Joint structure

Abstract

To provide a joint structure capable of relaxing a stress applied on a joint layer and capable of suppressing interface peeling of the joint layer.SOLUTION: A joint structure 1 comprises: a first member to be joined 11 having a first joint surface 110; a second member to be joined 12 having a second joint surface 120; and a joint layer 2 joining the first joint surface 110 and the second joint surface 120. The joint layer 2 has a stress relaxation layer 20 containing a chain polymer 200, a first joining molecule layer 21 containing a first joining molecule 210 bound to the first joint surface 110, and a second joining molecule layer 22 containing a second joining molecule 220 bound to the second joint surface 120. One terminal of the chain polymer 200 is bound to the first joining molecule 210 through or without through a first binding molecule 310. The other terminal of the chain polymer 200 is bound to the second joining molecule 220 through or without through a second binding molecule 320.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bonded structure. [Background technology]

[0002] Conventionally, a bonded structure has been known in which the bonding surfaces of two bonded members made of different or the same material are bonded together via a bonding layer. Examples of the material of the bonded members include metal materials, ceramic materials, and resin materials. For example, an adhesive made of a cured product of an adhesive resin composition is commonly used as the bonding layer.

[0003] Furthermore, Patent Document 1 discloses a technology in which a connection layer for connecting two components to be connected is made of a cured adhesive consisting of a stress relaxation agent containing a chain polymer and a cyclic molecule having a polymerizable functional group. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-179257 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally known bonding layers have poor interfacial bonding with the bonded members due to the occurrence of association of adhesive components or reactions between adhesive components during bonding. Poor interfacial bonding can lead to the problem of interfacial peeling due to stress caused by, for example, differences in thermal expansion between the bonded members, even if the bonding layer itself has stress relaxation properties. Even if a stress relaxation agent, such as that disclosed in Patent Document 1, is used, it is difficult to improve interfacial bonding because it cannot contribute to interfacial bonding.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a bonded structure that can relieve stress applied to the bonding layer and suppress interfacial peeling of the bonding layer. [Means for solving the problem]

[0007] One aspect of the present invention is 、 No. The bonding device includes a first bonded member (11) having a first bonding surface (110), a second bonded member (12) having a second bonding surface (120), and a bonding layer (2) that bonds the first bonding surface and the second bonding surface together, The bonding layer is a stress relief layer (20) containing a chain polymer (200); a first bonding molecule layer (21) including first bonding molecules (210) bonded to the first bonding surface; a second bonding molecule layer (22) including second bonding molecules (220) bonded to the second bonding surface, One end of the chain polymer is connected to a first binding molecule (310). Above bound to the first conjugation molecule, The other end of the chain polymer is connected to a second binding molecule (320). Above The second conjugation molecule is bound to And, The chain polymer is derived from a silicone polymer having a silicone chain as the main chain and vinyl groups at both ends, the first adhesive molecule and the second adhesive molecule are both molecules having a triazine ring, an amino group, and a silanol group, The first binding molecule and the second binding molecule are both molecules having a silanol group and an acryloxy group. , Located in the joining structure (1). [Effects of the Invention]

[0008] The bonded structure has the above configuration. Therefore, when stress is applied to the bonding layer, the stress relaxation layer can relax the stress applied to the bonding layer. Furthermore, in the bonded structure, one end of the chain polymer in the stress relaxation layer is bonded to a first bonding molecule bonded to the first bonding surface, with or without a first bonding molecule, and the other end of the chain polymer in the stress relaxation layer is bonded to a second bonding molecule bonded to the second bonding surface, with or without a second bonding molecule, thereby improving the interfacial bonding of the adhesive layer. Therefore, the bonded structure can suppress interfacial peeling of the bonding layer. Therefore, the bonded structure can relax the stress applied to the bonding layer and suppress interfacial peeling of the bonding layer.

[0009] In addition, the symbols in parentheses in the claims and the means for solving the problems indicate the correspondence with the specific means described in the embodiments described below, and do not limit the technical scope of the present invention. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory view schematically showing the joined structure of the first embodiment. [Figure 2] FIG. 2 is an explanatory view schematically showing the joined structure of the second embodiment. [Figure 3] FIG. 3 is an explanatory diagram showing a part of the method for producing the bonded structure of Embodiment 2, in which (a) shows the state before the first binding molecule is bound to the first bonding molecule bound to the first bonding surface, and (b) shows the state after the first binding molecule has been bound to the first bonding molecule bound to the first bonding surface. [Figure 4] 4A and 4B are explanatory views showing a part of the method for manufacturing the bonded structure of the second embodiment, in which FIG. 4A shows the state before the second bonding molecule is bonded to the second bonding surface, and FIG. 4B shows the state after the second bonding molecule has been bonded to the second bonding surface. [Figure 5]FIG. 5 is an explanatory diagram showing a part of the method for producing the bonded structure of the second embodiment, in which (a) shows the state before the second binding molecule is bound to the second bonding molecule bound to the second bonding surface, and (b) shows the state after the second binding molecule has been bound to the second bonding molecule bound to the second bonding surface. [Figure 6] FIG. 6 is an explanatory diagram showing a part of the manufacturing method of the bonded structure of the second embodiment, in which (a) shows the state before one end of the chain polymer is bonded to the first binding molecule, (b) shows the state after one end of the chain polymer has been bonded to the first binding molecule, and (c) is a diagram for explaining the structure of the chain polymer used in (a) and (b). [Figure 7] FIG. 7 is an explanatory diagram showing a part of the method for producing the bonded structure of embodiment 2, in which (a) shows the state before the other end of the chain polymer is bonded to the second binding molecule, and (b) shows the state after the other end of the chain polymer has been bonded to the second binding molecule. [Figure 8] FIG. 8 is an explanatory view showing a part of the manufacturing method of the joined structure of the third embodiment. [Figure 9] FIG. 9 is an explanatory view showing a part of the manufacturing method of the joined structure of the fourth embodiment. [Figure 10] FIG. 10 is a graph showing the tensile shear strength and shear displacement of specimens 1, 1C, 2C, and 3C in Experimental Example 1. [Figure 11] FIG. 11 is a graph showing the tensile shear bond strength and shear displacement of specimens 2, 3, 4C, and 5C in Experimental Example 1. [Figure 12] FIG. 12 is a diagram showing the relationship between the temperature and the thickness ratio of the bonding layer of specimens 8 and 11C in Experimental Example 4. In FIG. [Figure 13] FIG. 13 is a diagram showing the linear expansion coefficients in the lamination direction of the bonding layers of specimens 8 and 11C in Experimental Example 4. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Embodiment 1) The bonded structure of the first embodiment will be described with reference to Fig. 1. As illustrated in Fig. 1, the bonded structure 1 of the present embodiment has a first bonded member 11 having a first bonding surface 110, a second bonded member 12 having a second bonding surface 120, and a bonding layer 2 that bonds the first bonding surface 110 and the second bonding surface 120 together.

[0012] Examples of materials for the first and second members 11 and 12 include metals (including alloys, hereinafter), ceramics, and resins. The first and second members 11 and 12 may be made of the same material or different materials. Examples of combinations of different materials for the first and second members 11 and 12 include metal and ceramic, metal and resin, and ceramic and resin. When the first and second members 11 and 12 are made of different materials, stress is likely to occur due to differences in linear expansion coefficients. This improves interfacial bondability and effectively suppresses interfacial delamination of the bonding layer 2. Even when the first and second members 11 and 12 are made of the same material, heat may be applied to one member but not the other. Even in such a situation, the joined structure 1 of this embodiment can exert the effect of suppressing the interfacial peeling.

[0013] Examples of metal materials include nickel, nickel alloys, zinc, zinc alloys, aluminum, aluminum alloys, iron, iron-based alloys, copper, copper alloys, and silicon. The surface of the metal material may have a natural oxide film, or the natural oxide film may be removed. The surface of the metal material may have a surface treatment layer such as a catalyst layer. The linear expansion coefficient of the metal material may be, for example, 2 to 50 ppm / °C. Examples of ceramic materials include silicon nitride, aluminum nitride, silicon carbide, alumina, glass such as silicon dioxide, and titanium oxide. The surface of the ceramic material may have a surface treatment layer such as an activation layer formed by surface treatment such as corona treatment or plasma treatment. The linear expansion coefficient of the ceramic material may be, for example, 0 to 10 ppm / °C. Examples of resin materials include liquid crystal polymers (LCPs), thermosetting resins (phenolic resins, epoxy resins, silicone resins, etc.), and thermoplastic resins (ester resins, olefin resins, polyphenylene sulfide resins, polyimide resins, polyamide resins, etc.). The resin material may contain additives such as inorganic fillers. The linear expansion coefficient of the resin material may be, for example, 15 to 500 ppm / °C. The linear expansion coefficient of each material can be measured by thermomechanical analysis (TMA). The linear expansion coefficient values are measured at 25°C.

[0014] The first bonding surface 110 and the second bonding surface 120 may both be flat, both may be curved, or one may be flat and the other curved. The first bonding surface 110 may be all or part of the surface of the first member to be bonded 11. The second bonding surface 120 may be all or part of the surface of the second member to be bonded 12.

[0015] In the bonded structure 1, the linear expansion coefficient of the first bonded member 11 and the linear expansion coefficient of the second bonded member 12 can be configured to differ by one order of magnitude or more. This configuration allows for a bonded structure 1 with high stress relaxation and bonding strength, even when the first bonded member 11 and the second bonded member 12 are made of different materials. Furthermore, in the above configuration, when the linear expansion coefficient of the first bonded member 11 is greater than the linear expansion coefficient of the second bonded member 12, the relationship log{(linear expansion coefficient of the first bonded member 11) / (linear expansion coefficient of the second bonded member 12)}>1 is satisfied. Furthermore, when the linear expansion coefficient of the second bonded member 12 is greater than the linear expansion coefficient of the first bonded member 11, the relationship log{(linear expansion coefficient of the second bonded member 12) / (linear expansion coefficient of the first bonded member 11)}>1 is satisfied. Note that log in the above formula is a common logarithm. Specifically, the linear expansion coefficient of ceramic materials such as glass and silicon nitride is approximately 0 to 5 ppm / °C, while the linear expansion coefficient of metal materials such as aluminum and copper is approximately 10 to 20 ppm / °C. Therefore, the above relationship can be satisfied by combining these metal and ceramic materials. The linear expansion coefficients (ppm / °C) of the first member to be joined 11 and the second member to be joined 12 can be measured by thermomechanical analysis (TMA). The linear expansion coefficients are measured at 25°C.

[0016] The bonding layer 2 has a stress relief layer 20, a first bonding molecule layer 21, and a second bonding molecule layer 22. The stress relief layer 20 is a layer including chain polymers 200. The first bonding molecule layer 21 is a layer including first bonding molecules 210 bonded to the first bonding surface 110. The second bonding molecule layer 22 is a layer including second bonding molecules 220 bonded to the second bonding surface 120. In the bonding layer 2, one end of the chain polymer 200 is bonded to the first bonding molecule 210 with or without a first bonding molecule 310. The other end of the chain polymer 200 is bonded to the second bonding molecule 220 with or without a second bonding molecule 320.

[0017] As illustrated in FIG. 1 , the stress relief layer 20 is disposed between a first bonding molecule layer 21 and a second bonding molecule layer 22. FIG. 1 shows an example in which one end of a chain polymer 200 is bonded to a first bonding molecule 310, which is bonded to the first bonding molecule 210, and the other end of the chain polymer 200 is bonded to a second bonding molecule 320, which is bonded to the second bonding molecule 220. FIG. 1 also shows an example in which a first bonding layer 31 is formed between the stress relief layer 20 and the first bonding molecule layer 21, and a second bonding layer 32 is formed between the stress relief layer 20 and the second bonding molecule layer 22. The first bonding layer 31 includes a first bonding molecule 310 that is bonded to one end of the chain polymer 200 and the first bonding molecule 210. The second binding layer 32 includes a second binding molecule 320 that binds to the other end of the chain polymer 200 and the second binding molecule 220 .

[0018] Although not shown, in the bonding layer 2, if one end of the chain polymer 200 is directly bonded to the first bonding molecule 210 without the first bonding molecule 310, the first bonding layer 31 is unnecessary. Similarly, if the other end of the chain polymer 200 is directly bonded to the second bonding molecule 220 without the second bonding molecule 320, the second bonding layer 32 is unnecessary. In other words, the bonding layer 2 may have both the first bonding layer 31 and the second bonding layer 32, or may have either the first bonding layer 31 or the second bonding layer 32, or may not have both the first bonding layer 31 and the second bonding layer 32.

[0019] Suitable chain polymers 200 include a straight-chain polymer having, before both ends are bonded, a functional group at one end that can bond to a first binding molecule 310 and a functional group at the other end that can bond to a second binding molecule 320, and a straight-chain polymer having a functional group at one end that can bond to a first binding molecule 210 and a functional group at the other end that can bond to a second binding molecule 220. Note that Fig. 1 shows an example in which the former chain polymer 200 is used.

[0020] Examples of functional groups at the ends of chain polymer 200 include vinyl groups, acyl groups, silyl groups, carboxy groups, epoxy groups, ethoxysilyl groups, silanol groups, amino groups, and thiol groups. The functional group at one end of chain polymer 200 and the functional group at the other end of chain polymer 200 may be the same or different.

[0021] The chain polymer 200 preferably has elasticity from the viewpoint of enhancing the stress relaxation effect. The main chain constituting the chain polymer 200 can be specifically composed of, for example, a silicone chain, an alkyl chain, an ester chain, an olefin chain, a phenyl alkyl chain, or a copolymer of these chains. Chain polymers 200 composed of such main chains are preferable because they can easily enhance the stress relaxation effect. Figure 1 shows an example in which the chain polymer 200 is linear and extends in the layer stacking direction Z (oriented in the layer stacking direction Z).

[0022] The molecular weight of the chain polymer 200 is preferably 5,000 or more and 150,000 or less. This configuration provides good stretchability for the chain polymer 200, which facilitates enhancing the stress relaxation effect and suppressing interfacial delamination of the bonding layer 2. From the viewpoint of facilitating the above-described effects, the molecular weight of the chain polymer 200 is preferably 6,000 or more, more preferably 10,000 or more, and even more preferably 30,000 or more. The molecular weight of the chain polymer 200 is preferably 140,000 or less, more preferably 120,000 or less, and even more preferably 80,000 or less, from the viewpoints of ensuring the bond density with the first bonding molecules 310 and the second bonding molecules 320 (the bond density with the first bonding molecules 210 and the second bonding molecules 220 when the chain polymer 200 is directly bonded to the first bonding molecules 210 and the second bonding molecules 220) and the bond between the ends of the chain polymer 200, thereby facilitating the suppression of interfacial delamination of the bonding layer 2. The molecular weight of the chain polymer 200 can be measured by gel permeation chromatography (GPC).

[0023] The first bonding molecule 210 can be suitably a molecule having a functional group capable of bonding to the first bonding molecule 310 and a functional group capable of bonding to the first member to be bonded 11 before bonding, a molecule having a functional group capable of bonding to one end of the chain polymer 200, and a molecule having a functional group capable of bonding to the first member to be bonded 11, etc. The second bonding molecule 220 can be suitably a molecule having a functional group capable of bonding to the second bonding molecule 320 and a functional group capable of bonding to the second member to be bonded 12 before bonding, a molecule having a functional group capable of bonding to the other end of the chain polymer 200, and a functional group capable of bonding to the second member to be bonded 12, etc. Examples of the functional group that can bond to one end of the first binding molecule 310 or the chain polymer 200 and the functional group that can bond to the other end of the second binding molecule 320 or the chain polymer 200 include a silanol group, an acryloxy group, a methacryloxy group, an ethoxysilyl group, a thiol group, an epoxy group, an isocyanate group, a silyl group, a carboxy group, a hydroxy group, an acyl group, and an amino group. Examples of the functional group that can bond to the first member to be joined 11 and the second member to be joined 12 include an amino group, a silanol group, an ethoxysilyl group, a thiol group, an epoxy group, an isocyanate group, a silyl group, a carboxy group, a hydroxy group, and an acyl group.

[0024] Examples of the first bonding molecule 210 and the second bonding molecule 220 include molecules having a triazine ring, an amino group, and a silanol group, such as N,N'-bis(2-aminoethyl)-6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine, triethoxysilylpropyltriazinedithiol, and 2,4-diazido-6-(triethoxysilylpropyl)amino-1,3,5-triazine. These molecules can be used alone or in combination. The first bonding molecule 210 and the second bonding molecule 220 may be the same or different. It is preferable that the first bonding molecule 210 and the second bonding molecule 220 contain a triazine ring in order to bond with the first bonding member 11 and the second bonding member 12 and to adsorb at the interface with them at high density.

[0025] In the bonding layer 2, the bond between the first bonding molecules 210 and the first bonding surface 110 and the bond between the second bonding molecules 220 and the second bonding surface 120 are preferably chemical bonds. This configuration makes it easy to increase the interfacial strength between the first bonding surface 110 and the first bonding molecule layer 21 and the interfacial strength between the second bonding surface 120 and the second bonding molecule layer 22. Therefore, this configuration makes it easy to suppress interfacial peeling of the bonding layer 2. Specific examples of chemical bonds include covalent bonds and ionic bonds. These bonds are stronger than hydrogen bonds and the like. Therefore, these bonds can ensure the above-mentioned effects.

[0026] The first binding molecule 310 can be suitably a molecule having a functional group capable of bonding to the first binding molecule 210 and a functional group capable of bonding to one end of the chain polymer 200 before bonding. The second binding molecule 320 can be suitably a molecule having a functional group capable of bonding to the second binding molecule 220 and a functional group capable of bonding to the other end of the chain polymer 200 before bonding. Examples of functional groups capable of bonding to the first binding molecule 210 and the second binding molecule 220 include silanol groups. Examples of functional groups capable of bonding to the end of the chain polymer 200 include acryloxy groups, methacryloxy groups, and vinyl groups.

[0027] Examples of the first binding molecule 310 and the second binding molecule 320 include acryloxypropyltrialkoxysilane, methacryloxypropyltrialkoxysilane, aminoalkyltrialkoxysilane, trialkoxysilylalkylisocyanate, and mercaptoalkyltrialkoxysilane. These can be used alone or in combination of two or more. The first binding molecule 310 and the second binding molecule 320 can be the same or different.

[0028] When the bonding layer 2 has the first bonding layer 31, the bonding layer 2 has an inner bonding portion 31 formed by a reaction between a functional group that one end of the chain polymer 200 had before bonding and a functional group that the first bonding molecule 310 had before bonding. i The bonding layer 2 also includes outer bonding portions 31 formed by a reaction between a functional group that the first bonding molecule 310 had before bonding and a functional group that the first bonding molecule 210 had before bonding. o Similarly, when the bonding layer 2 has the second bonding layer 32, the bonding layer 2 has an inner bonding portion 32 formed by a reaction between a functional group that the other end of the chain polymer 200 had before bonding and a functional group that the second bonding molecule 320 had before bonding. i The bonding layer 2 also includes outer bonding portions 32 formed by a reaction between a functional group that the second bonding molecule 320 had before bonding and a functional group that the second bonding molecule 220 had before bonding. o can have:

[0029] Although not shown, when the bonding layer 2 does not have the first bonding layer 31, the bonding layer 2 can include a bonding portion formed by a reaction between a functional group that was present at one end of the chain polymer 200 before bonding and a functional group that was present in the first bonding molecule 210 before bonding. Similarly, when the bonding layer 2 does not have the second bonding layer 32, the bonding layer 2 can include a bonding portion formed by a reaction between a functional group that was present at the other end of the chain polymer 200 before bonding and a functional group that was present in the second bonding molecule 220 before bonding.

[0030] Examples of combinations of the terminal functional group of the chain polymer 200, the functional group of the first binding molecule 310 (functional group of the first binding molecule 210) that reacts with the terminal functional group, and the functional group of the second binding molecule 320 (functional group of the second binding molecule 220) that reacts with the terminal functional group include combinations of vinyl group, acyl group and acryloxy group, silyl group and acryloxy group, carboxy group and amino group, carboxy group and isocyanate group, epoxy group and isocyanate group, epoxy group and amino group, epoxy group and thiol group, epoxy group and silanol group or hydroxy group, ethoxysilyl group and silanol group or hydroxy group, silanol group and silanol group or hydroxy group, etc. The combinations at one terminal side of the chain polymer 200 and the other terminal side of the chain polymer 200 may be the same or different.

[0031] The bonding layer 2 preferably has anisotropy of thermal expansion in the stacking direction Z. With this configuration, the bonding layer 2 thermally expands and contracts in the stacking direction Z (bonding direction) depending on the thermal history, but is less likely to thermally expand and contract in the direction X perpendicular to the stacking direction Z. Therefore, with this configuration, the bonding layer 2 is less likely to protrude in the direction X perpendicular to the stacking direction Z (is less likely to creep in the direction X perpendicular to the stacking direction Z). Note that, as illustrated in FIG. 1 , when the first bonding surface 110 and the second bonding surface 120 are flat surfaces, the stacking direction Z coincides with the normal direction of the first bonding surface 110 and the second bonding surface 120.

[0032] The bonding layer 2 having anisotropy of thermal expansion in the stacking direction Z means that the linear expansion coefficient of the bonding layer 2 in the stacking direction Z is greater than the linear expansion coefficient of the bonding layer 2 in the direction X perpendicular to the stacking direction Z. These linear expansion coefficients can be measured by thermomechanical analysis (TMA). The linear expansion coefficient of the bonding layer 2 in the stacking direction Z is measured at 150°C. The bonding layer 2 having anisotropy of thermal expansion in the stacking direction can be realized by bonding one end of the chain polymer 200 to the first bonding molecule 210 with or without the first bonding molecule 310, and bonding the other end of the chain polymer 200 to the second bonding molecule 220 with or without the second bonding molecule 320.

[0033] The bonding layer 2 can be configured such that the anisotropy ratio of thermal expansion, expressed as (linear expansion coefficient of the bonding layer 2 in the stacking direction Z) / (linear expansion coefficient of the bonding layer 2 in a direction perpendicular to the stacking direction Z), is 3 or more. With this configuration, the anisotropy of thermal expansion of the bonding layer 2 in the stacking direction Z is ensured, and the above-mentioned effects can be ensured.

[0034] The thickness of the bonding layer 2 can be 100 μm or less. In conventional technology, when the bonding layer is thin, it is difficult to improve the interfacial bonding even if a viscous material or a stress relaxation agent is used to reduce the elasticity of the bonding layer to prevent peeling. In contrast, when the thickness of the bonding layer 2 is 100 μm or less, the effects of the present disclosure can be fully achieved. The thickness of the bonding layer 2 can be measured by subtracting the thicknesses of the first and second bonded members 11 and 12 from the overall thickness of the bonded structure 1. The thickness of the bonding layer 2 is the arithmetic average of the thickness measurements of the bonding layer 2 at 10 locations.

[0035] The thickness of the bonding layer 2 can be preferably 80 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less, from the viewpoints of improving the thermal properties of the bonded structure 1 and reducing the size of the bonded structure 1. The thickness of the bonding layer 2 can be preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more, from the viewpoints of ensuring good stress relaxation properties and making it easier to ensure conformability to surface irregularities of the bonding surface.

[0036] The area of the bonding layer 2 is 400 mm 2 In the prior art, when the area of the bonding layer is large, it has been difficult to improve the interfacial bonding even if a viscous material or a stress relaxation agent is used to reduce the elasticity of the bonding layer to prevent peeling. In contrast, the above configuration allows the effects of the present disclosure to be fully exerted.

[0037] The area of the bonding layer 2 is preferably 60,000 mm from the viewpoint of reducing restrictions on the mounting space of the bonded structure 1. 2 Less than or equal to 15,000 mm, more preferably 2 Less than 5000 mm, more preferably 2 In addition, the area of the bonding layer 2 is preferably 600 mm or less from the viewpoint of improving the thermal properties and packaging properties required for the bonded structure 1. 2 More preferably, 900 mm 2 More preferably, 3000 mm 2 It can be more than that.

[0038] The Young's modulus of the bonding layer 2 can be 1 MPa or less. This configuration makes it easier to suppress warping and interfacial peeling of the bonding layer 2 by suppressing hardening of the bonding layer 2. Furthermore, from the viewpoint of improving the bonding position accuracy by suppressing misalignment between the first bonded member 11 and the second bonded member, the Young's modulus of the bonding layer 2 can be preferably 0.005 MPa or more, more preferably 0.05 MPa or more, and even more preferably 0.1 MPa or more. A method for measuring the Young's modulus of the bonding layer 2 will be described in detail in the experimental examples.

[0039] The elongation of the bonding layer 2 is preferably 1 μm / μm or more, and more preferably more than 1 μm / μm. With this configuration, the bonding strength of the bonding layer 2 can be increased even when the bonding area is relatively large. Furthermore, from the viewpoint of improving the handleability of the bonded structure 1, including the thermal properties and bonding position accuracy required of the bonded structure 1, the elongation of the bonding layer 2 can be preferably 100 μm / μm or less, more preferably 60 μm / μm or less, and even more preferably 30 μm / μm or less. The method for measuring the elongation of the bonding layer 2 will be described in detail in the experimental examples.

[0040] The bonded structure 1 can be manufactured, for example, as follows, but is not limited to this. First bonding molecules 210 are bonded to the surface of the first bonding surface 110 of the first member to be bonded 11 to form a first bonding molecule layer 21. Next, first bonding molecules 310 are bonded to the first bonding molecules 210 of the first bonding molecule layer 21 to form a first bonding layer 31. Furthermore, second bonding molecules 220 are bonded to the surface of the second bonding surface 120 of the second member to be bonded 12 to form a second bonding molecule layer 22. Next, second bonding molecules 320 are bonded to the second bonding molecules 220 of the second bonding molecule layer 22 to form a second bonding layer 32.

[0041] Next, a solution containing chain polymer 200, a crosslinking agent, and a diluent solvent is applied to at least one of the surfaces of first bonding layer 31 and second bonding layer 32, and the solvent is volatilized. Next, first bonding surface 110 and second bonding surface 120 are bonded together face-to-face and thermocompression bonded. This bonds one end of chain polymer 200 to first bonding molecule 310 and the other end of chain polymer 200 to second bonding molecule, forming bonding layer 2. This completes the manufacturing of the bonded structure 1 of this embodiment. Details will be explained in more detail in Embodiment 2. Note that if first bonding molecule 210 and one end of chain polymer 200, and second bonding molecule 220 and the other end of chain polymer 200 are directly bonded, the steps of forming first bonding layer 31 and second bonding layer 32 can be omitted.

[0042] In the method for manufacturing the bonded structure 1, the chain polymer 200 can be preferentially bonded to the first binding molecule 310 (second binding molecule 320) by selecting each functional group so that the reaction rate between the functional group at the end of the chain polymer 200 and the functional group of the first binding molecule 310 (second binding molecule 320) is faster than the reaction rate between the functional groups at the end of the chain polymer 200. The same applies to the case where the functional group at the end of the chain polymer 200 is preferentially bonded to the first binding molecule 210 (second binding molecule 220) without using the first binding molecule 310 (second binding molecule 320).

[0043] The reaction rate can be calculated from the rate and concentration of various functional groups before the reaction, the general crosslinking temperature, the activation energy during various reactions, etc. Specifically, for example, when functional group a reacts with functional group b to form functional group ab, the reaction rate k is expressed by the Arrhenius equation as k = Aexp(Ea / RT). A is the frequency factor. Ea is the activation energy when functional group a reacts with functional group b to form functional group ab. R is the gas constant. T is the absolute temperature. The frequency factor is A ∝ va[a]vb[b]. va is the rate of functional group a, [a] is the concentration of functional group a, vb is the rate of functional group b, and [b] is the concentration of functional group b.

[0044] The bonded structure 1 of this embodiment can be applied to various fields requiring the reduction of stress applied to the bonding layer 2 and the prevention of interfacial delamination of the bonding layer 2. In particular, the bonded structure 1 can be suitably used in semiconductor devices, electric devices, and the like. Semiconductor devices and electric devices including power semiconductors and the like are increasingly being used in vehicles such as automobiles. Semiconductor devices and electric devices require ensuring electrical conductivity and insulation to form circuits. Furthermore, because high voltages and large currents cause localized heat generation in elements, it is necessary to ensure a heat dissipation path from the elements to the outside of the device. Therefore, semiconductor devices and electric devices often use a ceramic material to achieve insulating properties and a metal material to achieve electrical and heat transfer properties. Furthermore, resin materials such as liquid crystal polymers and epoxy resins may be bonded to control the dielectric properties around the elements or for sealing purposes. Conventional bonded structures, which bond different types of bonded members with significantly different linear expansion coefficients (e.g., metal and ceramic materials, metal and resin materials, or ceramic and resin materials), are prone to interfacial delamination of the bonding layer due to their inability to withstand deformation caused by thermal expansion and contraction due to applied thermal history. This problem becomes more pronounced as the joining area becomes larger and the joining layer becomes thinner. 2As described above, when the thickness of the bonding layer is 100 μm or less, it is difficult to improve the interfacial bondability even if the elasticity of the bonding layer is reduced using a viscous material or a stress relaxation agent to prevent peeling. Furthermore, conventional bonded structures, in which an adhesive material is sandwiched between the bonded members and cured, can reduce the thickness of the bonding layer, but the adhesive components aggregate or react with each other, resulting in poor interfacial bondability of the bonding layer. The larger the bonded area, the more likely interfacial peeling of the bonding layer is. In contrast, the bonded structure 1 of this embodiment can suppress interfacial peeling of the bonding layer 2 by improving the interfacial bondability of the bonding layer 2. Furthermore, the configuration of the bonding layer 2 in the bonded structure 1 of this embodiment allows for anisotropy of thermal expansion in the stacking direction Z. Therefore, the bonded structure 1 of this embodiment is less likely to extrude in the direction X perpendicular to the stacking direction Z due to applied thermal history, thereby improving the creep resistance of the bonding layer 2. Therefore, the bonded structure 1 of this embodiment can be used effectively in semiconductor devices, electric devices, and the like. Specific examples of the first member to be joined 11 and the second member to be joined 12 include a circuit board and a heat dissipation member.

[0045] (Embodiment 2) The joined structure of the second embodiment will be described with reference to Fig. 2 to Fig. 9. Of the symbols used in the second and subsequent embodiments, the same symbols as those used in the previous embodiments represent the same components as those in the previous embodiments, unless otherwise specified.

[0046] As illustrated in FIG. 2 , in the bonded structure 1 of this embodiment, the material of the first bonded member 11 is a metal material, specifically copper or a copper alloy. The material of the second bonded member 12 is a ceramic material, specifically silicon nitride. The chain polymer 200 is derived from a silicone polymer having a silicone chain as the main chain and vinyl groups at both ends. The first bonding molecule 210 and the second bonding molecule 220 are both molecules having a triazine ring, an amino group, and a silanol group, specifically derived from N,N′-bis(2-aminoethyl)-6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine. The first bonding molecule 310 and the second bonding molecule 320 are both molecules having a silanol group and an acryloxy group, specifically derived from acryloxypropyltrialkoxysilane.

[0047] 2, in the bonded structure 1 of this embodiment, the first bonding molecules 210 are bonded to the surface of the first bonding surface 110 of the first bonded member 11 via amino groups. The silanol groups of the first bonding molecules 210 and the silanol groups of the first bonding molecules 310 bond to each other, forming outer bonding portions 31. o The acryloxy group of the first binding molecule 310 is bonded to the vinyl group at one end of the chain polymer 200, forming an inner binding portion 31. i Similarly, in the bonded structure 1 of this embodiment, the second bonding molecules 220 are bonded to the surface of the second bonding surface 120 of the second bonded member 12 via silanol groups. The silanol groups of the second bonding molecules 220 and the silanol groups of the second bonding molecules 320 bond to each other, forming outer bonding portions 32. o The acryloxy group of the second binding molecule 320 is bonded to the vinyl group at the other end of the chain polymer 200, forming an inner binding portion 32. i is formed.

[0048] The bonded structure 1 of this embodiment can be manufactured, for example, as follows. The first bonding surface 110, which is made of copper or a copper alloy, is degreased and then pickled to remove any oxide film. Next, a solution containing first bonding molecules 210 is brought into contact with the first bonding surface 110, and the solution is then dried. As a result, as shown in FIG. 3(a), the first bonding molecules 210 are bonded to the surface of the first bonding surface 110 of the first bonded member 11 via the amino groups, forming a first bonding molecule layer 21. Next, as shown in FIG. 3(a), a solution containing first bonding molecules 310 is brought into contact with the surface of the first bonding molecule layer 21, and the solution is then dried. As a result, as shown in FIG. 3(b), the silanol groups of the first bonding molecules 210 and the silanol groups of the first bonding molecules 310 are bonded to form a first bonding layer 31.

[0049] The second bonding surface 120, made of silicon nitride, is degreased, then subjected to corona plasma treatment and alkali treatment, washed with water, and dried to form an active layer 211 on the surface of the second bonding surface 120. Next, as shown in FIG. 4(a), a solution containing second bonding molecules 220 is contacted with the second bonding surface 120 on which the active layer 211 has been formed, and the solution is then dried. As a result, as shown in FIG. 4(b), the second bonding molecules 220 are bonded to the surface of the second bonding surface 120 of the second member 12 via silanol groups, forming a second bonding molecule layer 22. Next, as shown in FIG. 5(a), a solution containing second bonding molecules 320 is contacted with the surface of the second bonding molecule layer 22, and the solution is then dried. As a result, as shown in FIG. 5(b), the silanol groups of the second bonding molecules 220 and the second bonding molecules 320 are bonded to each other, forming a second bonding layer 32.

[0050] Next, as shown in FIG. 6(c), a solution is prepared containing a chain polymer 200 having a silicone main chain and vinyl groups at both ends, a crosslinker such as dicumyl peroxide, and a dilution solvent. Next, as shown in FIGS. 6(a) and 7(a), this solution is applied to at least one of the surfaces of the first bonding layer 31 and the second bonding layer 32, and the solvent is evaporated. Next, the first bonding surface 110 and the second bonding surface 120 are bonded together, facing each other. Next, thermocompression bonding is performed. Thermocompression bonding can be performed, for example, in air at a temperature of 190°C, with a bonding force of 0.1 MPa, and for a bonding time of 45 minutes. As a result, as shown in Figures 6(b) and 7(b), the vinyl group at one end of the chain polymer 200 is bonded to the acryloxy group of the first binding molecule 310, and the vinyl group at the other end of the chain polymer 200 is bonded to the acryloxy group of the second binding molecule 320, thereby forming the bonding layer 2.

[0051] In this manner, the joined structure 1 of this embodiment as shown in FIG. 2 can be manufactured.

[0052] In the bonded structure 1 of this embodiment, the first bonded member 11 is made of copper or a copper alloy, which is advantageous in ensuring electrical conductivity and thermal conductivity. Furthermore, the second bonded member 12 is made of silicon nitride, which is advantageous in ensuring strength and insulation. Furthermore, the bonded structure 1 of this embodiment uses molecules having a triazine ring, such as N,N'-bis(2-aminoethyl)-6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine, as the first bonding molecules 210 and the second bonding molecules 220. This allows for high-density adsorption to the first bonding surface 110 and the second bonding surface 120, which is advantageous in improving interfacial bonding between the first bonding surface 110 and the second bonding surface 120. Furthermore, in the bonded structure 1 of this embodiment, the main chain constituting the chain polymer 200 is a silicone chain. This allows the silicone chain to assume a folded or unfolded form, enhancing the stress relaxation effect due to the expansion and contraction of the silicone chain. Furthermore, the bonded structure 1 of this embodiment uses the chain polymer 200 whose terminal functional group is a vinyl group, and therefore has excellent reactivity with an acryloxy group.

[0053] Furthermore, the bonded structure 1 of this embodiment uses molecules having an acryloxy group and a silanol group, such as acryloxypropyltrialkoxysilane, as the first bonding molecules 310 and the second bonding molecules 320. The reaction rate between the acryloxy groups of the first bonding molecules 310 and the second bonding molecules 320 and the vinyl groups at the ends of the chain polymers 200 is faster than the reaction rate between the vinyl groups at the ends of the chain polymers 200. Therefore, during the production of the bonded structure 1, adjacent chain polymers 200 are less likely to polymerize with each other via the terminal vinyl groups, and the acryloxy groups of the first bonding molecules 310 and the second bonding molecules 320 can preferentially react with the vinyl groups at the ends of the chain polymers 200. Therefore, the bonded structure 1 of this embodiment ensures reliable bonding between one end of the chain polymer 200 and the first bonding molecule 310 and between the other end of the chain polymer 200 and the second bonding molecule 320.

[0054] According to this embodiment, a joint structure 1 having a high stress relaxation effect and high joint strength can be obtained. The other configurations and effects are the same as those of the first embodiment.

[0055] (Embodiment 3) A bonded structure of embodiment 3 will be described with reference to FIG. 8. As illustrated in FIG. 8, in the bonded structure 1 of this embodiment, the material of the first bonded member 11 is a resin material, specifically, a liquid crystal polymer (LCP). The bonded structure 1 of this embodiment is an example in which a liquid crystal polymer and silicon nitride, which have significantly different linear expansion coefficients, are combined. FIG. 8 corresponds to FIG. 3(a) described in the bonded structure of embodiment 2. In FIG. 8, first bonding molecules 210 are bonded to the first bonding surface 110 of the first bonded member 11 made of LCP, and first bonding molecules 310 (not shown) are bonded to this in the same manner as in embodiment 2. The other configurations are the same as those of embodiment 2.

[0056] This embodiment also provides a joint structure 1 with a high stress relaxation effect and high joint strength. Other effects are the same as those of the second embodiment.

[0057] (Embodiment 4) A bonded structure of embodiment 4 will be described with reference to FIG. 9. As illustrated in FIG. 9, in the bonded structure 1 of this embodiment, the material of the second member to be bonded 12 is a resin material, specifically, epoxy resin. The bonded structure 1 of this embodiment is an example in which copper or a copper alloy and epoxy resin, which have relatively similar linear expansion coefficients, are combined. FIG. 9 corresponds to FIG. 4(b) described in the bonded structure of embodiment 2. In FIG. 9, second bonding molecules 220 are bonded to the second bonding surface 120 of the second member to be bonded 12, which is made of epoxy resin, and second bonding molecules 320 (not shown) are bonded to this, as in embodiment 2. The other configurations are the same as those of embodiment 2.

[0058] This embodiment also provides a joint structure 1 with a high stress relaxation effect and high joint strength. Other effects are the same as those of the second embodiment.

[0059] (Experimental Example 1) <Preparation of test specimen> -Test specimen 1- The following materials were prepared for use in producing specimen 1. ·First member to be joined A copper plate (manufactured by Nilaco Corporation, "CU-113421") measuring 10 mm x 40 mm and having a thickness of 0.3 mm was prepared. ·Second member to be joined A silicon nitride plate (Toshiba Materials Co., Ltd., "SiN White Plate TSN-90") measuring 10 mm x 40 mm and having a thickness of 0.32 mm was prepared. ·Chain polymer A silicone polymer (Gelest, "DSM-V31") having a linear silicone main chain and vinyl groups at both ends was prepared. The molecular weight of this linear polymer was 30,000. ·Joint molecules N,N'-bis(2-aminoethyl)-6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine (manufactured by Io Chemical Research Institute, "MB-1015") was prepared. ·Binding molecules Acryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM-5103") was prepared.

[0060] A copper plate was immersed in acetone at a temperature of 25°C and degreased by ultrasonic treatment at a frequency of 40 kHz for 3 minutes, then removed, rinsed with acetone, and dried in a dryer for 30 seconds at a temperature of 60°C. The degreased copper plate was then immersed in a 0.2% aqueous solution of hydrochloric acid at a temperature of 25°C for 10 seconds to remove the oxide film on the surface, followed by rinsing with water and drying in a dryer in the same manner as above.

[0061] In addition, silicon nitride plates were degreased by immersion in acetone at 25°C and ultrasonic treatment at a frequency of 40 kHz for 10 seconds. The plates were then removed, rinsed with acetone, and dried in a dryer as described above. The degreased silicon nitride plates were then activated by corona plasma treatment at an applied voltage of 12.5 kV, six strokes, and a sweep speed of 30 mm / s. Corona plasma treatment was performed using a Shinko Electric Instruments Corona Master. The corona plasma-treated silicon nitride plates were then immersed in a 50 g / L aqueous solution of sodium silicate at 60°C, rinsed with water, and dried in a dryer as described above.

[0062] Next, one side of the copper plate, from which the oxide film had been removed, was immersed in a 1% solution of bonding molecules for 300 seconds, and then dried in a dryer as described above. The surface of the copper plate treated with bonding molecules was then immersed in a 1% solution of bonding molecules for 300 seconds, and then air-dried for 3 minutes. Similarly, one side of a silicon nitride plate that had been corona-plasma-treated and alkali-treated was immersed in a 1% solution of bonding molecules for 300 seconds, and then air-dried as described above. The surface of the silicon nitride plate treated with bonding molecules was then immersed in a 1% solution of bonding molecules for 300 seconds, and then air-dried for 20 minutes. Note that this experimental example uses bonding molecules.

[0063] Next, a hexane solution containing the chain polymer and dicumyl peroxide was applied dropwise to the bonding surfaces of the copper plate and the silicon nitride plate, which had been pretreated as described above, to a predetermined thickness, and then allowed to dry naturally for 10 minutes to volatilize the hexane. The dicumyl peroxide was used in an amount of 3 parts by mass per 100 parts by mass of the chain polymer. The bonding surfaces were then bonded together and thermocompressed in air at 190°C, with a pressure of 0.1 MPa and a bonding time of 45 minutes. A PA System screw heater press was used for thermocompression bonding. Specimen 1 was obtained.

[0064] -Test specimen 1C- Specimen 1C was obtained in the same manner as in the preparation of specimen 1, except that neither the joining molecule treatment nor the bonding molecule treatment was performed on the surfaces of the copper plate and the silicon nitride plate.

[0065] -Test specimen 2C- Specimen 2C was obtained in the same manner as in the preparation of Specimen 1, except that vinyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM-1003") was used as the binding molecule.

[0066] -Test specimen 3C- Specimen 3C was obtained in the same manner as in the preparation of specimen 1, except that a silicone polymer having a vinyl group in the side chain (manufactured by Gelest, "VDT-131") was used instead of the chain polymer.

[0067] -Test specimen 2- As the first member to be joined, an LCP plate (manufactured by Kuraray Co., Ltd., "CT-Z") measuring 10 mm x 40 mm and having a thickness of 50 μm was prepared. The LCP plate was then immersed in acetone at 25°C and ultrasonically degreased at 40 kHz for 3 minutes. The copper plate was then removed, rinsed with acetone, and dried in a dryer at 60°C for 30 seconds. The degreased LCP plate's surface was then activated by corona plasma treatment at an applied voltage of 12.5 kV, 3 strokes, and a sweep speed of 30 mm / s. One side of the corona plasma-treated LCP plate was then immersed in a 1% solution of bonding molecules for 300 seconds and then dried in a dryer as described above. The surface of the bonding molecule-treated LCP plate was then immersed in a 1% solution of bonding molecules for 300 seconds and then air-dried for 20 minutes.

[0068] Thereafter, specimen 2 was obtained in the same manner as specimen 1, except that the pretreated copper plate was replaced with the LCP plate that had been pretreated as described above.

[0069] -Test specimen 3- Specimen 3 was obtained in the same manner as in producing specimen 2, except that 20 vol % of an inorganic filler was added to the hexane solution containing the chain polymer and dicumyl peroxide.

[0070] -Test specimen 4C- Specimen 4C was obtained in the same manner as in producing specimen 2, except that neither the joining molecule treatment nor the bonding molecule treatment was performed on the surfaces of the LCP plate and the silicon nitride plate.

[0071] -Test specimen 5C- Specimen 5C was obtained in the same manner as in producing specimen 3, except that neither the joining molecule treatment nor the bonding molecule treatment was performed on the surfaces of the LCP plate and the silicon nitride plate.

[0072] <Shear joint strength evaluation> Tensile shear strength tests were performed on the bonded structures of each specimen using a benchtop precision universal testing machine (Shimadzu Corporation, Autograph AGS-X). Specifically, the tensile shear bond strength of the bonded layer was determined from the applied tensile force when the strength suddenly dropped due to fracture of the specimen. The shear displacement (μm) was defined as the displacement from the onset of displacement of the bonded layer to fracture, and this was divided by the thickness (μm) of the bonded layer at 25°C to determine the elongation (μm / μm) of the bonded layer. The Young's modulus of the bonded layer was calculated from the relationship curve between the tensile shear bond strength and shear displacement and the thickness of the bonded layer. Specifically, the Young's modulus of the bonded layer was calculated using the average slope from the onset of displacement, where shear strength is developed, to the tensile strength developed at 0.05 mm of displacement and the thickness of the bonded layer: modulus of rigidity = average slope × thickness of the bonded layer; Young's modulus = modulus of rigidity × 2 × (1 + Poisson's ratio of the bonded layer). The shear displacement for specimens 2, 3, 4C, and 5C was measured from the start of displacement until the tensile strength reached 0.1 MPa. This is because the LCP plate also stretches when tensile force is applied, so the shear displacement was measured at a displacement up to the tensile force range where the LCP plate can be approximated as a rigid body.

[0073] In addition, the fracture surface morphology of the test specimens after the tensile shear strength test was visually observed. If a fracture surface was observed in which the bonding layer was present across the entire bonding surface of both the first and second bonded members, it was determined to be a bonding layer failure. If a fracture surface was observed in which the bonding layer was absent on the bonding surface of at least one of the first and second bonded members, it was determined to be an interfacial failure.

[0074] Table 1 summarizes the details and evaluation results of test specimens 1, 1C, 2C, and 3C. Figure 10 shows graphs of the tensile shear strength and shear displacement of test specimens 1, 1C, 2C, and 3C. Table 2 also summarizes the details and evaluation results of test specimens 2, 3, 4C, and 5C. Figure 11 shows graphs of the tensile shear bond strength and shear displacement of test specimens 2, 3, 4C, and 5C. Note that the shear displacement in Figure 11 is the shear displacement from the start of displacement to a tensile load of 0.1 MPa.

[0075] [Table 1]

[0076] [Table 2]

[0077] Tables 1, 2, Figures 10, and 11 reveal the following. Specimens 1C, 4C, and 5C did not have a bonding molecule layer or a binding molecule layer, so the fracture surface morphology was interfacial. Specimen 2C also had interfacial fracture. This is thought to be because the reaction rate between the terminal vinyl groups of the chain polymers was faster than the reaction rate between the terminal vinyl groups of the chain polymers and the vinyl groups of the binding molecules, preventing the ends of the chain polymers from preferentially bonding to the binding molecules. Specimen 3C also had a bonding layer fracture, but the shear displacement of the bonding layer was small, resulting in poor stretchability and poor stress relaxation. This is thought to be due to the large number of bonds formed between the side-chain vinyl groups of the silicone polymer used to form the stress relaxation layer.

[0078] In contrast, specimens 1, 2, and 3 all exhibited fracture surface morphology of bond layer failure, high tensile shear bond strength, and suppressed interfacial delamination between the bonded components and the bond layer. Furthermore, because bond layer delamination was suppressed in specimens 1, 2, and 3, the stress relaxation properties of the stress relaxation layer were fully demonstrated. Furthermore, specimens 1, 2, and 3 exhibited large shear displacement in the bond layer, demonstrating good elasticity, and therefore superior stress relaxation properties. This is thought to be due to the terminal vinyl groups of the chain polymer preferentially binding to the bonding molecules, suppressing polymerization between adjacent chain polymers near the interface of the bonded components.

[0079] (Experimental Example 2) <Preparation of test specimen>

[0080] -Test specimen 4- Specimen 4 was prepared in the same manner as Specimen 1 in Experimental Example 1, except that the copper plate had dimensions of 25 mm x 25 mm and a thickness of 3 mm, and the silicon nitride plate had dimensions of 25 mm x 25 mm and a thickness of 0.32 mm.

[0081] -Test specimen 5- Specimen 5 was obtained in the same manner as specimen 4, except that 40 vol % of an inorganic filler was added to the hexane solution containing the chain polymer and dicumyl peroxide.

[0082] -Test specimen 6C- Specimen 6C was obtained in the same manner as specimen 4, except that 40 vol% of inorganic filler was added to a hexane solution containing a chain polymer and dicumyl peroxide, and neither the joining molecule treatment nor the bonding molecule treatment was performed on the surfaces of the copper plate and the silicon nitride plate.

[0083] <Shear joint strength evaluation> For specimen 5 and specimen 6C, the tensile shear bonding strength was evaluated in the same manner as in Experimental Example 1. However, the sizes of the copper plate and silicon nitride were the same as those in Experimental Example 1.

[0084] <Thermal cycle durability evaluation> Each specimen was subjected to a thermal cycle durability evaluation. Specifically, each specimen was subjected to a thermal cycle, and the presence or absence of peeling of the bonding layer was confirmed using an ultrasonic imaging system (SAT). The thermal cycle was performed by immersing the specimen in Galden in a liquid phase thermal cycle, with one cycle consisting of room temperature → 150°C for 5 minutes → room temperature for 30 seconds → -40°C for 5 minutes → room temperature for 30 seconds. In this experimental example, 5,000 thermal cycles were applied. The ultrasonic imaging system used was a C-SAM Gen6 manufactured by Sonoscan, with a 50 MHz transducer.

[0085] In the images taken with the ultrasound imaging device, the white areas seen in contrast were defined as areas where the bonding layer had peeled, and the dark gray areas were defined as areas where the bonding layer had not peeled.If the area of the white areas expanded by 5% or more by 5000 cycles, it was determined that interfacial peeling of the bonding layer had occurred due to the thermal cycle.If the area of the white areas expanded by less than 5% by 5000 cycles, it was determined that interfacial peeling of the bonding layer had not occurred due to the thermal cycle.

[0086] Table 3 shows the details and evaluation results of specimens 4, 5, and 6C.

[0087] [Table 3]

[0088] Table 3 reveals the following: Specimen 6C did not have a bonding molecular layer or a binding molecular layer, and therefore the fracture surface morphology was interfacial failure, and interfacial peeling of the bonding layer occurred due to the thermal cycle.

[0089] In contrast, for specimens 4 and 5, regardless of whether the stress relaxation layer contained inorganic filler, the fracture surface morphology was fracture of the bonding layer, and no interfacial peeling of the bonding layer occurred due to the thermal cycle. This result confirmed that the configuration of the present disclosure can provide a bonded structure that is highly resistant to thermal cycles, can relieve thermal stress, and can ensure high bonding strength, even when bonding dissimilar materials with different linear expansion coefficients.

[0090] (Experimental Example 3) <Preparation of test specimen> -Sample 6- The following materials were prepared as materials used to fabricate the specimen 6. ·First member to be joined A copper plate (manufactured by Nilaco Corporation, "CU-113421") measuring 10 mm x 40 mm and having a thickness of 0.3 mm was prepared. ·Chain polymer A silicone polymer (Gelest, "DSM-V31") having a linear silicone main chain and vinyl groups at both ends was prepared. The molecular weight of this linear polymer was 30,000. ·Joint molecules N,N'-bis(2-aminoethyl)-6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-diamine (manufactured by Io Chemical Research Institute, "MB-1015") was prepared. ·Binding molecules Acryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM-5103") was prepared.

[0091] In the same manner as in Specimen 1 of Experimental Example 1, the bonding surfaces of the copper plates were pretreated to bond bonding molecules to the bonding surfaces of the copper plates, and further bonding molecules were bonded to the bonding molecules.

[0092] Next, a liquid containing a chain polymer and dicumyl peroxide was prepared. The dicumyl peroxide was used in an amount of 3 parts by mass per 100 parts by mass of the chain polymer. A cured silicone mold was then prepared so that the chain polymer would contact the bonding surface of the pretreated copper plate and would not flow in the planar direction. The liquid containing the chain polymer and dicumyl peroxide was poured into this mold. The chain polymer was then cured in air at 190°C, 0.1 MPa, and 45 minutes. This yielded specimen 6.

[0093] -Test specimen 7- A silicone polymer (Gelest, "EM2-EX-100A") was prepared, which had a linear silicone backbone, a silyl group at one end, and a vinyl group at the other end. This chain polymer had a molecular weight of 100,000 and contained 30 vol% of inorganic filler. A liquid containing this chain polymer and a platinum catalyst was prepared. The platinum catalyst was used in an amount of 0.5 parts by mass per 100 parts by mass of the chain polymer.

[0094] Specimen 7 was obtained in the same manner as in producing specimen 6, except that a liquid containing the chain polymer and platinum catalyst was poured into the mold.

[0095] -Test specimen 7C- Specimen 7C was obtained in the same manner as in producing specimen 6, except that neither the joining molecule treatment nor the binding molecule treatment was performed on the surface of the copper plate.

[0096] -Test specimen 8C- Specimen 8C was obtained in the same manner as in producing specimen 7, except that neither the joining molecule treatment nor the binding molecule treatment was performed on the surface of the copper plate.

[0097] -Test specimen 9C- Specimen 9C was obtained in the same manner as in the preparation of specimen 6, except that only the bonding molecule treatment was performed on the surface of the copper plate, and no binding molecule treatment was performed.

[0098] -Test specimen 10C- Specimen 10C was obtained in the same manner as in the preparation of specimen 7, except that only the bonding molecule treatment was performed on the surface of the copper plate, and no binding molecule treatment was performed.

[0099] <Evaluation of interfacial bonding properties of bonding layer against solvents> Each test piece was immersed in hexane for 24 hours, and then removed. Immediately after removal, the state of interfacial peeling of the bonding layer was checked. Immediately after removal, the bonding layer was swelled and the bonding layer had already peeled at the interface, and those that did not peel at the interface but would break if peeled by hand.

[0100] Table 4 shows the details and evaluation results of specimens 6, 7, and 7C to 10C.

[0101] [Table 4]

[0102] Table 4 reveals the following. Specimens 7C and 8C did not have a bonding molecule layer or a binding molecule layer, and therefore exhibited poor interfacial adhesion of the bonding layer to solvents. Furthermore, specimens 9C and 10C, which only had a bonding molecule layer, also exhibited poor interfacial adhesion of the bonding layer to solvents. The following reasons are believed to explain this: The terminal functional groups of the chain polymer bond preferentially with the functional groups of the binding molecules, providing the bonding density necessary to maintain interfacial adhesion. However, without the binding molecules, the bonding reaction with the interface was insufficient, resulting in insufficient bonding density and allowing the solvent to easily penetrate the interface. Furthermore, the silanol and amino groups of the bonding molecules do not generally react with vinyl or silyl groups. While amino groups exhibit adsorptive and adhesive properties, similar to hydrogen bonding, this is thought to be the cause of the solvent penetration into the interface, as described above.

[0103] In contrast, it was confirmed that the bonding layer of specimens 6 and 7 was resistant to interfacial peeling even when exposed to a solvent.

[0104] In this experimental example, a silicone-based chain polymer was used, and the interfacial bonding of the bonding layer was evaluated using the above method. If a different type of chain polymer is used, the bonding layer can be washed with a dissolving detergent, and the presence or absence of resin components and the bond reaction structure can be identified using known methods such as XPS analysis and FT-IR analysis of the bonding surfaces of the bonded members to evaluate and confirm the interfacial bonding.

[0105] (Experimental Example 4) <Preparation of test specimen>

[0106] -Test specimen 8- Specimen 8 was prepared in the same manner as Specimen 1 in Experimental Example 1, except that the copper plate had dimensions of 10 mm x 10 mm and a thickness of 0.3 mm, and the silicon nitride plate had dimensions of 10 mm x 10 mm and a thickness of 0.32 mm.

[0107] -Test specimen 11C- Specimen 11C was obtained in the same manner as in producing specimen 1 of Experimental Example 1, except that neither the joining molecule treatment nor the bonding molecule treatment was performed on the surfaces of the copper plate and the silicon nitride plate.

[0108] <Evaluation of thermal expansion anisotropy of bonding layer> For each bonded structure, the linear expansion of the bonded layer in the lamination direction due to temperature-dependent thickness changes was evaluated using thermomechanical analysis (TMA).

[0109] Specifically, the bonded structure of each test specimen was placed in a thermomechanical analyzer at room temperature, and the thickness change of the bonding layer in the stacking direction was measured under a nitrogen atmosphere using a temperature profile of room temperature → -10°C → 210°C → -10°C → 210°C. The heating rate was 10°C / min, and the cooling rate was -20°C / min. Note that TMA measurements of the bonded copper and silicon nitride plates, which were simply stacked together, and measurements of the overall thickness of the bonded structure were conducted in advance. Additionally, a specimen was prepared in which only the bonding layer was hardened, and similar TMA measurements were conducted in advance in the stacking direction and the direction perpendicular to the stacking direction.

[0110] The thickness of the bonding layer was calculated by subtracting the thickness of the bonded members from the total thickness of the bonded structure during the second temperature change from -10°C to 210°C in the temperature profile. The thickness of the bonding layer calculated at each temperature was divided by the thickness of the bonding layer at 25°C to obtain a normalized value, and the thickness ratio of the bonding layer was calculated when the thickness of the bonding layer at 25°C was set to 1. The linear expansion coefficient of the bonding layer in the stacking direction was calculated from the slope of the tangent at 150°C of the change in bonding layer thickness with temperature. The linear expansion coefficient of the bonding layer in the direction perpendicular to the stacking direction was calculated in the same manner as in the measurement of the linear expansion coefficient of the bonding layer in the stacking direction, by cutting the bonded structure parallel to the plane perpendicular to the stacking direction and using the cut-out amount in the direction perpendicular to the stacking direction as the thickness of the bonding layer in the direction perpendicular to the stacking direction.

[0111] Table 5 summarizes the details and evaluation results of specimen 8 and specimen 11C. Figure 12 shows the relationship between the temperature and the thickness ratio of the bonding layer for specimens 8 and 11C. Figure 13 shows the linear expansion coefficient in the lamination direction of the bonding layer for specimens 8 and 11C.

[0112] [Table 5]

[0113] Table 5, Figures 12, and 13 reveal the following: The bonding layer of specimen 11C exhibits a thermal expansion coefficient in the stacking direction that is approximately equal to the average of the thermal expansion coefficients of the silicone material in the stacking direction and the direction perpendicular to the stacking direction, depending on the thermal history. In contrast, specimen 8, despite using the same silicone material, exhibits a significantly larger linear expansion coefficient in the stacking direction of the bonding layer, exhibiting extreme expansion and contraction in the stacking direction depending on the thermal history. Furthermore, even with the same material composition, when the higher-order structure is controlled, such as by orientation or edge fixation as an interface boundary condition, due to the relationship between energy and entropy, when thermal expansion in one direction is large, thermal expansion in the other direction is generally small. From these results, it was confirmed that, according to the present disclosure, the bonding layer exhibits a large anisotropy of thermal expansion in the stacking direction.

[0114] The present invention is not limited to the above-described embodiments and experimental examples, and various modifications are possible without departing from the spirit of the present invention. Furthermore, the configurations shown in the embodiments and experimental examples can be combined in any manner. Below, examples of reference forms are given. Section 1. The bonding device includes a first bonded member (11) having a first bonding surface (110), a second bonded member (12) having a second bonding surface (120), and a bonding layer (2) that bonds the first bonding surface and the second bonding surface together, The bonding layer is a stress relief layer (20) containing a chain polymer (200); a first bonding molecule layer (21) including first bonding molecules (210) bonded to the first bonding surface; a second bonding molecule layer (22) including second bonding molecules (220) bonded to the second bonding surface, One end of the chain polymer is bound to the first binding molecule (310) with or without a first binding molecule (310); The other end of the chain polymer is bound to the second binding molecule (320) with or without a second binding molecule (320). Joint structure (1). Section 2. the bond between the first bonding molecule and the first bonding surface and the bond between the second bonding molecule and the second bonding surface are chemical bonds; Item 1. The bonded structure according to item 1. Section 3. The bonding layer has anisotropy of thermal expansion in the stacking direction (Z). Item 1 or 2. The bonded structure according to item 1 or 2. Section 4. The thickness of the bonding layer is 100 μm or less. Item 4. The bonded structure according to any one of items 1 to 3. Section 5. The chain polymer has a molecular weight of 5,000 or more and 150,000 or less. Item 5. The bonded structure according to any one of items 1 to 4. Section 6. The linear expansion coefficient of the first member to be joined and the linear expansion coefficient of the second member to be joined differ by one order of magnitude or more. Item 6. The bonded structure according to any one of items 1 to 5. [Explanation of symbols]

[0115] 1 Joined structure 11 First member to be joined 110 1st joint surface 12 Second member to be joined 120 Second joint surface 2 Bonding layer 20 Stress relief layer 200 Chain polymer 21 1st junction molecular layer 210 First junction molecule 310 1st binding molecule 22 Second junction molecular layer 220 Second junction molecule 320 Second binding molecule

Claims

1. The bonding apparatus includes a first bonded member (11) having a first bonding surface (110), a second bonded member (12) having a second bonding surface (120), and a bonding layer (2) that bonds the first bonding surface and the second bonding surface together, The bonding layer is a stress relief layer (20) containing a chain polymer (200); a first bonding molecule layer (21) including first bonding molecules (210) bonded to the first bonding surface; a second bonding molecule layer (22) including second bonding molecules (220) bonded to the second bonding surface; One end of the chain polymer is bound to the first binding molecule via a first binding molecule (310); the other end of the chain polymer is bound to the second binding molecule via a second binding molecule (320); The chain polymer is derived from a silicone polymer having a silicone chain as the main chain and vinyl groups at both ends, the first adhesive molecule and the second adhesive molecule are both molecules having a triazine ring, an amino group, and a silanol group, the first binding molecule and the second binding molecule are both molecules having a silanol group and an acryloxy group; Joined structure (1).

2. the bond between the first bonding molecule and the first bonding surface and the bond between the second bonding molecule and the second bonding surface are chemical bonds; The bonded structure according to claim 1 .

3. The bonding layer has anisotropy of thermal expansion in the stacking direction (Z). The bonded structure according to claim 1 or 2.

4. The thickness of the bonding layer is 100 μm or less. The bonded structure according to any one of claims 1 to 3.

5. The chain polymer has a molecular weight of 5,000 or more and 150,000 or less. The bonded structure according to any one of claims 1 to 4.

6. The linear expansion coefficient of the first member to be joined and the linear expansion coefficient of the second member to be joined differ by one order of magnitude or more. The bonded structure according to any one of claims 1 to 5.

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