Pellicle

Abstract

Provided is a pellicle in which the membrane stress in the pellicle film is adjusted to be suitable, distortion due to turbulent flow, etc., is kept under control, and the structural stability is excellent.　A pellicle (1) is provided with a rectangular frame (2), a pellicle film (3) provided to one surface of the frame (2), and a mask adhesive (4) provided to the other surface of the frame (2). The length of the longer side of the frame (2) is 600 mm or greater and the length of the shorter side is 500 mm or greater. The pellicle is characterized in that when a predetermined air-blast flutter experiment is carried out, the sum of displacement (T1) in a first direction and displacement (T2) in a second direction (Δ displacement = T1 + T2) is between 1.50 mm and 2.80 mm, and the greater of a maximum displacement (T1max) in the first direction and a maximum displacement (T2max) in the second direction (flutter amounts) is between 1.00 mm and 2.40 mm.

Description

[Technical Field]

[0001] The present invention relates to a pellicle. [Background technology]

[0002] In the world of photolithography, in addition to exposure to small areas such as semiconductor IC chips, one-shot exposure technology for larger areas such as flat panel displays such as liquid crystal displays has been developed. In the manufacturing process of semiconductor devices such as large-scale integrated circuits (LSIs) and ultra-LSIs, and liquid crystal display panels, patterning is performed by irradiating a photosensitive layer or the like with light through a mask (also called an exposure master or reticle). If foreign matter adheres to the mask, the light is absorbed by the foreign matter or is reflected and bent by the surface of the foreign matter. As a result, the formed pattern may be deformed or have rough edges, resulting in problems such as impaired dimensions, quality, and appearance after patterning. To solve these problems, a method has been adopted in which a pellicle with a light-transmitting pellicle film is attached to the surface of the mask to suppress the adhesion of foreign matter (e.g., Patent Document 1).

[0003] When such a pellicle is mounted on a mask, the inside of the pellicle is extremely airtight, and changes in air pressure or temperature can cause the thin pellicle film to sag or bulge. If the pellicle film loses its smoothness in this way, not only will its optical properties change, but if the pellicle film is severely uneven, it may come into contact with the mask or equipment, causing damage to the pellicle film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-160466 Summary of the Invention [Problem to be solved by the invention]

[0005] In particular, in large pellicles such as those used in the manufacture of flat panel displays, it is difficult for the membrane tension to reach the center of the pellicle membrane. If the membrane tension is too low, the membrane center is likely to bend, and if the membrane tension is too high, the stress on the frame increases, making it difficult to ensure structural stability.

[0006] The present invention has been proposed in consideration of the above-described conventional situation, and an object of the present invention is to provide a pellicle in which the membrane tension of the pellicle membrane is suitably adjusted, deformation due to wind pressure, etc. is suppressed, and the pellicle has excellent structural stability. [Means for solving the problem]

[0007] The present invention is as follows. [1] A pellicle comprising a rectangular frame, a pellicle film provided on one side of the frame, and a mask adhesive provided on the other side of the frame, wherein the length of the long side of the frame is 600 mm or more and the length of the short side is 500 mm or more, Steps below: (1) attaching the pellicle to a flat plate via the mask adhesive; (2) providing a gap of 5.5 mm, 8.0 mm, 10.0 mm, or 12.0 mm between the pellicle and another flat plate; (3) a step of measuring the amount of displacement of the pellicle film in the thickness direction relative to a virtual plane including one surface of the frame body when stationary, over a predetermined measurement time when air is blown between the pellicle and the other flat plate at 1,000 mm / sec along the long side direction of the pellicle using a blower; and (4) obtaining a displacement amount in a first direction toward the flat plate and a displacement amount in a second direction away from the flat plate from the displacement amounts; When conducting a ventilation experiment with The sum of the displacement amount (T1) in the first direction and the displacement amount (T2) in the second direction (Δdisplacement amount=T1+T2) is 1.50 mm to 2.80 mm, and The maximum displacement in the first direction (T1 max ) and the maximum displacement in the second direction (T2 ma x ) the larger of these (amount of flapping) is 1.00 mm to 2.40 mm. [2] The maximum displacement in the first direction (T1 max ) is the maximum displacement in the second direction (T2 m ax ) The pellicle according to [1], [3] The pellicle described in [1] or [2], wherein the Δ displacement amount and the flapping amount are obtained based on measurement results at multiple measurement points along the pellicle membrane in the air flapping experiment. [4] A pellicle described in any of [1] to [3], wherein in the air blowing experiment, there are provided two or more combinations of measurement points where the maximum displacement in the first direction at the measurement point upstream of the air blowing is greater than the maximum displacement in the first direction at the measurement point downstream of the air blowing. [5] A pellicle described in any of [1] to [4], wherein in the air blowing experiment, there are provided two or more combinations of measurement points where the maximum displacement in the second direction at the measurement point upstream of the air blowing is smaller than the maximum displacement in the second direction at the measurement point downstream of the air blowing. [6] The pellicle according to any one of [1] to [5], wherein the length of the long side of the frame is 600 mm or more and 4000 mm or less, and the length of the short side is 500 mm or more and 3000 mm or less. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a pellicle in which the membrane tension of the pellicle membrane is suitably adjusted, deformation due to wind pressure and the like is suppressed, and the pellicle has excellent structural stability. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of a configuration of a pellicle. [Figure 2] FIG. 1 is a diagram showing a schematic configuration example of an experimental device used in a blowing air experiment. [Figure 3] 1 is a graph schematically showing the displacement of the pellicle film measured by each of the laser displacement meters P1 to P6. [Figure 4] 10 is a graph showing the displacement of the pellicle film measured by laser displacement meters P1 to P6 at the first measurement points in an example. [Figure 5] 10 is a graph showing the displacement of the pellicle film measured by laser displacement meters P1 to P6 at the second measurement points in the example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a description will be given of an embodiment of the present invention (hereinafter abbreviated as "embodiment") with reference to the drawings. The present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist of the present invention. In each drawing, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted.

[0011] An overview of the pellicle according to this embodiment will be described below. Fig. 1(a) is a top view showing a pellicle 1, and Fig. 1(b) is a longitudinal cross-sectional view. In the following description, the upper side of each figure will be referred to as "top" and the lower side as "bottom." Similarly, the right side of each figure will be referred to as "right" and the left side as "left." Furthermore, in this specification, numerical ranges indicated using "to" include the upper and lower limit values.

[0012] <Pellicle> Pellicle 1 is a structure that protects photomasks from dust in photolithography, etc. Pellicle 1 includes a rectangular frame 2, a pellicle film 3 provided on one side of frame 2, an adhesive layer 4 provided on the other side of frame 2, and a release film 5.

[0013] The frame 2 (pellicle frame) can have any shape that allows the pellicle membrane 3 to be stretched over the frame 2, and for example, can have an outer shape such as a rectangle when viewed from the front. The rectangle can be a square, oblong, or the like, and can have both right-angled corners and a roughly rectangular shape with rounded corners (FIG. 1).

[0014] The sizes of the frame 2 and its opening can be determined according to the size of the photomask. When the frame 2 has a rectangular shape consisting of a pair of long sides and a pair of short sides in a front view, the long side length can be 600 mm to 4000 mm, 600 mm to 3000 mm, or 600 mm to 2000 mm, the short side length can be 500 mm to 3000 mm, 500 mm to 2000 mm, or 500 mm to 1800 mm, the widths of the long and short sides can each be 4.0 mm to 20.0 mm, and / or the frame height can be 2.0 mm to 10.0 mm. In particular, the pellicle 1 of this embodiment is preferably a large pellicle in which the length of the long side of the frame body 2 is 600 mm or more and the length of the short side is 500 mm or more, and it is more preferable that the length of the long side of the frame body 2 is 1700 mm or more and the length of the short side is 1600 mm or more.

[0015] As shown in FIG. 1, the frame 2 has edges. The edges can have rod-shaped edge members that extend linearly. A pair of edge members can be arranged parallel to each other with a gap between them, and similarly, another pair of edge members can be arranged parallel to each other with a gap between them. The ends of two contacting edge members can be connected so that they form approximately a right angle with each other.

[0016] The frame 2 and its edge members can be formed from known materials such as aluminum; aluminum alloys (e.g., 5000 series, 6000 series, 7000 series, etc.); titanium; titanium alloys; steel; stainless steel; magnesium alloys; ceramics (e.g., SiC, AlN, Al2O3, etc.); composite materials of ceramics and metals (e.g., Al-SiC, Al-AlN, Al-Al2O3, etc.); engineering plastics such as PE, PA, PC, PEEK, etc.; fiber composite materials such as GFRP, CFRP, etc.; or combinations thereof.

[0017] The lower limit of the thickness of the frame 2 is preferably 3.0 mm or more, more preferably 3.5 mm or more, and even more preferably 4.0 mm or more. On the other hand, the upper limit of the thickness of the frame 2 is preferably 10.0 mm or less, more preferably 8.0 mm or less, and even more preferably 7.0 mm or less.

[0018] The width of the frame 2 is preferably between 3.5 mm and 30 mm. This range is preferable because it can withstand the tension of the pellicle film 3 while ensuring an effective exposure area. The lower limit of the width of the frame 2 is more preferably 4.0 mm or more, even more preferably 6.0 mm or more, and even more preferably 12.0 mm or more, and it is preferable to change the width of the frame 2 so that it can withstand the film tension depending on the area of ​​the frame 2. In particular, in the case of a frame 2 whose long side length is 1700 mm or more and whose short side length is 1600 mm or more, the width of the frame 2 is preferably 15.0 mm or more. On the other hand, the upper limit of the width of the frame 2 is more preferably 25 mm or less, even more preferably 20 mm or less. The width of the frame 2 may be the same for both the long and short sides, or may be independent of each other.

[0019] If necessary, an adhesive (e.g., acrylic, vinyl acetate, silicone, rubber-based adhesive, etc.) or grease (e.g., silicone-based, fluorine-based grease, etc.) may be applied to the inner surface or entire surface of the frame body 2 to capture foreign matter.

[0020] The pellicle film 3 is a transparent thin film. The pellicle film 3 has a thickness of 10 μm or less and is formed so as to sufficiently transmit light emitted from a light source in photolithography. In particular, the thickness is preferably 2.0 μm to 4.5 μm.

[0021] The material constituting the pellicle membrane 3 is not particularly limited, but examples thereof include nitrocellulose, cellulose derivatives, fluoropolymers, and carbon materials, and among these, carbon materials are preferred.

[0022] As shown in FIG. 1( b ), the pellicle film 3 is adhered and fixed to one end of the frame body 2 with an adhesive (not shown), and covers the frame body 2 .

[0023] As shown in FIG. 1(b), an adhesive layer 4 for attaching the pellicle 1 to the photomask is disposed on the other end side of the frame 2 (the side of the frame 2 opposite to the pellicle film 3).

[0024] The adhesive layer 4 (mask adhesive layer) is composed of an adhesive such as an acrylic, rubber, vinyl, epoxy, or silicone adhesive, and more preferably an acrylic, rubber, or silicone adhesive, etc. The thickness of the adhesive layer 4 is preferably, for example, 0.8 mm to 3.0 mm.

[0025] A release film 5 (liner) is disposed so as to cover the adhesive layer 4. This release film 5 protects the adhesive layer 4 when not in use, and is peeled off from the adhesive layer 4 when the pellicle 1 is in use. A film of polyester or the like having a thickness of about 30 μm to 200 μm is generally used for the release film 5. If the peeling force required to peel the release film 5 from the adhesive layer 4 is too great, the adhesive layer 4 may be deformed during peeling. Therefore, the surface of the film that comes into contact with the adhesive may be subjected to a release treatment such as silicone or fluorine to ensure an appropriate peeling force.

[0026] The release film 5 has a width greater than that of the adhesive layer 4 and is disposed so as to extend beyond the adhesive layer 4 onto the outer periphery of the frame 2 .

[0027] In the pellicle 1 according to this embodiment, the tension of the pellicle film 3 is adjusted appropriately so that the amount of displacement and flapping amount when the air blow flapping experiment described below is carried out falls within a predetermined range. As a result, in the pellicle 1 of this embodiment, an appropriate film tension extends to the central portion of the pellicle film 3, preventing deflection in the central portion of the pellicle film 3, and the stress applied to the frame body 2 is also appropriate, preventing distortion, ensuring structural stability even in large pellicles.

[0028] <Air blowing experiment> The air blowing experiment defined in the present invention will be described below. The air blowing experiment includes the following steps. (1) Step of attaching the pellicle 1 to a flat plate 12 (plane plate) via an adhesive layer 4; (2) providing a gap of 5.5 mm, 8.0 mm, 10.0 mm, or 12.0 mm between the pellicle 1 and the surface plate 11 (another flat plate); (3) a step of measuring the amount of displacement of the pellicle film 3 in the thickness direction relative to a virtual plane including one surface of the frame 2 when stationary, over a predetermined measurement time when air is blown at 1,000 mm / sec along the long side direction of the pellicle 1 using the blower 13; and (4) The maximum displacement in the first direction (T1 m ax ) and the maximum displacement in the second direction away from the plate (T2 max ) and a step of obtaining; Each step will be explained below.

[0029] (1) The pellicle 1 is attached to a flat plate via the adhesive layer 4 (mask adhesive layer). FIG. 2 is a diagram showing a schematic configuration example of an experimental device for measuring the amount of flapping of the pellicle film 3 (air-blowing flapping experiment) in the present invention, where (a) is a top view and (b) is a side view.

[0030] The experimental device 10 for the air blowing experiment comprises a stone surface plate 11, a flat plate 12 (flat plate) arranged above the stone surface plate 11 at a predetermined distance and generally parallel to the stone surface plate 11, a plurality of laser displacement meters P1 to P6 arranged on the side of the flat plate 12 opposite the side facing the stone surface plate 11 (another flat plate), and a blower 13 that blows air toward the space between the stone surface plate 11 and the flat plate 12. From the viewpoint of air blowing stability, the stone surface plate 11 preferably has a predetermined flatness, and from the viewpoint of structural stability, it is preferable that the stone surface plate 11 has a predetermined rigidity.

[0031] The flat plate 12 is preferably made of a transparent and easily processable material, particularly an acrylic plate, because the flat plate must be cut to the shape of the laser displacement meters P1 to P6 so that the displacement of the pellicle film 3 can be measured by the laser displacement meters P1 to P6 and the state of the pellicle film can be visualized. During the air blowing experiment, the pellicle 1 is attached to the lower surface of the flat plate 12 by the adhesive layer 4.

[0032] The sizes of the stone surface plate 11 and the flat plate 12 are not particularly limited, but are determined by the size of the pellicle 1 to be measured, and are usually larger than the pellicle 1. In this embodiment, the size of the pellicle 1 is 1780 mm long side × 1620 mm short side, and the size of the flat plate 12 is 2000 mm × 2000 mm. In addition, it is preferable that the size of the stone surface plate 11 is larger than that of the flat plate 12.

[0033] When the pellicle 1 becomes large, for example, with a long side of 1700 mm or more, the problem of the pellicle film 2 flapping becomes significant. That is, as the pellicle film 1 becomes larger, the deflection and flapping of the pellicle film 3 itself also becomes larger, but also in the exposure apparatus, as the spacing between components becomes narrower and the movement of the mask stage becomes faster and more complex, the effects of the deflection and flapping of the pellicle film 3 become greater, increasing the possibility that the pellicle film 3 will come into contact with the mask or components and be damaged. If the pellicle film is damaged, it will have adverse effects such as causing the focus to shift during exposure.

[0034] Therefore, the air blowing experiment of the present invention is aimed at a large pellicle having a frame 2 with a long side of at least 1700 mm or more. The present invention optimizes the tension of the pellicle film 3 to reduce the effect of flapping, taking into account the effect of wind pressure caused by high-speed movement of the mask stage, in large pellicles with a long side of the frame body 2 of at least 1700 mm or more; the effect of the present invention cannot be obtained by simply increasing the size of a conventional pellicle.

[0035] A blower 13 is disposed on the outside of the flat plate 12 and the stone surface plate 11. The blower 13 is a device that blows air into the space between the pellicle 1 attached to the flat plate 12 and the stone surface plate 11. In the example shown in FIG. 2, the blower 13 blows air W from the left side to the right side in the figure at a predetermined air velocity.

[0036] Laser displacement meters P1 to P6 are devices that measure the displacement (displacement direction and displacement amount) of pellicle film 3 when air is blown, and are arranged on the side of flat plate 12 opposite to the side on which pellicle 1 is attached. It is preferable to provide a plurality of measurement points using the laser displacement meters P1 to P6. In this embodiment, six laser displacement meters P1 to P6 are arranged at 300 mm intervals in the central part of the pellicle film 3 along the air blowing direction.

[0037] In such an experimental device, the release film 5 of the pellicle 1, which is the object to be measured, is peeled off, and the exposed adhesive layer 4 is attached to face the lower surface of the flat plate 12.

[0038] (2) A gap of 5.5 mm, 8.0 mm, 10.0 mm, or 12.0 mm is provided between the pellicle 1 and the granite surface plate 11 (another flat plate). The distance D between the pellicle 1 attached to the flat plate 12 and the stone surface plate 11 can be set appropriately to match the distance between the pellicle 1 and the device components in the lithography device in which the pellicle 1 is actually used. In this embodiment, the distance D is set to 5.5 mm to 12.0 mm.

[0039] (3) Air is blown along the pellicle 1 using the blower 13, and the amount of displacement of the pellicle film 3 in the thickness direction is measured. Air is blown into the space between the pellicle film 3 and the stone surface plate 11 using the blower 13, and the amount of displacement of the pellicle film 3 due to the wind pressure is measured.

[0040] In this embodiment, the air velocity of the air blower 13 is set to 1000 mm / sec at the center of the pellicle film 3. One set of air blowing consists of a 2-second air blow followed by a 2-second interval, and this is repeated four times. Six laser displacement meters P1 to P6 are arranged along the airflow direction to measure the displacement (direction and amount of displacement) of the pellicle film 3 at each point.

[0041] Specifically, a virtual plane including one surface of the frame 2 when stationary is used as a reference for the displacement of the pellicle film 3. This virtual plane represents the pellicle film 3 when stationary.

[0042] Then, over a predetermined measurement time (air blowing time), the amount of displacement (T1) in a first direction toward the flat plate 12 and the amount of displacement (T2) in a second direction away from the flat plate 12 are obtained relative to the imaginary plane. In Fig. 2(b), the first direction is the direction toward the upper side from the imaginary plane, and the second direction is the direction toward the lower side from the imaginary plane.

[0043] (4) The maximum displacement in the first direction toward the plane (T1 max ) and the maximum displacement in the second direction away from the plane (T2 max ) and obtain. The maximum displacement (T1) among the displacements (T1) in the first direction obtained in the step (2) max ), and the maximum displacement (T2) in the second direction max ), respectively.

[0044] In the pellicle 1 of this embodiment, (a) The sum of the displacement in the first direction (T1) and the displacement in the second direction (T2) (Δ displacement = T1 + T2) is 1.50 mm to 2.80 mm, and (b) Maximum displacement in the first direction (T1 max ) and the maximum displacement in the second direction (T2 max The larger of these (amount of flapping) is 1.00mm to 2.40mm.

[0045] This prevents deformation (displacement or flapping) of the pellicle film 3 even if wind pressure is applied to the pellicle film 3 due to movement of the mask stage, thereby reducing the risk of the pellicle film 3 coming into contact with the mask or equipment parts.

[0046] The amount of displacement and flapping of the pellicle film 3 can be adjusted to fall within the above range by appropriately adjusting the film tension of the pellicle film 3. Specifically, for example, one method includes appropriately adjusting the direction and magnitude of the tension applied to the pellicle film 3 when attaching the pellicle film 3 to the frame 2.

[0047] Specifically, for example, a frame 2 having a pair of sides bulging outward is used, and when attaching the pellicle film 3 to the frame 2, the bulging sides are elastically deformed toward the inside of the frame 2, and the pellicle film 3 is then attached and stretched, thereby easily balancing the restoring force of the frame 2 and the stretching force of the pellicle film 3. At this time, by adjusting the amount of bulging of the sides within a predetermined range, the direction and magnitude of the tension applied to the pellicle film 3 can be appropriately adjusted. Furthermore, by constructing the frame 2 from a material having a Young's modulus within a predetermined range, when the pellicle film 3 is attached to the frame 2, the restoring force of the frame 2 and the film tension of the pellicle film 3 can be appropriately balanced in a state in which the frame 2 assumes a substantially rectangular shape. In this case, a material with a Young's modulus of 100 MPa or more is preferred.

[0048] Alternatively, when attaching the pellicle film 3 to the frame 2, the humidity may be set to be equal to or higher than the humidity inside the exposure device. This makes it possible to maintain the stress at a low level, and the tension applied to the pellicle membrane 3 can be adjusted appropriately.

[0049] If (a) the sum of the displacement amounts T1 and T2, or (b) the amount of flapping is larger than the above range, the tension applied to the pellicle film 3 is low, and deflection may occur in the central portion of the pellicle film 3. Also, if (a) the sum of the displacement amounts T1 and T2, or (b) the amount of flapping is smaller than the above range, excessive tension is applied to the pellicle film 3, and the stress applied to the frame 2 is large, and distortion may occur.

[0050] From the viewpoint of suppressing deformation of the pellicle film 3 and balancing the tension of the pellicle film 3 and the stress of the frame 2, it is necessary to satisfy both (a) and (b). As a result, in the pellicle 1 of this embodiment, an appropriate membrane tension extends to the central portion of the pellicle membrane 3, suppressing the occurrence of deflection in the central portion of the pellicle membrane 3, and the stress applied to the frame body 2 is also appropriate, suppressing the occurrence of distortion and resulting in excellent structural stability.

[0051] (a) Δ displacement (= T1 + T2) is preferably more than 1.50 mm and less than 2.80 mm, and more preferably 1.60 mm to 2.70 mm, and (b) flapping amount is preferably more than 1.00 mm and less than 2.40 mm, and more preferably 1.10 mm to 2.35 mm. This allows the structural stability of the pellicle 1 to be improved.

[0052] It is preferable that the Δ displacement amount and the flapping amount are obtained based on the measurement results at a plurality of measurement points along the pellicle film 3 in an air blow flapping experiment. Naturally, the behavior in the airflow flapping experiment differs between the edge and center, and the upstream and downstream sides of the airflow, of the pellicle film 3. By setting up multiple measurement points instead of just one, and knowing the trends at each point across the entire pellicle 1 in more detail, the reliability of the airflow flapping experiment can be improved, and the amount of displacement and flapping of the pellicle as a whole can be kept small.

[0053] Furthermore, in the wind flapping experiment, the maximum displacement in the first direction (T1 max ) is the maximum displacement in the first direction at the measurement point downstream of the airflow (T1 max ) It is preferable to provide two or more combinations of measurement points larger than the above. This makes it possible to improve the reliability of the air blowing experiment.

[0054] In addition, in the airflow flapping experiment, the maximum displacement in the second direction (T2 max ) is the maximum displacement in the second direction at the measurement point downstream of the airflow (T2 m ax ) It is preferable to provide two or more combinations of measurement points smaller than the above. This makes it possible to improve the reliability of the air blowing experiment.

[0055] Furthermore, in the air blowing experiment, it is preferable to change the distance D between the stone surface plate 11 and the pellicle film 3 and perform the experiment in the same way, so that the displacement amount of the pellicle film 3 satisfies the above condition for each distance. For example, in this embodiment, the distance D between the stone surface plate 11 and the pellicle film 3 at the center of the pellicle film 3 is changed to 5.5 mm, 8.0 mm, 10.0 mm, and 12.0 mm, and the experiment is performed in the same way. This ensures the structural stability of the pellicle film 3 even when conditions such as the distance between the photomask and the device components in the photolithography device change.

[0056] It is believed that the larger the pellicle 1, the greater the amount of displacement and flapping. Therefore, the pellicle 1 of this embodiment is preferable when the pellicle is large, such as when the length of the long side of the frame 2 is 600 mm or more and 4000 mm or less, and the length of the short side is 500 mm or more and 3000 mm or less, because the effects of the present invention can be more pronounced. In particular, the effects of the present invention can be more pronounced when the length of the long side of the frame 2 is 1700 mm or more and 4000 mm or less, and the length of the short side is 1600 mm or more and 3000 mm or less.

[0057] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the invention. For example, in this embodiment, the displacement (displacement direction, displacement amount) of the pellicle membrane was measured using a laser displacement meter, but any displacement meter other than a laser displacement meter may be used as long as it can measure the displacement of the pellicle membrane. In addition, in the above-described embodiment, a laser displacement meter was placed on the flat plate side and the displacement of the pellicle film was measured from above, but it is also possible to place a laser displacement meter on the stone surface plate side and measure the displacement of the pellicle film directly from below the pellicle film. [Example]

[0058] The present invention will now be described in more detail with reference to examples. However, the present invention is not limited to the following examples as long as it does not deviate from the gist of the invention. Physical properties in the examples were measured by the following methods. Unless otherwise specified, the fabrication of the pellicle and the air blowing experiment were carried out at room temperature (23°C).

[0059] [Fabrication of pellicle] <Example> (1) Preparation of a frame with an adhesive layer The frame was made of aluminum alloy and had a rectangular cross-section, measuring 1620 mm in outer diameter, 1780 mm in height, 6.5 mm in long side width, and 18.5 mm in short side width. The frame had a curved, bulging shape near the center of each side, with the initial outward convexity of 10.0 mm on the long side and 5.0 mm on the short side. The frame was then black anodized. Then, a 1.5 mm thick styrene ethylene butylene styrene rubber-based hot melt adhesive was applied to the bottom surface of the frame as a masking adhesive. A protective film (PET) was attached to the adhesive to protect the adhesive, creating a frame with adhesive.

[0060] (2) Preparation of pellicle membrane For the pellicle film, a polymer solution of cellulose ester was applied to low-alkali glass, and the main film was formed by closed-cup spin coating. Next, a fluoropolymer solution was spin-coated onto the main film to form an anti-reflection layer, forming a 4 μm-thick pellicle film, which was then uniformly transferred onto a temporary frame made of anodized aluminum alloy with external dimensions of 2000 mm x 2000 mm. The adhesive-coated frame prepared in (1) was pressed inward using a jig so that each side was approximately straight, and the pellicle film prepared in (2) was adhered to the frame using a film adhesive. After that, the external force applied by the jig was released from the short side, and then the external force applied by the jig from the long side was released to prepare a pellicle. The obtained pellicle membrane was attached to the upper end surface of an adhesive-backed frame via an adhesive, while appropriately adjusting the direction and magnitude of the tension applied to the pellicle membrane, to form the pellicle of the example.

[0061] [Air blowing experiment] The obtained pellicle was subjected to an air blowing test using the experimental apparatus shown in Figure 2. The laser displacement meter used was an NR-500 manufactured by KEYENCE Corp. Six laser displacement meters (P1 to P6) were placed at 300 mm intervals in the center of the pellicle membrane along the airflow direction (long side direction of the pellicle).

[0062] (1) The pellicle was attached to a flat plate via a mask adhesive. The pellicle, the object to be measured, was attached to the lower surface of the flat plate via an adhesive layer. The flat plate was an acrylic plate with a thickness of 5.0 mm and a size of 2000 mm x 2000 mm. Furthermore, an aluminum alloy reinforcement body was installed in a grid pattern on the upper side of the flat plate to suppress deflection of the flat plate. The distance between the stone surface plate (another flat plate) and the pellicle film was set to 5.5 mm. The size of the stone surface plate was 2500 mm x 2500 mm.

[0063] (2) Using a blower, air was blown along the long side of the pellicle, and the amount of displacement of the pellicle film in the thickness direction was measured. The air velocity of the fan was set to 1000 mm / s at the center of the pellicle membrane. Each set consisted of a 2-second blow followed by a 2-second interval, and this was repeated four times (for a total of 16 seconds).

[0064] The displacement (direction and amount of displacement) of the pellicle film at each point was measured using laser displacement meters P1 to P6 arranged along the airflow direction. Specifically, the displacement of the pellicle film was measured over the measurement time (airflow time) using an imaginary plane including one surface of the frame as a reference, and the displacement (T1) in a first direction toward the flat plate relative to the imaginary plane and the displacement (T2) in a second direction away from the flat plate were obtained.

[0065] FIG. 3 is a graph schematically showing the displacement of the pellicle membrane measured by each of the laser displacement meters P1 to P6. In Figure 3, 0 is a virtual plane that represents the pellicle membrane when stationary. This virtual plane is used as the reference plane for the displacement of the pellicle membrane. With respect to the reference plane (0), the upper side (+) of the graph represents displacement in a first direction toward the flat plate, and the lower side (-) of the graph represents displacement in a second direction away from the flat plate.

[0066] As can be seen from Figure 3, when the air blowing starts, the pellicle membrane flap due to the wind pressure. When the airflow is stopped (Blow off), it returns to its original position. The general trends in flapping were that on the upstream side of the airflow (P1-P2), the pellicle film tended to flap in a first direction relative to the reference plane. On the downstream side (P5-P6), the pellicle film tended to flap in a second direction relative to the reference plane. In the central area (P3-P5), the pellicle film tended to flap in both the first and second directions relative to the reference plane. Furthermore, the displacement is relatively large on the upstream side of the airflow, and relatively small on the downstream side. The displacement is particularly large in the central portion.

[0067] FIG. 4 shows the measurement results of the laser displacement meters P1 to P2 at the first measurement point (when Blow is on) in FIG. Figure 5 is a graph showing the displacement of the pellicle membrane measured at P6, and Figure 6 is a graph showing the displacement of the pellicle membrane measured by laser displacement meters P1 to P6 at the second measurement point in Figure 3 (at blow off). In Figures 4 and 5, measurement position 0 indicates the center of the pellicle membrane along the air blowing direction.

[0068] In FIG. 4 and FIG. 5, the maximum value of the displacement T1 in the first direction measured at P1 to P6 is T1 max The maximum value of the displacement T2 in the second direction measured at P1 to P6 was defined as T2 max It was decided. For example, the largest displacement in the first direction at the first point shown in Figure 4 is 0.96 [mm] measured at P2. max The largest displacement in the second direction was 1.70 mm measured at P5, and this value was set as T2 maxIt was decided.

[0069] In addition, in FIGS. 3 to 5, the displacement in the second direction is indicated by a minus (-) sign, but the values ​​of T1, T2, etc. defined in the present invention are absolute values ​​of the amount of displacement and are expressed as positive values.

[0070] The sum of the displacement amount in the first direction (T1) and the displacement amount in the second direction (T2) (Δ displacement amount=T1+T2) was 0.96 [mm]+1.70 [mm]=2.66 [mm].

[0071] In this embodiment, when calculating the Δ displacement, T1 and T2 are set as T1 max ,T1 m ax However, the values ​​are not limited to these.

[0072] In addition, the maximum displacement in the first direction (T1 max ) and the maximum displacement in the second direction (T2 m ax ) and the larger of these (amount of flapping) is T2 max The result was 1.70 [mm].

[0073] Similarly, at the second point shown in Figure 5, the displacement in the first direction is the largest at T1 max The displacement in the second direction was 2.29 mm measured at P2. max was measured at P6 and was 0.15 mm.

[0074] The sum of the displacement amount in the first direction (T1) and the displacement amount in the second direction (T2) (Δ displacement amount=T1+T2) was 2.29 [mm]+0.15 [mm]=2.44 [mm].

[0075] In addition, the maximum displacement in the first direction (T1 max ) and the maximum displacement in the second direction (T2 m ax ) and the larger of the two (amount of flapping) is T1 max The result was 2.29 [mm].

[0076] The same air blowing experiment was conducted by changing the distance between the stone surface plate and the pellicle film at the center of the pellicle film to 8.0 mm, 10.0 mm, and 12.0 mm.

[0077] As a comparative example, an adhesive-backed frame of the same size as in Example 1 was prepared, and a pellicle was fabricated in the same manner as in Example 1, except that the edges were adhered to the pellicle film without being pressed inward.The air blowing experiment was also carried out in the same manner, with the distance between the stone base and the pellicle film being 5.5 mm, 8.0 mm, 10.0 mm, and 12.0 mm.

[0078] In each case, the first measurement point (when Blow is on) and the second measurement point The maximum value (T1) of the displacements (T1, T2) of the pellicle membrane measured at a fixed point (at blow-off) max , T2 max ), T1 max +T2 max Tonowa (T1 max +T2 ma x ), and T1 max and T2 max The larger of (T max The results are summarized in Table 1.

[0079] [Table 1]

[0080] In the above-mentioned air blowing experiment, the pellicle of the embodiment (a) The sum of the displacement in the first direction (T1) and the displacement in the second direction (T2) (Δ displacement = T1 + T2) is 1.50 mm to 2.80 mm, and (b) Maximum displacement in the first direction (T1 max ) and the maximum displacement in the second direction (T2 max The larger of these (amount of flapping) was 1.00mm to 2.40mm. In the pellicles of the embodiments that satisfy both conditions for (a) the Δ displacement amount or (b) the amount of flapping, the tension of the pellicle film is appropriate, which suppresses distortion and deformation of the pellicle film and ensures structural stability.

[0081] In contrast, in the pellicle of the comparative example, at least one of (a) the Δ displacement amount and (b) the amount of flapping did not satisfy the above range.

[0082] Furthermore, the presence or absence of scratches on the pellicle film after the scratch test was confirmed as follows. That is, first, the pellicle film before the scratch test was visually inspected under a condenser light in a dark room to confirm that there were no scratches. Next, after the scratch test, the pellicle was removed from the flat plate and the presence or absence of scratches was visually inspected under a condenser light in a dark room. As a result, the pellicle membrane of the example had no scratches, but the pellicle membrane of the comparative example had scratches near P2 or P5.

[0083] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the invention. [Industrial Applicability]

[0084] By using the pellicle according to the present invention, the tension of the pellicle membrane and the stress of the frame are appropriate, distortion is suppressed, and structural stability can be ensured. This means that even large pellicles undergo little deformation when subjected to wind pressure caused by high-speed movement of the mask stage, making it possible to prevent changes in the optical properties of the pellicle film and prevent the pellicle film from coming into contact with the mask or equipment. [Explanation of symbols]

[0085] 1: Pellicle 2: Frame 3: Pellicle membrane 4: Adhesive layer 5: Release film 10: Experimental equipment 11: Stone surface plate 12: Flat plate 13: Blower P1~P6: Laser displacement gauge

Claims

1. A pellicle comprising a rectangular frame, a pellicle film provided on one side of the frame, and a mask adhesive provided on the other side of the frame, wherein the length of the long side of the frame is 600 mm or more and the length of the short side is 500 mm or more, Steps below: (1) attaching the pellicle to a flat plate via the mask adhesive; (2) providing a gap of 5.5 mm, 8.0 mm, 10.0 mm, or 12.0 mm between the pellicle and another flat plate; (3) A step of measuring the amount of displacement of the pellicle film in the thickness direction relative to a virtual plane including one surface of the frame body when stationary, over a predetermined measurement time when air is blown between the pellicle and the other flat plate at 1,000 mm / sec along the long side direction of the pellicle using a blower; and (4) obtaining a displacement amount in a first direction toward the flat plate and a displacement amount in a second direction away from the flat plate from the displacement amount; When conducting a ventilation experiment with The sum of the displacement amount (T1) in the first direction and the displacement amount (T2) in the second direction (Δ displacement amount = T1 + T2) is 1.50 mm to 2.80 mm, and The maximum displacement in the first direction (T1 ｍａｘ ) and the maximum displacement in the second direction (T2 ｍａ ｘ ) the larger of these (amount of flapping) is 1.00 mm to 2.40 mm.

2. The maximum displacement in the first direction (T1 ｍａｘ ) is the maximum displacement in the second direction (T2 ｍ ａｘ 10. The pellicle of claim 1, wherein the pellicle has a diameter greater than 100 nm.

3. The pellicle of claim 1, wherein the delta displacement amount and the flapping amount are obtained based on measurement results at multiple measurement points along the pellicle membrane in the air flapping experiment.

4. The pellicle described in claim 1, wherein in the air blowing experiment, two or more combinations of measurement points are provided where the maximum displacement in the first direction at the measurement point upstream of the air blowing is greater than the maximum displacement in the first direction at the measurement point downstream of the air blowing.

5. The pellicle described in claim 1, wherein in the air blowing experiment, two or more combinations of measurement points are provided in which the maximum displacement in the second direction at the measurement point upstream of the air blowing is smaller than the maximum displacement in the second direction at the measurement point downstream of the air blowing.

6. 2. The pellicle according to claim 1, wherein the length of the long side of the frame is 600 mm or more and 4000 mm or less, and the length of the short side is 500 mm or more and 3000 mm or less.

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