Method for arranging thermoelectric conversion material chips

Abstract

Provided is a method for efficiently arraying a chip of a P-type thermoelectric conversion material and a chip of an N-type thermoelectric conversion material collectively on a support. A method for arraying chips of a thermoelectric conversion material is provided, in which the chips of the thermoelectric conversion material include a chip of a P-type thermoelectric conversion material and a chip of an N-type thermoelectric conversion material, the method comprising steps (A) to (J) (see the Description).

Description

[Technical Field]

[0001] The present invention relates to a method for arranging chips of thermoelectric conversion material. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there have been thermoelectric conversion modules that use thermoelectric conversion materials having thermoelectric effects such as the Seebeck effect and the Peltier effect to convert thermal energy into electrical energy and vice versa. The use of so-called π-type thermoelectric conversion elements is known as the thermoelectric conversion module. A π-type thermoelectric conversion element is a basic unit in which a pair of electrodes spaced apart from each other are provided on a substrate. For example, the lower surface of a P-type thermoelectric element is provided on one electrode, and the lower surface of an N-type thermoelectric element is provided on the other electrode, also spaced apart from each other. The upper surfaces of the two types of thermoelectric elements are connected to electrodes on the opposing substrates. Typically, multiple such basic units are configured to be electrically connected in series within both substrates. Also known is the use of so-called in-plane type thermoelectric conversion elements. In-plane type thermoelectric conversion elements are configured by alternately providing P-type and N-type thermoelectric elements in the in-plane direction of the substrate, and electrically connecting the lower portions of the junctions between the two thermoelectric elements via electrodes, for example.

[0003] Thus, when constructing a π-type thermoelectric conversion element and an in-plane type thermoelectric conversion element, it is necessary to arrange P-type thermoelectric elements and N-type thermoelectric elements alternately in a predetermined pattern. To meet these requirements, Patent Document 1 discloses a method of arranging rectangular parallelepiped P-type semiconductor elements and N-type semiconductor elements that constitute a π-type Peltier module so that they are alternately connected with electrodes interposed therebetween. Patent Document 2 discloses a method for manufacturing a π-type thermoelectric conversion module, in which both longitudinal ends of P-type thermoelectric conversion elements and N-type thermoelectric conversion elements in the form of square timbers are inserted into respective lattice windows of a pair of lattice-shaped jigs so that the P-type thermoelectric conversion elements and the N-type thermoelectric conversion elements alternate, and then a resin material is filled in the gaps between the P-type thermoelectric conversion elements and the N-type thermoelectric conversion elements by a predetermined method to form an integrated block, which is then cut to a predetermined thickness using a cutting machine, thereby arranging multiple pairs of P-type thermoelectric conversion elements and N-type thermoelectric conversion elements. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-031859 [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-161297 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, it is necessary to individually prepare multiple pairs of rectangular parallelepiped P-type and N-type semiconductor elements in advance and then arrange them one by one alternately on the electrodes, which is cumbersome, time-consuming, and not productive.In Patent Document 2, although the alternately arranged P-type and N-type thermoelectric conversion elements and the alternately arranged P-type and N-type thermoelectric conversion elements are integrated into a block molded body in the final step by cutting, it is necessary to individually prepare multiple pairs of P-type and N-type thermoelectric conversion elements in the form of square timber in advance, and there are many cumbersome and time-consuming steps, such as inserting the P-type and N-type thermoelectric conversion elements one by one into a grid-shaped jig so that they are arranged alternately, which is not sufficient from the perspective of productivity.

[0006] In view of the above, an object of the present invention is to provide a method for efficiently arranging chips of P-type thermoelectric conversion material and chips of N-type thermoelectric conversion material together on a support. [Means for solving the problem]

[0007] As a result of extensive research into solving the above-mentioned problems, the inventors have found that the above-mentioned problems can be solved by using a method in which a P-type thermoelectric conversion material layer on a fixing layer on a first support is singulated into a plurality of P-type thermoelectric conversion material chips, the adhesive strength of the fixing layer in an area where some of the P-type thermoelectric conversion material chips are attached, and selectively transferring only some of the P-type thermoelectric conversion material chips onto the fixing layer on a second support, or a method in which a similar operation is applied to an N-type thermoelectric conversion material layer on a fixing layer on a third support, and selectively transferring only some of the N-type thermoelectric conversion material chips onto the fixing layer on a fourth support, and bonding together respective supports having the separated P-type thermoelectric conversion material chips or separated N-type thermoelectric conversion material chips that are the originals of the transferred chips so that the P-type thermoelectric conversion material chips and the N-type thermoelectric conversion material chips are arranged alternately on the same plane, thereby completing the present invention. That is, the present invention provides the following [1] to

[10] . [1] A method for arranging chips of thermoelectric conversion material, the chips of thermoelectric conversion material including chips of P-type thermoelectric conversion material and chips of N-type thermoelectric conversion material, (A) a step of attaching a P-type thermoelectric conversion material layer to a fixing layer on a first support; (B) a step of singulating the P-type thermoelectric conversion material layer attached to the fixing layer on the first support into P-type thermoelectric conversion material chips to obtain a plurality of P-type thermoelectric conversion material chips; (C) reducing the adhesive strength between some of the P-type thermoelectric conversion material chips and the fixing layer; (D) peeling off the part of the P-type thermoelectric conversion material chips whose adhesive strength to the fixing layer has decreased from the fixing layer on the first support, and transferring and attaching the surface of the part of the P-type thermoelectric semiconductor chips opposite to the attachment surface to the fixing layer on a second support; (E) a step of attaching the N-type thermoelectric conversion material layer to a fixing layer on a third support; (F) a step of singulating the N-type thermoelectric conversion material layer attached to the fixing layer on the third support into N-type thermoelectric conversion material chips to obtain a plurality of N-type thermoelectric conversion material chips; (G) reducing the adhesive strength between some of the N-type thermoelectric conversion material chips and the fixing layer; (H) peeling off the chips of the part of the N-type thermoelectric conversion material whose adhesive strength to the fixing layer has decreased from the fixing layer on the third support, and transferring and attaching the surface opposite to the attachment surface of the chips of the part of the N-type thermoelectric conversion material to the fixing layer on a fourth support; (I) a step of attaching a surface opposite to the attachment surface of the chips of the P-type thermoelectric conversion material, whose adhesive strength with the fixing layer has been maintained in the step (D), to the fixing layer between the chips of the part of the N-type thermoelectric conversion material attached to the fixing layer on the fourth support obtained in the step (H); (J) a step of attaching a surface opposite to the attachment surface of the chips of N-type thermoelectric conversion material, whose adhesive strength with the fixing layer has been maintained in the step (H), to the fixing layer between the chips of the part of P-type thermoelectric conversion material attached to the fixing layer on the second support obtained in the step (D); A method for arranging chips of thermoelectric conversion material, comprising: [2] The method for arranging chips of thermoelectric conversion material according to [1] above, wherein the fixing layer is a fixing layer capable of absorbing laser light, and the steps (C) and (G) are carried out by irradiating the laser light, in this order, to at least a part of the fixing layer in each region where the part of the P-type thermoelectric conversion material chips and the part of the N-type thermoelectric conversion material chips are attached. [3] The method for arranging chips of thermoelectric conversion material according to [1] or [2] above, wherein the fixing layer includes an adhesive layer. [4] The method for arranging chips of thermoelectric conversion material according to [2] above, wherein the fixing layer capable of absorbing laser light is an adhesive layer containing a colorant or a metal filler. [5] The method for arranging chips of a thermoelectric conversion material according to any one of the above [1] to [4], wherein the support is made of a resin film. [6] The method for arranging chips of thermoelectric conversion material according to [1] above, wherein a thermally expandable substrate is used as the support in one or both of the steps (C) and (G). [7] The method for arranging chips of thermoelectric conversion material according to [1] above, wherein in one or both of the steps (C) and (G), the fixing layer contains thermally expandable particles. [8] The method for arranging chips of thermoelectric conversion material according to any one of [1] to [7] above, wherein the chips of thermoelectric conversion material are made of a thermoelectric semiconductor composition, and the thermoelectric semiconductor composition contains a thermoelectric semiconductor material, a resin, and one or both of an ionic liquid and an inorganic ionic compound. [9] A method for producing a chip array of thermoelectric conversion material, comprising a step of carrying out the method according to any one of [1] to [8] above.

[10] A method for producing a thermoelectric conversion module containing chips of a thermoelectric conversion material, comprising a step of carrying out the method according to any one of the above [1] to [8]. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a method for efficiently arranging chips of P-type thermoelectric conversion material and chips of N-type thermoelectric conversion material together on a support. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing one embodiment of a step of a method for arranging chips of a thermoelectric conversion material according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing one embodiment of the adhesive strength reducing step in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Method of arranging thermoelectric conversion material chips] The method for arranging chips of thermoelectric conversion material of the present invention is a method for arranging chips of thermoelectric conversion material, wherein the chips of thermoelectric conversion material include chips of P-type thermoelectric conversion material and chips of N-type thermoelectric conversion material, (A) a step of attaching a P-type thermoelectric conversion material layer to a fixing layer on a first support; (B) a step of singulating the P-type thermoelectric conversion material layer attached to the fixing layer on the first support into P-type thermoelectric conversion material chips to obtain a plurality of P-type thermoelectric conversion material chips; (C) reducing the adhesive strength between some of the P-type thermoelectric conversion material chips and the fixing layer; (D) peeling off the part of the P-type thermoelectric conversion material chips whose adhesive strength to the fixing layer has decreased from the fixing layer on the first support, and transferring and attaching the surface of the part of the P-type thermoelectric semiconductor chips opposite to the attachment surface to the fixing layer on a second support; (E) a step of attaching the N-type thermoelectric conversion material layer to a fixing layer on a third support; (F) a step of singulating the N-type thermoelectric conversion material layer attached to the fixing layer on the third support into N-type thermoelectric conversion material chips to obtain a plurality of N-type thermoelectric conversion material chips; (G) reducing the adhesive strength between some of the N-type thermoelectric conversion material chips and the fixing layer; (H) peeling off the chips of the part of the N-type thermoelectric conversion material whose adhesive strength to the fixing layer has decreased from the fixing layer on the third support, and transferring and attaching the surface opposite to the attachment surface of the chips of the part of the N-type thermoelectric conversion material to the fixing layer on a fourth support; (I) a step of attaching a surface opposite to the attachment surface of the chips of the P-type thermoelectric conversion material, whose adhesive strength with the fixing layer has been maintained in the step (D), to the fixing layer between the chips of the part of the N-type thermoelectric conversion material attached to the fixing layer on the fourth support obtained in the step (H); (J) a step of attaching a surface opposite to the attachment surface of the chips of N-type thermoelectric conversion material, whose adhesive strength with the fixing layer has been maintained in the step (H), to the fixing layer between the chips of the part of P-type thermoelectric conversion material attached to the fixing layer on the second support obtained in the step (D); The present invention is characterized in that it includes: The method for arranging thermoelectric conversion material chips of the present invention involves singulating a P-type thermoelectric conversion material layer on a fixing layer on a substrate into multiple P-type thermoelectric conversion material chips, reducing the adhesive strength of the fixing layer in areas where some of the P-type thermoelectric conversion material chips are attached, selectively transferring only some of the P-type thermoelectric conversion material chips onto the fixing layer on another substrate, independently performing a similar operation on an N-type thermoelectric conversion material layer on the fixing layer on another substrate, selectively transferring only some of the N-type thermoelectric conversion material chips onto the fixing layer on yet another substrate, and then using the resulting substrates bearing the spaced P-type thermoelectric conversion material chips or N-type thermoelectric conversion material chips, bonding them together so that the P-type thermoelectric conversion material chips and the N-type thermoelectric conversion material chips are arranged alternately, for example. This allows multiple P-type thermoelectric conversion material chips and N-type thermoelectric conversion material chips to be arranged alternately on a single support, making it possible to easily mass-produce π-type thermoelectric conversion elements and in-plane thermoelectric conversion elements. This simplifies the manufacturing process, shortening the takt time and improving yield, which is expected to reduce costs.

[0011] In the following explanation, the respective steps (A), (B), (C), (D), (E), (F), (G), (H), (I), and (J) may be referred to, in this order, as the "(A) P-type thermoelectric conversion material layer adhering step," "(B) P-type thermoelectric conversion material chip forming step," "(C) adhesive strength reducing step," "(D) P-type thermoelectric conversion material chip transferring step," "(E) N-type thermoelectric conversion material layer adhering step," "(F) N-type thermoelectric conversion material chip forming step," "(G) adhesive strength reducing step," "(H) N-type thermoelectric conversion material chip transferring step," "(I) thermoelectric conversion material chip bonding step," and "(J) thermoelectric conversion material chip bonding step." They may also be simply referred to as "(A) step," "(B) step," "(C) step," "(D) step," "(E) step," "(F) step," "(G) step," "(H) step," "(I) step," and "(J) step." Furthermore, "chips of P-type thermoelectric conversion material and chips of N-type thermoelectric conversion material" may also be simply referred to as "chips of thermoelectric conversion material."

[0012] FIG. 1 is a schematic cross-sectional view showing one embodiment of a step of a method for arranging chips of a thermoelectric conversion material according to one embodiment of the present invention; 1(a) is a cross-sectional view of a first support 1a after a P-type thermoelectric conversion material layer 3p is attached to a fixing layer 2 on the first support 1a; 1B is a cross-sectional view after the P-type thermoelectric conversion material layer 3p is singulated into P-type thermoelectric conversion material chips 3pt to form a plurality of P-type thermoelectric conversion material chips 3pt; 1(c) is a cross-sectional view showing an aspect after the adhesive strength between some of the P-type thermoelectric semiconductor chips 3pt and the fixing layer 2 among the multiple P-type thermoelectric conversion material chips 3pt formed in FIG. 1(b) has been reduced (the space between the fixing layer 2 and the P-type thermoelectric conversion material chips 3pt is exaggerated); (d) is a cross-sectional view after some of the P-type thermoelectric semiconductor chips 3pt, whose adhesive strength with the fixing layer 2 has decreased, have been peeled off from the fixing layer 2 on the second support 1b, and the surface opposite to the adhesive surface of some of the P-type thermoelectric semiconductor chips 3pt has been transferred and attached to the fixing layer 2 on the second support 1b. FIG. 1(e) is a cross-sectional view of the third support 1c after the N-type thermoelectric conversion material layer 3n is attached to the fixing layer 2. 1(f) is a cross-sectional view after the N-type thermoelectric conversion material layer 3n is singulated into N-type thermoelectric conversion material chips 3nt to form a plurality of N-type thermoelectric conversion material chips 3nt; 1(g) is a cross-sectional view showing an aspect after the adhesive strength between some of the N-type thermoelectric semiconductor chips 3nt and the fixing layer 2 among the multiple N-type thermoelectric conversion material chips 3nt formed in (f) has been reduced (the space between the fixing layer 2 and the N-type thermoelectric conversion material chips 3nt is exaggerated); (h) is a cross-sectional view after some of the N-type thermoelectric semiconductor chips 3nt, whose adhesive strength with the fixing layer 2 has decreased, have been peeled off from the fixing layer 2 on the third support 1c, and the surface opposite to the adhesive surface of some of the N-type thermoelectric semiconductor chips 3nt has been transferred and attached to the fixing layer 2 on the fourth support 1d. 1(i) is a cross-sectional view showing an embodiment in which a surface opposite to the attachment surface of the chip 3pt of the P-type thermoelectric conversion material, whose adhesive strength with the fixing layer 2 is maintained in (d), is attached to the fixing layer 2 between the chips of the N-type thermoelectric conversion material attached to the fixing layer 2 on the fourth support 1d obtained in (h); (j) is a cross-sectional view showing an embodiment in which the surface opposite to the adhesive surface of the chips 3nt of N-type thermoelectric conversion material, whose adhesive strength with the fixing layer 2 is maintained in (h), is attached to the fixing layer 2 between some of the chips 3pt of P-type thermoelectric conversion material attached to the fixing layer on the second support 1b obtained in (d). (i') is a cross-sectional view showing the state after chips 3nt of N-type thermoelectric conversion material and chips 3pt of P-type thermoelectric conversion material are alternately arranged on the fixing layer 2 on the fourth support 1d in (i), and then the fixing layer 2 having the first support 1a is peeled off from them. (j') is a cross-sectional view showing the state after chips 3pt of P-type thermoelectric conversion material and chips 3nt of N-type thermoelectric conversion material are alternately arranged on the fixing layer 2 on the second support 1b in (j), and then the fixing layer 2 having the third support 1c is peeled off from them.

[0013] ·Thermoelectric conversion material layer adhesion process The method of arranging chips of thermoelectric conversion material of the present invention includes (A) a P-type thermoelectric conversion material layer adhering step, and (E) an N-type thermoelectric conversion material layer adhering step. The thermoelectric conversion material layer adhering step is a step of adhering a thermoelectric conversion material layer to a fixing layer on a support, for example, in Fig. 1(a), it is a step of adhering a P-type thermoelectric conversion material layer 3p to the fixing layer 2 on the first support 1a [step (A)]. Similarly, in Fig. 1(e), it is a step of adhering an N-type thermoelectric conversion material layer 3n to the fixing layer 2 on the third support 1c [step (E)].

[0014] <Support> The support used in the present invention is not particularly limited, but examples of the main material include resin, glass, ceramics, silicon, and the like. In one embodiment, a resin film having optical transparency and containing a resin-based material as a main component is preferred. Specific examples of resin films include polyethylene films such as low-density polyethylene (LDPE) film, linear low-density polyethylene (LLDPE) film, and high-density polyethylene (HDPE) film, polyolefin films such as polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norbornene resin film; ethylene copolymer films such as ethylene-vinyl acetate copolymer film, ethylene-(meth)acrylic acid copolymer film, and ethylene-(meth)acrylic acid ester copolymer film; polyvinyl chloride films such as polyvinyl chloride film and vinyl chloride copolymer film; polyester films such as polyethylene terephthalate film and polybutylene terephthalate film; polyurethane films; polyimide films; polystyrene films; polycarbonate films; fluororesin films, etc. Modified films such as crosslinked films and ionomer films of these may also be used. The support may be one of these resin films, or a laminate film using two or more of them in combination.

[0015] Here, from the viewpoints of versatility, relatively high strength that makes it easy to prevent warping, heat resistance, and improved laser light transmittance (described later), the resin film is preferably a polyethylene film such as a low-density polyethylene (LDPE) film, a linear low-density polyethylene (LLDPE) film, or a high-density polyethylene (HDPE) film, a polyester film such as a polyethylene terephthalate film or a polybutylene terephthalate film, or a polypropylene film. Specifically, the resin film is preferably a monolayer film having one or more layers selected from the group consisting of a polyethylene film, a polyester film, and a polypropylene film, or a laminate film having two or more layers laminated together. In order to ensure high light transmittance for light of a desired wavelength, it is preferable to enhance the smoothness of the surface of the support opposite to the surface on which the fixing layer (described later) is formed, and the arithmetic mean roughness Ra is preferably 0.01 μm to 0.80 μm. The arithmetic mean roughness Ra is a value measured in accordance with JIS B 0601:1994.

[0016] The support may contain a colorant, but when laser light is used in the adhesive strength reducing steps (C) and (G) described below, the content of components such as colorants that absorb laser light is preferably small from the viewpoint of obtaining a support with superior laser light transmittance. Specifically, the content of colorants that absorb laser light is preferably less than 0.1% by mass, more preferably less than 0.01% by mass, even more preferably less than 0.001% by mass, based on the total mass of the support, and even more preferably the support does not contain any components that absorb the wavelength of the laser light used.

[0017] Furthermore, in another embodiment, it is preferable to use a thermally expandable substrate as the support, for example, in one or both of the adhesive strength reducing steps (C) and (G) described below, which are adhesive strength reducing steps described below, when the adhesive strength between the adhesive layer described below and the thermoelectric conversion material chip is to be reduced.

[0018] The thermally expandable substrate is a non-stick substrate containing a resin and thermally expandable particles. Examples of the resin include acrylic urethane resins and olefin resins. The thermally expandable particles are preferably microencapsulated foaming agents that are composed of an outer shell made of a thermoplastic resin and an encapsulated component that is encapsulated in the outer shell and vaporizes when heated to a predetermined temperature. Examples of thermoplastic resins that form the outer shell of the microencapsulated foaming agent include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Examples of the encapsulated components encapsulated in the outer shell include propane, butane, pentane, hexane, heptane, octane, nonane, decane, and isobutane. These encapsulation components may be used alone or in combination of two or more.

[0019] The average particle size of the thermally expandable particles at 23° C. before expansion is preferably 3 to 100 μm, more preferably 4 to 70 μm, even more preferably 6 to 60 μm, and still more preferably 10 to 50 μm. The average particle size of the thermally expandable particles before expansion is the volume median particle size (D50), and refers to the particle size corresponding to a cumulative volume frequency of 50%, calculated from the smaller particle size of the thermally expandable particles before expansion, in the particle distribution of the thermally expandable particles before expansion measured using a laser diffraction particle size distribution analyzer (for example, Malvern, product name "Mastersizer 3000").

[0020] The thickness of the support is not particularly limited, but is preferably in the range of 20 μm to 450 μm, more preferably 25 μm to 400 μm.

[0021] <Fixed layer> The fixing layer used in the present invention adheres the support to the thermoelectric conversion material layer or the chips of the thermoelectric conversion material layer, and also serves the function of selectively reducing the adhesive strength between some of the multiple thermoelectric conversion material chips and the thermoelectric conversion material chips through the physicochemical action described below. As long as the above requirements are satisfied, the fixing layer can be a layer containing a thermosetting resin, a photocurable resin, or the like. In one embodiment, it is preferable to use a pressure-sensitive adhesive layer. In another embodiment, from the viewpoints of adhesiveness and light absorption, it is preferable to use a pressure-sensitive adhesive layer containing a colorant or a metal filler. Furthermore, in another embodiment, from the viewpoints of chip retention and transferability of the thermoelectric conversion material, it is preferable to use a pressure-sensitive adhesive layer containing an energy ray-curable pressure-sensitive adhesive resin having a polymerizable functional group introduced into its side chain. In still another embodiment, from the viewpoint of ease of peeling off the thermoelectric conversion material chip, the pressure-sensitive adhesive layer preferably contains the thermally expandable particles.

[0022] The adhesive layer may contain any adhesive resin, and may contain adhesive additives such as a crosslinking agent, a tackifier, a polymerizable compound, and a polymerization initiator, as needed. The pressure-sensitive adhesive layer can be formed from a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin. Hereinafter, each component contained in the pressure-sensitive adhesive composition, which is a material for forming the pressure-sensitive adhesive layer, will be described.

[0023] (Adhesive resin) The adhesive resin is preferably a polymer that has adhesiveness by itself and has a mass average molecular weight (Mw) of 10,000 or more. From the viewpoint of improving adhesive strength, the mass average molecular weight (Mw) of the adhesive resin is more preferably 10,000 to 2,000,000, even more preferably 20,000 to 1,500,000, and even more preferably 30,000 to 1,000,000. The adhesive resin preferably has a glass transition temperature (Tg) of -60°C to -10°C, more preferably -50°C to -20°C.

[0024] Examples of adhesive resins include rubber-based resins such as acrylic resins, urethane resins, and polyisobutylene resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins. These adhesive resins may be used alone or in combination of two or more. Furthermore, when these adhesive resins are copolymers having two or more types of structural units, the form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, and a graft copolymer.

[0025] The adhesive resin may be an energy ray curable adhesive resin having a polymerizable functional group introduced into the side chain, but in this case, it is preferable to contain a photopolymerization initiator as described below. Examples of the polymerizable functional group include a (meth)acryloyl group and a vinyl group. Examples of energy rays include ultraviolet rays and electron beams. For example, when the adhesive strength between the pressure-sensitive adhesive layer and the thermoelectric conversion material chip is reduced in step (C) or step (G), which are adhesive strength reducing steps described below, it is preferable to use ultraviolet rays in one embodiment.

[0026] The content of the adhesive resin is preferably 30 to 99.99 mass%, more preferably 40 to 99.95 mass%, even more preferably 50 to 99.90 mass%, still more preferably 55 to 99.80 mass%, and even more preferably 60 to 99.50 mass%, relative to the total amount (100 mass%) of the active ingredients of the adhesive composition. In the following description of this specification, "the content of each component relative to the total amount of active ingredients in the pressure-sensitive adhesive composition" is synonymous with "the content of each component in the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition."

[0027] Here, from the viewpoint of exhibiting excellent adhesive strength, the adhesive resin preferably contains an acrylic resin. The content of the acrylic resin in the adhesive resin is preferably 30 to 100 mass%, more preferably 50 to 100 mass%, even more preferably 70 to 100 mass%, and even more preferably 85 to 100 mass%, relative to the total amount (100 mass%) of the adhesive resin contained in the adhesive composition.

[0028] (acrylic resin) Examples of acrylic resins that can be used as adhesive resins include polymers containing structural units derived from alkyl (meth)acrylates having a linear or branched alkyl group, and polymers containing structural units derived from (meth)acrylates having a cyclic structure.

[0029] The mass average molecular weight (Mw) of the acrylic resin is preferably 100,000 to 1,500,000, more preferably 200,000 to 1,300,000, and even more preferably 350,000 to 1,200,000.

[0030] The acrylic resin is more preferably an acrylic copolymer (A1) having a structural unit (a1) derived from an alkyl (meth)acrylate (a1') (hereinafter also referred to as "monomer (a1')") and a structural unit (a2) derived from a functional group-containing monomer (a2') (hereinafter also referred to as "monomer (a2')").

[0031] The number of carbon atoms in the alkyl group of the monomer (a1') is preferably 1 to 24, more preferably 1 to 12, even more preferably 2 to 10, and even more preferably 4 to 8, from the viewpoint of improving adhesive properties. The alkyl group contained in the monomer (a1') may be a linear alkyl group or a branched alkyl group.

[0032] Examples of the monomer (a1') include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate. These monomers (a1') may be used alone or in combination of two or more. The monomer (a1') is preferably at least one selected from methyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, and more preferably at least one selected from methyl (meth)acrylate and butyl (meth)acrylate.

[0033] The content of the structural unit (a1) is preferably 50 to 99.9 mass%, more preferably 60 to 99.0 mass%, even more preferably 70 to 97.0 mass%, and still more preferably 80 to 95.0 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0034] Examples of functional groups contained in the monomer (a2') include a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. That is, examples of the monomer (a2') include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers. These monomers (a2') may be used alone or in combination of two or more. Among these, as the monomer (a2'), hydroxyl group-containing monomers and carboxyl group-containing monomers are preferred, and hydroxyl group-containing monomers are more preferred.

[0035] Examples of hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol. Of these, 2-hydroxyethyl (meth)acrylate is preferred.

[0036] Examples of carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, and citraconic acid and their anhydrides; 2-(acryloyloxy)ethyl succinate; and 2-carboxyethyl (meth)acrylate.

[0037] The content of the structural unit (a2) is preferably 0.1 to 40 mass%, more preferably 0.5 to 35 mass%, even more preferably 1.0 to 30 mass%, and even more preferably 3.0 to 25 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0038] The acrylic copolymer (A1) may further include a structural unit (a3) ​​derived from a monomer (a3') other than the monomers (a1') and (a2'). In the acrylic copolymer (A1), the content of the structural units (a1) and (a2) is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, even more preferably 90 to 100 mass%, and still more preferably 95 to 100 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0039] Examples of the monomer (a3') include olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene, and chloroprene; (meth)acrylates having a cyclic structure such as cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and imide (meth)acrylate; styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth)acrylamide, (meth)acrylonitrile, (meth)acryloylmorpholine, and N-vinylpyrrolidone.

[0040] The acrylic copolymer (A1) may also be an energy ray-curable acrylic copolymer having a polymerizable functional group introduced into the side chain. Examples of the polymerizable functional group include a (meth)acryloyl group and a vinyl group. The energy rays include ultraviolet rays and electron beams, with ultraviolet rays being preferred. The polymerizable functional group can be introduced by reacting an acrylic copolymer having the above-mentioned structural units (a1) and (a2) with a compound having a polymerizable functional group and a substituent capable of bonding to the functional group possessed by the structural unit (a2) of the acrylic copolymer. Examples of the compound include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and glycidyl (meth)acrylate.

[0041] (Crosslinking agent) The pressure-sensitive adhesive composition preferably further contains a crosslinking agent. The crosslinking agent reacts with a pressure-sensitive adhesive resin having a functional group, such as the above-mentioned acrylic copolymer (A1), and crosslinks the pressure-sensitive adhesive resins together using the functional group as the crosslinking starting point.

[0042] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, and a metal chelate-based crosslinking agent. These crosslinking agents may be used alone or in combination of two or more. Among these crosslinking agents, isocyanate-based crosslinking agents are preferred from the viewpoints of increasing cohesive strength and improving adhesive strength, and of easy availability.

[0043] The content of the crosslinking agent is adjusted appropriately depending on the number of functional groups possessed by the adhesive resin, but is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 5 parts by mass per 100 parts by mass of the adhesive resin having functional groups.

[0044] (tackifier) In the present embodiment, the pressure-sensitive adhesive composition may further contain a tackifier from the viewpoint of further improving adhesive strength. In this specification, the term "tackifier" refers to a component that auxiliary improves the adhesive strength of the above-mentioned adhesive resin, and refers to an oligomer with a mass average molecular weight (Mw) of less than 10,000, and is distinguished from the above-mentioned adhesive resin. The mass average molecular weight (Mw) of the tackifier is preferably from 400 to less than 10,000, more preferably from 500 to 8,000, and even more preferably from 800 to 5,000.

[0045] Examples of tackifiers include rosin resins, terpene resins, styrene resins, C5 petroleum resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine, and 1,3-pentadiene produced by thermal decomposition of petroleum naphtha, C9 petroleum resins obtained by copolymerizing C9 fractions such as indene and vinyltoluene produced by thermal decomposition of petroleum naphtha, and hydrogenated resins obtained by hydrogenating these.

[0046] The softening point of the tackifier is preferably 60 to 170°C, more preferably 65 to 160°C, and even more preferably 70 to 150°C. In this specification, the "softening point" of a tackifier means a value measured in accordance with JIS K 2531. The tackifier may be used alone or in combination of two or more types having different softening points, structures, etc. When two or more types of tackifiers are used, it is preferable that the weighted average of the softening points of the tackifiers falls within the above range.

[0047] The content of the tackifier is preferably 0.01 to 65 mass%, more preferably 0.05 to 55 mass%, even more preferably 0.1 to 50 mass%, still more preferably 0.5 to 45 mass%, and even more preferably 1.0 to 40 mass%, relative to the total amount (100 mass%) of the active ingredients in the pressure-sensitive adhesive composition.

[0048] (Photopolymerization initiator) In the present embodiment, when the pressure-sensitive adhesive composition contains an energy ray-curable pressure-sensitive adhesive resin as the pressure-sensitive adhesive resin, it is preferable that the pressure-sensitive adhesive composition further contains a photopolymerization initiator. By including a photopolymerization initiator, the curing reaction can be sufficiently promoted even by irradiation with energy rays having a relatively low energy. Examples of photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, and 8-chloroanthraquinone. These photopolymerization initiators may be used alone or in combination of two or more.

[0049] The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 2 parts by mass, relative to 100 parts by mass of the energy ray-curable adhesive resin.

[0050] (coloring agent) In the adhesive strength reducing step (C) or (G) described below, when laser light is used, the adhesive layer preferably contains a colorant that absorbs laser light of a specific wavelength and generates heat. The colorant may be, for example, one or more selected from pigments and dyes. The pigment may be an organic pigment or an inorganic pigment. Examples of dyes include basic dyes, acid dyes, disperse dyes, and direct dyes. Examples of black pigments include carbon black, copper oxide, iron oxide, manganese dioxide, aniline black, and activated carbon. Examples of yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake. Examples of orange pigments include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, induthrene brilliant orange RK, benzidine orange G, and induthrene brilliant orange GKM. Examples of red pigments include red iron oxide, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, lithol red, pyrozolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, and brilliant carmine 3B. Examples of purple pigments include manganese violet, fast violet B, and methyl violet lake. Examples of blue pigments include Prussian blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, and indanthrene blue BC. Examples of green pigments include chrome green, chromium oxide, pigment green B, malachite green lake, and final yellow green G. Examples of dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue. The content of the colorant can be adjusted as appropriate by changing the wavelength, output, irradiation time, etc. of the laser light, but is usually preferably 0.01 to 10 mass %, more preferably 0.05 to 7 mass %, and even more preferably 0.1 to 5 mass %, relative to the total amount of the pressure-sensitive adhesive composition.

[0051] (metal filler) When laser light is used in the adhesive strength reducing step (C) or (G) described below, the pressure-sensitive adhesive layer may contain a metal filler or the like that absorbs laser light of a specific wavelength and generates heat. The metal filler is not particularly limited, but examples thereof include metal fillers made of copper, silver, gold, zinc, nickel, or palladium. The content of the metal filler can be adjusted as appropriate by changing the wavelength, output, irradiation time, etc. of the laser light, but is usually preferably 0.01 to 10 mass%, more preferably 0.05 to 5 mass%, and even more preferably 0.1 to 3 mass%, relative to the total amount of the pressure-sensitive adhesive composition. The colorant and the metal filler may be used in combination.

[0052] <Thermoelectric conversion material layer> The thermoelectric conversion material layer used in the present invention (hereinafter sometimes referred to as a "thin film of thermoelectric conversion material layer" or a "chip of thermoelectric conversion material") is not particularly limited, and may be made of a thermoelectric semiconductor material or a thin film made of a thermoelectric semiconductor composition. From the viewpoint of flexibility and thinness, it is preferable that the thermoelectric element is made of a thin film made of a thermoelectric semiconductor composition containing a thermoelectric semiconductor material (hereinafter sometimes referred to as "thermoelectric semiconductor particles"), a resin, an ionic liquid, and / or an inorganic ionic compound.

[0053] (Thermoelectric semiconductor materials) The thermoelectric semiconductor material used in the thermoelectric conversion material layer is preferably pulverized to a predetermined size using, for example, a fine grinding device and used as thermoelectric semiconductor particles (hereinafter, the thermoelectric semiconductor material may be referred to as "thermoelectric semiconductor particles"). The particle size of the thermoelectric semiconductor particles is preferably 10 nm to 100 μm, more preferably 20 nm to 50 μm, and even more preferably 30 nm to 30 μm. The average particle size of the thermoelectric semiconductor particles was obtained by measurement using a laser diffraction particle size analyzer (Malvern, Mastersizer 3000) and was taken as the median value of the particle size distribution.

[0054] In the thermoelectric conversion material layer used in the present invention, the thermoelectric semiconductor materials constituting the P-type thermoelectric conversion material layer and the N-type conversion material layer are not particularly limited as long as they can generate a thermoelectromotive force by applying a temperature difference. For example, bismuth-tellurium-based thermoelectric semiconductor materials such as P-type bismuth telluride and N-type bismuth telluride; telluride-based thermoelectric semiconductor materials such as GeTe and PbTe; antimony-tellurium-based thermoelectric semiconductor materials; zinc-antimony-based thermoelectric semiconductor materials such as ZnSb and Zn3Sb 2、 Zn4Sb3; silicon-germanium-based thermoelectric semiconductor materials such as SiGe; bismuth selenide-based thermoelectric semiconductor materials such as Bi2Se3; β-FeSi2, CrSi2, MnSi 1.73 , Mg2Si and other silicide-based thermoelectric semiconductor materials; oxide-based thermoelectric semiconductor materials; Heusler materials such as FeVAl, FeVAlSi, FeVTiAl, and sulfide-based thermoelectric semiconductor materials such as TiS2 are used.

[0055] Among these, the thermoelectric semiconductor material used in the present invention is preferably a bismuth-tellurium-based thermoelectric semiconductor material such as P-type bismuth telluride or N-type bismuth telluride. The P-type bismuth telluride has holes as carriers and a positive value of the Seebeck coefficient. For example, Bi X Te3Sb 2-X represented by is preferably used. In this case, X is preferably 0 < X ≤ 0.8, more preferably 0.4 ≤ X ≤ 0.6. When X is greater than 0 and less than or equal to 0.8, the Seebeck coefficient and electrical conductivity increase, and the characteristics as a P-type thermoelectric conversion material are maintained, which is preferable. Further, the N-type bismuth telluride has electrons as carriers and a negative value of the Seebeck coefficient. For example, Bi2Te 3-Y Se Y represented by is preferably used. In this case, Y is preferably 0 ≤ Y ≤ 3 (when Y = 0: Bi2Te3), more preferably 0.1 < Y ≤ 2.7. When Y is 0 or more and 3 or less, the Seebeck coefficient and electrical conductivity increase, and the characteristics as an N-type thermoelectric conversion material are maintained, which is preferable.

[0056] The content of the thermoelectric semiconductor particles in the thermoelectric semiconductor composition is preferably 30 to 99% by mass, more preferably 50 to 96% by mass, and even more preferably 70 to 95% by mass. When the content of the thermoelectric semiconductor particles is within the above range, the Seebeck coefficient (absolute value of the Peltier coefficient) is large, and a decrease in electrical conductivity is suppressed, with only a decrease in thermal conductivity, so that a film exhibiting high thermoelectric performance and having sufficient film strength and flexibility is obtained, which is preferable.

[0057] Furthermore, the thermoelectric semiconductor particles are preferably subjected to an annealing treatment (hereinafter sometimes referred to as "annealing treatment A"). By performing annealing treatment A, the crystallinity of the thermoelectric semiconductor particles is improved, and furthermore, the surface oxide film of the thermoelectric semiconductor particles is removed, thereby increasing the Seebeck coefficient (absolute value of the Peltier coefficient) of the thermoelectric conversion material and further improving the thermoelectric figure of merit.

[0058] (resin) The resin used in the present invention has the effect of physically bonding the thermoelectric semiconductor material (thermoelectric semiconductor particles) together, which can increase the flexibility of the thermoelectric conversion module and also makes it easier to form a thin film by coating or the like. The resin is preferably a heat-resistant resin or a binder resin.

[0059] The heat-resistant resin maintains its physical properties such as mechanical strength and thermal conductivity without being impaired when the thin film made of the thermoelectric semiconductor composition is annealed or otherwise treated to cause crystal growth of thermoelectric semiconductor particles. The heat-resistant resin is preferably a polyamide resin, a polyamide-imide resin, a polyimide resin, or an epoxy resin, because it has higher heat resistance and does not adversely affect the crystal growth of the thermoelectric semiconductor particles in the thin film, and more preferably a polyamide resin, a polyamide-imide resin, or a polyimide resin, because it has excellent flexibility.

[0060] The heat-resistant resin preferably has a decomposition temperature of 300° C. or higher. If the decomposition temperature is within the above range, the resin will not lose its function as a binder and will be able to maintain flexibility even when a thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

[0061] Furthermore, the heat-resistant resin preferably has a mass loss rate of 10% or less, more preferably 5% or less, and even more preferably 1% or less at 300°C as measured by thermogravimetry (TG). If the mass loss rate is within the above range, as will be described later, even when a thin film made of the thermoelectric semiconductor composition is annealed, the resin does not lose its function as a binder and the flexibility of the thermoelectric conversion material chip can be maintained.

[0062] The content of the heat-resistant resin in the thermoelectric semiconductor composition is 0.1 to 40% by mass, preferably 0.5 to 20% by mass, more preferably 1 to 20% by mass, and even more preferably 2 to 15% by mass. When the content of the heat-resistant resin is within the above range, it functions as a binder for the thermoelectric semiconductor material, making it easier to form a thin film, and a film that achieves both high thermoelectric performance and film strength is obtained, and a resin portion is present on the outer surface of the chip of the thermoelectric conversion material.

[0063] The binder resin also facilitates the separation of the thermoelectric conversion material from the substrate, such as glass, alumina, or silicon, used in the production of chips after the firing (annealing) treatment (corresponding to "annealing treatment B" described below, and the same applies below).

[0064] The binder resin refers to a resin that decomposes at 90% by mass or more at a baking (annealing) temperature or higher, more preferably a resin that decomposes at 95% by mass or more, and particularly preferably a resin that decomposes at 99% by mass or more. Furthermore, a resin that maintains various physical properties such as mechanical strength and thermal conductivity without being impaired when a coating film (thin film) made of a thermoelectric semiconductor composition is subjected to a baking (annealing) treatment or the like to cause crystal growth of thermoelectric semiconductor particles is more preferred. When a resin that decomposes at 90% by mass or more at temperatures equal to or higher than the firing (annealing) temperature, i.e., a resin that decomposes at a temperature lower than the heat-resistant resin described above, is used as the binder resin, the binder resin is decomposed by firing, and therefore the content of the binder resin, which serves as an insulating component in the fired body, is reduced, and crystal growth of the thermoelectric semiconductor particles in the thermoelectric semiconductor composition is promoted, thereby reducing voids in the thermoelectric conversion material layer and improving the filling rate. Whether or not a resin decomposes to a predetermined extent (e.g., 90% by mass) at or above the baking (annealing) temperature is determined by measuring the mass loss rate (the value obtained by dividing the mass after decomposition by the mass before decomposition) at the baking (annealing) temperature using thermogravimetry (TG).

[0065] Thermoplastic resins and curable resins can be used as such binder resins. Examples of thermoplastic resins include polyolefin resins such as polyethylene, polypropylene, polyisobutylene, and polymethylpentene; polycarbonate; thermoplastic polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyvinyl polymers such as polystyrene, acrylonitrile-styrene copolymer, polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl chloride, polyvinylpyridine, polyvinyl alcohol, and polyvinylpyrrolidone; polyurethane; and cellulose derivatives such as ethyl cellulose. Examples of curable resins include thermosetting resins and photocurable resins. Examples of thermosetting resins include epoxy resins and phenolic resins. Examples of photocurable resins include photocurable acrylic resins, photocurable urethane resins, and photocurable epoxy resins. These resins may be used alone or in combination. Among these, from the viewpoint of the electrical resistivity of the thermoelectric conversion material in the thermoelectric conversion material layer, thermoplastic resins are preferred, polycarbonate and cellulose derivatives such as ethyl cellulose are more preferred, and polycarbonate is particularly preferred.

[0066] The binder resin is appropriately selected depending on the temperature of the annealing treatment of the thermoelectric semiconductor material in the annealing treatment step. From the viewpoint of the electrical resistivity of the thermoelectric conversion material in the thermoelectric conversion material layer, it is preferable to perform the annealing treatment at a temperature equal to or higher than the final decomposition temperature of the binder resin. In this specification, the term "final decomposition temperature" refers to the temperature at which the mass reduction rate at the firing (annealing) temperature determined by thermogravimetry (TG) is 100% (the mass after decomposition is 0% of the mass before decomposition).

[0067] The final decomposition temperature of the binder resin is usually 150 to 600° C., preferably 200 to 560° C., more preferably 220 to 460° C., and particularly preferably 240 to 360° C. If a binder resin with a final decomposition temperature within this range is used, it functions as a binder for the thermoelectric semiconductor material, making it easier to form a thin film during printing.

[0068] The content of the binder resin in the thermoelectric semiconductor composition is 0.1 to 40 mass%, preferably 0.5 to 20 mass%, more preferably 0.5 to 10 mass%, and particularly preferably 0.5 to 5 mass%. When the content of the binder resin is within the above range, the electrical resistivity of the thermoelectric conversion material in the thermoelectric conversion material layer can be reduced.

[0069] The content of the binder resin in the thermoelectric conversion material is preferably 0 to 10 mass %, more preferably 0 to 5 mass %, and particularly preferably 0 to 1 mass %. If the content of the binder resin in the thermoelectric conversion material is within the above range, the electrical resistivity of the thermoelectric conversion material in the thermoelectric conversion material layer can be reduced.

[0070] (ionic liquid) The ionic liquid that can be contained in the thermoelectric semiconductor composition is a molten salt formed by combining a cation and an anion, and refers to a salt that can exist in liquid form at any temperature range from -50°C to less than 400°C. In other words, an ionic liquid is an ionic compound with a melting point in the range of -50°C to less than 400°C. The melting point of the ionic liquid is preferably -25°C to 200°C, more preferably 0°C to 150°C. Ionic liquids have characteristics such as extremely low vapor pressure and nonvolatility, excellent thermal and electrochemical stability, low viscosity, and high ionic conductivity. Therefore, as a conductive additive, they can effectively suppress a decrease in electrical conductivity between thermoelectric semiconductor materials. Furthermore, ionic liquids exhibit high polarity due to their aprotic ionic structure and excellent compatibility with heat-resistant resins, thereby enabling the electrical conductivity of thermoelectric conversion materials to be uniform.

[0071] The ionic liquid may be a known or commercially available one. For example, a nitrogen-containing cyclic cationic compound such as pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, or imidazolium, or a derivative thereof; a tetraalkylammonium-based amine-based cation and a derivative thereof; a phosphine-based cation such as phosphonium, trialkylsulfonium, or tetraalkylphosphonium, or a derivative thereof; a lithium cation and a derivative thereof; or a mixture of a cation component and a Cl cation. - , Br - , I - , AlCl4 - , Al2Cl7 - , BF4 - , PF6 - , ClO4 - , NO3 - , CH3COO - , CF3COO - , CH3SO3 - , CF3SO3 - , (FSO2)2N - , (CF3SO2)2N - , (CF3SO2)3C - , AsF6 - , SbF6 - , NbF6 - , TaF6- , F(HF) n - , (CN)2N - , C4F9SO3 - , (C2F5SO2)2N - , C3F7COO - , (CF3SO2)(CF3CO)N - and an anion component such as the above.

[0072] Among the above-mentioned ionic liquids, from the viewpoints of high-temperature stability, compatibility with thermoelectric semiconductor materials and resins, and suppression of a decrease in the electrical conductivity of the gaps between thermoelectric semiconductor materials, it is preferred that the cationic component of the ionic liquid contains at least one selected from pyridinium cations and derivatives thereof, and imidazolium cations and derivatives thereof.

[0073] As the ionic liquid in which the cationic component contains a pyridinium cation or a derivative thereof, 1-butyl-4-methylpyridinium bromide, 1-butylpyridinium bromide, and 1-butyl-4-methylpyridinium hexafluorophosphate are preferred.

[0074] Furthermore, as the ionic liquid in which the cationic component contains an imidazolium cation and a derivative thereof, [1-butyl-3-(2-hydroxyethyl)imidazolium bromide] and [1-butyl-3-(2-hydroxyethyl)imidazolium tetrafluoroborate] are preferred.

[0075] The ionic liquid preferably has a decomposition temperature of 300° C. or higher. If the decomposition temperature is within the above range, the ionic liquid can maintain its effect as a conductive additive even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0076] The content of the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50 mass%, more preferably 0.5 to 30 mass%, and even more preferably 1.0 to 20 mass%. If the content of the ionic liquid is within the above range, a decrease in electrical conductivity is effectively suppressed, and a film with high thermoelectric performance is obtained.

[0077] (inorganic ionic compounds) The inorganic ionic compound that can be contained in the thermoelectric semiconductor composition is a compound composed of at least a cation and an anion. The inorganic ionic compound exists in a solid state over a wide temperature range from 400 to 900°C and has characteristics such as high ionic conductivity, so that it can act as a conductive additive to suppress a decrease in electrical conductivity between thermoelectric semiconductor materials.

[0078] The content of the inorganic ionic compound in the thermoelectric semiconductor composition is preferably 0.01 to 50 mass%, more preferably 0.5 to 30 mass%, and even more preferably 1.0 to 10 mass%. If the content of the inorganic ionic compound is within the above range, a decrease in electrical conductivity can be effectively suppressed, and as a result, a film with improved thermoelectric performance can be obtained. When an inorganic ionic compound and an ionic liquid are used in combination, the total content of the inorganic ionic compound and the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50 mass%, more preferably 0.5 to 30 mass%, and even more preferably 1.0 to 10 mass%.

[0079] The thermoelectric conversion material layer is formed by adhering it to a fixing layer on a support. In one embodiment, for example, a thermoelectric conversion material layer prepared in advance on a peelable substrate is used. From the viewpoint of thermoelectric performance, when annealing treatment B described later is performed, it is preferable to perform annealing treatment B before the adhering. The thermoelectric conversion material layer made of the thermoelectric semiconductor composition used in the present invention can be formed, for example, by applying the thermoelectric semiconductor composition to a known substrate such as glass, silicon, etc., and then drying the composition. By forming the thermoelectric conversion material layer in this manner, a large number of thermoelectric conversion material layers can be obtained easily and at low cost. Examples of a method for applying the thermoelectric semiconductor composition to obtain a thermoelectric conversion material layer include known methods such as screen printing, flexographic printing, gravure printing, spin coating, dip coating, die coating, spray coating, bar coating, and doctor blade coating, and are not particularly limited. The resulting coating film is then dried to form a thermoelectric conversion material layer.

[0080] The thickness of the thermoelectric conversion material layer is not particularly limited, but is preferably 100 nm to 1000 μm, more preferably 300 nm to 600 μm, and even more preferably 5 to 400 μm, from the viewpoint of thermoelectric performance and film strength.

[0081] The P-type thermoelectric conversion material layer and the N-type thermoelectric conversion material layer as thin films made of the thermoelectric semiconductor composition are preferably further annealed (hereinafter, sometimes referred to as "annealing treatment B"). By performing annealing treatment B, the thermoelectric performance can be stabilized and the thermoelectric semiconductor particles in the thin film can undergo crystal growth, thereby further improving the thermoelectric performance. Annealing treatment B is not particularly limited, but is usually performed in an inert gas atmosphere such as nitrogen or argon, in a reducing gas atmosphere, or under vacuum conditions with a controlled gas flow rate, and is performed at 100 to 500°C for several minutes to several tens of hours, depending on the heat resistance temperature of the thermoelectric semiconductor composition, substrate, etc. used.

[0082] Thermoelectric conversion material chip formation process The method for arranging chips of thermoelectric conversion material of the present invention includes (B) a step of forming chips of P-type thermoelectric conversion material, and (F) a step of forming chips of N-type thermoelectric conversion material. The thermoelectric conversion material chip formation process is a process of singulating a thermoelectric conversion material layer to obtain thermoelectric conversion material chips, for example, in Figure 1(b), it is a process of singulating a P-type thermoelectric conversion material layer 3p to obtain P-type thermoelectric conversion material chips 3pt [Step (B)]. Similarly, in Figure 1(f), it is a process of singulating an N-type thermoelectric conversion material layer 3n to obtain N-type thermoelectric conversion material chips 3nt [Step (F)].

[0083] The method for dividing the thermoelectric conversion material layer into individual pieces is not particularly limited, and any known method can be used, for example, a dicing method. The dicing method is not particularly limited, but known methods such as blade dicing and laser dicing can be used. For example, the dicing is performed by providing cuts that penetrate the thermoelectric conversion material layer.

[0084] ·Adhesion strength reduction process The method for arranging chips of thermoelectric conversion material of the present invention includes an adhesive strength reducing step (C) for chips of P-type thermoelectric conversion material, and an adhesive strength reducing step (G) for chips of N-type thermoelectric conversion material. The adhesive strength reducing step is a step of reducing the adhesive strength between the fixing layer and the thermoelectric conversion material chips, for example, in Fig. 1(c), it is a step of reducing the adhesive strength of the fixing layer 2 in the region where some of the P-type thermoelectric conversion material chips 3pt are attached [Step (C)]. Similarly, in Fig. 1(g), it is a step of reducing the adhesive strength of the fixing layer 2 in the region where some of the N-type thermoelectric conversion material chips 3nt are attached [Step (G)].

[0085] In one embodiment, the adhesive strength reducing step is preferably performed by making the fixing layer a fixing layer capable of absorbing laser light, and by irradiating the laser light to at least a portion of the fixing layer in each region where the portion of the P-type thermoelectric conversion material chips and the portion of the N-type thermoelectric conversion material chips are adhered, in this order.

[0086] Figure 2 is a cross-sectional schematic diagram showing one embodiment of the adhesive strength reduction process in the present invention, and schematically shows an embodiment in which the adhesive strength between some of the P-type thermoelectric conversion material chips 3pt and the fixing layer 2 among multiple P-type thermoelectric conversion material chips 3pt attached to the fixing layer 2 on the first support 1a is reduced. In step (C) or (G), when the adhesive strength between the fixing layer and the thermoelectric conversion material chips is reduced by irradiation with laser light, for example, a laser irradiation device 4 is used to irradiate at least a portion of the fixing layer 2 in the region where some of the P-type thermoelectric conversion material chips 3pt are attached from the surface of the fixing layer 2 opposite to the surface to which the P-type thermoelectric conversion material chips 3pt are attached. This ablates part of the fixing layer 2, generating sublimation gas 6, and reduces the contact area between some of the P-type thermoelectric conversion material chips 3pt and the fixing layer 2 around the area irradiated with the laser light 4. Then, by further scanning the laser light 5 in the in-plane direction of the fixing layer 2 to expand the area irradiated to the fixing layer 2, the fixing layer 2 is ablated over a wider area, generating sublimation gas, and further reducing the contact area between some of the P-type thermoelectric conversion material chips 3pt and the fixing layer 2, thereby further reducing the adhesive strength between some of the P-type thermoelectric conversion material chips 3pt and the fixing layer 2. Even if the sublimation gas 6 leaks around some of the P-type thermoelectric conversion material chips 3pt, the leaked sublimation gas 6 is released from the gaps 7 between the P-type thermoelectric conversion material chips 3pt. Therefore, it is possible to prevent a decrease in adhesive strength for the P-type thermoelectric conversion material chips 3pt where peeling around some of the P-type thermoelectric conversion material chips 3pt is not desired. Another embodiment of the laser light irradiation means is preferably, from the viewpoint of productivity, to use a multi-array laser in accordance with the arrangement and number of some of the thermoelectric conversion material chips and irradiate them all at once.

[0087] In another embodiment, in step (C) or step (G), the adhesive strength between the fixing layer and the thermoelectric conversion material chips is preferably reduced by ultraviolet irradiation. In this case, for example, all of the thermoelectric conversion material chips for which adhesive strength reduction is not desired are masked together with the support from the surface of the fixing layer opposite to the surface where the thermoelectric conversion material chips are attached, and ultraviolet light is irradiated from the masked surface side using an ultraviolet irradiation device to each of the fixing layer regions where some of the thermoelectric conversion material chips are attached, thereby reducing the adhesive strength between the fixing layer and all of some of the thermoelectric conversion material chips, and all of some of the thermoelectric conversion material chips among the plurality of thermoelectric conversion material chips can be selectively and easily peeled off together with the support. There are no particular restrictions on the masking material as long as it is a material that does not transmit ultraviolet light and does not increase in temperature much, and metal plates with high thermal conductivity such as aluminum can be used.

[0088] Furthermore, in another embodiment, it is preferable that the support is the above-mentioned thermally expandable substrate, and that one or both of the steps (C) and (G) are carried out by selectively heating at least a portion of the thermally expandable substrate in the same region as the fixing layer in each region to which a corresponding portion of the P-type thermoelectric conversion material chips and a corresponding portion of the N-type thermoelectric conversion material chips are attached. By heating a portion of the heat-expandable substrate to a temperature above the temperature at which the heat-expandable particles expand, the heat-expandable substrate deforms in accordance with the volumetric expansion of the heat-expandable particles at the temperature at which the heat-expandable particles expand, forming irregularities on the surface of the adhesive layer, which serves as the fixing layer, on the side of the thermoelectric conversion material chip, making it possible to easily and selectively peel off some of the thermoelectric conversion material chips from among the multiple thermoelectric conversion material chips.

[0089] The heating means for the thermally expandable substrate as a support is not particularly limited as long as it can selectively heat the substrate to a temperature equal to or higher than the temperature at which the thermally expandable particles in the thermally expandable substrate, and for example, heating by electromagnetic waves such as near infrared rays, mid infrared rays, far infrared rays, etc. can be appropriately used. The heating method may be either a direct heating method or an indirect heating method.

[0090] Furthermore, in another embodiment, it is preferable that one or both of the steps (C) and (G) are carried out by selectively heating at least a portion of the thermally expandable particles in the fixing layer in each region where a corresponding portion of the P-type thermoelectric conversion material chips and a corresponding portion of the N-type thermoelectric conversion material chips are attached. From the viewpoint of more easily peeling off the chips of the corresponding portion of P-type thermoelectric conversion material and the chips of the corresponding portion of N-type thermoelectric conversion material, a fixing layer (adhesive layer) containing thermally expandable particles and a thermally expandable substrate as a support may be used in combination in one or both of the steps (C) and (G).

[0091] Thermoelectric conversion material chip transfer process The method for arranging chips of thermoelectric conversion material of the present invention includes (D) a step of transferring chips of P-type thermoelectric conversion material, and (H) a step of transferring chips of N-type thermoelectric conversion material. The thermoelectric conversion material chip transfer process is a process in which only some of the thermoelectric conversion material chips with reduced adhesive strength are selectively transferred and attached to the fixing layer on another support. For example, in Figure 1(d), only some of the P-type thermoelectric conversion material chips 3pt are selectively peeled from the fixing layer 2 on the first support 1a and transferred and attached to the fixing layer 2 on the second support 1b [Step (D)]. Similarly, in Figure 1(h), only some of the N-type thermoelectric conversion material chips 3nt are selectively peeled from the fixing layer 2 on the third support 1c and transferred and attached to the fixing layer 2 on the fourth support 1d [Step (H)]. The method for transferring and adhering the thermoelectric conversion material chip from the fixing layer with reduced adhesive strength onto the fixing layer on another support is not particularly limited, and can be carried out by a known method.

[0092] Thermoelectric conversion material chip bonding process The method for arranging chips of thermoelectric conversion material of the present invention includes (I) a step of bonding chips of thermoelectric conversion material together and (J) a step of bonding chips of thermoelectric conversion material together. The thermoelectric conversion material chip bonding step is a step of bonding together the surfaces of the thermoelectric conversion material chips on the two supports, with the surfaces of the chips facing each other, so that the spaced P-type thermoelectric conversion material chips (or N-type thermoelectric conversion material chips) attached to the fixing layer on the support obtained in the thermoelectric conversion material chip transfer step and the spaced N-type thermoelectric conversion material chips (or P-type thermoelectric conversion material chips) on the fixing layer on another support are arranged in a predetermined manner. For example, in Figure 1(i), this is a step of bonding together the spaced N-type thermoelectric conversion material chips 3nt transferred to the fixing layer 2 on the fourth support 1d obtained in the transfer step and the spaced P-type thermoelectric conversion material chips 3pt on the fixing layer 2 on the first support 1a, so that the N-type thermoelectric conversion material chips 3nt and the P-type thermoelectric conversion material chips 3pt are arranged alternately [Step (I)]. Similarly, for example, in Figure 1(j), there is a step (J) in which spaced apart chips 3pt of P-type thermoelectric conversion material transferred to the fixing layer 2 on the second support 1b obtained in the transfer step are bonded to spaced apart chips 3nt of N-type thermoelectric conversion material on the fixing layer 2 on the third support 1c, and the chips 3pt of P-type thermoelectric conversion material and the chips 3nt of N-type thermoelectric conversion material are arranged alternately. There are no particular limitations on the method for bonding the spaced P-type thermoelectric conversion material chips (or N-type thermoelectric conversion material chips) attached to the fixing layer on the support obtained in the thermoelectric conversion material chip transfer process and the spaced N-type thermoelectric conversion material chips (or P-type thermoelectric conversion material chips) attached to the fixing layer on another support in a predetermined arrangement, and any known method can be used. For example, when bonding spaced apart chips 3nt of N-type thermoelectric conversion material transferred to the fixing layer 2 on the fourth support 1d obtained in the transfer process with spaced apart chips 3pt of P-type thermoelectric conversion material on the fixing layer 2 on the first support 1a, alignment marks are provided in advance on the first support and the second support, and alignment is performed using a microscope or the like, and they are bonded together using a known method in order to accurately position the spaced apart chips 3pt of P-type thermoelectric conversion material on the fixing layer 2 on the first support 1a at a predetermined position between the spaced apart chips 3nt of N-type thermoelectric conversion material transferred to the fixing layer 2 on the fourth support 1d.

[0093] The method for arranging thermoelectric conversion material chips of the present invention further includes a step of peeling one of the supports having a fixing layer from the thermoelectric conversion material chips. For example, in FIG. 1(i'), this is a step of peeling the fixing layer on the first support 1a from the surface of N-type thermoelectric conversion material chips 3nt and P-type thermoelectric conversion material chips 3pt, which are alternately arranged on the fixing layer 2 on the fourth support 1d. Similarly, in FIG. 1(j'), this is a step of peeling the fixing layer on the third support 1c from the surface of P-type thermoelectric conversion material chips 3pt and N-type thermoelectric conversion material chips 3nt, which are alternately arranged on the fixing layer 2 on the second support 1b. As a method for peeling off one of the supports having the fixing layer, the adhesive strength of all of the fixing layers attached to the region of the thermoelectric conversion material chip where the adhesive strength has not been reduced [for example, in Figure 1(i'), it corresponds to 3pt of the P-type thermoelectric conversion material chip] may be reduced in the same manner as in step (C) or step (G), and then the fixing layers may be peeled off by a known method. In addition, from the viewpoint of facilitating the peeling, it is preferable to make the adhesive strength of the fixing layer on one support to be peeled (e.g., the adhesive strength of the pressure-sensitive adhesive layer) lower than the adhesive strength of the fixing layer on the opposing support that is not to be peeled (e.g., the adhesive strength of the pressure-sensitive adhesive layer).

[0094] [Method of manufacturing a chip array of thermoelectric conversion materials] The method for producing a thermoelectric conversion material chip array of the present invention includes the steps of carrying out the method for arranging thermoelectric conversion material chips of the present invention, which includes steps (A) to (J), or the arranging method of one aspect of the present invention. In particular, the method for manufacturing a thermoelectric conversion material chip array of the present invention includes a step of carrying out a method for arranging thermoelectric conversion material chips of one embodiment of the present invention, which includes steps (A) to (J) in this order, and thereby makes it possible to manufacture a thermoelectric conversion material chip array in which chips of P-type and N-type thermoelectric conversion material are efficiently arranged alternately on a support body from P-type and N-type thermoelectric conversion material layers.

[0095] [Method of manufacturing thermoelectric conversion modules] The method for producing a thermoelectric conversion module of the present invention includes a step of carrying out the method for arranging chips of thermoelectric conversion material of the present invention or the arranging method of one aspect of the present invention, which includes steps (A) to (J). Therefore, all of the plurality of chips of P-type and N-type thermoelectric conversion materials arranged alternately on the support body can be subjected to the assembly process of the thermoelectric conversion module. Specifically, it becomes possible to subject all of the multiple P-type and N-type thermoelectric conversion material chips arranged alternately on the support body to the thermoelectric conversion module assembly process, which contributes to improving the yield and productivity of thermoelectric conversion modules.

[0096] According to the method for arranging chips of thermoelectric conversion material of the present invention, chips of P-type conversion material and chips of N-type thermoelectric conversion material can be arranged alternately and efficiently on a support body at once. Therefore, by subjecting this to the assembly process of a thermoelectric conversion module, productivity of the thermoelectric conversion module can be improved. [Industrial Applicability]

[0097] In the method for manufacturing thermoelectric conversion material chips, which includes a step of carrying out the method for arranging thermoelectric conversion material chips of the present invention, it is possible to subject all of the multiple P-type and N-type thermoelectric conversion material chips arranged alternately on a support body to the thermoelectric conversion module assembly process, which leads to improved productivity, including an increase in the yield of thermoelectric conversion modules, and is expected to enable the mass production of inexpensive thermoelectric conversion modules. [Explanation of symbols]

[0098] 1a: First support 1b: Second support 1c: Third support 1d: Fourth support 2: Fixed layer 3p: P-type thermoelectric conversion material layer 3n: N-type thermoelectric conversion material layer 3pt: P-type thermoelectric conversion material chip 3nt: N-type thermoelectric conversion material chip 4: Laser irradiation device 5: Laser light 6: Sublimation gas 7: Gap

Claims

1. A method for arranging chips of thermoelectric conversion material, the chips of thermoelectric conversion material including chips of P-type thermoelectric conversion material and chips of N-type thermoelectric conversion material, (A) a step of attaching a P-type thermoelectric conversion material layer to a fixing layer on a first support; (B) dividing the P-type thermoelectric conversion material layer attached to the fixing layer on the first support into P-type thermoelectric conversion material chips to obtain a plurality of P-type thermoelectric conversion material chips; (C) reducing the adhesive strength between some of the P-type thermoelectric conversion material chips and the fixing layer; (D) peeling off the part of the P-type thermoelectric conversion material chips whose adhesive strength to the fixing layer has decreased from the fixing layer on the first support, and transferring and attaching the surface of the part of the P-type thermoelectric semiconductor chips opposite to the attachment surface to the fixing layer on a second support; (E) a step of attaching the N-type thermoelectric conversion material layer to a fixing layer on a third support; (F) a step of singulating the N-type thermoelectric conversion material layer attached to the fixing layer on the third support into N-type thermoelectric conversion material chips to obtain a plurality of N-type thermoelectric conversion material chips; (G) reducing the adhesive strength between some of the N-type thermoelectric conversion material chips and the fixing layer; (H) peeling off the chips of the N-type thermoelectric conversion material, the adhesive strength of which has decreased with respect to the fixing layer, from the fixing layer on the third support, and transferring and attaching the surface of the chips of the N-type thermoelectric conversion material opposite to the attachment surface to the fixing layer on a fourth support; (I) a step of attaching a surface opposite to the attachment surface of the chips of the P-type thermoelectric conversion material, whose adhesive strength with the fixing layer has been maintained in the step (D), to the fixing layer between the chips of the part of the N-type thermoelectric conversion material attached to the fixing layer on the fourth support obtained in the step (H); (J) a step of attaching a surface opposite to the attachment surface of the chips of N-type thermoelectric conversion material, whose adhesive strength with the fixing layer has been maintained in the step (H), to the fixing layer between the chips of some of the P-type thermoelectric conversion material attached to the fixing layer on the second support obtained in the step (D); A method for arranging chips of thermoelectric conversion material, comprising:

2. 2. The method for arranging chips of thermoelectric conversion material according to claim 1, wherein the fixing layer is a fixing layer capable of absorbing laser light, and the steps (C) and (G) are carried out in this order by irradiating the laser light to at least a portion of the fixing layer in each region where some of the P-type thermoelectric conversion material chips and some of the N-type thermoelectric conversion material chips are attached.

3. The method for arranging chips of thermoelectric conversion material according to claim 1 or 2, wherein the fixing layer includes an adhesive layer.

4. 3. The method for arranging chips of thermoelectric conversion material according to claim 2, wherein the fixing layer capable of absorbing laser light is an adhesive layer containing a colorant or a metal filler.

5. 2. The method for arranging chips of thermoelectric conversion material according to claim 1, wherein a thermally expandable substrate is used as the support in one or both of the steps (C) and (G).

6. 2. The method for arranging chips of thermoelectric conversion material according to claim 1, wherein the fixing layer contains thermally expandable particles in one or both of the steps (C) and (G).

7. The method for arranging chips of thermoelectric conversion material according to any one of claims 1 to 6, wherein the chips of thermoelectric conversion material are made of a thermoelectric semiconductor composition, and the thermoelectric semiconductor composition contains a thermoelectric semiconductor material, a resin, and one or both of an ionic liquid and an inorganic ionic compound.

8. A method for producing a chip array of thermoelectric conversion material, comprising the step of carrying out the method according to any one of claims 1 to 7.

9. A method for producing a thermoelectric conversion module containing chips of a thermoelectric conversion material, comprising a step of carrying out the method according to any one of claims 1 to 7.

Images