Then 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 includes: a substrate; and a protrusion portion having a plurality of protrusions, provided on at least a part of the surface of the substrate. The protrusion portion is composed of inorganic material. The plurality of protrusions are arranged periodically in a first direction and a second direction perpendicular to the first direction, respectively. The protrusions each have a sharp portion with a sharp tip. The average pitch between the protrusions in the first direction is within a range of 100 nm to 1500 nm. The average pitch of the protrusions in the second direction is within a range of 100 nm to 1500 nm. The average height of the protrusions is within a range of 100 nm to 2000 nm.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 adhere 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 made of a resin material. The resin material may be decomposed or altered by heat, which may reduce the adhesive strength. Furthermore, the resin material may contaminate the adherend with decomposition products.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide an adhesive structure that is resistant to thermal decomposition and deterioration and has high adhesive strength. [Means for solving the problem]

[0006] In order to solve the above problems, the adhesive structure of the present invention comprises:An adhesive structure that adhesively holds an object to be adhered, The present invention includes a substrate and a protrusion portion having a plurality of protrusions provided on at least a portion of the surface of the substrate, the protrusion portion being made of an inorganic material, the plurality of protrusions being periodically arranged in a first direction and a second direction intersecting the first direction, the protrusions having sharp tips, the average pitch of the protrusions in the first direction being within the range of 100 nm or more and 1500 nm or less, and the average pitch of the protrusions in the second direction being within the range of 100 nm or more and 1500 nm or less.

[0007] The adhesive structure of the present invention includes a substrate and a protrusion portion having a plurality of protrusions provided on at least a portion of the surface of the substrate. Because the protrusions are made of an inorganic material, they are resistant to thermal decomposition or deterioration and are less likely to contaminate the adherend. Furthermore, the plurality of protrusions are periodically arranged in a first direction and a second direction intersecting the first direction. The protrusions have sharp tips, and the average pitch of the protrusions in the first direction is within the range of 100 nm to 1500 nm, while the average pitch of the protrusions in the second direction is within the range of 100 nm to 1500 nm. This results in a high surface elasticity, a large amount of deformation of the protrusions when pressed by the adherend, and high conformability to the adherend. Therefore, the adhesive structure has a large contact area between the adherend and the protrusions. Therefore, the adhesive structure has high adhesive strength and can stably adhere and hold the adherend in a variety of environments.

[0008] Here, in the bonded structure of the present invention, the projections may have an average height of 100 nm or more. In this case, the average height of the protrusions is 100 nm or more, which reliably increases the surface elasticity, making it possible to more stably adhere and hold the adherend in a variety of environments.

[0009] In the bonded structure of the present invention, the pointed portion of the projection may have a shape having inclined surfaces inclined in opposite directions from the apex, or may have a quadrangular pyramid shape. In this case, the contact area between the pointed portion of the projection and the object to be adhered can be increased, thereby increasing the adhesive strength of the bonded structure.

[0010] In the bonded structure of the present invention, the protrusion may have the pointed portion and a body portion extending from the pointed portion toward the base. In this case, the amount of deformation of the projections when pressed by the adherend increases, resulting in higher conformability to the adherend.

[0011] Furthermore, in the adhesive structure of the present invention, the ratio of the average height of the protrusions to the longer of the average pitch of the protrusions in the first direction and the average pitch of the protrusions in the second direction may be configured to be in the range of 0.7 or more and 10 or less. In this case, the amount of deformation of the projections when pressed by the adherend increases, resulting in higher conformability to the adherend.

[0012] In the bonded structure of the present invention, the average pitch of the protrusions in the first direction may be 500 nm or less, and the average pitch of the protrusions in the second direction may be 500 nm or less. In this case, the number of protrusions per unit area of ​​the protrusion portion increases, so that the contact area with the adherend can be increased, thereby increasing the adhesive strength of the bonded structure.

[0013] In the bonded structure of the present invention, the inorganic material may be a metal. In this case, decomposition or deterioration due to heat is unlikely to occur, and the surface elastic modulus of the protrusions is increased, improving the restoring force after deformation and improving repeatability.

[0014] 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 surface elastic modulus of the protrusions is further increased, resulting in further increased repeatability.

[0015] In addition, in the bonded structure of the present invention, when a spherical indenter having a diameter of 40 μm is pressed into the protrusions to a depth of at least 10 nm or 20 nm using a nanoindenter, the adhesive strength is 35 N / cm 2 The above configuration may be adopted. In this case, it can be suitably used as an adhesive structure with high adhesive strength. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an adhesive structure that is resistant to thermal decomposition and deterioration and has high adhesive strength. [Brief explanation of the drawings]

[0017] [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] 10 is a focus curve of a protrusion of an adhesive structure according to one embodiment of the present invention. [Figure 7] FIG. 6 is a conceptual diagram showing the state (A in FIG. 6) before the probe of the nanoindenter is pressed into the protrusion of the bonded structure according to one embodiment of the present invention. [Figure 8] FIG. 6B is a conceptual diagram showing a state in which the probe of a nanoindenter is pressed into a protrusion of an adhesive structure according to one embodiment of the present invention. [Figure 9] FIG. 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 one embodiment of the present invention is pulled up (FIG. 6C). [Figure 10]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 one embodiment of the present invention has been released from the bonded structure. [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. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an adhesive structure according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0019] [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.

[0020] 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 protrusions 13. The base 11 and the protrusions 13 are integral with each other. The protrusions 13 have the property of deforming when pressurized and restoring to their original shape when the pressurized state is released.

[0021] 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.

[0022] 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.

[0023] The 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 protrusion 13 is rectangular.

[0024] 2 and 3, the pointed portion 14 of the projection 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.

[0025] In the protrusion portion 12, the protrusions 13 are periodically arranged in both the first direction (X direction) and the second direction (Y direction). The average pitch L11 of the protrusions 13 in the first direction is in the range of 100 nm to 1500 nm. The average pitch L11 of the protrusions 13 in the first direction is the distance between the tops 15 of the adjacent protrusions 13 (P in FIGS. 3 and 4). X ) The average pitch L12 of the protrusions 13 in the second direction is in the range of 100 nm to 1500 nm. The average pitch L12 of the protrusions 13 in the second direction is the distance between the centers of the apexes 15 of adjacent protrusions 13 (P in FIGS. 3 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 photograph of the plane or cross section of the bonded structure 10 taken with an SEM (scanning electron microscope). In the first direction and the second direction, the interval between adjacent protrusions 13 is preferably within the range of 1 nm to 50 nm.

[0026] As shown in FIG. 5, it is preferable that the 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 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 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.

[0027] In the bonded structure 10, the protrusions 12 are pressed by the adherend, causing the protrusions 13 to deform along the adherend, increasing the contact area between the protrusions 13 and the adherend, thereby improving the adhesive strength to the adherend. Furthermore, the protrusions 13 recover their adhesive strength by detaching from the adherend and restoring to their original shape when the pressure is released. When L11, L12, L13, D11, D12, and D13 are within the above ranges, the protrusions 13 are more likely to deform along the adherend, improving their ability to conform to the shape of the adherend. Furthermore, the restoring force is increased when the adherend detaches from the protrusions 12 and the protrusions 13 are released from the pressure.

[0028] The adhesive strength of the bonded structure 10 can be determined by creating a focus curve using a nanoindenter. Fig. 6 shows 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 30 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 30 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 30 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 30 of the nanoindenter pressed into the protrusion 12 of the bonded structure 10 has been released from the bonded structure.

[0029] 7, when the bonded structure 10 and the probe 30 are separated, no load is applied between the protrusion 12 of the bonded structure 10 and the probe 30 (A in FIG. 6). In this embodiment, a spherical indenter with a diameter of 40 μm was used as the probe 30.

[0030] To create a focus curve, first, the probe 30 is pressed into the protrusion 12 of the bonded structure 10 with a predetermined load. The conditions for pressing the probe 30 vary depending on the shape of the probe 30. When the probe 30 is a spherical indenter with a diameter of 40 μm, the pressing is performed under conditions of a load of 20 μN or more and 100 μN or less and a pressing speed of 10 nm / sec or more and 20 nm / sec or less. The pressing of the probe 30 causes the protrusion 12 of the bonded structure 10 to deform in accordance with the shape of the probe 30. As the pressing depth of the probe 30 increases, the amount of deformation of the protrusion 12 increases. Then, as shown in FIG. 8, pressing of the probe 30 is stopped when the probe 30 has been pressed to a predetermined depth (B in FIG. 6). In this embodiment, the pressing depth of the probe 30 is set to 10 nm or 20 nm.

[0031] Next, the probe 30 is pressed into the protrusion 12 with a predetermined load and held there for a predetermined time, after which the probe 30 is pulled up from the protrusion 12. The conditions for pulling up the probe 30 vary depending on the shape of the probe 30. When the probe 30 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 30, the load applied to the protrusion 12 decreases, and the protrusion 12 returns to its original shape. Furthermore, when the probe 30 is pulled up, the probe 30 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 30 is pulled up, the probe 30 detaches from the protrusion 12, and the load applied to the protrusion 12 becomes zero. Then, as shown in FIG. 9, the probe 30 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 was observed until the probe 30 was released from the protrusion 12 was defined as the contact area (cm ) between the probe 30 and the protrusion 12 when the probe 30 was pressed in. 2 ) is the adhesive strength of the protrusion 12. The adhesive strength of the protrusion 12 varies depending on the indentation depth of the probe 30. The adhesive structure 10 of this embodiment has an adhesive strength of 35 N / cm at an indentation depth of at least one of 10 nm and 20 nm. 2 It is preferable that this is equal to or greater than this.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The bonded structure 10 of this embodiment, configured as described above, includes a base 11 and a protrusion portion 12 having a plurality of protrusions 13 provided on at least a portion of the surface of the base 11. Because the structure is made of an inorganic material, it is resistant to thermal decomposition or deterioration and is less likely to contaminate the adherend. Furthermore, the plurality of protrusions 13 are periodically arranged in a first direction (X direction) and a second direction (Y direction) perpendicular to the first direction. Each of the protrusions 13 has a pointed portion 14. The average pitch of the protrusions 13 in the first direction is within the range of 100 nm to 1500 nm, and the average pitch of the protrusions 13 in the second direction is within the range of 100 nm to 1500 nm. This results in a high surface elasticity, a large amount of deformation of the protrusions 13 when pressed by the adherend, and high conformability to the adherend. Therefore, the bonded structure 10 of this embodiment has a large contact area between the adherend and the protrusions 13. Therefore, the bonded structure 10 of this embodiment has high adhesive strength and can stably adhere and hold the adherend in a variety of environments. Furthermore, according to the bonded structure 10 of this embodiment, by making the average height of the protrusions 13 100 nm or more, it is possible to reliably improve the ability to conform to the contact surface.

[0039] According to the bonded structure 10 of this embodiment, the pointed portion 14 of the projection 13 has a shape with inclined surfaces 16a and 16b that are inclined in opposite directions from each other through 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.

[0040] In the adhesive structure 10 of this embodiment, when the protrusion 13 has a pointed portion 14 and a body portion 17 extending from the pointed portion 14 toward the base 11, the amount of deformation of the protrusion 13 when pressed by the adherend becomes greater, resulting in higher followability to the adherend.

[0041] In the adhesive structure 10 of this embodiment, when the ratio of the average height D3 of the protrusions 13 to the longer of the average pitch L11 of the protrusions 13 in the first direction and the average pitch L12 of the protrusions 13 in the second direction is within the range of 0.7 or more and 10 or less, the amount of deformation of the protrusions 13 when pressed by the adherend becomes greater, resulting in higher followability to the adherend.

[0042] In the adhesive structure 10 of this embodiment, if the average pitch L11 of the protrusions 13 in the first direction is 500 nm or less and the average pitch L12 of the protrusions 13 in the second direction is 500 nm or less, the number of protrusions 13 per unit area of ​​the protrusion portion 12 increases, thereby making it possible to increase the contact area with the adherend, thereby increasing the adhesive strength of the adhesive structure 10.

[0043] In the bonded structure 10 of this embodiment, when the inorganic material constituting the protrusions 12 is a metal, the surface elastic modulus of the protrusions 12 becomes higher, improving the restoring force after deformation and repeatability. In particular, when 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 becomes even higher, further increasing the adhesive strength.

[0044] In the bonded structure 10 of this embodiment, the adhesive strength was 35 N / cm when the probe 30 was pressed into the protrusion 12 to a pressing depth of at least one of 10 nm and 20 nm using a nanoindenter with a spherical indenter having a diameter of 40 μm as the probe 30. 2 If the adhesive strength is above this, the adhesive strength is high, so that it is unlikely to decompose or change in quality due to heat, and can be suitably used as an adhesive structure with high adhesive strength.

[0045] [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. In Figs. 11 to 14, the X, Y, and Z directions are perpendicular to each other. 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.

[0046] 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 base 21 is the same as the base 11 of the bonded structure 10 according to the first embodiment.

[0047] 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.

[0048] The pointed portion 24 of the protrusion 23 is shaped like a quadrangular pyramid. The inclined surfaces 26a, 26b, 26c, and 26d forming the quadrangular pyramid are preferably identical isosceles triangles. The bottom surface 28 is preferably a square. The base angle (θ in FIG. 12) of the isosceles triangle of the pointed portion 24 is preferably 60 degrees or greater.

[0049] The protrusions 22 are periodically arranged in both the first direction (X direction) and the second direction (Y direction). The average pitch of the protrusions 23 in the first direction is in the range of 100 nm to 1500 nm. The average pitch of the protrusions 23 in the first direction is the distance between the vertices 25 of adjacent protrusions 23 (P in FIGS. 12 and 13 ). X ) The average pitch of the 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 apexes 25 of the adjacent protrusions 23 (P in FIG. 13 ). Y) The average pitch of the protrusions 23 in the first direction and the second direction can be measured from a SEM photograph of the plan or cross section of the bonded structure 10 taken with an SEM (scanning electron microscope). The interval between adjacent protrusions 23 in the first direction and the second direction is preferably 1 nm or more and 50 nm or less.

[0050] As shown in FIG. 14, it is preferable that the 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.

[0051] 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 results in the formation of a pointed portion in a quadrangular pyramid shape. Furthermore, when manufacturing the bonded structure 20 using the second method, after forming a protrusion with a triangular cross section in the cutting step, the protrusion with a triangular cross section is cut so that no apex remains. This results in the formation of a pointed portion in a quadrangular pyramid shape.

[0052] The bonded structure 20 of this embodiment, configured as described above, is made of an inorganic material, and each of the multiple protrusions 23 has a pointed portion. The average pitch L21 of the protrusions 23 in the first direction, the average pitch L22 of the protrusions 23 in the second direction, and the average height D13 of the protrusions 23 are the same as those of the bonded structure 10 of the first embodiment, and therefore has the same effects as the bonded structure 10. Furthermore, in the bonded structure 20 of the second embodiment, the pointed portions 24 of the protrusions 23 are quadrangular pyramid-shaped, and even if the pointed portions 24 deform, the pointed portions 24 of adjacent protrusions 23 are less likely to come into contact with each other. Therefore, when pressure is applied by the adherend, the protrusions 23 deform more greatly, and their ability to conform to the adherend is enhanced. 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.

[0053] 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 and 20 of the present embodiment, the protrusions 12 and 22 are provided over the entire surface (upper surface) of one of the substrates 11 and 21, but the positions of the protrusions 12 and 22 are not limited to this. The protrusions 12 and 22 may be provided on both surfaces of the substrates 11 and 21. Furthermore, the protrusions 12 and 22 may be provided on a portion of the surface of the substrates 11 and 21. [Example]

[0054] [Example 1] The base material is a metal aluminum base material (length: 30 mm , width: 30 mm , Plate thickness: 30 mm 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.

[0055] Next, triangular wave-shaped protrusions were formed on the polished surface of the metal aluminum substrate 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 an inverted equilateral triangle on the surface of the metal aluminum substrate, extending in a direction (second direction) perpendicular to the direction of movement of the cutting tool (first direction), and produced a substrate with triangular wave-shaped protrusions having equilateral triangular wave-shaped protrusions.

[0056] 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.

[0057] [Invention Examples 2 to 8, Comparative Example 1] 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.

[0058] [evaluation] The surface elastic modulus was measured and the adhesiveness was evaluated by the following method for the substrates with protrusions produced in Inventive Examples 1 to 8 and Comparative Example 1. The results are shown in Table 1.

[0059] (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 triangular wave-shaped protrusions is shown in Table 1 below. Measurements were performed at room temperature (25°C).

[0060] (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).

[0061] [Table 1]

[0062] The results in Table 1 confirm that the protrusion-equipped substrates obtained in Invention Examples 1 to 8, in which the average pitches L11, L12 and average height D3 of the protrusions were within the ranges of the present invention, had higher adhesive strength than the protrusion-equipped substrate obtained in Comparative Example 1, and were useful as bonded structures. The protrusion-equipped substrates obtained in Invention Examples 1 to 8 had high adhesive strength because the surface elastic modulus was low and the protrusions deformed greatly when pressure was applied with the adherend.

[0063] The substrate with protrusions obtained in Comparative Example 1, in which the average pitches L11, L12 and average height D13 were smaller than the ranges of the present invention, did not adhere even though D13 / L11 was the same as in Invention Examples 1 to 8. This is because the average height D13 became too small, resulting in a high surface elastic modulus.

[0064] [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.

[0065] [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.

[0066] [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.

[0067] [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.

[0068] [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.

[0069] [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.

[0070] [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.

[0071] [evaluation] The surface elastic modulus was measured and the adhesiveness was evaluated by the above-mentioned method for the substrates with protrusions produced in Inventive Examples 9 to 19 and Comparative Example 2. The results are shown in Table 2.

[0072] [Table 2]

[0073] The results in Table 2 confirm that the protrusion-equipped substrates obtained in Invention Examples 9 to 19, in which the average pitches L21, L22 and average height D23 of the protrusions were within the ranges of the present invention, had higher adhesive strength than the protrusion-equipped substrate obtained in Comparative Example 2, and are useful as bonded structures. The protrusion-equipped substrates obtained in Invention Examples 9 to 19 had high adhesive strength because they had a low surface elastic modulus and the protrusions deformed greatly when pressed with an adherend. In particular, the protrusion-equipped substrates obtained in Invention Examples 13 to 19, which had body portions, had high adhesive strength. This is because the presence of body portions made the protrusions more susceptible to deformation.

[0074] The substrate with protrusions obtained in Comparative Example 1, in which the average pitches L21, L22 and average height D23 were smaller than the ranges of the present invention, did not adhere even though D23 / L21 was the same as in Invention Examples 9 to 12. This is because the average height D23 became too small, resulting in a high surface elastic modulus. [Industrial Applicability]

[0075] The bonded structure of this embodiment has high heat resistance and high adhesive strength, and can be used as a structure for bonding and temporary fixation. The bonded structure of this embodiment is particularly suitable for use in fields such as aerospace, semiconductors, and medicine, where the environment is subject to large changes and little contamination by impurities is required. [Explanation of symbols]

[0076] 10 Adhesive structure 11 Base 12 Protrusion 13 protrusions 14 Point 15 Top 16a, 16b, 16c, 16d sloped surface 17 Torso 18 bottom 20 Adhesive structure 20 Adhesive structure 21 Base 22 Protrusion 23 Protrusion 24 Point 25 Vertex 26a, 26b, 26c, 26d sloped surface 27 Torso 28 bottom 30 probe

Claims

1. An adhesive structure for adhesively holding an adherend, comprising: a base body; and a protrusion portion having a plurality of protrusions provided on at least a part of the surface of the base body, the protrusions are made of an inorganic material, The plurality of protrusions are periodically arranged in a first direction and a second direction intersecting the first direction, The protrusion has a pointed portion with a sharp tip, the average pitch of the protrusions in the first direction is in the range of 100 nm or more and 1500 nm or less, An adhesive structure in which the average pitch of the protrusions in the second direction is in the range of 100 nm or more and 1500 nm or less.

2. The bonded structure according to claim 1 , wherein the average height of the protrusions is 100 nm or more.

3. 3. The bonded structure according to claim 1, wherein the pointed portion of the projection has a shape having inclined surfaces inclined in opposite directions from the apex, or a quadrangular pyramid shape.

4. The adhesive structure according to claim 1 or 2, wherein the protrusion has the pointed portion and a body portion extending from the pointed portion toward the substrate.

5. 5. The adhesive structure according to claim 1, wherein the ratio of the average height of the protrusions to the longer of the average pitch of the protrusions in the first direction and the average pitch of the protrusions in the second direction is in the range of 0.7 or more and 10 or less.

6. the average pitch of the protrusions in the first direction is 500 nm or less, The adhesive structure according to claim 1 , wherein the average pitch of the protrusions in the second direction is 500 nm or less.

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

8. 8. The bonded structure according to claim 7, wherein the metal comprises any one of copper, copper alloy, aluminum, aluminum alloy, and NiP alloy.

9. Using a nanoindenter, a spherical indenter with a diameter of 40 μm was pressed into the protrusion to a depth of at least 10 nm or 20 nm, and the adhesive strength was 35 N / cm ２ The bonded structure according to any one of claims 1 to 8.

Images