Structure, method for manufacturing the structure, and processing apparatus

Abstract

To provide a structure that has better properties as a material for a frame of a processing device and the like, a method for manufacturing the structure, and a processing device using the structure.SOLUTION: A structure (CFRP structure) 10 comprises: a laminate (CFRP member) 11 which has carbon fiber as a main component; and metal foils 12a, 12b which are respectively heat-pressed on a pair of surfaces 11a, 11b opposing to each other in a lamination direction of the laminate 11 to be integrated, and have metal as a main component. The thickness of the metal foils 12a, 12b is thinner than the thickness of the laminate 11.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a structure containing carbon fiber, a method for manufacturing the structure, and a processing apparatus using the structure.

Background Art

[0002] Conventionally, in processing apparatuses such as exposure apparatuses and laser processing apparatuses, a frame for supporting constituent members has been made of a metal such as iron. In the case of an exposure apparatus, the frame supports constituent members such as a light irradiation unit, a mask stage, a projection lens, and a work (substrate) stage. Also, in the case of a laser processing machine, the frame supports constituent members such as a laser device and a work stage. In such a processing apparatus, when a change in ambient temperature or heat generation of the apparatus itself occurs, the metal frame expands and contracts due to thermal expansion. When the frame expands and contracts, the positions of the above-described constituent members supported by the frame change, and there is a risk that the processing accuracy may decrease. Therefore, as the material of the frame of the processing apparatus, it is desirable to use a material having as low a coefficient of thermal expansion as possible.

[0003] Also, the frame of the processing apparatus requires high rigidity (elastic modulus). As described above, in a processing apparatus, the frame supports the work stage. The work stage frequently repeats sequential movement, for example, in step-and-repeat exposure that divides a region of a substrate and in drilling for forming a large number of through-holes in the substrate. Therefore, when the work stage is supported by a frame having low rigidity, the frame vibrates greatly due to the sequential movement of the work stage, and the time until the vibration of the frame stops, that is, the time until the next exposure or processing is performed becomes long. As a result, the processing time of the work becomes long, and the productivity of the apparatus decreases. Furthermore, when the rigidity of the frame is low, it is vulnerable to external vibration and is likely to sway. Therefore, it can also be a cause of poor processing accuracy.

[0004] Furthermore, an important requirement for frame components is low density, so that even large devices remain relatively lightweight. Increased weight would necessitate reinforcing the factory floor where the device is installed, leading to higher overall costs. Thus, it is desirable for the frame of the processing equipment to have high rigidity (elastic modulus) and low thermal expansion coefficient and density. Carbon fiber reinforced plastic (CFRP) is a material that satisfies these conditions. For example, Patent Document 1 discloses the use of CFRP in automobile frames and the like. This Patent Document 1 discloses how to reinforce the structural members of an automobile while suppressing weight increase by bonding a CFRP reinforcing material to the surface of a metal member. [Prior art documents] [Patent Documents]

[0005] [Patent Document 2] Japanese Patent Publication No. 2017-61068 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The technology described in Patent Document 1 above only discloses the use of CFRP as a reinforcing material for automobile frames, and does not consider suitable materials for the frames of processing equipment. While it is conceivable to use CFRP alone as the frame for processing equipment, in recent years, processing equipment has been required to have extremely high processing accuracy, and it is necessary to use a structure with even better properties than CFRP alone as the material for the frame. However, even if one were to combine CFRP with other materials such as metal to improve its properties, it is not clear how to combine them effectively. Furthermore, CFRP has the characteristic of absorbing moisture from the environment in which it is used, causing it to expand and undergo dimensional deformation. In addition, because the penetration and diffusion of moisture into the interior of CFRP proceeds slowly, the distribution of moisture concentration inside the CFRP is non-uniform, and the condition changes gradually, which can lead to various complex deformations such as deterioration of surface roughness and torsional deformation.

[0007] Therefore, the present invention aims to provide a structure having better properties as a material for the frame of a processing apparatus, a method for manufacturing the structure, and a processing apparatus using the structure. [Means for solving the problem]

[0008] To solve the above problems, one aspect of the structure according to the present invention comprises a laminate mainly composed of carbon fibers and a metal foil mainly composed of metal, which is heat-pressed and integrated onto a pair of surfaces of the laminate that are opposite to each other in the lamination direction, wherein the thickness of the metal foil is thinner than the thickness of the laminate. Thus, a structure combining a laminate primarily composed of carbon fibers with a metal foil thinner than the laminate can be made into a structure with a low coefficient of thermal expansion and excellent moisture resistance, and can exhibit less dimensional deformation due to temperature and humidity changes than CFRP alone. Furthermore, it can be made into a structure with higher rigidity, lower density, and higher specific stiffness than metal. In other words, it can be made into a structure with even better properties than CFRP alone, for use as a material for processing equipment frames, etc.

[0009] Furthermore, the metal foil is heat-pressed onto the surface of the laminate, directly bonding it to the laminate without the use of adhesive. Therefore, it is possible to effectively suppress moisture absorption by the laminate via the adhesive, or absorption of moisture that penetrates through the interface with the adhesive, thereby suppressing a decrease in moisture resistance. Furthermore, the thickness of the metal foil is thinner than the thickness of the laminate. Therefore, it is possible to create a structure that does not impair the characteristics of carbon fiber by suppressing increases in weight and thermal expansion coefficient.

[0010] Furthermore, in the above-described structure, the pair of surfaces of the laminate may be formed by molding a prepreg made by impregnating carbon fibers with resin. In this case, the prepreg acts as an adhesive, allowing for easy and proper bonding between the laminate and the metal foil. Because carbon fibers are present in the prepreg, it does not easily absorb moisture from the sides, unlike general adhesives. Therefore, moisture absorption at the interface between the laminate and the metal foil can be effectively suppressed. Furthermore, in the above structure, the metal foil may be bonded to the resin over the entire surface of each of the pair of surfaces of the laminate. In this case, the metal foil is stably bonded to the laminate.

[0011] Furthermore, in the above-described structure, the laminate may be a carbon fiber reinforced plastic member. In this case, the structure can be made that possesses the characteristics of carbon fiber reinforced plastic, such as high specific stiffness, low density and coefficient of thermal expansion, and excellent moisture resistance.

[0012] Furthermore, in the above structure, the metal foil may be heat-pressed onto the pair of surfaces of the laminate under reduced pressure to form a single integrated structure. In this case, the laminate and the metal foil can be laminated and integrated without introducing air bubbles at the interface.

[0013] Furthermore, in the above structure, the metal foil may be made of copper, aluminum, titanium, or stainless steel. In this case, the moisture-resistant effect of the structure can be properly achieved.

[0014] Furthermore, in the above-described structure, the thickness of the metal foil may be on the order of microns. In this case, the occurrence of pinholes and other defects in the metal foil can be suppressed, and the moisture resistance can be properly maintained.

[0015] Furthermore, one embodiment of the structure according to the present invention comprises a carbon fiber reinforced plastic member formed by laminating prepregs made of carbon fibers impregnated with resin, and a metal foil mainly composed of metal bonded to the resin over its entire surface on a pair of surfaces of the carbon fiber reinforced plastic member that are opposite to each other in the lamination direction of the prepregs, wherein the thickness of the metal foil is thinner than the thickness of the carbon fiber reinforced plastic member. Thus, a structure combining a laminate primarily composed of carbon fibers with a metal foil thinner than the laminate can be made into a structure with a low coefficient of thermal expansion and excellent moisture resistance, and can exhibit less dimensional deformation due to temperature and humidity changes than CFRP alone. Furthermore, it can be made into a structure with higher rigidity, lower density, and higher specific stiffness than metal. In other words, it can be made into a structure with even better properties than CFRP alone, for use as a material for processing equipment frames, etc.

[0016] Furthermore, the metal foil is bonded to the resin constituting the prepreg on the surface of the carbon fiber reinforced plastic component. In other words, it is directly bonded to the carbon fiber reinforced plastic component without the use of adhesives. Therefore, it is possible to appropriately suppress moisture absorption by the laminate via adhesives, or absorption of moisture that penetrates through the interface with the adhesive, thereby suppressing a decrease in moisture resistance. Furthermore, the thickness of the metal foil is thinner than that of the carbon fiber reinforced plastic component. Therefore, it is possible to create a structure that does not impair the characteristics of carbon fiber reinforced plastic by suppressing increases in weight and thermal expansion coefficient.

[0017] Furthermore, one embodiment of the method for manufacturing a structure according to the present invention includes a first step of preparing a laminate mainly composed of carbon fibers, a second step of preparing a metal foil mainly composed of metal and thinner than the laminate, and a third step of integrating the laminate and the metal foil by placing the metal foils on a pair of surfaces of the laminate that are opposite to each other in the lamination direction and applying pressure while heating. As a result, it is possible to manufacture a structure that has a low coefficient of thermal expansion, excellent moisture resistance, higher rigidity than metal, a low density and a high specific rigidity, and less dimensional deformation due to temperature and humidity changes than a single CFRP. That is, as a material for the frame of a processing apparatus or the like, it is possible to manufacture a structure having better characteristics than a single CFRP.

[0018] Furthermore, one aspect of the processing apparatus according to the present invention is a processing apparatus for processing a workpiece, wherein a frame that supports a constituent member of the processing apparatus includes any of the above structures. In this way, a processing apparatus using, as a material for the frame, a structure in which a laminate mainly composed of carbon fiber and a metal foil thinner than the laminate is combined has less dimensional deformation due to temperature changes, humidity changes, and external factors, and can be a relatively lightweight processing apparatus.

Advantages of the Invention

[0019] According to the present invention, as a material for the frame of a processing apparatus or the like, it is possible to realize a structure having better characteristics, specifically, characteristics excellent in moisture resistance than a single CFRP while suppressing a decrease in rigidity, thermal expansion, and an increase in density.

Brief Description of the Drawings

[0020] [Figure 1] It is a cross-sectional view of the structure in this embodiment. [Figure 2] It is a schematic diagram showing the bonding state of a CFRP member and a metal foil. [Figure 3] It is a cross-sectional view showing another example of the structure of this embodiment. [Figure 4] It is a diagram showing a schematic configuration of an exposure apparatus. [Figure 5] It is a diagram showing a schematic configuration of a laser processing apparatus. [Figure 6] It is a diagram showing the amount of change in the hygroscopic expansion strain of the structure of this embodiment. [Figure 7] It is a diagram showing the amount of change in the hygroscopic expansion strain of the structure of a comparative example. [Modes for carrying out the invention]

[0021] Hereinafter, embodiments of the present invention will be described based on the drawings. (First embodiment) Figure 1 is a cross-sectional view showing the schematic configuration of the structure 10 of the first embodiment. In this embodiment, the structure 10 is a CFRP structure containing carbon fiber reinforced plastic (CFRP). The structure 10 has a configuration in which a first material 11 and second materials 12a and 12b are integrated. Here, the first material 11 is a laminate mainly composed of carbon fibers, and the second materials 12a and 12b are metal foils mainly composed of metal. In this embodiment, the laminate 11 is a carbon fiber reinforced plastic (CFRP) member, and the metal foils 12a and 12b are copper foils. Furthermore, the material of the metal foils 12a and 12b is not limited to copper, but may also be aluminum, titanium, stainless steel (SUS), Super Invar, etc.

[0022] The CFRP member 11 is formed by laminating multiple prepregs 110 and heat-pressing them together to create a single unit. The prepreg 110 is a sheet-like member in which carbon fibers are impregnated with resin while maintaining the directionality of the fibers. The resin constituting the prepreg 110 is, for example, a thermosetting epoxy resin. However, other thermosetting resins such as unsaturated polyester, vinyl ester, phenol, cyanate ester, and polyimide can also be used as the resin constituting the prepreg 110.

[0023] CFRP is formed by stacking multiple prepregs in a mold with the fiber directions of each layer as needed (e.g., 10 layers), heating them under reduced pressure to approximately 120°C to 130°C, and then curing them by pressing (compression). The reason for stacking the prepregs with different fiber directions is to isotropically strengthen the in-plane strength of the prepregs. As a substitute for prepreg, standard CFRP sheets of standard dimensions (for example, 5mm UD (UNI-DIRECTION) material) that can be stocked at low cost can be used. UD material refers to material in which the fibers extend in only one direction.

[0024] The CFRP produced in this way is a material that is lower in density (i.e., lighter) than metal materials such as iron and aluminum, while being high in strength. The CFRP member 11 is a member cut to the desired size from the completed CFRP described above.

[0025] The copper foils 12a and 12b are uniformly integrated onto a pair of surfaces 11a and 11b of the CFRP member 11 that are opposite each other in the lamination direction (up and down direction in Figure 1). Specifically, as shown in Figure 2, the surface 11a of the CFRP member 11 is constructed by molding a prepreg 110 made by impregnating carbon fibers 111 with resin 112, and the copper foil 12a is integrated with the CFRP member 11 by bonding with the resin 112 over its entire surface 11a. The same applies to the copper foil 12b on the surface 11b of the CFRP member 11.

[0026] Furthermore, as shown in Figure 1, the thicknesses D2a and D2b of the copper foils 12a and 12b are set to be thinner than the thickness D1 of the CFRP member 11. Here, "thickness" refers to the thickness of the member in the direction perpendicular to the lamination direction of the CFRP member 11, which is the surface 11a and 11b.

[0027] The following describes an example of a manufacturing method for the structure 10 in this embodiment. First, prepare several sheets (for example, 10 sheets) of prepreg 110 with a thickness of 200 μm. Also, prepare copper foils 12a and 12b, each with a thickness of 20 μm. Note that the thicknesses D2a and D2b of copper foils 12a and 12b may be different. Next, copper foils 12a and 12b are placed over the entire front and back surfaces of a laminate made of 10 layers of prepreg 110. The laminate is then pressurized under reduced pressure (while creating a vacuum) to prevent air bubbles from being introduced at the interface between the prepreg 110 and the copper foils 12a and 12b, and the temperature is raised to 130°C over 1 hour to cure. After being held in this state for 1 hour, it is allowed to cool to room temperature. In this way, copper foils 12a and 12b are heat-pressed and integrated onto both the front and back surfaces of the CFRP member 11, which is formed from 10 layers of prepreg 110, covering the entire surface. The structure 10 is manufactured by removing excess copper foils 12a and 12b by trimming the edges as needed.

[0028] Furthermore, copper foils 12a and 12b can be laminated and integrated onto both the front and back surfaces of a hardened CFRP member via a prepreg 110. For example, a CFRP member is prepared by laminating six layers of 200 μm thick prepreg 110 and curing it using the method described above. Next, two layers of prepreg 110, for example, 200 μm thick, are laminated onto the entire front and back surfaces of the prepared CFRP member. Then, copper foils 12a and 12b are placed on top of each other. To prevent air bubbles from being introduced at the interface between the prepreg 110 and the copper foils 12a and 12b, the material is pressurized under reduced pressure (while creating a vacuum) and heated to 130°C over one hour to cure. After holding it in this state for one hour, it is allowed to cool to room temperature.

[0029] In this case as well, a structure 10 can be manufactured in which copper foils 12a and 12b are heat-pressed and bonded to both the front and back surfaces of a CFRP member 11 formed from 10 layers of prepreg 110, making a unified structure. In either manufacturing method, if copper foils 12a and 12b of the same size as the CFRP member 11 (prepreg 110) are prepared, edge trimming is not necessary.

[0030] Furthermore, as shown in the structure 10A in Figure 3, protective layers 13 can be laminated on the copper foils 12a and 12b to prevent oxidation and contamination of the copper foil surfaces, prevent the generation of wear particles, and so on. Here, the protective layer 13 can be a plastic film such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), or PI (polyimide). Alternatively, nickel plating or tin plating may be used for the protective layer 13.

[0031] The structure 10 in this embodiment can be used, for example, as the frame of a processing apparatus. Here, the processing apparatus includes, for example, an exposure apparatus that exposes patterns such as circuits onto semiconductor substrates or printed circuit boards, and a laser processing apparatus that irradiates a substrate with a laser to perform cutting or drilling. Furthermore, a stage apparatus used as part of the configuration of the exposure apparatus or laser processing apparatus can also be included in the processing apparatus. The stage apparatus is a device that holds and moves a workpiece such as the above-mentioned substrate.

[0032] Figure 4 shows a schematic configuration of the exposure apparatus. The exposure apparatus 200 shown in Figure 4 is a projection exposure apparatus for exposing a workpiece. Here, the workpiece is a silicon workpiece, a printed circuit board, or a glass substrate for a liquid crystal panel, etc., and has a resist film coated on its surface.

[0033] The exposure apparatus 200 includes a light irradiation unit 21, a mask 22, a projection lens 23, a work stage 24, and a frame 25. The light irradiation unit 21 includes a lamp 21a, which is an exposure light source that emits light including ultraviolet light, and a mirror 21b that reflects the light from the lamp 21a. The lamp 21a and the mirror 21b are housed in a lamp housing 21c. Although this description focuses on the case where the light source of the light irradiation unit 21 is the lamp 21a, the light source may also be an LED or a laser.

[0034] The mask 22 has patterns, such as circuit patterns, that are exposed (transferred) onto the workpiece. Exposure light from the light irradiation unit 21 is irradiated onto the workpiece held by the workpiece stage 24 via the mask 22 and the projection lens 23, and the patterns formed on the mask 22 are projected onto the workpiece and exposed. The frame 25 supports the main components of the exposure apparatus 200, such as the light irradiation unit 21, the mask 22, the projection lens 23, and the work stage 24. These main components are held in place by the frame 25, maintaining a horizontal position.

[0035] Figure 5 shows a schematic configuration of a laser processing apparatus. The laser processing apparatus 300 shown in Figure 5 comprises a laser emission unit 31, a work stage 32, and a frame 33. The laser emission unit 31 emits a laser in the direction indicated by the arrow in the figure. The laser beam from the laser emission unit 31 is irradiated onto the workpiece held by the work stage 32, and processing such as cutting and drilling is performed on the workpiece. The frame 33 supports the main components of the laser processing apparatus 300, such as the laser emission unit 31 and the work stage 32. These main components are held in place by the frame 33, maintaining a horizontal position.

[0036] The frame of the processing equipment supports key components that are positioned appropriately. Therefore, if the temperature and humidity of the location where the processing equipment is placed change, and the frame expands or contracts due to thermal or moisture absorption, the position of the key components supported by the frame will change, resulting in a decrease in processing accuracy. Furthermore, it may become impossible to expose the material to the desired position or to perform laser processing (drilling or cutting). To address these issues, the environment within the factory where the processing equipment is installed is controlled to maintain a constant temperature and humidity. Furthermore, individual pieces of equipment are placed in temperature-controlled booths to further manage their temperature and humidity.

[0037] However, even with the environmental control measures described above, it is unavoidable that the processing equipment will generate heat when it is in operation. For example, when the work stage moves, heat is generated from the drive components such as the motor, and in the case of laser processing equipment, heat is generated in the part of the workpiece being processed (the part where holes are drilled or cut). In the case of exposure equipment, when light passes through the projection lens, the light is absorbed by the lens and the lens barrel that holds the lens, causing the projection lens area to generate heat. If the frame is made of a material that easily expands with heat, the frame will expand and contract due to the heat generated by the device itself, as described above, which can reduce processing accuracy. Therefore, the material for the frame of the processing device should be a material with the smallest possible coefficient of thermal expansion, for example, a material with a coefficient of thermal expansion of 1 / 10 or less (preferably 0) that of a metal such as iron.

[0038] Furthermore, even if environmental control measures are in place as described above, if the material of the processing equipment frame contains little moisture and is dry relative to the humidity in the environment, moisture absorption by the frame is unavoidable. The frame is made of a material that easily absorbs moisture. If the moisture content of the material is low, the frame will absorb moisture and expand until it reaches equilibrium, which can reduce processing accuracy. Therefore, for the frame of the processing equipment, a material that exhibits minimal moisture-absorbing expansion strain is desirable.

[0039] Furthermore, the frame of the processing equipment also requires high rigidity (modulus of elasticity). As mentioned above, in processing equipment, the frame supports the work stage. The work stage frequently moves sequentially, for example, in step-and-repeat processes that divide and expose areas of a substrate, or in drilling processes that form numerous through-holes within a substrate. Therefore, if the work stage is supported by a frame with low rigidity, the time it takes for the frame vibration to stop after the stage moves and stops will be longer, increasing the workpiece processing time and reducing the productivity of the equipment. In addition, a frame with low rigidity is weak against external vibrations and prone to shaking, which also contributes to poor machining accuracy. Therefore, the material for the frame of the processing equipment should ideally be a material with the highest possible rigidity, such as a material with higher rigidity than metals like iron.

[0040] Furthermore, it is important that the frame of the processing equipment has a low density so that it remains relatively lightweight, even for large machines. If the weight of the equipment increases, the cost of the equipment will increase, for example, by requiring reinforcement of the factory floor where the equipment is installed. In other words, the materials (structures) that make up the frame of the processing equipment should preferably have the following four characteristics. (1) The coefficient of thermal expansion (CTE) is close to 0 (meaning there is little dimensional deformation due to temperature changes). (2) The moisture-absorbing expansion strain is close to zero (there is little dimensional deformation due to humidity changes). (3) High rigidity, i.e., high modulus of elasticity (less prone to bending, deflection, and distortion, i.e., less dimensional deformation due to external factors). (4) Low density (even large devices are relatively lightweight).

[0041] CFRP possesses characteristics such as high rigidity (elastic modulus) and low thermal expansion coefficient and density. While it is conceivable to use CFRP alone as the frame for processing equipment, CFRP alone has a problem with hygroscopicity. For example, the epoxy resin matrix of CFRP has a moisture absorption rate of about 3%. If the Vf (fiber volume content) of CFRP is 60%, the CFRP as a whole will absorb moisture up to about 1.2%. As a measure against moisture absorption, it is conceivable to use CFRP made from a special prepreg that uses a matrix with a lower moisture absorption rate than epoxy resin, but such prepregs are very expensive and generally difficult to obtain. Furthermore, there are limits to how much moisture absorption can be reduced in CFRP.

[0042] Furthermore, even if CFRP with a relatively low moisture absorption rate is used as the frame of the processing equipment, as described above, CFRP alone cannot reliably prevent moisture absorption in the frame. As mentioned above, CFRP is formed by heat bonding. Therefore, the moisture content inside the CFRP after curing is very low, only a few percent (for example, around 5%). On the other hand, as mentioned above, the environment inside the factory where the processing equipment is installed is controlled to maintain a constant temperature and humidity, and the humidity is, for example, around 50%. Thus, because there is a large humidity gap between the environment in which the processing equipment is installed and the CFRP itself, moisture absorption is unavoidable in frames made solely from CFRP. In recent years, processing equipment has been required to have extremely high processing accuracy, and there is a demand for using structures with even better properties than CFRP alone as the material for the frame.

[0043] The inventors of this invention conducted research on a structure that combines a laminate mainly composed of carbon fiber with a metal foil mainly composed of metal, in order to obtain a structure that can bring out better performance as a frame for processing equipment. The inventors then found that by using copper, aluminum, titanium, SUS, etc. as the material for the metal foil, and sandwiching the laminate with the metal foil and integrating them without using adhesive, it is possible to realize a structure with even better properties than CFRP alone.

[0044] Figure 6 shows the change in moisture-absorbing expansion strain when the structure 10 and a comparison sample in this embodiment are left in a room. In Figure 6, the horizontal axis represents the time of exposure (Hr), and the vertical axis represents the change in moisture-absorbing expansion strain (με). In the figure, curve A represents the change in moisture-absorbing expansion strain of CFRP alone as a comparison sample, and curves a to d represent the change in moisture-absorbing expansion strain of structure 10 in this embodiment. Curve a shows the change in moisture-absorbing expansion strain of structure 10 using copper foil with a thickness of 20 μm as the metal foil, curve b shows the change in moisture-absorbing expansion strain of structure 10 using aluminum foil with a thickness of 11 μm as the metal foil, curve d shows the change in moisture-absorbing expansion strain of structure 10 using titanium foil with a thickness of 5 μm as the metal foil, and curve e shows the change in moisture-absorbing expansion strain of structure 10 using SUS foil with a thickness of 10 μm as the metal foil.

[0045] Here, as the CFRP members constituting the comparison sample and structure 10, we used CFRP members obtained by laminating 10 layers of prepreg so that the carbon fiber elongation direction was aligned in one direction and then curing and molding them. Furthermore, strain measurement was performed by placing a strain gauge in the central layer (e.g., the 5th layer) of the CFRP member in a direction perpendicular to the direction in which the carbon fiber elongation occurs. Furthermore, the strain data was corrected to account for thermal expansion due to temperature fluctuations in the indoor environment, so that only changes due to moisture absorption expansion are obtained.

[0046] As shown by curve A in Figure 6, CFRP alone rapidly absorbs moisture immediately after being left standing, and the moisture-absorbing expansion strain continues to increase. On the other hand, in the structure 10 of this embodiment, as shown by curves a to d, no increase in moisture-absorbing expansion strain was observed. Note that in curves a to d, the moisture-absorbing expansion strain decreases from immediately after being left standing up to about 500 hours, but this is thought to be shrinkage due to physical aging of the resin, and not moisture-absorbing expansion. Thus, it was confirmed that the structure 10 in this embodiment, which uses copper, aluminum, titanium, and SUS as metal foils, has superior moisture resistance compared to CFRP alone.

[0047] In contrast, structures in which CFRP members and metal foil were bonded together with adhesive, and structures in which a thin metal film was formed on the surface of the CFRP member by vapor deposition, did not exhibit moisture resistance. Figure 7 shows the amount of moisture-absorbing expansion strain of the comparison sample under accelerated test conditions at 95% humidity and 45°C. This shows the change This is a diagram. In Figure 7, the horizontal axis represents the standing time (Hr), and the vertical axis represents the change in moisture-absorbing expansion strain (με). In the figure, curve e shows the change in moisture-absorbing expansion strain for a structure in which nano-order vapor-deposited aluminum is formed on the surface of a CFRP member, curve f shows the change in moisture-absorbing expansion strain for a structure in which nano-order vapor-deposited aluminum is formed on the surface of a CFRP member and a protective layer (PET) is provided on top of it, and curve g shows the change in moisture-absorbing expansion strain for a structure in which aluminum tape is attached to the surface of a CFRP member. As shown in Figure 7, an increase in moisture-absorbing expansion strain was observed in all cases.

[0048] If the vapor deposition film thickness is on the nanoscale, pinholes may occur during manufacturing and handling, leading to a decrease in moisture resistance. While a protective layer can suppress the decrease in moisture resistance to some extent, it cannot eliminate moisture-absorbing expansion strain. Furthermore, when a CFRP component and a metal foil are bonded together using an adhesive, even if the thickness of the metal foil is not a problem, moisture-absorbing expansion is likely to occur because the CFRP absorbs moisture absorbed by the adhesive from the sides, or if the adhesion between the CFRP and the adhesive layer is not perfect, moisture penetrates from the interface between the CFRP and the adhesive layer. Therefore, the metal foil needs to be integrated with the CFRP member without the use of adhesive. Furthermore, the thickness of the metal foil is preferably on the order of microns.

[0049] In this embodiment, the structure 10 has a structure in which a CFRP member 11 is sandwiched between metal foils 12a and 12b and heat-pressed to integrate them. In other words, the CFRP member 11 and the metal foils 12a and 12b are integrated without the use of adhesive. Therefore, moisture does not penetrate from the interface between the CFRP member 11 and the metal foils 12a and 12b, resulting in a structure 10 with excellent moisture resistance. Furthermore, by heat-pressing the metal foils 12a and 12b under reduced pressure (for example, in a vacuum), it is possible to prevent air bubbles from being mixed into the interface between the CFRP member 11 and the metal foils 12a and 12b, thereby further improving moisture resistance. In addition, the adhesion between the CFRP member 11 and the metal foils 12a and 12b can also be improved.

[0050] Furthermore, the metal foils 12a and 12b are formed on a pair of surfaces (upper and lower surfaces) of the CFRP member 11 that are opposite each other in the lamination direction. The CFRP member 11 is less likely to absorb moisture from the sides due to the presence of carbon fibers. On the other hand, the upper and lower surfaces of the CFRP member 11 are more likely to absorb moisture than the sides because they have a larger surface area. Therefore, by forming the metal foils 12a and 12b on the upper and lower surfaces of the CFRP member 11, moisture absorption of the CFRP member 11 can be prevented more effectively.

[0051] Furthermore, the thickness of the metal foils 12a and 12b is thinner than the thickness of the CFRP member 11. By using such thin metal foils 12a and 12b, it is possible to maintain the properties of CFRP while improving moisture resistance compared to CFRP alone. In addition, because the metal foils 12a and 12b have high thermal conductivity, even if heat or light is applied to a part of it, it is possible to prevent unevenness in the in-plane temperature and suppress localized deformation.

[0052] Here, the metal foils 12a and 12b can be made of copper, aluminum, titanium, SUS, etc. In any case, an appropriate moisture-preventing effect can be obtained. From the viewpoint of adhesion to the CFRP member 11, copper is the most suitable material for the metal foils 12a and 12b. However, since copper is prone to surface oxidation and easily generates wear particles, it is preferable to provide a PET protective layer or the like on the surface. On the other hand, SUS can be used stably without problems of corrosion or rust.

[0053] As described above, by integrating the CFRP member 11, which is a laminate mainly composed of carbon fibers, with metal foils 12a and 12b, which are mainly composed of metal, without using an adhesive, a lightweight and tough structure 10 can be made that has a small coefficient of thermal expansion, no moisture-absorbing expansion strain, and a specific stiffness higher than that of metal. Furthermore, a CFRP structure 10 formed by laminating multiple prepregs with different fiber directions can achieve relatively high stiffness with an elastic modulus of 40 GPa or more. Furthermore, by utilizing such a structure 10 as the material for the frame of the processing device, it is possible to realize a lightweight processing device that is less susceptible to dimensional deformation due to temperature changes, humidity changes, and external factors.

[0054] (modified version) In the above embodiment, the case in which the structure 10 is used as the frame of a processing device was described, but the invention is not limited to this. The structure 10 has a low coefficient of thermal expansion, high rigidity, is relatively lightweight, has high specific stiffness, and has excellent moisture resistance. Therefore, taking advantage of these characteristics, the structure 10 may be used as a material for components of large devices that require strict dimensional stability in environments where temperature and humidity changes may occur. [Explanation of Symbols]

[0055] 10...Structure (CFRP structure), 11...CFRP member (laminated), 12a,12b...Metal foil, 13...Protective layer, 21...Light irradiation unit, 22...Mask, 23...Projection lens, 24...Work stage, 25...Frame, 31...Laser emission unit, 32...Work stage, 33...Frame, 200...Exposure device (processing device), 300...Laser processing device

Claims

1. The first step is to prepare a laminate mainly composed of carbon fiber, A second step involves preparing a metal foil that is mainly composed of metal and is thinner than the aforementioned laminate, A third step involves stacking the metal foils on a pair of surfaces of the laminate that are opposite to each other in the stacking direction, A fourth step involves applying pressure to the laminate and the metal foil while heating them in a reduced-pressure environment, so as not to introduce air bubbles into the interface between the laminate and the metal foil, thereby integrating the laminate and the metal foil without using an adhesive. A method for manufacturing a structure, characterized by including the following:

2. The method for manufacturing the structure according to claim 1, characterized in that the pair of surfaces of the laminate are formed by molding a prepreg made by impregnating carbon fibers with resin.

3. The method for manufacturing the structure according to claim 2, characterized in that the metal foil is bonded to the resin over its entire surface on each of the pair of surfaces of the laminate.

4. The method for manufacturing the structure according to claim 1, characterized in that the laminate is a carbon fiber reinforced plastic member.

5. The method for manufacturing the structure according to any one of claims 1 to 4, characterized in that the metal foil is made of copper, aluminum, titanium, and stainless steel.

6. The method for manufacturing the structure according to any one of claims 1 to 5, characterized in that the thickness of the metal foil is on the order of microns.

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