Pellicle Frame and Pellicle Assembly with the same

Abstract

The pellicle frame comprises a pair of frame members. The frame members are each formed in a shape corresponding to the support portion of the pellicle and are joined together so that their plate surfaces overlap to form a two-layer structure. Recesses are formed in mutually corresponding portions of the inner surfaces of the pellicle members facing each other. The recesses form ventilation holes that are opened from the side of the plate surfaces when the pellicle members are joined together. A filter is interposed within the ventilation holes. Cleaning and inspection of the pellicle frame are easy, and the generation of particles caused during the processing of filter manufacturing materials is minimized. In addition, a sufficient cushioning effect can be obtained to prevent membrane damage due to pressure changes within the internal space of the pellicle frame.

Description

Technology Field

[0001] The present invention relates to a pellicle frame, and more specifically, to a pellicle frame used to mount a pellicle on the upper part of a photomask and a pellicle assembly equipped with such a pellicle frame. Background Technology

[0003] EUV lithography technology using 13.5 nm wavelength Extreme Ultra-Violet (EUV) exposure light is being developed to realize fine patterns. In the lithography process, a photomask is used as a substrate for patterning; however, if impurities such as particles or foreign substances are attached to the photomask, the exposure light may be absorbed or reflected due to these impurities, potentially damaging the transferred pattern. Accordingly, a method of mounting a pellicle on the surface of the photomask is being used to prevent impurities from adhering to the surface. Recently, as circuit line widths have become finer, the size of impurities that can affect pattern damage has also decreased, making the role of the pellicle for photomask protection even more critical.

[0004] FIG. 1 is a drawing illustrating a pellicle assembly with a pellicle attached to a frame.

[0005] The pellicle assembly (80) is composed of a pellicle (30) and a pellicle frame (50).

[0006] The pellicle (30) comprises a rectangular membrane (20) that transmits exposure light and a support portion (10) for supporting the membrane (20). Generally, a pellicle (30) with a structure as shown in FIG. 1 is produced by forming a membrane (20) on a silicon substrate and then etching the lower surface of the substrate to form a support portion (10).

[0007] When the fabrication of the pellicle (30) having a membrane (20) and a support member (10) is completed, a pellicle frame (50) is attached to the lower surface of the support member (10). In order for the pellicle (30) to be used in the exposure process, the pellicle (30) must be mounted on a photomask (P), and as a preliminary process for this, a pellicle frame (50) is attached to the lower surface of the support member (10). An adhesive is applied to the upper surface of the pellicle frame (50) to bond the support member (10) and the pellicle frame (50). The fabrication of the pellicle assembly (80) is completed by attaching the support member (10) of the pellicle (30) to the upper surface of the pellicle frame (50).

[0008] The pellicle (30) is mounted on the photomask by attaching the pellicle assembly (80) to the photomask (P). An adhesive is applied to the lower surface of the pellicle frame (50) to bond the pellicle assembly (80) and the photomask (P).

[0009] The pellicle assembly (80) is introduced into the exposure device and used while mounted on the photomask (P). During the exposure process, the inside of the exposure device is maintained in a vacuum state, and to this end, the air inside the exposure device is exhausted to the outside before the exposure process is performed. At this time, due to the pressure of exhaust, the pellicle (30) is subjected to pressure due to the exhaust of air within the internal space (S) of the pellicle assembly (80), more precisely, the internal space (S) formed by the pellicle (30), the pellicle frame (50), and the photomask (P). During this process, the membrane (20), which is a very thin film, may be damaged. To prevent this, a ventilation hole is formed in the pellicle frame (50).

[0010] FIG. 2 is a partial enlarged cross-sectional view of FIG. 1, showing the detailed structure of the pellicle frame (50) in particular. The pellicle frame (50) has a column-shaped cross-section and, in a planar view, has a rectangular frame shape that is open in the vertical direction.

[0011] The pellicle frame (50) has a ventilation hole (52) formed to penetrate its side wall. A number of ventilation holes (52) are formed along the side wall of the pellicle frame (50) at predetermined intervals in a horizontal direction. The ventilation holes (52) function to connect the internal space (S) formed between the pellicle assembly (80) and the photomask (P) with the external space as the pellicle assembly (80) is mounted on the photomask (P). During the process of vacuuming the inside of the device, the air in the internal space (S) is discharged to the outside through the ventilation hole (52), and thereby, no pressure difference occurs between the internal space (S) and the outside of the pellicle assembly (80), preventing damage to the membrane (20).

[0012] Thus, the ventilation hole (52) functions to prevent damage to the membrane (20), but on the other hand, the ventilation hole (52) may provide a passage for particles to enter the internal space (S) from the outside. Therefore, to prevent the entry of external particles, a filter (56) is installed in the ventilation hole (52). The filter (56) is installed in the form of a filtering membrane positioned in an upright direction to block the ventilation hole (52). To install the filter (56), a filter receiving hole (52a) is formed in the central part of the ventilation hole (52) to penetrate the plate surface of the pellicle frame (50) in an up-and-down direction, thereby accommodating the upper and lower regions of the filter (56). The filter (56) is installed in the frame (50) by being inserted through this receiving hole (52a).

[0013] Air passing through the ventilation hole (52) passes through the filter (56). Therefore, air flowing into the internal space (S) through the ventilation hole (52) is filtered by the filter (56), thereby preventing external foreign substances or particles from entering the internal space (S).

[0014] In this conventional structure, a processing process must be performed to form a ventilation hole (52) on the side of the pellicle frame (50) for the installation of the filter (56). For example, a process of forming the ventilation hole (52) by drilling it with a precision drill is required. Since this process generates particles, a precise cleaning process must be performed to remove particles from the ventilation hole (52) after the ventilation hole (52) is formed. However, since the diameter of the ventilation hole (52) is very small, cleaning and inspection of particles remaining inside the ventilation hole (52) is very difficult.

[0015] In addition, in this conventional structure, since the filter (56) is installed by penetrating the receiving hole (52a) and must be shielded across the ventilation hole (52) after installation, the filter (56) must be processed into a shape such as a wide rectangular membrane with a certain thickness. Accordingly, to manufacture the filter (56), a material for manufacturing the filter, for example, in the shape of a rectangular column, must be prepared and then thinly sliced. This means that the entire outer surface of the filter (56) (the left and right surfaces of the filter (56) in FIG. 2) consists of a surface formed by cutting with a cutting tool. Consequently, the outer surface of the filter (56) becomes covered with particles generated during cutting, and the filter (56), which is installed to prevent particles, actually becomes a factor that causes particles.

[0016] In addition, there is a disadvantage in that as the function of the filter (56) is enhanced, the protection of the membrane (20) against pressure changes in the internal space (S) may be insufficient. For example, in order to increase the filtering performance of the filter (56), the filter (56) must have a high density, so the strength of hermetically closing the ventilation holes (52) increases. Therefore, if the pressure change in the internal space (S) is large, the ventilation holes (52) cannot buffer the pressure change due to the strong shielding power of the filter (56), and this causes damage to the membrane (20). Conversely, if the density of the filter (56) is lowered to increase the pressure buffering effect through the ventilation holes (52) during high pressure changes, the filtering performance of the filter (56) is weakened. The problem to be solved

[0018] The present invention has been devised to solve the aforementioned problems, and the objective of the present invention is to provide a method for facilitating the cleaning and inspection of a pellicle frame.

[0019] Another objective of the present invention is to provide a method for minimizing the generation of particles caused during the processing of filter manufacturing materials for filter production.

[0020] Another objective of the present invention is to provide a method that can obtain a sufficient buffering effect to prevent membrane damage due to pressure changes in the internal space of the pellicle frame, while simultaneously enhancing the filtering effect. means of solving the problem

[0022] To achieve the above objective, the present invention provides a pellicle frame used to mount a pellicle on a photomask by attaching a pellicle having a membrane for transmitting exposure light and a support portion supporting an outer edge region of the membrane, wherein the pellicle is formed in a shape corresponding to the support portion and is coupled to each other so that its plate surfaces overlap to form a two-layer structure, and each has a recess formed in mutually corresponding portion regions of each inner surface facing each other to form a ventilation hole that is opened from the side of the plate surface in a coupled state; and a filter interposed within the ventilation hole between the pair of frame members to block the ventilation hole.

[0023] In the pellicle frame, a plurality of the above-mentioned depressions are formed in each of the above-mentioned frame members to form a plurality of the above-mentioned ventilation holes.

[0024] It is preferable that the height of the cross-section of the filter is higher than the height of the ventilation hole.

[0025] A receiving groove is formed on the bottom surface of each of the above-mentioned recesses to accommodate the portion of the filter that contacts the bottom surface.

[0026] The above receiving groove is formed along the length direction of the bottom surface.

[0027] The above-mentioned receiving groove has a cross-section in the shape of a partial arc, and the above-mentioned filter is formed so that the outer shape of its cross-section is circular.

[0028] Alternatively, the receiving groove may have a cross-section that is partially polygonal in shape, and the filter may be formed such that the outer shape of its cross-section is polygonal.

[0029] It is preferable that the above filter has a tubular shape.

[0030] The above receiving groove is formed such that its length along the length direction is longer than the length of the above recess.

[0031] It is preferable that the sections at both ends of the receiving groove that exceed the formation section of the above-mentioned depression be formed so that their cross-sections have a semicircular or polygonal shape.

[0032] An adhesive that provides adhesion to the filter may be applied to at least a portion of the above-mentioned receiving groove.

[0033] On the side of at least one of the above pair of frame members, a pin groove is formed to provide a portion for gripping the pellicle frame by inserting a pin from the outside.

[0034] Each of the above-mentioned frame members has a joint formed therein that is joined by mutual fitting.

[0035] The above-mentioned joint is formed between a plurality of the above-mentioned ventilation holes.

[0036] Meanwhile, according to another embodiment of the present invention, the filter is fixed to a filter fixing member and disposed within the ventilation hole by installing the filter fixing member between the pair of frame members. The filter fixing member has a ventilation portion that partially exposes the filter so that the ventilation hole is blocked by the filter.

[0037] Preferably, in this case, the filter has the shape of a sheet that extends in a horizontal direction and is positioned with its plate surface upright, and the filter fixing member includes a pair of fixing members each coupled to the filter on both sides of the filter, and the ventilation portion is formed in the inner region of the edge area of ​​each of the fixing members.

[0038] In one variation, at least one of the fixing members has a recessed portion formed in the edge region of the surface in contact with the filter so as to accommodate the filter.

[0039] As another variation, a recess is formed in one of the fixed members and a protrusion is formed in the other of the fixed members, so that a pair of the fixed members are joined together by mutual fitting of the recess and the protrusion.

[0040] The above-mentioned lumbar portion and the above-mentioned protrusion are configured to be mutually coupled in such a state where a part of the filter is inserted into the above-mentioned lumbar portion.

[0041] According to another aspect of the present invention, a pellicle assembly is provided, characterized by comprising: a pellicle frame having a structure as described above; and a pellicle attached to the pellicle frame. Effects of the invention

[0043] According to the present invention, a pellicle frame is formed by the combination of two frame members arranged vertically, and as a ventilation hole is formed by the combination of the two frame members, cleaning and inspection of particles are easily performed.

[0044] Furthermore, since the filter is manufactured by cutting a tubular material to a specific length along its length, the size of the cut surface in a single filter is minimized. Consequently, the generation of particles caused by the cutting process is minimized. Moreover, in this invention, since the cut surface is not placed within the ventilation holes, the phenomenon of particles generated from the cut surface entering the internal space of the pellicle through the ventilation holes does not occur.

[0045] In addition, in the present invention, the filter is manufactured to have a tube shape and is arranged along the longitudinal direction of the plate surface of the pellicle frame, so that the ventilation holes are double-shielded by a single filter. Therefore, even if the density of the filter is low, a sufficient filtering effect can be obtained through double filtering, and even if a sudden pressure change occurs between the inside and outside of the pellicle frame, the pressure change is buffered by the space between the double filters, thereby preventing damage to the membrane.

[0046] Furthermore, if a method is adopted in which the filter is fixed within the filter fixture and the filter fixture is installed within the ventilation hole, the assembly process of the filter can be easily performed. Brief explanation of the drawing

[0048] FIG. 1 is a drawing illustrating a pellicle assembly with a pellicle attached to a frame. FIG. 2 is a partially enlarged cross-sectional view of FIG. 1. FIG. 3 is an exploded perspective view of a pellicle frame according to a first embodiment of the present invention. FIG. 4 is a side view of the combined state of FIG. 3. FIG. 5 is a top view of the first frame member of FIG. 3. Fig. 6 is a partial perspective view of Fig. 5. FIG. 7 is a lower view of the second frame member of FIG. 3. Fig. 8 is a partial perspective view of Fig. 7. Fig. 9 is a partial enlarged view of Fig. 6. FIG. 10 is a drawing showing the state in which the filter is installed in FIG. 9. FIG. 11 is an enlarged perspective view of the filter of FIG. 10. FIG. 12 is a drawing illustrating a filter material for manufacturing the filter of FIG. 10. FIG. 13 is a cross-sectional view of the ventilation hole portion of FIG. 4. FIG. 14 is an exploded perspective view of a filter assembly used in a pellicle frame according to a second embodiment of the present invention. FIG. 15 is a perspective view of the combined state of FIG. 14. FIG. 16 is a drawing similar to FIG. 10, showing the filter assembly of FIG. 15 mounted. FIG. 17 is a drawing similar to FIG. 13, showing a cross-section of the filter assembly of FIG. 15 mounted. FIG. 18 is an exploded perspective view of a filter assembly according to a first variation of a second embodiment of the present invention. FIGS. 19 and FIGS. 20 are enlarged views of parts A and B of FIG. 18, respectively. FIG. 21 is a drawing similar to FIG. 17, showing a cross-section of the filter assembly of FIG. 18 mounted thereon. FIG. 22 is an exploded perspective view of a filter assembly according to a second variation of a second embodiment of the present invention. FIGS. 23 and FIGS. 24 are enlarged views of parts C and D of FIG. 22, respectively. FIG. 25 is a side view illustrating the state in which a filter is attached to the first fixed member in FIG. 22. FIG. 26 is a partially enlarged cross-sectional view of the first fixing member and the second fixing member in FIG. 22 in a mutually coupled state. FIGS. 27 to 30 are drawings illustrating a filter assembly according to a third variation of a second embodiment of the present invention in a manner similar to FIGS. 22 to 25, respectively. Specific details for implementing the invention

[0049] The present invention will be described in detail below with reference to the attached drawings. In the description of the present invention, a detailed description of the general structure of the pellicle assembly is omitted, and the content described with reference to FIGS. 1 and FIGS. 2 in the description of the prior art is adopted as the description of the present invention. In the description of the present invention, components shown in FIGS. 1 and FIGS. 2 with respect to the pellicle (30) are cited using the same reference numerals.

[0050] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 3 to 13.

[0051] FIG. 3 is an exploded perspective view of a pellicle frame according to a first embodiment of the present invention, and FIG. 4 is a side view of the combined state of FIG. 3. As described above in the description of the prior art, the pellicle (30) comprises a rectangular membrane (20) for transmitting exposure light and a support member (10) that supports the outer edge region of the membrane (20), and the pellicle frame (300) is mounted on the upper part of a photomask (P) with the pellicle (30) attached thereto.

[0052] The pellicle frame (300) of the present invention comprises a pair of frame members (100, 200), namely a first frame member (100) and a second frame member (200), and is also configured to include a filter (400).

[0053] The first frame member (100) and the second frame member (200) are each formed in a rectangular frame shape corresponding to the support portion (10) of the pellicle (30). Here, the rectangular frame shape refers to a shape that has an overall rectangular plate shape, but with only the edge area remaining and the rest removed. At this time, the shape of the removed portion corresponds to the remaining area of ​​the membrane (20) excluding the area where the support portion (10) is formed, that is, the window area through which EUV exposure light is transmitted. Accordingly, each frame member (100, 200) has a shape in which four thin, long bar-shaped plates are connected to form a rectangular frame. Each frame member (100, 200) is formed as a single member and manufactured by a single molding process.

[0054] The first frame member (100) and the second frame member (200) are joined together so that their plate surfaces overlap to form a two-layer structure. Specifically, the first frame member (100) is located at the bottom and the second frame member (200) is located at the top, so that they are joined together in the vertical direction. A filter (400) is interposed between the two frame members (100, 200).

[0055] FIGS. 5 and 6 are drawings illustrating the first frame member (100) of FIG. 3, and FIGS. 7 and 8 are drawings illustrating the second frame member (200) of FIG. 3. In FIGS. 7 and 8, the state of the second frame member (200) is shown in an inverted state from FIG. 3 in order to clearly illustrate the structure of the second frame member (200).

[0056] Each frame member (100, 200) has a recess (110) formed on each inner surface facing each other, that is, on the upper surface of the first frame member (100) and the lower surface of the second frame member (200). Each recess (110) is formed in mutually corresponding areas of each frame member (100, 200). Accordingly, when the two frame members (100, 200) are joined together, the two recesses (110) facing each other form a shape in which a ventilation hole (330) is opened on the side of the plate surface of the pellicle frame (300). A filter (400) is interposed within this ventilation hole (330) and arranged to block the ventilation hole (330). A plurality of recesses (110) are formed in each frame member (100, 200), and accordingly, the pellicle frame (300) has a plurality of ventilation holes (330).

[0057] The recessed portion (110) is formed in a shape that is recessed to a uniform depth from the plate surface of the frame member (100, 200) over a certain section along the length direction of each frame member (100, 200). Additionally, the recessed portion (110) is configured to be recessed over the entire section in the width direction of the plate surface of the frame member (100, 200).

[0058] A receiving groove (120) is formed on the bottom surface of the recess (110) so as to be additionally recessed from the recess (110). The receiving groove (120) is formed along the length direction of the bottom surface of the recess (110), and is formed so as to be recessed such that both ends (122) extend outward beyond the formed section of the recess (110).

[0059] The receiving groove (120) is formed to partially receive the filter (400) in a shape corresponding to the outer shape of the filter (400), specifically such that its cross-section has the shape of a partial arc. However, the outer shape is not limited to the shape of an arc and is determined to correspond to the shape of the filter (400). The filter (400) may have a cross-section that is polygonal, such as a square.

[0060] The filter (400) is positioned along the longitudinal direction within the recess (110), and in an embodiment of the present invention, as described below, the cross-sectional shape is formed to be circular, more specifically, the cross-sectional shape to be tubular. Accordingly, a portion of the filter (400) in contact with the bottom surface of the recess (110) is received within the receiving groove (120). Through this receiving groove (120), the position of the filter (400) within the ventilation hole (330) is stably maintained. Meanwhile, to further strengthen the fixing force of the filter (400), an adhesive that provides adhesion to the filter (400) may be applied within the receiving groove (120). The portion where the adhesive is applied may be the entire section within the receiving groove (120) or a partial section. For example, the adhesive may be applied only to the two end sections (122) of the entire section of the receiving groove (120) that are not located within the recess (110).

[0061] FIG. 9 is a partial enlarged view of FIG. 6, and FIG. 10 is a drawing showing the state in FIG. 9 with the filter (400) installed.

[0062] As described above, the receiving groove (120) is formed such that its length along its longitudinal direction is longer than the length of the recess (110) itself. That is, the receiving groove (120) has a shape that is recessed into the bottom surface of the recess (110), and both ends (122) of the receiving groove (120) extend beyond the section of the recess (110), and these extended ends (122) are formed by a portion that is directly recessed from the plate surface of each frame member (100, 200). The sections of both ends (122) of the receiving groove (120) that extend beyond the formed section of the recess (110) are formed to have a semicircular shape so that their cross-section conforms to the tube-shaped filter (400).

[0063] With this structure, as illustrated in FIG. 10, most of the filter (400) is positioned within the recess (110), and some of the ends of the filter (400) are placed within the semicircular ends (122) of the receiving groove (120). That is, the filter (400) is configured such that the height of its cross-section is higher than the height of the ventilation hole (330), and accordingly, the upper part and the lower part of the cross-section of the filter (400) are respectively received within the upper receiving groove (120) and the lower receiving groove (120), thereby fixing the position of the filter (400) within the recess (110). When the two frame members (100, 200) are combined, the ventilation hole (330) formed by the recess (110) is blocked by the filter (400), and both ends of the filter (400) are fixed by being pressed by the interlocking of the semicircular ends (122) of the two receiving grooves (120).

[0064] Meanwhile, if the filter (400) is formed to have a polygonal cross-section, the two ends (122) of the receiving groove (120) are configured to have a polygonal shape that accommodates half of the cross-section of the filter (400) in correspondence with the shape of the filter (400).

[0065] Each frame member (100, 200) has a connecting portion (150, 250) formed therein that is joined by mutual fitting. Specifically, as shown in FIGS. 7 and 8, a protrusion (250) protruding from the inner surface of the second frame member (200) is formed therein, and as shown in FIGS. 5 and 6, a recessed portion (150) formed on the inner surface of the first frame member (100) in a shape corresponding to this protrusion (250) is formed therein, so that the connecting portion (150, 250) is formed by a pair of the protrusion (250) and the recessed portion (150). The first frame member (100) and the second frame member (200) are joined together by mutual fitting of these connecting portions (150, 250).

[0066] In an embodiment of the present invention, a total of eight connecting parts (150, 250) are formed at each of the four corners and four sides of the pellicle frame (300). The number of connecting parts (150, 250) can be determined as needed. In the case of the connecting parts (150, 250) formed at the corners, they are formed to form an overall "L" shape according to the shape of the bent plate surface of the corners. The shape of the connecting parts (150, 250) can be configured in various ways as long as they are detachably connected by mutual fitting of the protrusions and the recesses. The connecting parts (150, 250) are formed in the area between the ventilation holes (330). Accordingly, the connecting parts (150, 250) and the ventilation holes (330) are alternately arranged along the plate surface of the pellicle frame (300).

[0067] Meanwhile, a pin groove (180) is formed on the outer surface of the frame member (100, 200). Each pin groove (108) is formed at a mutually corresponding position between the first frame member (100) and the second frame member (200), and when the two frame members (100, 200) are combined, the two pin grooves (180) form a single hanging groove. The pin groove (180) provides a portion of the pellicle frame (300) into which external equipment can insert a pin to grip it. This external equipment refers to equipment that grips the pellicle frame (300), for example, to move the manufactured pellicle frame (300) to a storage location or to mount the pellicle frame (300) onto a photomask (P). Pin grooves (180) are formed at least two locations on the pellicle frame (300), particularly at two locations on mutually opposite sides, so that external equipment can hook the pellicle frame (300) by inserting pins into two or more pin grooves (180). The number and location of the pin grooves (180) can be varied as needed.

[0068] FIG. 11 is an enlarged perspective view of the filter (400) of FIG. 10. The filter (400) of the present invention has an overall tubular shape. The material of the filter (400) can be appropriately selected as needed, and it is preferable that the material be one having a plurality of pores.

[0069] FIG. 12 is a drawing illustrating a filter material for manufacturing the filter of FIG. 10. After preparing a very long tube-shaped filter material (400a), the filter material (400a) can be cut in the direction of the arrow to a predetermined length to form the shape of the filter (400) of FIG. 11, thereby obtaining each filter (400). Since the filter (400) is manufactured by cutting the tube-shaped filter material (400a) in this way, the cut surface of the filter (400) becomes the surface of both ends of the filter (400). As shown in FIG. 10, when the filter (400) is installed, the cut surface is placed within both ends (122) of the receiving groove (120). Accordingly, when the first frame member (100) and the second frame member (200) are combined as in FIG. 4, the cut surface is not placed within the ventilation hole (330) and is not exposed to the outside. Therefore, the phenomenon in which foreign substances generated on the cutting surface during the manufacturing process of the filter (400) act as particles is prevented.

[0070] Fig. 13 is a cross-sectional view of the ventilation hole portion of Fig. 4.

[0071] With the filter (400) placed between the two frame members (100, 200), the film of the filter (400) is arranged in a double layer in the direction in which air flows in / out through the ventilation hole (330) due to the cross-sectional structure of the tube-shaped filter (400). Therefore, due to the double filtering effect, even if the density of the filter (400), that is, the degree of airtight closure of the ventilation hole (300), is lowered, a sufficient filtering effect can be obtained. In addition, even if a sudden pressure change occurs between the inside and outside of the pellicle frame (300), the pressure change is buffered by the inside of the tube, that is, the space between the double filters, so that damage to the membrane (20) is effectively prevented.

[0072] Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 14 to 30. In the description of the second embodiment below, detailed descriptions of configurations that are substantially identical to those described in the first embodiment above will be omitted, and such configurations will be adopted as configurations of the second embodiment. For convenience of illustration and description, such substantially identical configurations will be cited using the same reference numerals.

[0073] FIGS. 14 to 17 are drawings illustrating the basic configuration of a second embodiment of the present invention.

[0074] The second embodiment differs from the first embodiment described above in that a filter assembly comprising a filter (420) and a filter fixing member (500) is employed instead of a filter (400). That is, the filter (420) is not installed alone within the ventilation hole (330), but is installed within the ventilation hole (330) after being prepared as a filter assembly fixed within the filter fixing member (500). The configuration of the filter assembly is described below.

[0075] FIG. 14 is an exploded perspective view of a filter assembly used in a pellicle frame, and FIG. 15 is a perspective view of FIG. 14 in an assembled state.

[0076] In this embodiment, the filter (420) has an overall rectangular sheet shape, and the sheet is extended horizontally and positioned with its surface standing upright. The filter fixing member (500) functions to fix the filter (420). That is, the filter (420) is fixed to the filter fixing member (500), and in this state, the filter fixing member (500) is installed between a pair of frame members (100, 200) so as to be placed within the ventilation hole (330).

[0077] The filter fixing device (500) includes a pair of fixing members (510, 520) that are respectively connected to the filter (420) on both sides of the filter (420). Each fixing member (510, 520) has an overall rectangular frame shape. Specifically, the first fixing member (510) has a shape in which the inner region is removed while leaving only the edge region of a horizontally elongated rectangular plate, thereby forming a ventilation portion (512). The second fixing member (520) likewise has a shape in which the inner region is formed while leaving only the edge region of an elongated rectangular plate. The first fixing member (510) and the second fixing member (520) have substantially the same shape. As the first fixing member (510) and the second fixing member (520) are combined with the filter (420) in between, the outer surface of the edge area of ​​the filter (420) comes into contact with the inner surfaces of the edge areas of the first fixing member (510) and the second fixing member (520), respectively, and the remaining area of ​​the filter (420) is exposed to the outside by the ventilation portions (512, 522). The overall size of the filter (420) is formed to be somewhat smaller than the size of the first fixing member (510) and the second fixing member (520), and accordingly, in the state of FIG. 15, the filter (420) is not exposed to the side of its plate surface between the two fixing members (510, 520).

[0078] FIG. 16 is a drawing similar to FIG. 10 showing the filter assembly of FIG. 15 mounted between frame members (100, 200), and FIG. 17 is a drawing similar to FIG. 13 showing a cross-section of the filter assembly of FIG. 15 mounted.

[0079] In FIG. 10 and FIG. 13 of the first embodiment described above, a filter (400) is mounted between the pellicle frame members (100, 200), but in the second embodiment, a filter assembly in the state shown in FIG. 15, which includes a filter (420) and a filter fixing member (500), is mounted between the frame members (100, 200). In the first embodiment, as the filter (400) has a tubular shape, the cross-sectional shape of the receiving groove (120) formed in the frame members (100, 200) and both ends (122) has a partial arc shape to partially accommodate the tubular filter (400), but in the present embodiment, as the filter assembly has a rectangular cross-sectional shape overall, the cross-sectional shape of the receiving groove (120) and both ends (122) also has a shape capable of partially accommodating the filter assembly with such a rectangular cross-sectional shape. As shown in FIG. 17, the remaining area of ​​the filter (420), excluding the edge area, is positioned in an upright direction within the ventilation hole (330) by means of the ventilation portions (512, 522). Accordingly, the plate surface of the sheet-shaped filter (420) blocks the ventilation hole (330), so that air passing through the ventilation hole (330) is filtered by the filter (420).

[0080] According to this second embodiment, a filter assembly combining a filter (420) and a filter fixing member (500) is manufactured separately, and the pellicle frame is completed by mutually combining the two frame members (100, 200) while the filter assembly is placed at the location of the ventilation hole (330) between the first frame member (100) and the second frame member (200). Unlike the first embodiment, a flexible filter (400) is not used in the assembly process, and a filter assembly having rigidity by being wrapped by the filter fixing member (500) is used in the assembly process, so the workability in the assembly process is greatly improved.

[0081] Various variations of this second embodiment are described below. In the following variations, the description of configurations identical to the basic configuration of the second embodiment described above is omitted and references are used.

[0082] FIGS. 18 to 21 are drawings illustrating a first variation of a second embodiment of the present invention.

[0083] Compared to the basic configuration of the second embodiment, the first variant differs in that a receiving portion (514, 524) is formed on the inner surface of the fixing member (510, 520), that is, on the surface in contact with the filter (420). The receiving portion (514, 524) is formed by being recessed in the edge area of ​​the surface in contact with the filter (420), and is formed so that its size and shape match the size and shape of the filter (420). Accordingly, the edge area of ​​the filter (420) is received within the receiving portion (514, 524). The filter (420) is installed to be wrapped between the two fixing members (510, 520) by this receiving portion (514, 523). The receiving portion (514, 524) may be formed on only one of the two fixing members (510, 520).

[0084] FIGS. 22 to 26 are drawings illustrating a second variation of a second embodiment of the present invention.

[0085] Compared to the basic configuration of the second embodiment, the second modified embodiment differs in that a recess (526) and a protrusion (516) are formed on the inner surface of the fixing member (510, 520), that is, on the surface in contact with the filter (420). The protrusion (516) is formed at a position adjacent to both ends in the longitudinal direction of the first fixing member (510), and the recess (526) is formed at a position adjacent to both ends in the longitudinal direction of the second fixing member (520). The protrusion (516) and the recess (526) are joined by mutual fitting, and accordingly, the first fixing member (510) and the second fixing member (520) are joined together.

[0086] As shown in FIG. 25, the filter (420) has a length that covers the two protrusions (516) of the first fixing member (510). Accordingly, when the protrusions (516) are inserted into the recess (526), ​​parts of both ends of the filter (420) are drawn into the recess (526) as shown in FIG. 26, thereby fixing the position of the filter (420).

[0087] Meanwhile, in FIG. 25, the vertical length of the protrusion (516) is shown as being smaller than the vertical width of the filter (420). However, the vertical length of the protrusion (516) can be configured to be equal to or greater than the vertical width of the filter (420). In this case, the vertical length of the recess (526) is also equal to or greater than the vertical width of the filter (420), so the entire vertical area at the left and right ends of the filter (420) can be inserted into the recess (526). Accordingly, the insertion and coupling operation of the protrusion (516) and the recess (526) can be easily performed, and the filter (420) can be accurately fixed at a pre-set position.

[0088] FIGS. 27 to 30 are drawings illustrating a third variation of the second embodiment of the present invention in a manner similar to FIGS. 22 to 25, respectively.

[0089] Compared to the second variant, the third variant differs in that a receiving portion (514, 524) is formed on the inner surface of the fixing member (510, 520), that is, on the surface in contact with the filter (420). This third variant corresponds to a configuration that combines the first variant and the second variant described above. The configuration and function of the receiving portion (514, 524) are the same as those described for the first variant. When the receiving portion (514, 524) is formed as in the third variant, the length of the filter (420) is configured to be shorter than in the case of the second variant so that the entire edge of the filter (420) is received within the receiving portion (514, 524). In the third variant as well, only one of the two receiving portions (514, 524) may be formed.

[0090] Meanwhile, in the second embodiment and its variations described above, an adhesive may be applied between the filter (420) and the fixing member (510, 520) so that the filter (420) is fixed to the fixing member (510, 520) by the adhesive force of the adhesive. The adhesive may be applied only between the filter (420) and the fixing member (510, 520).

[0091] In the basic configuration of the second embodiment, it is preferable to use an adhesive. Furthermore, in this basic configuration, it is preferable to use an adhesive between the filter (420) and the first fixing member (510) and between the filter (420) and the second fixing member (520). However, in the first and third variations, the filter (420) is received within the receiving portion (514, 524), and in the second variation, the filter (420) is fixed in position by the combination of the protrusion (516) and the recess (526), ​​so it is acceptable not to use an adhesive in these variations. In the first and third variations, if an adhesive is used, the adhesive may be applied to the recessed bottom surface of the receiving portion (514, 524). In the second variation, if an adhesive is used, the adhesive may be applied within the recess (526).

[0092] Although the present invention has been described above with reference to the drawings, the presented structure is used merely for the purpose of illustrative explanation of the present invention and is not intended to limit the meaning or the scope of the present invention as described in the claims. Therefore, those skilled in the art will understand that various modifications and equivalent alternative structures are possible from the structure, and the true scope of protection of the present invention should be determined by the claims. Explanation of the symbols

[0094] 10: Support part 20: Membrane 30: Pellicle 80: Pellicle assembly 100: First frame member 110: Recess 120: Receiving groove 122: Both ends of the receiving groove 150: Recess 180: Pin groove 200: Second frame member 250: Protrusion 300: Pellicle frame 330: Ventilation hole 400: Filter 420: Filter 500: Filter fixing device 510: First fixing member 512: First ventilation part 514: First receiving part 516: Protrusion 520: Second fixing member 522: Second ventilation part 524: Second receiving part 526: Recess

Claims

Claim 1 delete Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 A pellicle frame used for mounting a pellicle on a photomask by attaching a pellicle having a membrane for transmitting exposure light and a support portion supporting the outer edge region of the membrane, wherein the pellicle is formed in a shape corresponding to the support portion, and the plate surfaces are mutually coupled so as to form a two-layer structure by overlapping, and each having a recess formed in mutually corresponding portion regions of each inner surface facing each other to form a ventilation hole that is opened from the side of the plate surface in a mutually coupled state; and a filter interposed within the ventilation hole between the pair of frame members to block the ventilation hole, and arranged along the longitudinal direction within the recess and having a tubular shape; wherein the thin film of the filter is arranged in a double layer in the direction in which air flows in / out through the ventilation hole due to the cross-sectional structure of the tubular filter. Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 A pellicle frame used for mounting a pellicle on a photomask by attaching a pellicle having a membrane for transmitting exposure light and a support portion supporting the outer edge region of the membrane, wherein the pellicle is formed in a shape corresponding to the support portion, and the plate surfaces are mutually coupled so as to form a two-layer structure by overlapping, and each having a recess formed in mutually corresponding portion regions of each inner surface facing each other to form a ventilation hole that is opened from the side of the plate surface in a mutually coupled state; and a filter interposed within the ventilation hole between the pair of frame members to block the ventilation hole; wherein the filter is fixed to a filter fixing member and the filter fixing member is installed between the pair of frame members so as to be disposed within the ventilation hole, and the filter fixing member has a ventilation portion that partially exposes the filter so as to block the ventilation hole by the filter. Claim 16 A pellicle frame according to claim 15, wherein the filter has the shape of a sheet that extends in a horizontal direction and is arranged with its plate surface in an upright position, and the filter fixing member includes a pair of fixing members each coupled to the filter on both sides of the filter, and each of the fixing members has the ventilation portion formed in the inner region of its edge region. Claim 17 A pellicle frame according to claim 16, characterized in that at least one of the fixing members has a receiving portion formed by a recess in the edge region of the surface in contact with the filter so as to receive the filter. Claim 18 A pellicle frame according to claim 17, characterized in that a recess is formed in one of the fixed members and a protrusion is formed in the other of the fixed members, and a pair of the fixed members are joined together by mutual fitting of the recess and the protrusion. Claim 19 A pellicle frame according to claim 18, wherein the above-mentioned recess and the above-mentioned protrusion are mutually coupled in a state in which a part of the filter is inserted into the above-mentioned recess. Claim 20 A pellicle assembly characterized by comprising: a pellicle frame having a structure as described in any one of claims 8, 15 to 19; and a pellicle attached to the pellicle frame.

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