Next, the structure

Abstract

To provide an adhesive structure that is less prone to degradation or deterioration due to heat, and also has high adhesive strength.SOLUTION: An adhesive structure has its surface composed, at least partially, of an inorganic material. The surface has an elastic modulus in the range of 0.01 GPa to 50 GPa. Using a nanoindenter to press a spherical indenter with a diameter of 40 μm into the surface at a pressing depth of either 10 nm or 20 nm, the adhesive force is 35 N / cm2 or higher.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an adhesive structure. [Background technology]

[0002] A known adhesive structure has a substrate and a plurality of protrusions provided on the surface of the substrate. Patent Document 1 discloses an adhesive structure with protrusions whose tips are spherical with a radius of 300 nm or less and whose cross section perpendicular to the longitudinal direction has a radius of 500 nm or less. It is said that this adhesive structure with nano-level protrusions can penetrate into the unevenness of the surface of the adherend at the nano-level, thereby exerting a strong adhesive force. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2007 / 032164 Summary of the Invention [Problem to be solved by the invention]

[0004] It is preferable that the bonded structure can stably bond and hold the adherend under various environments and is not likely to contaminate the adherend. However, the bonded structure described in Patent Document 1 is formed from a resin material. Resin materials may be decomposed or altered by heat, which may reduce the adhesive strength. Furthermore, the decomposition products of resin materials may contaminate the adherend. Furthermore, since resin materials generally have an elastic modulus of less than 0.1 MPa, they are easily deformed when pressed by the adherend, but are difficult to restore to their original shape when released from the pressure applied by the adherend. For this reason, bonded structures made from resin materials tend to have deformed protrusions after a single use, making repeated use difficult.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an adhesive structure that is resistant to decomposition or deterioration due to heat, has high adhesive strength, and can be used repeatedly. [Means for solving the problem]

[0006] In order to solve the above problems, the adhesive structure of the present invention has a surface at least partly made of an inorganic material, the surface made of the inorganic material having an elastic modulus in the range of 0.01 GPa to 50 GPa, and an adhesive strength of 35 N / cm when a spherical indenter having a diameter of 40 μm is indented into the surface made of the inorganic material using a nanoindenter under conditions of an indentation depth of at least one of 10 nm and 20 nm. 2 That's all.

[0007] According to the bonded structure of the present invention configured as described above, since the surface is made of an inorganic material, it is less likely to decompose or change in quality due to heat, and is less likely to contaminate the adherend. Furthermore, according to the bonded structure of the present invention, since the elastic modulus of the surface made of an inorganic material is 50 GPa or less, when the surface is pressed by the adherend, it deforms along the adherend, increasing the contact area between the surface and the adherend, thereby improving the adhesive strength to the adherend. Therefore, the adhesive strength can be increased to 35 N / cm 2 Furthermore, according to the bonded structure of the present invention, the elastic modulus of the surface made of an inorganic material is 0.01 GPa or more, so that the surface is easily restored to its original shape when it is separated from the adherend and released from the pressurized state. Therefore, the bonded structure of the present invention has high adhesive strength and can be used repeatedly.

[0008] Here, in the bonded structure of the present invention, the surface made of the inorganic material may have a modulus of elasticity of 0.1 GPa or more. In this case, the elastic protrusions have a high restoring force, and therefore the adhesive structure has improved stability of adhesive strength when used repeatedly.

[0009] In the bonded structure of the present invention, the surface made of the inorganic material may have elastic protrusions. In this case, when the surface is pressed by the adherend, the elastic protrusions deform along with the adherend, so that the elastic modulus and adhesive strength of the surface can be adjusted relatively easily within the range of the present invention.

[0010] In the bonded structure of the present invention, the surface of the inorganic material is 2 The number of elastic protrusions per unit is 1 x 10 9 The number of the electrodes may be more than one. In this case, since there are a large number of elastic protrusions, the contact area between the elastic protrusions and the adherend becomes large when the surface is pressed by the adherend, thereby improving the adhesive strength of the bonded structure.

[0011] In the bonded structure of the present invention, the inorganic material may be a metal. In this case, thermal decomposition and deterioration are less likely to occur, and the elastic modulus of the surface is increased, thereby improving the restoring force, and therefore the adhesive strength of the bonded structure is more stable even when used repeatedly.

[0012] In the bonded structure of the present invention, the metal may include any one of copper, a copper alloy, aluminum, an aluminum alloy, and a NiP alloy. In this case, the elastic modulus of the surface is further increased, further improving the restoring force, and therefore the adhesive structure has further improved stability of adhesive strength when used repeatedly. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an adhesive structure that is resistant to thermal decomposition and deterioration, has high adhesive strength, and can be used repeatedly. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view of a bonded structure according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 2 is a plan view of the bonded structure shown in FIG. [Figure 5] FIG. 2 is a perspective view of a protrusion of the adhesive structure shown in FIG. [Figure 6] 4 is a focus curve of a protrusion of the bonded structure according to the first embodiment of the present invention. [Figure 7] 6A is a conceptual diagram showing the state (FIG. 6A) before the probe of the nanoindenter is pressed into the protrusion of the bonded structure according to the first embodiment of the present invention. FIG. [Figure 8] 6B is a conceptual diagram showing a state in which the probe of a nanoindenter is pressed into a protrusion of the bonded structure according to the first embodiment of the present invention. FIG. [Figure 9] 6C is a conceptual diagram showing a state in which the probe of the nanoindenter that has been pressed into the protrusion of the bonded structure according to the first embodiment of the present invention is pulled up (FIG. 6C). [Figure 10] 6D] FIG. 6D is a conceptual diagram showing a state in which the probe of the nanoindenter pressed into the protrusion of the bonded structure according to the first embodiment of the present invention has been released from the bonded structure. [FIG. [Figure 11] FIG. 10 is a perspective view of a bonded structure according to a second embodiment of the present invention. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. [Figure 13] FIG. 12 is a plan view of the bonded structure shown in FIG. [Figure 14] FIG. 12 is a perspective view of a protrusion of the adhesive structure shown in FIG. [Figure 15] FIG. 10 is a perspective view of a bonded structure according to a third embodiment of the present invention. [Figure 16] 16 is a cross-sectional view of the bonded structure shown in FIG. 15 taken along line XVI-XVI. [Figure 17] FIG. 16 is a plan view of the bonded structure shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an adhesive structure according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0016] [First embodiment] Fig. 1 is a perspective view of a bonded structure according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1, Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1, and Fig. 4 is a plan view of the bonded structure shown in Fig. 1. Fig. 5 is a perspective view of a protrusion of the bonded structure shown in Fig. 1. Note that in Figs. 1 to 5, the X, Y, and Z directions intersect with one another. The X direction represents the first direction, and the Y direction represents the second direction. The Z direction represents the height direction of the protrusion.

[0017] As shown in Figures 1 to 5, an adhesive structure 10 according to this embodiment includes a base 11 and a protrusion 12 provided on one surface of the base 11. The protrusion 12 has a plurality of elastic protrusions 13. The base 11 and the elastic protrusions 13 are integrated. The elastic protrusions 13 have the property of deforming when pressurized and restoring to their original shape when the pressurized state is released.

[0018] The bonded structure 10 is made of an inorganic material. Examples of inorganic materials that can be used include metals, ceramics, and glass. The inorganic material preferably has a melting point of 100°C or higher and a decomposition temperature of 100°C or higher. The metal may be a simple metal or an alloy. Alloys include those composed of multiple metal elements and those composed of a metal element and a non-metal element. Examples of simple metals include aluminum, nickel, iron, and copper. Examples of alloys include aluminum alloys, NiP, stainless steel, and copper alloys. Examples of ceramics that can be used include oxides, nitrides, and carbides. Examples of ceramics include alumina. The inorganic material constituting the bonded structure 10 is preferably a metal, and more preferably contains copper, copper alloys, aluminum, aluminum alloys, or NiP alloys.

[0019] The substrate 11 is plate-shaped. There is no particular limitation on the size of the substrate 11. The thickness of the substrate 11 is, for example, in the range of 10 μm to 10 cm.

[0020] The elastic protrusion 13 has a pointed portion 14 and a body portion 17 extending from the pointed portion 14 toward the base 11. The pointed portion 14 has a pointed tip. The pointed portion 14 has an apex 15 at the center in the first direction (X direction) and extending along the second direction (Y direction), inclined surfaces 16a and 16b that are inclined in opposite directions in the first direction relative to the apex 15, and inclined surfaces 16c and 16d that are inclined in opposite directions in the second direction relative to the apex 15. The bottom surface 18 of the elastic protrusion 13 is rectangular.

[0021] 2 and 3, the pointed portion 14 of the elastic protrusion 13 has a trapezoidal cross section (yz plane) perpendicular to the first direction (X direction) and a triangular cross section (xz plane) perpendicular to the second direction (Y direction). The triangular shape of the pointed portion 14 is preferably an isosceles triangle. The base angle of the isosceles triangle (θ in FIG. 3) is preferably 60 degrees or greater.

[0022] In the protrusion portion 12, the elastic protrusions 13 are periodically arranged in both the first direction (X direction) and the second direction (Y direction). The average pitch L11 of the elastic protrusions 13 in the first direction is, for example, in the range of 100 nm to 1500 nm. The average pitch L11 of the elastic protrusions 13 in the first direction is the distance between the tops 15 of the adjacent elastic protrusions 13 (P in FIGS. 3 and 4). X ) The average pitch L12 of the elastic protrusions 13 in the second direction is within the range of 100 nm to 1500 nm. The average pitch L12 of the elastic protrusions 13 in the second direction is the distance between the centers of the tops 15 of adjacent elastic protrusions 13 (P in FIGS. 2 and 4). Y ) The average pitch L11 in the first direction and the average pitch L12 in the second direction can be measured, for example, from an SEM (scanning electron microscope) photograph of the plane or cross section of the bonded structure 10. In the first direction and the second direction, the distance between adjacent elastic protrusions 13 is preferably within the range of 1 nm to 50 nm.

[0023] As shown in FIG. 5, it is preferable that the elastic protrusions 13 satisfy the following relationship, where the average pitch in the first direction (X direction) is L11, the average pitch in the second direction (Y direction) is L12, the length of the top 15 is L13, the average height of the pointed portion 14 is D11, the average height of the body portion 17 is D12, and the average height of the elastic protrusions 13 (D11+D12) is D13. The ratio of D13 to the longer of L11 and L12, D13 / (L11 or L12), is preferably within the range of 0.7 or more and 10 or less. D13 / (L11 or L12) is more preferably 0.85 or more, and particularly preferably 1.00 or more. D13 is preferably in the range of 100 nm or more and 2000 nm or less. D13 is more preferably 1000 nm or less, and particularly preferably 500 nm or less. However, D12 may be 0. In other words, the elastic protrusion 13 does not need to have a body portion 17. The ratio of L13 to L12 (L13 / L12) is preferably within the range of 0.4 to 0.9, although L12 and L13 may be the same.

[0024] In the bonded structure 10, when the protrusions 12 are pressed by the adherend, the elastic protrusions 13 deform along the adherend, increasing the contact area between the elastic protrusions 13 and the adherend, thereby improving the adhesive strength to the adherend. Furthermore, when the elastic protrusions 13 detach from the adherend and are released from the pressurized state, they restore their original shape, thereby recovering their adhesive strength. When L11, L12, L13, D11, D12, and D13 are within the above ranges, the elastic protrusions 13 are more likely to deform along the adherend, improving their ability to conform to the shape of the adherend. Furthermore, when the adherend detaches from the protrusions 12 and the elastic protrusions 13 are released from the pressurized state, their restoring force is increased.

[0025] The density of the elastic protrusions 13 is 1 cm of the protrusions 12 (surface) of the adhesive structure 10. 2 The number of elastic protrusions 13 per unit is 1 x 10 9 book / cm 2 The density of the elastic protrusions 13 is preferably 5×10 9 book / cm2 Over 5000 x 10 9 book / cm 2 It is more preferable that it is within the following range:

[0026] The surface (protrusions 12) of the bonded structure 10 has a modulus of elasticity in the range of 0.01 GPa or more and 50 GPa or less. A surface modulus of elasticity of 0.01 GPa or more increases the restoring force of the elastic protrusions 13. On the other hand, a surface modulus of elasticity of 50 GPa or less increases the ability to conform to the shape of the adherend. A surface modulus of elasticity of 0.1 GPa or more is preferable. The surface modulus of elasticity of the bonded structure 10 can be measured by pressing a probe into the surface of the bonded structure 10 using a nanoindenter. In this embodiment, a spherical indenter with a diameter of 40 μm was used as the probe 50. The surface modulus of elasticity was determined when the probe's penetration depth was 1 / 10 of the height of the protrusions 12.

[0027] The adhesive structure 10 has an adhesive strength of 35 N / cm when a spherical indenter with a diameter of 40 μm is pressed into the surface of the adhesive structure 10 using a nanoindenter to an indentation depth of at least one of 10 nm and 20 nm. 2 That is said to be the case. The adhesive strength of the bonded structure 10 can be determined by creating a focus curve using a nanoindenter. Fig. 6 is a focus curve of the protrusion 12 of the bonded structure 10 of this embodiment. Fig. 7 is a conceptual diagram showing the state (A in Fig. 6) before the probe 50 of the nanoindenter is pressed into the protrusion 12 of the bonded structure 10. Fig. 8 is a conceptual diagram showing the state (B in Fig. 6) after the probe 50 of the nanoindenter has been pressed into the protrusion 12 of the bonded structure 10. Fig. 9 is a conceptual diagram showing the state (C in Fig. 6) after the probe 50 of the nanoindenter pressed into the protrusion 12 of the bonded structure 10 has been pulled up. Fig. 10 is a conceptual diagram showing the state (D in Fig. 6) after the probe 50 of the nanoindenter pressed into the protrusion 12 of the bonded structure 10 has been released from the bonded structure.

[0028] 7, when the bonded structure 10 and the probe 50 are separated, no load is applied between the protrusion 12 of the bonded structure 10 and the probe 50 (A in FIG. 6). In this embodiment, a spherical indenter with a diameter of 40 μm was used as the probe 50.

[0029] To create a focus curve, first, the probe 50 is pressed into the protrusion 12 of the bonded structure 10 with a predetermined load. The conditions for pressing the probe 50 vary depending on the shape of the probe 50. When the probe 50 is a spherical indenter with a diameter of 40 μm, the pressing is performed under conditions of a load of 20 μN to 100 μN and a pressing speed of 10 nm / sec to 20 nm / sec. The pressing of the probe 50 causes the protrusion 12 of the bonded structure 10 to deform in accordance with the shape of the probe 50. As the pressing depth of the probe 50 increases, the amount of deformation of the protrusion 12 increases. Then, as shown in FIG. 8, pressing of the probe 50 is stopped when the probe 50 has been pressed to a predetermined depth (B in FIG. 6). In this embodiment, the pressing depth of the probe 50 is set to 10 nm or 20 nm.

[0030] Next, the probe 50 is pressed into the protrusion 12 with a predetermined load and held there for a predetermined time, and then the probe 50 is pulled up from the protrusion 12. The conditions for pulling up the probe 50 vary depending on the shape of the probe 50. When the probe 50 is a spherical indenter with a diameter of 40 μm, the pulling speed is set to a range of 10 nm / sec to 20 nm / sec. By pulling up the probe 50, the load applied to the protrusion 12 decreases, and the protrusion 12 returns to its original shape. Furthermore, when the probe 50 is pulled up, the probe 50 and the protrusion 12 do not separate even when the load is removed, and the adhesive force is observed as a negative load. Furthermore, when the probe 50 is pulled up, the probe 50 detaches from the protrusion 12, and the load applied to the protrusion 12 becomes zero. Then, as shown in FIG. 9, the probe 50 and the protrusion 12 completely detach (D in FIG. 6). The maximum negative value of the load (C in FIG. 6, unit: N) from when this negative load is observed until the probe 50 is released from the protrusion 12 is defined as the contact area (cm ) between the probe 50 and the protrusion 12 when the probe 50 is pressed in. 2 ) is the adhesive strength of the protrusion 12.

[0031] The bonded structure 10 of this embodiment can also be manufactured by a method including, for example, a polishing step, a cutting step, and an etching step. In the polishing step, the surface of the raw inorganic material substrate is polished. The inorganic material substrate can be polished, for example, by grinder polishing, polishing with waterproof paper, or buff polishing. The surface of the inorganic material substrate after polishing preferably has a surface roughness Ra of 0.02 μm or less.

[0032] In the cutting process, the surface of the inorganic material substrate polished in the polishing process is cut to form a pointed portion. There are no particular limitations on the cutting method, and various methods can be selected. As the cutting method, for example, a method in which a cutting tool is periodically moved up and down while moving the cutting tool in a direction perpendicular to the cutting surface to form a groove (NP method: nanopecking method), or a method in which a cutting tool is moved linearly without moving up and down to form a groove (conventional method) can be used.

[0033] In the NP method, a processing device having a cutting tool and an ultrasonic vibration device that ultrasonically vibrates the cutting tool can be used as the processing device. The shape of the cutting edge of the cutting tool is not particularly limited, and can be, for example, triangular or rectangular. In the NP method, for example, the cutting tool is ultrasonically vibrated while being pressed obliquely into the surface of the inorganic material substrate, and then the cutting tool is periodically moved up and down while being moved in a direction perpendicular to the cutting edge. This forms triangular wave-shaped protrusions on the surface of the inorganic material substrate, each having a plurality of inverted triangular grooves extending in a direction perpendicular to the movement direction of the cutting tool.

[0034] In the conventional method, a processing device having a cutting tool and an ultrasonic vibration device that ultrasonically vibrates the cutting tool can be used as the processing device. The shape of the cutting edge of the cutting tool can be, for example, triangular or rectangular. In the conventional method, for example, the cutting tool is pressed vertically into the surface of the inorganic material substrate while being ultrasonically vibrated, and then the cutting tool is moved in a direction perpendicular to the cutting edge while being fixed so as not to move up and down. This forms an inverted triangular groove extending parallel to the direction of movement of the cutting tool on the surface of the inorganic material substrate.

[0035] In the cutting step, the NP method and the conventional method may be used in combination. For example, first, triangular wave-shaped protrusions are formed using the NP method, and then grooves are formed in a direction perpendicular to the triangular wave-shaped protrusions using the conventional method, and the triangular wave-shaped protrusions are cut to form pointed portions.

[0036] In the etching process, the body portion is formed by etching the first and second grooves, leaving the pointed portion formed in the cutting process. Various etching methods used for inorganic materials can be used as the etching method. When the inorganic material substrate is made of aluminum, electrolytic etching can be used as the etching method. Etching by electrolytic etching can be performed as follows. First, a polycarbonate film (manufactured by AGC, 50 μm thick) is heated to 150°C and then attached to the pointed portion, and a protective layer is formed on the pointed portion. Next, the inorganic material substrate is immersed in a 1N HCl aqueous solution (manufactured by Kanto Chemical) to perform electrolytic etching, thereby etching the first and second grooves of the inorganic material substrate (immersion rate of 100 nm / min). After etching is completed, the substrate is washed with pure water, and the polycarbonate film is dissolved and removed using methylene chloride. When the inorganic material substrate is made of a material other than aluminum, an iron chloride method can be used as the etching method. When using the iron chloride method, a PVA film (Poval, manufactured by Kuraray, 10 μm thick) is attached to the pointed portion to provide a protective layer. The inorganic material substrate is then immersed in a ferric chloride solution (manufactured by Toa Gosei) with a concentration of 40°Be to etch the first and second grooves of the substrate. After etching is complete, the substrate is washed with pure water to dissolve and remove the PVA film.

[0037] In the bonded structure 10 of this embodiment configured as described above, the protrusions 12 (surfaces) are made of an inorganic material, so they are less likely to decompose or change in quality due to heat and are less likely to contaminate the adherend. Furthermore, in the bonded structure 10 of this embodiment, the protrusions 12 have the above-mentioned elastic modulus and adhesive strength, so that the bonded structure 10 has high adhesive strength and can be used repeatedly.

[0038] In the bonded structure 10 of this embodiment, when the elastic modulus of the protrusions 12 is 0.1 GPa or more, the elastic protrusions 13 have a higher restoring force when released from a pressurized state, which improves the stability of the adhesive force when the bonded structure 10 is used repeatedly.

[0039] In the bonded structure 10 of this embodiment, the protrusions 12 have the elastic protrusions 13, so that the elastic modulus and adhesive strength of the protrusions 12 can be adjusted relatively easily to the above-mentioned values.

[0040] In the bonded structure 10 of this embodiment, 2 The number of elastic protrusions 13 is 1 x 10 9 When the number of elastic protrusions 13 is more than 10, the contact area between the elastic protrusions 13 and the adherend increases when the protrusions 12 are pressed by the adherend, thereby improving the adhesive strength of the bonded structure 10.

[0041] In the bonded structure 10 of this embodiment, if the inorganic material constituting the protrusions 12 is a metal, thermal decomposition or deterioration is less likely to occur, and the surface elastic modulus of the protrusions 12 is higher, improving the restoring force when the elastic protrusions 13 are released from a pressurized state. Therefore, the bonded structure 10 has improved stability of adhesive force even after repeated use. In particular, if the inorganic material constituting the protrusions 12 is copper, a copper alloy, aluminum, an aluminum alloy, or a NiP alloy, the surface elastic modulus of the protrusions 12 is even higher, further increasing the restoring force. Therefore, the bonded structure 10 has improved stability of adhesive force even after repeated use.

[0042] According to the bonded structure 10 of this embodiment, the pointed portion 14 of the elastic protrusion 13 has a shape with inclined surfaces 16a and 16b that are inclined in opposite directions from each other via the apex 15, so that the contact area with the adherend can be increased, thereby further increasing the adhesive strength of the bonded structure 10.

[0043] In the adhesive structure 10 of this embodiment, the pointed portion 14 of the elastic protrusion 13 has been described as having inclined surfaces 16a and 16b that are inclined in opposite directions in a first direction relative to the apex 15, and inclined surfaces 16c and 16d that are inclined in opposite directions in a second direction relative to the apex 15, but is not limited to this. The shape of the pointed portion 14 of the elastic protrusion 13 may be, for example, a cone shape, a quadrangular pyramid shape, or a similar pyramidal shape. The elastic protrusion 13 may also be wavy.

[0044] [Second embodiment] Fig. 11 is a perspective view of a bonded structure according to a second embodiment of the present invention. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 11, and Fig. 13 is a plan view of the bonded structure shown in Fig. 11. Fig. 14 is a perspective view of a protrusion of the bonded structure shown in Fig. 11.

[0045] 11 to 14, the bonded structure 20 according to this embodiment has a base 21 and a plurality of protrusions 22 provided on one surface of the base 21. The base 21 and the protrusions 22 are integral with each other. The bonded structure 20 according to this embodiment differs from the bonded structure 10 of the first embodiment in that the elastic protrusions 23 of the protrusions 22 have a quadrangular pyramid shape.

[0046] The bonded structure 20 is made of an inorganic material. Examples of inorganic materials that can be used include metal, ceramic, and glass. The inorganic material preferably has a melting point of 100°C or higher and a decomposition temperature of 100°C or higher. Examples of metals and ceramics are the same as those in the bonded structure 10 of the first embodiment. The substrate 21 is the same as the substrate 11 of the bonded structure 10 of the first embodiment.

[0047] It is preferable that the inclined surfaces 26a, 26b, 26c, and 26d forming the quadrangular pyramid of the elastic protrusion 23 are each the same isosceles triangle. The base surface 28 is preferably a square. The base angle of the isosceles triangle of the pointed portion 24 (θ in FIG. 12) is preferably 60 degrees or more.

[0048] The protrusions 22 are periodically arranged in both the first direction (X direction) and the second direction (Y direction). The average pitch of the elastic protrusions 23 in the first direction is in the range of 100 nm to 1500 nm. The average pitch of the elastic protrusions 23 in the first direction is the distance between the vertices 25 of adjacent elastic protrusions 23 (P in FIGS. 12 and 13 ). X ) The average pitch of the elastic protrusions 23 in the second direction is in the range of 100 nm to 1500 nm. The average pitch of the protrusions 22 in the second direction is the distance between the vertices 25 of the adjacent elastic protrusions 23 (P in FIG. 13 ). Y ) The average pitch of the elastic protrusions 23 in the first direction and the second direction can be measured from an SEM photograph of the plan or cross section of the bonded structure 10 taken with an SEM. The interval between adjacent elastic protrusions 23 in the first direction and the second direction is preferably 1 nm or more and 50 nm or less.

[0049] As shown in FIG. 14, it is preferable that the elastic protrusion 23 satisfies the following relationship, where L21 is the length of the bottom surface 28 in the first direction (X direction), L22 is the length of the bottom surface 18 in the second direction (Y direction), D21 is the average height of the pointed portion 24, D22 is the average height of the body portion 27, and D23 is the average height (D21+D22) of the protrusion portion 12. The ratio of D23 to L21 (D23 / L21) is preferably within the range of 0.7 or more and 10 or less. D23 / L21 is more preferably 0.85 or more, and particularly preferably 1.00 or more. D23 is preferably in the range of 100 nm or more and 2000 nm or less, more preferably 1000 nm or less, and particularly preferably 500 nm or less.

[0050] The bonded structure 20 of this embodiment can be manufactured in the same manner as the bonded structure 10 of the first embodiment. However, when manufacturing the bonded structure 20 of this embodiment, the second groove is formed in the cutting step so that no apex remains. This forms a pointed portion 24 in the shape of a quadrangular pyramid.

[0051] The bonded structure 20 of the second embodiment configured as described above has the protrusions 22 (surface) made of an inorganic material, and the surface elastic modulus and adhesive strength are within the above-mentioned ranges, so it has the same effects as the bonded structure 10 of the first embodiment. Furthermore, in the bonded structure 20 of the second embodiment, the pointed portions 24 of the elastic protrusions 23 are quadrangular pyramidal in shape, so that even if the pointed portions 24 deform, the pointed portions 24 of adjacent elastic protrusions 23 are less likely to come into contact with each other. Therefore, when pressure is applied by the adherend, the elastic protrusions 23 deform by a large amount, and their ability to follow the adherend increases. Therefore, the bonded structure 20 of this embodiment has high adhesive strength and can stably adhere and hold the adherend in a variety of environments.

[0052] [Third embodiment] Fig. 15 is a perspective view of a bonded structure according to a third embodiment of the present invention, Fig. 16 is a cross-sectional view of the bonded structure shown in Fig. 15 taken along line XVI-XVI, and Fig. 17 is a plan view of the bonded structure shown in Fig. 15.

[0053] 15 to 17, the bonded structure 30 according to this embodiment has a base 31 and a plurality of protrusions 32 provided on one surface of the base 31. The base 31 and the protrusions 32 are integral with each other. The bonded structure 30 according to this embodiment differs from the bonded structure 10 according to the first embodiment in that the protrusions 32 are wavy.

[0054] The bonded structure 30 is made of an inorganic material. Examples of inorganic materials that can be used include metal, ceramic, and glass. The inorganic material preferably has a melting point of 100°C or higher and a decomposition temperature of 100°C or higher. Examples of metals and ceramics are the same as those in the bonded structure 10 of the first embodiment. The substrate 31 is the same as the substrate 11 of the bonded structure 10 of the first embodiment.

[0055] The protrusion portion 32 is configured with a plurality of elongated elastic protrusions 33 arranged along the longitudinal direction. The cross-sectional shape of the elastic protrusions 33 is triangular. The cross-sectional shape of the elastic protrusions 33 is preferably an isosceles triangle. The base angle of the elastic protrusions 33 (θ in FIG. 16) is preferably 60 degrees or more, and is preferably in the range of 60 degrees to 80 degrees.

[0056] The average pitch of the protrusions 32 is in the range of 100 nm to 1000 nm, and preferably 500 nm or less. The average pitch of the protrusions 32 is the average value of the distances (P in FIGS. 16 and 17) between the apexes 33a of adjacent elastic protrusions 33 of the protrusions 32. The average pitch of the protrusions 32 can be measured from a cross-sectional SEM photograph of the bonded structure 30 taken with an SEM.

[0057] The average height of the protrusions 32 is in the range of 100 nm to 1000 nm, and preferably 500 nm or less. The average height of the protrusions 32 is the average of the heights of the elastic protrusions 33 (H in FIG. 16 ) with the base being the space between the valleys 33b of the elastic protrusions 33 of the protrusions 32. The average height of the protrusions 32 can be measured from a cross-sectional SEM photograph of the bonded structure 30 taken with an SEM.

[0058] The ratio of the average height of the protrusions 32 to the average pitch (average height / average pitch) is preferably in the range of 0.8 to 2.0, more preferably in the range of 1.0 to 1.5.

[0059] The bonded structure 30 of the present invention can be manufactured in the same manner as the bonded structure 10 of the first embodiment. However, when manufacturing the bonded structure 30 of this embodiment, it is not necessary to form the second grooves in the cutting step, and only the first grooves are formed. This results in the formation of wavy protrusions.

[0060] The bonded structure 30 of the third embodiment configured as described above has the protrusions 32 (surface) made of an inorganic material and has a surface elastic modulus and adhesive strength within the above ranges, and therefore has the same effects as the bonded structure 10 of the first embodiment. Furthermore, the bonded structure 30 of the third embodiment has the effect of being less likely to have planar anisotropy in adhesive strength because the protrusions 32 are wavy.

[0061] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention. For example, in the bonded structures 10, 20, and 30 of the present embodiment, the protrusions 12, 22, and 32 are provided over the entire surface of one surface (upper surface) of the base 11, 21, and 31, but the positions of the protrusions 12, 22, and 32 are not limited to this. The protrusions 12, 22, and 32 may be provided on both surfaces of the base 11, 21, and 31. Furthermore, the protrusion 22 may be provided on a portion of the surface of the base 11, 21, and 31.

[0062] Furthermore, in the bonded structures 10, 20, and 30 of the present embodiment, the bases 11, 21, and 31 are made of an inorganic material, but the configuration of the bases 11, 21, and 31 is not limited to this. If at least a portion of the protrusions 12, 22, and 32 (surfaces) is made of an inorganic material, the bases 11, 21, and 31 may be a composite in which the surface of a resin material is coated with an inorganic material. Note that, when the bonded structures 10, 20, and 30 are composites, it is preferable that 50% or more of the surface is coated with an inorganic material and the protrusions 12, 22, and 32 are formed thereon. [Example]

[0063] [Example 1] A metal aluminum substrate (length: 30 mm, width: 30 mm, thickness: 30 mm) was prepared as the substrate. The surface of the prepared metal aluminum substrate was polished until the surface roughness Ra became 0.02 μm or less, to form a smooth surface.

[0064] Next, triangular wave-shaped protrusions were formed on the polished surface of the metal aluminum base material using the NP method. The processing device used was a processing device equipped with a cutting tool and an ultrasonic vibration device that ultrasonically vibrates the cutting tool. The cutting tool was inserted obliquely while ultrasonically vibrating, and then, while ultrasonically vibrating the cutting tool, it was moved 1000 nm in a direction (first direction) perpendicular to the blade surface while moving the cutting tool at a period in which the cutting edge moved 1000 nm up and down. This formed first grooves in the shape of inverted equilateral triangles extending in a direction (second direction) perpendicular to the direction of movement of the cutting tool (first direction) on the surface of the metal aluminum base material, and produced a substrate with triangular wave-shaped protrusions having equilateral triangular wave-shaped protrusions with an average pitch of 1000 nm and an average height of 1000 nm.

[0065] Next, the equilateral triangular wave-shaped protrusions of the triangular wave-shaped protrusion-bearing substrate were cut using a conventional method. The processing device used was a processing device equipped with a cutting tool and an ultrasonic vibration device that ultrasonically vibrates the cutting tool. The cutting tool had a rectangular shape with a cutting edge width of 300 nm. The cutting tool was pressed into the triangular wave-shaped protrusions while ultrasonically vibrating it. Next, while fixing the cutting tool so that it did not move up and down, the cutting tool was moved in a direction (first direction) perpendicular to the direction in which the grooves of the triangular wave-shaped protrusions extend (second direction), forming second grooves with a width of 300 nm at a pitch of 1000 nm. As shown in Figures 1 to 5, a pointed portion was formed whose cross section perpendicular to the first direction was trapezoidal and whose cross section perpendicular to the second direction was equilateral triangular. In this way, a substrate with protrusions was obtained. The average pitch L11 in the first direction and the average pitch L12 in the second direction of the protrusions of the obtained substrate with protrusions, the average length L13 of the top, the average height D11 of the pointed portion, the average height D12 of the body portion, and the average height D13 of the protrusions are shown in Table 1 below.

[0066] [Inventive Examples 2 to 8, Comparative Examples 1 and 2] A substrate with protrusions was produced in the same manner as in Example 1 of the present invention, except that a metal substrate made of the material listed in Table 1 below was used as the substrate, and that the substrate was cut so that the average pitch in the first direction L11, the average pitch in the second direction L12, the average length of the apex L13, the average height of the pointed portion D11, the average height of the body D12, and the average height of the protrusions D13 were the values ​​listed in Table 1 below.

[0067] [evaluation] The density of the elastic protrusions and the surface elastic modulus were measured and the adhesiveness was evaluated by the following methods for the substrates with protrusions produced in Invention Examples 1 to 8 and Comparative Example 1. The results are shown in Table 1.

[0068] (Method for measuring density of elastic protrusions) The morphology of the substrate with protrusions was observed using a SEM (scanning electron microscope), and the number of protrusions per unit area was counted. The number of protrusions per unit area was then calculated as 1 cm 2 This was converted into the number of protrusions per unit area (density).

[0069] (Method for measuring surface elastic modulus) Measurements were performed using a nanoindenter (ENT-NEXUS, manufactured by Elionix Co., Ltd.). A spherical indenter (made of titanium) with a diameter of 40 μm was used as the probe. The load was increased from 20 μN to 100 μN in 10 μN increments, and the surface elastic modulus was measured at each load. The surface elastic modulus when the probe's indentation depth reached 1 / 10 of the height of the protrusion is shown in Table 1 below. Measurements were performed at room temperature (25°C).

[0070] (Method for evaluating adhesiveness) The adhesive strength was measured using a nanoindenter (ENT-NEXUS, manufactured by Elionix Co., Ltd.) according to the above method. A spherical indenter (titanium) with a diameter of 40 μm was used as the probe. The indentation depth of the spherical indenter was the depth listed in Table 1, similar to the method for measuring the surface elastic modulus described above. The indentation speed of the probe was set to 10 nm / sec when the indentation depth was 10 nm, and 20 nm / sec when the indentation depth was 20 nm. The lift-up speed of the probe was set to 10 nm / sec when the indentation depth was 10 nm, and 20 nm / sec when the indentation depth was 20 nm. The measurements were carried out at room temperature (25°C).

[0071] [Table 1]

[0072] The results in Table 1 show that protrusion-equipped substrates in which the pointed portions of the elastic protrusions have inclined surfaces that are inclined in opposite directions in a first direction from the apex, and inclined surfaces that are inclined in opposite directions in a second direction from the apex, can have surface elastic moduli and adhesive strengths that fall within the ranges of the present invention, depending on the shape of the protrusions (Invention Examples 1 to 8).The protrusion-equipped substrates of Inventive Examples 1 to 8 have high adhesive strength and surface elastic moduli that are within the range of the present invention, allowing for repeated use.In contrast, the protrusion-equipped substrate of Comparative Example 1, in which the size of the protrusions formed on the surface is fine, has a surface elastic modulus that is higher than the range of the present invention, so is less likely to deform when pressure is applied with an adherend, and adhesive strength is reduced.

[0073] [Example 9] A blade with an equilateral triangle shape with a tip angle of 60 degrees was used to cut the equilateral triangular waveform-shaped protrusions of the triangular-wave-shaped-protrusion substrate, and the blade was moved in a direction (first direction) perpendicular to the direction (second direction) in which the grooves of the triangular waveform-shaped protrusions extended, forming second grooves with inverted equilateral triangular cross sections at a pitch of 1000 nm, and forming pointed portions in the shape of regular square pyramids as shown in Figures 11 to 14. A protrusion-bearing substrate was obtained in the same manner as in Invention Example 1. The average pitch L21 in the first direction and the average pitch L22 in the second direction of the protrusions of the obtained protrusion-bearing substrate, as well as the average height D21, the average height D22 of the body portions, and the average height D23 of the protrusions are shown in Table 1 below.

[0074] [Invention Examples 10 to 12, Comparative Example 2] A substrate with protrusions was produced in the same manner as in Example 9 of the present invention, except that a metal substrate made of the material listed in Table 1 below was used as the substrate, and that the substrate was cut so that the average pitch L21 in the first direction, the average pitch L22 in the second direction, the average height D21 of the pointed portion, the average height D22 of the body portion, and the average height D23 of the protrusions were the values ​​listed in Table 2 below.

[0075] [Example 13] A polycarbonate film (manufactured by AGC, 50 μm thick) was heated to 150°C, and the heated polycarbonate film was attached to the pointed portion, side, and bottom of the protrusion-equipped substrate obtained in Invention Example 9, forming a protective layer on the protrusion-equipped substrate. Next, the protrusion-equipped substrate with the protective layer formed thereon was immersed in a 1N HCl aqueous solution (manufactured by Kanto Chemical) and electrolytic etching was performed for 20 seconds, thereby etching the first and second grooves in the protective layer on the protrusion-equipped substrate. Next, the protrusion-equipped substrate was washed with pure water, and the protective layer (polycarbonate film) was dissolved and removed using methylene chloride. In this way, body portions with the average heights shown in Table 2 were formed on the protrusions.

[0076] [Example 14] A PVA film (Poval, manufactured by Kuraray, 10 μm thick) was attached to the pointed portion, side, and bottom of the protrusion-equipped substrate obtained in Example 10 of the present invention, forming a protective layer on the protrusion-equipped substrate. The protrusion-equipped substrate with the protective layer formed thereon was then immersed in a ferric chloride solution (manufactured by Toa Gosei) with a concentration of 40°Be for 30 seconds, thereby etching the first and second grooves in the protective layer on the protrusion-equipped substrate by the ferric chloride method. The protrusion-equipped substrate was then washed with pure water to dissolve and remove the protective layer (PVA film). In this way, body portions with the average heights shown in Table 2 were formed on the protrusions.

[0077] [Examples 15 and 16] The substrate with protrusions obtained in Inventive Example 11 was used, and etching was carried out by the iron chloride method in the same manner as Inventive Example 14, except that the immersion time in the ferric chloride solution was 10 seconds (Inventive Example 15) or 20 seconds (Inventive Example 16). In this way, body portions with the average heights shown in Table 2 were formed on the protrusions.

[0078] [Example 17] The substrate with protrusions obtained in Inventive Example 12 was used, and etching was carried out in the same manner as Inventive Example 13, except that electrolytic etching was carried out for 10 seconds. In this way, body portions having the average heights shown in Table 2 were formed on the protrusions.

[0079] [Examples 18 and 19] A substrate with protrusions was produced in the same manner as in Invention Example 9, except that a substrate made of NiP was used as the substrate and was cut so that the average pitch L21 in the first direction, the average pitch L22 in the second direction, the average height D21 of the pointed portions, the average height D22 of the body portions, and the average height D23 of the protrusions were the values ​​shown in Table 2 below. Using the obtained substrate with protrusions, etching was carried out by the iron chloride method in the same manner as Invention Example 14, except that the immersion time in the ferric chloride solution was 10 seconds (Invention Example 18) and 10 seconds (Invention Example 19). In this way, body portions having the average heights shown in Table 2 were formed on the protrusions.

[0080] [Table 2]

[0081] The results in Table 2 show that even for protrusion-equipped substrates in which the pointed portions of the elastic protrusions are square pyramidal, depending on the shape of the protrusions, substrates with surface elasticity and adhesive strength within the ranges of the present invention (Invention Examples 9 to 19) can be obtained. These protrusion-equipped substrates of Inventive Examples 9 to 19 have high adhesive strength and surface elasticity within the ranges of the present invention, allowing for repeated use.

[0082] [Examples 20 to 22] The substrates with triangular wave-shaped protrusions produced in Inventive Examples 1 to 3 were used as substrates with protrusions in Inventive Examples 20 to 22, respectively.

[0083] Comparative Example 3 The substrate with triangular wave-shaped protrusions produced in Example 8 of the present invention was used as the substrate with protrusions of Comparative Example 3.

[0084] Comparative Example 4 The substrate with triangular wave-shaped protrusions produced in Comparative Example 1 was used as the substrate with protrusions of Comparative Example 4.

[0085] [evaluation] The surface elastic modulus was measured and adhesion was evaluated by the above-mentioned method for the substrates with protrusions obtained in Inventive Examples 20 to 22 and Comparative Examples 3 and 4. The results are shown in Table 3, along with the average pitch, average height, and average height / average pitch of the protrusions.

[0086] [Table 3]

[0087] The results in Table 3 show that even for protrusion-equipped substrates having wavy protrusions, those with surface elastic modulus and adhesive strength within the range of the present invention can be obtained (Invention Examples 20 to 22) depending on the shape of the protrusions. The protrusion-equipped substrates of Inventive Examples 20 to 22 have high adhesive strength and surface elastic modulus within the range of the present invention, allowing for repeated use. Note that in Comparative Example 3, the equilateral triangular wave-shaped protrusions were not cut, which is thought to have resulted in a higher surface elastic modulus and lower adhesive strength compared to the protrusion-equipped substrate of Inventive Example 8. [Explanation of symbols]

[0088] 10 Adhesive structure 11 Base 12 Protrusion 13 Elastic protrusion 14 Point 15 Top 16a, 16b, 16c, 16d sloped surface 17 Torso 18 bottom 20 Adhesive structure 21 Base 22 Protrusion 23 Elastic protrusion 24 Point 25 Vertex 26a, 26b, 26c, 26d sloped surface 27 Torso 28 bottom 30 Adhesive structure 31 Base 32 Protrusion 33 Elastic protrusion 33a Top 33b Tanibe 50 probe

Claims

1. At least a portion of the surface is made of inorganic material, The elastic modulus of the surface made of the inorganic material is in the range of 0.01 GPa or more and 50 GPa or less, Using a nanoindenter, a spherical indenter with a diameter of 40 μm was pressed into the surface made of the inorganic material to a depth of at least one of 10 nm and 20 nm, and the adhesive strength was 35 N / cm ２ The above is the adhesive structure.

2. The bonded structure according to claim 1 , wherein the surface made of the inorganic material has an elastic modulus of 0.1 GPa or more.

3. The bonded structure according to claim 1 or 2, wherein the surface made of the inorganic material has elastic protrusions.

4. 1 cm of the surface made of the inorganic material ２ The number of the elastic protrusions per unit is 1×10 ９ The bonded structure according to claim 3, wherein the number of strands is 1 or more.

5. The bonded structure according to claim 1 , wherein the inorganic substance is a metal.

6. 6. The bonded structure according to claim 5, wherein the metal comprises any one of copper, copper alloy, aluminum, aluminum alloy, and NiP alloy.

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