TW202340852A - Pellicle - Google Patents

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 ([Delta] 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

protective film

The present invention relates to a protective film.

In the world of photolithography, in addition to exposing small areas such as semiconductor IC (Integrated Circuit) wafers, one-time exposure technology has also been developed for larger areas such as flat panel displays such as liquid crystal displays. . In the manufacturing process of semiconductor components such as large-scale integrated circuits (LSI) and super-LSI, or liquid crystal display panels, the photosensitive layer, etc. is irradiated with light through an intervening mask (also called an exposure plate or reticle). Patterning. At this time, if there is a foreign object attached to the mask, the light will be absorbed by the foreign object, or the light will be reflected on the surface of the foreign object and deflected. As a result, the formed pattern is deformed or has rough edges, causing problems such as damage to the size, quality, and appearance after patterning. In order to eliminate this problem, a method is adopted in which a pellicle having a pellicle film that transmits light is mounted on the surface of the mask to suppress the adhesion of foreign matter (for example, Patent Document 1).

When such a protective film is installed on the mask, the air tightness inside the protective film is very high, and the protective film of the film may become loose or expanded due to changes in air pressure or temperature. When the pellicle film loses its smoothness, not only the optical properties of the pellicle film will change, but also when the degree of unevenness is severe, the pellicle film may sometimes come into contact with the mask or the device, resulting in Protective film damage. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2020-160466

[Problem to be solved by the invention]

Especially in large pellicles used in the manufacture of flat panel displays, it is difficult for the film tension to reach the center of the pellicle film. If the film tension is too small, deflection will easily occur in the central part of the film. If the film tension is too high, the stress on the frame will increase, making it difficult to ensure structural stability.

The present invention was proposed in view of this previous actual situation, and an object of the present invention is to provide a protective film in which the film tension of the protective film is appropriately adjusted, deformation caused by wind pressure, etc. is suppressed, and the structure is stable. Excellent performance. [Technical means to solve problems]

The invention is as follows. [1] A protective film, characterized by: having a rectangular casing, a protective film film provided on one side of the casing, and a mask adhesive provided on the other side of the casing, and the casing The length of the long side is more than 600 mm, and the length of the short side is more than 500 mm, and the following steps are performed: (1) The step of attaching the above protective film to the flat panel through the above mask adhesive; (2) ) Steps to set a distance of 5.5 mm, 8.0 mm, 10.0 mm or 12.0 mm between the above-mentioned protective film and another flat panel; (3) Based on the imaginary surface including one side of the above-mentioned housing at rest, use a blower to move along the When air is blown at 1,000 mm/second along the long side of the protective film between the protective film and the other flat plate, the displacement of the protective film in the thickness direction relative to the imaginary surface after a specific measurement time is measured. The steps of measuring; and (4) the steps of obtaining the displacement amount in the first direction close to the above-mentioned flat plate and the displacement amount in the second direction away from the above-mentioned flat plate among the above-mentioned displacement amounts; during the air supply flutter experiment, to the above-mentioned The sum of the displacement in the first direction (T1) and the displacement in the second direction (T2) (Δdisplacement = T1 + T2) is 1.50 mm ~ 2.80 mm, and the maximum displacement in the first direction (T1 _max ) and the maximum displacement in the second direction (T2 _max ), whichever is greater (the amount of vibration) is 1.00 mm to 2.40 mm. [2] The protective film according to [1], wherein the maximum displacement amount in the first direction (T1 _max ) is greater than the maximum displacement amount in the second direction (T2 _max ). [3] The protective film according to [1] or [2], wherein the Δ displacement amount and the vibration amount are based on the measurement results at a plurality of measurement points along the protective film film in the air blow vibration experiment. winner. [4] The protective film according to any one of [1] to [3], wherein in the above-mentioned air supply flutter experiment, two or more measuring points on the upstream side of the air supply are provided with the maximum value in the above-mentioned first direction. A combination of measurement points whose displacement amount is greater than the maximum displacement amount in the first direction at the measurement point on the downstream side of the air supply. [5] The protective film according to any one of [1] to [4], wherein in the above-mentioned air supply flutter experiment, two or more measuring points on the upstream side of the air supply are provided with the maximum value in the second direction. A combination of measurement points whose displacement amount is less than the maximum displacement amount in the second direction at the measurement point on the downstream side of the air supply. [6] The protective film according to any one of [1] to [5], wherein the length of the long side of the housing is not less than 600 mm and not more than 4000 mm, and the length of the short side is not less than 500 mm and not more than 3000 mm. . [Effects of the invention]

According to the present invention, it is possible to provide a pellicle in which the film tension of the pellicle film is appropriately adjusted, deformation caused by wind pressure, etc. is suppressed, and the structure stability is excellent.

Hereinafter, a mode for implementing the present invention (hereinafter simply referred to as "embodiment") will be described with reference to the drawings. The present invention is not limited to the following embodiments, and can be implemented with various changes within the scope of the spirit. In each drawing, the same components are assigned the same symbols, and repeated descriptions may be omitted.

An outline of the protective film according to this embodiment will be described. FIG. 1(a) is a top view of the protective film 1, and FIG. 1(b) is a longitudinal sectional view. In addition, in the following description, the upper side in each figure is referred to as "upper", and the lower side is referred to as "lower". Similarly, in each figure, the right side is referred to as "right" and the left side is referred to as "left" for explanation. In addition, the numerical range expressed by "～" in this specification includes the upper limit and the lower limit.

＜Protective film＞ The protective film 1 is a structure used to prevent dust from the photomask in photolithography and the like. The pellicle 1 includes a rectangular casing 2, a pellicle film 3 provided on one side of the casing 2, an adhesive layer 4 provided on the other side of the casing 2, and a release film 5.

The casing 2 (pellicle frame) may have any shape that allows the pellicle film 3 to be stretched on the casing 2. For example, it may have a rectangular shape when viewed from the front of the casing. The rectangle can be a square, a rectangle, etc., and can have both a case where the corners are right angles and a case where the corners are roughly rectangular (Fig. 1).

The size of the housing 2 and its opening can be set according to the size of the photomask. When the shell 2 has a rectangular shape including a pair of long sides and a pair of short sides when viewed from the front, the length of the long side can be 600 mm ~ 4000 mm, 600 mm ~ 3000 mm or 600 mm ~ 2000 mm. The side length can be 500 mm ~ 3000 mm, 500 mm ~ 2000 mm or 500 mm ~ 1800 mm, the width of the long side and the short side can be 4.0 mm ~ 20.0 mm respectively, and/or the height of the shell can be 2.0 mm ~ 10.0 mm. In particular, the protective film 1 of this embodiment is preferably a large protective film in which the length of the long side of the housing 2 is more than 600 mm and the length of the short side is more than 500 mm. More preferably, the protective film 1 is a long side of the housing 2. The length is more than 1700 mm, and the length of the short side is more than 1600 mm.

As shown in FIG. 1 , the housing 2 has an edge portion. The edge portion may have a linearly extending rod-shaped edge member. A pair of edge members may be spaced apart from each other and arranged in parallel. Similarly, the other pair of edge members may be spaced apart from each other and arranged in parallel. The ends of two contacting edge members can be connected at approximately right angles to each other.

The housing 2 and its edge members may be formed of, for example, the following known materials: aluminum; aluminum alloys (such as 5000 series, 6000 series, 7000 series, etc.); titanium; titanium alloys; steel; stainless steel; magnesium alloys; ceramics (such as SiC, AIN , Al ₂ O ₃ , etc.); composite materials of ceramics and metals (such as Al-SiC, Al-AlN, Al-Al ₂ O _3, etc.); PE (Polyethylene, polyethylene), PA (Polyamide, polyamide), Engineering plastics such as PC (Polycarbonate, polycarbonate), PEEK (Poly (ether-ether-ketone), polyether ether ketone); GFRP (Glass Fiber Reinforced Plastics, glass fiber reinforced plastics), CFRP (Carbon Fiber Reinforced Plastics, carbon fiber Reinforced plastic) and other fiber composite materials; or combinations thereof, etc.

The lower limit of the thickness of the housing 2 is preferably 3.0 mm or more, more preferably 3.5 mm or more, and further preferably 4.0 mm or more. On the other hand, the upper limit of the thickness of the housing 2 is preferably 10.0 mm or less, more preferably 8.0 mm or less, and further preferably 7.0 mm or less.

The width of the housing 2 is preferably between 3.5 mm and 30 mm. Being within this range ensures an effective exposure area and can withstand the tension of the pellicle film 3, so it is preferable. The lower limit of the width of the housing 2 is preferably at least 4.0 mm, further preferably at least 6.0 mm, further preferably at least 12.0 mm, and is preferably changed according to the area of the housing 2 in a manner that can withstand film tension. Especially when the length of the long side is 1700 mm or more and the length of the short side is 1600 mm or more, the width of the casing 2 is preferably 15.0 mm or more. On the other hand, the upper limit of the width of the housing 2 is more preferably 25 mm or less, and further preferably 20 mm or less. Furthermore, regarding the width of the housing 2, the widths of either the long side and the short side may be the same, or the long side and the short side may have independent widths.

The inner circumferential surface or the entire surface of the housing 2 may be coated with adhesive (such as acrylic, vinyl acetate, silicone, rubber, etc.) or grease (such as silicone) to capture foreign matter if necessary. Ketone series, fluorine series grease, etc.).

The protective film 3 is a transparent film. The thickness of the protective film 3 is 10 μm or less, and is formed to fully transmit the light emitted by the light source during photolithography. In particular, the thickness is preferably 2.0 μm to 4.5 μm.

The material constituting the pellicle film 3 is not particularly limited, and examples thereof include nitrocellulose, cellulose derivatives, fluoropolymers, carbon materials, and the like. Among them, carbon materials are preferred.

As shown in FIG. 1(b) , the protective film 3 is adhered and fixed to one end side of the housing 2 by an adhesive (not shown), covering the housing 2 .

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 housing 2 (the side of the housing 2 opposite to the pellicle film 3 ).

The adhesive layer 4 (mask adhesive layer) is composed of adhesives such as acrylic, rubber, vinyl, epoxy, silicone, etc., and more preferred materials are acrylic, rubber, silicone, etc. The thickness of the adhesive layer 4 is preferably 0.8 mm to 3.0 mm, for example.

The release film 5 (liner) is arranged so as to cover the adhesive layer 4 . The peeling film 5 protects the adhesive layer 4 when not in use, and peels off from the adhesive layer 4 when the protective film 1 is in use. As for the release film 5, a film having a thickness of about 30 μm to 200 μm, such as polyester, is usually used. In addition, if the peeling force when peeling off the peeling film 5 from the adhesive layer 4 is large, there is a risk that the adhesive layer 4 will be deformed during peeling. Therefore, in order to achieve an appropriate peeling force, silicone can be applied to the surface of the film that is in contact with the adhesive. Ketone or fluorine plasma treatment.

The release film 5 has a width larger than that of the adhesive layer 4 and is configured to extend from the adhesive layer 4 to the outer peripheral side of the housing 2 .

In addition, for the pellicle 1 of this embodiment, the tension of the pellicle film 3 is appropriately adjusted so that the displacement amount and the tremble amount when performing the air blow flutter test shown below are within a specific range. Thereby, in the pellicle 1 of this embodiment, the appropriate film tension reaches the central part of the pellicle film 3, suppressing the deflection of the central part of the pellicle film 3, and the stress on the housing 2 is also appropriate. Suppressing the occurrence of strain ensures structural stability even for large-scale protective films.

<Air flow flutter test> Hereinafter, the air flow flutter test defined in the present invention will be described. The supply air flutter experiment has the following steps. (1) Steps of attaching the protective film 1 to the flat plate 12 (flat plate) through the adhesive layer 4; (2) Set 5.5 mm, 8.0 mm, 10.0 between the protective film 1 and the pressure plate 11 (another flat plate) mm or 12.0 mm intervals; (3) Using the imaginary surface including one side of the housing 2 at rest as a reference, use the air blower 13 to blow air at 1,000 mm/second along the long side of the protective film 1, and measure the elapsed time Steps for measuring the displacement amount of the pellicle film 3 in the thickness direction relative to the imaginary surface at a specific time; and (4) obtaining the maximum displacement amount (T1 _max ) in the first direction approaching the flat plate 12 among the displacement amounts, and The steps of maximum displacement (T2 _max ) in the second direction away from the flat plate; Each step is explained below.

(1) Attach the protective film 1 to the flat panel through the adhesive layer 4 (mask adhesive layer). 2 is a diagram schematically showing a configuration example of an experimental device for measuring the flutter amount of the pellicle film 3 (air flow flutter test) in the present invention, with (a) being a top view and (b) being a side view.

The experimental device 10 of the air flow vibration experiment includes: a stone pressure plate 11; a flat plate 12 (flat plate) arranged at a specific distance above the stone pressure plate 11 and substantially parallel to the stone pressure plate 11; A plurality of laser displacement meters P1 to P6 on the opposite side to the side facing the pressure plate 11 (another flat plate); and an air blower 13 that blows air toward the space between the stone pressure plate 11 and the flat plate 12 . From the viewpoint of air supply stability, the stone pressure plate 11 is preferably one with specific flatness, and from the viewpoint of structural stability, the stone pressure plate 11 is preferably one with specific rigidity.

Regarding the flat plate 12, since the displacement of the pellicle film 3 is measured by the laser displacement meters P1 to P6, it is necessary to cut the flat plate into the shape of the laser displacement meter so that the laser displacement meters P1 to P6 can measure it, and it can In order to visualize the condition of the pellicle film, a material that is transparent and easy to process is preferred. Acrylic boards are particularly preferred. During the air supply flutter experiment, the protective film 1 is attached to the lower side of the flat plate 12 through the adhesive layer 4 .

The size of the stone pressure plate 11 and the flat plate 12 is not particularly limited and is determined by the measured size of the protective film 1, which is usually larger than the protective film 1. In this embodiment, the size of the protective film 1 is 1780 mm on the long side × 1620 mm on the short side, and the size of the flat plate 12 is 2000 mm × 2000 mm. In addition, the size of the stone pressure plate 11 is preferably larger than the flat plate 12 .

If the pellicle 1 becomes larger, for example, with a long side of 1700 mm or more, the problem of fluttering of the pellicle film 2 becomes significant. That is, as the pellicle film 1 becomes larger, the deflection or vibration of the pellicle film 3 itself also becomes larger. Even in the exposure device, if the distance between parts becomes narrower and the movement of the mask table becomes faster and more complicated, Then the influence of the deflection or vibration of the pellicle film 3 will also become greater, and the possibility that the pellicle film 3 will be damaged due to contact with the mask or parts becomes higher. If the protective film is damaged, it will cause adverse effects such as focus shift during exposure.

Therefore, the air supply vibration experiment in the present invention targets a large protective film with a long side of the casing 2 of at least 1700 mm. The present invention is a large-scale protective film with a long side of the casing 2 of at least 1700 mm. Taking into account the influence of wind pressure caused by the high-speed movement of the masking table, the protective film is reduced in a way that the influence of vibration is reduced. 3. Optimizing the tension, etc., if only increasing the size of the previous protective film, the effect of the present invention cannot be obtained.

An air blower 13 is arranged outside the flat plate 12 and the stone pressure plate 11 . The air blower 13 is a device that blows air to the space between the protective film 1 attached to the flat plate 12 and the stone pressure plate 11 . In the example shown in FIG. 2 , the air blower 13 blows the air W at a specific wind speed from the left to the right in the figure.

Laser displacement meters P1 to P6 are devices for measuring the displacement (direction and amount of displacement) of the protective film 3 during air supply, and are arranged on the side of the flat plate 12 opposite to the side where the protective film 1 is attached. It is preferable to set a plurality of measurement points of the laser displacement meters P1 to P6. In this embodiment, six laser displacement meters P1 to P6 are arranged at intervals of 300 mm along the air supply direction in the center of the pellicle film 3 .

In this experimental device, the peeling film 5 is peeled off, and the protective film 1 serving as the object to be measured is affixed so that the exposed adhesive layer 4 faces the lower surface of the flat plate 12 .

(2) Set a distance of 5.5 mm, 8.0 mm, 10.0 mm or 12.0 mm between the protective film 1 and the stone pressure plate 11 (another flat plate). The distance D between the protective film 1 attached to the flat plate 12 and the stone platen 11 can be appropriately set according to the distance between the protective film 1 and the device components of the protective film 1 in the actual lithography device used. In this embodiment, the distance D is set to 5.5 mm to 12.0 mm.

(3) Use the air blower 13 to blow air along the pellicle 1 and measure the displacement of the pellicle film 3 in the thickness direction. The air blower 13 was used to blow air toward the space between the pellicle film 3 and the stone pressure plate 11, and the displacement amount of the pellicle membrane 3 caused by the wind pressure was measured.

In this embodiment, the wind speed of the air blower 13 is set to 1000 mm/second at the center of the pellicle film 3 . The air supply system sets the air supply of 2 seconds and the interval of 2 seconds as one set, and repeats this 4 times. By using six laser displacement meters P1 to P6 arranged along the air supply direction, the displacement (direction of displacement and amount of displacement) of the pellicle film 3 at each location is measured.

Specifically, the displacement of the pellicle film 3 is based on an imaginary plane including one side of the housing 2 at rest. This imaginary surface represents the pellicle film 3 at rest.

Then, after a specific measurement time (air blowing time), the displacement amount (T1) in the first direction approaching the flat plate 12 and the displacement amount (T2) in the second direction away from the flat plate 12 relative to the imaginary surface are obtained. In FIG. 2(b) , the first direction is the direction from the imaginary surface to the upper side, and the second direction is the direction from the imaginary surface to the lower side.

(4) Obtain the maximum displacement amount in the first direction toward the plane (T1 _max ) and the maximum displacement amount in the second direction away from the plane (T2 _max ) among the displacement amounts. Obtain the maximum displacement amount (T1 max ) among the displacement amounts in the first direction (T1) obtained in the above ₍ 2) step, and the maximum displacement amount (T2 _max ) among the displacement amounts in the second direction (T2). ).

Furthermore, in the protective film 1 of this embodiment, (a) 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) is 1.50 mm to 2.80 mm, and (b) the greater of the maximum displacement in the first direction (T1 _max ) and the maximum displacement in the second direction (T2 _max ) (the amount of vibration) is 1.00 mm to 2.40 mm.

Thereby, even if the pellicle film 3 is subject to wind pressure due to movement of the masking table, etc., the deformation (displacement or vibration) of the pellicle film 3 can be suppressed, thereby reducing the risk of the pellicle film 3 coming into contact with the mask or device parts. .

The amount of displacement or vibration of the pellicle film 3 can be adjusted to the above range by appropriately adjusting the film tension of the pellicle film 3 . Specifically, for example, a method of appropriately adjusting the direction or magnitude of the tension applied to the pellicle film 3 when attaching the pellicle film 3 to the housing 2 can be exemplified.

Specifically, for example, as the case 2, a pair of edges bulged outward is used, and when the pellicle film 3 is attached to the case 2, the bulged edges are directed toward the inside of the case 2. In the state of elastic deformation, the protective film 3 is attached and flattened, so that the restoring force of the housing 2 and the flattening force of the protective film 3 can be easily balanced. At this time, by adjusting the bulging amount of the edge portion to a specific range, the direction or magnitude of the tension applied to the pellicle film 3 can be appropriately adjusted. Furthermore, by making the case 2 contain a material with a Young's modulus in a specific range, when the pellicle film 3 is attached to the case 2, the case 2 can be appropriately balanced in a state of being in a substantially rectangular shape. The restoring force of the shell 2 and the film tension of the protective film 3. In this case, a material having a Young's modulus of 100 MPa or more is preferred.

Alternatively, when attaching the pellicle film 3 to the casing 2 , it is performed in an environment where the humidity is the same as or higher than the humidity in the exposure device. This can also maintain the stress of the pellicle film 3 is smaller, the tension given to the protective film 3 can be appropriately adjusted.

(a) If the sum of the displacement amounts T1 and T2 or (b) the vibration amount is greater than the above range, the tension on the pellicle film 3 is low, and the central part of the pellicle film 3 may be deflected. In addition, if (a) the sum of the displacement amounts T1 and T2 or (b) the vibration amount is smaller than the above range, the pellicle film 3 is subjected to excessive tension, and the casing 2 may be subjected to a large stress and cause strain.

From the viewpoint of suppressing the deformation of the pellicle film 3 and achieving a balance between the tension of the pellicle film 3 and the stress of the case 2, both (a) and (b) need to be satisfied. Thereby, in the pellicle 1 of this embodiment, the appropriate film tension reaches the central part of the pellicle film 3, suppressing the deflection of the central part of the pellicle film 3, and the stress on the casing 2 is also appropriate. Suppresses the generation of strain and has excellent structural stability.

(a) The Δ displacement (=T1+T2) is preferably more than 1.50 mm and less than 2.80 mm, more preferably 1.60 mm to 2.70 mm. Moreover, (b) the vibration amount is preferably more than 1.00 mm and less than 2.40 mm, more preferably 1.10 mm to 2.35 mm. Thereby, the structural stability of the protective film 1 can be improved.

Furthermore, the Δ displacement amount and the flutter amount are preferably obtained based on the measurement results at a plurality of measurement points along the pellicle film 3 in the blower flutter experiment. Of course, the behavior in the air supply flutter experiment is also different at the ends and the center of the pellicle film 3, the upstream side and the downstream side of the air supply. By setting up not just one measurement point, but multiple measurement points, the movement of each location on the entire mulch 1 can be understood in more detail, thereby improving the reliability of the air supply flutter experiment and suppressing the displacement and flutter of the entire mulch. smaller.

Furthermore, in the air supply flutter experiment, it is preferable to set up two or more places where the maximum displacement amount (T1 _max ) in the first direction at the measuring point on the upstream side of the air supply is larger than that in the first direction at the measuring point on the downstream side of the air supply. The combination of measuring points for the maximum displacement in the direction (T1 _max ). In this way, the reliability of the air supply flutter experiment can be improved.

Furthermore, in the air supply flutter experiment, it is preferable to set up two or more places where the maximum displacement amount (T2 max ) in the second direction at the measurement point on the upstream side of the air supply is smaller than the maximum displacement in the second direction (T2 _max ) at the measurement point on the downstream side of the air supply. The combination of measuring points for the maximum displacement in the direction (T2 _max ). In this way, the reliability of the air supply flutter experiment can be improved.

Furthermore, in the air flow flutter test, it is preferable to change the distance D between the stone pressure plate 11 and the pellicle film 3 and perform the experiment in the same manner, assuming that the displacement of the pellicle membrane 3 is maintained at each interval. The quantity satisfies the above conditions. For example, in this embodiment, the distance D between the stone platen 11 in the center of the protective film 3 and the protective film 3 is changed to 5.5 mm, 8.0 mm, 10.0 mm, or 12.0 mm, and the experiment is performed in the same manner. Thereby, even when conditions such as the distance between the photomask and the device parts in the photolithography device change, the structural stability of the pellicle film 3 can be ensured.

It is considered that the larger the protective film 1 is, the greater the amount of displacement or vibration becomes. Therefore, when the protective film 1 of this embodiment is a large protective film such that the length of the long side of the housing 2 is not less than 600 mm and not more than 4000 mm, and the length of the short side is not less than 500 mm and not more than 3000 mm, it can be used The effect of the present invention is more significant, so it is better. In particular, when the length of the long side of the housing 2 is from 1,700 mm to 4,000 mm, and the length of the short side is from 1,600 to 3,000 mm, the effect of the present invention can be further enhanced.

The embodiments of the present invention have been described above. However, the present invention is not limited thereto and may be appropriately modified within the scope of the invention. For example, in this embodiment, a laser displacement meter is used to measure the displacement (direction of displacement, amount of displacement) of the pellicle film. However, as long as it can measure the displacement of the pellicle film, it may be other than a laser displacement meter. Displacement meter. Moreover, in the above embodiment, the laser displacement meter is arranged on the side of the flat plate and the displacement of the protective film is measured from the upper side. However, the laser displacement meter can also be arranged on the side of the stone plate and measured directly from the lower side of the protective film. Measure the displacement of the protective film. [Example]

Next, an Example is given and this invention is demonstrated more concretely. However, the present invention is not limited to the following examples unless it deviates from the gist of the invention. The physical properties in the examples were measured by the following methods. In addition, unless otherwise specified, the production of the protective film and the air flow vibration test are performed at room temperature (23°C).

[Production of protective film] <Example> (1) Preparation of shell with adhesive layer The outer diameter is 1620 mm×1780 mm×height 6.5 mm, the long side width is 16.5 mm, and the short side width is 18.5 mm. The material is made of aluminum alloy, and the cross-sectional shape of the shell is a rectangular shape. The housing is curved and bulged in such a way that the center of each side protrudes outward. The outward protrusion of the initial shape is 10.0 mm on the long side and 5.0 on the short side. mm. Then, the used casing is treated with a black aluminum oxide film. Afterwards, a 1.5 mm thick styrene-ethylene-butylene-styrene rubber-based hot-melt adhesive was applied to the lower end surface of the shell as a mask adhesive material. In order to protect the adhesive, a protective film (PET) is attached to the adhesive to form an adhesive-attached case.

(2) Production of protective film As a protective film, a polymer solution of cellulose ester is coated on low-alkali glass, and a closed cup spin coating is used to form a main film. Then, the fluoropolymer solution was coated on the main film by spin coating to form an anti-reflective layer with a thickness of 4 μm and the protective film was transferred to an aluminum oxide film-treated surface with an outer size of 2000 mm × 2000 mm. The aluminum alloy mold frame is prepared in the same way. While using a jig to press inward the sides of the adhesive-coated casing made in (1) so that each edge is roughly straight, adhere the protective film made in (2) through the film adhesive. in the above casing. Thereafter, the external force caused by the jig is released from the short side part side, and then the external force caused by the jig is released from the long side part side, and a protective film is produced. The direction or size of the tension applied to the pellicle film is appropriately adjusted, and the pellicle film obtained is attached to the upper end surface of the adhesive-attached case via an adhesive, thereby producing a pellicle of the embodiment.

[Air supply flutter experiment] For the obtained protective film, the experimental device shown in Figure 2 was used to conduct an air supply flutter experiment. Use NR-500 manufactured by KEYENCE Company as the laser displacement meter. Six laser displacement meters (P1 to P6) are arranged at intervals of 300 mm in the center of the pellicle film along the air supply direction (the long side direction of the pellicle).

(1) Attach the protective film to the flat panel (flat panel) via mask adhesive. The intervening adhesive layer attaches the protective film as the object to be measured to the lower side of the flat plate. The flat plate is an acrylic plate with a thickness of 5.0 mm and a size of 2000 mm × 2000 mm. Furthermore, in order to suppress the deflection of the flat plate, aluminum alloy reinforcements are provided on the upper side of the flat plate in a lattice shape. Then, set the distance between the stone pressure plate (another flat plate) and the protective film to 5.5 mm. The size of the stone pressure plate is 2500 mm×2500 mm.

(2) Use an air blower to blow air along the long side of the protective film, and measure the displacement of the protective film in the thickness direction. The wind speed of the air blower is set to 1000 mm/second at the center of the pellicle film. The air supply system consists of a set of 2 seconds of air supply and 2 seconds of interval, and repeats this 4 times (a total of 16 seconds).

By using laser displacement meters P1 to P6 arranged along the air supply direction, the displacement (direction of displacement and amount of displacement) of the pellicle film at each location is measured. Specifically, as the displacement of the pellicle film, the displacement amount (T1) in the first direction close to the flat plate with respect to the imaginary surface is obtained after the measurement time (air blowing time) is based on the imaginary plane including one surface of the casing, and The amount of displacement in the second direction away from the plate (T2).

FIG. 3 is a diagram schematically showing the displacement of the pellicle film measured by each of the laser displacement meters P1 to P6. In Figure 3, 0 is an imaginary surface, representing the protective film at rest. This imaginary plane is used as the reference plane for the displacement of the pellicle film. Relative to the datum plane (0), the upper side (+) of the figure indicates the displacement in the first direction closer to the flat plate, and the lower side (-) of the figure indicates the displacement in the second direction away from the flat plate.

According to Figure 3, it can be seen that when the air blowing starts (Blow on), the protective film vibrates and shifts due to the wind pressure, and when the air blowing stops (Blow off), it returns to its original state. As a general tendency of the vibration, on the upstream side (P1 to P2) of the air supply, the tendency of the pellicle film to vibrate in the first direction relative to the reference plane was observed. On the downstream side (P5 to P6), a tendency of the pellicle film to vibrate in the second direction relative to the reference plane was observed. In the central portion (P3 to P5), a tendency of the pellicle film to vibrate in both the first and second directions relative to the reference plane was observed. In addition, the displacement on the upstream side of the air supply is relatively large, and the displacement on the downstream side is relatively small. The displacement in the central part is particularly large.

Figure 4 is a graph showing the displacement of the pellicle film measured by laser displacement meters P1 to P6 at the first measurement point in Figure 3 (when blowing on). Figure 5 is a graph showing the displacement of the pellicle film in Figure 3 At the second measurement point (when Blow off), the displacement of the pellicle film measured by laser displacement meters P1 to P6 is shown. In Figures 4 and 5, the measurement position 0 represents the center of the pellicle film along the air supply direction.

In FIGS. 4 and 5 , the maximum value of the displacement amounts T1 in the first direction measured using P1 to P6 is set to T1 _max . Moreover, let the maximum value among the displacement amounts T2 in the second direction measured using P1 to P6 be T2 _max . For example, at the first point shown in Figure 4, the maximum displacement amount in the first direction is 0.96 [mm] measured using P2, and this value is set to T1 _max . In addition, the maximum displacement amount in the second direction is 1.70 [mm] measured by P5, and this value is set to T2 _max .

Furthermore, in Figures 3 to 5, the displacement in the second direction is expressed as negative (-), but the values of T1, T2, etc. specified in the present invention are the absolute values of the displacement and are expressed as positive values.

Furthermore, 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) is 0.96 [mm] + 1.70 [mm] = 2.66 [mm].

Furthermore, in this embodiment, when calculating the Δ displacement, the values of T1 _max and T1 _max are respectively used as T1 and T2, but they are not limited to this.

In addition, the larger of the maximum displacement amount in the first direction (T1 _max ) and the maximum displacement amount in the second direction (T2 _max ) (vibration amount) is 1.70 [mm] of T2 _max .

Similarly, at the second point shown in Figure 5, T1 _max , which has the largest displacement in the first direction, is 2.29 [mm] measured using P2. In addition, T2 _max, which has the largest displacement amount in the second direction, is 0.15 [mm] measured using P6.

Furthermore, 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) is 2.29 [mm] + 0.15 [mm] = 2.44 [mm].

In addition, the larger of the maximum displacement amount in the first direction (T1 _max ) and the maximum displacement amount in the second direction (T2 _max ) (vibration amount) is 2.29 [mm] of T1 _max .

Change the distance between the stone pressure plate in the center of the protective film and the protective film to 8.0 mm, 10.0 mm, and 12.0 mm, and conduct the air supply flutter experiment in the same way.

Furthermore, as a comparative example, a case with adhesive attached of the same size as in Example 1 was prepared, and other than that each edge was adhered to the protective film without being pressed inward, the protective film was produced in the same manner as in Example 1. membrane, set the distance between the stone pressure plate and the protective film to 5.5 mm, 8.0 mm, 10.0 mm, and 12.0 mm, and conduct the air supply flutter experiment in the same way.

In addition, for each case, the maximum value (T1 _max , T2 ) of the displacement amounts (T1, T2) of the pellicle film measured at the first measurement point (when Blow on) and the second measurement point (when Blow off) were measured. _max ), the sum of T1 _max + T2 _max (T1 _max + T2 _max ), and the larger of T1 _max and T2 _max (T _max : tremor amount) are shown in Table 1 together.

[Table 1] Spacing[mm] Wind speed [mm/second] Displacement[mm] 1st measuring point (Blow on) 2nd measuring point (Blow off) T1 _max T2 _max T1 _max + T2 _{max Tmax} T1 _max T2 _max T1 _max + T2 _{max Tmax} Example 5.5 1.000 0.96 1.70 2.66 1.70 2.29 0.15 2.44 2.29 8.0 1.000 1.45 0.79 2.24 1.45 2.04 0.16 2.20 2.04 10.0 1.000 1.30 0.74 2.04 1.30 1.52 0.14 1.66 1.52 12.0 1.000 1.19 0.89 2.08 1.19 1.63 0.21 1.84 1.63 Comparative example 5.5 1.000 1.12 2.00 3.12 2.00 2.69 0.18 2.87 2.69 8.0 1.000 1.71 0.93 2.64 1.71 2.40 0.19 2.59 2.40 10.0 1.000 1.53 0.88 2.41 1.53 1.79 0.15 1.94 1.79 12.0 1.000 1.39 1.05 2.44 1.39 1.92 0.25 2.17 1.92

In the air supply flutter test as described above, in the protective film of the example, (a) the sum of the displacement amount in the first direction (T1) and the displacement amount in the second direction (T2) (Δ displacement = T1 + T2 ) is 1.50 mm ~ 2.80 mm, and (b) the greater of the maximum displacement amount in the first direction (T1 _max ) and the maximum displacement amount in the second direction (T2 _max ) (the vibration amount) is 1.00 mm ~ 2.40mm. In the pellicle of the embodiment that satisfies both conditions regarding (a) Δ displacement or (b) tremor amount, the tension of the pellicle film is appropriate, the strain or deformation of the pellicle film is suppressed, and the structural stability is ensured. .

On the other hand, in the protective film of the comparative example, at least one of (a) the Δ displacement amount and (b) the vibration amount does not satisfy the above range.

Furthermore, the presence or absence of damage to the pellicle film after the flutter test was confirmed in the following manner. That is, first, the pellicle film before the flutter test was irradiated with a spotlight in a dark room to visually confirm that there was no damage. Then, after the vibration test, the protective film was removed from the flat panel, and a spotlight was irradiated in a dark room to visually confirm whether there was any damage. As a result, the pellicle film of the Example was not damaged, but the pellicle film of the Comparative Example was damaged near P2 or P5.

The embodiments of the present invention have been described above. However, the present invention is not limited thereto and may be appropriately modified within the scope of the invention. [Industrial availability]

By using the protective film of the present invention, the tension of the protective film or the stress of the housing can be made appropriate, strain can be suppressed, and structural stability can be ensured. This allows small deformation of large-sized pellicles even under the influence of wind pressure caused by high-speed movement of the masking table, thereby suppressing changes in the optical properties of the pellicle film or the movement of the pellicle film to the mask. or device contact.

1: Protective film 2: Shell 3: Protective film 4:Adhesive layer 5: Peel off film 10: Experimental device 11: Stone pressure plate 12: Tablet 13: Blower D: Space between stone pressure plate 11 and protective film 3 P1~P6: Laser displacement meter W: wind

FIGS. 1(a) and 1(b) are diagrams showing a structural example of a protective film. 2 (a) and (b) are diagrams schematically showing an example of the configuration of an experimental device used in the air supply flutter experiment. FIG. 3 is a diagram schematically showing the displacement of the pellicle film measured by each of the laser displacement meters P1 to P6. FIG. 4 is a diagram showing the displacement amount of the pellicle film measured at the first measurement point using laser displacement meters P1 to P6 in the embodiment. FIG. 5 is a graph showing the displacement amount of the pellicle film measured at the second measurement point using laser displacement meters P1 to P6 in the embodiment.

1: Protective film

2: Shell

3: Protective film

4:Adhesive layer

10: Experimental device

11: Stone pressure plate

12: Tablet

13: Blower

D: Space between stone pressure plate 11 and protective film 3

P1~P6: Laser displacement meter

W: wind

Claims (6)

A protective film, characterized by: having a rectangular casing, a protective film film disposed on one side of the casing, and a mask adhesive disposed on the other side of the casing, and the long side of the casing The length is more than 600 mm, and the length of the short side is more than 500 mm, and the following steps are performed: (1) The step of attaching the above-mentioned protective film to the flat panel through the above-mentioned mask adhesive; (2) The above-mentioned steps Steps to set a gap of 5.5 mm, 8.0 mm, 10.0 mm or 12.0 mm between the protective film and another flat panel; (3) Based on the imaginary surface including one side of the above-mentioned housing at rest, use an air blower to move along the above-mentioned protective film. The step of measuring the displacement of the above-mentioned pellicle film in the thickness direction relative to the above-mentioned imaginary surface after a specific measurement time when air is blown at 1,000 mm/second between the above-mentioned pellicle and the above-mentioned other flat plate in the longitudinal direction of the film. ; and (4) the step of obtaining the displacement amount in the first direction close to the above-mentioned flat plate and the displacement amount in the second direction away from the above-mentioned flat plate among the above-mentioned displacement amounts; During the air supply flutter experiment, to the above-mentioned first direction The sum of the displacement in the direction (T1) and the displacement in the second direction (T2) (Δdisplacement = T1 + T2) is 1.50 mm ~ 2.80 mm, and the maximum displacement in the first direction (T1 _max ) is equal to The larger of the maximum displacement amounts (T2 _max ) in the above-mentioned second direction (tremor amount) is 1.00 mm to 2.40 mm. The protective film of claim 1, wherein the maximum displacement amount in the above-mentioned first direction (T1 _max ) is greater than the maximum displacement amount in the above-mentioned second direction (T2 _max ). The protective film of claim 1, wherein the Δ displacement amount and the vibration amount are obtained based on the measurement results at a plurality of measurement points along the protective film film in the air supply vibration experiment. Such as the protective film of claim 1, wherein in the above-mentioned air supply flutter experiment, the maximum displacement amount in the first direction at the measuring point on the upstream side of the air supply is greater than that at the measuring point on the downstream side of the air supply. The combination of the measurement points of the maximum displacement amount in the first direction. Such as the protective film of claim 1, wherein in the above-mentioned air supply flutter experiment, the maximum displacement amount in the second direction at the measuring point on the upstream side of the air supply is smaller than that at the measuring point on the downstream side of the air supply. The combination of the measurement points of the maximum displacement amount in the above-mentioned second direction. Such as the protective film of claim 1, wherein the length of the long side of the above-mentioned housing is not less than 600 mm and not more than 4000 mm, and the length of the short side is not less than 500 mm and not more than 3000 mm.