Pellicle and method for manufacturing same

Abstract

The present invention is a pellicle having a pellicle frame, an adhesive layer on an upper end surface of the pellicle frame, and a pellicle membrane on the adhesive layer, wherein at an inner-side upper end part of the pellicle frame, the angle formed by the upper end surface and an adjacent surface on the inner side thereof is 105° or less. As a result, significant membrane wrinkling, such as that exceeding 500 μm, for example, is suppressed at the bonded portion between the adhesive layer and the pellicle membrane, and a pellicle having a favorable appearance and a method for manufacturing the same are provided.

Description

Pericle and Method for Manufacturing the Same

[0001] The present invention relates to a lithography pellicle used as dust protection for a lithography mask when manufacturing semiconductor devices such as LSIs and super LSIs, or liquid crystal display panels.

[0002] In the manufacture of semiconductors such as LSIs and super LSIs or the manufacture of liquid crystal display panels, light is irradiated onto a semiconductor wafer or a raw substrate for liquid crystal to form a pattern (Patent Document 1). If dust adheres to the exposure original plate used in this case, the dust absorbs or bends the light, resulting in problems such as the transferred pattern being deformed, the edges being rough, and the base being blackened and soiled, which impairs dimensions, quality, appearance, etc. In the present specification, the "exposure original plate" is a general term for lithography masks and reticles.

[0003] These operations are usually performed in a clean room, but it is difficult to always keep the exposure original plate clean even in this clean room. Therefore, a method of attaching a pellicle that allows light for exposure to pass well for dust protection on the surface of the exposure original plate is adopted. In this case, since the dust does not directly adhere to the surface of the exposure original plate but adheres to the pellicle film, if the focus is set on the pattern of the exposure original plate during lithography, the dust on the pellicle film becomes irrelevant to the transfer.

[0004] And the basic configuration of such a pellicle consists of a pellicle frame and a pellicle film stretched thereon. This pellicle film is made of nitrocellulose, cellulose acetate, fluorine-based polymers, etc. that transmit light (g-line, i-line, 248 nm, 193 nm, etc.) used for exposure well, and the pellicle frame is made of aluminum alloys such as A7075, A6061, A5052, etc. that have been subjected to black anodizing treatment, stainless steel, polyethylene, etc.

[0005] Furthermore, an adhesive layer made of an adhesive such as acrylic resin, epoxy resin, or fluororesin is provided on the upper part of the pellicle frame, and the pellicle film is bonded to it via this adhesive layer. In addition, an adhesive layer made of polybutene resin, polyvinyl acetate resin, acrylic resin, or silicone resin is provided on the lower part of the pellicle frame for mounting the exposure master plate, and a reticle adhesive protective liner is provided to protect the adhesive layer.

[0006] The pellicle, configured in this way, is installed to surround the pattern area formed on the surface of the exposure plate and is provided to prevent dust from adhering to the exposure plate. Therefore, this pattern area and the area outside the pellicle are isolated from each other to prevent dust from the outside of the pellicle from adhering to the pattern surface.

[0007] Japanese Patent Publication No. 2022-160364

[0008] In this case, cosmetic problems sometimes arose with the pellicle film. For example, near the inner upper end of the pellicle frame (near the boundary between the bonded and non-bonded areas of the pellicle film and the adhesive layer), the shape of the inner end of the adhesive layer may not be sharp but rounded. As a result, the pellicle film may have areas where it adheres to this rounded shape and areas where it is slightly lifted without adhering to it. Therefore, there was a drawback that irregularities or steps may occur on the surface of the pellicle film near the inner upper end of the pellicle frame, leading to cosmetic defects. In particular, the appearance is poor when large film twists exceeding 500 μm occur.

[0009] When the shape of the inner edge of the adhesive layer affects the adhesion of the pellicle film, resulting in unevenness, fine steps and irregularities appear in the pellicle film near the inner upper edge of the pellicle frame. Such a pellicle film appears distorted, and this phenomenon will henceforth be referred to as film distortion.

[0010] The present invention aims to provide a pellicle with a good appearance and a method for manufacturing the same, in which large film twists, such as those exceeding 500 μm, are suppressed at the bonding portion between the adhesive layer and the pellicle film.

[0011] To achieve the above objective, the present invention provides a pellicle having a pellicle frame, an adhesive layer on the upper end surface of the pellicle frame, and a pellicle film on the adhesive layer, characterized in that at the inner upper end of the pellicle frame, the angle between the upper end surface and the adjacent inner surface is 105° or less.

[0012] With the pellicle of the present invention, the angle between the upper surface of the inner upper end of the pellicle frame and the adjacent surface (inner upper end angle) is 105° or less. Therefore, the shape of the inner end of the adhesive layer (near the inner upper end of the pellicle frame) can be sharp rather than rounded. As a result, the pellicle film can be prevented from having an uneven adhesion state with the adhesive layer near the inner upper end of the pellicle frame, and large film twists, such as those exceeding 500 μm, are suppressed. For these reasons, the pellicle film has an excellent appearance.

[0013] In this case, the surface roughness Ra of the upper end surface can be 0.30 μm or less.

[0014] Because the surface roughness Ra of the upper end surface is 0.30 μm or less, irregularities are suppressed on the surface of the adhesive layer on the upper end surface, resulting in a highly smooth surface. Therefore, in the pellicle film, similarly, the uneven adhesion state with the adhesive layer caused by the irregularities of the adhesive layer near the inner upper end of the pellicle frame is more effectively prevented, and relatively large film twists exceeding 200 μm are suppressed. As a result, the appearance of the pellicle film is improved.

[0015] In this case, the adhesive in the adhesive layer may be made of amorphous fluororesin, the pellicle film may be made of amorphous fluororesin, and the pellicle may be for use with an ArF excimer laser.

[0016] In the case of pellicles used with ArF excimer lasers (193 nm), high light resistance is required for the pellicle film, and therefore, amorphous fluororesin is often used. Furthermore, by using amorphous fluororesin with high light resistance for the adhesive layer as well, a high-performance pellicle with even greater reliability during ArF excimer laser (193 nm) exposure is achieved. Generally, in the case of amorphous fluororesin adhesive layers, unlike liquid adhesives such as UV-curing adhesives that are bonded to the pellicle film before curing, the pellicle film is bonded by, for example, bonding it to a solid adhesive layer. In this case, the shape of the inner edge of the adhesive layer near the inner upper edge of the pellicle frame tends to be rounded rather than sharp. However, as mentioned above, the size of the inner upper edge corner of the pellicle frame is within the above range in this invention, and as a result, film twisting can be suppressed. Therefore, this invention is particularly effective for pellicles for ArF excimer lasers.

[0017] Furthermore, the angle between the upper end surface and the adjacent surface at the inner upper end can be 90° or less.

[0018] With this type of material, a superior pellicle is more reliably formed, with film twisting exceeding 500 μm being suppressed.

[0019] Furthermore, the pellicle film may be made of a polymer of butenyl vinyl ether. Also, the adhesive in the adhesive layer may be made of a polymer of allyl vinyl ether.

[0020] These materials are suitable as adhesives for the pellicle film and adhesive layer in the pellicle of the present invention.

[0021] Furthermore, the present invention provides a method for manufacturing a pellicle, comprising preparing a pellicle frame, forming an adhesive layer on the upper end surface of the prepared pellicle frame, and bonding a pellicle film onto the formed adhesive layer, characterized in that the pellicle frame is prepared such that the angle between the upper end surface and the adjacent inner surface at the inner upper end is 105° or less.

[0022] With this method of manufacturing the pellicle according to the present invention, the inner upper end angle of the prepared pellicle frame is 105° or less. Therefore, it is possible to prevent uneven adhesion between the pellicle film and the adhesive layer near the inner upper end of the pellicle frame, thereby suppressing film twisting (over 500 μm). As a result, it is possible to manufacture a pellicle with an excellent appearance.

[0023] In this case, the pellicle frame can be prepared such that the surface roughness Ra of the upper end surface is 0.30 μm or less.

[0024] Since the surface roughness Ra of the upper end surface of the pellicle frame prepared in this way is 0.30 μm or less, it is possible to more effectively prevent uneven adhesion between the pellicle film and the adhesive layer near the inner upper end of the pellicle frame and suppress film twisting (over 200 μm). As a result, it is possible to manufacture a pellicle with an even better appearance.

[0025] In this case, an amorphous fluororesin can be used as the adhesive for the adhesive layer, an amorphous fluororesin can be used as the pellicle film, and a pellicle for use with an ArF excimer laser can be manufactured.

[0026] This method suppresses film sagging and allows for the creation of a high-performance pellicle with even greater reliability during ArF excimer laser exposure.

[0027] Furthermore, as the pellicle frame, one can be prepared in which the angle between the upper end surface and the adjacent surface at the inner upper end is 90° or less.

[0028] This method allows for more reliable suppression of film twisting (over 500 μm) and the acquisition of a superior pellicle.

[0029] Furthermore, when the pellicle film is bonded to the adhesive layer, the adhesive in the adhesive layer is in a solid state, allowing the pellicle film to be bonded to it.

[0030] In particular, when bonding a pellicle film to an adhesive layer in a solid state, conventional methods tend to result in a rounded shape at the inner edge of the adhesive layer near the upper inner edge of the pellicle frame, rather than a sharp shape, which can easily lead to film twisting. However, the manufacturing method of the present invention makes it possible to sharpen the shape of the inner edge and suppress film twisting, making it particularly effective for this type of bonding.

[0031] Furthermore, the bonded parts can be heated after bonding.

[0032] This method can further increase the adhesive strength between the pellicle film and the adhesive layer.

[0033] Furthermore, a polymer of butenyl vinyl ether can be used as the pellicle film. In addition, a polymer of allyl vinyl ether can be used as the adhesive for the adhesive layer.

[0034] These materials can be suitably used as adhesives for the pellicle film and adhesive layer in the pellicle of the present invention.

[0035] The pellicle and its manufacturing method of the present invention can suppress uneven adhesion between the pellicle film and the adhesive layer near the inner upper end of the pellicle frame. Therefore, film twisting (over 500 μm) of the pellicle film can be suppressed, and damage to the appearance can be prevented.

[0036] This is an explanatory diagram showing an example of the pellicle of the present invention (90° < angle A ≤ 105°). This is an explanatory diagram showing another example of the pellicle of the present invention (angle A ≤ 90°). This is an explanatory diagram showing an example of a conventional pellicle (angle A = 135°: area without film twisting). This is an explanatory diagram showing an example of a conventional pellicle (angle A = 135°: area with film twisting). This is a plan view of a conventional pellicle film where film twisting has occurred. This is a flow chart showing an example of the process for manufacturing the pellicle of the present invention.

[0037] The present invention will be described in detail below with reference to the figures as an example of an embodiment, but the present invention is not limited to these. As mentioned above, film twisting of the pellicle film (large twists exceeding 500 μm) sometimes occurred due to defects in the adhesion state with the adhesive layer. The inventors then conducted diligent research and found that the shape of the inner upper end of the pellicle frame and the surface roughness of the upper end of the pellicle frame are important and that it is necessary to control these. Specifically, the inventors found that if a pellicle has a pellicle frame, an adhesive layer on the upper end surface of the pellicle frame, and a pellicle film on the adhesive layer, and the angle between the upper end surface and the adjacent inner surface at the inner upper end of the pellicle frame is 105° or less, then film twisting of the pellicle film (exceeding 500 μm) near the inner upper end of the pellicle frame can be suppressed, resulting in a pellicle with a good appearance, and thus completed the present invention.

[0038] Furthermore, we have discovered that if we manufacture a pellicle by preparing a pellicle frame, forming an adhesive layer on the upper end surface of the prepared pellicle frame, and bonding a pellicle film onto the formed adhesive layer, and the pellicle frame is prepared such that the angle between the upper end surface and the adjacent inner surface at the inner upper end is 105° or less, then the film twisting of the pellicle film (over 500 μm) described above can be suppressed, and a pellicle with an excellent appearance can be manufactured, thus completing the present invention.

[0039] Figure 1 shows an example of the pellicle of the present invention. Figure 2 shows an example of another embodiment of the pellicle of the present invention. The pellicle 1 of the present invention has a pellicle frame 2, an adhesive layer 3 on the upper end surface S1 of the pellicle frame 2, and a pellicle film 4 on the adhesive layer 3. Here, at the inner upper end P of the pellicle frame 2, the angle formed between the upper end surface S1 and the adjacent inner surface S2 is defined as the inner upper end angle A (hereinafter also simply referred to as angle A).

[0040] <Regarding the inner upper end corner A> In the present invention, the angle A at the inner upper end P of the pellicle frame 2 is 105° or less. Figure 1 shows an example where the angle A is greater than 90° and 105° or less. Here, the upper right corner of the pellicle frame 2 in Figure 1 is chamfered, so that the angle A is greater than 90° and 105° or less. In this case, this chamfered surface corresponds to the adjacent surface S2. The other three corners (upper left corner, lower left corner, and lower right corner of the pellicle frame 2 in Figure 1) can be chamfered, for example, to a C chamfer.

[0041] With this design, the shape of the inner end Q of the adhesive layer 3 near the inner upper end P is not so rounded but relatively sharp (compared to the outer end of the adhesive layer near the upper left corner [C chamfer: 135°] of the pellicle frame 2, it is more perpendicular to the upper end surface S1). Therefore, non-uniformity of the adhesion state between the pellicle film 4 and the adhesive layer 3 near the inner upper end P can be suppressed, and film twisting of the pellicle film 4 (large ones exceeding 500 μm) can be suppressed.

[0042] Figure 2 also shows an example where angle A is 90° or less. In this case, the upper right corner of Figure 2 is not chamfered, and the inner surface of the pellicle frame corresponds to the adjacent surface S2. When the size of angle A is 90° or less, the shape of the inner end Q of the adhesive layer 3 can be made sharper than in the case of Figure 1, and it is preferable because the effect of suppressing the non-uniformity of the adhesive state and film twisting (over 500 μm) can be obtained more reliably. The lower limit of angle A is not particularly limited as long as it is greater than 0°, but it can be, for example, about 75°.

[0043] Here, a conventional general pellicle will be described for comparison with the pellicle of the present invention. Conventionally, the pellicle frame is generally chamfered on the C surface in order to improve handling and appearance stability in the frame manufacturing process. Also in the conventional pellicle 100 shown in FIG. 3, all four corners of the pellicle frame 200 are chamfered on the C surface, and the angle A at the inner upper end portion P is 135° (that is, greater than 105°). When the angle A is greater than 105° in this way, the inner end portion Q of the adhesive layer 300 formed thereon is more likely to be rounded.

[0044] At this time, as shown in FIG. 4, in a part of the pellicle film 400, it may adhere to the rounded inner end portion Q. That is, as shown in the plan view of FIG. 5, the adhesion state varies depending on the location (generation of a non-uniform adhesion state). M1 in FIG. 5 is a location where the pellicle film 400 is not adhered to the inner end portion Q (FIG. 3), and M2 is a location where the pellicle film 400 is adhered to the inner end portion Q (FIG. 4) (generation of film deviation exceeding 500 μm). When such a large film deviation occurs, the appearance will be impaired.

[0045] On the other hand, in the pellicle 1 of the present invention where the angle A is 105° or less, since the inner end portion Q of the adhesive layer 3 is sharper than that of the conventional product, the adhesion of the pellicle film 4 to the inner end portion Q is less likely to occur, and the above-mentioned large film deviation can be extremely suppressed. Even if film deviation occurs, it can be made smaller than in the case of the conventional product.

[0046] <Regarding the surface roughness Ra of the upper end surface> In the present invention, the surface roughness Ra of the upper end surface S1 of the pellicle frame 2 on which the adhesive layer 3 is formed is not particularly limited, but it is preferably 0.30 μm or less. With such a surface roughness, irregularities are suppressed on the surface of the adhesive layer 3 on the upper end surface S1, resulting in a highly smooth surface. Therefore, near the inner upper end P of the pellicle frame 2 (especially throughout the inner circumference), the occurrence of an uneven adhesion state between the pellicle film 4 and the adhesive layer 3 caused by the above-mentioned irregularities can be further prevented, and film twisting (relatively large ones exceeding 200 μm) can be suppressed. The smaller the surface roughness Ra, the smoother the surface; for example, it is even more preferable to control it to 0.15 μm or less, which can further prevent film twisting (exceeding 200 μm). The lower limit of the surface roughness Ra can be 0 μm.

[0047] As explained above, in the pellicle 1 of the present invention, the surface roughness of corner A and upper end surface S1 is adjusted to within the above numerical range, so film twisting is extremely suppressed and the appearance is good. In conventional products, large film twists exceeding 500 μm may be observed near the inner upper end P, caused by the inner edge of the rounded adhesive layer, but as in the present invention, this can be prevented or its size suppressed by adjusting corner A. In addition, in conventional products, relatively large film twists exceeding 200 μm may be observed near the inner upper end P, caused by surface irregularities of the adhesive layer, but as in the more preferred embodiment of the present invention, this can be prevented or its size suppressed by adjusting the surface roughness Ra of the upper end surface.

[0048] <Regarding the Adhesive of the Adhesive Layer and the Material of the Pericle Film> Also, the material of each part of the pericle 1 of the present invention is not particularly limited. For example, the pericle frame 2 may be made of an aluminum alloy such as A7075, A6061, or A5052 that has been subjected to black anodizing or the like, stainless steel, polyethylene, or the like. Further, the pericle film 4 can be made of a polymer of butenyl vinyl ether. Also, the adhesive of the adhesive layer 3 can be made of a polymer of allyl vinyl ether. However, it can be appropriately determined according to the light used for exposure. As the pericle film 4, it can also be made of nitrocellulose, cellulose acetate, a fluorine-based polymer, or the like, and as the adhesive of the adhesive layer 3, it can also be made of an acrylic resin, an epoxy resin, a fluorine resin, or the like.

[0049] Here, the pericle 1 can also be for a KrF excimer laser or the like, but particularly can be for an ArF excimer laser. And in this case, as a suitable example of the material, for example, the pericle film 4 is made of an amorphous fluororesin, and the adhesive of the adhesive layer 3 is also made of an amorphous fluororesin.

[0050] In recent years, the design rule of LSI has been miniaturized to sub-quarter micron, and along with this, the short wavelength of the exposure light source has been progressing. That is, it is gradually shifting from the KrF excimer laser (248 nm), which has been the mainstream until now, to an ArF excimer laser (193 nm), immersion exposure with an ArF excimer laser (193 nm), and the like.

[0051] In the case of a pericle used with an ArF excimer laser, since high light resistance is required for the pericle film, a film made of an amorphous fluororesin as described above is preferable. For example, it can be made of a polymer of perfluorobutenyl vinyl ether. Also, regarding the adhesive of the adhesive layer, an amorphous fluororesin having high light resistance is preferable. For example, it can be made of a polymer of perfluoroallyl vinyl ether. By making such a combination, it becomes possible to obtain a high-performance pericle with even higher reliability particularly during exposure with an ArF excimer laser (193 nm).

[0052] In ArF excimer laser (193 nm) immersion lithography, the exposure light is obliquely incident on the pellicle, so to maintain light transmittance, the pellicle film thickness should be about one-third that of a typical ArF excimer laser (193 nm) pellicle film. Therefore, the pellicle film is very delicate, and conventional products tend to adhere to the inner edge of the adhesive layer, resulting in an uneven adhesion state. Accordingly, the present invention, which can solve this problem, is particularly effective for ArF excimer laser (193 nm) immersion lithography.

[0053] Next, the method for manufacturing the pellicle of the present invention will be described. As shown in Figure 6, the steps in the method of the present invention mainly consist of (step 1) preparation of the pellicle frame, (step 2) formation of the adhesive layer, and (step 3) bonding of the pellicle film. In the following description, the manufacturing of a pellicle for an ArF excimer laser will be used as an example, but the present invention is not limited to this.

[0054] (Step 1: Preparation of the pellicle frame) Prepare a pellicle frame 2 having an angle A (105° or less) as described above (more preferably having a surface roughness Ra (0.30 μm or less) on the upper end surface). By adjusting the finished shape of the pellicle frame 2 and adjusting the chamfering angle in the chamfering process, an angle A within the above numerical range can be obtained at the inner upper end P. Furthermore, more preferably, the surface roughness Ra of the upper end surface S1 can be adjusted to the above numerical range by applying a polymer coating to the surface of the pellicle frame 2. Polishing treatment can also be applied. In this way, irregularities on the upper end surface S1 and the surface of the adhesive layer 3 formed thereon can be suppressed and made smooth. In other words, fine irregularities seen in the adhesive layer near the inner upper end of the pellicle frame in conventional products can be suppressed.

[0055] (Step 2: Formation of adhesive layer) An adhesive (for example, one made of amorphous fluororesin, such as a polymer solution of perfluoroallyl vinyl ether) is applied to the upper end surface S1 of the pellicle frame 2, and then heated to remove the solvent and form a solid adhesive layer 3. At this time, by applying the adhesive solution thinly and uniformly, it is possible to more effectively sharpen the shape of the inner end Q of the adhesive layer 3.

[0056] (Step 3: Pellicle film bonding) In this step, the pellicle film 4 is first prepared. A pellicle film deposition solution (for example, one made of amorphous fluororesin, such as a polymer solution of perfluorobutenyl vinyl ether) is applied to a clean substrate with a polished surface, such as synthetic quartz, and finished to a predetermined thickness by spin coating. After spin coating, the substrate is heated on a hot plate or the like to evaporate the solvent. At this time, the residual solvent in the film on the deposition substrate after spin coating is controlled by precisely controlling the heating temperature and time. After heating, the film is peeled from the deposition substrate into a frame slightly larger than the pellicle frame to obtain the pellicle film 4.

[0057] Then, the pellicle film 4 is bonded to the pellicle frame 2 on which the adhesive layer 3 (in a solid state) has been formed. After bonding, the pellicle film 4 and the pellicle frame 2 are heated to a predetermined temperature to further increase the adhesive strength between the pellicle film 4 and the pellicle frame 2 via the adhesive layer 3. In this way, even though an amorphous fluororesin adhesive is used, film twisting exceeding 500 μm, and even film twisting exceeding 200 μm, is suppressed, and a pellicle 1 of the present invention with an excellent appearance can be manufactured.

[0058] (Example 1) The following was prepared as the pellicle frame. <Basic configuration> [Frame shape] Frame outer dimensions: 149 mm x 115 mm x 3.15 mm, Frame thickness: 2 mm, Shape of the four corners in plan view: outer R5, inner R3, Shape of the four corners in vertical cross-sectional view as shown in Figure 2: inner upper end is 90° with no chamfer, the rest are C200 chamfered, [Treatment] After black anodizing treatment, polymer electrodeposition treatment was performed.

[0059] The surface roughness of the upper end faces of the three prepared pellicle frames was measured and found to be Ra: 0.15, 0.13, and 0.12 μm. A polymer solution of perfluoroallyl vinyl ether was applied around the entire circumference of the upper end face of these pellicle frames, and the solvent was removed by heating at 100°C for 30 minutes to form an adhesive layer.

[0060] Next, a 5% concentration of perfluorobutenyl vinyl ether polymer was applied to a 6-inch (15 cm) synthetic quartz mask substrate and a uniform coating film was obtained by spin coating (800 rpm, 10 seconds). The substrate was heated at 180°C for 5 minutes to partially remove the solvent, and the film was peeled off the substrate to obtain a transparent amorphous fluoropolymer film with a thickness of 0.82 μm as a pellicle film.

[0061] The pellicle frame and pellicle film prepared above were bonded together and heated in an oven at 100°C for 10 minutes. After removing from the oven, any excess film protruding from the outside of the pellicle frame was removed to complete the pellicle.

[0062] When the three completed pellicle films and the area near the pellicle frame (near the inner upper end) were inspected using a visual inspection machine (CA-H500CX manufactured by Keyence Corporation), no film deformation exceeding 500 μm in the direction towards the frame was observed near the inner upper end, nor any film deformation exceeding 200 μm. The overall film appearance near the frame was also good.

[0063] (Example 2) Regarding the basic configuration, a pellicle frame similar to that in Example 1 was prepared, except that the inner upper end was finished at 75° without chamfering (the inner surface of the pellicle frame has an overhang shape from the upper end to the lower end, and the width of the lower end is approximately 0.83 mm). The surface roughness of the upper end surfaces of the three prepared frames was measured and found to be Ra: 0.12, 0.15, and 0.13 μm. A pellicle film was also prepared in the same manner as in Example 1. The two were bonded together and heated in an oven at 100°C for 10 minutes. After removing from the oven, the pellicle was completed in the same manner as in Example 1.

[0064] When the three completed pellicles were inspected using an appearance inspection machine in the same manner as in Example 1, no film deformation exceeding 500 μm in size toward the frame was observed near the inner upper edge, nor any film deformation exceeding 200 μm in size was observed, and the overall film appearance near the frame was good.

[0065] (Example 3) Regarding the basic configuration, the inner upper end was chamfered to an angle of 105° (angle A becomes 105°). Otherwise, a pellicle frame was prepared in the same manner as in Example 1. The surface roughness of the upper end faces of the three prepared frames was measured and found to be Ra: 0.13, 0.11, and 0.12 μm. A pellicle film was also prepared in the same manner as in Example 1. The two were bonded together and heated in an oven at 100°C for 10 minutes. After removing from the oven, the pellicle was completed in the same manner as in Example 1.

[0066] When the three completed pellicles were inspected using an appearance inspection machine in the same manner as in Example 1, no film deformation exceeding 500 μm in size toward the frame was observed near the inner upper edge, nor any film deformation exceeding 200 μm in size was observed, and the overall film appearance near the frame was good.

[0067] (Example 4) The frame shape of the basic configuration was the same as in Example 1, and a pellicle frame was prepared by polishing the upper end surface of the frame and then applying a black anodized finish. The surface roughness of the upper end surfaces of the three prepared frames was measured and found to be Ra: 0.29, 0.26, and 0.28 μm. A pellicle film was also prepared in the same manner as in Example 1. The two were bonded together and heated in an oven at 100°C for 10 minutes. After removing from the oven, the pellicle was completed in the same manner as in Example 1.

[0068] When the three completed pellicles were inspected using an appearance inspection machine in the same manner as in Example 1, no film deformation exceeding 500 μm in size in the direction toward the frame was observed near the inner upper edge. Although very fine irregularities were observed near the inner upper edge, most were small, about 100 μm in size, and there was no film deformation exceeding 200 μm, and the overall film appearance near the frame was good.

[0069] (Example 5) Regarding the basic configuration, the inner upper end was chamfered to an angle of 105° (angle A becomes 105°). In addition, a pellicle frame was prepared by polishing the upper end surface of the frame and then applying black anodizing treatment. All other than that, the pellicle frame was prepared in the same manner as in Example 1. The surface roughness of the upper end surfaces of the three prepared frames was measured and found to be Ra: 0.30, 0.27, and 0.26 μm. A pellicle film was also prepared in the same manner as in Example 1. The two were bonded together and heated in an oven at 100°C for 10 minutes. After removing from the oven, the pellicle was completed in the same manner as in Example 1.

[0070] When the three completed pellicles were inspected using an appearance inspection machine in the same manner as in Example 1, no film deformation exceeding 500 μm in size in the direction toward the frame was observed near the inner upper edge. Although very fine irregularities were observed near the inner upper edge, most were small, about 100 μm in size, and there was no film deformation exceeding 200 μm, and the overall film appearance near the frame was good.

[0071] (Comparative Example 1) Regarding the basic configuration, the inner upper end was chamfered to C200 so that it was at an angle of 135° (angle A became 135°). Otherwise, the pellicle frame was prepared in the same manner as in Example 1. The surface roughness of the upper end faces of the three prepared frames was measured and found to be Ra: 0.13, 0.11, and 0.13 μm. A pellicle film was also prepared in the same manner as in Example 1. The two were bonded together and heated in an oven at 100°C for 10 minutes. After removing from the oven, the pellicle was completed in the same manner as in Example 1.

[0072] When the three completed pellicles were inspected using an appearance inspection machine in the same manner as in Example 1, it was found that the film had been deformed in the direction toward the frame by more than 500 μm near the inner upper edge in the first pellicle at four locations on the long side and two locations on the short side, in the second pellicle at three locations on the long side and two locations on the short side, and in the third pellicle at four locations on the long side and four locations on the short side. As a result, there were significant defects in the appearance of the film near the frame.

[0073] (Comparative Example 2) Regarding the basic configuration, the inner upper end was chamfered so that it was at an angle of 120° (angle A became 120°). Otherwise, the pellicle frame was prepared in the same manner as in Example 1. The surface roughness of the upper end faces of the three prepared frames was measured and found to be Ra: 0.14, 0.11, and 0.12 μm. A pellicle film was also prepared in the same manner as in Example 1. The two were bonded together and heated in an oven at 100°C for 10 minutes. After removing from the oven, the pellicle was completed in the same manner as in Example 1.

[0074] When the three completed pellicles were inspected using a visual inspection machine in the same manner as in Example 1, several film deformations exceeding 500 μm in size were observed near the inner upper edge. One deformation was found on the long side of the first pellicle, two on the long side of the second pellicle, and one on the long side and one on the short side of the third pellicle. As a result, there were significant defects in the film appearance near the frame.

[0075] (Example 6) The frame shape of the basic configuration was the same as in Example 1, but a frame was prepared that had been treated with black anodizing and then polymer electrodeposition. The surface roughness of the upper end faces of the three prepared frames was measured and found to be Ra: 0.49, 0.57, and 0.43 μm. A pellicle film was also prepared in the same manner as in Example 1. The two were bonded together and heated in an oven at 100°C for 10 minutes. After removing from the oven, the pellicle was completed in the same manner as in Example 1.

[0076] When the three completed pellicles were inspected using an appearance inspection machine in the same manner as in Example 1, no film twists exceeding 500 μm in size in the direction inward of the frame were observed near the inner upper end of any of the three pellicles. However, numerous fine film twists exceeding 200 μm were observed around the entire inner circumference of the pellicle frame (the entire area near the inner upper end). These fine film twists were not observed in Examples 1-3, 5, and Comparative Examples 1 and 2, and were larger than the fine irregularities observed in Example 4. Nevertheless, the film appearance near the frame was considerably better than that of Comparative Examples 1 and 2.

[0077] Table 1 summarizes the results described above.

[0078] From the above results, it was found that by making the angle A at the inner upper end of the pellicle frame 105° or less, the shape of the inner end of the adhesive layer such as amorphous fluororesin could be made sharper, and the occurrence of film twists exceeding 500 μm in the direction inward of the frame, which are seen at the bonded / unbonded boundary of the pellicle film (near the inner upper end of the pellicle frame), could be suppressed. Furthermore, it was confirmed that by making the surface roughness Ra of the upper end surface of the pellicle frame 0.30 μm or less, fine film twists of about 200 μm could also be suppressed. Only Examples 1-5 were able to achieve suppression of both types of film twists. In addition, although Example 6 was able to suppress film twists exceeding 500 μm, Comparative Examples 1-2 produced noticeable film twists exceeding 500 μm.

[0079] The findings obtained in this invention indicate that by modifying the shape of the inner upper end of the pellicle frame (i.e., by setting the angle A ≤ 105°) (and further controlling the surface roughness Ra of the upper end surface to 0.30 μm or less), it becomes easier to manufacture a superior pellicle that does not have undesirable film twists exceeding 500 μm (and even suppresses film twists exceeding 200 μm).

[0080] This specification includes the following embodiments: [1]: A pellicle having a pellicle frame, an adhesive layer on the upper end surface of the pellicle frame, and a pellicle film on the adhesive layer, wherein the angle between the upper end surface and an adjacent inner surface at the inner upper end of the pellicle frame is 105° or less. [2]: The pellicle according to [1], wherein the surface roughness Ra of the upper end surface is 0.30 μm or less. [3]: The pellicle according to [1] or [2], wherein the adhesive of the adhesive layer is made of amorphous fluororesin, the pellicle film is made of amorphous fluororesin, and the pellicle is for use with an ArF excimer laser. [4]: ​​Any of the pellicles according to [1] to [3], wherein the angle between the upper end surface and the adjacent surface at the inner upper end is 90° or less. [5]: Any of the pellicles according to [1] to [4], wherein the pellicle film is made of a polymer of butenyl vinyl ether. [6]: Any of the pellicles from [1] to [5] above, wherein the adhesive in the adhesive layer is made of a polymer of allyl vinyl ether. [7]: A method for manufacturing a pellicle, comprising preparing a pellicle frame, forming an adhesive layer on the upper end surface of the prepared pellicle frame, and bonding a pellicle film onto the formed adhesive layer, wherein the pellicle frame is prepared such that the angle between the upper end surface and the adjacent inner surface at the inner upper end is 105° or less. [8]: The method for manufacturing a pellicle according to [7] above, wherein the pellicle frame is prepared such that the surface roughness Ra of the upper end surface is 0.30 μm or less. [9]: The method for manufacturing a pellicle according to [7] or [8] above, wherein the adhesive in the adhesive layer is made of amorphous fluororesin, the pellicle film is made of amorphous fluororesin, and the pellicle is manufactured for use with an ArF excimer laser.

[10] : A method for manufacturing a pellicle according to any one of [7] to [9] above, wherein the pellicle frame is prepared such that the angle between the upper end surface and the adjacent surface at the inner upper end is 90° or less.

[11] : A method for manufacturing a pellicle according to any of [7] to

[10] above, wherein when the pellicle film is bonded to the adhesive layer, the adhesive in the adhesive layer is solid when the pellicle film is bonded.

[12] : A method for manufacturing a pellicle according to

[11] above, wherein the bonding is heated after bonding.

[13] : A method for manufacturing a pellicle according to any of [7] to

[12] above, wherein the pellicle film is made of a polymer of butenyl vinyl ether.

[14] : A method for manufacturing a pellicle according to any of [7] to

[13] above, wherein the adhesive in the adhesive layer is made of a polymer of allyl vinyl ether. Label for use.

[0081] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that has substantially the same technical idea as described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. A pellicle having a pellicle frame, an adhesive layer on the upper end surface of the pellicle frame, and a pellicle film on the adhesive layer, characterized in that at the inner upper end of the pellicle frame, the angle between the upper end surface and the adjacent inner surface is 105° or less.

2. The pellicle according to claim 1, characterized in that the surface roughness Ra of the upper end surface is 0.30 μm or less.

3. The pellicle according to claim 1, characterized in that the adhesive of the adhesive layer is made of amorphous fluororesin, the pellicle film is made of amorphous fluororesin, and the pellicle is for use with an ArF excimer laser.

4. The pellicle according to claim 1, characterized in that the angle between the upper end surface and the adjacent surface at the inner upper end is 90° or less.

5. The pellicle according to claim 1, characterized in that the pellicle film is made of a polymer of butenyl vinyl ether.

6. The pellicle according to claim 1, characterized in that the adhesive of the adhesive layer is made of a polymer of allyl vinyl ether.

7. A method for manufacturing a pellicle, comprising preparing a pellicle frame, forming an adhesive layer on the upper end surface of the prepared pellicle frame, and bonding a pellicle film onto the formed adhesive layer, characterized in that the pellicle frame is prepared such that the angle between the upper end surface and the adjacent inner surface at the inner upper end is 105° or less.

8. The method for manufacturing a pellicle according to claim 7, characterized in that the pellicle frame is prepared such that the surface roughness Ra of the upper end surface is 0.30 μm or less.

9. The method for manufacturing a pellicle according to claim 7, characterized in that an amorphous fluororesin is used as the adhesive for the adhesive layer, an amorphous fluororesin is used as the pellicle film, and the pellicle is manufactured for use with an ArF excimer laser.

10. The method for manufacturing a pellicle according to claim 7, characterized in that the pellicle frame is prepared such that the angle between the upper end surface and the adjacent surface at the inner upper end is 90° or less.

11. The method for manufacturing a pellicle according to claim 7, characterized in that when the pellicle film is bonded to the adhesive layer, the adhesive in the adhesive layer is in a solid state when the pellicle film is bonded.

12. The method for manufacturing a pellicle according to claim 11, characterized in that the pellicle is heated after bonding.

13. The method for producing a pellicle according to claim 7, characterized in that the pellicle membrane is made of a polymer of butenyl vinyl ether.

14. The method for producing a pellicle according to claim 7, characterized in that an adhesive made of a polymer of allyl vinyl ether is used as the adhesive for the adhesive layer.

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