Adhesive structure

Abstract

An adhesive structure according to the present invention is characterized in that a tube array structure (20) formed by erecting a plurality of tube bodies (21) formed from a metal oxide is formed on at least a portion of the surface of a base material that comprises an inorganic material. The adhesive structure can be stably used even in high-temperature environments and clean environments and makes it possible to achieve sufficient adhesive force. The metal oxide is preferably an aluminum oxide or a titanium oxide. The tube bodies (21) preferably have an average outer diameter D of at least 40 nm and an average height H of at least 300 nm.

Description

Adhesive structure

[0001] This application claims priority from Japanese Patent Application No. 2023-149147, filed on September 14, 2023, the contents of which are incorporated herein by reference.

[0002] For example, in semiconductor manufacturing equipment, if particles or the like are present on the holding surface of a semiconductor wafer, the flatness of the holding surface is impaired, causing manufacturing defects and reducing yield. Conventionally, as a method for removing particles, as shown in Patent Document 1, for example, a substrate to which an adhesive substance is adhered is used as a cleaning wafer, and this cleaning wafer is transported empty to remove particles from the transport system and processing unit.

[0003] Furthermore, in gripping members that grip an object and transport members that transport an object, adhesive structures having adhesive properties are disposed on the portions that come into contact with the object in order to stably fix the object, as shown in Patent Documents 2 and 3, for example. Furthermore, when handling an object, adhesive structures are used to temporarily fix the object and prevent it from shifting position, as shown in Patent Document 4, for example. Here, the adhesive structure is required to have sufficient frictional force between itself and the object, and therefore is usually made of an organic material such as rubber, which is a viscoelastic body.

[0004] Japanese Patent Publication No. 2009-117440 (A) Japanese Patent Publication No. 2018-094704 (A) International Publication No. WO2009 / 005027 (A) Japanese Patent Publication No. 2009-168860 (A)

[0005] However, the method disclosed in Patent Document 1 requires temporarily halting the operation of semiconductor manufacturing equipment or lowering the environmental temperature to 400°C or below when removing particles, resulting in a decrease in productivity due to downtime. Furthermore, organic materials such as rubber have insufficient heat resistance, making them unable to be used stably in high-temperature environments. Furthermore, there is a problem that they cannot be used in clean environments due to the risk of contamination by the organic materials. Therefore, adhesive structures made of organic materials could not be applied to, for example, semiconductor manufacturing process applications, aerospace applications, and robot applications.

[0006] Here, industrial materials that constitute various components can be broadly divided into organic materials such as resins and rubber, and inorganic materials such as ceramics and metals. As mentioned above, organic materials have excellent flexibility but poor heat resistance. In contrast, inorganic materials have excellent heat resistance but poor flexibility. Thus, when it comes to industrial materials, a trade-off in properties occurs depending on the material selected.

[0007] Therefore, when the adhesive structure is made of inorganic materials, it has excellent heat resistance and reduces contamination problems, but there is a risk that it will not be possible to obtain sufficient adhesive strength, and it will not be possible to adequately fix the object or to adsorb and remove particles.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an adhesive structure that can be used stably even in high-temperature environments and clean environments, and that can obtain sufficient adhesive strength.

[0009] In order to solve this problem, the inventors conducted extensive research and discovered that by forming a special structure on the surface of a substrate made of an inorganic material such as ceramic or metal, sufficient adhesive strength can be imparted to the surface, making it possible to use the substrate as an adhesive structure.

[0010] The present invention has been made based on the above-mentioned findings, and the adhesive structure of aspect 1 of the present invention is characterized in that a tube array structure in which a plurality of tube bodies made of metal oxide are erected is formed on at least a part of the surface of a substrate made of an inorganic material.

[0011] The bonded structure of aspect 1 of the present invention is made of an inorganic material such as ceramics or metal, and therefore has excellent heat resistance and can sufficiently suppress contamination problems. Furthermore, a tube array structure in which a plurality of tube bodies made of metal oxide are erected is formed on at least a portion of the surface of the substrate, making it possible to impart sufficient adhesive strength to the surface of the substrate. Therefore, it can be used stably even in high-temperature environments and clean environments, and sufficient adhesive strength can be obtained. In other words, the bonded structure of aspect 1 of the present invention can be used as an anti-slip member or a foreign matter adsorption member that can be used stably even in high-temperature environments and clean environments.

[0012] A second aspect of the present invention is characterized in that, in the bonded structure of the first aspect, the metal oxide is aluminum oxide or titanium oxide. According to the bonded structure of the second aspect of the present invention, the tube bodies constituting the tube array structure are made of aluminum oxide or titanium oxide, so that sufficient adhesive strength can be obtained, heat resistance is excellent, and contamination problems can be sufficiently suppressed.

[0013] Aspect 3 of the present invention is characterized in that, in the bonded structure of Aspect 1 or Aspect 2, the tube bodies have an average outer diameter D of 40 nm or more and an average height H of 300 nm or more. According to the bonded structure of Aspect 3 of the present invention, the tube bodies have an average outer diameter D of 40 nm or more and an average height H of 300 nm or more, so that a tube array structure formed from these tube bodies can reliably obtain sufficient adhesive strength.

[0014] A fourth aspect of the present invention is characterized in that the average inner diameter of the tube bodies is 10 nm or more in the bonded structure of any one of aspects 1 to 3. According to the bonded structure of the fourth aspect of the present invention, since the average inner diameter of the tube bodies is 10 nm or more, a tube array structure formed from these tube bodies can reliably obtain sufficient adhesive strength.

[0015] Aspect 5 of the present invention is characterized in that, in the bonded structure of any one of Aspects 1 to 4, the aspect ratio H / D calculated from the average outer diameter D and average height H of the tube bodies is 3 or more and 30 or less. According to the bonded structure of Aspect 5 of the present invention, the aspect ratio H / D calculated from the average outer diameter D and average height H of the tube bodies is 3 or more and 30 or less, so that a tube array structure composed of these tube bodies can reliably obtain sufficient adhesive strength.

[0016] A sixth aspect of the present invention is characterized in that, in the bonded structure of any one of aspects 1 to 5, the occupancy rate of the tube array structure on the surface is 30% or more. According to the bonded structure of the sixth aspect of the present invention, the occupancy rate of the tube array structure on the surface is 30% or more, so that sufficient adhesive strength can be reliably obtained.

[0017] A seventh aspect of the present invention is the bonded structure of any one of Aspects 1 to 6, characterized in that the static friction coefficient of the surface of the substrate with respect to silicon is 0.30 or more. According to the bonded structure of Aspect 7 of the present invention, since the static friction coefficient of the surface of the substrate with respect to silicon is 0.30 or more, the target member can be reliably fixed.

[0018] Aspect 8 of the present invention is characterized in that the adsorption rate of particles having a particle diameter of 1 μm or more and 30 μm or less is 5% or more in the bonded structure of any one of Aspects 1 to 7. According to the bonded structure of Aspect 8 of the present invention, the adsorption rate of particles having a particle diameter of 1 μm or more and 30 μm or less is 5% or more, so that particles can be reliably removed by adhesion.

[0019] According to the present invention, it is possible to provide an adhesive structure that can be stably used even in high-temperature environments and clean environments and that can obtain sufficient adhesive strength.

[0020] FIG. 1 is a schematic explanatory diagram of a bonded structure according to an embodiment of the present invention. FIG. 2 is an observation photograph of a tube array structure in a bonded structure according to an embodiment of the present invention. FIG. 3 is an explanatory diagram of a tube body. FIG. 4 is an explanatory diagram showing a method for measuring a static friction coefficient. FIG. 5 is an explanatory diagram showing a method for measuring a particle adsorption rate. FIG. 6 is a flow chart showing a method for manufacturing a bonded structure according to an embodiment of the present invention. FIG. 7 is an explanatory diagram showing a method for measuring a static friction coefficient in an example. FIG. 8 is an explanatory diagram showing a method for measuring a static friction coefficient in an example.

[0021] Hereinafter, a bonded structure 10 according to one embodiment of the present invention will be described with reference to the accompanying drawings. The bonded structure 10 according to this embodiment is used to temporarily fix an object or to adsorb and remove particles present on the surface of a substrate or the like in gripping devices, conveying devices, manufacturing devices, and the like used in high-temperature or clean environments in the aerospace, semiconductor manufacturing process, medical, and other fields.

[0022] The bonded structure 10 of this embodiment has a substrate 11 made of an inorganic material such as ceramics or metal, and a tube array structure 20 in which a plurality of tube bodies 21 made of metal oxide are erected is formed on at least a portion of the surface of the substrate 11. There are no particular restrictions on the shape or size of the substrate 11, but in this embodiment, as shown in Fig. 1, the substrate 11 is plate-shaped and has a thickness in the range of, for example, 10 µm to 10 cm.

[0023] Here, examples of inorganic materials constituting the substrate 11 include metal, ceramics, silicon, and glass. The inorganic material constituting the substrate 11 preferably has a melting point of 100°C or higher and a decomposition temperature of 100°C or higher, more preferably a melting point of 300°C or higher and a decomposition temperature of 300°C or higher, and even more preferably a melting point of 500°C or higher and a decomposition temperature of 500°C or higher.

[0024] The metal constituting the substrate 11 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, copper, titanium, tungsten, and magnesium. Examples of alloys include aluminum alloys, NiP, stainless steel, and copper alloys. Ceramics constituting the substrate 11 can be oxides, nitrides, and carbides. Examples of ceramics include aluminum oxide (alumina), titanium oxide, and quartz. The inorganic material constituting the substrate 11 is preferably a metal, and more preferably contains any of copper, copper alloys, aluminum, aluminum alloys, and NiP alloys.

[0025] 2 and 3, the tube array structure 20 formed on the surface of the substrate 11 has a structure in which a plurality of tube bodies 21 made of a metal oxide are arranged upright. Here, the metal oxide constituting the tube bodies 21 is preferably, for example, aluminum oxide or titanium oxide. In this embodiment, the substrate 11 is made of titanium, and the tube bodies 21 are made of titanium oxide.

[0026] Here, the tube bodies 21 preferably have an average height of 300 nm or more. The height of the tube bodies 21 can be measured from a cross-sectional SEM photograph of the tube array structure 20 taken with an SEM (scanning electron microscope). The average height H of the tube bodies 21 is more preferably 400 nm or more, and even more preferably 500 nm or more. On the other hand, the average height H of the tube bodies 21 is preferably 5000 nm or less, and even more preferably 3000 nm or less.

[0027] The tube body 21 preferably has an average outer diameter D of 40 nm or more. The outer diameter of the tube body 21 can be measured from a cross-sectional SEM photograph of the tube array structure 20 taken with an SEM (scanning electron microscope). The lower limit of the average outer diameter D of the tube body 21 is more preferably 50 nm or more, and even more preferably 70 nm or more. On the other hand, the average outer diameter D of the tube body 21 is preferably 700 nm or less, and even more preferably 500 nm or less.

[0028] The tube body 21 preferably has an average inner diameter d of 10 nm or more. The inner diameter of the tube body 21 can be measured from a cross-sectional SEM photograph of the tube array structure 20 taken with an SEM (scanning electron microscope). The average inner diameter d of the tube body 21 is more preferably 12 nm or more, and even more preferably 14 nm or more. On the other hand, the average inner diameter d of the tube body 21 is preferably 500 nm or less, and even more preferably 300 nm or less.

[0029] Furthermore, the aspect ratio H / D of the tube body 21, calculated from the average outer diameter D and average height H of the tube body 21, is preferably in the range of 3 to 30. The aspect ratio of the tube body 21 can be measured from a cross-sectional SEM photograph of the tube array structure 20 taken with an SEM (scanning electron microscope). The aspect ratio H / D of the tube body 21 is preferably 4 or more, and more preferably 5 or more. On the other hand, the aspect ratio H / D of the tube body 21 is preferably 25 or less, and more preferably 20 or less.

[0030] In the bonded structure 10 of this embodiment, the area ratio (occupancy ratio) of the tube array structure 20 on the surface (bonding surface) is preferably 30% or more. In the bonded structure 10 shown in FIG. 1 , the tube array structure 20 is formed on approximately 70% of the surface of the substrate 11. The area ratio of the tube array structure 20 on the surface of the substrate 11 is preferably 50% or more, and more preferably 70% or more. The area ratio of the tube array structure 20 on the surface of the substrate 11 is 100% or less.

[0031] In the adhesive structure 10 of this embodiment, the static friction coefficient μ on the surface of the substrate 11 on which the tube array structure 20 is formed is set to 0.30 or more. The static friction coefficient μ on the surface of the substrate 11 is preferably 0.35 or more, and more preferably 0.40 or more. There is no particular upper limit to the static friction coefficient μ, but in reality, the static friction coefficient μ is 10 or less. Here, the static friction coefficient μ on the surface of the substrate 11 can be calculated using the following formulas (1) to (4) and FIG. 4. Formula (1) is the formula for the maximum static friction coefficient. In FIG. 4, m is the mass of the object, g is the gravitational acceleration, F ０ is the maximum static friction force, and N is the normal force. Specifically, when the angle at which an object starts to slide is θ, the coefficient of static friction is expressed as μ = tan θ. Therefore, the coefficient of static friction μ can be obtained by substituting the angle θ at which an object starts to slide into equation (4).

[0032] In addition, in the adhesive structure 10 of this embodiment, the adsorption rate of particles having a particle diameter of 1 μm to 30 μm is set to 5% or more. Although not particularly limited, the adsorption rate of particles having a particle diameter of 1 μm to 30 μm may be 7% or more, or 10% or more. Furthermore, the adsorption rate of particles having a particle diameter of 1 μm to 30 μm may be 100% or less, 70% or less, or 50% or less. Here, the particle adsorption rate can be calculated using the procedure shown in FIG. 5 . That is, a liquid L containing particles P (PSL particles: polystyrene latex particles) having a particle diameter of 1 μm to 30 μm is dropped onto the surface of an object O (e.g., a wafer) to disperse the particles P. The surface of the adhesive structure 10 on which the tube array structure is formed is brought into contact with the object O to adsorb the particles P. The number of particles in the contact area of ​​the adhesive structure 10 on the surface of the object O before and after contact is counted using a particle counter, and the adsorption rate of the particles P is calculated from the reduction in the number of particles.

[0033] Next, an example of a method for manufacturing the bonded structure 10 of this embodiment will be described. In the bonded structure 10 of this embodiment, as described above, the substrate 11 is made of titanium, and the tube body 21 is made of titanium oxide. This embodiment includes a chemical polishing step S01 and an anodizing step S02, as shown in the flow diagram of FIG.

[0034] In the chemical polishing step S01, the surface of the substrate 11 made of an inorganic material (titanium) is chemically polished to smooth the surface. The substrate 11 is immersed in a chemical polishing solution appropriate for the material of the substrate 11, and chemical polishing is performed under conditions of a temperature of 20° C. to 50° C. and a holding time of 1 minute to 10 minutes.

[0035] In the anodizing step S02, the surface of the substrate 11 polished in the chemical polishing step S01 is anodized. The anodizing results in a porous structure in which holes are formed on the surface of the substrate 11, and the wall surfaces are separated and independent to form a tube array structure 20 in which a plurality of tube bodies 21 are erected.

[0036] The treatment liquid used in the anodization may be, for example, a mixture of an ammonium fluoride aqueous solution and an ethylene glycol aqueous solution, etc. The anodization is carried out under the conditions of a voltage of 5 V to 100 V, a temperature of 10° C. to 30° C., and a holding time of 5 minutes to 60 minutes.

[0037] The bonded structure 10 of this embodiment is manufactured by the above-described steps.

[0038] The bonded structure 10 of this embodiment, configured as described above, is made of inorganic materials such as ceramics and metals, and therefore has excellent heat resistance and can sufficiently suppress contamination problems. Furthermore, the tube array structure 20, in which a plurality of tube bodies 21 made of metal oxide are erected on at least a portion of the surface of the substrate 11, can provide sufficient adhesive strength to the surface of the substrate 11. Therefore, the bonded structure 10 can be used stably even in high-temperature and clean environments, and sufficient adhesive strength can be obtained.

[0039] In the adhesive structure 10 of this embodiment, if the metal oxide constituting the tube body 21 is composed of aluminum oxide or titanium oxide, an appropriate tube array structure 20 can be formed to obtain sufficient adhesive strength.

[0040] In the adhesive structure 10 of this embodiment, if the average outer diameter of the tube bodies 21 constituting the tube array structure 20 is 40 nm or more and the average height is 300 nm or more, the tube array structure 20 composed of these tube bodies 21 can reliably obtain sufficient adhesive strength.

[0041] In the bonded structure 10 of this embodiment, when the average inner diameter of the tube bodies 21 is 10 nm or more, the tube array structure 20 formed with these tube bodies 21 can reliably obtain sufficient adhesive strength.

[0042] In the adhesive structure 10 of this embodiment, when the aspect ratio H / D calculated from the average outer diameter D and average height H of the tube body 21 is 3 or more and 30 or less, the tube array structure formed by this tube body 21 can reliably obtain sufficient adhesive strength.

[0043] In the bonded structure 10 of this embodiment, when the area ratio of the tube array structure 20 on the surface of the substrate 11 is 30% or more, the tube array structure 20 can reliably obtain sufficient adhesive strength.

[0044] In the bonded structure 10 of this embodiment, if the static friction coefficient of the surface of the substrate 11 against silicon is 0.30 or more, the bonded structure 10 can be used to reliably fix the target member.

[0045] In the adhesive structure 10 of this embodiment, when the adsorption rate of particles having a particle diameter of 1 μm or more and 30 μm or less is 5% or more, particles present on the surface of the object can be reliably adhered and removed.

[0046] Although the adhesive structure according to the embodiment of the present invention has been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the technical spirit of the invention. For example, in the present embodiment, the substrate is titanium and the tube bodies constituting the tube array structure are formed of titanium oxide, but the present invention is not limited thereto and the substrate may be made of another inorganic material, or the tube bodies may be made of another metal oxide such as aluminum oxide.

[0047] The results of confirmation experiments conducted to confirm the effects of the present invention will be described below.

[0048] First, a substrate (length: 7 mm, width: 7 mm, thickness: 1 mm) made of the inorganic material shown in Table 1 was prepared. The prepared substrate was chemically polished using a chemical polishing solution (TCP-80 manufactured by Mitsubishi Gas Chemical Co., Inc.) at 30°C for 5 minutes. The chemically polished sample was polished with 0.38 mass% NH ４ F and 10 mass% H ２ Anodization was performed by constant voltage electrolysis for 20 minutes in an ethylene glycol aqueous solution containing O at a bath temperature of 20°C under the voltage conditions shown in Table 1. This produced an adhesive structure having a tube array structure. The average inner diameter, average outer diameter, average height, and aspect ratio H / D of the tube bodies constituting the tube array structure were as shown in Table 1.

[0049] (Static Friction Coefficient) The static friction coefficient of the surface on which the tube array structure was formed of the obtained bonded structure was measured. A 300 mm circular silicon wafer S was prepared. The surface roughness Ra of the silicon wafer S was set to 0.14 nm. As shown in Figures 7A to 7C, four bonded structures 10 were arranged at 90° intervals in the circumferential direction at radial positions 140 mm from the center of the silicon wafer S, and placed on a fixed plate Q.

[0050] The adhesive structure 10 was placed so that the surface on which the tube array structure was formed faced the silicon wafer S. In addition, by using a silicon wafer with a mass of 128 g, the load in the stacking direction was 43 g / cm ２The fixing plate Q was then tilted, and the angle θ at which the silicon wafer S slid down was measured, and the static friction coefficient was calculated. The results are shown in Table 1.

[0051] (Particle adsorption rate) A 300 mm disk-shaped silicon wafer S was prepared. A liquid containing standard particles with an average particle diameter of 30 μm was dropped onto the surface of this silicon wafer to disperse the standard particles. In this state, the number of particles present in the area on the surface of the silicon wafer where the adhesive structure was to be laminated was measured using a particle counter. Next, the adhesive structure and the silicon wafer were laminated so that the surface of the adhesive structure on which the tube array structure was formed came into contact with the surface of the silicon wafer S on which the standard particles (polystyrene latex particles: 30 μm) were dispersed. After allowing them to contact for 30 seconds, the adhesive structure was removed.

[0052] The number of particles present on the surface of the silicon wafer in the region where the adhesive structure was laminated was measured using a particle counter. The particle adsorption rate was calculated from the number of particles before and after laminating the adhesive structure. The results are shown in Table 1.

[0053]

[0054] In Comparative Examples 1 and 2, the tube array structure was not formed, and the static friction coefficient was low at 0.19 in Comparative Example 1 and 0.20 in Comparative Example 2, resulting in insufficient surface friction and making it difficult to firmly fix the object. In addition, the particle adsorption rate was 0.0%, meaning that no effect of removing particles was observed.

[0055] In contrast, in Examples 1 to 8 of the present invention, a tube array structure was formed, and the static friction coefficient of the surface was 0.30 or more, confirming that the friction force was high and the object could be sufficiently fixed. In addition, the particle adsorption rate was 5% or more, confirming that particles present on the surface of the object could be removed.

[0056] From the above, it was confirmed that the present invention can provide an adhesive structure that can be used stably even in high-temperature environments and clean environments and that can obtain sufficient adhesive strength.

[0057] According to the present invention, it is possible to provide an adhesive structure that can be stably used even in high-temperature environments and clean environments and that can obtain sufficient adhesive strength.

[0058] REFERENCE SIGNS LIST 10 Adhesive structure 11 Substrate 20 Tube array structure 21 Tube body L Liquid containing particles with a particle diameter of 1 μm or more and 30 μm or less O Object P Particles

Claims

1. An adhesive structure characterized in that a tube array structure in which a plurality of tube bodies made of a metal oxide are arranged upright on at least a portion of the surface of a substrate made of an inorganic material is formed.

2. The bonded structure according to claim 1, wherein the metal oxide is aluminum oxide or titanium oxide.

3. The adhesive structure according to claim 1 or 2, characterized in that the tube body has an average outer diameter D of 40 nm or more and an average height H of 300 nm or more.

4. The adhesive structure according to claim 1 or 2, characterized in that the average inner diameter of the tube body is 10 nm or more.

5. The bonded structure according to claim 3, characterized in that the aspect ratio H / D calculated from the average outer diameter D and the average height H of the tube body is 3 or more and 30 or less.

6. The adhesive structure according to claim 1 or 2, characterized in that the occupancy rate of the area of ​​the surface of the tube array structure is 30% or more.

7. The bonded structure according to claim 1 or 2, characterized in that the surface of the substrate has a static friction coefficient with respect to silicon of 0.30 or more.

8. The bonded structure according to claim 1 or 2, characterized in that the adsorption rate of particles having a particle diameter of 1 μm or more and 30 μm or less is 5% or more.

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