JP2006178434A - Large pellicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a large pellicle having a deformation range preventing a pellicle film from touching a substrate on blowing air. <P>SOLUTION: The large pellicle 21 comprises a large pellicle frame 23 having ≥1,000 mm diagonal inner size, a large pellicle film 22 stretched with an adhesive 26 over one edge face of the large pellicle frame 23, a pressure-sensitive adhesive 24 applied on opposite edge face to the edge face where the large pellicle film 22 is stretched, so as to stick the frame to a mask, and a liner to protect the adhesive, layered in this order, wherein the deformation degree representing deforming tendency of the large pellicle frame 23 is specified to ≤4.2 mm/N. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a large pellicle, and more particularly, when a thin film transistor (TFT) or a color filter (CF) constituting a liquid crystal display (LCD) is manufactured, foreign matter adheres to a photomask used in a lithographic process. The present invention relates to a large pellicle for prevention.

  2. Description of the Related Art Conventionally, in a lithographic process when manufacturing a TFT constituting an LCD, dust prevention means called a pellicle is placed on a photomask to prevent foreign matter from adhering to the photomask. In recent years, with the increase in size of LCDs, masks for manufacturing LCDs and pellicles for protecting the masks are also increasing in size.

  In such a large pellicle, when the foreign matter adhering to the pellicle film is removed by air blow during use or storage, the problem that the film comes into contact with the mask pattern formed on the photomask has been clarified. . A mask pattern of several μm formed of chromium or chromium oxide on a glass substrate such as quartz may be destroyed by static electricity. For this reason, it is not preferable that the resin pellicle film that may generate static electricity comes into contact with the mask pattern.

  When the deformation amount of the pellicle frame due to the tension of the pellicle film is large, the tension is loosened as a result. The following techniques are available as countermeasures for deformation of the large pellicle frame. First, taking into account the tension of the large pellicle film in order to secure an effective exposure area, the width of the long side of the large pellicle frame for supporting the stretched large pellicle film is larger than the width of the short side, This is a method of suppressing the bending of the long side of the frame body due to pellicle film stretching (for example, Patent Document 1). Moreover, it is a method of forming a pair of sides so as to protrude toward the outside of the frame body, thereby suppressing bending toward the inside of the long side of the frame body due to pellicle film expansion (for example, Patent Document 2).

  As a method of applying initial strain, that is, tension to the pellicle film, there is a method of uniformly extending the pellicle film using a support frame for peeling the pellicle film from the substrate surface (for example, Patent Document 3).

For a pellicle film having an area of 144 cm ² or more, there is a method of providing a pellicle in which the pellicle frame is not deformed and the pellicle film does not wrinkle or sag (for example, Patent Document 4). Specifically, as a method for suppressing the deformation of the pellicle frame, a method for heating the pellicle film to relieve the tension of the pellicle film is described.

JP 2001-109135 A JP 2002-296863 A JP 10-339944 A JP-A-11-65092

  However, the techniques of Patent Document 1 and Patent Document 2 control the deformation of the frame, and are insufficient for preventing the deformation of the pellicle film by air blow.

  In addition, since the purpose of the technique of Patent Document 3 is to produce a pellicle film free from wrinkles and slack, its tension is not always sufficient for preventing deformation by air blow, particularly for a large pellicle.

  In addition, in the example of Patent Document 4, only a pellicle frame having an outer dimension of 120 mm square and a width of 2 mm (inner diameter diagonal dimension is 164 mm) is mentioned, and the rigidity of the pellicle frame and the pellicle film There is no description regarding the relationship of initial strain. Specifically, heating the pellicle film to relieve the tension of the pellicle film does not provide the effect of preventing deformation by air blow even if a pellicle film without wrinkles or sagging can be produced.

  As described above, in the prior art, it is difficult to sufficiently suppress the deformation of the pellicle film due to air blow as the size of the large pellicle increases. This is because sufficient tension is applied to the pellicle film so that the pellicle film does not come into contact with the substrate by air blow, and when the frame is attached to the pellicle frame, the frame itself bends due to the tension, which is substantially It seems to be a major factor that the tension cannot be reduced and the displacement of the pellicle film due to air blow cannot be sufficiently suppressed.

  An object of the present invention is to provide a large pellicle having a deformation range in which the pellicle film does not contact the substrate during air blowing by appropriately controlling the degree of displacement of the pellicle frame and the initial strain of the film. .

  The present invention has been completed as a result of earnestly examining the conditions of the frame body in which it is difficult for the frame body to be deformed according to the initial strain amount and tension required to give sufficient tension. That is, the present invention has the following configuration.

(1) A large pellicle frame having an inner diameter of 1000 mm or more, a large pellicle film stretched on one edge surface of the large pellicle frame via an adhesive, and the large pellicle film stretched In a large pellicle in which an adhesive material provided for adhering to a mask on an edge surface opposite to the edge surface and a liner for protecting the same are laminated in order, the large pellicle frame body is easily deformed. A large pellicle having a displacement degree of 4.2 mm / N or less.

(2) The large pellicle according to (1), wherein an initial strain is applied to the pellicle film in advance and tension is applied when the pellicle film is bonded to the pellicle frame through an adhesive.

(3) The degree of distortion representing the magnitude of the initial strain is 0.7 × 10 ^{−3 to} 3.3 × 10 ⁻³ N / mm, as described in (1) or (2) above Large pellicle.

  The present invention has the configuration as described above. Then, the frame body is prevented from being easily bent by the initial distortion of the pellicle film, and the pellicle film tension is prevented from being loosened. For this reason, it is possible to suppress the film from being easily deformed by air blow. Thus, when air is blown to the pellicle film, it is possible to prevent the pellicle film from coming into contact with the substrate below the pellicle film. Specifically, the amount of deformation of the pellicle film in the mask direction when air is blown to the pellicle film can be reduced to 7 mm or less.

  Hereinafter, a large pellicle frame according to the present invention will be described with reference to the drawings. In addition, this invention is not limited to these. FIG. 1 is a perspective view of a large pellicle, and FIG. 2 is a cross-sectional view of the large pellicle.

  As shown in FIGS. 1 and 2, a pellicle 21 according to the present embodiment includes a large pellicle frame body 23 having a diagonal dimension of 1000 mm or more and an adhesive 26 on one edge surface of the large pellicle frame body 23. A large pellicle film 22 stretched through the adhesive, an adhesive material 24 provided for adhering to the mask on the edge surface opposite to the edge surface on which the large pellicle film 22 is stretched, and a protective liner 25 for protecting it Consists of.

  Further, as shown in FIG. 1, the large pellicle frame body 23 has a long side 23 a constituting the frame body 23 and a short side 23 b constituting the frame body 23.

(Detailed configuration of pellicle film and manufacturing method of pellicle film)
Examples of polymers constituting the pellicle membrane 22 include cellulose derivative polymers such as nitrocellulose, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose propionate, cellulose acetate butyrate, ethyl cellulose, cyanoethyl cellulose, and cellulose carbonate; Pullulan derivative polymers such as fluorinated pullulan and cyanoethyl pullulan; polylactic acid polymer; polyvinylidene fluoride, tetrafluoroethylene-vinylidene fluoride copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene -Perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymer, chlorotrifluoroethylene-vinylidene fluoride copolymer or polyvinyl fluoride, containing a ring structure in the main chain Fluoropolymers such as fluorine polymers (CYTOP (trade name, manufactured by Asahi Glass Co., Ltd.), TEFLON AF (trade name, manufactured by DuPont); polyvinyl acetal polymers such as polyvinyl butyral and polyvinyl propional; 4-methyl-1- A pentene copolymer or the like can be used. The molecular weight of the polymer is selected in consideration of the strength of the pellicle film 22, the elastic modulus, durability against exposure light, solubility in a solvent, and the like.

  Solvents that dissolve these include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester solvents such as ethyl acetate, butyl acetate, and ethyl lactate; alcohol solvents such as methanol, ethanol, isopropanol, and butanol; propylene glycol Monomethyl ether acetate; perfluoroalkylamine (FLUORINERT series (made by 3M, trade name), CT-Solv series (trade name, made by Asahi Glass Co., Ltd.)), perfluoroalkyl furan (FLUORINERT series (made by 3M, product) Name)), hydrofluoroether (Novec series (manufactured by 3M, trade name)), perfluoroether (GALDEN (manufactured by SOLVAY SOLEXIS, trade name)), hydrofluoroether (H-GALDEN (manufactured by SOLVAY SOLEXIS, Fluorine solvents such as product name)) You can use. These solvents may be used alone or in combination.

  The combination of polymer and solvent is a concentration-viscosity characteristic that is optimal for film formation, taking into account solubility so that filtration can be performed with a desired diameter to remove foreign substances and gels, and obtaining a desired pellicle film thickness. Select with consideration of evaporation rate.

  The pellicle film 22 may be a single layer or may be a multilayer film formed by laminating polymers having different refractive indexes in order to increase the light transmittance.

  The polymer is dissolved in a solvent by means of heating, pressurization, stirring, etc. to obtain a polymer solution.

  The polymer solution is pressure filtered with dry air, an inert gas such as nitrogen, or a pump to remove foreign substances and gel in the solution. Filters used for filtration include membrane filters and depth filters made of ethylene tetrafluoride, ultrahigh molecular weight polyethylene, nylon, and polypropylene.

  A polymer solution is dropped onto a film formation substrate, and a film is formed so that a pellicle has a desired film thickness. Examples of the film forming method include a rotational film forming method (spin coating method), a slit coating method, and a slit and spin method.

  As the substrate for film formation, a substrate obtained by polishing and cleaning the surface of quartz glass, low expansion glass, soda glass, ceramics, or the like can be used. Examples of the polishing method include physical polishing and chemical polishing. The surface of the glass may be subjected to a surface treatment in order to control the wettability of the polymer solution and the peelability of the film after drying. Examples of the surface treating agent include a silicone compound having a perfluoroalkyl group and silazane.

  The concentration, viscosity, and boiling point of the solvent are appropriately selected so that the film thickness of the pellicle becomes a desired value. Furthermore, in the rotation film formation method and the slit and spin method, the number of rotations, the rotation time, the rotation acceleration time, and in the slit coating method and the slit and spin method, the solution discharge amount, the interval between the slits, the movement speed of the slit, and the film formation with the slit Adjust the distance to the substrate.

  After the film formation, the solvent is evaporated by drying. Examples of the drying method include a hot plate, an infrared lamp, and a clean oven.

  The film is peeled off from the dried substrate. Adhesive such as double-sided tape or epoxy is applied or applied to a metal temporary frame or resin temporary frame whose outer shape is almost the same shape as the substrate, width is about 10 to 50 mm, and thickness is about 3 to 20 mm. Press and fix to the upper membrane. This frame is gently raised and the film is peeled off from the substrate onto the temporary frame.

  As the material of the pellicle frame 23, aluminum alloy, tool steel, stainless steel, ceramics, glass, or the like can be used. The surface of the pellicle frame 23 may be shot blasted with stainless steel beads or glass beads so that the foreign matter inspection light on the mask does not reflect on the surface of the pellicle frame 23. Also, in order to facilitate the inspection of foreign matter on the surface of the pellicle frame 23, blackening treatment (for example, black alumite treatment by dye or secondary electrolytic coloring, black chrome treatment, etc.) is performed by a method appropriate for each material. good.

  In order to prevent swelling and dent of the film after the pellicle is attached to the mask, the pellicle frame body 23 may be provided with one or a plurality of vent holes. Attach a filter made of ethylene tetrafluoride or the like to prevent foreign matter from entering the vent.

  An acrylic or silicone adhesive may be applied to the inner wall surface of the pellicle frame body 23.

  On one edge surface of the pellicle frame body 23, an adhesive material for adhering to the mask is installed. As the adhesive material, a double-sided tape having an adhesive on both sides of the base material, which is punched out in substantially the same shape as the pellicle frame body 23, is attached, or a hot-melt adhesive material is applied onto the pellicle frame body 23. In order to prevent dust generation from the side surface of the double-sided tape, an adhesive may be applied to the side surface of the base material.

  In order to protect the adhesive surface until it is applied to the mask, a polyester film that has been surface-treated so as to be easily released from the adhesive material is attached to the adhesive material.

  Next, an adhesive is applied to the other edge surface of the pellicle frame 23, and a film stretched on the temporary frame is bonded. Examples of the adhesive include UV (ultraviolet) curable resins such as urethane acrylate, epoxy resins, and fluorine polymers dissolved in a solvent. After pasting, they are bonded by a method suitable for each adhesive, such as heating by UV irradiation, infrared rays or laser irradiation.

  After the film is adhered, the film is cut and removed along the outer periphery of the pellicle frame body 23. Examples of the cutting method include cutting with a blade or the like and dropping of a solvent for dissolving the pellicle film 22.

  In this way, a large pellicle is completed.

(Pelicle membrane frame displacement)
The tension of the pellicle film 22 necessary for suppressing displacement due to air blow can be given by strain generated by stretching the pellicle film 22 before the pellicle film 22 is spread on the pellicle frame body 23, that is, initial strain. On the other hand, it is necessary to increase the rigidity of the frame body 23 in order to make it difficult to deform the frame body 23 against this initial strain. The rigidity of the frame body 23 can be expressed by a displacement degree δ which is the following variable.

  The displacement degree δ is the state of only the frame body 23 where the pellicle film 22 is not extended, and the amount of deformation of the long side 23a when a load is applied to the center of the long side 23a or the short side 23b, A value that defines the amount of displacement per unit load at the center of the long side when a load is simultaneously applied to the short side 23b.

  Taking into account the data and safety factor of medium and small pellicles with a diagonal size of less than 1000 mm so far, the degree of displacement δ = 4.2 mm / N or less was derived as a necessary condition. In a frame having a degree of displacement greater than this, the deflection of the frame when the film is stretched becomes too large, and the initial distortion of the pellicle film 22 is reduced.

  A specific method for measuring the degree of displacement δ will be described. First, as shown in FIG. 3, the long side 23a side of the pellicle frame body 23 is arranged in parallel to the floor surface, and the center of the lower long side 23a on the floor surface side is supported so that the support member 32 comes into contact with the bottom. At the same time, both ends of the upper long side 23a are supported so that the frame body 23 is not displaced.

  Next, the weight 31 is hung on the center of the upper long side 23a, and the amount of movement at the center of the long side at this time is dll [mm]. Here, dll indicates the amount of movement at the center of the long side of the pellicle frame 23 alone. The weight w [g] of the weight 31 is applied to 100 g, 200 g, 300 g, and 400 g with a unit of about 100 g as a target, and dll for each load is measured. From the above measurement results, a proportional constant ll of a linear expression of dll and w passing through the origin represented by the following formula 1 is determined.

[Equation 1]
dll = ll × w × 9.8 / 1000

  Next, as shown in FIG. 4, the short side 23b side of the pellicle frame body 23 is arranged in parallel to the floor surface, and the center of the lower short side 23b on the floor surface side is supported so that the support member 32 contacts from below, It supports so that the both ends of the upper short side 23b may contact so that the frame 23 may not slip | deviate. Next, the weight 31 is suspended from the center of the upper short side 23b, and the amount of movement at the center of the long side 23a at this time is defined as dls [mm]. Aiming at a unit of about 100 g, the weight w [g] of the weight 31 is loaded with 100 g, 200 g, 300 g, and 400 g, and dls for each load is measured. Based on the above measurement results, the linearity constant ls of dls and w passing through the origin represented by the following formula 2 is determined.

[Equation 2]
dls = ls × w × 9.8 / 1000

  The movement amounts dll and dl at the center of the side where the weight 31 is suspended are positive when the deformation of the long side 23a is concave, and negative when the deformation is convex. The proportionality constants ll and ls [mm / N] are obtained from the above relational expression, and the degree of displacement δ indicating the amount of displacement per unit load when a load is simultaneously applied to the long side 23a and the short side 23b by the following equation (3) I can get it. In the following equation (3), ai and bi are the inner lengths of the long side 23a and the short side 23b of the large pellicle frame 23 shown in FIG.

[Equation 3]
δ = ll + ls × bi / ai

(Strain)
The degree of distortion ε [N / mm] is defined as follows. Measure the outer dimension distance between the center of the frame long side 23a before the pellicle film 22 is stretched, and then measure the outer dimension distance between the center of the frame long side 23a after the pellicle film 22 is stretched. The value divided by 2 is defined as the moving distance dl [mm] at the center of the long side (see FIG. 5). Here, the outer dimension distance between the long sides of the frame body on which the pellicle film 22 is stretched is measured first, and then the outer dimension distance between the centers of the long sides of the frame body is measured after releasing the stretching of the pellicle film 22, Similarly, dl [mm] may be obtained.

  The degree of distortion ε is the ratio of the displacement dl / ai obtained by normalizing dl with the inner dimension of the short side 23b to the displacement degree δ. This shows the relationship between the stretched pellicle film 22 having an initial strain and the rigidity of the frame body 23.

The range of this value was derived from the necessary conditions of 0.7 × 10 ^{−3 to} 3.3 × 10 ⁻³ N / mm in consideration of the data of the medium and small pellicles with a diagonal size of less than 1000 mm. . The degree of distortion ε is expressed by the following equation (4).

[Equation 4]
ε = (dl / ai) × (1 / δ)

  The initial strain of the pellicle film 22 can be suitably obtained by using a spin coat method for forming the pellicle film 22. It can also be obtained by peeling from the substrate for spin coating, if necessary, stretching and applying initial strain, and then stretching the pellicle frame. Specifically, the peeled temporary frame is heated and expanded, or the temporary frame is mechanically evenly expanded in the radial direction. Alternatively, when the pellicle frame body 23 is bonded to the peeled pellicle film 22, the initial strain may be applied by curing the adhesive in a state where the pellicle frame body 23 is pressed against the pellicle film 22 and stretched.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

  Cellulose acetate propionate (CAP 480-20, manufactured by Eastman Chemical Company) was selected as the polymer constituting the pellicle membrane, and ethyl lactate was selected as the solvent to prepare a solution having a solid content concentration of 8% by weight. This solution was pressurized to 0.01 MPa with nitrogen and filtered through a membrane filter having a diameter of 0.1 μm.

  As a film-forming substrate, a soda glass surface having a side of 1400 mm was physically polished, further chemically polished, and washed with pure water. This substrate was dried by heating at 100 ° C. for 2 hours in a clean oven, and then cooled to room temperature. Next, a polyethylene container having an open top with a diameter of 5 cm into which 20 cc of this substrate and hexamethyldisilazane was introduced was sealed in a clean metal box for 30 minutes at room temperature. After the glass substrate was taken out, it was heated at 100 ° C. for 2 hours with a clean oven.

  The glass substrate thus prepared was set on a closed cup type spin coater, about 300 g of the polymer solution prepared previously was supplied onto the glass substrate, and the glass substrate was rotated at 350 rpm for 60 seconds.

  This glass substrate was placed on a hot plate at 60 ° C. for 30 minutes to evaporate the solvent.

  Prepare a temporary frame made of black anodized aluminum and sealed aluminum alloy (6061) with a side of 1396mm, width of 20mm and thickness of 6mm, apply epoxy adhesive, and press and fix to the film on the substrate . After the epoxy adhesive is cured, the frame is gently raised and the film is peeled off from the substrate onto the temporary frame.

  As the pellicle frame 23, an aluminum alloy (5052) with a Young's modulus of 70 [GPa] is used, the inner dimensions (ai × bi) 890.5 mm × 734 mm shown in FIG. 1, outer corner Ro = 10, inner corner Ri = 2, inner diameter Diagonal dimension ci = 1152.4 mm, long side frame width aw = 8 mm, short side frame width bw = 7 mm, height h = 5.2 mm, and a through hole with a diameter of 1.5 mm in the center of each long side Open a total of 2 holes each, and open a hole with a diameter of 2mm and a depth of 2mm at the end of each long side for alumite treatment and 2 holes for a total of 4 holes, and the center of both short sides in the height direction. The processing of cutting a handling groove with a width of 1.5 mm and a depth of 2.3 mm was performed over the entire length of the short side. After the surface of the frame was shot blasted with stainless steel beads, black anodized and sealed were prepared.

  Using this frame body, the relational expressions (Equation 1) and (Equation 2) of the load and displacement of each side are obtained as described above, and the proportionality constant ll = 1.47 mm / N, ls = −0.44 mm. / N was obtained. By substituting these proportionality constants and the inner dimensions into the equation (Equation 3), the degree of displacement δ = 1.1 mm / N was obtained.

  An acrylic adhesive was applied to the inner wall surface of the pellicle frame 23 to a thickness of about 10 μm. A membrane filter made of ethylene tetrafluoride was attached to the vent hole portion with an acrylic adhesive. On one edge of the pellicle frame 23, as a mask adhesive material, a hot melt resin made of SEBS (styrene / ethylene / butylene / styrene block co-association) is 6 mm wide and 1.6 mm high. Application and molding. As a protective liner for protecting the surface of the hot melt resin, a polyester film having a thickness of 0.1 mm and subjected to silicone release treatment was attached.

  A urethane acrylate-based UV curable adhesive was applied to the opposite edge surface of the pellicle frame 23 on which the adhesive material was applied. Thereafter, the pellicle film 22 stretched on the temporary frame was placed and irradiated with ultraviolet rays to cure the ultraviolet curable adhesive, and the membranes were adhered. A large pellicle was made by cutting and removing excess film along the outer edge of the frame.

The outer dimension between the long side centers of the pellicle frame body 23 before the pellicle film 22 was stretched was 750 mm, and the outer dimension between the long side centers of the pellicle frame body 23 after the pellicle film 22 was stretched was 747.7 mm. As a result, the amount of movement between the long side centers of the pellicle frame body 23 was dl = (750−747.7) /2=1.15 mm. Substituting d1 = 1.15 mm, δ = 1.1 mm / N, and ai = 890.5 mm into the equation (Equation 4), the degree of distortion ε = 1.1 × 10 ⁻³ N / mm was obtained.

  Near the center of the membrane, air blow is performed from above with an air gun with a 1 mm aperture under the conditions of pressure 0.15 MPa, distance 5 cm, time 10 sec. The surface of the membrane is illuminated with a high-intensity halogen lamp in a dark room, and the membrane surface is visually observed. It was confirmed that there was no trace of contact with the mask pattern on the glass surface.

As described above, it is possible to provide a large pellicle having a displacement degree of 1.1 mm / N and a distortion degree of 1.1 × 10 ⁻³ N / mm and in which the pellicle film 22 does not contact the mask surface even when a load is applied by an air gun.

  The degree of displacement was achieved by appropriately increasing the width and height of the cross section of the frame and the Young's modulus of the material. For example, stainless steel or tool steel could be used to increase the Young's modulus.

  As in Example 1, a solution for forming the pellicle film 22 was prepared.

  As a substrate for film formation, a soda glass surface having a side of 1600 mm was physically polished, further chemically polished, and washed with pure water. This substrate was dried by heating at 100 ° C. for 2 hours in a clean oven, and then cooled to room temperature. Next, a polyethylene container having an open top with a diameter of 5 cm into which 20 cc of this substrate and hexamethyldisilazane was introduced was sealed in a clean metal box for 30 minutes at room temperature. After the glass substrate was taken out, it was heated at 100 ° C. for 2 hours with a clean oven.

  The glass substrate thus prepared was set on a closed cup type spin coater, about 500 g of the polymer solution prepared previously was supplied onto the glass substrate, and the glass substrate was rotated at 350 rpm for 60 seconds.

  This glass substrate was placed on a hot plate at 60 ° C. for 30 minutes to evaporate the solvent.

  Prepare an aluminum alloy (6061) aluminum frame (6061) with a side of 1438mm, a width of 20mm, and a thickness of 8mm. Prepare a temporary frame, apply epoxy adhesive, and press and fix it on the film on the substrate. . After the epoxy adhesive is cured, the frame is gently raised and the film is peeled off from the substrate onto the temporary frame.

  As the pellicle frame body 23, an aluminum alloy (5052) having a Young's modulus of 70 [GPa] is used, an inner dimension (ai × bi) of 1314 mm × 761 mm, an outer corner Ro = 9, an inner corner Ri = 2, and a pair of inner diameters shown in FIG. Square dimension ci = 1516.8 mm, long side frame width aw = 12 mm, short side frame width bw = 12 mm, height h = 5.6 mm, one through hole with a diameter of 1.5 mm at the center of each long side Open a total of 2 holes, open 2 holes each with a diameter of 2mm and a depth of 2mm for gripping and electrodes at the end of each long side, a total of 4 holes, and in the center of both short sides in the height direction. Processing for cutting a handling groove having a width of 1.5 mm and a depth of 2.3 mm was performed over the entire length of the short side. After the surface of the frame was shot blasted with stainless steel beads, black anodized and sealed were prepared.

  Using this frame, the relational expressions (Formula 1) and (Formula 2) of the load and displacement of each side are obtained as described above, and their proportionality constant ll = 1.09 mm / N, ls = −0.21 mm. / N was obtained. By substituting these proportionality constants and the above-mentioned internal dimensions into the formula (Formula 3), the degree of displacement δ = 0.97 mm / N was obtained.

  An acrylic adhesive was applied to the inner wall surface of the pellicle frame 23 to a thickness of about 10 μm. A membrane filter made of ethylene tetrafluoride was attached to the vent hole portion with an acrylic adhesive. On one edge surface of the pellicle frame 23, a hot melt resin made of SEBS (styrene / ethylene / butylene / styrene block co-association) as a mask adhesive is 3.5 mm in width and 1.4 mm in height. It was applied and molded. As a protective liner for protecting the surface of the hot melt resin, a polyester film having a thickness of 0.1 mm and subjected to silicone release treatment was attached.

  A urethane acrylate-based UV curable adhesive was applied to the opposite edge surface of the pellicle frame 23 on which the adhesive material was applied. Thereafter, the pellicle film 22 stretched on the temporary frame was placed and irradiated with ultraviolet rays to cure the ultraviolet curable adhesive, and the membranes were adhered. A large pellicle was made by cutting and removing excess film along the outer edge of the frame.

The outer dimension between the long side centers of the pellicle frame body 23 before the pellicle film 22 was stretched was 787.8 mm, and the outer dimension between the long side centers of the pellicle frame body 23 after the pellicle film 22 was stretched was 783.7 mm. As a result, the amount of movement between the long side centers of the pellicle frame 23 was dl = (787.8−783.7) /2=2.05 mm. dl = 2.05 mm, δ = 0.97 mm / N, and ai = 1314 mm were substituted into the formula (Formula 4) to obtain a degree of distortion ε = 1.6 × 10 ⁻³ N / mm.

  In the same manner as in Example 1, the protective liner protecting the pellicle mask adhesive thus produced was peeled off and attached to a glass mask having a size of 850 mm × 1400 mm and a thickness of 10 mm and a smooth surface.

  Near the center of the membrane, air blow is performed from above with an air gun with a 1 mm aperture under the conditions of pressure 0.15 MPa, distance 5 cm, time 10 sec. The surface of the membrane is illuminated with a high-intensity halogen lamp in a dark room, and the membrane surface is visually observed. It was confirmed that there was no trace of contact with the mask pattern on the glass surface.

From the above, it was possible to provide a large pellicle having a displacement degree of 0.97 mm / N and a distortion degree of 1.6 × 10 ⁻³ N / mm and in which the pellicle film 22 does not contact the mask surface even when a load is applied with an air gun.

  As the pellicle frame body 23, an aluminum alloy (5052) having a Young's modulus of 70 [GPa] is used, the inner dimensions (ai × bi) 1342 mm × 1122 mm, outer corner Ro = 9, inner corner Ri = 2, and inner diameter pair shown in FIG. A large pellicle was obtained in the same manner as in Example 2 except that the angular dimension ci = 1747.6 mm, the long side frame width aw = 12 mm, the short side frame width bw = 12 mm, and the height h = 5.6 mm.

  Using this frame body, the relational expressions (Formula 1) and (Formula 2) of the load and displacement of each side are obtained as described above, and their proportional constants ll = 1.35 mm / N, ls = −0.35 mm. / N was obtained. By substituting these proportionality constants and the internal dimensions into the equation (Equation 3), the degree of displacement δ = 1.06 mm / N was obtained.

The outer dimension between the long side centers of the pellicle frame body 23 before the pellicle film 22 was stretched was 1149.5 mm, and the outer dimension between the long side centers of the pellicle frame body 23 after the pellicle film 22 was stretched was 1146.7 mm. As a result, the amount of movement between the long side centers of the pellicle frame body 23 was dl = (1149.5-1146.7) /2=1.4 mm. dl = 1.4 mm, δ = 1.06 mm / N, and ai = 1342 mm were substituted into the formula (Formula 4) to obtain a degree of distortion ε = 1.0 × 10 ⁻³ N / mm.

  In the same manner as in Example 1, the protective liner protecting the pellicle mask adhesive material thus obtained was peeled off and attached to a glass mask having a size of 1220 mm × 1400 mm and a thickness of 10 mm and a smooth surface.

  Near the center of the membrane, air blow is performed from above with an air gun with a 1 mm aperture under the conditions of pressure 0.15 MPa, distance 5 cm, time 10 sec. The surface of the membrane is illuminated with a high-intensity halogen lamp in a dark room, and the membrane surface is visually observed. It was confirmed that there was no trace of contact with the mask pattern on the glass surface.

As described above, it was possible to provide a large pellicle having a displacement degree of 1.06 mm / N and a distortion degree of 1.0 × 10 ⁻³ N / mm and in which the pellicle film 22 does not contact the mask surface even when a load is applied with an air gun.

  The present invention can be used for a large pellicle for preventing foreign matter from adhering to a photomask used in a lithographic process.

It is a whole frame view of a large pellicle. It is sectional drawing (AA sectional drawing of FIG. 1) of a large sized pellicle. It is a figure which shows the measuring method of a displacement degree. It is a figure which shows the measuring method of a displacement degree. It is a figure which shows the measuring method of a degree of distortion.

Explanation of symbols

21 ... Large pellicle
22 ... Large pellicle membrane
23 ... Large pellicle frame
23a ... long side
23b ... Short side
24 ... Adhesive
25 ... liner
26… Adhesive
31 ... Weight
32 ... Support member
41 ... Frame before spreading the pellicle film (or frame after removing the pellicle film)
42 ... Frame after the pellicle membrane is stretched (or the frame when the pellicle membrane is stretched)

Claims (3)

A large pellicle frame having an inner diameter of 1000 mm or more, a large pellicle film stretched on one edge surface of the large pellicle frame with an adhesive, and an edge surface on which the large pellicle film is stretched In a large pellicle in which an adhesive material provided for attaching to a mask on an opposing edge surface and a liner for protecting it are sequentially laminated,
A large pellicle having a displacement degree of 4.2 mm / N or less indicating ease of deformation of the large pellicle frame. 2. The large pellicle according to claim 1, wherein an initial strain is applied to the pellicle film in advance and tension is applied when the pellicle film is bonded to the pellicle frame via an adhesive. 3. The large pellicle according to claim 1, wherein a degree of distortion representing a magnitude of the initial strain is 0.7 × 10 ^{−3 to} 3.3 × 10 ⁻³ N / mm.

Images