Pellicle for EUV exposure

Abstract

[Problem] To provide an easily replaceable pellicle for EUV exposure. [Solution] When a pellicle (10) for EUV exposure in which a pellicle adhesive layer is attached to a substrate made of a material forming the outermost surface of an absorption film of an exposure original plate (1), to which the pellicle (10) is to be attached, is peeled off 90º from the substrate at the speed of 0.1 mm / s, the peeling strength is 30-70 N.

Description

EUV Exposure pellicle 【0001】 The present invention relates to a pellicle attached to a photomask for lithography as dust removal. 【0002】 In recent years, the design rules of LSIs have been miniaturized to sub-quarter microns, and accordingly, the short wavelength of exposure light sources has been progressing. That is, the exposure light source has shifted from g-line (436 nm) and i-line (365 nm) by mercury lamps to KrF excimer lasers (248 nm), ArF excimer lasers (193 nm), etc., and further, EUV (Extreme Ultra Violet) exposure using EUV light with a main wavelength of 13.5 nm is being studied. 【0003】 In the manufacture of semiconductors such as LSIs and super LSIs or the manufacture of liquid crystal display plates, light is irradiated onto a semiconductor wafer or a master plate for liquid crystal to create a pattern. In this case, if dust adheres to the photomask and reticle for lithography (hereinafter collectively referred to as the "exposure master"), this dust absorbs or bends the light, resulting in problems such as the transferred pattern being deformed, the edges being rough, and the substrate being blackened and soiled, which damages the dimensions, quality, appearance, etc. 【0004】 These operations are usually carried out in a clean room, but it is still difficult to always keep the exposure master clean. Therefore, a method of attaching a pellicle to the surface of the exposure master as dust removal and then performing exposure is generally adopted. In this case, foreign substances do not directly adhere to the surface of the exposure master but adhere to the pellicle. Therefore, if the focus is set on the pattern of the exposure master during lithography, the foreign substances on the pellicle become irrelevant to the transfer. 【0005】The basic structure of this pellicle consists of a pellicle film with high transmittance to the light used for exposure stretched across the upper end surface of the pellicle frame, and an airtight gasket formed on the lower end surface. The airtight gasket generally uses an adhesive layer. The pellicle film is made of nitrocellulose, cellulose acetate, fluorine-based polymers, etc., which transmit light used for exposure well (g-line (436 nm), i-line (365 nm) from a mercury lamp, KrF excimer laser (248 nm), ArF excimer laser (193 nm), etc.), but for EUV exposure, ultrathin silicon films and carbon films are being considered as pellicle films. 【0006】 Due to the limitations of the exposure equipment, there are restrictions on the thickness (height) of pellicles used for EUV exposure. Because the space for pellicle placement within the EUV exposure equipment is small, the height of the pellicle must be less than 2.5 mm. Considering the thickness of the pellicle film, the thickness of the adhesive or bonding agent applied to the upper and lower ends of the pellicle frame, and the deflection of the pellicle film that occurs when pressure changes occur inside and outside the pellicle, the thickness of the pellicle frame must be less than 2.5 mm. 【0007】 The pellicle attached to the exposure plate is replaced if any problems occur, such as film deterioration or the attachment of foreign matter. The pellicle replacement process involves inserting a peeling jig into a jig hole in the pellicle frame and lifting it to detach the pellicle from the exposure plate. After that, the mask is cleaned and restored, and the pellicle is reattached to replace the pellicle. 【0008】 Patent Document 1 discloses an engagement mechanism that provides a removable and engageable attachment between a patterning device (mask) and a pellicle frame, particularly in a mask assembly used in an EUV lithography apparatus. 【0009】Patent Document 2 discloses a method for removing a pellicle from a photomask, wherein the photomask, which has a pellicle attached to the photomask by a plurality of microstructures, is placed on a pellicle holder, and the plurality of microstructures are removed from the photomask by applying force or energy to the plurality of microstructures before or without applying a tensile force to separate the pellicle from the photomask, thereby removing the plurality of microstructures from the photomask and removing the pellicle from the photomask. 【0010】 Patent No. 6769954 Publication Special Publication No. 2022-22202 【0011】 As mentioned earlier, ultrathin silicon films and carbon films are being considered as pellicle films for EUV lithography. These films tend to break into tiny fragments when damaged, and these fragments scatter, contaminating the surrounding environment. Furthermore, because the fragments scatter, it is difficult to pinpoint the source of the contamination. On the other hand, conventional pellicle films for semiconductors and liquid crystals, such as ArF and KrF, are made of fluororesin and cellulose, respectively, and are ductile, resulting in an extremely low risk of breakage. 【0012】 Reducing the risk of damage to the pellicle film during the replacement process of the pellicle attached to the exposure plate is a challenge unique to EUV pellicles. The greatest force is applied to this pellicle film when the pellicle is peeled off the mask. 【0013】 In EUV lithography, the pellicle needs to be peeled off more frequently than in conventional ArF or KrF lithography. This is because EUV films have poor durability against EUV light, requiring frequent pellicle replacement. If the pellicle film is damaged and contaminated with each frequent replacement, it takes time to regenerate the mask, severely reducing product production efficiency. 【0014】 Therefore, EUV lithography requires pellicles that are easier to replace than those used in conventional methods. 【0015】Normally, the pellicle is fixed to the mask by a mask adhesive provided on the lower end surface of the pellicle frame. However, Patent Document 1 presents a method of fixing the pellicle frame and the mask with an engagement mechanism to facilitate pellicle replacement. With this fixing method, if there is a problem with the pellicle film, the pellicle film can be replaced simply by detaching the pellicle frame from the engagement mechanism. However, this fixing method had the potential to generate dust when detaching the engagement mechanism. Also, if there was a problem with the mask, it was necessary to remove the engagement mechanism (stud) fixed to the mask, which was a very complicated process. 【0016】 Patent Document 2 presents a structure in which a microstructure is placed between the mask adhesive and the mask to facilitate the removal of the pellicle from the mask. By applying force or energy to the microstructure during removal and deforming its shape, the pellicle can be easily removed. However, the width of the pellicle frame is generally 5 mm or less, and the width of the mask adhesive provided on the lower end surface of the frame is inevitably the same as or narrower than the frame width. It was extremely difficult to place a microstructure directly beneath such a narrow mask adhesive without causing foreign matter to adhere. Furthermore, there were concerns that the microstructure might begin to deform during exposure, causing the pellicle to fall off, and also concerns about gas emission from the microstructure. 【0017】 The object of the present invention is to provide an easily replaceable EUV exposure pellicle that maintains the method of fixing the pellicle to the mask with a mask adhesive, similar to conventional pellicles for KrF exposure and ArF exposure, that is, maintains the same mask fixing mechanism as conventional pellicles, and does not require the introduction of special equipment, and allows the application of conventional mask regeneration (cleaning) methods. 【0018】 The inventors of the present invention have found that the above problem can be solved by setting the peel strength when peeling off a pellicle, which is attached to a substrate made of a material that forms the outermost surface of the absorption film of an exposure plate used in an EUV exposure apparatus, from the substrate to a certain range, and have completed the present invention. 【0019】In other words, the present invention is as follows: [1] An EUV exposure pellicle used in EUV lithography, characterized in that the peel strength of the EUV exposure pellicle, which has an adhesive layer of the EUV exposure pellicle attached to a substrate made of a material that forms the outermost surface of the absorption film of an exposure plate to which the EUV exposure pellicle is attached, is 30N to 70N when the EUV exposure pellicle is peeled off from the substrate at a speed of 0.1 mm / s at a 90-degree angle. [2] The EUV exposure pellicle according to [1], wherein the substrate contains at least one metal element selected from Ru, Ta, Cr, Rh, Mo, Nb, Ti, Zr, Y, Si, Pd, Ag, Pt, Au, Ir, W, Co, Mn, Sn, V, Ni, Fe, Hf, Cu, Te, Zn, Mg, Ge, Re, and Al. [3] The EUV exposure pellicle according to [2], wherein the substrate contains at least one nonmetallic element selected from oxygen, nitrogen, carbon, and boron. [4] An exposure master plate with a pellicle, characterized in that the EUV exposure pellicle according to any one of [1] to [3] is installed on the exposure master plate. [5] An exposure method characterized by exposure using the EUV exposure pellicle according to any one of [1] to [3]. [6] A method for manufacturing a semiconductor, characterized by comprising the step of exposure using the EUV exposure pellicle according to any one of [1] to [3]. 【0020】 According to the present invention, it is possible to provide a pellicle for EUV exposure that is easy to replace. 【0021】 This is a longitudinal cross-sectional view showing the state in which a pellicle has been attached to the exposure master plate. This is a schematic perspective view of a pellicle peeling device according to one embodiment. This is a schematic diagram of a uniaxial robot of a pellicle peeling device according to one embodiment. 【0022】 Embodiments of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to these embodiments. In each drawing, the same or corresponding parts are denoted by the same reference numerals. Furthermore, the photomask (hereinafter sometimes simply referred to as "mask") described below is an example of an exposure master plate, and the same applies to the reticle. 【0023】As shown in Figure 1, the pellicle 10 for EUV exposure of the present invention has a basic configuration comprising a pellicle frame (frame body) 11, a pellicle film 12 stretched over one end face of the pellicle frame 11 (the upper surface in Figure 1) via a pellicle film adhesive (adhesive layer) 13 to close the frame opening, and a mask adhesive (adhesive layer) 14 provided on the other end face of the pellicle frame 11 (the lower surface in Figure 1) for peeling off and attaching to the pattern surface of the exposure master 1. In addition, a ventilation through hole 15 and a filter 16 can be provided at its opening. 【0024】 In the EUV exposure pellicle of the present invention, the pellicle frame is typically a rectangular (or square) frame having an upper end surface on which the pellicle film is provided and a lower end surface facing the photomask. However, it does not need to be a perfectly rectangular frame, and each side of the rectangular frame may have a partially protruding portion. For example, when using an image alignment function to position the pellicle frame, the frame needs structurally distinctive markers. In this case, a partially protruding portion may be provided on the outside or inside of the edge as a marker for positioning. It is preferable to provide the protruding portion on the outside of the frame so as not to obstruct the exposure area. 【0025】 Furthermore, the pellicle frame has a surface for attaching the pellicle film (referred to here as the "upper end surface") and a surface that faces the photomask when the photomask is attached (referred to here as the "lower end surface"). The upper end surface, the lower end surface, and the inner and outer surfaces of the pellicle frame do not need to be flat. If necessary, grooves, steps, and chamfering may be added. Typically, the pellicle film is attached to the upper end surface via an adhesive (adhesive layer), and an adhesive (adhesive layer) for attaching the pellicle to the photomask is attached to the lower end surface. 【0026】While there are no specific requirements for the material of the pellicle frame, metal is preferred due to the low risk of frame damage. There are no restrictions on the type of metal, and any known metal can be used. For pellicle frames used in EUV lithography, materials with a low coefficient of thermal expansion are preferred because they may be exposed to high temperatures. Examples include Invar, titanium, titanium alloys, and aluminum alloys, with titanium, titanium alloys, and aluminum alloys being preferred due to their ease of processing and lightweight properties. 【0027】 The dimensions of the pellicle frame are not particularly limited, but since the thickness (height) of the pellicle for EUV exposure is limited to less than 2.5 mm, the thickness of the pellicle frame for EUV exposure is smaller than that, less than 2.5 mm. Furthermore, considering the thickness of the pellicle film and mask adhesive, the thickness of the pellicle frame for EUV exposure is preferably 1.5 mm or less. 【0028】 Typically, the sides of the pellicle frame are provided with jig holes used for handling and peeling the pellicle from the photomask. These jig holes are usually not through-holes from the outer surface to the inner surface. The size of the jig holes is typically 0.5 to 1.0 mm in length in the thickness direction of the frame (or diameter in the case of a circular frame). For handling purposes, it is common to provide two jig holes on the outer surface of the longer side of the frame, but there are no restrictions on the number or shape of the holes; they can be circular or rectangular. Especially if there is a concern about damage to the pellicle film, it is preferable to provide jig holes for peeling in addition to the handling holes, and to peel the film at multiple points. 【0029】 Typically, pellicle frames have ventilation holes to prevent the membrane from bending when there are pressure changes inside and outside the pellicle. The size of these holes is 0.5 to 1.0 mm in length in the thickness direction of the frame (or diameter in the case of a circular frame). There are no restrictions on the shape of the holes; they can be circular or rectangular. The holes penetrate from the outer surface to the inner surface. There are no restrictions on the number or arrangement of the through-holes, but it is best to distribute them evenly along each side of the pellicle frame. Even distribution of the through-holes helps to mitigate airflow within the pellicle frame during pressure fluctuations. Filters may be provided at or inside the openings of the through-holes. The through-holes may also be used when peeling off the pellicle. 【0030】 Furthermore, while there are no restrictions on the material of the pellicle film, it is preferable to use a material with high transmittance at the wavelength of the exposure light source and high light resistance. For example, for EUV exposure, ultrathin silicon films or carbon films are used. 【0031】 The pellicle film does not need to be made of only one material. For example, one method for producing an ultrathin silicon film involves first forming a self-supporting pellicle film layer on a silicon wafer, and then etching the portion of the silicon wafer that will become the self-supporting film, thereby producing an ultrathin silicon self-supporting film supported by the frame of the silicon wafer. In such cases, the silicon wafer frame is also referred to as the pellicle film in this invention. 【0032】 In the EUV exposure pellicle of the present invention, a pellicle film is provided on the upper end surface of the pellicle frame via an adhesive or bonding agent. There are no restrictions on the material of the adhesive or bonding agent; known materials can be used, and acrylic adhesives and silicone adhesives are preferably used. The adhesive or bonding agent may be processed into any shape as needed. To strongly hold the pellicle film, an adhesive or bonding agent with strong adhesive strength is preferred. 【0033】 Furthermore, an adhesive layer is formed on the lower end surface of the pellicle frame for attaching the pellicle to the photomask. Known mask adhesives can be used to constitute the adhesive layer, with acrylic or silicone adhesives being preferred. The adhesive layer may be processed into any shape as needed. 【0034】 In the EUV exposure pellicle of the present invention, the adhesive layer of the EUV exposure pellicle is attached to a substrate made of a material that forms the outermost surface of the absorption film of the exposure master plate to which the pellicle is attached. By designing the force (peel strength) applied when peeling the EUV exposure pellicle from the substrate at a speed of 0.1 mm / s at a 90-degree angle to be in the range of 30 N to 70 N, the pellicle can be peeled off without putting stress on the pellicle film while holding the pellicle to the mask. The peel strength can be controlled by optimally selecting the adhesive strength of the adhesive and the application area of ​​the adhesive. 【0035】The substrate is made of a material that forms the outermost surface of the absorption film of the exposure master plate to which the pellicle is attached. Unlike the transmissive masks used for KrF and ArF, the exposure master plate is reflective. Generally, it is made of a substrate made of low thermal expansion glass, a multilayer film that reflects EUV light by forming a multilayer mirror in which Mo layers and Si layers are stacked alternately, a buffer film that protects the multilayer film, a cap film that protects the multilayer film in the mask manufacturing process, and an absorption film that absorbs EUV light by forming a circuit pattern with an EUV absorbent mainly composed of Ta, etc., all stacked in this order. The absorption film may have a composition that changes in steps in the thickness direction, or a composition that is continuously graded. Furthermore, there are also absorption films made of multilayer films with combinations of the above compositions. In this invention, since a configuration is adopted to evaluate the peel strength of the pellicle for EUV exposure in a manner close to the actual operation of pellicle replacement work, a substrate made of a material that forms the outermost surface of the absorption film of the exposure master plate to which the pellicle is attached is used in measuring the peel strength. Furthermore, when measuring the peel strength, the substrate made of the material forming the outermost surface of the absorption film of the exposure master plate may be, for example, one that has been formed on a master plate such as a quartz mask. 【0036】 The composition of the substrate varies, but as a material known to form the outermost surface of the absorption film of the exposure master plate (i.e., the surface to which the pellicle is attached), it can generally include at least one metal element selected from Ru, Ta, Cr, Rh, Mo, Nb, Ti, Zr, Y, Si, Pd, Ag, Pt, Au, Ir, W, Co, Mn, Sn, V, Ni, Fe, Hf, Cu, Te, Zn, Mg, Ge, Re, and Al. 【0037】 Furthermore, it is preferable that the substrate contains a compound of the metal element. In addition to the metal element, this compound may contain at least one nonmetal element selected from oxygen, nitrogen, carbon, and boron. 【0038】When fixing the pellicle frame of the EUV exposure pellicle of the present invention to the exposure plate with a mask adhesive, it is necessary to adjust the peel strength to 30N to 70N with respect to the outermost surface of the absorption film as described above. To achieve this, the mask adhesive used can be appropriately adjusted in adhesive strength or processed into any desired shape, and as a result, the peel strength to the substrate corresponding to the outermost surface of the absorption film of the desired photomask can be set to a range of 30N to 70N. 【0039】 The peel strength refers to the maximum strength achieved when, after attaching the pellicle to the substrate, a peeling jig is attached to two jig holes provided on the outer surface of one long side of the pellicle frame, and the jig is pulled up perpendicular to the substrate (90 degrees) at a speed of 0.1 mm / s until the pellicle is peeled off. When attaching the pellicle to the substrate, the pellicle is attached to the substrate with a load of 5 kg for 30 seconds, cured at room temperature for 12 hours, and then the peel strength is measured at room temperature. 【0040】 A pellicle with a peel strength of 30N to 70N from the substrate is preferable because it is easy to replace and there is no concern about the pellicle falling off during use. More preferably, 35N to 65N is particularly preferable. If the peel strength is less than 30N, there is a concern that the pellicle may shift or fall off during exposure. On the other hand, if the peel strength is greater than 70N, the adhesive force is too strong, causing the frame to bend during peeling, applying force to the pellicle film, and raising concerns that the pellicle film may be damaged. If the pellicle film is damaged, the mask will be contaminated, and it will take a very long time to regenerate the mask. 【0041】 The apparatus used when implementing a method for measuring the peel strength when peeling a pellicle from a substrate is not particularly limited, but for example, the following apparatus can be used. Figure 2 is a schematic perspective view of a pellicle peeling apparatus according to one embodiment, and Figure 3 is a schematic view of a uniaxial robot of a pellicle peeling apparatus according to one embodiment. The pellicle peeling apparatus 20 is an example of an apparatus used when performing pellicle peeling. 【0042】The pellicle peeling device 20 includes four pellicle frame support pins 21, four pin support shafts 22, four single-axis robots 24, and four load cells 23. 【0043】 The four pellicle frame support pins 21 are provided in two on each outer side surface of the long side of the pellicle frame 11 at a required interval, and a total of four are provided on both sides. The pellicle frame support pins 21 are respectively fitted and coupled into four jig holes 30 provided at both end faces of the pellicle frame 11, and are provided to lift the pellicle 10 from the exposure original plate 1 and peel it off with the pellicle frame 11. The insertion end portion of the cylindrical pellicle frame support pin 21 is conical, and the jig hole 30 is a circular hole whose frontage portion matches the cylindrical shape of the pellicle frame support pin 21, and the inner portion is a conical hole that matches the conical shape of the pellicle frame support pin 21. Therefore, the pellicle frame support pin 21 fits into the jig hole 30 without rattling. 【0044】 The four pin support shafts 22 integrally support the base end portions of the corresponding pellicle frame support pins 21 at the lower end portions and are provided so as to be able to move up and down in the vertical direction. 【0045】 As shown in FIG. 3, each of the four single-axis robots 24 has, for example, a servo motor 25 (including a motor driver), a pinion 26 rotated by the servo motor 25, and a lifting shaft 28 having a rack 27 that meshes with the pinion 26 and moves in the axial direction in response to the rotation of the pinion 26, inside a casing. The lower end portion of the lifting shaft 28 is connected to the upper end of the pin support shaft 22. Instead of the combination of the servo motor 25, the pinion 26, and the rack 27, a linear actuator can also be used, and a piezoelectric actuator can be selected. 【0046】The four load cells 23 are provided, for example, so as to be sandwiched under one of two bearings that support both ends of the pinion shaft of the uniaxial robot 24. The other bearing and the load cell 23 are lifted by a spring 29. When the servo motor 25 of the power source operates and the pellicle frame support pin 21 lifts the pellicle frame 11, the force applied to the pellicle frame support pin 21 is sequentially transmitted to the pin support shaft 22, the rack 27, the pinion 26, and the load cell 23. Therefore, when lifting the pellicle frame 11, the force applied to the pellicle frame support pin 21, that is, the peeling force, can be measured. 【0047】 A computer (not shown) that controls each servo motor 25 inputs the measurement value output by the load cell 23, performs A / D conversion, generates a motor drive signal of a predetermined multiple according to the magnitude of the conversion value, and outputs this motor drive signal to the motor driver of the corresponding servo motor 25. 【0048】 Thereby, the servo motor 25 can move the pellicle frame support pin 21 in the direction in which the pellicle 10 peels from the reticle 1 so that the output of the load cell 23 that measures the force applied to the corresponding pellicle frame support pin 21 is minimized. 【0049】 Subsequently, a method for peeling a pellicle according to one embodiment will be described. The peeling method is performed using the above-described pellicle peeling device. 【0050】 The method for peeling the pellicle includes a pellicle frame 11, a pellicle film 12 stretched via a pellicle film adhesive 13 on one end surface (the upper surface portion in FIG. 1) of the pellicle frame 11, and an adhesive layer 14 provided on the other end surface (the lower surface portion in FIG. 1) of the pellicle frame 11. It is a method for peeling the EUV exposure pellicle 10 in which the adhesive layer 14 is adhered to the reticle 1 from the reticle 1. 【0051】The pellicle peeling method involves inserting one pellicle frame support pin 21 for peeling the pellicle 10 into each of the four jig holes 30 provided on both outer surfaces on both sides of the long side of the pellicle frame 11, measuring the peeling force applied to the pellicle frame support pin 21, and controlling the movement speed and direction of the pellicle frame support pin 21 so as to minimize the peeling force, while moving the pellicle frame support pin 21 in a direction in which the adhesive layer 14 of the pellicle 10 separates perpendicularly from the exposure master plate 1 (pellicle peeling direction) to peel off the pellicle 10. 【0052】 The pellicle peeling method is carried out by independently measuring and controlling the peeling strength applied to each of the four pellicle frame support pins 21, which are inserted into four jig holes 30 provided on both outer surfaces on both sides of the long side of the pellicle frame 11. 【0053】 Implementing the peel strength independently is effective in mitigating the effects of the peeling process, as when the pellicle 10 is simultaneously lifted by the four pellicle frame support pins 21 shown in Figure 2, the adhesive layer 14 separates from the exposure master plate 1 across the entire surface of the adhesive layer 14, which can cause distortion of the exposure master plate 1 and peeling residue of the adhesive layer. 【0054】 Although not shown in Figure 2, the pellicle peeling device 20 is equipped with a stage. The exposure master plate 1 with the pellicle 10 attached is set on this stage with the pellicle 10 facing upwards. When repelling is required to replace the pellicle with a new one, the pellicle frame support pins 21 are inserted into the four jig holes 30 provided on both sides of the pellicle frame 11, and the start button (not shown) is pressed to start the operation of the pellicle peeling device. Four uniaxial robots 24, in relation to the measured values ​​of the corresponding load cells 23, each pull up the pellicle frame support pins, pulling up the pellicle 10 and peeling the adhesive layer 14 of the pellicle 10 from the exposure master plate 1. In this way, the peeling strength of the pellicle can be measured. 【0055】The mask adhesive (adhesive layer) is preferably applied around the entire circumference of the pellicle frame. It is not necessary to apply the mask adhesive to the entire lower end surface of the pellicle frame; if necessary, the width of the adhesive application may be narrower than the frame width to achieve suitable peel strength. 【0056】 A release layer (separator) may be attached to the lower end surface of the mask adhesive to protect the adhesive. The material of the release layer is not particularly limited, but for example, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), polyethylene (PE), polycarbonate (PC), polyvinyl chloride (PVC), polypropylene (PP), etc. may be used. In addition, if necessary, a release agent such as a silicone-based release agent or a fluorine-based release agent may be applied to the surface of the release layer. 【0057】(Example 1) A pellicle frame (external dimensions 150 mm x 118 mm x 1.5 mm, frame width 4.0 mm) was made of titanium. The corners were given a rounded corner shape, with the inner corner being R1 and the outer corner being R5. Two handling jig holes, 1 mm in diameter and 1.2 mm in depth, were made on the outer surface of the long side of the pellicle frame, spaced 104 mm apart from the center of the side. Furthermore, five peeling jig holes, 0.8 mm in diameter and 3 mm in depth, were made at 32.5 mm intervals around the center. Four peeling jig holes, 0.8 mm in diameter and 3 mm in depth, were made on the outer surface of the short side of the pellicle frame, spaced 32.5 mm apart around the center. The pellicle frame was cleaned, and a mixture of 100 parts by mass of silicone adhesive (Shin-Etsu Chemical Co., Ltd., X-40-3264), 1 part by mass of hardener (Shin-Etsu Chemical Co., Ltd., PT-56), was added and mixed. This mixture was applied to the entire circumference of the upper end surface of the frame to a thickness of 0.1 mm. On the lower end surface of the frame, a mixture of 100 parts by mass of acrylic adhesive (Soken Chemical Co., Ltd., SK-Dyne 1170), 1 part by mass of hardener (Soken Chemical Co., Ltd., E-14), was added and mixed. This mixture was applied along the outer diameter of the frame in a 1 mm width and to a thickness of 0.1 mm. The pellicle frame was then heated at 90°C for 12 hours to cure the adhesives on the upper and lower end surfaces. Subsequently, an ultra-thin silicone film was pressed onto the adhesive formed on the upper end surface of the frame to complete the pellicle. 【0058】 (Example 2) As a mask adhesive, 100 parts by mass of acrylic adhesive (SK Dyne 1495, manufactured by Soken Chemical Co., Ltd.) was mixed with 0.1 parts by mass of a hardening agent (L-45K, manufactured by Soken Chemical Co., Ltd.) and stirred. This mixture was then applied to the entire circumference of the frame along its outer diameter, in a width of 2 mm, to a thickness of 0.1 mm. The pellicle was completed in the same manner as in Example 1. 【0059】(Example 3) As a mask adhesive, 100 parts by mass of silicone adhesive (Shin-Etsu Chemical Co., Ltd., X-40-3264) was mixed with 1 part by mass of curing agent (Shin-Etsu Chemical Co., Ltd., PT-56) and the mixture was applied to the entire circumference of the frame along the outer diameter to a width of 1 mm and a thickness of 0.1 mm. The pellicle was completed in the same manner as in Example 1. 【0060】 (Comparative Example 1) As a mask adhesive, 100 parts by mass of acrylic adhesive (SK Dyne 1495, manufactured by Soken Chemical Co., Ltd.) was mixed with 0.1 parts by mass of a hardening agent (L-45K, manufactured by Soken Chemical Co., Ltd.) and stirred. This mixture was then applied to the entire circumference of the frame along its outer diameter to a width of 1 mm and a thickness of 0.1 mm. The pellicle was completed in the same manner as in Example 1. 【0061】 (Comparative Example 2) As a mask adhesive, 100 parts by mass of acrylic adhesive (SK Dyne 1425, manufactured by Soken Chemical Co., Ltd.) was mixed with 0.25 parts by mass of a hardening agent (L-45K, manufactured by Soken Chemical Co., Ltd.), and the mixture was applied to the entire circumference of the frame along the outer diameter to a width of 1 mm and a thickness of 0.1 mm. The pellicle was completed in the same manner as in Example 1. 【0062】 For the pellicles of Examples 1-3 and Comparative Examples 1-2, peel strength measurements, peel tests to confirm the presence or absence of pellicle film damage, and load tests to evaluate the pellicle's holding power were performed as described below. 【0063】[Measurement of Peel Strength] A 100 nm thick Ta film was deposited on the surface of a 6-inch square quartz mask to prepare a Ta substrate. Before use, it was thoroughly washed with pure water, and the surface was irradiated with UV light for 1 minute to remove surface contaminants. The pellicles prepared in Examples 1-3 and Comparative Examples 1-2 were attached to the Ta substrate with a load of 5 kg for 30 seconds and left at room temperature for 12 hours. The four corners of the Ta substrate were fixed, and peel pins were inserted from the outside of the frame into two handling jig holes provided on the long side of one pellicle frame. Then, at room temperature, the peel pins were pulled up at 0.1 mm / second perpendicular to the Ta substrate (in the direction of the pellicle film) to peel off the pellicle. A load cell was provided on the peel pin side, and the force required for peeling was measured at 0.2-second intervals. The maximum strength from when the pellicle was pulled up until it was completely peeled off was measured as the peel strength (N). 【0064】 [Peel Test] A 100 nm thick Ta film was deposited on the surface of a 6-inch square quartz mask to prepare a Ta substrate. Before use, it was thoroughly washed with pure water, and the surface was irradiated with UV light for 1 minute to remove surface contaminants. The pellicles prepared in Examples 1-3 and Comparative Examples 1-2 were attached to the Ta substrate with a load of 5 kg for 30 seconds and left at room temperature for 12 hours. The four corners of the Ta substrate were fixed, peel pins were inserted into the holes of the peeling jig, and at room temperature, the peel pins were simultaneously pulled up at 0.1 mm / second perpendicular to the substrate (in the direction of the pellicle film) to check for any damage to the pellicle film after peeling. 【0065】 [Load Test] A 100 nm thick layer of Ta was deposited on the surface of a 6-inch square quartz mask to prepare a Ta substrate. Before use, it was thoroughly washed with pure water, and the surface was irradiated with UV light for 1 minute to remove surface contaminants. The pellicles prepared in Examples 1-3 and Comparative Examples 1-2 were attached to the Ta substrate with a load of 5 kg for 30 seconds and left at room temperature for 12 hours. The four corners of the Ta substrate were fixed, and the Ta substrate was positioned horizontally so that the pellicle faced downwards. A 1 kg load was applied to the pellicle and left at 60°C for 24 hours to check whether the pellicle fell off or not. 【0066】Table 1 shows the results of various tests performed on the pellicles of Examples 1-3 and Comparative Examples 1-2. 【0067】 【0068】 From the above results, it was confirmed that by using a pellicle with a peel strength of 30N to 70N when peeled from a Ta substrate at a speed of 0.1 mm / s at a 90-degree angle, the risk of pellicle film damage during peeling can be suppressed, while maintaining the pellicle's holding power. From these results, it was found that the EUV exposure pellicle of the present invention is extremely useful as an EUV exposure pellicle that requires frequent replacement. Furthermore, since the EUV exposure pellicle of the present invention is configured to fix the pellicle to the mask with a mask adhesive, similar to conventional KrF and ArF pellicles, it is possible to regenerate the mask using the same equipment and methods as before. 【0069】 1. Exposure master plate 10. Pellicle for EUV exposure 11. Pellicle frame 12. Pellicle film 13. Adhesive for pellicle film 14. Adhesive layer 15. Ventilation through-holes 16. Filter 20. Pellicle peeling device 21. Pellicle frame support pins 22. Pin support shafts 23. Load cell 24. Uniaxial robot 25. Servo motor 26. Pinion 27. Rack 30. Jig holes

Claims

1. An EUV exposure pellicle used in EUV lithography, characterized in that the peel strength of the EUV exposure pellicle, which has an adhesive layer attached to a substrate made of a material forming the outermost surface of the absorption film of an exposure plate to which the EUV exposure pellicle is attached, is 30N to 70N when the EUV exposure pellicle is peeled from the substrate at a speed of 0.1 mm / s at a 90-degree angle.

2. The pellicle for EUV lithography according to claim 1, wherein the substrate contains at least one metallic element selected from Ru, Ta, Cr, Rh, Mo, Nb, Ti, Zr, Y, Si, Pd, Ag, Pt, Au, Ir, W, Co, Mn, Sn, V, Ni, Fe, Hf, Cu, Te, Zn, Mg, Ge, Re, and Al.

3. The pellicle for EUV exposure according to claim 2, wherein the substrate comprises at least one nonmetallic element selected from oxygen, nitrogen, carbon, and boron.

4. An exposure master plate with a pellicle, characterized in that the pellicle for EUV exposure described in claim 1 is installed on the exposure master plate.

5. An exposure method characterized by exposure using the EUV exposure pellicle described in claim 1.

6. A method for manufacturing a semiconductor, characterized by comprising the step of exposure using the EUV exposure pellicle described in claim 1.

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