Pellicle frame and pellicle assembly having the same

Abstract

To provide a pellicle frame that facilitates cleaning and inspection of the pellicle frame, minimizes generation of particles induced in a processing process of a material for manufacturing a filter, and can obtain a sufficient buffer effect for preventing breakage of a membrane against a pressure change in an internal space of the pellicle frame, and to provide a pellicle assembly including the pellicle frame.SOLUTION: The pellicle frame comprises a pair of frame members. Each frame member is formed in a shape corresponding to the support portion of the pellicle, and the frame members are coupled to each other so that the plate surfaces thereof overlap each other to form a two layer structure. A recess may be formed in a corresponding portion of each of the inner surfaces of the pair of pellicle members facing each other. The recessed part forms a vent hole opened to the side of the plate surface in a state where the pair of pellicle members are coupled to each other. A filter is interposed in the vent hole.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a pellicle frame, and more particularly to a pellicle frame used to mount a pellicle on top of a photomask, and a pellicle assembly including this pellicle frame. [Background technology]

[0002] EUV lithography technology, which uses EUV (Extreme Ultra-Violet) exposure light with a wavelength of 13.5 nm, is being developed to create fine patterns. In the lithography process, a photomask is used as the original for patterning. However, if impurities such as particles or foreign matter are present on the photomask, these impurities can absorb or reflect the exposure light, potentially damaging the transferred pattern. Therefore, to prevent impurities from adhering to the photomask surface, a pellicle is attached to the top of the photomask. Recently, as circuit line widths become finer, the size of impurities that can damage patterns is also becoming smaller, making the role of pellicles in protecting the photomask increasingly important.

[0003] FIG. 1 shows a pellicle assembly in which a pellicle is mounted on a frame.

[0004] The pellicle assembly 80 includes a pellicle 30 and a pellicle frame 50 .

[0005] The pellicle 30 includes a rectangular membrane 20 that transmits exposure light and a support 10 for supporting the membrane 20. Generally, the membrane 20 is formed on a silicon substrate, and then the underside of the substrate is etched to form the support 10, thereby fabricating the pellicle 30 having the structure shown in FIG.

[0006] Once the fabrication of the pellicle 30, which includes the membrane 20 and the support 10, is complete, the pellicle frame 50 is attached to the underside of the support 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 step, the pellicle frame 50 is attached to the underside of the support 10. To bond the support 10 and the pellicle frame 50 together, an adhesive is applied to the top surface of the pellicle frame 50. The fabrication of the pellicle assembly 80 is completed when the support 10 of the pellicle 30 is attached to the top surface of the pellicle frame 50.

[0007] The pellicle assembly 80 is attached to the photomask P, thereby mounting the pellicle 30 on the photomask. To bond the pellicle assembly 80 to the photomask P, an adhesive is applied to the lower surface of the pellicle frame 50.

[0008] The pellicle assembly 80 is mounted on the photomask P and used in an exposure tool. The interior of the exposure tool is maintained in a vacuum state during the exposure process, and therefore, before the exposure process is performed, the air inside the exposure tool is exhausted to the outside. At this time, the pellicle 30 is subjected to pressure due to the exhaustion of air from the internal space S of the pellicle assembly 80, or more precisely, the internal space S formed by the pellicle 30, pellicle frame 50, and photomask P. During this process, there is a possibility that the membrane 20, which is an extremely thin film, may be damaged. To prevent this, ventilation holes are formed in the pellicle frame 50.

[0009] 2 is a partially enlarged cross-sectional view of FIG. 1, and particularly shows the detailed structure of pellicle frame 50. Pellicle frame 50 has a columnar cross section and, in plan view, has the shape of a rectangular frame that is open in the vertical direction.

[0010] The pellicle frame 50 has ventilation holes 52 formed through its sidewall. A number of ventilation holes 52 are formed at predetermined intervals in the horizontal direction along the sidewall of the pellicle frame 50. The ventilation holes 52 function to communicate the internal space S formed between the pellicle assembly 80 and the photomask P when the pellicle assembly 80 is attached to the photomask P with the external space. During the process of evacuating the inside of the device, the air in the internal space S is discharged to the outside through the ventilation holes 52. As a result, no pressure difference occurs between the internal space S and the outside of the pellicle assembly 80, preventing damage to the membrane 20.

[0011] In this way, the air vent 52 functions to prevent damage to the membrane 20. However, the air vent 52 may also serve as a passageway through which particles from the outside can flow into the internal space S. Therefore, to prevent particles from flowing in from the outside, a filter 56 is installed in the air vent 52. The filter 56 is installed in the form of a filtering membrane that is arranged in an upright position to block the air vent 52. To install the filter 56, a filter accommodating hole 52a is formed in the center of the air vent 52 so as to penetrate the plate surface of the pellicle frame 50 in the vertical direction, and accommodates the upper and lower regions of the filter 56. The filter 56 is installed in the frame 50 by being inserted through this accommodating hole 52a.

[0012] The air flowing into the internal space S through the vent hole 52 is filtered by the filter 56. This prevents external foreign matter and particles from entering the internal space S.

[0013] In this conventional structure, a processing step must be performed to form the vent hole 52 on the side of the pellicle frame 50 in order to install the filter 56. For example, a process of forming the vent hole 52 by precision drilling is required. Because this process generates particles, a precise cleaning process must be performed after the vent hole 52 is formed to remove particles inside the vent hole 52. However, the vent hole 52 has a very small diameter and is formed to penetrate the side wall of the pellicle frame 50, which has a relatively large width. Therefore, cleaning and inspection of particles remaining inside the vent hole 52 is very difficult.

[0014] Furthermore, in this conventional structure, the filter 56 is installed by passing through the receiving hole 52a and must cross the vent hole 52 to shield it after installation. Therefore, the filter 56 must be processed into a wide, rectangular membrane-like shape with a certain thickness. For this reason, to manufacture the filter 56, it is necessary to prepare a filter material, for example, in the shape of a rectangular prism, and then cut it into thin pieces. This means that the entire outer surface of the filter 56 is made up of surfaces cut by a cutting tool. As a result, the outer surface of the filter 56 becomes covered with particles generated during cutting, and the filter 56, which is installed to prevent particles, ends up becoming a source of particles.

[0015] Furthermore, such a conventional pellicle frame has a drawback in that the stronger the function of the filter 56, the less the membrane 20 can protect against pressure changes in the internal space S. For example, to improve the filtering performance of the filter 56, the filter 56 must have a high density, which increases the strength with which the air vent 52 is airtightly closed. Therefore, if the pressure change in the internal space S is large, the strong blocking power of the filter 56 prevents the air vent 52 from buffering the pressure change, which can lead to damage to the membrane 20. On the other hand, if the density of the filter 56 is reduced to increase the pressure buffering effect through the air vent 52 when the pressure change is large, the filtering performance of the filter 56 will be weakened. Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention has been devised to solve the above-mentioned problems, and an object of the present invention is to provide a method for facilitating cleaning and inspection of a pellicle frame.

[0017] Another object of the present invention is to provide a method for minimizing the generation of particles induced during the processing of a filter material for manufacturing a filter.

[0018] Another object of the present invention is to provide a method that can obtain a sufficient buffering effect to prevent damage to the membrane due to pressure changes in the internal space of the pellicle frame, while also improving the filtering effect. [Means for solving the problem]

[0019] In order to achieve the above-mentioned object, the present invention provides a pellicle frame used to attach a pellicle having a membrane for transmitting exposure light and a support part for supporting the outer edge region of the membrane and to mount the pellicle on a photomask, characterized in that the pellicle frame includes a pair of frame members each formed in a shape corresponding to the support part, and interconnected so that their plate surfaces overlap to form a two-layer structure, with recesses formed in corresponding regions of each opposing inner surface, which form air holes opening to the sides of the plate surfaces when interconnected, and a filter interposed in the air holes between the pair of frame members to block the air holes.

[0020] In the pellicle frame, a plurality of the recesses are formed in each of the frame members to form a plurality of the vent holes.

[0021] The cross-sectional height of the filter is preferably greater than the height of the air vent.

[0022] A receiving groove is formed in the bottom surface of each of the recesses to receive the portion of the filter that contacts the bottom surface.

[0023] The receiving groove is formed along the length of the bottom surface.

[0024] The receiving groove has an arc-shaped cross section, and the filter has a circular outer diameter in cross section.

[0025] Alternatively, the receiving groove may have a cross section that is a partial polygonal shape, and the filter may have an outer shape of the cross section that is the polygonal shape.

[0026] The filter preferably has a tubular shape.

[0027] The receiving groove is formed so that its length in the longitudinal direction is longer than that of the recessed portion.

[0028] Preferably, sections of both ends of the receiving groove that exceed the section where the recess is formed are formed to have a semicircular or polygonal cross section.

[0029] An adhesive may be applied to at least a portion of the receiving groove to provide adhesive strength to the filter.

[0030] At least one of the sides of the pair of frame members is formed with a pin groove that provides a portion into which a pin can be inserted from the outside to grip the pellicle frame.

[0031] Each of the frame members has a joint formed therein that is joined by interfitting.

[0032] The joints are formed between a plurality of the vent holes.

[0033] Meanwhile, according to another embodiment of the present invention, the filter is disposed in the air vent by installing the filter fixture between the pair of frame members while being fixed to a filter fixture, and the filter fixture has an air vent that partially exposes the filter so that the air vent is blocked by the filter.

[0034] Preferably, in this case, the filter has the shape of a sheet extending horizontally with its plate surface arranged in an upright position, the filter fixture includes a pair of fixing members respectively connected to the filter on both sides of the filter, and each fixing member has the ventilation portion formed in the inner region of its edge region.

[0035] In one modification, at least one of the fixing members has a recessed receiving portion formed in the edge region of the surface that contacts the filter so as to receive the filter.

[0036] In another variation, a recess is formed in one of the fixing members and a protrusion is formed in the other of the fixing members, and the pair of fixing members are connected to each other by interfitting the recess and the protrusion.

[0037] The recess and the protrusion are configured to be interconnected with a portion of the filter retracted into the recess.

[0038] According to another aspect of the present invention, there is provided a pellicle assembly comprising: a pellicle frame having the above-described structure; and a pellicle mounted on the pellicle frame. [Effects of the Invention]

[0039] According to the present invention, the pellicle frame is formed by joining two frame members, one above the other, and a vent hole is formed by joining the two frame members, so that cleaning and inspection for particles can be easily performed.

[0040] In addition, because the filter is manufactured by cutting a tubular material to a fixed length in the longitudinal direction, the size of the cut surface in each filter is minimized. Therefore, the generation of particles caused by the cutting process is minimized. Furthermore, in the present invention, because the cut surface is not placed inside the air vent, particles generated on the cut surface do not flow into the internal space of the pellicle through the air vent.

[0041] In addition, in the present invention, the filter is manufactured to have a tubular shape and is arranged along the length of the plate surface of the pellicle frame, so that the vent holes are arranged in a double-blocking form by one filter. Therefore, even if the filter density is low, sufficient filtering effect can be obtained by 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, preventing damage to the membrane.

[0042] Furthermore, when a method is adopted in which the filter is fixed in a filter fixture and the filter fixture is installed in the air hole, the filter assembly process can be easily performed. [Brief explanation of the drawings]

[0043] [Figure 1] FIG. 1 shows a pellicle assembly in which the pellicle is mounted on a frame. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of FIG. [Figure 3] FIG. 1 is an exploded perspective view of a pellicle frame according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a side view of the coupled state of FIG. 3. [Figure 5] FIG. 4 is a top view of the first frame member of FIG. 3. [Figure 6] FIG. 6 is a partial perspective view of FIG. 5. [Figure 7] FIG. 4 is a bottom view of the second frame member of FIG. 3. [Figure 8] FIG. 8 is a partial perspective view of FIG. [Figure 9] FIG. 7 is a partially enlarged view of FIG. [Figure 10] FIG. 10 is a diagram showing a state in which a filter is attached in FIG. 9. [Figure 11] FIG. 11 is an enlarged perspective view of the filter of FIG. 10. [Figure 12] 11A and 11B are diagrams showing a filter blank for fabricating the filter of FIG. 10. [Figure 13] FIG. 5 is a cross-sectional view of the ventilation hole portion in the state of FIG. 4. [Figure 14] FIG. 10 is an exploded perspective view of a filter assembly used in a pellicle frame according to a second embodiment of the present invention. [Figure 15] FIG. 15 is a perspective view of the coupled state of FIG. 14. [Figure 16] 16 is a view similar to FIG. 10 showing the filter assembly of FIG. 15 installed; [Figure 17] 16 is a view similar to FIG. 13 showing the filter assembly of FIG. 15 in a cross-sectional view in an installed state. [Figure 18] FIG. 10 is an exploded perspective view of a filter assembly according to a first modified example of the second embodiment of the present invention. [Figure 19] FIG. 19 is an enlarged view of part A in FIG. [Figure 20] FIG. 19 is an enlarged view of part B in FIG. [Figure 21] 17 is a view similar to FIG. 17 showing the filter assembly of FIG. 18 in a cross section in an installed state. [Figure 22] FIG. 10 is an exploded perspective view of a filter assembly according to a second modified example of the second embodiment of the present invention. [Figure 23] FIG. 23 is an enlarged view of part C in FIG. 22. [Figure 24] FIG. 23 is an enlarged view of part D in FIG. 22. [Figure 25] 23 is a side view showing a state in which a filter is attached to the first fixing member in FIG. 22. FIG. [Figure 26] 23 is a partially enlarged cross-sectional view of the first fixing member and the second fixing member in FIG. 22 in a state where they are mutually coupled. FIG. [Figure 27]23 is a view similar to FIG. 22 showing a filter assembly according to a third variant of the second embodiment of the present invention. FIG. [Figure 28] FIG. 24 is a view similar to FIG. 23 showing a filter assembly according to a third variant of the second embodiment of the present invention. [Figure 29] FIG. 25 is a view similar to FIG. 24 showing a filter assembly according to a third variant of the second embodiment of the present invention. [Figure 30] FIG. 26 is a view similar to FIG. 25 showing a filter assembly according to a third variant of the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0044] The present invention will now be described in detail with reference to the accompanying drawings. In the description of the present invention, a detailed description of the general structure of a pellicle assembly will be omitted, and the content described in the description of the prior art with reference to Figures 1 and 2 will be incorporated by reference into the description of the present invention. In the description of the present invention, the components associated with pellicle 30 and shown in Figures 1 and 2 will be referred to using the same reference numerals.

[0045] A first embodiment of the present invention will be described below with reference to FIGS.

[0046] 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 assembled state of Fig. 3. As described above in the description of the prior art, pellicle 30 comprises a rectangular membrane 20 for transmitting exposure light and a support 10 for supporting the outer edge region of membrane 20, and pellicle frame 300 is mounted on top of photomask P with pellicle 30 attached to its top.

[0047] The pellicle frame 300 of the present invention includes a pair of frame members 100 and 200, that is, a first frame member 100 and a second frame member 200, and further includes a filter 400.

[0048] 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 in which the entire membrane 20 has a rectangular plate shape, with only the edge region remaining and the remainder removed. The shape of the removed portion corresponds to the remaining region of the membrane 20 excluding the region where the support portion 10 is formed, i.e., the window region through which the EUV exposure light passes. As a result, each frame member 100, 200 has a shape in which four thin, long, bar-shaped plates are connected to form a rectangular frame overall. Each frame member 100, 200 is formed as a single member and manufactured in a single molding process.

[0049] The first frame member 100 and the second frame member 200 are connected to each other 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, and they are connected to each other from above and below. The filter 400 is interposed between the two frame members 100 and 200.

[0050] Figures 5 and 6 are views showing the first frame member 100 of Figure 3, and Figures 7 and 8 are views showing the second frame member 200 of Figure 3. Figures 7 and 8 show the second frame member 200 in an upside-down state from the state of Figure 3 in order to clearly show the structure of the second frame member 200.

[0051] A recess 110 is formed on each of the inner surfaces of the frame members 100, 200 that face each other, i.e., 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 a corresponding area of ​​each frame member 100, 200. As a result, when the two frame members 100, 200 are coupled together, the two opposing recesses 110 form an air vent 330 on the side of the plate surface of the pellicle frame 300. The filter 400 is positioned within this air vent 330 to block it. A plurality of recesses 110 are formed in each frame member 100, 200, thereby providing the pellicle frame 300 with a plurality of air vents 330.

[0052] The recesses 110 are formed in a shape recessed to a uniform depth from the plate surface of the frame members 100, 200 over a certain section along the length of each frame member 100, 200. In addition, the recesses 110 are configured to be recessed over the entire section in the width direction of the plate surface of the frame members 100, 200.

[0053] A receiving groove 120 is formed on the bottom surface of the depression 110 so as to be recessed further from the depression 110. The receiving groove 120 is formed along the length of the bottom surface of the depression 110, and both ends 122 thereof are recessed so as to extend outward beyond the section where the depression 110 is formed.

[0054] The receiving groove 120 is formed to have a shape corresponding to the outer shape of the filter 400, specifically, an arc-shaped cross section, in order to partially receive the filter 400. However, the outer shape is not limited to an arc-shaped shape and is determined to match the shape of the filter 400. The cross section of the filter 400 may have a polygonal shape such as a square.

[0055] The filter 400 is disposed in the recess 110 along the length direction, and in an embodiment of the present invention, the outer diameter of the cross section thereof is formed to have a circular shape, more specifically, a tubular shape, as will be described later. As a result, a portion of the filter 400 in contact with the bottom surface of the recess 110 is received in the receiving groove 120. The receiving groove 120 stably maintains the position and fixation of the filter 400 within the air vent 330. Meanwhile, to further strengthen the fixation of the filter 400, an adhesive that provides adhesion to the filter 400 may be applied within the receiving groove 120. The adhesive may be applied to the entire section or a portion of the receiving groove 120. For example, the adhesive may be applied only to both end portions 122 of the entire section of the receiving groove 120, which are not located within the recess 110.

[0056] 9 is a partially enlarged view of FIG. 6, and FIG. 10 is a view showing the state in FIG. 9 where filter 400 has been attached.

[0057] As described above, the receiving groove 120 is formed so that its length in the longitudinal direction is longer than the length of the depression 110 itself. That is, the receiving groove 120 has a concave shape in the bottom surface of the depression 110, but both end portions 122 of the receiving groove 120 extend beyond the section of the depression 110, and these extended end portions 122 are formed by portions that are directly recessed from the plate surfaces of the frame members 100 and 200. The sections of both end portions 122 of the receiving groove 120 that extend beyond the section where the depression 110 is formed are formed to have a semicircular cross section so that they can match the tubular-shaped filter 400.

[0058] 10 , most of the filter 400 is positioned within the recess 110, with portions of both ends of the filter 400 being placed within the semicircular ends 122 of the receiving grooves 120. That is, the cross-sectional height of the filter 400 is configured to be higher than the height of the air vents 330, so that a portion of the upper and lower cross-section of the filter 400 is received within the upper and lower receiving grooves 120, respectively, thereby fixing the position of the filter 400 within the recess 110. When the two frame members 100 and 200 are joined, the air vents 330 formed by the recess 110 are covered by the filter 400, and both ends of the filter 400 are pressed and fixed by the engagement of the semicircular ends 122 of the two receiving grooves 120.

[0059] On the other hand, if the filter 400 is formed to have a polygonal cross section, both ends 122 of the accommodation groove 120 are configured to have a polygonal shape that corresponds to the shape of the filter 400 and accommodates half of the cross section of the filter 400.

[0060] Each frame member 100, 200 is formed with coupling parts 150, 250 that are coupled by interfitting. More specifically, the second frame member 200 is formed with a convex part 250 that protrudes from the inner surface of the second frame member 200 as shown in Figures 7 and 8, and the inner surface of the first frame member 100 is formed with a concave part 150 that is recessed in a shape corresponding to the convex part 250 as shown in Figures 5 and 6, and the pair of convex part 250 and concave part 150 constitutes the coupling parts 150, 250. The first frame member 100 and the second frame member 200 are coupled to each other by the interfitting coupling of the coupling parts 150, 250.

[0061] In this embodiment of the present invention, eight coupling portions 150, 250 are formed at each of the four corners and four sides of the pellicle frame 300. The number of coupling portions 150, 250 can be determined as needed. In the case of coupling portions 150, 250 formed at the corners, they are formed to have an overall "L" shape along the curved surface of the corner. The shapes of the coupling portions 150, 250 can be various as long as they can be detachably coupled by interlocking a protrusion and a recess. The coupling portions 150, 250 are formed in the regions between the respective vent holes 330. As a result, the coupling portions 150, 250 and the vent holes 330 are alternately arranged along the surface of the pellicle frame 300.

[0062] Meanwhile, pin grooves 180 are formed on the outer surfaces of the frame members 100 and 200. Each pin groove 108 is formed at a corresponding position on the first frame member 100 and the second frame member 200, and when the two frame members 100 and 200 are coupled, the two pin grooves 180 form a single hooking groove. The pin grooves 180 provide a location into which an external device can insert a pin to grip the pellicle frame 300. This external device refers to a device that grips the pellicle frame 300, for example, to move the manufactured pellicle frame 300 to a storage location or to attach the pellicle frame 300 to a photomask P. The pin grooves 180 are formed in at least two positions on the pellicle frame 300, particularly two positions on opposite sides, so that the external device can insert a pin into two or more pin grooves 180 to hook the pellicle frame 300. The number and positions of the pin grooves 180 can be varied as needed.

[0063] Figure 11 is an enlarged perspective view of filter 400 of Figure 10. Filter 400 of the present invention has an overall tubular shape. The material of filter 400 can be appropriately selected as needed, and a material having many pores is preferable.

[0064] FIG. 12 illustrates a filter blank for fabricating the filter of FIG. 10. After preparing a very long, tubular filter blank 400a, the filter blank 400a is cut in the direction of the arrow to a predetermined length to obtain each filter 400 as shown in FIG. 11. Because the filter 400 is fabricated by cutting the tubular filter blank 400a in this manner, the cut surfaces of the filter 400 form the surfaces at both ends of the filter 400. As shown in FIG. 10, when the filter 400 is installed, the cut surfaces are positioned within both ends 122 of the receiving groove 120. Therefore, when the first frame member 100 and the second frame member 200 are combined as shown in FIG. 4, the cut surfaces are not positioned within the ventilation holes 330 and are not exposed to the outside. This prevents foreign matter generated on the cut surfaces during the fabrication of the filter 400 from acting as particles.

[0065] FIG. 13 is a cross-sectional view of the ventilation hole 330 in the state shown in FIG.

[0066] When the filter 400 is placed between the two frame members 100 and 200, the cross-sectional structure of the tubular filter 400 results in a double-layered configuration of the thin membranes of the filter 400 in the direction of air inflow / outflow through the vent hole 330. Therefore, due to the double filtering effect, a sufficient filtering effect can be obtained even if the density of the filter 400, i.e., the airtightness of the vent hole 330, is reduced. Furthermore, even if a sudden pressure change occurs between the inside and outside of the pellicle frame 300, the pressure change is buffered by the space inside the tube, i.e., between the double filters, effectively preventing damage to the membrane 20.

[0067] A second embodiment of the present invention will be described below with reference to FIGS.

[0068] In the following description of the second embodiment, detailed description of components that are substantially the same as those in the first embodiment will be omitted, and such components will be incorporated as components of the second embodiment. For ease of illustration and description, the same reference numerals will be used to refer to such substantially identical components.

[0069] 14 to 17 are diagrams showing the basic configuration of the second embodiment of the present invention.

[0070] The second embodiment differs from the first embodiment in that a filter assembly including a filter 420 and a filter fixture 500 is used instead of the filter 400. That is, the filter 420 is not installed alone in the air vent 330, but is prepared as a filter assembly fixed in the filter fixture 500 and then installed in the air vent 330. The following description will describe the configuration of the filter assembly.

[0071] FIG. 14 is an exploded perspective view of a filter assembly used in a pellicle frame, and FIG. 15 is a perspective view of the filter assembly in the coupled state shown in FIG.

[0072] In this embodiment, the filter 420 has an overall rectangular sheet shape, and this sheet extends horizontally with its plate surface standing upright. The filter fixture 500 functions to fix the filter 420. That is, the filter 420 is fixed to the filter fixture 500, and in this state, the filter fixture 500 is installed between the pair of frame members 100, 200, thereby placing the filter 420 in the air vent 330.

[0073] The filter fixture 500 includes a pair of fixing members 510, 520 that are respectively coupled 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 of a horizontally long rectangular plate is removed, leaving only the edge region, to form a ventilation portion 512. The second fixing member 520 also has a shape in which only the long rectangular edge region is left, leaving only the edge region, to form a ventilation portion 522 in the inner region. The first fixing member 510 and the second fixing member 520 have substantially the same shape. When the first fixing member 510 and the second fixing member 520 are coupled to each other with the filter 420 sandwiched therebetween, the outer surface of the edge region of the filter 420 contacts the inner surfaces of the edge regions of the first fixing member 510 and the second fixing member 520, respectively, and the remaining region of the filter 420 is exposed to the outside through the ventilation portions 512, 522. The overall size of the filter 420 is formed to be slightly smaller than the sizes of the first fixing member 510 and the second fixing member 520, so that the filter 420 is not exposed to the sides of its plate surface between the two fixing members 510 and 520 in the state shown in Figure 15.

[0074] Figure 16 is a view similar to Figure 10 showing the filter assembly of Figure 15 mounted between each frame member 100, 200, and Figure 17 is a view similar to Figure 13 showing a cross section of the filter assembly of Figure 15 mounted.

[0075] 10 and 13, filter 400 is mounted between each frame member 100, 200 of the pellicle. In the second embodiment, however, a filter assembly including filter 420 and filter fixture 500, as shown in FIG. 15, is mounted between each frame member 100, 200. In the first embodiment, filter 400 has a tubular shape, so the cross-sectional shapes of receiving grooves 120 and both ends 122 formed in each frame member 100, 200 are arc-shaped to partially accommodate the tubular filter 400. In the present embodiment, however, the filter assembly has an overall rectangular cross-sectional shape, so the cross-sectional shapes of receiving grooves 120 and both ends 122 are also shaped to partially accommodate such a rectangular filter assembly. As shown in FIG. 17, ventilation portions 512, 522 allow the remaining area of ​​filter 420, excluding the edge areas, to be positioned upright within ventilation hole 330. As a result, the plate surface of the sheet-shaped filter 420 blocks the air vent 330 , and the air passing through the air vent 330 is filtered by the filter 420 .

[0076] According to the second embodiment, a filter assembly combining the filter 420 and the filter fixture 500 is separately manufactured, and this filter assembly is placed at the position of the air vent 330 between the first frame member 100 and the second frame member 200, and the two frame members 100, 200 are then combined together to complete the manufacture of the pellicle frame. Unlike the first embodiment, the soft filter 400 is not used in the assembly process, but rather the rigid filter assembly wrapped in the filter fixture 500 is used in the assembly process, which greatly improves workability in the assembly process.

[0077] Various modifications of the second embodiment will be described below. In the modifications below, the same components as those in the second embodiment will be omitted from the description and will be referred to using the same reference numerals.

[0078] 18 to 21 are diagrams showing a first modification of the second embodiment of the present invention.

[0079] Compared to the basic configuration of the second embodiment, the first modified example differs in that receiving portions 514, 524 are formed on the inner surfaces of the fixing members 510, 520, i.e., the surfaces that contact the filter 420. The receiving portions 514, 524 are recessed into the edge regions of the surfaces that contact the filter 420, and are formed to match the size and shape of the filter 420. As a result, the edge regions of the filter 420 are received within the receiving portions 514, 524. The receiving portions 514, 524 allow the filter 420 to be installed so that it is enclosed between the two fixing members 510, 520. The receiving portions 514, 524 may be formed on only one of the two fixing members 510, 520.

[0080] 22 to 26 are diagrams showing a second modification of the second embodiment of the present invention.

[0081] Compared to the basic configuration of the second embodiment, the second modified example differs in that protrusions 516 and recesses 526 are formed on the inner surfaces of fixing members 510, 520, i.e., the surfaces that come into contact with filter 420. Protrusions 516 are formed at positions adjacent to both ends in the length direction of first fixing member 510, and recesses 526 are formed at positions adjacent to both ends in the length direction of second fixing member 520. Protrusions 516 and recesses 526 are coupled by interfitting with each other, thereby coupling first fixing member 510 and second fixing member 520 to each other.

[0082] 25, filter 420 has a length that covers both side protrusions 516 of first fixing member 510. As a result, when protrusions 516 are inserted into recesses 526, portions of both ends of filter 420 are pulled into recesses 526 as shown in FIG. 26, and the position of filter 420 is fixed.

[0083] 25 shows that the vertical extension of convex portion 516 is shorter than the vertical width of filter 420. However, the vertical extension of convex portion 516 may be configured to be the same as or greater than the vertical width of filter 420. In this case, the vertical extension of recess 526 is also the same as or greater than the vertical width of filter 420, so that the entire vertical area at the left and right ends of filter 420 can be pulled into recess 526. This facilitates the insertion and coupling of convex portion 516 and recess 526 and allows filter 420 to be accurately fixed in a predetermined position.

[0084] 27 to 30 show, in a manner similar to FIGS. 22 to 25 respectively, a third modification of the second embodiment of the present invention.

[0085] The third modification differs from the second modification in that accommodating portions 514, 524 are formed on the inner surfaces of fixing members 510, 520, i.e., the surfaces that contact filter 420. This third modification corresponds to a configuration that combines the first and second modifications described above. The configuration and function of accommodating portions 514, 524 are the same as those described for the first modification. When accommodating portions 514, 524 are formed as in the third modification, the length of filter 420 is configured to be shorter than in the second modification so that the entire edge of filter 420 is accommodated within accommodating portions 514, 524. In the third modification, only one of the two accommodating portions 514, 524 may also be formed.

[0086] Meanwhile, in the second embodiment and its modified examples described above, an adhesive may be applied between the filter 420 and the fixing members 510, 520 so that the filter 420 is fixed to the fixing members 510, 520 by the adhesive force of the adhesive. The adhesive may be applied only between the filter 420 and one of the fixing members 510, 520.

[0087] In the basic configuration of the second embodiment, it is preferable to use adhesive. Furthermore, in such a basic configuration, it is preferable to use adhesive both 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 housed in the housing portions 514 and 524, and in the second variation, the filter 420 is fixed in position by the connection between the protrusion 516 and the recess 526. Therefore, adhesive need not be used in these variations. In the first and third variations, if adhesive is used, the adhesive may be applied to the recessed bottom surfaces of the housing portions 514 and 524. In the second variation, if adhesive is used, the adhesive may be applied to the recess 526.

[0088] Although the present invention has been described above with reference to the drawings, the structures shown are merely used for the purpose of illustration and description of the present invention, and are not intended to limit the meaning or the scope of the present invention as described in the claims. Therefore, a person skilled in the art of the present invention will understand that various modifications and equivalent alternative structures are possible from the structures. Furthermore, the true scope of protection of the present invention should be determined by the claims. [Explanation of symbols]

[0089] 10: Support part 20: Membrane 30: Pellicle 80: Pellicle assembly 100: First frame member 110: Depression portion 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 tool 510: First fixing member 512: First ventilation section 514: First storage section 516: Protrusion 520: Second fixing member 522: Second ventilation section 524: Second storage section 526: Recess

Claims

1. A pellicle frame used to mount a pellicle having a membrane for transmitting exposure light and a support portion for supporting an outer edge region of the membrane, and to mount the pellicle on a photomask, a pair of frame members each formed in a shape corresponding to the support portion, and interconnected so that their plate surfaces overlap to form a two-layer structure, and each having recessed portions formed in corresponding partial regions of each opposing inner surface to form ventilation holes opening to the sides of the plate surfaces when interconnected; a filter interposed in the vent hole between the pair of frame members to block the vent hole; A pellicle frame comprising:

2. The pellicle frame according to claim 1 , wherein a plurality of said recesses are formed in each of said frame members to form a plurality of said vent holes.

3. 2. The pellicle frame according to claim 1, wherein the height of the filter in cross section is greater than the height of the air vent.

4. 2. The pellicle frame according to claim 1, wherein a receiving groove is formed in the bottom surface of each of the recesses to receive the portion of the filter that contacts the bottom surface.

5. The pellicle frame according to claim 4 , wherein the receiving groove is formed along the length of the bottom surface.

6. The receiving groove has an arc-shaped cross section, 6. The pellicle frame according to claim 5, wherein the filter is formed so that the outer diameter of the cross section thereof has a circular shape.

7. The receiving groove has a cross section that is a partial polygonal shape, The pellicle frame according to claim 5, wherein the filter is formed so that the cross-sectional outer shape thereof has the polygonal shape.

8. The pellicle frame according to claim 5 , wherein the filter has a tubular shape.

9. The pellicle frame according to claim 5 , wherein the length of the accommodation groove along the longitudinal direction is longer than the length of the recessed portion.

10. The pellicle frame according to claim 9 , wherein sections of both ends of the receiving groove that exceed the section where the recess is formed are formed to have a semicircular or polygonal cross section.

11. 5. The pellicle frame according to claim 4, wherein an adhesive is applied to at least a portion of the inside of the accommodation groove to provide adhesive strength to the filter.

12. A pellicle frame described in any one of claims 1 to 11, characterized in that a pin groove is formed on at least one side of the pair of frame members, providing a portion into which a pin can be inserted from the outside to grip the pellicle frame.

13. 12. The pellicle frame according to claim 1, wherein each of the frame members is formed with a joint portion that is joined by interfitting with another.

14. The pellicle frame according to claim 13 , wherein the connecting portion is formed between a plurality of the vent holes.

15. the filter is disposed in the ventilation hole by installing the filter fixture between the pair of frame members while the filter is fixed to the filter fixture; 10. The pellicle frame according to claim 1, wherein the filter fixture has a ventilation portion that partially exposes the filter so that the ventilation hole is blocked by the filter.

16. The filter has a sheet shape that extends horizontally and is arranged with its plate surface upright, the filter fixture includes a pair of fixing members respectively coupled to the filter on both sides of the filter; The pellicle frame according to claim 15, wherein the ventilation portion is formed in an inner region of an edge region of each of the fixing members.

17. The pellicle frame according to claim 16, wherein at least one of the fixing members has a recessed receiving portion formed in the edge region of the surface that contacts the filter to receive the filter.

18. The pellicle frame of claim 17, wherein a recess is formed in one of the fixing members and a protrusion is formed in the other of the fixing members, and the pair of fixing members are interconnected by interfitting the recess and the protrusion.

19. 19. The pellicle frame of claim 18, wherein the recess and the protrusion are interconnected with a portion of the filter retracted into the recess.

20. The pellicle frame according to claim 1 ; A pellicle attached to the pellicle frame A pellicle assembly comprising:

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