JP2017179257A - Stress relaxation agent, adhesive for assembling connection structure, joint material for assembling connection structure, semiconductor device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stress relaxation agent that hardly causes the occurrence of a crack or the like in a connection layer and can suppress the occurrence of warpage and peeling of a junction object member even if exposed to a cold heat cycle condition in a reliability test of a semiconductor device and to provide an adhesive for assembling a semiconductor device.SOLUTION: The stress relaxation agent is used in an adhesive for assembling a semiconductor device. The stress relaxation agent includes particles containing a first chain polymer and a cyclic molecule. The cyclic molecule can have a polymerizable functional group and the first chain polymer can penetrate through an opening of the cyclic molecule. The stress relaxation agent has excellent stress relaxation performance and even if a stress is applied to a connection layer formed by curing an adhesive for assembling a semiconductor device, the connection layer can be deformed by following the stress. Consequently, it is difficult to cause damage such as a crack or the like to the connection layer.SELECTED DRAWING: None

Description

  The present invention relates to a stress relaxation agent, an adhesive for assembling a connection structure, a bonding material for assembling a connection structure, a semiconductor device, and an electronic apparatus.

  In a non-insulated semiconductor device that is one of power semiconductor devices used for an inverter or the like, a member for fixing a semiconductor element is also one of electrodes of the semiconductor device. For example, in a semiconductor device in which a power transistor is mounted on a fixing member using an Sn—Pb soldering material, a fixing member (base material) connecting two connection target members serves as a collector electrode of the power transistor. .

  In recent years, a method of assembling a connection structure by connecting two connection target members using a low-temperature firing function of metal particles is known. This is because when the particle size of the metal particles is reduced to a size of 100 nm or less and the number of constituent atoms is reduced, the surface area ratio to the volume of the particles increases rapidly, and the melting point or sintering temperature is significantly higher than in the bulk state. This utilizes the property of the metal particles to be lowered. For example, metal particles having an average particle size of 100 nm or less whose surface is coated with an organic material are used as a connection material, and a connection layer is formed by decomposing the organic material by heating and sintering the metal particles, thereby connecting two connections. The target member can be connected. In such a connection method, since the metal particles after the connection are changed to a bulk metal, a connection by metal bonding is obtained at the connection interface, so that heat resistance, connection reliability, and heat dissipation can be further improved.

  Since the connection layer may be cracked due to heat generation of the connection structure (for example, a semiconductor device) to cause separation of the connection target member, various connection materials have been proposed to prevent this. For example, Patent Document 1 proposes a technique for effectively radiating heat using a composite material having a heat conductive metal having a melting point and silicone particles dispersed in the heat conductive metal. Patent Document 2 discloses a technique for obtaining a highly reliable electric device by using a bonding agent for electronic components including spacer particles to maintain the distance between bonded electronic components with high accuracy.

JP 2013-243404 A Japanese Patent No. 4213767

  However, in the reliability test of the connection structure, when the connection layer connecting the two connection target members is exposed to the thermal cycle condition, the connection target member may be warped and peeled due to the difference in the coefficient of linear expansion. It was a problem. Even in the technologies disclosed in Patent Documents 1 and 2, when exposed to the cooling and heating cycle conditions in the reliability test, the connection layer is likely to crack, and as a result, the connection target member is peeled off and warped. It was.

  The present invention has been made in view of the above, and even when exposed to a cooling cycle condition in a reliability test of a connection structure such as a semiconductor device, a crack or the like is unlikely to occur in the connection layer, and the warp of the connection target member It is another object of the present invention to provide a stress relaxation agent capable of suppressing the occurrence of peeling, an adhesive for assembling a connection structure, and a bonding material for assembling a connection structure. Another object of the present invention is to provide a semiconductor device formed using an adhesive for assembling a connection structure or a bonding material for assembling a connection structure, and an electronic device including the semiconductor device.

  In order to achieve the above object, the present inventor considered that it is important to relieve the stress applied to the connection layer in order to prevent cracks in the connection layer formed for assembling the semiconductor device. As a result of extensive research, the inventors have found that the above object can be achieved by forming particles contained in the stress relaxation agent with specific components, and have completed the present invention.

That is, the present invention includes, for example, the subject matters described in the following sections.
Item 1. Used for bonding materials or adhesives for assembling connection structures,
A stress relaxation agent comprising particles containing a first chain polymer and a cyclic molecule.
Item 2. Item 2. The stress relaxation agent according to Item 1, wherein the cyclic molecule has a polymerizable functional group.
Item 3. Item 3. The stress relaxation agent according to Item 1 or 2, wherein the first chain polymer penetrates through an opening of the cyclic molecule.
Item 4. Item 4. The stress relieving agent according to Item 3, wherein a molecule for preventing the cyclic molecule from dropping is bonded to the first chain polymer.
Item 5. The particles further include a second chain polymer,
The stress relaxation agent according to any one of Items 1 to 4, wherein the second chain polymer is bonded to the cyclic molecule to form a crosslinked structure.
Item 6. The content of the first chain polymer and the cyclic molecule is 1% by weight or more and 70% by weight based on the total amount of the first chain polymer, the cyclic molecule and the second chain polymer. % Stress relaxation agent of any one of said claim | item 1-5 which is% or less.
Item 7. Item 7. The stress relaxation agent according to Item 6, wherein the second chain polymer includes at least one of an acrylic polymer and a styrene polymer.
Item 8. Item 8. The stress relaxation agent according to any one of Items 1 to 7, wherein the particle is coated with at least one material selected from the group consisting of a metal material, an inorganic material, and an organic material.
Item 9. The stress relaxation agent according to any one of Items 1 to 8, wherein an average particle diameter of the particles is less than ½ of a thickness of a connection layer that is a cured product of the bonding material or adhesive.
Item 10. The stress relaxation agent according to any one of Items 1 to 8, wherein an average particle diameter of the particles is 0.1 μm or more and 15 μm or less.
Item 11. Item 11. An adhesive for assembling a connection structure, comprising the stress relaxation agent according to any one of items 1 to 10.
Item 12. A semiconductor device comprising a connection layer that is a cured product of the adhesive according to Item 11.
Item 13. The joining material for connection structure assembly containing the stress relaxation agent of any one of said items 1-10.
Item 14. 14. A semiconductor device comprising a connection layer that is a cured product of the bonding material according to item 13.
Item 15. Item 15. An electronic device including the semiconductor device according to Item 12 or 14.

  The stress relaxation agent of the present invention is used for a bonding material or an adhesive for assembling a connection structure, and has flexibility, and therefore has excellent stress relaxation performance. For this reason, even if stress is applied to the connection layer formed by curing the bonding material or adhesive containing the stress relaxation agent, the connection layer can be deformed following the stress. Damages such as cracks are unlikely to occur. As a result, warpage and peeling of the bonding target member (for example, a wafer) connected by the bonding material or adhesive containing the stress relaxation agent are suppressed.

  Since the connecting structure assembling material or the connecting structure assembling adhesive of the present invention contains the stress relieving agent, the cured connection layer is unlikely to be damaged such as cracks. Suitable material.

It is a schematic sectional drawing which shows an example of embodiment of a connection structure.

  Hereinafter, embodiments of the present invention will be described in detail.

(Stress relaxation agent)
The stress relaxation agent of the present embodiment is a material used for a bonding material or an adhesive for assembling a connection structure, and includes particles containing a first chain polymer and a cyclic molecule. The connecting structure assembling material or the connecting structure assembling adhesive containing the stress relaxation agent can be used for connecting the members to be connected in assembling the semiconductor device. Since the connection layer formed by curing the connection structure assembly bonding material or the connection structure assembly adhesive includes a stress relaxation agent, the connection layer is unlikely to be damaged such as cracks. Therefore, the stress relaxation agent of the present embodiment makes it possible to suppress warping and peeling of the connected adhesion target member, and in particular, warpage during a cooling / heating cycle when assembling a connection structure such as a semiconductor device and the like. It is effective in suppressing peeling.

  Hereinafter, the particles contained in the stress relaxation agent are referred to as “base particles”.

  The base particle includes a first chain polymer and a cyclic molecule as constituent components. In the following description, “(meth) acryl” means one or both of “acryl” and “methacryl”, and “(meth) acrylate” means one or both of “acrylate” and “methacrylate”. means.

  The kind of 1st chain polymer is not specifically limited, For example, the various polymer conventionally known is employable.

  For example, as the first chain polymer, polyethylene glycol, polypropylene glycol, polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, poly (meth) acrylic acid, poly (meth) acrylamide, cellulose resin such as hydroxyethyl cellulose, polyvinyl acetal type Resin, polyvinyl methyl ether, polyamine, polyethyleneimine, casein, gelatin, polysiloxanes such as polydimethylsiloxane, starch etc. and / or copolymers thereof, polyethylene, polypropylene and copolymer resins with other olefinic monomers Polyolefin resins such as polyester resins, polyvinyl chloride resins, polystyrene resins such as polystyrene and acrylonitrile-styrene copolymer resins, ) Acrylic resin such as acrylate, (meth) acrylic acid ester copolymer, acrylonitrile-methyl acrylate copolymer resin, polycarbonate resin, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, polyvinyl butyral resin, etc .; and derivatives thereof Or modified products, polyisobutylene, polytetrahydrofuran, polyaniline, acrylonitrile-butadiene-styrene copolymer, polyamides such as nylon, polyimides, polydienes such as polyisoprene and polybutadiene, polysulfones, polyimines, polyacetic anhydrides, Examples include polyureas, polysulfides, polyphosphazenes, polyketones, polyphenylenes, and polyhaloolefins. Further, the first chain polymer may be a derivative of various polymers listed above.

  The first chain polymer may be only one kind of polymer, or may contain two or more kinds of polymers. The first chain polymer may be a homopolymer composed of one type of repeating structural unit or a copolymer composed of two or more types of repeating structural units. When the first chain polymer is a copolymer, it may have any structure such as a random copolymer, a block copolymer, and an alternating copolymer.

  The weight average molecular weight of the first chain polymer is not particularly limited, but can be, for example, 3,000 or more, preferably 5,000 to 100,000, and 10,000 to 50,000. 000 is particularly preferred.

  Examples of the cyclic molecule include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, dimethylcyclodextrin, glucosylcyclodextrin and derivatives or modified products thereof, other cyclic oligomers, cyclic Macromonomer etc. are mentioned. Examples of cyclic oligomers include ethylene glycol oligomers, ethylene oxide oligomers, propylene glycol oligomers, and polysaccharides. The cyclic molecule may be only one type or may contain two or more types.

  The cyclic molecule may have a polymerizable functional group. The polymerizable functional group here refers to a functional group that can be polymerized with a polymerizable monomer. Examples of the polymerization include various conventional polymerizations such as radical polymerization, ionic polymerization, polycondensation (condensation polymerization, condensation polymerization), addition condensation, living polymerization, living radical polymerization, and the like.

Specific examples of the polymerizable functional group include alkenyl group and vinyl group, as well as —OH, —SH, —NH ₂ , —COOH, —SO ₃ H, and —PO ₄ H. These may further have one or more substituents. As the polymerizable functional group, a radical polymerizable functional group such as an alkenyl group and a vinyl group is preferable from the viewpoint of easily forming a crosslinked structure described later. The cyclic molecule may have a functional group other than the polymerizable functional group.

  As another example of the cyclic molecule having a polymerizable functional group, the following general formula (1)

(In the above formula, R5 and R6 are each independently hydrogen or an alkyl group having 1 or 2 carbon atoms, R7 is hydrogen or a methyl group, and M is a substituted or unsubstituted carbon. N represents an alkylene group having a number of 2 to 4, and n represents the number of repeating units of the structure in parentheses, and is an integer of 5 to 100. Further, n + 1 Ms may be the same or different. Good.)
The cyclic macromonomer represented by these is mentioned.

  As still another example of the cyclic molecule having a polymerizable functional group, the following general formula (2)

(In the above formula, M represents a substituted or unsubstituted alkylene group having 2 to 4 carbon atoms, n represents the number of repeating units of the structure in parentheses, and is an integer of 5 to 100. In addition, n + 1 M May be the same or different from each other).

  As long as the base particles contained in the stress relaxation agent include the first chain polymer and the cyclic molecule, the presence mode of each molecule is not particularly limited.

  However, it is preferable that the first chain polymer penetrates the opening of the cyclic molecule from the viewpoint that the performance of relieving stress by the stress relaxation agent can be further enhanced. That is, it is preferable that the first chain polymer penetrates the ring of the cyclic molecule, and the first chain polymer and the cyclic molecule form a so-called inclusion compound.

  The structure in which the first chain polymer is formed through the opening of the cyclic molecule as described above is referred to as “polyrotaxane”.

  When the base particle contained in the stress relaxation agent contains polyrotaxane, the first chain polymer is polyethylene glycol, polyisoprene, polyisobutylene, polybutadiene, polypropylene glycol, polytetrahydrofuran, polydimethylsiloxane, polyethylene, polypropylene, polyvinyl At least one selected from the group consisting of alcohol and polyvinyl methyl ether is preferred. In this case, the first chain polymer easily penetrates through the opening (in the ring) of the cyclic molecule, and easily forms a stable polyrotaxane. Note that the first chain polymer may have a branched chain to the extent that it can penetrate the opening of the cyclic molecule.

  When the base particle contained in the stress relaxation agent contains polyrotaxane, the cyclic molecule is preferably a molecule selected from the group consisting of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

  When the base particle contained in the stress relaxation agent contains polyrotaxane, when the amount of the cyclic molecule that is included to the maximum when the linear molecule penetrates the cyclic molecule is 1, the penetration amount of the cyclic molecule is It can be 0.001-0.6, preferably 0.01-0.5, more preferably 0.05-0.4. The maximum inclusion amount of the cyclic molecule can be determined by a known method.

  When the base particle contained in the stress relaxation agent contains polyrotaxane, it is preferable that a molecule for preventing the cyclic molecule from dropping is bonded to the first chain polymer. Hereinafter, the molecule bonded to the first chain polymer in order to prevent the cyclic molecule from dropping is referred to as a stopper group.

  Examples of the stopper group include aryl groups such as adamantane group, dinitrophenyl group, cyclodextrins, N-carbobenzoxy-L-tyrosine (ZL-tyrosine), trityl group, pyrenyl group, and phenyl group. , 2-butyldecyl group, fluoresceins, pyrenes, and derivatives or modified products thereof. In addition, in the polyrotaxane, there is a conventionally known functional group for preventing the cyclic molecule from dropping off. The stopper groups listed above may have a substituent.

  The stopper group is bonded to both ends of the first chain polymer, for example. When such bulky stopper groups are bonded to both ends of the first chain polymer, the state in which the cyclic molecule is penetrated in a skewered manner by the first chain polymer can be maintained. That is, the cyclic molecule can move freely while including the first chain polymer, and is not detached from the first chain polymer by the stopper groups at both ends. Thereby, it becomes easy to exhibit the more excellent stress relaxation effect.

  The stopper group may be directly bonded to both ends of the first chain polymer, or indirectly bonded to both ends of the first chain polymer via an amide bond, an ester bond, or the like. You may do it.

  The base particle may be a mixture of the first chain polymer having a stopper group and the first chain polymer not having a stopper group.

  When the first chain polymer does not have a stopper group, some cyclic molecules may fall off from the first chain polymer. Can continue to exist between the polymer matrices.

  Said base material particle can further contain a 2nd chain polymer.

  Examples of the second chain polymer include polyolefin resins such as polyethylene, polypropylene, polystyrene, silicone resin, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; Alkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene Oxide, polyacetal, polyimide, polyamideimide, polyetheretherketone Polyethersulfone, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof.

  In particular, the second chain polymer preferably contains at least one of an acrylic polymer and a styrene polymer. In this case, the stress relaxation effect of the stress relaxation agent is more excellent, and the production of the base particles can also be performed by a simple method. In particular, the second chain polymer is preferably an acrylic polymer.

  The second chain polymer may be a homopolymer composed of one type of repeating structural unit or a copolymer composed of two or more types of repeating structural units. When the first chain polymer is a copolymer, it may have any structure such as a random copolymer, a block copolymer, and an alternating copolymer.

  From the viewpoint of easily controlling the hardness of the substrate particles within a suitable range, the second chain polymer is preferably a polymer of a polymerizable monomer having a plurality of ethylenically unsaturated groups. The second chain polymer may be a polymer of only one kind of polymerizable monomer, or may be a polymer of two or more kinds of polymerizable monomers.

  When the second chain polymer is a polymer of a monomer having an ethylenically unsaturated group, the monomer having the ethylenically unsaturated group includes a non-crosslinkable monomer and a crosslinkable monomer. Monomer.

  Examples of the non-crosslinkable monomer include, as vinyl compounds, styrene monomers such as styrene, α-methylstyrene, and chlorostyrene; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, 1,4-butanediol di Vinyl ethers such as vinyl ether, cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether; acid vinyl esters such as vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate; halogen-containing monomers such as vinyl chloride and vinyl fluoride ; As a (meth) acryl compound, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) Alkyl (meth) acrylates such as acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, poly Oxyethylene (meth) acrylate, oxygen atom-containing (meth) acrylates such as glycidyl (meth) acrylate; Nitrile-containing monomers such as (meth) acrylonitrile; trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate Halogen-containing (meth) acrylates such as: α-olefin compounds such as diisobutylene, isobutylene, linearene, ethylene, propylene, etc .; Puren, butadiene and the like.

  Examples of the crosslinkable monomer include vinyl compounds such as vinyl monomers such as divinylbenzene, 1,4-divinyloxybutane and divinylsulfone; (meth) acrylic compounds such as tetramethylolmethanetetra ( (Meth) acrylate, polytetramethylene glycol diacrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol Penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; as allyl compounds, triallyl (iso) cyanurate, triallyl trimellitate , Diallyl phthalate, diallyl acrylamide, diallyl ether; tetramethoxysilane, tetraethoxysilane, triethylsilane, t-butyldimethylsilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane as silicone compounds , Isopropyltrimethoxysilane, isobutyltrimethoxysilane, cyclohexyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltriethoxysilane, n Decyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, trimethoxysilylstyrene, γ- (meth) acryloxypropyltrimethoxysilane, 1,3-divinyltetramethyldisiloxane, Silane alkoxides such as methylphenyldimethoxysilane and diphenyldimethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxydimethylvinylsilane, dimethoxyethylvinylsilane, diethoxymethyldivinylsilane, diethoxyethylvinylsilane, ethylmethyldivinylsilane , Methyl vinyl dimethoxy silane, ethyl vinyl dimethoxy silane, methyl vinyl diethoxy silane, ethyl vinyl diethoxy silane p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltri Polymerizable double bond-containing silane alkoxides such as methoxysilane; Cyclic siloxanes such as decamethylcyclopentasiloxane; Modified (reactive) silicone oils such as one-end modified silicone oil, both-end silicone oil, and side chain silicone oil; Examples thereof include carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride.

  Even when the second chain polymer is a polymer of a polymerizable monomer having a plurality of ethylenically unsaturated groups, the resulting polymer contains at least one of an acrylic polymer and a styrene polymer. It is preferable. In this case, the stress relaxation effect of the stress relaxation agent is more excellent, and the production of the base particles can also be performed by a simple method. In particular, the second chain polymer is preferably an acrylic polymer.

  The second chain polymer is produced by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method such as a radical polymerization method.

  The second chain polymer can be bonded to the above cyclic molecule to form a crosslinked structure. That is, the base particle contained in the stress relaxation agent may be formed including a crosslinked structure formed by bonding the second chain polymer and the cyclic molecule. In this case, a crosslinked structure in which cyclic molecules are crosslinked by the second chain polymer is obtained. The cross-linked structure is, for example, a polymer having a branched chain structure or a polymer having a three-dimensional network structure.

  As a specific mode in which the second chain polymer is bonded to the cyclic molecule to form a crosslinked structure, for example, a structure in which the end of the second chain polymer is chemically bonded to the cyclic molecule in the polyrotaxane described above. It is done. Specifically, one end of the second chain polymer is chemically bonded to the cyclic molecule in the polyrotaxane, and the other end of the second chain polymer is chemically bonded to the cyclic molecule in another polyrotaxane. By doing so, the cross-linked structure can be formed. By such crosslinking, a crosslinked structure having a three-dimensional network structure of the polyrotaxane and the second chain polymer is formed.

  As described above, in the crosslinked structure constituting the base particle, the polyrotaxanes can be crosslinked by the second chain polymer. More specifically, in the crosslinked structure constituting the base particle, the cyclic molecules of polyrotaxane can be crosslinked by the second chain polymer.

  In the crosslinked structure of the polyrotaxane and the second chain polymer as described above, the cyclic molecule serves as a starting point (crosslinking point) for crosslinking the second chain polymer. In the polyrotaxane, the cyclic molecule can move freely on the first chain polymer. Therefore, the crosslinking point in the crosslinked structure can move on the first chain polymer. That is, the cross-linked structure is a so-called mobile cross-linking type polymer material. Such a cross-linked structure has flexibility because the cross-linking point moves following it even when stress is applied, and since the stress is easily relaxed, it has superior stretchability and resilience. Has properties.

  Therefore, when the base particle contained in the stress relaxation agent contains the above-mentioned crosslinked structure of polyrotaxane and the second chain polymer as a constituent component, the stress relaxation agent is particularly excellent in stress relaxation. Has performance.

  For this reason, even if stress is applied to the connection layer formed by curing the connection structure assembly bonding material or the connection structure assembly adhesive containing the stress relaxation agent, the connection layer follows the stress. Since it can be deformed, damage such as cracks hardly occurs in the connection layer. As a result, the bonding target member connected by the connection structure assembly bonding material or the connection structure assembly adhesive containing the stress relaxation agent is prevented from warping and peeling.

  In addition, when the first chain polymer constituting the polyrotaxane has a stopper group, the cyclic molecule does not drop out, so that the stress relaxation effect can be maintained over a long period of time. Of course, even when the polyrotaxane is composed of the first chain polymer having no stopper group, the stress relaxation effect can be exhibited.

  The method for producing a crosslinked structure of the polyrotaxane and the second chain polymer as described above is not particularly limited. For example, by reacting a polyrotaxane having a cyclic molecule having a polymerizable functional group with a polymerizable monomer for forming the second chain polymer, the polyrotaxane and the second chain form are reacted. A crosslinked structure with a polymer can be produced. The polymerizable functional group and polymerizable monomer here are as described above.

  For example, if the polymerizable functional group is a functional group capable of radical polymerization with a polymerizable monomer (such as a vinyl group), the polyrotaxane and the second monomer can be subjected to radical polymerization reaction with the polyrotaxane and the polymerizable monomer. A crosslinked structure with a chain polymer can be produced. This radical polymerization reaction can be performed by, for example, a known method.

  The type of polyrotaxane provided with a cyclic molecule having a polymerizable functional group is not particularly limited. For example, “Celum (registered trademark) superpolymer commercially available from Advanced Soft Materials Co., Ltd. “SM3405P”, “Celum® Key Mixture SM3400C”, “Celum® Superpolymer SA3405P”, “Celum® Superpolymer SA2405P”, “Celum® Key Mixture SA3400C”, “ SELM (registered trademark) key mixture SA2400C "," SELM (registered trademark) superpolymer SA3405P "," SELM (registered trademark) superpolymer SA2405P ", and the like. In addition, a polyrotaxane can also be manufactured and used by a well-known manufacturing method, for example.

  In the base particles contained in the stress relaxation agent, the content of the first chain polymer and the cyclic molecule is 1 with respect to the total amount of the first chain polymer, the cyclic molecule, and the second chain polymer. It can be set to 70% by weight or more. If the content of the first chain polymer and the cyclic molecule is the above content, the stress relaxation performance is easily improved. In particular, the base particle is composed of the above polyrotaxane and the second chain polymer. If it contains a crosslinked structure, more excellent stress relaxation performance can be exhibited.

  Therefore, even when the substrate particles include a crosslinked structure of the polyrotaxane and the second chain polymer as described above, the lower limit of the polyrotaxane content is that of the polyrotaxane and the second chain polymer. The amount is preferably 1% by weight, more preferably 5% by weight, and particularly preferably 10% by weight based on the total amount. In addition, when the base particle includes the crosslinked structure of the polyrotaxane and the second chain polymer as described above, the upper limit of the content of the polyrotaxane is relative to the total amount of the polyrotaxane and the second chain polymer. It is preferably 70% by weight, more preferably 50% by weight, and particularly preferably 30% by weight.

  The manufacturing method of the base particle contained in the stress relaxation agent is not particularly limited, and for example, a conventionally known particle manufacturing method can be employed.

  For example, a method of polymerizing a polymerizable starting material for synthesizing base particles in the presence of a polymerization initiator and water can be mentioned. Among them, a method of suspension polymerization of a radical polymerizable starting material in the presence of a polymerization initiator is exemplified. In synthesizing the base particles, a dispersion stabilizer may be used as necessary. In addition, a so-called seed polymerization method, dispersion polymerization method, or the like in which a monomer is swollen together with a radical polymerization initiator using a non-crosslinked seed particle for polymerization.

  When producing base particles composed of a polyrotaxane and a second chain polymer, a polyrotaxane and a radical polymerizable monomer for obtaining the second chain polymer, Examples thereof include a method of suspension polymerization in the presence of a polymerization initiator. Even when the polyrotaxane is formed with a cyclic molecule having a radical polymerizable functional group, the polyrotaxane is polymerized with the radical polymerizable monomer for obtaining the second chain polymer. Suspension polymerization can be carried out in the presence of an initiator. In this case, substrate particles containing a crosslinked structure of polyrotaxane and the second chain polymer are obtained.

  The kind of polymerization initiator is not specifically limited, For example, the compound generally used in suspension polymerization, emulsion polymerization, dispersion polymerization, etc. can be used. Moreover, you may use a dispersion stabilizer etc. in the case of superposition | polymerization as needed. The type of the dispersion stabilizer is not particularly limited, and for example, a known dispersion stabilizer can be used. The polymerization conditions are not particularly limited, and can be performed, for example, under appropriate conditions conventionally known.

  The substrate particles may have a plurality of protrusions on the surface. The method for forming the protrusion is not particularly limited, and for example, a conventionally performed method can be adopted.

  The substrate particles may be coated with at least one material selected from the group of metal materials, inorganic materials, and organic materials.

  Examples of metal materials include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, ruthenium, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, and silicon. And alloys thereof. Examples of the metal include tin-doped indium oxide (ITO) and solder.

  The metal material may be formed as a single layer covering the surface of the base particle, or may be formed as a plurality of layers.

  The method for coating the substrate particles with the metal material is not particularly limited. For example, the substrate particles are made of a metal material by a method by electroless plating, a method by electroplating, a method by physical vapor deposition, or a method of coating the surface of the substrate particles with metal powder or a paste containing a metal powder and a binder. Can be coated. From the viewpoint of simplicity, a method by electroless plating is preferable. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering.

  The thickness of the metal material layer is preferably 0.5 nm or more, more preferably 10 nm or more, preferably 10 μm or less, more preferably 1 μm or less, still more preferably 500 nm or less, and particularly preferably 300 nm or less. The thickness of the metal material indicates the thickness of all layers when it is a multilayer.

  Examples of the inorganic material include, but are not limited to, inorganic compounds such as shirasu particles, hydroxyapatite particles, magnesia particles, zirconium oxide particles, silica particles, alumina particles, and zirconia particles. In addition, as said inorganic material, the particle | grains formed with a well-known inorganic element or an inorganic compound may be sufficient. Examples of the silica particles include pulverized silica and spherical silica. Silica particles may have a functional group capable of chemical bonding such as a carboxyl group and a hydroxyl group on the surface.

  An inorganic material is not limited to the said inorganic particle, For example, the film-form form formed with an inorganic compound may be sufficient. A film formed of such an inorganic compound can be formed by, for example, a known method, but the formation method is not particularly limited. For example, the base particles can be coated with an inorganic material by forming a metal alkoxide into a shell-like material by a sol-gel method in the presence of the base particles. Examples of the metal alkoxide include silane alkoxide, titanium alkoxide, zirconium alkoxide, and aluminum alkoxide.

  The inorganic material may be formed as a single layer covering the surface of the base particle, or may be formed as a plurality of layers.

  Examples of the organic material include resin materials, and specifically, polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, other thermoplastic resins, and thermoplastic resins. Cross-linked products, thermosetting resins, water-soluble resins and the like can be mentioned. In addition, the organic material may be a resin similar to the resin that forms the base particles contained in the stress relaxation agent.

  Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. Examples of the (meth) acrylate polymer include polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof.

  Examples of the thermoplastic resin include the above-listed resins, and other vinyl polymers and vinyl copolymers. As said thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, etc. are mentioned.

  Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose. Of these, water-soluble resins are preferable, and polyvinyl alcohol is more preferable.

  The shape of the resin is not particularly limited. For example, the shape of the resin may be a particle shape or a film shape. The average particle diameter and film thickness of the particles are not particularly limited.

  The organic material may be a polymer electrolyte or the like. As the polymer electrolyte, a polymer (polyanion or polycation) ionized in an aqueous solution and having a charged functional group in the main chain or side chain can be used. Examples of polyanions generally include those having a negatively charged functional group such as sulfonic acid, sulfuric acid, carboxylic acid, and the like, which are appropriately selected according to the surface potential of the conductive particles and the insulating layer. Can do. The polycation generally has a positively charged functional group such as polyamines such as PEI, polyallylamine hydrochloride (PAH), PDDA, polyvinyl pyridine (PVP), polylysine, polyacrylamide. And a copolymer containing at least one of them can be used.

  The organic material may be formed as a single layer covering the surface of the base particle, or may be formed as a plurality of layers.

  The base particles are covered only with any one material selected from the group of metal materials, inorganic materials, and organic materials, so that the base particles are more easily prevented from agglomerating and more effective for stress relaxation. It becomes easy to demonstrate. In addition, by appropriately selecting the material to be coated on the base particles from the group of metal materials, inorganic materials, and organic materials, it is possible to further increase the affinity for the connecting structure assembly bonding material or the connection structure assembly adhesive. Therefore, the dispersibility of the stress relaxation agent in the bonding material or adhesive is improved. Also by this, the stress relaxation agent easily exhibits a high stress relaxation effect.

  The substrate particles may be coated only with any one material selected from the group of metal materials, inorganic materials, and organic materials, or may be coated with a combination of two or more of these materials. Good.

  The average particle diameter of the base particles is not particularly limited, but the average particle diameter of the base particles is used from the viewpoint that the stress relieving agent of the present embodiment is used for the connection structure assembly bonding material or the connection structure assembly adhesive. Is preferably less than 1/2 of the thickness of the connection layer, which is a cured product of the connection structure assembly bonding material or the connection structure assembly adhesive. When the average particle diameter of the substrate particles is as described above, the effect of stress relaxation by the stress relaxation agent is difficult to be impaired, so that cracking and peeling of the connection layer are unlikely to occur, and the adhesive strength of the connection layer is also unlikely to decrease.

  Moreover, it is also preferable that the average particle diameter of a base particle is 0.1 micrometer or more and 15 micrometers or less. Also in this case, since the effect of stress relaxation by the stress relaxation agent is hardly impaired, the occurrence of cracking and peeling of the connection layer in the thermal cycle is less likely to occur, and the adhesion strength of the connection layer is less likely to occur after the thermal cycle test.

  The average particle diameter of the base particles mentioned above means the diameter when the shape is a true sphere, and means the average value of the maximum diameter and the minimum diameter when the shape is a shape other than the true sphere. The average particle diameter of the substrate particles means an average value obtained by observing the substrate particles with a scanning electron microscope and measuring the particle diameters of 50 randomly selected substrate particles with calipers. In addition, the average particle diameter in case the base material particle is coat | covered with another material as mentioned above also includes the coating layer.

The coefficient of variation (CV value) of the particle diameter of the substrate particles is, for example, 50% or less. The coefficient of variation (CV value) is expressed by the following equation.
CV value (%) = (ρ / Dn) × 100
ρ: standard deviation of particle diameter of particle Dn: average value of particle diameter of particle

  From the viewpoint of further suppressing the occurrence of cracks or peeling in the cooling and heating cycle, the CV value of the particle diameter of the base particles is preferably 40% or less, more preferably 30% or less. The lower limit of the CV value of the particle diameter of the substrate particles is not particularly limited. The CV value may be 0% or more, 5% or more, 7% or more, or 10% or more.

The hardness of the substrate particles is not particularly limited, and can be, for example, 10 to 1000 N / mm ² with a 10% K value. In this case, the stress relaxation effect by the stress relaxation agent is easily exhibited, and the occurrence of cracks or peeling of the connection layer in the thermal cycle is likely to be suppressed.

The 10% K value referred to here is a compression elastic modulus when the substrate particles are compressed by 10%. It can be measured as follows. First, using a micro-compression tester, base material particles are compressed under a condition that a smooth tester end face of a cylinder (diameter 50 μm, made of diamond) is loaded at 25 ° C. and a maximum test load 20 mN over 60 seconds. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula.
10% K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the particles are 10% compressively deformed (N)
S: Compression displacement (mm) when the particles are 10% compressively deformed
R: radius of particle (mm)

As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used. In addition, also when calculating | requiring a 30% K value, it can calculate by calculating | requiring each said parameter when carrying out 30% compression deformation of particle | grains.

  It is preferable that the base particle has 100 or less aggregated particles per 1 million particles. The agglomerated particles are particles in which one particle is in contact with at least one other particle. For example, when 1 million base particles include 3 particles in which 3 particles are aggregated (aggregates of 3 particles), the aggregated particles per 1 million base particles The number is nine. As a method of measuring the aggregated particles, a method of counting aggregated particles using a microscope set with a magnification so that about 50,000 particles are observed in one field of view, and measuring aggregated particles as a total of 20 fields of view, etc. Is mentioned.

  The substrate particles preferably have a thermal decomposition temperature of 200 ° C. or more. In this case, when forming the connection layer using the connection structure assembly bonding material or the connection structure assembly adhesive, Thermal decomposition is likely to be suppressed. The thermal decomposition temperature of the base particles is preferably 220 ° C. or higher, more preferably 250 ° C. or higher, and further preferably 300 ° C. or higher. In addition, when base material particle | grains have the above-mentioned coating layer, let the temperature which thermally decomposes first among base material particle | grains and the said coating layer be the thermal decomposition temperature of base material particle | grains.

  The stress relieving agent of the present embodiment may be composed of only the above-mentioned base particles, and may contain other materials as long as the stress relieving effect is not hindered.

(Joint for connecting structure assembly)
The joining material for assembling a connection structure according to the present embodiment includes the stress relaxation agent. According to the joint material for assembling a connection structure according to the present embodiment, it is possible to form a connection layer that connects two connection target members for constituting a connection structure such as a semiconductor device.

  As long as the joining material for connecting structure assembly contains the above-described stress relaxation agent, other components are not particularly limited. For example, the components included in the joining material conventionally used for assembling the connecting structure include Can be mentioned.

  For example, the connection structure assembling material further includes metal atom-containing particles in addition to the stress relaxation agent.

  Examples of the metal atom-containing particles include metal particles and metal compound particles. The metal compound particle includes a metal atom and an atom other than the metal atom. Specific examples of the metal compound particles include metal oxide particles, metal carbonate particles, metal carboxylate particles, and metal complex particles. The metal compound particles are preferably metal oxide particles. For example, the metal oxide particles are sintered after becoming metal particles by heating at the time of connection in the presence of a reducing agent. The metal oxide particles are metal particle precursors. Examples of the metal carboxylate particles include metal acetate particles.

Examples of the metal constituting the metal particle and the metal oxide particle include silver, copper, and gold. Silver or copper is preferred, and silver is particularly preferred. Therefore, the metal particles are preferably silver particles or copper particles, and more preferably silver particles. The metal oxide particles are preferably silver oxide particles or copper oxide particles, and more preferably silver oxide particles. When silver particles and silver oxide particles are used, there are few residues after connection and the volume reduction rate is very small. Examples of the silver oxide in the silver oxide particles include Ag ₂ O and AgO.

  The average particle diameter of the metal atom-containing particles is preferably 10 nm or more and 10 μm or less. Moreover, it is preferable to have 2 or more types of metal atom containing particle | grains from which an average particle diameter differs from a viewpoint of raising the connection intensity | strength of a connection object member. In the case of having two or more kinds of metal atom-containing particles having different average particle diameters, the average particle diameter of the metal atom-containing particles having a small average particle diameter is preferably 10 nm or more, and preferably 100 nm or less. The average particle size of the metal atom-containing particles having a large average particle size is preferably 1 μm or more, and preferably 10 μm or less. The ratio of the compounding amount of the metal atom-containing particles having a small average particle size to the metal atom-containing particles having a large average particle size is preferably 1/9 or more and 9 or less. The average particle diameter of the metal atom-containing particles can be determined by observing the particles with a scanning electron microscope and arithmetically averaging the maximum diameters of 50 arbitrarily selected particles in the observed image.

  The metal atom-containing particles are preferably sintered by heating at less than 400 ° C. The temperature at which the metal atom-containing particles are sintered (sintering temperature) is more preferably 350 ° C. or lower, and preferably 300 ° C. or higher. When the temperature at which the metal atom-containing particles are sintered is equal to or lower than the upper limit or lower than the upper limit, sintering can be efficiently performed, energy required for sintering is further reduced, and environmental load is reduced. be able to.

  When the metal atom-containing particles are metal oxide particles, a reducing agent is preferably used. Examples of the reducing agent include alcohols (compounds having an alcoholic hydroxyl group), carboxylic acids (compounds having a carboxy group), amines (compounds having an amino group), and the like. As for the said reducing agent, only 1 type may be used and 2 or more types may be used together.

  Examples of the alcohols include alkyl alcohols. Specific examples of the alcohols include, for example, ethanol, propanol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol. , Pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, nonadecyl alcohol and icosyl alcohol. The alcohols are not limited to primary alcohol compounds, but secondary alcohol compounds, tertiary alcohol compounds, alkane diols, and alcohol compounds having a cyclic structure can also be used. Furthermore, as the alcohols, compounds having many alcohol groups such as ethylene glycol and triethylene glycol may be used. Moreover, you may use compounds, such as a citric acid, ascorbic acid, and glucose, as said alcohol.

  Examples of the carboxylic acids include alkyl carboxylic acids. Specific examples of the carboxylic acids include butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid , Octadecanoic acid, nonadecanoic acid and icosanoic acid. The carboxylic acids are not limited to primary carboxylic acid type compounds, but secondary carboxylic acid type compounds, tertiary carboxylic acid type compounds, dicarboxylic acids, and carboxyl compounds having a cyclic structure can also be used.

  Examples of the amines include alkyl amines. Specific examples of the amines include butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, Examples include heptadecylamine, octadecylamine, nonadecylamine and icodecylamine. The amines may have a branched structure. Examples of amines having a branched structure include 2-ethylhexylamine and 1,5-dimethylhexylamine. The amines are not limited to primary amine compounds, and secondary amine compounds, tertiary amine compounds, and amine compounds having a cyclic structure can also be used.

  The reducing agent may be an organic substance having an aldehyde group, an ester group, a sulfonyl group or a ketone group, or may be an organic substance such as a carboxylic acid metal salt. While the carboxylic acid metal salt is used as a precursor of metal particles, it also contains an organic substance, so that it is also used as a reducing agent for metal oxide particles.

  The content of the reducing agent is preferably 1 part by weight or more, more preferably 10 parts by weight or more, preferably 1000 parts by weight or less, more preferably 500 parts by weight with respect to 100 parts by weight of the metal oxide particles. Hereinafter, it is more preferably 100 parts by weight or less. When the content of the reducing agent is not less than the above lower limit, the metal atom-containing particles can be sintered more densely. As a result, heat dissipation and heat resistance in the connection layer are also increased.

  When a reducing agent having a melting point lower than the sintering temperature (connection temperature) of the metal atom-containing particles is used, there is a tendency that aggregation occurs at the time of connection and voids are easily generated in the connection layer. By using the carboxylic acid metal salt, the carboxylic acid metal salt is not melted by the heating at the time of connection, so that generation of voids can be suppressed. In addition to the carboxylic acid metal salt, a metal compound containing an organic substance may be used as the reducing agent.

  If the bonding material for assembling the connection structure according to this embodiment is used, the connection layer can be formed by solidifying the metal atom-containing particles after melting them. The metal atom-containing particles do not contain the stress relaxation agent.

  The melting point of the metal atom-containing particles is preferably lower than the thermal decomposition temperature of the stress relaxation agent. Specifically, the melting point of the metal atom-containing particles is preferably 10 ° C. or more lower than the thermal decomposition temperature of the stress relaxation agent, more preferably 30 ° C. or more, and most preferably 50 ° C. or more.

  It is preferable that the joining material for assembling the connection structure includes a resin, and in this case, generation of cracks or peeling in a cooling / heating cycle can be further suppressed.

  The resin is not particularly limited. The resin preferably includes a thermoplastic resin or a curable resin, and more preferably includes a curable resin. Examples of the curable resin include a photocurable resin and a thermosetting resin. The photocurable resin preferably contains a photocurable resin and a photopolymerization initiator. The thermosetting resin preferably contains a thermosetting resin and a thermosetting agent. Examples of the resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. As for the said resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. Examples of the thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogenated product of a styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

  From the viewpoint of further suppressing the occurrence of cracks or peeling in the cooling and heating cycle, it is preferable that the connecting material for assembling the connection structure includes an epoxy resin.

  In the joining material for assembling the connection structure, the content of the metal atom-containing particles is preferably larger than the content of the stress relaxation agent, and in this case, the stress relaxation effect is easily exhibited. The content of the metal atom-containing particles is more preferably 10% by weight or more, and more preferably 20% by weight or more, more than the content of the stress relaxation agent.

  In the connection structure assembly bonding material, the content of the stress relaxation agent is not limited, but the dispersion medium of the connection structure assembly bonding material is excluded from the viewpoint of easily suppressing the occurrence of cracks or delamination in the thermal cycle. It can be 1 volume% or more in 100 volume% of components, Preferably it is 10 volume% or more, More preferably, it is 20 volume% or more. Moreover, it can be 50 volume% or less in 100 volume% of components except the dispersion medium of the joining material for connection structure assembly, Preferably it is 40 volume% or less, More preferably, it is 30 volume% or less. It is. The dispersion medium is removed by volatilization.

  In the connection structure assembly bonding material, the content of the metal atom-containing particles is not limited, but from the viewpoint of easily suppressing the occurrence of cracks or delamination in the cooling and heating cycle, the dispersion medium of the connection structure assembly bonding material In 100% by weight of the component excluding the above, it can be 70% by weight or more, more preferably 80% by weight or more, and 98% by weight or less, more preferably 95% by weight or less.

  When the bonding material for connecting structure assembly includes a resin, the content of the resin is not limited, but from the viewpoint of easily suppressing the occurrence of cracking or peeling in the cooling cycle, the dispersion medium for the bonding material for connecting structure assembly In 100% by weight of the components excluding the above, it can be 1% by weight or more, preferably 5% by weight or more, and 20% by weight or less, more preferably 15% by weight or less.

  In addition to the above components, the connecting structure assembling material may contain other components as long as the effects of the present invention are not impaired. Examples of other components include solvents, coupling agents, antifoaming agents, curing aids, stress reducing agents, colorants such as pigments and dyes, light stabilizers, surfactants, and other various additives. . Each of these additives may be used alone or in combination of two or more.

  Since the joint material for assembling the connection structure according to this embodiment includes the stress relaxation agent, damage such as cracks is unlikely to occur in the connection layer formed by curing the adhesive. For this reason, even when various connection target members, which are components of the connection structure, are bonded to each other using the connection structure assembly bonding material, the connection target member is hardly warped and peeled off. The bonding material is an adhesive suitable for assembling the connection structure.

(Adhesive for connecting structure assembly)
The adhesive for assembling a connection structure according to this embodiment includes the above-described stress relaxation agent. According to the adhesive for assembling a connection structure according to the present embodiment, it is possible to form a connection layer that connects two connection target members for constituting a connection structure such as a semiconductor device.

  As long as the adhesive for assembling the connection structure contains the above-mentioned stress relaxation agent, other components are not particularly limited. For example, the components contained in the adhesive that has been conventionally used for assembling the connection structure are included. Can be mentioned.

  For example, the adhesive for assembling the connection structure further includes metal atom-containing particles in addition to the stress relaxation agent.

  The kind of metal atom containing particle | grains is not specifically limited, For example, silver powder is mentioned. Thermal conductivity can be provided because the adhesive for assembling the connection structure contains silver powder. The kind of silver powder is not specifically limited, It can be made to be the same as that of the silver powder conventionally used in order to assemble a connection structure. Note that the adhesive for assembling the connection structure may further contain other metal components in addition to the silver powder.

  The adhesive for assembling the connection structure can contain a resin component and a solvent.

  The resin is not particularly limited. The resin preferably includes a thermoplastic resin or a curable resin, and more preferably includes a curable resin. Examples of the curable resin include a photocurable resin and a thermosetting resin. The photocurable resin preferably contains a photocurable resin and a photopolymerization initiator. The thermosetting resin preferably contains a thermosetting resin and a thermosetting agent. Examples of the resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. As for the said resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. Examples of the thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogenated product of a styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

  From the viewpoint of further suppressing the occurrence of cracks or peeling in the cooling and heating cycle, it is preferable that the connecting material for assembling the connection structure includes an epoxy resin.

  The type of the solvent is not particularly limited, and can be the same as the solvent conventionally used as an adhesive for assembling the connection structure.

  In the adhesive for assembling the connection structure, the content of the metal atom-containing particles is preferably larger than the content of the stress relaxation agent, and in this case, the stress relaxation effect is easily exhibited. The content of the metal atom-containing particles is more preferably 10% by weight or more, and more preferably 20% by weight or more, more than the content of the stress relaxation agent.

  In the adhesive for assembling the connection structure, the content of the stress relaxation agent is not limited, but from the viewpoint that it is easy to suppress the occurrence of cracks or peeling in the thermal cycle, the dispersion medium of the adhesive for assembling the connection structure is excluded. It can be 1 volume% or more in 100 volume% of components, Preferably it is 10 volume% or more, More preferably, it is 20 volume% or more. Moreover, it can be 50 volume% or less in 100 volume% of components except the dispersion medium of the adhesive for assembly of connection structure, Preferably it is 40 volume% or less, More preferably, it is 30 volume% or less. It is. The dispersion medium is removed by volatilization.

  In the adhesive for assembling a connection structure, the content of the metal atom-containing particles is not limited. However, from the viewpoint of easily suppressing the occurrence of cracks or delamination in a thermal cycle, the dispersion medium for the adhesive for assembling the connection structure is used. In 100% by weight of the component excluding the above, it can be 70% by weight or more, more preferably 80% by weight or more, and 98% by weight or less, more preferably 95% by weight or less.

  When the adhesive for assembling the connection structure includes a resin, the resin content is not limited, but from the viewpoint of easily suppressing the occurrence of cracks or delamination in the thermal cycle, the dispersion medium for the adhesive for assembling the connection structure In 100% by weight of the components excluding the above, it can be 1% by weight or more, preferably 5% by weight or more, and 20% by weight or less, more preferably 15% by weight or less.

  The adhesive for assembling the connection structure may contain other components in addition to the above components as long as the effects of the present invention are not impaired. Examples of other components include coupling agents, antifoaming agents, curing aids, stress reducing agents, colorants such as pigments and dyes, light stabilizers, surfactants, and other various additives. Each of these additives may be used alone or in combination of two or more.

  Since the adhesive for assembling a connection structure according to this embodiment includes the stress relaxation agent, damage such as cracks is unlikely to occur in the connection layer formed by curing the adhesive. Therefore, even if various connection target members that are components of the connection structure are bonded using the adhesive for assembling the connection structure, the connection target member is hardly warped and peeled off. The adhesive is a suitable adhesive for assembling the connection structure.

(Connection structure)
The connection structure according to the present embodiment includes a first connection target member, a second connection target member, and a connection layer connecting the first and second connection target members. In the semiconductor device, the connection layer is formed of an adhesive for assembling the upper semiconductor device. The connection layer is formed including a cured product of the adhesive for assembling the connection structure or a cured product of the bonding material for assembling the connection structure. The cured product in the case of the connection structure assembling material is, for example, a fired product (sintered product) formed by heat treatment.

  The structure of the connection structure is not particularly limited, and can be, for example, a known connection structure.

  FIG. 1 is a cross-sectional view schematically showing an example of the connection structure according to the present embodiment. The connection structure A shown in FIG. 1 includes a first connection target member 21, a second connection target member 22, and a connection layer 3 connecting the first and second connection target members 21 and 22. Prepare.

  The connection layer 3 includes the stress relaxation agent 1, the gap control particles 61, and the metal connection part 62 described above.

  In the connection layer 3, one gap control particle 61 is in contact with both the two first and second connection target members 21 and 22. On the other hand, the stress relaxation agent 1 is not in contact with both of the first and second connection target members 21 and 22. Thus, it is preferable that the stress relaxation agent 1 is used in order to form the said connection layer so that both the two said connection object members may not be contacted. That is, it is preferable that one stress relaxation agent 1 is used to form the connection layer so as not to contact at least one of the two connection target members.

  The kind of gap control particle 61 is not specifically limited, For example, a well-known particle | grain is mentioned. The gap control particles 61 may be conductive particles or non-conductive particles. The metal connection part 62 is formed by melting and solidifying the metal atom-containing particles. The metal connection part 62 is a molten solidified product of metal atom-containing particles.

  The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method, the connection structure assembly adhesive or the connection structure assembly bonding material is disposed between the first connection target member 21 and the second connection target member 22. And a method of heating and pressurizing the laminate after obtaining the laminate.

  Specific examples of the connection target member include electronic components such as semiconductor wafers, semiconductor chips, capacitors, and diodes, and electronic components such as printed circuit boards, flexible printed circuit boards, glass epoxy substrates, and glass substrates. It is done.

  At least one of the first connection target member and the second connection target member is preferably a semiconductor wafer or a semiconductor chip.

  The first connection target member may have a first electrode on the surface. The second connection target member may have a second electrode on the surface. Examples of the electrode provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a silver electrode, a titanium electrode, a molybdenum electrode, and a tungsten electrode. When the connection object member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a titanium electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a titanium electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient and the electrode by which the aluminum layer was laminated | stacked on the surface of the metal oxide layer may be sufficient. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

  In the connection structure as described above, in the reliability test, the connection layer connecting the two connection target members is exposed to the thermal cycle condition. In this regard, in the connection structure of the present embodiment, the stress relaxation agent containing particles having the specific structure described above is included in the connection layer, so that the connection layer is not easily cracked or peeled off. Generation | occurrence | production of peeling of the connection object member to comprise, generation | occurrence | production of curvature, etc. does not arise easily.

  The connection structure (for example, a semiconductor device) can be incorporated into various electronic devices.

  The type of electronic device is not particularly limited as long as it includes the connection structure. For example, a pressure sensor is mentioned as an example of an electronic device. An example of the pressure sensor is a capacitive pressure sensor.

  As described above, since the connection structure included in the electronic device is less likely to cause peeling or warping of the connection target member constituting the connection structure even if it is exposed to a thermal cycle condition, Performance is unlikely to decline. In particular, in an electronic device such as a capacitive pressure sensor, when the connection layer of the connection structure is peeled or warped, the sensitivity of the pressure sensor is reduced, but if the connection structure of this embodiment is incorporated, the connection Since peeling and warping of the connection layer between the target members are reduced, the sensitivity of the pressure sensor is unlikely to decrease. In addition, even if the connection layer is deformed by an external stress, for example, due to the stress relaxation effect, the connection layer can be easily restored to the original shape, so that the sensitivity of the pressure sensor is maintained over a long period of time and good measurement accuracy is maintained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to the aspect of these Examples.

(Examples 1-7, Comparative Examples 1-3)
As a polyrotaxane containing a cyclic molecule having a polymerizable functional group, “Celum (registered trademark) SA1313P” (manufactured by Advanced Soft Materials Co., Ltd.) and various polymerizable monomers are blended in amounts (groups) shown in Table 1. 2,2′-azobis (2,4-dimethylvaleronitrile) (manufactured by Nippon Finechem Co., Ltd., hereinafter referred to as “ABN-V”) as a polymerization initiator An oil phase was prepared by adding a mixture of 1 part by weight and 0.5 part by weight benzoyl peroxide. Further, 500 parts by weight of deionized water as an aqueous medium and 100 parts by weight of a 5% by weight aqueous polyvinyl alcohol solution as a dispersant were mixed to prepare an aqueous phase. After the oil phase was dispersed in the aqueous phase to obtain a dispersion, the dispersion was put into a polymerization reactor and controlled to a desired droplet size by adjusting the number of stirring revolutions and the stirring time.

  Thereafter, the temperature was raised to 60 ° C. in the polymerization reactor and stirring was continued. If necessary, 10 parts by weight of a surfactant was added to the suspension, and then the internal temperature of the polymerization reactor was raised to 85 ° C. Stirring was continued. After the suspension was cooled, it was washed and dried by an appropriate method to obtain base particles. By classifying the obtained base material particles, base material particles having an average particle diameter of 3.0 μm were obtained.

  Table 1 shows the average particle size of the base particles obtained in each of the examples and comparative examples.

(Evaluation method)
(1) 10% K value and 30% K value 10% K value of particles was measured using “Fischer Scope H-100” manufactured by Fischer. Regarding the conductive particles, the 10% K value of the particles having a conductive part was measured.

(2) Average particle diameter The base particle was observed with a scanning electron microscope, and the maximum diameter of 50 randomly selected particles in the observed image was measured with a caliper and obtained by arithmetic averaging. .

(3) CV value The base particle was observed with a scanning electron microscope, the standard deviation of the particle size of each of the 50 randomly selected particles in the observed image was determined, and the particle size of the particle was determined by the above formula. CV value was determined.

(4) Recovery rate of base material particles The recovery rate of the obtained base material particles and conductive particles was measured using a micro compression tester (Fischer Scope H-100 manufactured by Fischer). Specifically, after applying a maximum test load of 10 mN to one particle, the load is unloaded. The compression displacement L1 (mm) and the recovery displacement L2 (mm) at this time are measured. From the measured value obtained, the following formula recovery rate (%) = (L2 / L1) × 100
Based on the above calculation.

(5) Connection strength Solid copper frame and PPF (Ni-Pd / Au plated copper frame) using a 4 mm x 4 mm silicon chip and a backside gold chip with a gold vapor deposition layer on the bonding surface, using a resin paste for semiconductors And cured at 200 ° C. for 60 minutes. In addition, the resin paste for semiconductor is added to “Strectbond XN-5A” manufactured by Mitsui Chemicals Co., Ltd. so that the content of the base particles is 10% by weight, and dispersed using a planetary stirrer. Obtained. After curing and moisture absorption treatment (85 ° C., relative humidity 85%, 72 hours), the connection strength at 260 ° C. was measured using a mount strength measuring device. The connection strength was evaluated according to the criterion.

◯: Shear strength is 150 N / cm ² or more ○: Shear strength is 100 N / cm ² or more and less than 150 N / cm ² ×: Shear strength is less than 100 N / cm ²

(6) Cooling cycle characteristics (connection reliability)
The connection structure obtained in the connection strength measurement in the above (5) was heated from −65 ° C. to 150 ° C. and cooled to −65 ° C., and a cooling cycle test was performed for 1000 cycles. The presence or absence of cracks and peeling was observed with an ultrasonic flaw detector (SAT). From the occurrence of cracks or peeling, the thermal cycle characteristics were determined according to the following criteria.

[Criteria for cooling cycle characteristics]
◯: Number of cracks and peeling is 0 in 5 samples ○: Number of cracks and peeling is 1 to 2 in 5 samples ×: Number of cracks and peeling is 3 to 5 in 5 samples

Claims (15)

Used for bonding materials or adhesives for assembling connection structures,
A stress relaxation agent comprising particles containing a first chain polymer and a cyclic molecule.   The stress relieving agent according to claim 1, wherein the cyclic molecule has a polymerizable functional group.   The stress relaxation agent according to claim 1 or 2, wherein the first chain polymer penetrates an opening of the cyclic molecule.   The stress relaxation agent according to claim 3, wherein a molecule for preventing the cyclic molecule from falling off is bonded to the first chain polymer. The particles further include a second chain polymer,
The stress relaxation agent according to any one of claims 1 to 4, wherein the second chain polymer is bonded to the cyclic molecule to form a crosslinked structure.   The content of the first chain polymer and the cyclic molecule is 1% by weight or more and 70% by weight with respect to the total amount of the first chain polymer, the cyclic molecule, and the second chain polymer. % Stress relaxation agent according to any one of claims 1 to 5.   The stress relaxation agent according to claim 6, wherein the second chain polymer includes at least one of an acrylic polymer and a styrene polymer.   The stress relaxation agent according to any one of claims 1 to 7, wherein the particles are coated with at least one material selected from the group consisting of a metal material, an inorganic material, and an organic material.   The stress relaxation agent according to any one of claims 1 to 8, wherein an average particle diameter of the particles is less than ½ of a thickness of a connection layer that is a cured product of the bonding material or the adhesive.   The stress relaxation agent according to any one of claims 1 to 8, wherein an average particle diameter of the particles is 0.1 µm or more and 15 µm or less.   The adhesive for connection structure assembly containing the stress relaxation agent of any one of Claims 1-10.   A semiconductor device comprising a connection layer that is a cured product of the adhesive according to claim 11.   The joining material for connection structure assembly containing the stress relaxation agent of any one of Claims 1-10.   A semiconductor device comprising a connection layer that is a cured product of the bonding material according to claim 13.   An electronic apparatus comprising the semiconductor device according to claim 12.