30% by weight or more. From the viewpoint of improving electrical conductivity, bonding reliability, and separation and removal of the adhered body, it is preferably about 50% by weight or more (generally more than 50% by weight), preferably about 60% by weight or more, more preferably about 70% by weight or more, still more preferably about 80% by weight or more, and may be more than about 90% by weight. In consideration of adhesion reliability, separation and removal of the adherend, conductivity, etc., the upper limit of the content ratio of the oxyalkylene structural unit polymer in the adhesive layer is preferably about 95% by weight or less, for example, about 90% by weight or less.

(ionic compounds) The adhesive layer (or adhesive composition) disclosed in this application preferably contains ionic compounds as conductive components. By including the ionic compound, the adhesive layer can preferably exhibit good electrical conductivity. The use of an ionic compound is preferable from the viewpoint of maintaining the transparency of the adhesive layer. In the aspect of using the adhesive layer containing the oxyalkylene structural unit, the oxyalkylene structural unit in the adhesive layer can exhibit good conductivity by serving as a moving medium for the ionic compound or electrically supporting the ionic compound.

As an ionic compound, an alkali metal salt, an ionic liquid, etc. can be illustrated. These may be used individually by 1 type, and may use it in combination of 2 or more types. Furthermore, the so-called "ionic liquid" (sometimes called room temperature molten salt) in this case refers to a molten salt (ionic compound) that is liquid below 40°C. Since the ionic liquid is liquid below 40° C., it is easier to add, disperse or dissolve in the adhesive than solid salt in this temperature range. Furthermore, since the ionic liquid has no vapor pressure (non-volatility), it will not disappear with time and can continue to exhibit electrical conductivity.

(Alkali Metal Salt) In some preferred aspects, an alkali metal salt is used as the ionic compound. Typical examples of alkali metal salts include lithium salts, sodium salts, and potassium salts. For example, Li ⁺ , Na ⁺ or K ⁺ as a cationic component and Cl ^- , Br ^- , I ^- , BF ₄ - , PF ₆ ^- , SCN ^- , ClO ₄ ^- , CF ₃ SO ₃ ^- , (FSO ₂ ) ₂ N - , (CF 3 SO 2 ) 2 N ^- , (C _{2 F 5 SO 2 ) 2 N - , (C 2 F 5 SO 2 ) 2 N -} ^{or (} CF ₃ SO ₂ ) ₃ C ^- metal salt composed of. From the standpoint of high dissociation, lithium salts are preferably used. Preferable specific examples include lithium salts such as LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, and Li(CF ₃ SO ₂ ) ₃ C. Among them, lithium salts of fluorine-containing anions such as bis(perfluoroalkylsulfonyl)imide anion and perfluoroalkylconium anion are particularly preferred as the anion component (such as Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, LiCF ₃ SO ₃ ). These alkali metal salts may be used alone or in combination of two or more.

(ionic liquid) Regarding the above-mentioned ionic liquid, any one or more of nitrogen-containing onium salts, sulfur-containing onium salts, and phosphorus-containing onium salts can be preferably used. In a preferred aspect, the adhesive layer includes an ionic liquid having at least one organic cationic component represented by any one of the following general formulas (A) to (E).

[chemical formula 1]

Wherein in the above formula (A), R _a represents a hydrocarbon group with 4 to 20 carbon atoms or a functional group containing heteroatoms. R _b and R _c may be the same or different, and represent a hydrogen atom or a hydrocarbon group with 1 to 16 carbon atoms or a functional group including a heteroatom, respectively. However, when the nitrogen atom contains a double bond, R _c does not exist. In the above formula (B), R _d represents a hydrocarbon group having 2 to 20 carbon atoms or a functional group including a heteroatom. R _e , R _f and R _g may be the same or different, and represent a hydrogen atom or a hydrocarbon group with 1 to 16 carbon atoms or a functional group containing heteroatoms, respectively. In the above formula (C), _Rh represents a hydrocarbon group having 2 to 20 carbon atoms or a functional group including a heteroatom. R _i , R _j and R _k may be the same or different, and each represent a hydrogen atom or a hydrocarbon group with 1 to 16 carbon atoms or a functional group containing a heteroatom. In the above formula (D), Z represents a nitrogen atom, a sulfur atom or a phosphorus atom. R _l , R _m , R _n and R _o may be the same or different, and represent a hydrocarbon group with 1 to 20 carbon atoms or a functional group containing heteroatoms, respectively. However, when Z is a sulfur atom, R _o does not exist. In the above formula (E), R _p represents a hydrocarbon group having 1 to 18 carbon atoms or a functional group including a heteroatom.

The cation represented by the formula (A) may, for example, be a pyridinium cation, a pyrrolidinium cation, a piperidinium cation, a cation having a pyrroline skeleton, or a cation having a pyrrole skeleton.

Specific examples of pyridinium cations include: 1-methylpyridinium, 1-ethylpyridinium, 1-propylpyridinium, 1-butylpyridinium, 1-pentylpyridinium, 1-hexylpyridinium, 1-heptylpyridinium, 1-octylpyridinium, 1-nonylpyridinium, 1-decylpyridinium, 1-allylpyridinium, 1-propyl-2-methylpyridinium, 1-butyl-2-methylpyridinium Pyridinium, 1-pentyl-2-methylpyridinium, 1-hexyl-2-methylpyridinium, 1-heptyl-2-methylpyridinium, 1-octyl-2-methylpyridinium, 1-nonyl-2-methylpyridinium, 1-decyl-2-methylpyridinium, 1-propyl-3-methylpyridinium, 1-butyl-3-methylpyridinium, 1-butyl-4-methylpyridinium, 1-heptyl-3-methylpyridinium, 1-hexyl-3-methylpyridinium, 1-heptyl-3-methylpyridinium, 1-octyl-3-methylpyridinium, 1-octyl-4-methylpyridinium, 1-nonyl-3-methylpyridinium, 1-decyl-3-methylpyridinium, 1-propyl-4-methylpyridinium, 1-heptyl-4-methylpyridinium, 1-hexyl-4-methylpyridinium, 1-heptyl-4-methylpyridinium, 1-nonyl Base-4-methylpyridinium, 1-decyl-4-methylpyridinium, 1-butyl-3,4-dimethylpyridinium, etc.

Specific examples of pyrrolidinium cations include: 1,1-dimethylpyrrolidinium, 1-ethyl-1-methylpyrrolidinium, 1-methyl-1-propylpyrrolidinium, 1-methyl-1-butylpyrrolidinium, 1-methyl-1-pentylpyrrolidinium, 1-methyl-1-hexylpyrrolidinium, 1-methyl-1-heptylpyrrolidinium, 1-methyl-1-octylpyrrolidinium, 1-methyl-1- Nonylpyrrolidinium, 1-methyl-1-decylpyrrolidinium, 1-methyl-1-methoxyethoxyethylpyrrolidinium, 1-ethyl-1-propylpyrrolidinium, 1-ethyl-1-butylpyrrolidinium, 1-ethyl-1-pentylpyrrolidinium, 1-ethyl-1-hexylpyrrolidinium, 1-ethyl-1-heptylpyrrolidinium, 1,1-dipropylpyrrolidinium, 1-propylpyrrolidinium -1-butylpyrrolidinium, 1,1-dibutylpyrrolidinium, pyrrolidinium-2-one, etc.

Specific examples of piperidinium cations include: 1-propylpiperidinium, 1-pentylpiperidinium, 1,1-dimethylpiperidinium, 1-methyl-1-ethylpiperidinium, 1-methyl-1-propylpiperidinium, 1-methyl-1-butylpiperidinium, 1-methyl-1-pentylpiperidinium, 1-methyl-1-hexylpiperidinium, 1-methyl-1-heptylpiperidinium, 1-methyl-1-octylpiperidinium , 1-methyl-1-decylpiperidinium, 1-methyl-1-methoxyethoxyethylpiperidinium, 1-ethyl-1-propylpiperidinium, 1-ethyl-1-butylpiperidinium, 1-ethyl-1-pentylpiperidinium, 1-ethyl-1-hexylpiperidinium, 1-ethyl-1-heptylpiperidinium, 1,1-dipropylpiperidinium, 1-propyl-1-butylpiperidinium, 1-propyl- 1-pentylpiperidinium, 1-propyl-1-hexylpiperidinium, 1-propyl-1-heptylpiperidinium, 1,1-dibutylpiperidinium, 1-butyl-1-pentylpiperidinium, 1-butyl-1-hexylpiperidinium, 1-butyl-1-heptylpiperidinium, etc.

Specific examples of the cation having a pyrroline skeleton include 2-methyl-1-pyrroline and the like. Specific examples of the cation having a pyrrole skeleton include 1-ethyl-2-phenylindole, 1,2-dimethylindole, 1-ethylcarbazole, and the like.

The cation represented by the formula (B) may, for example, be an imidazolium cation, a tetrahydropyrimidinium cation or a dihydropyrimidinium cation.

Specific examples of imidazolium cations include: 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1-methyl-3-ethylimidazolium, 1-methyl-3-hexylimidazolium, 1-ethyl-3-methylimidazolium, 1-propyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-pentyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-heptyl -3-methylimidazolium, 1-octyl-3-methylimidazolium, 1-nonyl-3-methylimidazolium, 1-decyl-3-methylimidazolium, 1-dodecyl-3-methylimidazolium, 1-tetradecyl-3-methylimidazolium, 1-hexadecyl-3-methylimidazolium, 1-octadecyl-3-methylimidazolium, 1,2-dimethyl-3-propylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1 -Butyl-2,3-dimethylimidazolium, 1-hexyl-2,3-dimethylimidazolium, 1-(2-methoxyethyl)-3-methylimidazolium, and the like.

Specific examples of tetrahydropyrimidinium cations include 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium, and the like.

Specific examples of dihydropyrimidinium cations include: 1,3-dimethyl-1,4-dihydropyrimidinium, 1,3-dimethyl-1,6-dihydropyrimidinium, 1,2,3-trimethyl-1,4-dihydropyrimidinium, 1,2,3-trimethyl-1,6-dihydropyrimidinium, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium, 1,2,3,4-tetramethyl-1,6 - Dihydropyrimidinium and the like.

As for the cation represented by the formula (C), a pyrazolium cation, a dihydropyrazolium cation, and the like can be illustrated.

Specific examples of the pyrazolium cation include 1-methylpyrazolium, 3-methylpyrazolium, 1-ethyl-2,3,5-trimethylpyrazolium, 1-propyl-2,3,5-trimethylpyrazolium, 1-butyl-2,3,5-trimethylpyrazolium, 1-(2-methoxyethyl)pyrazolium, and the like. Specific examples of the dihydropyrazolium cation include 1-ethyl-2-methyldihydropyrazolium and the like.

Regarding the cation represented by the formula (D), it can be exemplified that each of R _l , R _m , R _n and R _o which are the same or different is a cation of an alkyl group having 1 to 20 carbon atoms. As for the cation, tetraalkylammonium cations, trialkylconium cations, and tetraalkylphosphonium cations can be exemplified. Other examples of the cation represented by the formula (D) include those in which part of the above-mentioned alkyl group is substituted with an alkenyl group, an alkoxy group, or an epoxy group. Also, one or more of R _l , R _m , R _n and R _o may contain an aromatic ring or an aliphatic ring.

The cation represented by the formula (D) may be a cation with a symmetrical structure or an asymmetrical cation. Regarding ammonium cations with symmetrical structures, it can be illustrated that R ₁ , R _m , R _n and R _o are tetraalkylammonium cations in which the same alkyl group (for example, any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, hexadecyl, and octadecyl) is present.

Regarding the representative example of asymmetric ammonium cations, R_l , R_m , R_no and R_o Three of them are the same and the remaining one is different tetraalkylammonium cations. Specific examples are: trimethylethylammonium, trimethylpropylammonium, trimethylbutylammonium, trimethylpentylammonium, trimethylhexylammonium, trimethylheptylammonium, trimethyloctylammonium, trimethylnonylammonium, trimethyldecylammonium, triethylmethylammonium, triethylpropylammonium, triethylbutylammonium, triethylpentylammonium, triethylhexylammonium, triethylheptylammonium, triethyloctylammonium, Triethyl nonyl ammonium, triethyl decyl ammonium, tripropyl methyl ammonium, tripropyl ethyl ammonium, tripropyl butyl ammonium, tripropyl pentyl ammonium, tripropyl hexyl ammonium, tripropyl heptyl ammonium, tripropyl octyl ammonium, tripropyl nonyl ammonium, tripropyl decyl ammonium, tributyl methyl ammonium, tributyl ethyl ammonium, tributyl propyl ammonium, tributyl pentyl ammonium, tributyl hexyl ammonium, tributyl heptyl ammonium, tripentyl methyl ammonium, Tripentylethylammonium, tripentylpropylammonium, tripentylbutylammonium, tripentylhexylammonium, tripentylheptylammonium, trihexylmethylammonium, trihexylethylammonium, trihexylpropylammonium, trihexylbutylammonium, trihexylpentylammonium, trihexylheptylammonium, triheptylmethylammonium, triheptylethylammonium, triheptylpropylammonium, Asymmetric tetraalkylammonium cations such as trioctyl ethyl ammonium, trioctyl propyl ammonium, trioctyl butyl ammonium, trioctyl pentyl ammonium, trioctyl hexyl ammonium, trioctyl heptyl ammonium, trioctyl dodecyl ammonium, trioctyl hexadecyl ammonium, trioctyl octadecyl ammonium, trinonyl methyl ammonium, tridecyl methyl ammonium.

Other examples of asymmetric ammonium cations include: dimethyl diethyl ammonium, dimethyl dipropyl ammonium, dimethyl dibutyl ammonium, dimethyl dipentyl ammonium, dimethyl dihexyl ammonium, dimethyl diheptyl ammonium, dimethyl dioctyl ammonium, dimethyl dinonyl ammonium, dimethyl didecyl ammonium, dipropyl diethyl ammonium, dipropyl dibutyl ammonium, dipropyl dipentyl ammonium, dipropyl dihexyl ammonium, dimethyl ethyl propyl ammonium, dimethyl ethyl butyl ammonium ammonium, dimethylethylpentylammonium, dimethylethylhexylammonium, dimethylethylheptylammonium, dimethylethylnonylammonium, dimethylpropylbutylammonium, dimethylpropylpentylammonium, dimethylpropylhexylammonium, dimethylpropylheptylammonium, dimethylbutylhexylammonium, dimethylbutylheptylammonium, dimethylpentylhexylammonium, dimethylhexylheptylammonium, diethylmethylpropylammonium, diethylmethylpentylammonium, diethylmethylheptylammonium, Ethylpropylpentylammonium, dipropylmethylethylammonium, dipropylmethylpentylammonium, dipropylbutylhexylammonium, dibutylmethylpentylammonium, dibutylmethylhexylammonium, methylethylpropylbutylammonium, methylethylpropylpentylammonium, methylethylpropylhexylammonium and other tetraalkylammonium cations; trimethylcyclohexylammonium and other ammonium cations containing cycloalkyl ammonium; Alkenyl-containing ammonium cations such as diallylmethyloctyl ammonium; alkoxy-containing ammonium cations such as triethyl(methoxyethoxyethyl)ammonium, dimethylethyl(methoxyethoxyethyl)ammonium, dimethylethyl(ethoxyethoxyethyl)ammonium, diethylmethyl(2-methoxyethyl)ammonium, diethylmethyl(methoxyethoxyethyl)ammonium); epoxypropyltrimethylammonium-containing ammonium cations and the like.

As for the permeium cation with a symmetrical structure, for example, a trialkyl percite cation in which R _l , R _m and R _n are the same alkyl group (such as any one of methyl, ethyl, propyl, butyl, and hexyl) can be exemplified. Examples of the asymmetrical cobalt cation include asymmetric trialkyl cobalt cations such as dimethyldecyl cobalt, diethylmethyl cobalt, and dibutylethyl cobalt.

Regarding phosphonium cations with symmetrical structures, examples include tetraalkylphosphonium cations in which R ₁ , R _m , R _n , and R _o are the same alkyl group (for example, any one of methyl, ethyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl). Regarding the asymmetric phosphonium cation, three of R _l , R _m , R _n and R _o are the same, and the remaining one is different tetraalkylphosphonium cations. Specific examples include: trimethylpentylphosphonium, trimethylhexylphosphonium, trimethylheptylphosphonium, trimethyloctylphosphonium, trimethylnonylphosphonium, trimethyldecylphosphonium, triethylmethylphosphonium, tributylethylphosphonium, tributyl-(2-methoxyethyl)phosphonium, tripentylmethylphosphonium, trihexylmethylphosphonium, triheptylphosphonium ylmethylphosphonium, trioctylmethylphosphonium, trinonylmethylphosphonium, tridecylmethylphosphonium, etc. Other examples of asymmetric phosphonium cations include asymmetric tetraalkylphosphonium cations such as trihexyltetradecylphosphonium, dimethyldipentylphosphonium, dimethyldihexylphosphonium, dimethyldiheptylphosphonium, dimethyldioctylphosphonium, dimethyldinonylphosphonium, and dimethyldidecylphosphonium;

Preferable examples of the cations represented by the formula (D) include the above-mentioned asymmetric tetraalkylammonium cations, asymmetric trialkylconium cations, and asymmetric tetraalkylphosphonium cations.

The cation represented by the formula (E) can be exemplified as a percite cation in which R _p is any one of an alkyl group having 1 to 18 carbon atoms. Specific examples of R _p include methyl, ethyl, propyl, butyl, hexyl, octyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl, octadecyl and the like.

The anion component of the above-mentioned ionic liquid is not particularly limited as long as it can become an ionic liquid with a salt of any one of the cations disclosed in this application.關於具體例，可列舉：Cl ^- 、Br ^- 、I ^- 、AlCl ₄ ^- 、Al ₂ Cl ₇ ^- 、BF ₄ ^- 、PF ₆ ^- 、ClO ₄ ^- 、NO ₃ ^- 、CH ₃ COO ^- 、CF ₃ COO ^- 、CH ₃ SO ₃ ^- 、CF ₃ SO ₃ ^- 、(FSO ₂ ) ₂ N ^- 、(CF ₃ SO ₂ ) ₂ N ^- 、(CF ₃ SO ₂ ) ₃ C ^- 、AsF ₆ ^- 、SbF ₆ ^- 、NbF ₆ ^- 、TaF ₆ ^- 、F(HF) _n ^- 、(CN) ₂ N ^- 、C ₄ F ₉ SO ₃ ^- 、(C ₂ F ₅ SO ₂ ) ₂ N ^- 、C ₃ F ₇ COO ^- 、(CF ₃ SO ₂ )(CF ₃ CO)N ^- 、C ₉ H ₁₉ COO ^- 、(CH ₃ ) ₂ PO ₄ ^- 、(C ₂ H ₅ ) ₂ PO ₄ ^- 、C ₂ H ₅ OSO ₃ ^- 、C ₆ H ₁₃ OSO ₃ ^- 、C ₈ H ₁₇ OSO ₃ ^- 、CH ₃ (OC ₂ H ₄ ) ₂ OSO ₃ ^- 、C ₆ H ₄ (CH ₃ )SO ₃ ^- 、(C ₂ F ₅ ) ₃ PF ₃ ^- 、CH ₃ CH(OH)COO ^- 、及下述式(F)表示之陰離子。

[chemical formula 2]

Among them, the hydrophobic anionic component tends to be difficult to seep out on the surface of the adhesive, so it is suitable for use from the viewpoint of low pollution. Also, an anionic component containing a fluorine atom (for example, an anionic component containing a perfluoroalkyl group) can be preferably used because an ionic compound with a low melting point can be obtained. Preferable examples of the anion component include bis(perfluoroalkylsulfonyl)imide anions (such as (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ ), perfluoroalkylconium anions (such as CF ₃ SO ₃ ⁻ ), and other fluorine-containing anions. The number of carbon atoms in the above-mentioned perfluoroalkyl group is usually preferably 1 to 3, preferably 1 or 2 among them.

The ionic liquid used in the technique disclosed in this application may be an appropriate combination of the above-mentioned cationic components and anionic components. As an example, when the cation component is a pyridinium cation, specific combinations with the aforementioned anion components include: 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylpyridinium Pyridinium bis(pentafluoroethanesulfonyl)imide, 1-hexylpyridinium tetrafluoroborate, 1-allylpyridinium bis(trifluoromethanesulfonyl)imide, and the like. Regarding each of the above-mentioned other cations, the ionic liquid related to the combination of any one of the anion components disclosed in this application can also be used in the same way.

Such an ionic liquid can use a commercially available one, or can be easily synthesized by a known method. The synthesis method of the ionic liquid is not particularly limited as long as the desired ionic liquid can be obtained. In general, the halide method, hydroxide method, acid ester method, complex formation method, and neutralization method described in the well-known literature "Ionic Liquids-The Frontline and Future of Development-" (published by CMC) can be used.

(Other ionic compounds) Also, as ionic compounds, inorganic salts such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, and ammonium sulfate can be used in addition to the above-mentioned alkali metal salts and ionic liquids (for example, organic cation-anion salts). Also, the ionic compounds disclosed in this case include those generally called ionic surfactants. Examples of ionic surfactants include cationic surfactants having cationic functional groups such as quaternary ammonium salts, phosphonium salts, permeic acid salts, pyridinium salts, and amine groups; anionic surfactants having anionic functional groups such as carboxylic acids, sulfonates, sulfates, phosphates, and phosphites; These may be used individually by 1 type, and may use it in combination of 2 or more types.

The amount of the ionic compound contained in the adhesive layer is not particularly limited, and may be at least about 1% by weight in the adhesive layer (in the solid content of the adhesive composition). From the viewpoint of improving electrical conductivity, it is preferably at least about 3% by weight, preferably at least about 6% by weight, more preferably at least about 9% by weight, and even more preferably at least about 12% by weight. The amount of the ionic compound in the adhesive layer is usually about 40% by weight or less. From the viewpoint of the influence on the adhesive properties and the prevention of contamination by the adhesive, it is preferably about 30% by weight or less, preferably about 25% by weight or less (for example, about 20% by weight or less).

Furthermore, in the adhesive layer disclosed in this case, the conductive agent may contain organic conductive substances such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine-based polymers, or inorganic materials such as tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, indium copper iodide, ITO (tin oxide/tin oxide), ATO (antimony oxide/tin oxide) and other metal particles or metal oxide particles. conductive substance. As the conductive agent, inorganic composite conductive materials such as glass and other inorganic particles coated with metals such as silver, or organic-inorganic composite conductive materials such as inorganic particles coated with organic materials such as conductive polymers can also be used. From the point of view of both adhesive force and bonded body separation and removal, and transparency, the content of conductive substances (generally inorganic conductive substances) other than such ionic compounds in the adhesive layer is preferably limited to less than 20% by volume, preferably less than 10% by volume, more preferably less than 3% by volume, and even more preferably less than 1% by volume. The technology disclosed in this application can be preferably implemented in a state where the adhesive layer does not substantially contain conductive substances other than ionic compounds.

In the technique disclosed in this case, the form of the adhesive composition used to form the adhesive layer is not particularly limited. For example, an adhesive composition containing an adhesive component in an organic solvent (solvent-type adhesive composition), an adhesive composition in which the adhesive component is dispersed in an aqueous solvent (water-dispersed adhesive composition, generally an aqueous emulsion-type adhesive composition), an adhesive composition in which the adhesive component is dissolved in water (aqueous solution-type adhesive composition), a solvent-free adhesive composition (for example, an adhesive of a type hardened by irradiation with active energy rays such as ultraviolet rays or electron beams) composition, hot melt adhesive composition), etc. In some preferred aspects, the adhesive sheet has an adhesive layer formed of a solvent-based adhesive composition. The organic solvent contained in the above-mentioned solvent-based adhesive composition can be, for example, a single solvent composed of any one of toluene, xylene, ethyl acetate, hexane, cyclohexane, methylcyclohexane, heptane, and isopropanol, or a mixed solvent with any one of them as the main component.

In the technology disclosed in this case, the adhesive composition (preferably a solvent-based adhesive composition) used to form the adhesive layer can preferably be formed in such a way that the polymer contained in the composition (generally, a polymer containing oxygen alkylene structural units) is properly cross-linked. Regarding the specific cross-linking method, the following method can be preferably adopted: by copolymerizing monomers having appropriate functional groups (hydroxyl, carboxyl, etc.) to introduce cross-linking base points into the above-mentioned polymer, and then adding a compound (cross-linking agent) that can react with its functional group to form a cross-linking structure in the above-mentioned polymer to make it react.

The type of crosslinking agent used is not particularly limited, for example, isocyanate crosslinking agent, epoxy crosslinking agent, oxazoline crosslinking agent, aziridine crosslinking agent, melamine crosslinking agent, peroxide crosslinking agent, urea crosslinking agent, metal alkoxide crosslinking agent, metal chelate crosslinking agent, metal salt crosslinking agent, carbodiimide crosslinking agent, amine crosslinking agent, etc. These crosslinking agents can be used individually by 1 type or in combination of 2 or more types. Among them, an isocyanate-based crosslinking agent is preferred.

The amount of crosslinking agent used can be appropriately selected according to the type, structure, molecular weight, etc. of the polymer, adhesive properties such as adhesive force or peelability, and the like. For example, by setting the usage amount of the crosslinking agent to be more than a specific amount, the cohesive force of the adhesive can be improved, and adhesive residue can be prevented from being left on the adherend. From this point of view, the amount of the crosslinking agent relative to 100 parts by weight of the polymer (generally a polymer containing an oxyalkylene group structural unit) is preferably about 0.01 parts by weight or more, preferably about 0.1 parts by weight or more (for example, about 0.2 parts by weight or more). Also, the amount of the above-mentioned crosslinking agent used is preferably not more than about 10 parts by weight (for example, not more than about 5 parts by weight). In the aspect of using an isocyanate-based cross-linking agent as the cross-linking agent, the amount of the isocyanate-based cross-linking agent is preferably about 0.5 parts by weight or more, preferably about 1 part by weight or more, more preferably about 1.5 parts by weight or more (for example, about 2 parts by weight or more), and can be set to about 3 parts by weight or less relative to 100 parts by weight of the polymer (generally, a polymer containing an oxygen alkylene structural unit).

For the purpose of promoting various reactions related to the formation of the adhesive layer, the above-mentioned adhesive composition may further include a catalyst. The aforementioned catalyst may be what is called a crosslinking catalyst or a hardening catalyst. The type of catalyst can be appropriately selected according to the type of compound (crosslinking agent, etc.) to be used. Regarding the catalyst, for example, iron-containing compounds such as iron acetylacetonate and iron 2-ethylhexanoate, organometallic compounds such as tin (Sn) compounds such as iron acetylacetonate and iron 2-ethylhexanoate, dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin diacetylate, dibutyltin diacetylacetone, tetra-n-butyltin, and trimethyltin hydroxide, tetraisopropyl titanate, titanium-containing compounds such as tetra-n-butyl titanate, and the like; Amines such as tetramethylhexamethylenediamine and triethylamine, nitrogen (N) compounds such as imidazoles; basic compounds such as lithium hydroxide, potassium hydroxide, sodium methoxide, etc.; acidic compounds such as p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, monoalkyl phosphoric acid, dialkyl phosphoric acid, and phosphoric acid ester of β-hydroxyethyl acrylate, etc. These can be used individually by 1 type or in combination of 2 or more types. The amount of the catalyst included in the adhesive composition can be, for example, about 0.001 to 10 parts by weight (preferably about 0.005 to 5 parts by weight) relative to 100 parts by weight of the polymer.

The technique disclosed in this case can also be implemented by using an adhesive layer comprising a polymer different from the polymer containing the oxyalkylene structural unit (ie, a polymer not containing the oxyalkylene structural unit). In the aspect where the adhesive layer includes a polymer containing an oxyalkylene structural unit, in addition to the polymer containing an oxyalkylene structural unit, a polymer not containing the above-mentioned oxyalkylene structural unit may also be included. As the polymer not containing the above-mentioned oxyalkylene structural unit, various polymers exemplified above, that is, those having no oxyalkylene structural unit can be used. The content of the polymer containing no oxyalkylene structural unit in the adhesive layer is set according to the target adhesive property and electrical conductivity, and is not limited to a specific range. For example, the adhesive layer (in the solid content of the adhesive composition) can be set to about 70% by weight or less, preferably about 50% by weight or less. From the viewpoint of fully exerting the role of other adhesive layer constituents such as polymers containing oxyalkylene group structural units, it is preferably about 30% by weight or less, preferably about 10% by weight or less, more preferably about 3% by weight or less (for example, 0 to 1% by weight).

In the above-mentioned adhesive composition, various previously known additives may be further formulated as needed. Examples of such additives include surface lubricants, leveling agents, antioxidants, preservatives, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, and the like. Moreover, tackiness imparting resin and peeling regulator can also be prepared. Furthermore, the adhesive layer disclosed in this application may contain or not contain alkylene oxide compounds such as polyethylene glycol or polypropylene glycol. When using emulsion polymerization to synthesize adhesive polymers, it is advisable to use emulsifiers or chain transfer agents (also known as molecular weight regulators or polymerization degree regulators).

(Formation method of adhesive layer) The adhesive layer in the technique disclosed in this application can be formed, for example, by a method (direct method) in which the above-mentioned adhesive composition is directly applied to the substrate film and then dried or cured. Alternatively, it can also be formed by applying the above-mentioned adhesive composition to the surface (release surface) of the release liner, drying or hardening it to form an adhesive layer on the surface, attaching the thus-formed adhesive layer to a base film, and transferring the adhesive layer (transfer method). From the viewpoint of the anchoring property of the adhesive layer, it is generally preferable to adopt the direct method. When applying (generally coating) the adhesive composition, roll coating, gravure coating, reverse coating, roll brushing, spraying, air knife coating, coating with a slit coater, and various methods known in the field of adhesive sheets can be suitably used. Drying of the adhesive composition can be carried out under heating (for example, by heating to about 60° C. to 150° C.) if necessary. As a method for curing the adhesive composition, ultraviolet rays, laser rays, alpha rays, beta rays, gamma rays, X rays, electron beams, etc. can be suitably used.

(thickness of adhesive layer) Although not particularly limited, the thickness of the adhesive layer can be, for example, about 1 μm or more, and is preferably about 3 μm or more, preferably about 5 μm or more (for example, about 7 μm or more) from the viewpoint of adhesion reliability to the adherend. In addition, the above-mentioned thickness can be set to, for example, about 100 μm or less, and is preferably set to about 50 μm or less, preferably about 30 μm or less (for example, about 20 μm or less) from the standpoint of separation and removability of the adherend. The adhesive layer disclosed in this case exhibits good electrical conductivity without using conductive agents such as metal particles, so it is possible to form an adhesive layer showing a surface resistance value below a specified value in a relatively thin thickness.

<Adhesive composition> As described above, the adhesive layer of the adhesive sheet disclosed in this application is formed of an adhesive composition. Therefore, the technology disclosed in this case includes the adhesive composition. According to the above-mentioned adhesive composition, the following adhesive can be preferably realized: the electrical conductivity above the specified level and the adhesive force within the specified range, for example, the surface resistance value is below 1.0×10 ⁸ Ω/□, and the adhesive force to the SUS board is within the range of 0.01~4.0N/20mm. The adhesive composition disclosed in this application may contain the oxyalkylene structural unit as mentioned above. Some preferred adhesive compositions include polymers having oxyalkylene structural units and/or oligomers or monomers used to form the polymers, and may further include ionic compounds as optional components, or various additional components. The details about the composition (specific examples and contents of the components contained) are as above, so the description will not be repeated.

＜Substrate layer＞ In the single-sided adhesive type or double-sided adhesive type adhesive sheet with a base material, various base films can be used for the base material layer for supporting (backing) the adhesive layer. As the above-mentioned base film, resin films, paper, cloth, rubber sheets, foam sheets, metal foils, composites thereof, and the like can be used. Among them, a resin film is preferably used. The so-called resin film in this case is generally a non-porous resin sheet. For example, the concept is different from non-woven fabric (that is, it does not contain non-woven fabric). Usually, various resin materials are formed into a film shape.

Examples of resin films include polyolefin resin films such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers; polyester resin films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); vinyl chloride resin films; vinyl acetate resin films; polyimide resin films; polyamide resin films; fluororesin films; cellophane, and the like. The above-mentioned resin film may have a single-layer structure, or may have a structure in which a plurality of laminated layers with different compositions are formed. Generally, it is preferable to use a resin film with a single-layer structure.

Examples of paper include Japanese paper, kraft paper, cellophane, high-quality paper, synthetic paper, and topcoat paper. Examples of cloth include woven or non-woven fabrics of various fibrous materials alone or by blending. Examples of the fibrous material include cotton, staple fiber, Manila hemp, pulp, rayon, acetate fiber, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, polyolefin fiber, and the like. As an example of a rubber sheet, a natural rubber sheet, a butyl rubber sheet, etc. are mentioned. Examples of the foam sheet include foamed polyurethane sheets, foamed polychloroprene rubber sheets, and the like. As an example of metal foil, aluminum foil, copper foil, etc. are mentioned.

The modulus of elasticity of the base film (generally a resin film) constituting the base layer is not particularly limited, but it is preferably about 50 MPa or more from the viewpoint of having a certain rigidity to stably support the adherend. In addition, from the viewpoint of adhesiveness, handleability, etc., the elastic modulus is preferably about 50,000 MPa or less. The modulus of elasticity of the base film can be set according to the purpose of use by selecting the best material with specific rigidity and softness. In some preferred aspects, the elastic modulus of the substrate film (such as a flexible vinyl chloride resin film) can be above about 100MPa (generally above about 150MPa, such as above about 200MPa), and can be below about 1,000MPa (generally below about 600MPa, such as below about 300MPa). In some other aspects, the elastic modulus of the substrate film (such as an olefinic resin film) may be above about 300 MPa (generally above 400 MPa) and below about 10,000 MPa (generally below 3,000 MPa, such as below 1,000 MPa). In yet other aspects, the elastic modulus of the base film (such as a polyester resin film) may be about 500 MPa or more (generally 1,000 MPa or more, such as 3,000 MPa or more) and about 30,000 MPa or less (generally 15,000 MPa or less, such as 7,000 MPa or less).

Furthermore, the elastic modulus of the substrate film (generally a resin film) is the tensile elastic modulus calculated from the linear regression of the stress-strain curve. The stress-strain curve is to cut a test piece of a specific width from the resin film along any direction (such as MD (Machine Direction) or TD (Transverse Direction; the direction orthogonal to MD), preferably MD). and the obtained curve.

Regarding the aforementioned base film (generally, a resin film), it is preferable to use a transparent one from the viewpoint of inspectability through an adhesive sheet. Therefore, the above-mentioned resin film preferably has transparency with a total light transmittance of about 70% or more in the visible wavelength region. More preferably, it is a transparent resin film having the above-mentioned total light transmittance of 80% or more (for example, 85% or more). In addition, the upper limit of the above-mentioned total light transmittance is ideally 100%, but as long as it has a total light transmittance of about 99% or less (generally 97% or less, for example, 95% or less), it can be preferably used as a transparent resin film in practice. Regarding the value of the above-mentioned total light transmittance, the manufacturer's nominal value can be used. When there is no nominal value, the value measured according to JIS K 7361-1 can be used.

Various additives such as fillers, antioxidants, ultraviolet absorbers, antistatic components, plasticizers, lubricants, colorants (pigments, dyes, etc.) can also be formulated in the base material layer as needed. Known or customary surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and primer coating can also be performed on the surface of the adhesive layer side of the base layer. Such surface treatment may be, for example, a treatment for improving the anchoring property of the adhesive layer. In addition, when the single-sided adhesive sheet is wound up so that the surface of the adhesive layer is in contact with the back of the base layer, the back of the base layer (the side opposite to the side on which the adhesive layer is provided) may be subjected to a peeling treatment using a silicone-based, long-chain alkyl-based, fluorine-based, or other peeling treatment agent if necessary. By carrying out the peeling treatment, effects such as easy rewinding of the wound body in which the adhesive sheet is wound into a roll can be obtained.

The thickness of the base layer can be appropriately selected in consideration of the use, purpose, and use form of the adhesive sheet. In terms of workability such as strength and workability, it is usually suitable for a substrate film with a thickness of about 10 μm or more, preferably about 15 μm or more, more preferably about 20 μm or more, and more preferably 30 μm or more (for example, 35 μm or more). In addition, from the standpoint of cost and inspection, the thickness of the substrate layer is usually about 1 mm or less, preferably about 200 μm or less, preferably about 150 μm or less, more preferably about 100 μm or less, and more preferably about 75 μm or less.

＜Undercoating＞ In some aspects, a primer layer is provided on the adhesive layer side surface of the substrate layer. In other words, a primer layer is disposed between the base material layer and the adhesive layer. The undercoat layer may have a single-layer structure or a multi-layer structure of two or more layers. The material (primer) forming the undercoat layer is not particularly limited, and one or more types of urethane resin, polyester resin, acrylic resin, acrylic-urethane resin, acrylic-styrene resin, polyamide resin, melamine resin, olefin resin, polystyrene resin, epoxy resin, phenol resin, isocyanurate resin, polyvinyl acetate resin, etc. can be used. When an adhesive layer such as an acrylic system is provided on a resin film substrate, a polyester-based or urethane-based or acrylic primer is preferred, and when an acrylic adhesive layer is provided on a polyester-based substrate layer such as a PET film, a polyester-based primer is particularly preferred.

＜Conductive base coat＞ In some preferred aspects, the primer layer disposed between the substrate layer and the adhesive layer preferably contains a conductive agent. Thereby, the conductivity of the adhesive sheet can be improved, and the electrical conductivity of the adherend can be improved. Hereinafter, the undercoat layer containing a conductive agent is also referred to as a conductive undercoat layer. The conductive primer layer may have a single-layer structure or a multi-layer structure of two or more layers. In the case where a multilayer undercoat layer is disposed between the substrate layer and the adhesive layer, at least one layer (generally at least one layer including a layer in contact with the adhesive layer) is preferably a conductive undercoat layer. As the conductive agent, organic conductive substances such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, allylamine-based polymers, or metals such as gold, silver, copper, platinum, palladium, aluminum, nickel, chromium, titanium, iron, cobalt, tin, magnesium, tungsten, or alloys of these metals, metal oxides of indium, tin, zinc, gallium, antimony, zirconium, and cadmium (tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, ITO (indium oxide/tin oxide), ATO (antimony oxide/ Metal particles such as tin oxide), copper iodide, or inorganic conductive substances such as metal oxide particles and metal compound particles. As for the conductive agent, inorganic composite conductive substances formed by coating inorganic particles such as glass with metals such as silver, or organic-inorganic composite conductive substances formed by coating inorganic particles with organic materials such as conductive polymers can also be used. The above-mentioned ionic compounds can also be used. These can be used alone or two or more.

In an aspect of disposing an undercoat layer, polythiophene and polyaniline are exemplified as conductive polymers that may be contained in the undercoat layer. The polythiophene preferably has a polystyrene-equivalent Mw of 40×10 ⁴ or less, preferably 30×10 ⁴ or less. Regarding polyaniline, Mw is preferably not more than 50×10 ⁴ , preferably not more than 30×10 ⁴ . In addition, the Mw of these conductive polymers is usually preferably not less than 0.1×10 ⁴ , preferably not less than 0.5×10 ⁴ . Furthermore, the so-called polythiophene in this specification refers to a polymer of unsubstituted or substituted thiophene. As a preferred example of the substituted thiophene polymer in the technology disclosed in this case, poly(3,4-ethylenedioxythiophene) can be cited.

In some preferred aspects, the conductive primer layer may include polystyrene sulfonate (PSS) as a dopant (eg, a dopant of a thiophene-based polymer). In some aspects, the conductive undercoat layer is formed using a composition for forming an undercoat layer containing a polythiophene aqueous solution containing PSS (a form in which PSS is added as a dopant to polythiophene). The aqueous solution may contain polythiophene:PSS at a weight ratio of 1:1 to 1:10. The total content of polythiophene and PSS in the aqueous solution may be, for example, about 1 to 5% by weight. Furthermore, when using an aqueous polythiophene solution containing PSS, it is preferable to set the total amount of polythiophene and PSS to 5 parts by weight or more (usually 10 parts by weight or more, such as 25 parts by weight or more), preferably 40 parts by weight or more, relative to 100 parts by weight of the binder. In addition, the total amount of the polythiophene and PSS is preferably 200 parts by weight or less, preferably 120 parts by weight or less (for example, 100 parts by weight or less), or 80 parts by weight or less (for example, 60 parts by weight or less) relative to 100 parts by weight of the binder.

From the viewpoint of improving the conductivity, the amount of the organic conductive substance (generally a conductive polymer) used relative to 100 parts by weight of the binder contained in the primer layer can be set at least 10 parts by weight, usually more than 25 parts by weight, preferably more than 40 parts by weight. Considering the compatibility of the organic conductive substance (generally conductive polymer) in the undercoat layer and the change in characteristics such as the decrease in transparency due to the decrease in compatibility, the amount of the organic conductive substance (generally conductive polymer) should be set to 200 parts by weight or less (for example, 150 parts by weight or less) relative to 100 parts by weight of the binder, preferably 120 parts by weight or less (for example, 100 parts by weight or less). The amount of the organic conductive material (generally a conductive polymer) used may be set to 80 parts by weight or less (for example, 60 parts by weight or less) relative to 100 parts by weight of the binder.

The total amount of the conductive agent in the conductive undercoat layer (the total amount of all conductive agents including organic conductive substances, inorganic conductive substances and organic-inorganic composite conductive substances) can be set at about 5% by weight (for example, more than about 10% by weight) in the undercoat layer, preferably set at about 30% by weight or more, for example, it can also exceed 50% by weight. The upper limit of the total amount of the conductive agent in the conductive primer layer is not particularly limited, and it is preferably about 90% by weight or less (for example, 80% by weight or less), and it may be about 40% by weight or less (for example, about 30% by weight or less) in consideration of the adhesion and transparency with the base material layer or the adhesive layer.

The conductive undercoat layer may contain a binder in addition to the above-mentioned conductive agent. Regarding the binder that may be contained in the conductive undercoat layer, the above-mentioned undercoat layer forming material (undercoat agent) can be used without particular limitation. Among them, polyester-based resins are preferably used. The ratio of the binder to the entire conductive primer layer can be, for example, about 30% by weight or more, preferably about 40% by weight or more (for example, about 50% by weight or more). In addition, in consideration of electrical conductivity and the like, the ratio of the binder is preferably less than 90% by weight (less than 80% by weight).

Also, in some aspects, the primer layer contains a crosslinking agent. As for the cross-linking agent, melamine-based, isocyanate-based, epoxy-based, and other cross-linking agents generally used for cross-linking resins can be appropriately selected and used. Thereby, both the anchoring property to the base material layer and the adhesion property to the adhesive layer can be preferably achieved. In some preferred aspects, the above-mentioned cross-linking agent includes a melamine-based cross-linking agent.

The primer layer may contain additives such as antioxidants, colorants (pigments, dyes, etc.), fluidity regulators (thixotropic agents, tackifiers, etc.), film-forming aids, surfactants (defoamers, dispersants, etc.), preservatives, etc.

The undercoat layer can be formed satisfactorily by a method including drying or hardening treatment as necessary, by applying a liquid composition (coating material for undercoat layer formation) obtained by dispersing or dissolving the above-mentioned resin components and optionally additives in an appropriate solvent, using a well-known or commonly used coater such as a gravure coater or a reverse roll coater. From the viewpoint of forming a thin and uniform layer, the NV (non-volatile content) of the coating material can be set to, for example, 5% by weight or less (generally 0.05 to 5% by weight). As for the solvent that can constitute the coating material, organic solvents, water or any of these mixed solvents can also be used, preferably water or a mixed solvent mainly composed of water (such as a mixed solvent of water and ethanol).

In some other aspects, the conductive undercoat layer can be, for example, a layer composed of the above-mentioned metals or metal oxides. The conductive undercoat layer in the above aspect is preferably a metal layer such as silver or aluminum from the viewpoint of conductivity, and is preferably an ITO layer or ATO layer from the viewpoint of transparency. As for ITO, it is preferable to use one containing about 80 to 99% by weight of indium oxide and about 1 to 20% by weight of tin oxide. The metal layer or metal oxide layer as the conductive undercoat layer may be a vapor-deposited layer of a metal such as aluminum, a plated layer, or the like.

The thickness of the undercoat layer in the technique disclosed in this case is not particularly limited, and is usually about 0.01 μm or more. From the viewpoint of properly displaying the function of the undercoat layer, it is preferably set to about 0.05 μm or more, and preferably about 0.1 μm or more (for example, about 0.2 μm or more). The upper limit of the thickness of the undercoat layer is about 50 μm or less (for example, about 10 μm or less), and from the viewpoint of transparency, it is preferably about 3 μm or less, preferably about 1 μm or less (for example, about 0.6 μm or less).

＜Release liner＞ In order to protect the adhesive surface (the side of the adhesive layer attached to the adherend), the adhesive sheet disclosed in this application can be provided in the form of a release liner attached to the adhesive surface (in the form of an adhesive sheet with a release liner) as needed. There are no particular limitations on the release liner, and for example, release liners with release-treated surfaces of liner substrates such as resin films or paper, release liners made of low-adhesion materials such as fluorine-based polymers (polytetrafluoroethylene, etc.) or polyolefin-based resins (polyethylene, polypropylene, etc.), etc. can be used. In the above-mentioned release treatment, for example, release treatment agents such as silicone-based, fluorine-based, long-chain alkyl-based, fatty acid amide-based, or silica powder can be used. In some aspects, it is preferable to use a release-treated resin film (such as a polyester film) as the release liner. The thickness of the release liner can be, for example, about 5 μm to 200 μm, and usually about 10 μm to 100 μm is preferable.

＜Total thickness of adhesive sheet＞ The total thickness of the adhesive sheet disclosed in this case (which may include an adhesive layer, a substrate layer and a primer layer, but does not contain a release liner) is not particularly limited, and is preferably set in the range of about 5-1000 μm. Considering the adhesive properties, etc., the total thickness of the adhesive sheet should be set at about 10-500 μm (for example, 15-300 μm, generally 20-200 μm). In addition, from the standpoint of workability, etc., the total thickness of the adhesive sheet is preferably not less than about 30 μm, preferably not more than about 150 μm (for example, not more than 120 μm), and may be not more than about 80 μm.

＜Characteristics of Adhesive Sheet＞ Adhesive sheets of some typical aspects are characterized in that the 180-degree peeling strength (adhesion, adhesion to SUS plate) to stainless steel plates measured at 23°C at a peeling angle of 180 degrees and a speed of 300mm/min is in the range of about 0.01~4.0N/20mm. According to the adhesive sheet exhibiting the adhesive force in the above-mentioned predetermined range, adherends such as conductive small sheets can be adhered to and fixed reliably, and can be separated from the adherend well after use, thereby preventing damage to the adherend. From the viewpoint of adhesion reliability, the above-mentioned adhesive force may be greater than about 0.02N/20mm, greater than approximately 0.03N/20mm, greater than approximately 0.05N/20mm, or greater than approximately 0.08N/20mm. From the standpoint of separation and removal of the adherend, the above-mentioned adhesive force should be less than 3.0N/20mm (generally less than 2.0N/20mm, such as less than 1.0N/20mm), preferably less than about 0.5N/20mm (generally less than 0.5N/20mm, such as less than 0.3N/20mm). The above-mentioned adhesion to the SUS board can be measured by the method described in the examples described later. Furthermore, the adhesive sheet disclosed in this specification includes aspects not limited to the above-mentioned adhesive force, and in such an aspect, the adhesive sheet is not limited to those having the above-mentioned adhesive force.

The haze value of the adhesive sheet is not particularly limited, and may be, for example, about 80% or less. When inspecting the adherend through the adhesive sheet, the adhesive sheet needs moderate penetration. From this point of view, the haze value of the adhesive sheet is preferably about 50% or less (for example, about 30% or less), preferably about 10% or less, more preferably about 3% or less, and more preferably about 1% or less (for example, less than 0.1%). The haze value can be measured by the method described in the Examples described later.

＜Use＞ The application of the adhesive sheet disclosed in this case is not particularly limited, and it can be widely used in various applications of peeling off after sticking to the adherend by taking advantage of the reliability of adhesion and good separation and removal of the adherend during sticking. Regarding the above-mentioned use, a sheet for temporary fixation or a protective sheet may be exemplified. Also, for example, it can be preferably used as a process material for fixing to an adherend and peeling off in the process of electronic equipment and electronic parts.

In addition, the adhesive sheet disclosed in this case can be used as a conductive adhesive sheet for various purposes because the surface resistance value of the adhesive layer is limited to a predetermined value or less. For example, it can preferably be used as a conductive bonding member in various electronic devices. The above-mentioned conductive adhesive sheet can also be used for electromagnetic wave shielding or antistatic purposes such as electronic equipment and cables.

Some preferred adhesive sheets can be used as an adhesive sheet that detachably holds a plurality of conductive small pieces. The so-called conductive chips in this case can be metal chips, semiconductor chips, organic conductive chips, etc. used in various purposes, for example, semiconductor chips such as light-emitting semiconductor chips (generally LED chips) used in electronic products with display functions. The number of conductive small pieces configured on one adhesive sheet is 1 or more. In some aspects, the above conductive small pieces can be multiple (for example, 10 or more, further 100 or more, 1000 or more, 10,000 or more, or 100,000 or more) small pieces formed by cutting a conductive wafer. The size of each small piece is not particularly limited, for example, the size may be about 4-5 mm square or less. The adhesive sheet disclosed in this case can be arranged and fixed on the adhesive layer by arranging and fixing the above-mentioned plurality of conductive small pieces, and then electrifying all the conductive small pieces on the adhesive at the same time, and the conductive small pieces can be inspected in batches through the electrification. Therefore, the adhesive sheet disclosed in this case can also be described as an adhesive sheet for electrical inspection of conductive small pieces. The above-mentioned energization method fundamentally solves the technical and time-limited method of using probes to perform individual and full inspections, and can improve productivity while also realizing miniaturization and high performance of products. The adhesive sheet disclosed in this case has great practical advantages because it can be better used for the above purposes.

＜Inspect the manufacturing method of the conductive small piece＞ Based on the above description, according to the present specification, a manufacturing method for inspecting a completed conductive small piece (such as a semiconductor wafer) can be provided. This method can also be used as an inspection method for conductive small pieces. The above-mentioned method includes a step of preparing an adhesive sheet on which a plurality of conductive small pieces to be inspected are fixed (preparation step). In the preparation step, the above-mentioned plurality of conductive small pieces of inspection objects are detachably fixed on the surface of the adhesive layer. As for the adhesive sheet, one having a conductive adhesive layer is used. The above method further includes a step of electrifying at least a part (for example, all) of the plurality of conductive small pieces to be inspected through the adhesive layer, and inspecting the conductive small pieces to be inspected in the electrified state. According to the above-mentioned method, it is possible to carry out the simultaneous electrification inspection of the whole batch of a plurality of conductive small pieces. In addition, the above-mentioned method may further include a step of making the surfaces of the plurality of conductive small pieces to be inspected, which are opposite to the fixed surface of the adhesive layer, contact the conductive material before the inspection step. Thereby, in the inspection step, the entire batch of conductive small pieces of the inspection object can be energized through the adhesive layer and the conductive material. The details will be described below.

First, in this method, an adhesive sheet to which a plurality of conductive small pieces to be inspected is fixed is prepared (preparation step). For example, a conductive wafer is fixed on an adhesive sheet, and then the conductive wafer is processed on the adhesive sheet to form the plurality of conductive small pieces from the conductive wafer. Thereby, an adhesive sheet to which a plurality of conductive small pieces to be inspected is fixed can be prepared. As for the adhesive sheet, the adhesive sheet disclosed in this application is preferably used, but not limited thereto, and an adhesive sheet having a well-known or even commonly used conductive adhesive layer can also be used. The processing steps of conductive wafers (such as semiconductor wafers) may include the step of dicing the conductive wafer and the step of expanding the wafer. The dicing step may be, for example, a step of dividing the wafer into small pieces by dicing after laser dicing with a laser beam or the like. Then, by spreading the adhesive sheet holding the small pieces (sheet spreading step), the small pieces on the adhesive layer are arranged at predetermined intervals.

In some other aspects, the adhesive sheet on which the plurality of conductive small pieces to be inspected is fixed is prepared by transferring a plurality of conductive small pieces formed by using a well-known or even conventional adhesive sheet for cutting or an adhesive sheet for spreading to an adhesive layer of an adhesive sheet having a conductive adhesive layer. As for the conductive adhesive sheet, it is preferable to use the adhesive sheet disclosed in this case.

Then, the exposed surface (the surface opposite to the surface fixed on the adhesive layer) of the plurality of conductive small pieces to be inspected fixed on the surface of the adhesive layer of the prepared adhesive sheet is brought into contact with the conductive material. Specifically, at least a part (preferably all) of the plurality of conductive small pieces to be inspected is brought into contact with the conductive material. As for the conductive material, it is preferable to use the adhesive sheet (conductive adhesive sheet) disclosed in this case. Alternatively, well-known or even conventional conductive adhesive sheets can be used. As the conductive material, a metal plate conventionally used for conducting an electrical inspection of a semiconductor wafer or the like can also be used. The conductive material does not need to be transparent because it is usually disposed on the opposite side of the inspection surface.

Next, connect the terminals for conduction inspection such as probes to the adhesive layer of the adhesive sheet to make conduction possible, and connect a different conduction test terminal (probe, etc.) to a conductive material to make the conduction state possible, and make the current flow between the above-mentioned adhesive layer and the above-mentioned conductive material. Thereby, at least a part (preferably all) of a plurality of conductive small pieces to be inspected can be energized simultaneously and in batches. In this way, power-on inspection can be performed.

Fig. 3 is a schematic cross-sectional view illustrating the electrical inspection of the present method. In FIG. 3 , symbols 101 , 110 , and 120 represent the adhesive sheet, substrate layer, and adhesive layer (conductive adhesive layer) disclosed in this case, respectively, and symbol 201 represents a conductive material. In this embodiment, the conductive material 201 is the adhesive sheet disclosed in this application, and the conductive material (adhesive sheet) 201 has a base material layer 210 and an adhesive layer (conductive adhesive layer) 220 . The plurality of conductive small pieces 150 fixed on the surface of the adhesive layer 120 of the adhesive sheet 101, the surface opposite to the surface fixed on the adhesive layer 120 is in contact with the surface of the adhesive layer 220 of the conductive material (adhesive sheet) 201 (specifically, it is bonded and fixed). Specifically, as shown in the figure, a plurality of conductive small pieces 150 are arranged in a state of being separated from each other on the surface of the adhesive layer 120 . The surface of the plurality of conductive small pieces 150 opposite to the fixing surface of the adhesive layer 120 is covered by a conductive material (adhesive sheet) 201, whereby the two sides of each conductive small piece 150 are respectively in contact with (specifically, bonded to) the surface of the adhesive layer 120 of the adhesive sheet 101 and the surface of the adhesive layer 220 of the conductive material (adhesive sheet) 201, and can pass through the adhesive sheet 101 and the conductive material 201. The state of power on. In addition, in FIG. 3 , P is a terminal (probe) for energization inspection, and C is a camera for inspection. In addition, the conductive small pieces 150 in the figure are given symbols only for some representative ones. In addition, the conductive small piece 150 in this embodiment is a light emitting semiconductor chip, and has electrodes on both sides for contacting the adhesive layer 120, 220.

In this embodiment, although the inspection camera C is used for inspection, it is not limited thereto, and inspection by various optical inspection means or visual observation may be possible. By using an inspection mechanism such as an inspection camera C to inspect a plurality of conductive small pieces 150 that have been energized in batches at the same time through the adhesive sheet 101 (specifically, inspection of the luminous intensity or light wavelength of the light-emitting semiconductor chip), the identification and classification of defective products of the plurality of conductive small pieces 150 can be performed in batches. After the inspection, each conductive small piece is separated and removed from the adhesive sheet 101 and the conductive material 201, and then shipped as a product. Regarding other specific matters related to the above methods, since they are as described in this specification, repeated explanations are omitted.

The matters disclosed in this specification include the following. (1) An adhesive sheet having an adhesive layer, the surface resistance of the adhesive layer is 1.0×10 ⁸ Ω/□ or less, and the adhesive force to stainless steel plate is within the range of 0.01~4.0N/20mm. (2) An adhesive sheet comprising an adhesive layer, the adhesive layer comprising a polymer having an oxyalkylene structural unit, the aforementioned oxyalkylene structural unit comprising a polyoxyalkylene unit having a molar number of oxyalkylene groups greater than 2, and the aforementioned polymer comprising an oxyalkylene structural unit in a ratio of 35% by weight or more. (3) The adhesive sheet according to (1) or (2) above, which has a haze value of 50% or less. (4) The adhesive sheet according to any one of (1) to (3) above, wherein the aforementioned adhesive layer contains an oxyalkylene group structural unit. (5) The adhesive sheet according to (4) above, wherein the adhesive layer comprises a polymer having the aforementioned oxyalkylene structural unit. (6) The adhesive sheet according to (5) above, wherein the polymer having the aforementioned oxyalkylene structural unit has the aforementioned oxyalkylene structural unit in a side chain. (7) The adhesive sheet according to any one of (4) to (6) above, wherein the content ratio of the oxyalkylene group structural unit in the adhesive layer is 20 to 95% by weight. (8) The adhesive sheet according to any one of (1) to (7) above, wherein the aforementioned adhesive layer contains an ionic compound. (9) The adhesive sheet according to any one of (1) to (8) above, further comprising a base layer, and the adhesive layer is provided on at least one surface of the base layer. (10) The adhesive sheet according to (9) above, wherein the base material layer is composed of a resin film having an elastic modulus of 50 MPa or more. (11) The adhesive sheet according to (9) or (10) above, wherein a primer layer is disposed between the base material layer and the adhesive layer.

(12) A method of manufacturing an inspected conductive small piece, comprising the following steps: preparing an adhesive sheet on which a plurality of inspected conductive small pieces (such as semiconductor wafers) are fixed, wherein the adhesive sheet has a conductive adhesive layer, and the plurality of inspected conductive small pieces are detachably fixed on the surface of the adhesive layer; and A step of electrifying at least a part of the plurality of conductive small pieces to be inspected through the adhesive layer, and inspecting the conducting state of the conductive small pieces to be inspected. (13) The method according to (12) above, wherein before the inspection step, it further includes the step of contacting the surface of the plurality of conductive small pieces to be inspected that is opposite to the fixed surface of the adhesive layer with a conductive material. (14) The method according to (12) or (13) above, wherein before the step of preparing the aforementioned adhesive sheet on which the aforementioned conductive small pieces are fixed, the following steps are further included: a step of fixing a conductive wafer to the aforementioned adhesive sheet; and a step of processing the aforementioned conductive wafer to form the plurality of conductive small pieces from the conductive wafer. (15) The method according to (14) above, wherein the aforementioned step of processing the conductive wafer includes a step of dicing the conductive wafer, and may further optionally include a step of spreading the wafer. (16) The method according to (12) or (13) above, wherein the step of fixing the plurality of conductive small pieces to the adhesive sheet is included before the step of preparing the adhesive sheet on which the conductive small pieces are fixed. (17) The method according to any one of (12) to (16) above, wherein the adhesive sheet is the adhesive sheet according to any one of (1) to (11) above. (18) The method according to (13) above, wherein the conductive material is the adhesive sheet according to any one of (1) to (11) above. (19) The method according to (13) above, wherein the conductive material is a metal plate or a conductive adhesive sheet. (20) The method according to any one of (12) to (19) above, wherein the step of inspecting the conductive small piece to be inspected includes using an inspection mechanism such as a camera or visually inspecting through an adhesive sheet (such as inspection of the light-emitting state of a light-emitting semiconductor element).

(21) An adhesive composition comprising a polymer containing an oxyalkylene group structural unit, The aforementioned oxyalkylene structural unit comprises a polyoxyalkylene unit with a molar number of oxyalkylene greater than 2, The said polymer contains an oxyalkylene structural unit in the ratio of 35 weight% or more. (22) The adhesive composition according to (21) above, wherein the polymer having the aforementioned oxyalkylene structural unit has the aforementioned oxyalkylene structural unit in a side chain. (23) The adhesive composition according to (21) or (22) above, wherein the ratio of the aforementioned oxyalkylene structural unit is 20 to 95% by weight on a solid basis. (24) The adhesive composition according to any one of (21) to (23) above, which contains an ionic compound. (25) The adhesive composition according to any one of (21) to (24) above, wherein the polymer having the aforementioned oxyalkylene structural unit is an acrylic polymer.

Hereinafter, some examples related to the present invention will be described, but the present invention is not intended to be limited to these specific examples. Also, unless otherwise stated, "parts" or "%" in the following descriptions are based on weight.

＜Evaluation method＞ [adhesion] Cut the adhesive sheet into a size of 20mm width x 120mm length to make a measurement sample, and attach the measurement sample to a stainless steel plate (SUS430BA plate) that has been ultrasonically cleaned in toluene at a linear pressure of 78.5N/cm and a speed of 0.3m/min. Bonding is carried out in an atmosphere with a temperature of 23°C and 50%RH. After standing in the same environment for 30 minutes, use a tensile testing machine to peel the test sample from the stainless steel plate under the conditions of a tensile angle of 180 degrees and a speed of 0.3m/min, and measure the peel strength [N/20mm] at this time as the adhesive force. As for the tensile testing machine, the product name "AUTOGRAPH AG-IS" manufactured by Shimadzu Corporation or its equivalent can be used. In addition, when the measurement sample is a double-sided adhesive sheet (such as an adhesive sheet without a substrate), the non-measurement surface is backed with a PET film with a thickness of about 50 μm, and the measurement is carried out.

[Surface resistance value] In an atmosphere with a temperature of 23°C and 50% RH, using a resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., trade name "Loresta GX MCP-T700"), the resistance value [Ω/□] of the surface of the adhesive layer was measured under the conditions of a predetermined applied voltage (automatically adjusted for each sample) and an applied time of 30 seconds by the 4-probe method according to JIS K 7194:1994. About a measurement sample, the thing which cut the adhesive sheet into the size of 50 mm width x 50 mm length is used, for example.

[Haze value] (1) Haze value of adhesive sheet Cut the adhesive sheet into a size of 50 mm width x 50 mm length to prepare a measurement sample. The haze value (H1) of this measurement sample was measured according to JISK7136:2000 using "the haze meter HM150" manufactured by Murakami Color Technology Laboratory Co., Ltd. This haze value (H1) was made into the haze value [%] of an adhesive sheet. (2) Haze value of the adhesive layer In addition, only the substrate film used in the measurement sample was cut into a size of 50mm×50mm, and the haze value (H2) was measured in the same way as above (1), and the haze value (H3) of the adhesive layer alone was calculated from the following formula. The haze value (H3) was defined as the haze value [%] of the adhesive layer. Formula: H3=H1-H2 In the case of an adhesive sheet without a base material consisting only of an adhesive layer, measure the haze value (H1) of the one that is attached to a PET film with a thickness of about 50 μm, and measure the haze value (H2) of the PET film alone as in the case of the above-mentioned substrate film, and calculate the haze value (H3) of the adhesive layer alone from the above formula. In addition, when the calculated value is less than 0.1 [%], describe it as 0 [%].

[Preparation of Adhesive Composition] (Preparation Example A1) In a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, put methoxypolyoxyethylene (the average added molar number of ethylene oxide is 9) methacrylate/polyoxyethylene (the average added molar number of ethylene oxide is 9) methacrylate/hydroxyethyl methacrylate in a molar ratio of 80/5/15. Add 0.15 mol% of 2,2'-azobisisobutyronitrile (AIBN) and ethyl acetate as a polymerization initiator to 100 mol% of the monomer mixture, introduce nitrogen gas while stirring slowly, and carry out polymerization reaction under specific conditions to obtain polymer A1 with Mw38× ¹⁰⁴ and Mn6.5× ¹⁰⁴ .

(Preparation Example A2) As for the monomer, a monomer mixture in which the molar ratio of methoxypolyoxyethylene (average added moles of ethylene oxide: 9) methacrylate/polyoxyethylene (average added moles of ethylene oxide: 9) methacrylate/hydroxyethyl methacrylate/methyl methacrylate was 65/5/10/20 was used. The rest were the same as Preparation Example A1 to obtain Polymer A2.

(Preparation Example A3) As the monomer, a monomer mixture in which the molar ratio of methoxypolyethylene (average added moles of ethylene oxide: 9) methacrylate/polyoxyethylene (average added moles of ethylene oxide: 9) methacrylate/hydroxyethyl methacrylate/methyl methacrylate was 45/5/10/40 was used. For the rest, the same method as Preparation Example A1 was used to obtain Polymer A3.

(Preparation Example A4) As a monomer, a monomer mixture in which the molar ratio of polyoxyethylene (average addition molar number of ethylene oxide: 9) methacrylate/hydroxyethyl methacrylate was 80/20 was used. For the rest, the same method as in Preparation Example A1 was used to obtain Polymer A4.

(Preparation Example A5) As the monomer, a monomer mixture in which the molar ratio of polyoxyethylene (average addition molar number of ethylene oxide: 9) methacrylate/hydroxyethyl methacrylate/methyl methacrylate was 60/20/20 was used. The rest were the same as in Preparation Example A1 to obtain Polymer A5.

[Making of base material] (Manufacturing example B1) An aqueous solution (manufactured by Bytron P, H.C. Stark) containing 0.5% of poly(3,4-ethylenedioxythiophene) (PEDOT) and 0.8% of polystyrene sulfonate (number average molecular weight: 150,000) (PSS) was prepared as a conductive polymer. Also, prepare a dispersion containing 25% polyester resin as a binder (manufactured by Toyobo Co., Ltd., trade name "Vylonal MD-1480" (aqueous dispersion of saturated copolyester resin). In a mixed solvent of water and ethanol, add 100 parts of the above-mentioned binder dispersion in terms of solid content, 50 parts of the above-mentioned conductive polymer aqueous solution in terms of solid content, and 5 parts of a melamine-based crosslinking agent, and stir for about 20 minutes. 4% of the composition for forming a conductive undercoat layer. The composition for forming a conductive undercoat layer was coated on one side of a PET film (elastic modulus 4.2 GPa) with a thickness of 50 μm, and dried at 120° C. for 60 seconds to form a conductive undercoat layer with a thickness of 300 nm. In this way, a substrate film B1 with a conductive undercoat layer was obtained.

(Manufacturing example B2) Instead of the PET film, a polyvinyl chloride film with a thickness of 70 μm (dioctyl terephthalate is used as the plasticizer, and the modulus of elasticity is 250 MPa) is used as the base material. The rest is the same method as Production Example B1 to obtain the substrate film B2 with conductive primer layer.

(Manufacturing example B3) Instead of the PET film, a multi-layer strong extruded film (elastic modulus 600 MPa) of polypropylene/polyethylene-vinyl acetate copolymer with a thickness of 100 μm was used as the substrate. The rest is the same method as Production Example B1 to obtain the substrate film B3 with conductive primer layer.

(Manufacturing example B4) Instead of the PET film, a polypropylene/polyethylene hybrid film (elastic modulus 600 MPa) with a thickness of 40 μm was used as the base material. The rest is the same method as Production Example B1 to obtain the substrate film B4 with conductive primer layer.

<Example 1> Prepare an ethyl acetate solution containing 85 parts of polymer A1, 2.5 parts of an isocyanate-based crosslinking agent ("CORONATE HX" manufactured by Tosoh Corporation), 15 parts of lithium bis(trifluoromethanesulfonyl)imide (trade name "FTOP EF-N115" manufactured by Mitsubishi Materials Corporation), and 0.016 parts of an adhesive such as iron acetylacetonate ("NASEM Iron" manufactured by Nippon Chemical Industry Co., Ltd.) Adhesive composition. The adhesive composition was coated on the surface of the conductive primer layer of the substrate film B1 with a conductive primer layer, and dried at 130° C. for 90 seconds to form an adhesive layer with a thickness of 10 μm. Thereby, the single-sided adhesive adhesive sheet of this example was obtained.

＜Example 2~5＞ Except using Polymer A2 (Example 2), Polymer A3 (Example 3), Polymer A4 (Example 4) or Polymer A5 (Example 5) instead of Polymer A1, the adhesive composition of each example was prepared in the same way as in Example 1. Except for using these adhesive compositions, the same method as Example 1 was used to obtain a single-sided adhesive adhesive sheet for each example.

<Example 6> Except for preparing the adhesive composition of Example 2 and using the substrate film B2 with a conductive primer layer, the above-mentioned adhesive composition was coated on the surface of the conductive primer layer of the substrate film B2 with a conductive primer layer in the same manner as in Example 2 and dried to obtain the single-sided adhesive adhesive sheet of this example.

＜Example 7~8＞ Except for preparing the adhesive composition of Example 1 and using the substrate film B3 (Example 7) or B4 (Example 8) with a conductive primer layer, the above-mentioned adhesive composition was coated on the surface of the conductive primer layer of the substrate film with a conductive primer layer in the same manner as in Example 1 and dried to obtain a single-sided adhesive adhesive sheet of each example.

<Example 9> 85 parts of polyether polyol A ("PREMINOL S 3011" manufactured by AGC, molecular weight 10000), 13 parts of polyether polyol B ("SANNIX GP-3000" manufactured by Sanyo Chemical Co., Ltd., polyoxypropylene glyceryl ether, number average molecular weight 3000), polyether polyol C ("SANNIX GP-1000" manufactured by Sanyo Chemical Industry Co., Ltd., polyoxypropylene glyceryl ether, number average molecular weight 1 000) 2 parts, polyfunctional isocyanate crosslinking agent ("CORONATE HX" manufactured by Tosoh Corporation) 18 parts, lithium bis(trifluoromethanesulfonyl)imide (trade name "FTOP EF-N115" manufactured by Mitsubishi Materials Corporation) 15 parts and acetylacetonate iron ("NASEM iron" manufactured by Nippon Chemical Industry Co., Ltd. "NASEM Iron") 0.12 parts of ethyl acetate solution prepared as the adhesive in this example Composition. The adhesive composition was coated on the surface of the conductive primer layer of the substrate film B1 with a conductive primer layer, and hardened at 130° C. for 90 seconds to form an adhesive layer with a thickness of 10 μm. Thereby, the single-sided adhesive adhesive sheet of this example was obtained.

<Example 10> Prepare an ultraviolet (UV) curable slurry in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet pipe, and a cooler as the adhesive composition of this example. The ultraviolet (UV) curable slurry is composed of 82 parts of 2-ethylhexyl acrylate, 12 parts of N-vinylpyrrolidone, 3 parts of 4-hydroxyethyl acrylate, 3 parts of acrylic acid, and a photoinitiator ("Omnirad651" manufactured by IGM Resins Itaria Srl). .05 parts, 0.1 parts of anti-aging agent ("Songnox1010"), 0.05 parts of crosslinking agent ("NK ester A-HD-N" manufactured by Shin Nakamura Chemical Industry Co., Ltd.), 50 parts of conductive filler ("Sil-shield Ag/glass 5/25s" manufactured by ECKA Corporation), and 150 parts of conductive filler ("TP25S12" manufactured by Potters Corporation). The adhesive composition was coated on the release layer of the polyester film with agglomerated silicone release layer, and then bonded with the polyester film with agglomerated silicone release layer, and irradiated with UV with an illumination intensity of 50mW/ ^cm2 for 5 minutes to make it harden. Thereby, the substrate-less double-sided adhesive sheet which consists of an adhesive layer of thickness 30 micrometers was obtained.

<Example 11> Except changing the thickness of the adhesive layer to 50 μm, the same method as in Example 10 was used to obtain the substrate-free double-sided adhesive sheet of this example.

Table 1 shows the general composition, adhesive force [N/20mm], surface resistance value [Ω/□] and haze value [%] of the adhesive sheet of each example.

[Table 1]

As shown in Table 1, the adhesive sheets of Examples 1 to 9 have a surface resistance value of 10 ⁸ Ω/□ or less, so a plurality of conductive small pieces (such as semiconductor chips) arranged on the adhesive can be simultaneously energized in batches through the adhesive layer. In addition, since the adhesive sheet of these examples is in the range of 0.01 to 4.0 N/20mm in the adhesive force to the SUS board, the conductive small piece can be reliably fixed, and the conductive small piece can be separated from the surface of the adhesive layer well after the electrification step is completed. On the other hand, although the adhesive sheets of Examples 10-11 have good electrical conductivity, the adhesive force exceeds 4.0N/20mm, and compared with Examples 1-9, it is considered that the separation and removal of the adherend is inferior. Moreover, the haze value also exceeded 50%, and it was considered that the inspection through the adhesive sheet was impossible or the inspection property was poor. From the above results, the adhesive sheet with the surface resistance value of the adhesive layer below 10 ⁸ Ω/□ and the adhesive force to the SUS board within the range of 0.01~4.0N/20mm is suitable for the simultaneous inspection of multiple conductive small pieces.

Specific examples of the present invention have been described in detail above, but these specific examples are merely illustrations and are not intended to limit the scope of claims. The techniques described in the scope of claims include various modifications and changes of the specific examples exemplified above.

1,2,101,201: Adhesive sheet 10, 110, 210: substrate layer 10A: One side of the substrate layer (the first side) 10B: The other side of the substrate layer 20, 120, 220: Adhesive layer 20A: The surface of the adhesive layer (adhesive surface) 30: Base coat 30A: The other side of the base coat 30B: One side of the base coat 150: conductive small piece 201: Conductive material C: camera for inspection P: Terminal for power-on inspection

Fig. 1 is a schematic cross-sectional view showing a configuration example of an adhesive sheet according to an embodiment. Fig. 2 is a schematic cross-sectional view showing a configuration example of an adhesive sheet according to another embodiment. FIG. 3 is a schematic cross-sectional view illustrating an electrical inspection of a conductive small piece according to an embodiment.

1: Adhesive sheet

10: Substrate layer

10A: One side of the substrate layer (the first side)

10B: The other side of the substrate layer

20: Adhesive layer

20A: The surface of the adhesive layer (adhesive surface)

Claims (25)

An adhesive sheet having an adhesive layer, the surface resistance of the adhesive layer is 1.0×10 ⁸ Ω/□ or less, the adhesive force of the adhesive sheet to the stainless steel plate is in the range of 0.01-4.0N/20mm, and the haze value is 50% or less. The adhesive sheet according to claim 1, wherein the adhesive layer contains an oxyalkylene structural unit. The adhesive sheet according to claim 2, wherein the aforementioned adhesive layer comprises a polymer having the aforementioned oxyalkylene structural unit. The adhesive sheet according to claim 3, wherein the polymer having the aforementioned oxyalkylene structural unit has the aforementioned oxyalkylene structural unit in the side chain. The adhesive sheet according to any one of claims 2 to 4, wherein the content ratio of the aforementioned oxyalkylene group structural unit in the aforementioned adhesive layer is 20 to 95% by weight. The adhesive sheet according to any one of claims 1 to 4, wherein the adhesive layer contains an ionic compound. The adhesive sheet according to claim 5, wherein the adhesive layer contains an ionic compound. The adhesive sheet according to any one of claims 1 to 4, further comprising a substrate layer, and the adhesive layer is provided on at least one side of the substrate layer. The adhesive sheet according to claim 5, further comprising a substrate layer, and the adhesive layer is provided on at least one side of the substrate layer. The adhesive sheet according to claim 6, further comprising a substrate layer, and the adhesive layer is provided on at least one side of the substrate layer. Such as the adhesive sheet of claim 7, which further has a substrate layer, and the aforementioned adhesive layer is It is arranged on at least one side of the substrate layer. The adhesive sheet according to claim 8, wherein the base material layer is made of a resin film with an elastic modulus of 50 MPa or more. The adhesive sheet according to claim 9, wherein the base material layer is made of a resin film with an elastic modulus of 50 MPa or more. The adhesive sheet according to claim 10, wherein the base material layer is made of a resin film with an elastic modulus of 50 MPa or more. The adhesive sheet according to claim 11, wherein the base material layer is made of a resin film with an elastic modulus of 50 MPa or more. The adhesive sheet according to claim 8, wherein a primer layer is disposed between the base material layer and the adhesive layer. The adhesive sheet according to claim 9, wherein a primer layer is disposed between the base material layer and the adhesive layer. The adhesive sheet according to claim 10, wherein a primer layer is disposed between the base material layer and the adhesive layer. The adhesive sheet according to claim 11, wherein a primer layer is arranged between the base material layer and the adhesive layer. The adhesive sheet according to claim 12, wherein a primer layer is disposed between the base material layer and the adhesive layer. The adhesive sheet according to claim 13, wherein a primer layer is disposed between the base material layer and the adhesive layer. The adhesive sheet according to claim 14, wherein a primer layer is disposed between the base material layer and the adhesive layer. The adhesive sheet according to claim 15, wherein the base material layer and the adhesive layer An undercoat layer is arranged in between. A method of manufacturing an inspected conductive small piece, comprising the following steps: preparing an adhesive sheet on which a plurality of inspection object conductive small pieces are fixed, wherein the adhesive sheet has a conductive adhesive layer, and the plurality of inspection object conductive small pieces are detachably fixed on the surface of the adhesive layer; and electrifying at least a part of the aforementioned plurality of inspection object conductive small pieces through the adhesive layer, and checking the electrified state of the inspection object conductive small piece. The method according to claim 24, wherein before the inspection step, it further includes the step of making the surfaces of the plurality of conductive small pieces to be inspected which are opposite to the fixed surface of the adhesive layer contact the conductive material.

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