Pellicle, original plate for exposure, exposure apparatus, method of producing semiconductor device, and method of producing semiconductor device

Abstract

The protective film assembly of the present invention includes a support frame having an opening and a protective film. The protective film has a self-supporting film region covering the opening. The self-supporting film region includes an exposure region and a peripheral region surrounding the exposure region. The peripheral region has a thick film portion that is thicker than the film thickness of the exposure region. The protective film assembly satisfies either (i) or (ii) below: (i) The support frame is a rectangular frame, and the thick film portion is located at least in a pair of defined long side regions of the peripheral region. (ii) The support frame is a square frame, and the thick film portion is located at least in a pair of defined first central regions and a pair of defined second central regions of the peripheral region.

Description

[Technical Field]

[0001] This disclosure relates to a protective film assembly, an exposure original, an exposure apparatus, a method for manufacturing the protective film assembly, and a method for manufacturing a semiconductor device. [Previous Technology]

[0002] In the technique of forming a pattern by coating the surface of objects such as electronic components, printed circuit boards, and display panels with a photosensitive substance and exposing it to form a pattern (photolithography), a transparent substrate with a pattern formed on one side is used, which is called a photomask.

[0003] In recent years, with the development of highly detailed exposure patterns, the use of extreme ultraviolet (EUV) light, with shorter wavelengths, as the light source for exposure is expanding, replacing deep ultraviolet (DUV) light. In exposure methods using EUV light, a photomask including a reflective layer that reflects the exposure light is used. To prevent foreign objects such as dust from adhering to the surface of the photomask, a protective film assembly is installed on the photomask.

[0004] Patent Document 1 discloses a protective film assembly. The protective film assembly disclosed in Patent Document 1 includes a specific protective film and a support frame supporting the protective film. The support frame has an opening. The protective film covers the opening of the support frame.

[0005] [Patent Document 1] International Publication No. 2018 / 008594 [Summary of the Invention]

[0006] [Problem to be solved by the invention] EUV light is easily absorbed by gases such as oxygen or nitrogen. Therefore, exposure using EUV light (hereinafter also referred to as "EUV exposure") is carried out in a vacuum environment.

[0007] At the start of EUV exposure, the entire exposure apparatus is evacuated. The protective film assembly disposed within the exposure apparatus is also exposed from atmospheric pressure to a vacuum environment. The evacuation speed of this exposure apparatus is fast. Specifically, even though vent holes are formed on the support frame to suppress the pressure difference between the inside and outside of the protective film assembly, the pressure drop rate outside the protective film assembly is faster than the pressure drop rate inside the protective film assembly. Therefore, as shown in FIG1, the protective film 510 is pressed from the inside of the protective film assembly 500 toward the outside of the protective film assembly 500. In FIG1, the arrow indicates the direction from the inside of the protective film assembly 500 to the outside of the protective film assembly 500, 530 represents the photomask, and H520 represents the opening.

[0008] On the other hand, after EUV exposure is completed, the entire exposure apparatus opens from a vacuum environment to an atmospheric pressure environment. At this time, the pressure outside the protective film assembly suddenly becomes higher than the pressure inside the protective film assembly. Therefore, the opposite phenomenon to that during vacuuming occurs in the protective film assembly. Specifically, as shown in FIG2, the protective film 510 is pressed from the outside of the protective film assembly 500 toward the inside of the protective film assembly 500. In FIG2, the arrow indicates the direction from the outside of the protective film assembly 500 toward the inside of the protective film assembly 500, 530 represents the photomask, and H520 represents the opening. If the protective film 510 is pressed toward the inside of the protective film assembly 500, as shown in FIG3A to FIG3C, stress tends to concentrate at the part of the protective film 510 facing the periphery P520 of the opening H520 of the support frame 520, which poses the problem that the protective film 510 is easily damaged.

[0009] This disclosure is made in view of the aforementioned circumstances. One embodiment of this disclosure aims to solve the problem of providing a protective film assembly, an exposure master, and an exposure apparatus that can suppress damage to the protective film caused by pressure differences inside and outside the protective film assembly. Another embodiment of this disclosure aims to solve the problem of providing a method for manufacturing a protective film assembly and a method for manufacturing a semiconductor device that can suppress damage to the protective film caused by pressure differences inside and outside the protective film assembly. [Means for Solving the Problem]

[0010] The means for solving the aforementioned problem includes the following embodiments. <1> A protective film assembly includes: a support frame having an opening; and a protective film covering the opening and supported by the support frame, the protective film having a self-supporting film region covering the opening, the self-supporting film region including an exposure region and a peripheral region surrounding the exposure region, the peripheral region having a thick film portion with a film thickness greater than that of the exposure region, satisfying (i) or (ii) below. (i) The support frame is a rectangular frame formed by a pair of long sides and a pair of short sides. The thick film portion is located at least in the peripheral region along a pair of long side regions formed by the long sides in the extending direction of the long sides. The pair of long side regions represent areas in the peripheral region between two locations on the extending direction from the center of the long sides toward one side and the other side, each at least 5% of the length of the opening representing the long side. (ii) The support frame is a square frame formed by a pair of first sides and a pair of second sides. The thick film portion is located at least in the peripheral region along a pair of first central regions formed by the first sides in a first extending direction and a pair of second central regions formed by the second sides in a second extending direction. The pair of first central regions represent areas in the peripheral region between two locations on the first extending direction from the center of the first sides toward one side and the other side, each at least 5% of the length of the opening representing the first side. The pair of second central regions represent areas in the peripheral region between two locations on the second extending direction, each at a distance of at least 5% of the length of the opening representing the second side portion from the central portion toward one side and the other side. <2> The protective film assembly as described in <1>, wherein (i) is satisfied. <3> The protective film assembly as described in <1>, wherein (ii) is satisfied. <4> The protective film assembly as described in any one of <1> to <3>, wherein the film thickness of the thick film portion is more than 1.5 times and less than 100 times the film thickness of the exposure area. <5> The protective film assembly as described in any one of <1> to <3>, wherein the protective film comprises carbon nanotubes. <6> The protective film assembly as described in any one of <1> to <3>, wherein the support frame is in contact with the protective film.<7> The protective film assembly as described in any one of <1> to <3>, wherein the protective film has: a first film portion without through holes; and a second film portion without a film portion in a region corresponding to the exposure area, the first film portion having a first carbon nanotube (CNT) layer comprising carbon nanotubes, the second film portion having a second CNT layer comprising carbon nanotubes, the total thickness of the first CNT layer and the second CNT layer in the thick film portion being at least 1.5 times and less than 100 times the thickness of the first CNT layer in the exposure area. <8> The protective film assembly as described in <7>, wherein the second film portion is deposited on the surface of the first film portion corresponding to the thick film portion, and the surface of the first film portion opposite to the support frame side. <9> An exposure master, comprising: a master; and a protective film assembly as described in any one of <1> to <8>, mounted on the master. <10> An exposure apparatus comprising: a light source for emitting exposure light; an exposure master as described in <9>; and an optical system for guiding the exposure light emitted from the light source to the exposure master, the exposure master being configured such that the exposure light emitted from the light source passes through the protective film and irradiates the master. <11> The exposure apparatus as described in <10>, wherein the exposure light is EUV light. <12> A method of manufacturing a protective film assembly, comprising the steps of: preparing the support frame; preparing the protective film; and connecting the support frame to the protective film. <13> The method of manufacturing a protective film assembly as described in <12>, wherein the protective film has carbon nanotubes, and in the step of preparing the protective film, the thick film portion is formed by spray coating or inkjet printing. <14> A method for manufacturing a protective film assembly, comprising: a step of preparing the support frame; a step of preparing a first film; a step of preparing a second film; a connecting step of connecting the support frame to a portion of one of the main surfaces of the first film; and a lamination step of laminating the second film onto the other main surface of the first film to form the protective film. <15> The method for manufacturing a protective film assembly as described in <14>, wherein each of the first film and the second film comprises carbon nanotubes. <16> The method for manufacturing a protective film assembly as described in <12>, wherein the protective film comprises a laminated film formed by laminating two or more CNT films comprising carbon nanotubes.<17> A method for manufacturing a semiconductor device, comprising: irradiating the original with exposure light emitted from a light source through the protective film of the original as described in <9>, and reflecting it through the original; and irradiating the sensing substrate with the exposure light reflected through the original through the protective film, thereby exposing the sensing substrate into a pattern.

[0011] <18> A protective film assembly, comprising: a support frame having an opening; and a protective film covering the opening and supported by the support frame, the protective film having a self-supporting film region covering the opening, the self-supporting film region including an exposure region and a peripheral region surrounding the exposure region, the peripheral region having a film thickness greater than the exposure region. <19> The protective film assembly of <18>, wherein the film thickness of the peripheral region is 1.5 times or more and 100 times or less than the film thickness of the exposure region. <20> The protective film assembly of <18> or <19>, wherein the film thickness of the exposure region is 2 nm or more and 40 nm or less. <21> The protective film assembly of any one of <18> to <20>, wherein the protective film comprises a carbon nanotube. <22> The protective film assembly of any one of <18> to <21>, wherein the support frame is in contact with the protective film. <23> A method for manufacturing a protective film assembly, comprising: a step of preparing the support frame; a step of preparing the protective film; and a connecting step of connecting the support frame to the protective film. <24> The method for manufacturing a protective film assembly as described in <23>, wherein the protective film has carbon nanotubes, and in the step of preparing the protective film, the thick film portion is formed by spray coating or inkjet printing. <25> A method for manufacturing a protective film assembly, comprising: a step of preparing the support frame; a step of preparing a first film; a step of preparing a second film; a connecting step of connecting the support frame to a portion of one of the main surfaces of the first film; and a lamination step of laminating the second film to the other main surface of the first film to form the protective film. <26> The method for manufacturing a protective film assembly as described in <25>, wherein each of the first film and the second film comprises carbon nanotubes. <27> A method for manufacturing a protective film assembly as described in any one of <23> to <26>, wherein the protective film comprises a laminated film formed by stacking two or more CNT films including carbon nanotubes. [Effects of the Invention]

[0012] According to one embodiment of the present disclosure, a protective film assembly, an exposure master, and an exposure apparatus can be provided, which can suppress damage to the protective film caused by the pressure difference between the inside and outside of the protective film assembly. According to another embodiment of the present disclosure, a method for manufacturing a protective film assembly and a method for manufacturing a semiconductor device can be provided, which can suppress damage to the protective film caused by the pressure difference between the inside and outside of the protective film assembly.

Implementation Method

[0014] In this disclosure, the numerical range represented by "~" refers to the range in which the values ​​recorded before and after "~" are respectively the minimum and maximum values. In the numerical ranges described in stages in this disclosure, the upper or lower limit value recorded in a certain numerical range can be replaced by the upper or lower limit value of other numerical ranges described in stages. In the numerical ranges described in this disclosure, the upper or lower limit value recorded in a certain numerical range can be replaced by the value shown in the embodiments. In this disclosure, a combination of two or more preferred states constitutes a better state. In this disclosure, when multiple substances equivalent to each component exist, unless otherwise specified, the amount of each component refers to the total amount of the multiple substances. In this specification, the term "step" not only includes independent steps, but also includes steps that cannot be clearly distinguished from other steps, as long as the desired purpose of the step is achieved.

[0015] The protective film assembly disclosed herein includes: a support frame having an opening; and a protective film covering the opening and supported by the support frame. The protective film has a self-supporting film region covering the opening. The self-supporting film region includes an exposure region and a peripheral region surrounding the exposure region. The peripheral region has a thicker film portion that is thicker than the exposure region. Satisfying either (i) or (ii) below. (i) The support frame is a rectangular frame formed by a pair of long sides and a pair of short sides. The thick film portion is located at least in the peripheral region along a pair of long side regions formed by the long sides in the extending direction of the long sides. The pair of long side regions represent areas in the peripheral region between two locations on the extending direction from the center of the long sides toward one side and the other side, each at least 5% of the length of the opening representing the long side. (ii) The support frame is a square frame formed by a pair of first sides and a pair of second sides. The thick film portion is located at least in the peripheral region along a pair of first central regions formed by the first sides in a first extending direction and a pair of second central regions formed by the second sides in a second extending direction. The pair of first central regions represent areas in the peripheral region between two locations on the first extending direction from the center of the first sides toward one side and the other side, each at least 5% of the length of the opening representing the first side. The pair of second central regions refer to the areas within the peripheral region between two locations along the second extension direction, extending from the central portion of the second side toward one side and the other side, at least 5% of the length of the opening representing the second side.

[0016] In this disclosure, the phrase "the thick film portion is located at least in a pair of long side regions formed along the long side portion in the extending direction of the long side portion" means that the thick film portion only needs to be located in a pair of long side regions. For example, in the case of a rectangular frame, the thick film portion may be located in the entire area of ​​the peripheral region, or in a pair of long side regions and a portion of the peripheral region other than the pair of long side regions. In this disclosure, the phrase "the thick film portion is located at least in a pair of first central regions formed along the first side portion in the first extending direction of the first side portion in the peripheral region, and a pair of second central regions formed along the second side portion in the second extending direction of the second side portion" means that the thick film portion only needs to be located in a pair of first central regions and a pair of second central regions. For example, in the case of a square frame, the thick film portion may be located in the entire area of ​​the peripheral region, or in a pair of first central regions and a pair of second central regions, or a portion of the peripheral region other than the pair of first central regions and a pair of second central regions. In this disclosure, the term "length in the opening of the long side" is the same as the length of the opening of the support frame in the extending direction. In this disclosure, the term "length in the opening of the first side" is the same as the length of the opening of the support frame in the first extending direction. In this disclosure, the term "length in the opening of the second side" is the same as the length of the opening of the support frame in the second extending direction.

[0017] The protective film assembly disclosed herein, by virtue of the aforementioned structure, can suppress the breakage of the protective film caused by the pressure difference between the inside and outside of the protective film assembly. In other words, compared with a protective film assembly with a uniform thickness of the protective film, it can suppress the breakage of the protective film caused by the pressure difference between the inside and outside of the protective film assembly. Previous protective film assemblies often had an adhesive layer between the support frame and the protective film, thus preventing direct contact between the protective film and the support frame and making it difficult for the protective film to break. However, protective film assemblies using films containing carbon nanotubes (hereinafter also referred to as "CNT films") often have a structure in which the support frame and the protective film are in direct contact without an adhesive layer. Compared with previous films containing polycrystalline silicon, CNT films are soft and prone to stress concentration caused by deformation. Based on the above, the problem of protective film breakage is more pronounced in protective film assemblies using CNT films. In particular, in protective films designed as previously described with a generally uniform film thickness, the aforementioned problem becomes even more apparent if the film thickness is reduced in order to improve the transmittance of the protective film.

[0018] Figure 4 shows the simulation results of the stress distribution of the protective membrane assembly observed from the top surface when the differential pressure to the protective membrane is set to 3 Pa (the differential pressure is applied in the direction that the protective membrane is pressed against the support frame) when the support frame is a rectangular frame. The shape of the protective membrane assembly frame is rectangular (length of a pair of short sides (longitudinal): 110 mm, length of a pair of long sides (horizontal): 143 mm). As shown in Figure 4, the stress on the protective membrane caused by the pressure difference inside and outside the protective membrane assembly is the greatest near the center of the pair of long sides of the support frame in the direction of extension of the long sides. In the protective membrane assembly disclosed herein, when the support frame is a rectangular frame, the thick film portion is located in the region of the pair of long sides. In this way, the protective membrane assembly disclosed herein can suppress the damage to the protective membrane caused by the pressure difference inside and outside the protective membrane assembly. In particular, by setting the thick film portion across the edge of the support frame in the direction from the peripheral region to the support frame, the damage to the protective membrane caused by stress concentration at the edge of the support frame can be easily suppressed.

[0019] Experiments show that when the support frame is a square frame, the stress on the protective film caused by the pressure difference between the inside and outside of the protective film assembly is greatest near the center of each of the four sides of the support frame. In the protective film assembly disclosed herein, when the support frame is a square frame, the thick film portion is located in a pair of first central regions and a pair of second central regions. Therefore, the protective film assembly disclosed herein can suppress damage to the protective film caused by the pressure difference between the inside and outside of the protective film assembly. In particular, by providing the thick film portion across the edge of the support frame from the peripheral region toward the support frame, damage to the protective film caused by stress concentration at the edge of the support frame can be easily suppressed.

[0020] The transmittance of EUV light is measured by a photodiode. Specifically, the transmittance of EUV light is expressed as the ratio of the current value detected with a protective film to the current value detected without a protective film.

[0021] The first and second embodiments of the protective film assembly, which are examples of the protective film assembly satisfying (i), will be described below with reference to FIGS. 5 to 10 and FIG. 12. The third embodiment of the protective film assembly, which is an example of the protective film assembly satisfying (ii), will be described below with reference to FIG. 13.

[0022] In the protective film assembly disclosed herein, it is preferable that the protective film assembly satisfies (i). Thereby, the transmittance of the exposed light can be increased by thinning the film thickness in the exposure area, while suppressing the damage to the protective film caused by the pressure difference between the inside and outside of the protective film assembly.

[0023] In the protective film assembly disclosed herein, it is preferable that the protective film assembly satisfies (ii). Thereby, the transmittance of the exposed light can be increased by thinning the film thickness in the exposure area, while suppressing the damage to the protective film caused by the pressure difference between the inside and outside of the protective film assembly.

[0024] In the protective film assembly disclosed herein, the thickness of the thick film portion is not particularly limited, but is preferably 1.5 times or more and 100 times or less the thickness of the film in the exposure area. This further suppresses damage to the protective film caused by pressure differences inside and outside the protective film assembly, and also results in excellent manufacturing costs.

[0025] In the protective film assembly disclosed herein, the protective film preferably comprises carbon nanotubes. This allows the protective film to be manufactured into a film with excellent mechanical strength. Therefore, the transmittance of the protective film for exposed light can be improved.

[0026] In the protective film assembly disclosed herein, it is preferable that the support frame is in contact with the protective film. Therefore, there is no adhesive between the protective film and the support frame. The escaping gas generally includes gases originating from water and gases originating from components contained in the adhesive. Therefore, the amount of escaping gas generated can be suppressed.

[0027] In the protective film assembly disclosed herein, preferably, the protective film has: a first film portion without through holes; and a second film portion without a film portion in the region corresponding to the exposure area, wherein the first film portion has a first CNT layer comprising carbon nanotubes, and the second film portion has a second CNT layer comprising carbon nanotubes, and the total thickness of the first CNT layer and the second CNT layer in the thick film portion is at least 1.5 times and less than 100 times the thickness of the first CNT layer in the exposure area. This further suppresses damage to the protective film caused by pressure differences inside and outside the protective film assembly.

[0028] In the protective film assembly disclosed herein, it is preferable that the second film portion is deposited on the surface of the first film portion corresponding to the thick film portion, and on the surface of the first film portion opposite to the support frame side. This way, even if a portion of the protective film separates at the end of the second film portion, generating fragments of carbon nanotubes, the falling of these fragments into the exposure original within the protective film assembly can be suppressed.

[0029] The exposure original disclosed herein includes the original and the protective film assembly of the present disclosure mounted on the original. The exposure originals of the first to third embodiments, which are examples of the exposure originals disclosed herein, will be described later.

[0030] The exposure apparatus disclosed herein includes: a light source that emits exposure light; an exposure template disclosed herein; and an optical system that guides the exposure light emitted from the light source to the exposure template. The exposure template is configured such that the exposure light emitted from the light source passes through the protective film and irradiates the template. The exposure templates of the first to third embodiments, which are examples of the exposure apparatus disclosed herein, will be described later.

[0031] In the exposure apparatus of the present invention, the exposure light is preferably EUV light.

[0032] The method for manufacturing the protective film assembly of the first state disclosed herein includes the following steps: preparing the support frame; preparing the protective film; and connecting the support frame to the protective film. This yields the protective film assembly of the present disclosure. Second, fourth, and sixth manufacturing methods, which are examples of the method for manufacturing the protective film assembly of the first state disclosed herein, will be described later.

[0033] In the method for manufacturing the protective film assembly disclosed herein, it is preferable that the protective film has carbon nanotubes, and in the step of preparing the protective film, the thick film portion is formed by spray coating or inkjet printing. This reduces manufacturing costs or allows selective thickening only of the thick film portion, facilitating easy mass production of the protective film assembly.

[0034] The method for manufacturing the second-state protective film assembly disclosed herein includes: a step of preparing the support frame; a step of preparing a first film; a step of preparing a second film; a connecting step of connecting the support frame to a portion of one of the main surfaces of the first film; and a lamination step of laminating the second film onto the other main surface of the first film to form the protective film. The protective film assembly disclosed herein is thus obtained. The first, third, and fifth manufacturing methods, which are examples of the method for manufacturing the second-state protective film assembly disclosed herein, will be described later.

[0035] In the method for manufacturing the protective film assembly disclosed herein, it is preferable that each of the first film and the second film comprises a carbon nanotube. This results in a protective film with good mechanical strength.

[0036] In the method for manufacturing the protective film assembly disclosed herein, it is preferable that the protective film comprises a laminated film consisting of two or more CNT films including carbon nanotubes. This results in a protective film with better mechanical strength.

[0037] The method for manufacturing a semiconductor device disclosed herein includes: a step of irradiating the original exposure plate with exposure light emitted from a light source through the protective film of the original exposure plate, and reflecting the light through the original exposure plate; and a step of irradiating the sensing substrate with the exposure light reflected through the original exposure plate through the protective film, thereby exposing the sensing substrate into a pattern. A semiconductor device is thus obtained. The manufacturing methods of the semiconductor device according to the first to third embodiments, which are examples of the method for manufacturing a semiconductor device disclosed herein, will be described later.

[0038] (1) First Embodiment (1.1) Protective Film Assembly Hereinafter, the protective film assembly 10A of the first embodiment of this disclosure will be described with reference to FIGS. 5 to 9B. The protective film assembly 10A satisfies (i). In detail, in the protective film assembly 10A, the support frame 12A is a rectangular frame, and the thick film portion TA is located in the entire area of ​​the peripheral region RA2. FIG. 5 is a top view showing the appearance of the protective film assembly 10A of the first embodiment of this disclosure. FIG. 6 is a cross-sectional view along line VI-VI of FIG. 5. In the figures, the same or equivalent parts are labeled with the same reference numerals and are not described repeatedly.

[0039] As shown in Figures 5 and 6, the protective film assembly 10A includes a protective film 11A and a support frame 12A (see Figure 6). The support frame 12A has an opening H12A (see Figure 6). The protective film 11A is supported by the support frame 12A. The protective film 11A is in contact with the support frame 12A. In the first embodiment disclosed herein, as shown in Figure 5, when viewed from above, the outline of the opening H12A of the support frame 12A is rectangular. "Viewed from above" means viewed in the thickness direction of the protective film 11A from the side of the protective film 11A where the support frame 12A is not located to the side of the protective film 11A where the support frame 12A is located. Furthermore, when viewed from above, the outline of the opening H12A of the support frame 12A is not particularly limited and may also be square.

[0040] The term "protective film in contact with the support frame" means that the protective film is attached to the support frame without passing through a resin adhesive layer. A layer used to bond the protective film to the support frame (e.g., a coating layer) may also exist between the protective film and the support frame. The material of the coating layer is not limited; for example, it can be an inorganic material, a metallic material, or a semiconductor material, and may also include Be, Ru, Ge, Pd, Si, Nb, Zr, and Mo.

[0041] Hereinafter, the direction extending from one side of the outline of the rectangular opening H12A when viewed from above will be defined as the left-right direction. The direction orthogonal to the left-right direction when viewed from above will be defined as the front-back direction. The thickness direction of the support frame 12A will be defined as the up-down direction. The side of the protective film 11A in the up-down direction where the support frame 12A is disposed will be defined as the lower side, and the opposite side will be defined as the upper side. Furthermore, in Figures 5 to 7, the right side corresponds to the positive X-axis direction, the left side corresponds to the negative X-axis direction, the front side corresponds to the positive Y-axis direction, the rear side corresponds to the negative Y-axis direction, the upper side corresponds to the positive Z-axis direction, and the lower side corresponds to the negative Z-axis direction.

[0042] (1.1.1) Protective Film (1.1.1.1) Self-supporting film region and supported region As shown in FIG5, the protective film 11A has a self-supporting film region RA and a supported region RB when viewed from above. The supported region RB surrounds the self-supporting film region RA when viewed from above. The self-supporting film region RA is adjacent to the supported region RB. The self-supporting film region RA represents the region covering the opening H12A of the support frame 12A. In detail, the self-supporting film region RA represents the region further inside than the first frame line B1 when viewed from above. The so-called "first frame line B1" refers to the line along the outline of the opening H12A of the support frame 12A when viewed from above. The details of the first frame line B1 will be described later with reference to FIG7. As shown in FIG6, the support frame 12A has a support surface S12 for supporting the protective film 11A. The self-supporting film region RA does not face the support surface S12 of the support frame 12A. The supported area RB represents the region in the protective film 11A that does not cover the opening H12A of the support frame 12A. Specifically, the supported area RB, viewed from above, represents the region outside the first frame line B1. The supported area RB includes the first frame line B1 (see Figure 5). As shown in Figure 6, the supported area RB faces the support surface S12 of the support frame 12A. The size of the self-supporting film region RA is appropriately selected based on the size of the pattern formed on the original. The length L1 (see Figure 5) of the self-supporting film region RA in the left-right direction (X-axis direction) can be, for example, set to 130 mm to 160 mm, preferably 135 mm to 147 mm, and more preferably 137 mm to 145 mm. The length L2 (see Figure 5) of the self-supporting film region RA in the up-down direction (Z-axis direction) can be, for example, 100 mm to 125 mm, preferably 110 mm to 116 mm, and more preferably 107 mm to 113 mm. The length L3 of the supported region RB in the left-right direction (X-axis direction) (refer to Figure 5) is greater than the length L1 of the self-supporting membrane region RA in the left-right direction (X-axis direction), and it is only necessary to ensure that the protective film 11A can be supported by the support frame 12A. The length L3 of the supported region RB in the left-right direction (X-axis direction) is, for example, 131 mm to 166 mm, preferably 136 mm to 153 mm, and more preferably 138 mm to 152 mm. The length L4 of the supported region RB in the vertical direction (Z-axis direction) (refer to Figure 5) is greater than the length L2 of the self-supporting membrane region RA in the vertical direction (Z-axis direction), and it is only necessary to ensure that the protective film 11A can be supported by the support frame 12A.

[0043] As shown in FIG. 5, the self-supporting film region RA, when viewed from above, includes an exposure region RA1 and a peripheral region RA2. The peripheral region RA2 surrounds the exposure region RA1. In the first embodiment disclosed herein, the exposure region RA1 and the peripheral region RA2 are adjacent. The exposure region RA1 represents the region through which EUV light passes during EUV exposure. The exposure region RA1 represents the region further inside than the second frame line B2 (see FIG. 5). Regarding the second frame line B2, it will be described later with reference to FIG. 7. The term "region through which EUV light passes" refers to the EUV light irradiation area required to expose the desired pattern on the sensing substrate described later. The EUV light irradiation area represents the region in the self-supporting film region RA that is pre-designed before EUV exposure. The peripheral region RA2 represents the region outside the second frame line B2. The peripheral region RA2 may also be a region through which EUV light does not pass during EUV exposure. The peripheral region RA2 includes the second frame line B2. The term "area that does not allow EUV light to pass through" refers to the area outside the EUV light irradiation zone in the self-supporting film region RA. EUV light scattered by the original material, etc., can also pass through this area that does not allow EUV light to pass through.

[0044] The first frame line B1 and the second frame line B2 will be described with reference to FIG7. FIG7 is a schematic top view of a microscope image of a portion of the periphery of the opening H12A taken from the protective film 11A of the protective film assembly 10A of the first embodiment disclosed herein. Specifically, FIG7 shows a schematic top view of a microscope image of the left side of the periphery of the opening H12A. The first frame line B1 and the second frame line B2 are determined by the following method. First, in a top view, one of the four sides of the periphery of the rectangular opening H12A is taken from the protective film 11A of the protective film assembly 10A. As shown in FIG7, the outline line P of the periphery of the opening H12A is extracted from the obtained microscope image of the protective film assembly 10A. When the outline line P of the opening H12A is clear, the outline line P usually has a concave-convex shape or a straight shape. A straight line B11 (hereinafter also referred to as "edge contour line B11") parallel to the front-back direction (Y-axis direction) is drawn, connecting to the most protruding part (i.e., the convex part) on the contour line P of the opening H12A. In the microscope image of the protective film assembly 10A, a line B12 (hereinafter also referred to as "edge contour line B12") parallel to the edge contour line B11 is drawn, connecting to the most concave part (i.e., the concave part) on the contour line P opposite to the opening H12A. The first frame line B1 is rectangular in shape, similar to the contour of the opening H12A, when viewed from above. The edge contour line B12 forms one side of the first frame line B1. A straight line B13 (hereinafter also referred to as "average edge contour line B13") is drawn at a position between the obtained edge contour lines B11 and B12 in the left-right direction (X-axis direction). The average edge contour line B13 is parallel to both edge contour lines B11 and B12. A straight line B21 (hereinafter also referred to as "reference line B21") is drawn 100 μm away from the average edge contour line B13 in the direction towards the exposure area RA1 (to the right (positive X-axis direction)). Reference line B21 is parallel to the average edge contour line B13. The second frame line B2 is located closer to the exposure area RA1 than the reference line B21. In other words, the second frame line B2 is more than 100 μm away from the average edge contour line B13 in the direction towards the exposure area RA1. The second frame line B2 is parallel to the reference line B21. The second frame line B2 is rectangular in shape, similar to the outline of the opening H12A, when viewed from above. One side of each of the first frame line B1 and the second frame line B2 is determined in this manner. The remaining three sides of the first frame line B1 and the second frame line B2 are determined in the same way. As described above, the first frame line B1 and the second frame line B2 are determined.

[0045] As a method for photographing a portion of the periphery of the opening H12A on the protective film 11A using a microscope, a laser microscope or an optical microscope is preferred. The magnification of the observation is not particularly limited, but is preferably in the range of 200x to 1000x. Specifically, a shape-resolving laser microscope (e.g., VK-100 from the VK series) manufactured by Keyence Corporation is used, with the objective lens magnification set to 20x, and the support frame 12A is positioned on the stage so that the contact surface of the protective film 11A is perpendicular to the incident light. The observation area includes the edge located inside the support frame 12A (i.e., the central portion side of the protective film assembly 10A shown in FIG. 5).

[0046] Furthermore, in the microscope image of the protective film assembly 10A, when the outline P of the opening H12A is unclear, an image showing the height profile of the support frame 12A is displayed. Using the contour line of the portion of the support frame 12A located approximately 10 μm below the protective film contact surface (uppermost part) as the outline line, the edge outline B11 and edge outline B12 are determined. The center line of edge outline B11 and edge outline B12 is defined as the average edge outline B13. The protective film contact surface (uppermost part) of the support frame 12A refers to the support surface S12.

[0047] Furthermore, the self-supporting film region RA may also include an intermediate region. The intermediate region may also be a region that prevents EUV light from passing through during EUV exposure. Viewed from above, the intermediate region is located between the exposure region RA1 and the peripheral region RA2. Specifically, the intermediate region surrounds the exposure region RA1. The intermediate region is surrounded by the peripheral region RA2. The intermediate region is adjacent to both the exposure region RA1 and the peripheral region RA2. The structure of the intermediate region may be the same as that of the exposure region RA1 or the peripheral region RA2.

[0048] The length L5 of the exposure area RA1 in the left-right direction (X-axis direction) (see Figure 5) is preferably 133 mm to 145 mm, more preferably 135 mm to 143 mm. The length L6 of the exposure area RA1 in the front-back direction (Y-axis direction) (see Figure 5) is preferably 105 mm to 115 mm, more preferably 106 mm to 113 mm.

[0049] (1.1.1.2) Thickness of the protective film The thickness of the peripheral region RA2 of the protective film 11A is greater than the thickness of the exposure region RA1. That is, the thick film portion TA is located in the entire area of ​​the peripheral region RA2 of the protective film 11A. As a result, the mechanical strength of the peripheral region RA2 is higher than that of the exposure region RA1. As a result, compared to a structure where the thickness of the peripheral region RA2 is the same as that of the exposure region RA1, the protective film 11A can suppress the breakage of the protective film 11A caused by the pressure difference inside and outside the protective film assembly 10A. By providing the thick film portion TA in a manner that crosses the first frame line B1 in the direction from the peripheral region RA2 to the supported region RB, the breakage of the protective film caused by stress concentration at the edge of the protective film assembly frame 12A towards the protective film 11A can be suppressed.

[0050] The film thickness of the peripheral region RA2 (i.e., the film thickness of the thick film portion TA) relative to the film thickness of the exposure region RA1 is preferably 1.5 times or more and 100 times or less. This allows for the thinning of the film thickness of the exposure region RA1 of the protective film 11A, thereby increasing the transmittance of the exposed light, while further suppressing damage to the protective film 11A caused by the pressure difference between the inside and outside of the protective film assembly 10A, and also results in excellent manufacturing costs. From the viewpoint of further suppressing damage to the protective film 11A caused by the pressure difference between the inside and outside of the protective film assembly 10A, the lower limit of the ratio of the film thickness of the peripheral region RA2 to the film thickness of the exposure region RA1 is preferably 1.9 times or more, more preferably 5 times or more, and particularly preferably 10 times or more. From the viewpoint of manufacturing costs, the upper limit of the ratio of the film thickness of the peripheral region RA2 to the film thickness of the exposure region RA1 is preferably 70 times or less, and more preferably 50 times or less.

[0051] The film thickness of the exposure region RA1 can be appropriately selected based on the material of the protective film 11A, and is preferably 2 nm or more and 40 nm or less. This suppresses degradation caused by damage to the protective film 11A and improves the transmittance of EUV light. From the viewpoint of further suppressing degradation caused by damage to the protective film 11A, the lower limit of the film thickness of the exposure region RA1 is preferably 6 nm or more, more preferably 8 nm or more, and particularly preferably 10 nm or more. From the viewpoint of further improving the transmittance of EUV light, the upper limit of the film thickness of the exposure region RA1 is preferably 30 nm or less, more preferably 20 nm or less, and particularly preferably 10 nm or less. The thinner the film thickness of the exposure region RA1, the more obvious the problem of the first embodiment of this disclosure becomes.

[0052] The film thickness of the peripheral region RA2 (i.e., the film thickness of the thick film portion TA) can be appropriately selected based on the film thickness of the exposure region RA1, and is preferably 5 nm or more and 500 nm or less. This reduces manufacturing costs and suppresses damage to the protective film 11A. From the viewpoint of further reducing manufacturing costs, the upper limit of the film thickness of the peripheral region RA2 is preferably 100 nm or less, and more preferably 50 nm or less. From the viewpoint of further suppressing damage to the protective film 11A, the lower limit of the film thickness of the peripheral region RA2 is preferably 10 nm or more, and more preferably 20 nm or more.

[0053] The film thickness of the supported region RB is not particularly limited, and may be the same as or different from the film thickness of the peripheral region RA2. However, from the viewpoint of ease of manufacturing, the film thickness of the supported region RB is preferably the same as the film thickness of the peripheral region RA2.

[0054] (1.1.1.2.1) Method for measuring film thickness: Referring to Figures 8A to 9B, the methods for measuring the film thickness of the exposure region RA1 and the film thickness of the peripheral region RA2 (i.e., the film thickness of the thick film portion TA) will be described. Figures 8A and 8B are explanatory diagrams for illustrating the method of transferring the self-supporting film region RA of the protective film 11A of the first embodiment of this disclosure onto the silicon substrate 20. Figure 9A is a top view of the silicon substrate on which the protective film 11A of the first embodiment of this disclosure is transferred, corresponding to the self-supporting film region 11X. Figure 9B is a cross-sectional view along line IXB-IXB of Figure 9A.

[0055] The film thickness of the exposure area RA1 and the film thickness of the peripheral area RA2 are obtained by transferring only the portion 11X (hereinafter also referred to as "self-supporting film portion 11X") corresponding to the self-supporting film area RA in the protective film 11A to the silicon substrate 20, and measuring the film thickness of a specific portion of the self-supporting film portion 11X using a film thickness measuring device.

[0056] Specifically, firstly, as shown in FIG8A, a solvent is dropped onto the silicon substrate 20 to form a solvent layer 21 on the silicon substrate 20. Then, the protective film 11A of the protective film assembly 10A is placed on the silicon substrate 20 with the protective film 11A facing the silicon substrate 20. The solvent layer 21 is provided between the silicon substrate 20 and the protective film 11A. The silicon substrate 20 only needs to be larger than the size of the self-supporting film area of ​​the protective film 11A; preferably, a silicon wafer of 4 inches or larger is used. Examples of solvents include water and organic solvents.

[0057] Next, by drying the solvent layer 21, the protective film 11A is made to adhere tightly to the silicon substrate 20 without gaps. Then, when the silicon substrate 20 is fixed and the support frame 12A of the protective film assembly 10A is lifted, as shown in FIG8B, the portion 11X of the protective film 11A corresponding to the self-supporting film region RA separates from the protective film 11A and remains on the silicon substrate 20. That is, the self-supporting film portion 11X is transferred to the silicon substrate 20. In a top view, the outline of the self-supporting film portion 11X follows the outline of the opening H12A of the support frame 12A. The portion 11Y of the protective film 11A corresponding to the supported region RB remains attached to the support frame 12A.

[0058] Next, as a film thickness measuring device, a microspectral film thickness gauge (e.g., OPTM, model: A-1, manufactured by Otsuka Electronics Co., Ltd.) is used to measure the film thickness at a specific measurement location on the self-supporting film portion 11X transferred to the silicon substrate 20. As a lens, for example, a reflective 10x lens is used, and as a device for adjusting the diameter of the measurement point, an aperture with a diameter of 200 μm (diameter of the measurement point: 20 μm) is used. An aluminum substrate is used as a reference for measuring the reflection intensity.

[0059] (1.1.1.2.2) Measurement Point In the first embodiment of this disclosure, the measured value of the film thickness at measurement point MP1 of the self-supporting film portion 11X is set as the film thickness of the exposure region RA1. As shown in FIG9A, measurement point MP1 represents a position 5 mm away from the edge P11X of the self-supporting film portion 11X toward the exposure region RA1. In the first embodiment of this disclosure, the measured value of the film thickness at measurement point MP2 of the self-supporting film portion 11X is set as the film thickness of the peripheral region RA2. As shown in FIG9A, measurement point MP2 is the position between the edge P11X of the self-supporting film portion 11X and a position 100 μm away from the edge P11X of the self-supporting film portion 11X toward the exposure region RA1.

[0060] (1.1.1.2.3) The method for converting to film thickness (optical thickness) is to obtain the reflectance spectrum in the wavelength range of 200 nm to 600 nm for each measurement point within a wavelength interval of 1 nm to 2 nm. Furthermore, when the protective film 11A is a film containing carbon nanotubes (hereinafter also referred to as "CNT film"), a three-layer model of air layer / CNT film layer / silicon substrate is used, and the reflectance spectrum in the wavelength range of 225 nm to 500 nm is analyzed using the least squares method, thereby calculating the film thickness at each measurement point.

[0061] The optical constants of the protective film 11A can be the optical constants corresponding to the material of the protective film 11A. When the protective film 11A includes graphite, the optical constants of graphite are used; when the protective film 11A includes a CNT film, the values ​​of the optical constants (refractive index: n, extinction coefficient: k) shown in Table 1 can be used.

[0062] [Table 1] [nm] n k 225 1.20 0.61 248 1.34 0.75 276 1.52 0.76 310 1.64 0.72 354 1.71 0.68 413 1.75 0.68 496 1.81 0.70

[0063] Furthermore, depending on the type of CNT, the optical constants of the CNT film may sometimes differ from those shown in Table 1. In cases where the optical constants of the CNT film differ from those shown in Table 1, the film thickness of the CNT film can also be measured using a contact-type film thickness gauge (hereinafter referred to as the "contact measurement method"). As a contact-type film thickness gauge, a stylus thickness measuring device (DEKTAK) or similar device can be used.

[0064] (1.1.1.2.4) When the method for measuring the film thickness of the protective film 11A is a contact-type measurement method, the film thickness of the protective film 11A can be measured as described below. The protective film 11A is transferred onto the silicon substrate 20 in the same manner as described in the [method for measuring the film thickness of the exposure area and the film thickness of the peripheral area]. A portion of the self-supporting film portion 11X is removed at a position 5 mm away from the edge P11X of the self-supporting film portion 11X toward the exposure area RA1 (a position within the exposure area RA1). This exposes the surface of the silicon substrate 20. The substrate surface height and the first film surface height are measured using a contact-type film thickness gauge. The term "substrate surface height" refers to the thickness of the silicon substrate 20 only. The term "first film surface height" refers to the total thickness of the silicon substrate 20 and the exposure area RA1 of the self-supporting film portion 11X. The thickness of the self-supporting film portion 11X in the exposure region RA1, i.e., the thickness of the protective film 11A in the exposure region RA1, is obtained based on the difference between the substrate surface height and the first film surface height. A portion of the self-supporting film portion 11X is removed at its edge P11X and at a position 100 μm away from the edge P11X towards the exposure region RA1 (within the peripheral region RA2). This exposes the surface of the silicon substrate 20. The substrate surface height and the second film surface height are measured using a contact thickness gauge. The "second film surface height" refers to the total thickness of the silicon substrate 20 and the peripheral region RA2 of the self-supporting film portion 11X. The thickness of the self-supporting film portion 11X in the peripheral region RA2, i.e., the thickness of the protective film 11A in the peripheral region RA2, is obtained based on the difference between the substrate surface height and the second film surface height.

[0065] Furthermore, when the optical constants of the CNT film are those shown in Table 1 and the film thickness of the self-supporting film region RA is 50 nm or less, the film thickness measurement method of the protective film 11A (CNT film) can also be a contact measurement method. In particular, when the film thickness of the self-supporting film region RA of the protective film 11A (CNT film) is 100 nm or more, if a microspectral film thickness gauge is used as the film thickness measurement device, the measurement error may increase. Therefore, when the film thickness of the self-supporting film region RA of the protective film 11A (CNT film) is 100 nm or more, a contact measurement method is preferred.

[0066] When the protective film 11A is not a CNT film, the method for measuring the film thickness of the protective film 11A can also be a contact-type measurement method.

[0067] (1.1.1.3) Structure of the Protective Film The structure of the protective film 11A is not particularly limited; it can be a single-layer structure or a laminated structure. From the viewpoint of ease of manufacturing the protective film 11A, a laminated structure is preferred. The laminated structure is, for example, a laminate of a first film portion (hereinafter also referred to as "unprocessed film") and a second film portion (hereinafter also referred to as "first processed film"). The unprocessed film is a flat film without through-holes. The first processed film is a flat film with through-holes. The through-holes penetrate the region corresponding to the exposure region. The periphery of the through-holes in the first processed film corresponds to the second frame line B2. That is, the first processed film does not have a film portion in the region corresponding to the exposure region RA1. Both the unprocessed film and the first processed film can be single-layer films or laminated films composed of multiple single-layer films. The materials of the multiple single-layer films can be the same or different. The first processed film can be located on the support frame 12A side of the protective film 11A, or it can be located on the side of the protective film 11A opposite to the support frame 12A side. From the viewpoint of preventing foreign matter from intruding into the opening H12A from the inner peripheral wall of the through hole of the first processed film, the first processed film is preferably deposited on the surface of the support frame 12A side of the unprocessed film. That is, the first processed film is preferably located on the side of the protective film 11A opposite to the support frame 12A side. In other words, it is preferable that the support frame 12A, the unprocessed film, and the first processed film are arranged sequentially from the lower direction (negative Z-axis direction) to the upper direction (positive Z-axis direction). Foreign matter intruding from the inner peripheral wall of the through hole of the first processed film includes fiber debris from the first processed film.

[0068] (1.1.1.4) Material of the Protective Film The material of the protective film 11A is not particularly limited, and examples include carbon-based materials, SiN, and polycrystalline silicon. Carbon-based materials include carbon nanotubes. When the protective film 11A is a laminated structure, the material of the unprocessed film and the material of the first processed film may be the same or different. In the first embodiment disclosed herein, the protective film 11A is in direct contact with the support frame 12A, but the protective film 11A may also be supported by the support frame 12A via a film adhesive layer. When the protective film 11A is supported by the support frame 12A via a film adhesive layer, the protective film 11A may also include an unprocessed film and an adhesive film. The adhesive film includes an adhesive that constitutes the film adhesive layer that permeates from the unprocessed film. The adhesive layer is formed in the region corresponding to the peripheral region RA2 on the unprocessed film. Examples of adhesives constituting the film adhesive layer may be the same as those exemplified as adhesives constituting the original adhesive layer described later. The protective film 11A is preferably made of carbon nanotubes. Because the protective film 11A is a CNT film, good mechanical strength can be obtained.

[0069] (1.1.1.4.1) The diameter of the tubes in the CNT film can be set to, for example, 0.8 nm or more and 400 nm or less. From the viewpoint of suppressing damage to the protective film 11A, the tube diameter is preferably 2 nm or more, more preferably 4 nm or more, even more preferably 8 nm or more, very preferably 10 nm or more, and especially preferably 20 nm or more. From the viewpoint of improving light transmittance, the tube diameter is preferably 100 nm or less, more preferably 80 nm or less, even more preferably 60 nm or less, and especially preferably 40 nm or less. Regarding the diameter of the tubes in the CNT, when they exist in the form of a single fiber in the protective film 11A, it refers to the diameter of the single fiber; when they exist in the form of a bundle of CNTs (i.e., a fiber bundle), it refers to the diameter of the fiber bundle.

[0070] CNTs are not particularly restricted and can be single-walled CNTs or multi-walled CNTs.

[0071] When the CNT is a single-walled CNT, the thickness of the fiber bundle in the single-walled CNT can be, for example, 4 nm or more and 400 nm or less. From the viewpoint of suppressing damage to the protective film 11A, the thickness of the fiber bundle is preferably 10 nm or more, more preferably 20 nm or more, further preferably 40 nm or more, and particularly preferably 50 nm or more. From the viewpoint of improving light transmittance, the thickness of the fiber bundle is preferably 100 nm or less, more preferably 80 nm or less, further preferably 60 nm or less, and particularly preferably 40 nm or less.

[0072] When the CNT is a multi-walled CNT, the thickness of the single fiber of the multi-walled CNT can be, for example, 4 nm or more and 400 nm or less. From the viewpoint of suppressing damage to the protective film 11A, the thickness of the fiber bundle is preferably 10 nm or more, more preferably 20 nm or more, further preferably 40 nm or more, and particularly preferably 50 nm or more. From the viewpoint of improving light transmittance, the thickness of the single fiber of the multi-walled CNT is preferably 100 nm or less, more preferably 80 nm or less, further preferably 60 nm or less, and particularly preferably 40 nm or less.

[0073] In the protective film 11A, it is preferable that the CNTs are formed into a non-woven fabric shape. The CNTs contained in the protective film 11A are usually fibrous in shape, so the protective film 11A as a whole can be formed into a non-woven fabric shape. By forming a non-woven fabric shape with the CNTs contained in the protective film 11A, the breathability of the protective film 11A can be ensured. For example, in the case of using an exposure apparatus including the protective film assembly 10A and exposing with EUV light, it is required to irradiate the protective film assembly 10A with EUV light under vacuum or reduced pressure conditions. As shown in FIG6, the protective film assembly 10A has a vent 121. The vent 121 is formed in the support frame 12A. Air inside the protective film assembly 10A is removed through the vent 121, thereby creating a vacuum or reduced pressure environment. However, there is a problem that forming the vent 121 on the support frame 12A is laborious. In the protective film 11A, the CNTs are formed into a non-woven fabric shape, and the breathability can be ensured by utilizing the non-woven fabric shape, thereby easily creating a vacuum or reduced pressure environment.

[0074] (1.1.1.4.2) Other layers may also be laminated in the protective film 11A. An antioxidant layer may also be laminated on at least one side of the protective film 11A. By including an antioxidant layer in the protective film assembly 10A, oxidation of the protective film 11A can be inhibited when exposed to light or when the protective film assembly is stored.

[0075] There are no particular restrictions on the material of the anti-oxidation layer, as long as it is a material that is stable to EUV light. For example, the material of the anti-oxidation layer can be SiOx (x≦2), SixNy (x / y is 0.7~1.5), SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, or Rh.

[0076] In order not to obstruct the transmission of EUV light, the thickness of the antioxidant layer is preferably about 1 nm to 10 nm, and more preferably about 2 nm to 5 nm. By setting the thickness of the antioxidant layer to about 1 nm to 10 nm, the absorption of EUV light by the antioxidant layer can be suppressed, thereby suppressing the decrease in the EUV light transmittance of the protective film 11A.

[0077] The ratio of the thickness of the antioxidant layer to the thickness of the protective film 11A is preferably in the range of 0.03 to 1.0. If the ratio of the thickness of the antioxidant layer to the thickness of the protective film 11A is within the aforementioned range, light absorption by the antioxidant layer can be suppressed, thereby suppressing the decrease in transmittance.

[0078] If an antioxidant layer is deposited on the protective film 11A, there is a risk that light reflection will occur at the newly formed layer interfaces, namely the interface between the antioxidant layer and the air, and the interface between the antioxidant layer and the protective film 11A, resulting in reduced transmittance. The light reflectance at these layer interfaces can be calculated based on the thickness of the protective film 11A and the antioxidant layer, as well as the types of elements constituting the protective film 11A and the antioxidant layer. Moreover, the reflectance can be reduced by optimizing the film thickness in the same way as with antireflective films.

[0079] Regarding the thickness of the antioxidant layer, it is preferable to set the thickness within the range that suppresses the decrease in light transmittance caused by absorption and the decrease in light transmittance caused by reflection, while having antioxidant properties.

[0080] There are no particular limitations on the thickness uniformity and surface roughness of the antioxidant layer. As long as the patterning step of exposure does not produce non-uniformity of transmittance caused by non-uniformity of film thickness or surface roughness, or obstacles caused by light scattering, the antioxidant layer can be either a continuous layer or an island-shaped layer, the film thickness can be non-uniform, and it can also have surface roughness.

[0081] The average refractive index of the film combining the protective film 11A and the antioxidant layer is preferably in the range of 1.9 to 5.0. The refractive index can be measured by methods such as spectroscopic elliptic polarization. The average density of the film combining the protective film 11A and the antioxidant layer is preferably in the range of 1.5 g / cm³ to 5.0 g / cm³. The density can be measured by methods such as X-ray reflectance analysis.

[0082] When the size of the self-supporting membrane region RA is 143 mm × 111 mm, the differential pressure that it can withstand is, for example, 10 Pa or more, preferably 20 Pa or more, more preferably 30 Pa or more, and even more preferably 50 Pa or more. The method for determining the differential pressure that the self-supporting membrane region RA can withstand when the size of the self-supporting membrane region RA is 143 mm × 111 mm is the same as the "damage evaluation based on expansion test" described in the examples.

[0083] When the protective film 11A includes a CNT film and other layers are present in the CNT film lamination, the thickness of the CNT film is preferably greater than the thickness of the other layers. When the protective film 11A includes a CNT film and other layers are present in the CNT film lamination, the outermost layer constituting the protective film 11A is preferably another layer. When the protective film 11A includes a CNT film and other layers are present in the CNT film lamination, as another example, the thickness of the CNT film is preferably 50% or more, and more preferably 70% or more, relative to the overall thickness of the protective film 11A including the other layers.

[0084] (1.1.1.5) The physical properties of the protective film, for example, when using EUV as the light during exposure, the energy of EUV is converted into heat through various relaxation processes. Therefore, it is preferable that the protective film 11A possesses both heat dissipation and heat resistance. By including CNTs, the protective film 11A can possess both heat dissipation and heat resistance, and there is less risk of damage to the protective film 11A during EUV lithography. Therefore, unlike the previous protective film 11A containing monocrystalline silicon, which has the problem of low heat dissipation and is prone to deformation or breakage due to heat damage during EUV light irradiation, the original can be reliably protected by using the protective film 11A. For details regarding the reasons why the protective film 11A containing CNTs possesses both heat dissipation and heat resistance, please refer to Japanese Patent Re-examination No. 2015 / 178250.

[0085] (1.1.2)The support frame is shown in Figure 5. The support frame 12A supports the protective film 11A.

[0086] The support frame 12A is a cylindrical object. The support frame 12A is a rectangular frame (i.e., a rectangular shape) formed by a pair of long sides 122 and a pair of short sides 123 when viewed from above. The support frame 12A has an opening H12A. The opening H12A is a through-hole for EUV exposure. During EUV exposure, EUV light passing through the exposure area RA1 of the protective film 11A passes through the opening H12A and reaches the original. The size of the opening H12A is approximately the same as the size of the first frame line B1 when viewed from above. The length L7 of the support frame 12A in the vertical direction (Z-axis direction) (see Figure 6) is, for example, approximately 2 mm.

[0087] As shown in Figure 6, the support frame 12A has a vent 121 for maintaining a constant air pressure within the EUV exposure apparatus in the space surrounded by the protective film assembly 10A and the original (not shown). Alternatively, the support frame 12A may not have a vent 121. Even if the support frame 12A does not have a vent 121, as long as the protective film 11A is non-woven, a vacuum environment and a depressurized environment can be created by the film's own permeability. Exposure using EUV light is performed in a vacuum environment (depressurized environment). Therefore, when depressurizing, the protective film 11A may sometimes expand or contract due to the pressure difference inside and outside the protective film assembly. In this case, the protective film 11A is at risk of breakage. Preferably, a filter is provided in the vent 121 in a manner that prevents foreign objects from entering the area surrounded by the protective film assembly and the original. Examples of filters include ultra-low penetration air (ULPA) filters and metal screens. The support frame 12A can also be colored within a range that does not obstruct exposure, making it easy to inspect.

[0088] Regarding the material and shape of the support frame 12A, there are no particular restrictions as long as it is a frame capable of supporting the protective film 11A. The material of the support frame 12A may include aluminum, titanium, stainless steel, ceramic-based materials (such as silicon, glass, etc.), and resins such as polyethylene. From the viewpoint of minimizing water content and suppressing the generation of escaping gas, the material of the support frame 12A is preferably aluminum, titanium, stainless steel, silicon, or glass, and more preferably aluminum, titanium, or silicon.

[0089] The support frame 12A may also include a first support frame supporting the protective film 11A and a second support frame connected to the first support frame. When the support frame 12A includes both a first support frame and a second support frame, the first and second support frames may be bonded together via a support frame adhesive layer. The adhesives constituting the support frame adhesive layer may be the same as those exemplified as constituting the original adhesive layer 13 described later. For example, in this disclosure, a protective film assembly 10A including a support frame having a structure for connecting a second support frame to a first support frame may be manufactured collaboratively by a manufacturer of a plurality of first support frames supporting the protective film 11A and a manufacturer connecting the second support frame to the first support frame. The protective film assembly 10A also includes a structure comprising a protective film 11A and a first support frame in a phase prior to being bonded to the second support frame.

[0090] There are no particular limitations on the procedure and method for fixing the protective film 11A to the support frame. An etched substrate can also be used as part of the support frame 12A. For example, the protective film 11A can be deposited on a substrate such as metal, silicon substrate, glass, resin, or salt that can be removed by a specific processing method. Then, depending on the size of the frame, a mask can be applied to the substrate surface opposite to the surface where the protective film 11A is disposed, and the remaining mask shape can be etched or dissolved. This yields a protective film assembly 10A that uses a portion of the substrate as a support frame.

[0091] There are no particular limitations on the trimming method used to make the shape of the substrate conform to the shape of the frame. When using a silicon substrate, a mechanical wafer cutting method or a laser trimming method can be used.

[0092] (1.1.3) As shown in FIG6, the protective film assembly 10A of the first embodiment disclosed herein includes a substrate adhesive layer 13. The substrate adhesive layer 13 contains adhesive. Alternatively, the protective film assembly 10A may not include the substrate adhesive layer 13.

[0093] (1.1.3.1) There are no particular limitations on the adhesive contained in the adhesive layer 13 for the original adhesive. For example, adhesives may include: acrylic resin adhesives, epoxy resin adhesives, polyimide resin adhesives, silicone resin adhesives, inorganic adhesives, double-sided adhesive tapes, polyolefin adhesives, hydrogenated styrene adhesives, etc. From the viewpoint of ease of coating and hardening processes, the adhesive is preferably selected from at least one of the group consisting of silicone resin adhesives, acrylic resin adhesives, hydrogenated styrene adhesives, and epoxy resin adhesives. In this disclosure, the concept of adhesive includes not only adhesives but also binders. When the adhesive is applied along the entire circumference of the protective film assembly 10A, the thickness of the adhesive layer 13 for the original adhesive can be 1 μm or more and 1 mm or less, preferably 5 μm to 500 μm, and more preferably 10 μm to 200 μm.

[0094] (1.1.4) Application of the protective film assembly The protective film assembly 10A can be used not only as a protective component in the EUV exposure apparatus to prevent foreign matter from adhering to the original plate, but also as a protective component to protect the original plate during storage or transportation. For example, if it is pre-configured to have the protective film assembly installed on the original plate (exposing the original plate), it can be stored directly after being removed from the EUV exposure apparatus. Methods for installing the protective film assembly on the original plate include methods such as adhesive application, electrostatic adsorption, and mechanical fixing.

[0095] The protective film assembly 10A is preferably used for exposure using short-wavelength exposure light (e.g., EUV light, light with a wavelength shorter than EUV light, etc.). Of the above, the protective film 11A is preferably used for exposure using EUV light.

[0096] In this disclosure, "EUV (Extreme Ultra Violet) light" refers to light with a wavelength of 1 nm or more and 30 nm or less. Preferably, the wavelength of EUV light is 5 nm or more and 13.5 nm or less. In this disclosure, EUV light and light with wavelengths shorter than EUV light are collectively referred to as "EUV light".

[0097] (1.1.5) Modification Example: As a modification of the protective film assembly 10A, the protective film 11A forming the protective film assembly 10A may have an anti-oxidation layer on both surface layers of the film. If an anti-oxidation layer is deposited on the protective film 11A, oxidation of the protective film 11A can be suppressed during EUV light irradiation or storage of the protective film assembly. Furthermore, the anti-oxidation layer may also be deposited only on one side of the protective film 11A.

[0098] As shown in FIG. 10, the protective film 11A may also have a first film portion 11A1 and a second film portion 11A2. The first film portion 11A1 does not have a through hole. The second film portion 11A2 does not have a film portion in the region corresponding to the exposure region RA1. The second film portion 11A2 is deposited on the surface of the first film portion 11A1 opposite to the support frame 12A side in the region corresponding to the thick film portion TA of the first film portion 11A1 (i.e., the peripheral region RA2). The first film portion 11A1 has a first CNT layer 1111 containing carbon nanotubes and a coating layer 1112. The coating layer 1112 is formed on the two main surfaces of the first CNT layer 1111. The second film portion 11A2 has a second CNT layer 1113 containing carbon nanotubes and a coating layer 1114. The coating layer 1114 is formed on the two main surfaces of the second CNT layer 1113. The total thickness of the first CNT layer 1111 and the second CNT layer 1113 in the thick film portion TA (i.e., the peripheral region RA2) is 1.5 times to 100 times the thickness of the first CNT layer 1111 in the exposure region RA1. This allows for a reduction in the film thickness of the protective film 11A in the exposure region RA1, thereby increasing the transmittance of the exposed light, while further suppressing damage to the protective film 11A caused by the pressure difference between the inside and outside of the protective film assembly 10A. Examples of materials for coating layers 1112 and 1114 include B, B4C, ZrN, Mo, Ru, SiC, TiN, and aC.

[0099] (1.2) The original exposure version of the first embodiment disclosed herein includes an original plate and a protective film assembly 10A installed on the original plate. The original exposure version of the first embodiment disclosed herein includes a protective film assembly 10A, and therefore performs the same effect as the protective film assembly 10A.

[0100] In the first embodiment disclosed herein, the method of mounting the original plate to the protective film assembly 10A (hereinafter also referred to as the "mounting method") involves fixing the original plate to the support frame 12A via an adhesive layer 13 for the original plate located on one end face of the support frame 12A. The mounting method is not limited to the method of fixing the original plate to the support frame 12A via the adhesive layer 13 for the original plate. For example, the mounting method may involve directly attaching the original plate to the support frame 12A, or it may involve fixing the original plate to the support frame 12A using a mechanical fixing method or the attraction of a magnet or the like.

[0101] The original image has a supporting substrate, a reflective layer, and an absorber layer. The reflective layer is deposited on the supporting substrate. The absorber is formed on the reflective layer. In this case, a protective film assembly 10A is mounted on the side of the original image where the reflective layer and the absorber layer are provided. By absorbing a portion of the light (e.g., EUV light) through the absorber layer, the desired image is formed on the sensing substrate (e.g., a semiconductor substrate with a photoresist film). The reflective layer may be a multilayer film of molybdenum (Mo) and silicon (Si). The absorber layer may be a material with high absorption of EUV light, such as chromium (Cr) or tantalum nitride.

[0102] (1.3) Exposure Apparatus The exposure apparatus of the first embodiment of this disclosure includes a light source, an exposure plate of the first embodiment of this disclosure, and an optical system. The light source emits exposure light. The optical system guides the exposure light emitted from the light source to the exposure plate. The exposure plate is arranged such that the exposure light emitted from the light source passes through the protective film 11A and irradiates the plate. Therefore, the exposure apparatus of the first embodiment of this disclosure performs the same effect as the exposure plate of the first embodiment of this disclosure.

[0103] The exposure apparatus of the first embodiment of this disclosure includes: a light source that emits exposure light; an exposure template of the first embodiment of this disclosure; and an optical system that guides the exposure light emitted from the light source to the exposure template, wherein the exposure template is configured such that the exposure light emitted from the light source passes through the protective film and irradiates the template. According to this configuration, in addition to forming finer patterns (e.g., linewidths of 32 nm or less) using EUV light, even when using EUV light where resolution defects caused by foreign objects are a problem, pattern exposure with reduced resolution defects caused by foreign objects can be performed.

[0104] In the first embodiment of this disclosure, the exposure light is preferably EUV light.

[0105] (1.4) Method for manufacturing protective film assembly Hereinafter, the method for manufacturing protective film assembly according to the first embodiment of the present disclosure will be described.

[0106] As a method for manufacturing the protective film assembly according to the first embodiment of this disclosure, a first manufacturing method and a second manufacturing method can be listed. Hereinafter, the first manufacturing method and the second manufacturing method will be described in sequence.

[0107] (1.4.1) First Manufacturing Method The first manufacturing method disclosed herein is a method for manufacturing a protective film assembly 10A, comprising: a step of preparing a support frame 12A (hereinafter also referred to as the "first support frame preparation step"); a step of preparing a first film (hereinafter also referred to as the "first film preparation step"); a step of preparing a second film (hereinafter also referred to as the "second film preparation step"); a first connecting step of connecting the support frame 12A to a portion of one of the main surfaces of the first film; and a lamination step of laminating a second film to at least a region corresponding to the peripheral region RA2 (i.e., the thick film portion TA) on the other main surface of the first film to form a protective film 11A.

[0108] One of the first film and the second film has a through hole (hereinafter also referred to as "through hole") that penetrates the region corresponding to the exposure region RA1.

[0109] In the first manufacturing method, one of the first film and the second film has a through hole, thus obtaining a protective film assembly 10A in which the thickness of the peripheral region RA2 (i.e., the thick film portion TA) is greater than the thickness of the film in the exposure region RA1. That is, according to the first manufacturing method, a protective film assembly 10A is obtained that can suppress the breakage of the protective film 11A caused by the pressure difference inside and outside the protective film assembly 10A.

[0110] The lamination step and the first connection step are performed after the first support frame preparation step, the first membrane preparation step, and the second membrane preparation step. There is no particular limitation on the execution order of the first support frame preparation step, the first membrane preparation step, and the second membrane preparation step. There is also no particular limitation on the execution order of the lamination step and the first connection step.

[0111] The second membrane preferably has through holes. This provides a protective membrane assembly 10A, which sequentially comprises a support frame 12A, a first membrane without through holes, and a second membrane with through holes. Therefore, foreign matter caused by the through holes can be prevented from entering the opening H12A. Foreign matter caused by the through holes includes fiber debris from the protective film 11A.

[0112] Hereinafter, the case in which the second membrane has through holes and the first connection step and the lamination step are performed in sequence will be described.

[0113] (1.4.1.1)First film preparation step In the first film preparation step, a first film is prepared. There is no particular limitation on the method of preparing the first film. For example, the first film can also be formed on the substrate.

[0114] The first membrane may also contain CNTs. The following explains the case where the first membrane contains CNTs.

[0115] The first membrane preparation step may also include a step of preparing CNTs (hereinafter also referred to as the "CNT preparation step") and a step of forming CNTs into sheets to manufacture the first membrane (hereinafter also referred to as the "CNT membrane manufacturing step"). The CNT preparation step and the CNT membrane manufacturing step are performed sequentially.

[0116] In the CNT preparation steps, prepare the CNTs. CNTs can be obtained from commercially available products or manufactured.

[0117] Preferably, the CNT is formed on a chemical vapor deposition substrate using a CVD (Chemical Vapor Deposition) method, in which a metal catalyst is present in the reaction system and an oxidant is added in the reaction atmosphere. CVD methods include plasma CVD, low-pressure CVD, or thermal CVD. In this case, water vapor can be used as the oxidant. The concentration of water vapor can be 10 ppm or more and 10,000 ppm or less, and water vapor can be added at a temperature of 600°C or more and 1000°C or less.

[0118] CNTs can be synthesized by placing a metal catalyst on a chemical vapor deposition substrate or by patterning it. The resulting CNTs can be single-layered or multi-layered, and can be CNTs erected in a direction perpendicular to the surface of the chemical vapor deposition substrate. For example, CNTs can be manufactured with reference to International Publication No. 2006 / 011655. As commercially available products of this type of CNT, examples include CNTs manufactured using the super-growth method sold by Zeon Corporation of Japan.

[0119] As a CNT (or CNT bulk structure), it is preferable to use those manufactured by a modified direct injection pyrolytic synthesis method (enhanced direct injection pyrolytic synthesis) (hereinafter also referred to as "e-DIPS method"). Direct injection pyrolytic synthesis (hereinafter also referred to as "DIPS method") is a gas-phase flow method. Specifically, in the DIPS method, a hydrocarbon solution containing a catalyst (or catalyst precursor) and a reaction promoter is atomized by a sprayer and introduced into a high-temperature heating furnace, thereby synthesizing monolayer CNTs in a flowing gas phase. The e-DIPS method is a gas-phase flow method modified from the DIPS method. Specifically, the "e-DIPS method" focuses on the formation process of ferrocene used in the catalyst with different particle sizes on the upstream and downstream sides of the reactor. Unlike the DIPS method, which only uses an organic solvent as a carbon source, it is easier to decompose into the carrier gas. This method involves controlling the growth point of monolayer CNTs by mixing a second carbon source that can easily serve as a carbon source. For details, please refer to Saito et al., "J. Nanoscience and Nanotechnology", 8 (2008) 6153-6157. As a commercially available product of this type of CNT, one example is "MEIJO eDIPS" manufactured by Meijo Nano Carbon Co., Ltd.

[0120] In the CNT film manufacturing step, CNTs are formed into sheets to manufacture the first film.

[0121] CNTs (or bulk CNT structures) obtained using methods such as CVD and e-DIPS can be used in a state of dispersion in a solvent. A liquid (dispersion) containing dispersed CNTs (or bulk CNT structures) is coated onto a substrate, and the solvent is evaporated and removed, thereby forming a CNT film on the substrate. In the first embodiment disclosed herein, by removing the solvent used in the dispersion, a film in which the CNTs are substantially parallel to the surface of the substrate can be obtained. The coating method is not particularly limited; for example, spin coating, dip coating, rod coating, spray coating, electrospray coating, etc., can be used. Furthermore, the metal catalyst used in CNT formation can sometimes cause a decrease in EUV transmittance, but since the CNTs are almost entirely free of metal catalyst when peeled off from a chemical vapor deposition substrate, this has no effect.

[0122] Inorganic materials can be used as the substrate. For example, silicon (Si) can be used as the substrate. Furthermore, the substrate is not limited to silicon (Si), and can be semiconductor materials such as germanium (Ge), silicon-germanium (SiGe), silicon carbide (SiC), and gallium arsenide (GaAs), or glass substrates such as quartz glass substrate (silicon oxide (SiO2)), sodium glass substrate, borosilicate glass substrate, and sapphire substrate, as well as silicon nitride (SiN) substrate, aluminum nitride (AlN) substrate, zirconium oxide (ZrO2) substrate, and aluminum oxide (Al2O3) substrate. From the viewpoint of reducing thermal strain with the CNT film, the substrate is preferably any one of silicon, sapphire, or silicon carbide, whose coefficient of linear thermal expansion is close to that of the first film. Silicon (Si) can be any of monocrystalline silicon, polycrystalline silicon, microcrystalline silicon, and amorphous silicon, but monocrystalline silicon is preferred from the perspectives of etching efficiency, versatility, and low cost. The shape of the substrate is not particularly limited and can be circular or rectangular. The thickness of the substrate is not particularly limited, but is preferably 100 μm or more and 1000 μm or less; from an operational perspective, it is preferably 200 μm or more and 1000 μm or less.

[0123] Alternatively, a CNT film can be formed on the filter paper by removing the solvent by dropping a dispersion of CNTs onto the filter paper.

[0124] (1.4.1.2)Second film preparation step In the second film preparation step, a second film is prepared. There is no particular limitation on the method of preparing the second film. For example, the second film may also be formed on the substrate.

[0125] The second membrane may also contain CNTs. If the second membrane contains CNTs, the preparation steps for the second membrane may be the same as those for the first membrane.

[0126] The second film preparation step includes the step of forming through holes on the second film. The method for forming through holes on the second film is not particularly limited. For example, the following methods can be listed: mechanically rubbing the first film, chemical etching, laser ablation, applying a mask on the substrate on which the first film is formed and forming through holes during the film formation process, and forming a film by spray coating or inkjet printing in the manner of forming through holes.

[0127] Each of the first and second films preferably contains CNTs, and more preferably is composed of CNTs. By making each of the first and second films composed of CNTs, the obtained protective film 11A can be made into a film with excellent mechanical strength, which can improve the transmittance of the exposed light of the protective film.

[0128] (1.4.1.3)First Support Frame Preparation Step In the first support frame preparation step, support frame 12A is prepared. The prepared support frame 12A has an opening H12A. The method for preparing support frame 12A is any known method.

[0129] (1.4.1.4) First Connection Step In the first connection step, a support frame 12A is connected to a portion of one of the main surfaces of the first film. Specifically, in the first connection step, the first film is connected to the support frame 12A in such a way that it covers the opening H12A of the support frame 12A having the opening H12A. In the first connection step, the separated first film may also be connected to the support frame 12A (i.e., the protective film assembly frame) after the first film has been separated from the substrate.

[0130] There is no particular limitation on the method of separating the first film from the substrate, and the following manufacturing examples can be cited as examples.

[0131] (1.4.1.4.1) A sacrificial layer is deposited on a substrate using a sacrificial layer method, and a first film is formed on the sacrificial layer. The sacrificial layer is then removed, thereby obtaining a self-supporting film. The sacrificial layer may be a metal, oxide film, resin, salt, or other material that can be removed by a specific processing method. For example, the sacrificial layer may be a metal such as aluminum that dissolves in an acidic solution. Specifically, a metal layer is deposited on the surface of a glass substrate or silicon substrate by evaporation, sputtering, or similar methods. After depositing the first film on the metal layer, the substrate is immersed in a solution such as an acidic solution that can dissolve the metal layer, thereby allowing the first film to be peeled off from the substrate.

[0132] When using a silicon substrate with a natural oxide film or silicon oxide layer as the substrate, after applying the first film to the natural oxide film or silicon oxide layer on the silicon substrate, it is immersed in a hydrofluoric acid aqueous solution, thereby removing the natural oxide film or silicon oxide layer and peeling the first film off from the substrate.

[0133] The material of the sacrificial layer deposited on the substrate may also be a partially saponified polyvinyl alcohol resin or a water-soluble material such as sodium chloride. A first film is deposited on the sacrificial layer to obtain a laminate, and the obtained laminate is immersed in water, thereby allowing the first film to be peeled off from the substrate.

[0134] When selecting a method for removing the sacrificial layer deposited on the substrate, the most appropriate method can be selected based on the characteristics of the first film, such as process resistance, film strength, removal speed of the sacrificial layer, uniformity of film thickness of the sacrificial layer, or surface roughness.

[0135] (1.4.1.4.2)Etching or dissolving of the substrate: When the substrate material is set to metal, oxide film, resin, salt, etc., which can be removed by a specific processing method, the substrate is etched or dissolved after the first film is deposited on the substrate, thereby obtaining the film.

[0136] For example, when using copper foil as a substrate, after applying a first film to the surface of the copper foil, the substrate is immersed in a copper chloride etching solution to etch the copper foil substrate and remove the substrate, thereby obtaining the first film.

[0137] When the substrate is a glass substrate, after the first film is deposited on the glass substrate, hydrofluoric acid can be used to etch the glass substrate to remove the substrate, thereby obtaining the first film.

[0138] When the substrate is a silicon substrate, after the first film is deposited on the silicon substrate, the silicon substrate can be removed by etching it using wet etching or dry etching to obtain the first film. Wet etching can use etching solutions such as KOH, tetramethyl ammonium hydroxide (TMAH), or hydrazine. Dry etching can use etching gases such as fluorine-based (SF6, CF4, NF3, PF5, BF3, CHF3, XeF2, F2+NO), chlorine-based (Cl2, SiCl4), or bromine-based (IBr). The wet etching rate varies with temperature; therefore, in order to etch without damaging the first film containing CNTs on the silicon substrate, it is preferable to lower the liquid temperature to reduce the etching rate.

[0139] When dry etching a silicon substrate, an etching stop layer or similar layer may be pre-formed on the surface of the silicon substrate. Examples of etching stop layers include layers containing SiO2 or SiN. Preferably, the etching stop layer includes a film that generates tensile stress. Residual stresses acting in a direction parallel to the surfaces of the substrate and the film include tensile stress and compressive stress. Tensile stress occurs when a force within the film is applied to expand it, while compressive stress occurs when a force within the film is applied to contract it. These stresses are primarily generated during the film-forming process. One factor contributing to residual stress is the difference in the coefficients of thermal expansion between the substrate and the film. Upon returning to room temperature, both the substrate and the film shrink, but the proportion varies depending on the coefficient of thermal expansion. If the coefficient of thermal expansion of the film is greater than that of the substrate, tensile stress occurs; conversely, compressive stress occurs. It is preferable to apply tension to a first film disposed on the film using a film that generates tensile stress, thus forming a wrinkle-free first film. Because the SiN-containing layer generates tensile stress, the first film obtained by dry etching the silicon substrate can be a wrinkle-free film. After the dry etching of the silicon substrate is completed, the etch stop layer is removed, thereby obtaining the self-supporting film as desired.

[0140] When the substrate is a substrate containing salts such as sodium chloride, after the first film is deposited on the surface of the substrate, the substrate can be removed by etching it in water to obtain the first film. When the substrate is a plastic substrate, after the first film is deposited on the surface of the plastic substrate, it can be immersed in a solvent that can dissolve the plastic substrate to dissolve the plastic substrate and obtain the first film.

[0141] (1.4.1.4.3) Surface treatment controls the interaction between the first film and the substrate surface by performing surface treatment on the substrate, thereby allowing the first film to be easily peeled off from the substrate by immersion in a solvent or mechanical peeling process. For example, surface treatment methods using silane coupling agents can be used to control the interaction between the first film and the substrate surface. Other methods include cleaning the substrate surface using water, organic solvents, piranha solution, sulfuric acid, ultraviolet (UV) ozone treatment, etc. When the substrate is a silicon substrate, solutions used in RCA cleaning methods, such as a mixture of hydrogen peroxide and ammonium hydroxide, or a mixture of hydrochloric acid and hydrogen peroxide, can be used.

[0142] The deposition of the sacrificial layer and the surface treatment on the substrate can be combined using methods for etching or dissolving the substrate. Preferably, the substance used for the deposition of the sacrificial layer or the surface treatment is difficult to remain on the surface and interior of the first film, and even if the substance remains on the surface and interior of the first film, it can be easily removed by means of readily available methods. Examples include etching using gas, evaporation using heat, cleaning using a solvent, and removal by photolysis; these methods can also be combined for removal.

[0143] (1.4.1.5) Lamination Step In the lamination step, a second film is laminated on at least the region corresponding to the peripheral region on the other main surface of the first film to form a protective film 11A. In the lamination step, the second film may also be laminated onto the first film after the second film is separated from the substrate.

[0144] There is no particular limitation on the method for separating the second film from the substrate, and the same method as the method exemplified as the method for separating the first film from the substrate can be listed.

[0145] There is no particular limitation on the method of depositing the separated second membrane onto the first membrane. For example, methods such as using a support frame 12A connected to the first membrane to retrieve the second membrane floating on the surface of the water, forming the second membrane on the first membrane by spray coating or inkjet coating and then depositing it are examples.

[0146] The protective film 11A is preferably a laminated film comprising two or more CNT films including carbon nanotubes. This results in a protective film with better mechanical strength. The number of carbon nanotube films constituting the laminated film need only be two or more, preferably two to 30, and more preferably three to ten. Examples of carbon nanotube films include sheet-like CNTs as a first film and CNT-containing films as a second film.

[0147] (1.4.1.6) Adhesive Layer Forming Step In the first embodiment disclosed herein, the method for manufacturing the protective film assembly 10A includes an adhesive layer forming step. By performing the adhesive layer forming step, a master film such as a photomask can be bonded to the support frame 12A via the master film adhesive layer 13. In the adhesive layer forming step, adhesive is applied to the surface of the opening of the support frame 12A that is opposite to the side for which the protective film 11A is connected. Alternatively, a partition can be arranged in such a way that it contacts the surface of the formed master film adhesive layer 13 that is opposite to the support frame 12A. In this way, the adhesiveness of the master film adhesive layer 13 can be maintained while storing the protective film assembly 10A until the master film is bonded to the support frame 12A via the master film adhesive layer 13. Furthermore, the method for manufacturing the protective film assembly 10A may also omit the adhesive layer forming step.

[0148] (1.4.2) Second manufacturing method The second manufacturing method disclosed herein is a method for manufacturing a protective film assembly 10A, comprising: a step of preparing a support frame 12A (hereinafter also referred to as the "second support frame preparation step"); a step of preparing a protective film 11A (hereinafter also referred to as the "protective film preparation step"); and a second connection step of connecting the support frame 12A to the protective film 11A.

[0149] According to the second manufacturing method disclosed herein, a protective film assembly 10A is obtained, which can suppress the damage to the protective film 11A caused by the pressure difference inside and outside the protective film assembly 10A.

[0150] The second connection step is performed after the second support frame preparation step and the protective film preparation step are performed. There is no particular limitation on the execution order of the second support frame preparation step and the protective film preparation step.

[0151] (1.4.2.1) Protective Film Preparation Step In the protective film preparation step, a protective film 11A is prepared. The protective film preparation step may be a step of preparing only a pre-manufactured protective film 11A, or it may be a step of manufacturing the protective film 11A. If the protective film preparation step is a step of manufacturing the protective film 11A, the method for preparing the protective film 11A is appropriately selected according to the type of protective film 11A. The method for preparing the protective film 11A may also include the first film preparation step and the second film preparation step.

[0152] Preferably, the protective film 11A has carbon nanotubes, and the thick film portion TA (i.e., the peripheral region RA2) is formed by spray coating or inkjet printing. Spray coating or inkjet printing is any known method.

[0153] (1.4.2.2)Second support frame preparation steps The second support frame preparation steps are performed in the same way as the first support frame preparation steps.

[0154] (1.4.2.3) Second Connection Step In the second connection step, the protective film 11A is connected to the support frame 12A. Specifically, in the second connection step, the protective film 11A is connected to the support frame 12A in such a way that it covers the opening H12A of the support frame 12A. In the second connection step, for example, the separated protective film 11A may also be connected to the support frame 12A after the protective film 11A has been separated from the substrate. The method for separating the protective film 11A from the substrate is the same as the method exemplified for separating the first film from the substrate. The method for connecting the separated protective film 11A to the support frame 12A is not particularly limited; for example, a method of using the support frame 12A to retrieve the protective film 11A floating on the surface of water can be cited.

[0155] (1.5) Semiconductor Device Manufacturing Method The semiconductor device manufacturing method of the first embodiment disclosed herein includes a reflection step and an exposure step. In the reflection step, exposure light emitted from a light source is passed through a protective film 11A of an exposure substrate and irradiated onto the substrate, whereby the substrate reflects the light. In the exposure step, the exposure light reflected by the substrate is passed through the protective film 11A and irradiated onto a sensing substrate, thereby exposing the sensing substrate into a pattern. The reflection step and the exposure step are performed sequentially. According to the semiconductor device manufacturing method of the first embodiment disclosed herein, even when using EUV light where resolution defects caused by foreign matter are easily problematic, a semiconductor device with reduced resolution defects caused by foreign matter can be obtained.

[0156] Hereinafter, an example of a method for manufacturing a semiconductor device according to the first embodiment of the present disclosure will be described with reference to FIG11. FIG11 is a schematic cross-sectional view of an EUV exposure apparatus 800, which is an exposure apparatus according to the first embodiment of the present disclosure. As shown in FIG11, the EUV exposure apparatus 800 includes: a light source 831 that emits EUV light; an exposure template 850, which is an example of an exposure template of the present disclosure; and an illumination optical system 837 that guides the EUV light emitted from the light source 831 to the exposure template 850. The exposure template 850 includes a protective film assembly 10A and a template 833, wherein the protective film assembly 10A includes a protective film 11A and a support frame 12A. The exposure template 850 is configured such that the EUV light emitted from the light source 831 passes through the protective film 11A and irradiates the template 833. The template 833 reflects the irradiated EUV light into a pattern.

[0157] In the EUV exposure apparatus 800, filter windows 820 and 825 are respectively provided between the light source 831 and the illumination optical system 837, and between the illumination optical system 837 and the original plate 833. The EUV exposure apparatus 800 includes a projection optical system 838 that guides the EUV light reflected by the original plate 833 toward the sensing substrate 834.

[0158] In the EUV exposure apparatus 800, EUV light reflected from the original 833 is guided onto the sensing substrate 834 through the projection optics system 838, and the sensing substrate 834 is exposed to form a pattern. Furthermore, the EUV exposure is performed under reduced pressure conditions.

[0159] The EUV light source 831 emits EUV light toward the illumination optical system 837. The EUV light source 831 includes a target material and a pulsed laser irradiation unit. By irradiating the target material with a pulsed laser to generate plasma, EUV can be obtained. If the target material is Sn, EUV with a wavelength of 13 nm to 14 nm can be obtained. The wavelength of the light emitted by the EUV light source is not limited to 13 nm to 14 nm, as long as it is light with a wavelength in the range of 5 nm to 30 nm that is suitable for the purpose.

[0160] The illumination optical system 837 focuses the light irradiated by the EUV light source 831 and homogenizes the illuminance to illuminate the original plate 833. The illumination optical system 837 includes a multilayer film reflector 832 for adjusting the EUV light path and an optical coupler (optical integrator), etc. The multilayer film reflector is a multilayer film with alternating layers of molybdenum (Mo) and silicon (Si).

[0161] There are no particular limitations on the installation method of the filter windows 820 and 825. Examples include mounting them using an adhesive or mechanically fixing them within the EUV exposure apparatus. The filter window 820, positioned between the light source 831 and the illumination optical system 837, captures stray particles (debris) generated by the light source to prevent them from adhering to components inside the illumination optical system 837 (e.g., the multilayer mirror 832). On the other hand, the filter window 825, positioned between the illumination optical system 837 and the original plate 833, captures stray particles (debris) from the light source 831 side to prevent them from adhering to the original plate 833.

[0162] Foreign matter adhering to the original wafer can absorb or scatter EUV light, thus causing poor resolution of the wafer. Therefore, the protective film assembly 10A is installed to cover the EUV light irradiation area of ​​the original wafer 833. EUV light is irradiated onto the original wafer 833 through the protective film 11A.

[0163] EUV light reflected by the original plate 833 passes through the protective film 11A and is projected onto the sensing substrate 834 via the projection optical system 838. The projection optical system 838 focuses the light reflected by the original plate 833 onto the sensing substrate 834. The projection optical system 838 includes multiple multilayer film reflectors 835 and 836 for adjusting the EUV light path.

[0164] The sensing substrate 834 is a substrate formed by coating a photoresist onto a semiconductor wafer, and the photoresist is cured in a patterned manner using EUV reflected by the original substrate 833. The photoresist is developed and the semiconductor wafer is etched, thereby forming the desired pattern on the semiconductor wafer.

[0165] The protective film assembly 10A is mounted on the original substrate 833 via the original substrate adhesive layer 13, etc. Foreign matter adhering to the original substrate may absorb or scatter EUV, thus causing poor resolution of the wafer. Therefore, the protective film assembly 10A is mounted in such a way that it covers the EUV light irradiation area of ​​the original substrate 833, and EUV light is irradiated onto the original substrate 833 through the protective film 11A.

[0166] As for the method of mounting the protective film assembly 10A onto the original plate 833, any method that can be set on the original plate in a way that prevents foreign matter from adhering to the surface of the original plate is acceptable. Examples include methods such as attaching the support frame 12A to the original plate 833 using adhesive, electrostatic adsorption, or mechanical fixing, but there are no particular limitations. It is preferable to use a method of mounting using adhesive.

[0167] As a manufacturing method disclosed herein, a method for laminating a first film and a second film is disclosed, but in addition to these films, other films may also be further laminated.

[0168] (2)Second Embodiment (2.1) Protective Film Assembly Hereinafter, the protective film assembly 10B of the second embodiment of this disclosure will be described with reference to FIG12. The protective film assembly 10B satisfies the above (i). FIG12 is a top view showing the appearance of the protective film assembly 10B of the second embodiment of this disclosure.

[0169] The protective film assembly 10B is otherwise identical to the protective film assembly 10A of the first embodiment, except that the thick film portion exists only along the central portion of each of the two long sides of the support frame. As shown in FIG12, the protective film assembly 10B includes a protective film 11B and a support frame 12A. The support frame 12A has an opening H12A. The protective film 11B is supported by the support frame 12A. The protective film 11B is in contact with the support frame 12A. In the second embodiment disclosed herein, as shown in FIG12, when viewed from above, the outline of the opening H12A of the support frame 12A is rectangular.

[0170] Hereinafter, the direction extending from one side of the outline of the rectangular opening H12A when viewed from above will be defined as the left-right direction. The direction orthogonal to the left-right direction when viewed from above will be defined as the front-back direction. The thickness direction of the support frame 12A will be defined as the up-down direction. The side of the protective film 11B in the up-down direction where the support frame 12A is disposed will be defined as the lower side, and the opposite side will be defined as the upper side. Furthermore, in FIG12, the right side corresponds to the positive X-axis direction, the left side corresponds to the negative X-axis direction, the front side corresponds to the positive Y-axis direction, the rear side corresponds to the negative Y-axis direction, the upper side corresponds to the positive Z-axis direction, and the lower side corresponds to the negative Z-axis direction.

[0171] (2.1.1)The protective film 11B differs from the protective film 11A of the first embodiment in that the thick film portion TB is not formed in the entire area of ​​the peripheral region RA2.

[0172] (2.1.1.1)The self-supporting membrane region and the supported region are shown in Figure 12. When viewed from above, the protective film 11B has a self-supporting membrane region RA and a supported region RB.

[0173] As shown in FIG12, the self-supporting film region RA includes an exposure region RA1 and a peripheral region RA2 when viewed from above. In the protective film 11B, the peripheral region RA2 surrounds the exposure region RA1. In the second embodiment disclosed herein, the exposure region RA1 and the peripheral region RA2 are adjacent to each other.

[0174] The peripheral region RA2 has a pair of long side regions RA21. The support frame 12A is a rectangular frame formed by a pair of long side portions 122 and a pair of short side portions 123. The pair of long side regions RA21 are formed along the long side portion 122 in the extension direction (X-axis direction) of the long side portion 122.

[0175] A pair of long side regions RA21 represent the areas in the peripheral region RA2 that, in the extending direction (X-axis direction), are located between two points E1 and E2, on one side (positive X-axis direction) and the other side (negative X-axis direction), respectively, at least 5% of the length L1 (see Figure 12) in the opening H12A of the long side portion 122.

[0176] From the viewpoint that the distance L8 is 5% or more relative to the length L1 in the opening H12A of the long side portion 122, it is more preferably 7% or more and 49% or less, and more preferably 10% or more and 45% or less, in order to suppress the damage to the protective film 11B caused by the pressure difference inside and outside the protective film assembly 10B.

[0177] The distance from L8 is preferably 7 mm to 70 mm, and more preferably 15 mm to 65 mm.

[0178] (2.1.1.2) Thickness of the protective film The thickness of the pair of long side regions RA21 of the protective film 11B (i.e., the thickness of the thick film portion TB) is greater than the thickness of the exposure region RA1. Therefore, the mechanical strength of the pair of long side regions RA21 is higher than that of the exposure region RA1. As shown in FIG4, the stress on the protective film caused by the pressure difference between the inside and outside of the protective film assembly tends to increase in the pair of long side regions RA21 of the protective film 11B. As a result, compared to a structure where the thickness of the pair of long side regions RA21 is the same as that of the exposure region RA1, the protective film 11B can suppress damage to the protective film 11B caused by the pressure difference between the inside and outside of the protective film assembly 10B. In particular, by providing the thick film portion across the edge of the support frame 12A from the peripheral region RA2 toward the outer edge of the support frame 12A, damage to the protective film 11B caused by stress concentration at the edge of the support frame 12A can be easily suppressed.

[0179] The film thickness of each of the pair of long-side regions RA21 (i.e., the film thickness of the thick film portion TB) relative to the film thickness of the exposure region RA1 is preferably 1.5 times or more and 100 times or less. This further suppresses damage to the protective film 11B caused by the pressure difference between the inside and outside of the protective film assembly 10B, and also improves manufacturing cost. From the viewpoint of further suppressing damage to the protective film 11B caused by the pressure difference between the inside and outside of the protective film assembly 10B, the lower limit of the ratio of the film thickness of the pair of long-side regions RA21 to the film thickness of the exposure region RA1 is preferably 1.9 times or more, more preferably 5 times or more, and particularly preferably 10 times or more. From the viewpoint of manufacturing cost, the upper limit of the ratio of the film thickness of the pair of long-side regions RA21 to the film thickness of the exposure region RA1 is preferably 70 times or less, and more preferably 50 times or less.

[0180] The thick film portion TB may be located at least in a pair of long side regions RA21, or it may be located in a region different from the pair of long side regions RA21, in addition to the pair of long side regions RA21. As a region different from the pair of long side regions RA21, a pair of short side regions may be cited. The pair of short side regions are formed along the short side portion 123 in the extending direction (Y-axis direction) of the short side portion 123. The pair of short side regions refer to the regions in the peripheral region RA2 that are located between two points in the extending direction (Y-axis direction) of the short side portion 123, extending from the center of the short side portion 123 toward one side (positive Y-axis direction) and the other side (negative Y-axis direction), respectively, at least 5% of the length L2 in the opening H12A of the short side portion 123.

[0181] (2.1.1.3)Method for measuring film thickness The method for measuring the film thickness of the exposure area RA1 and the film thickness of the pair of long side areas RA21 is the same as the method for measuring the film thickness of the exposure area RA1 and the peripheral area RA2 of the protective film 11A.

[0182] (2.1.1.4) Structure of the Protective Film The structure of the protective film 11B is not particularly limited; it can be a single-layer structure or a laminated structure. From the viewpoint of ease of manufacturing the protective film 11B, a laminated structure is preferred. The laminated structure is, for example, a laminate of a first film portion (hereinafter also referred to as "unprocessed film") and a pair of third film portions (hereinafter also referred to as "a pair of second-processed films"). The pair of second-processed films are flat films including regions corresponding to a pair of long-side regions RA21 (a pair of thick film portions TB). That is, the second-processed films do not have film portions in the region corresponding to the exposure region RA1. Each of the unprocessed film and the pair of second-processed films can be a single-layer film or a laminated film composed of multiple single-layer films. The materials of the multiple single-layer films can be the same or different. The pair of second processed films can be located on the support frame 12A side of the protective film 11B, or on the opposite side of the protective film 11B from the support frame 12A side. From the viewpoint of preventing foreign matter from intruding into the opening H12A from the inner peripheral wall of the through-hole of the second processed film, the pair of second processed films is preferably deposited on the surface of the unprocessed film on the support frame 12A side. That is, the pair of second processed films is preferably located on the opposite side of the protective film 11B from the support frame 12A side. In other words, it is preferable that the support frame 12A, the unprocessed film, and the pair of second processed films are arranged sequentially from the lower direction (negative Z-axis direction) to the upper direction (positive Z-axis direction). Foreign matter intruding from the pair of second processed films includes fiber debris from the pair of second processed films.

[0183] (2.1.1.5) Material of the Protective Film The material of the protective film 11B is not particularly limited, and materials exemplified as those used for the protective film 11A can be listed. When the protective film 11B is a laminated structure, the material of the unprocessed film and the material of the pair of second processed films can be the same or different. Preferably, the material of the protective film 11B includes carbon nanotubes. By using a CNT film, good mechanical strength can be obtained.

[0184] (2.1.1.5.1) Other layers may also be laminated on the protective film 11B. An antioxidant layer may also be laminated on at least one side of the protective film 11B. Examples of antioxidant layers are the same as those exemplified as antioxidant layers that can be laminated on the protective film 11A.

[0185] When the protective film 11B includes a CNT film and other layers are laminated with the CNT film, the thickness of the CNT film is preferably greater than the thickness of the other layers. When the protective film 11B includes a CNT film and other layers are laminated with the CNT film, the outermost layer constituting the protective film 11B is preferably another layer. When the protective film 11B includes a CNT film and other layers are laminated with the CNT film, as another example, the thickness of the CNT film is preferably 50% or more, and more preferably 70% or more, relative to the overall thickness of the protective film 11B including the other layers.

[0186] (2.1.1.6)Properties of the protective film The protective film 11B preferably has the same properties as those exemplified as those of the protective film 11A.

[0187] (2.1.2) The modified protective film 11B may also have a first film portion and a second film portion. The first film portion does not have a through hole. The second film portion does not have a film portion in the region corresponding to the exposure region RA1. The second film portion is deposited on the surface of the first film portion opposite to the side of the support frame 12A, in the region corresponding to the thick film portion TB of the first film portion (i.e., a pair of long side regions RA21). The first film portion is the same as the first film portion 11A1 (see FIG. 10) of the modified example of the first embodiment. The second film portion is the same as the second film portion 11A2 (see FIG. 10) of the modified example of the first embodiment, except that the second film portion is deposited in the region corresponding to the thick film portion TB of the first film portion (i.e., a pair of long side regions RA21).

[0188] (2.2) The exposure original of the second embodiment disclosed herein includes an original and a protective film assembly 10B installed on the original. The exposure original of the second embodiment of this disclosure includes the protective film assembly 10B, and therefore performs the same effect as the protective film assembly 10B. The exposure original of the second embodiment of this disclosure is the same as the exposure original of the first embodiment of this disclosure except that the protective film assembly 10B is used instead of the protective film assembly 10A.

[0189] (2.3) Exposure Apparatus The exposure apparatus of the second embodiment of this disclosure includes a light source, an exposure plate of the second embodiment of this disclosure, and an optical system. The light source emits exposure light. The optical system guides the exposure light emitted from the light source to the exposure plate. The exposure plate is arranged such that the exposure light emitted from the light source passes through the protective film 11B and irradiates the plate. Therefore, the exposure apparatus of the second embodiment of this disclosure performs the same effect as the exposure plate of the second embodiment of this disclosure. The exposure apparatus of the second embodiment of this disclosure is the same as the exposure apparatus of the first embodiment, except that it uses the exposure plate of the second embodiment of this disclosure instead of the exposure plate of the first embodiment of this disclosure.

[0190] (2.4) Method for manufacturing the protective film assembly As a method for manufacturing the protective film assembly according to the second embodiment of this disclosure, a third manufacturing method and a fourth manufacturing method may be listed. Hereinafter, the third manufacturing method and the fourth manufacturing method will be described in turn.

[0191] (2.4.1)Third Manufacturing Method The third manufacturing method disclosed herein is a method for manufacturing a protective film assembly 10B, comprising: a step of preparing a support frame 12A; a step of preparing a first film; a step of preparing a second film; a first connecting step of connecting the support frame 12A to a portion of one of the main surfaces of the first film; and a lamination step of laminating the second film to at least a region on the other main surface of the first film corresponding to a pair of long side regions RA21 (i.e., thick film portion TB) to form a protective film 11B.

[0192] According to the third manufacturing method, a protective film assembly 10B is obtained, which can suppress the damage of the protective film 11B caused by the pressure difference inside and outside the protective film assembly 10B.

[0193] The third manufacturing method disclosed herein is the same as the first manufacturing method disclosed herein, except that a second regionally laminated film corresponding to at least a pair of long-side regions RA21 (i.e., thick film portion TB) is deposited on the other main surface of the first film instead of a second regionally laminated film corresponding to at least a peripheral region RA2 (i.e., thick film portion TA) on the other main surface of the first film.

[0194] (2.4.2)Fourth Manufacturing Method The fourth manufacturing method disclosed herein is a method for manufacturing a protective film assembly 10B, comprising: a step of preparing a support frame 12A; a step of preparing a protective film 11B; and a second connection step of connecting the support frame 12A to the protective film 11B.

[0195] According to the fourth manufacturing method disclosed herein, a protective film assembly 10B is obtained, which can suppress the damage to the protective film 11B caused by the pressure difference inside and outside the protective film assembly 10B.

[0196] The fourth manufacturing method disclosed herein is the same as the second manufacturing method disclosed herein, except that the protective film 11B is prepared instead of the protective film 11A.

[0197] There is no particular limitation on the method for preparing the protective film 11B. For example, the protective film 11B may have carbon nanotubes, and the thick film portion TB (i.e., a pair of long side regions RA21) may be formed by spray coating or inkjet printing. Spray coating or inkjet printing is acceptable as long as it is a known method.

[0198] (2.5) Semiconductor Device Manufacturing Method The semiconductor device manufacturing method of the second embodiment disclosed herein includes a reflection step and an exposure step. In the reflection step, exposure light emitted from a light source is passed through a protective film 11B of the exposure film to irradiate the film, and is reflected by the film. In the exposure step, the exposure light reflected by the film is passed through the protective film 11B to irradiate a sensing substrate, thereby exposing the sensing substrate into a pattern. The reflection step and the exposure step are performed sequentially. According to the semiconductor device manufacturing method of the second embodiment disclosed herein, even when using EUV light where resolution defects caused by foreign matter are easily problematic, a semiconductor device with reduced resolution defects caused by foreign matter can be obtained.

[0199] The method for manufacturing a semiconductor device according to the second embodiment of this disclosure is the same as the method for manufacturing a semiconductor device according to the first embodiment of this disclosure, except that a protective film 11B is used instead of a protective film 11A.

[0200] (3)Third Embodiment (3.1) Protective Film Assembly Hereinafter, the protective film assembly 10C of the third embodiment of this disclosure will be described with reference to FIG13. The protective film assembly 10C satisfies the above (ii). FIG13 is a top view showing the appearance of the protective film assembly 10C of the third embodiment of this disclosure.

[0201] The protective film assembly 10C is mainly the same as the protective film assembly 10A of the first embodiment, except that the support frame is square and the thick film portion exists along the center of each of the four sides of the support frame. As shown in FIG13, the protective film assembly 10C includes a protective film 11C and a support frame 12C. The support frame 12C has an opening H12C. The protective film 11C is supported by the support frame 12C. The protective film 11C is in contact with the support frame 12C. In the third embodiment disclosed herein, as shown in FIG13, when viewed from above, the outline of the opening H12C of the support frame 12C is square.

[0202] Hereinafter, the direction in which a pair of parallel first sides extend in the outline of the square opening H12C when viewed from above is defined as the left-right direction. The direction in which a pair of parallel second sides extend in the outline of the square opening H12C when viewed from above is defined as the front-back direction. The thickness direction of the support frame 12C is defined as the up-down direction. The side of the protective film 11C in the up-down direction where the support frame 12C is disposed is defined as the lower side, and the opposite side is defined as the upper side. Furthermore, in FIG13, the right side corresponds to the positive X-axis direction, the left side corresponds to the negative X-axis direction, the front side corresponds to the positive Y-axis direction, the rear side corresponds to the negative Y-axis direction, the upper side corresponds to the positive Z-axis direction, and the lower side corresponds to the negative Z-axis direction.

[0203] (3.1.1)The protective film 11C differs from the protective film 11A of the first embodiment in that the thick film portion TC is not formed in the entire area of ​​the peripheral region RA2.

[0204] (3.1.1.1)The self-supporting membrane region and the supported region are shown in Figure 13. When viewed from above, the protective film 11C has a self-supporting membrane region RA and a supported region RB.

[0205] As shown in FIG13, the self-supporting film region RA includes an exposure region RA1 and a peripheral region RA2 when viewed from above. In the protective film 11C, the peripheral region RA2 surrounds the exposure region RA1. In the third embodiment disclosed herein, the exposure region RA1 and the peripheral region RA2 are adjacent to each other.

[0206] The peripheral region RA2 has a pair of first central regions RA22 and a pair of second central regions RA23. The support frame 12C is a square-shaped frame formed by a pair of first sides 124 and a pair of second sides 125. The pair of first central regions RA22 are formed along the first side 124 in a first extending direction (X-axis direction) extending from the first side 124. The pair of second central regions RA23 are formed along the second side 125 in a second extending direction (Y-axis direction) extending from the second side 125.

[0207] A pair of first central regions RA22 represent the regions in the peripheral regions RA2 between two locations E3, E4 in the first extending direction (X-axis direction), from the central portion 1240 of the first side portion 124 toward one side and the other side, respectively, at least 5% of the length L1 (see Figure 13) of the opening H12C in the first side portion 124.

[0208] A pair of second central regions RA23 represent the regions in the peripheral region RA2 between two locations E5 and E6 on the second extending direction (Y-axis direction), from the central portion 1250 of the second side portion 125 toward one side and the other side, respectively, at least 5% of the length L1 (see Figure 13) of the opening H12C in the second side portion 125.

[0209] From the viewpoint of suppressing damage to the protective film 11C caused by the pressure difference inside and outside the protective film assembly 10C, a distance L9 of 5% or more relative to the length L1 of the opening H12C in the first side portion 124 or the length L1 of the opening H12C in the second side portion 125 is preferably 7% or more and 50% or less, and more preferably 10% or more and 45% or less.

[0210] (3.1.1.2) Film Thickness of the Protective Film The peripheral region RA2 of the protective film 11C has four thick film portions TC that are thicker than the exposure region RA1. In the third embodiment, each of the four thick film portions TC is located in a pair of first central regions RA22 and a pair of second central regions RA23 in the peripheral region RA2. Thereby, the mechanical strength of each pair of first central regions RA22 and the pair of second central regions RA23 is higher than that of the exposure region RA1. In the third embodiment, the stress on the protective film caused by the pressure difference inside and outside the protective film assembly tends to increase in the pair of first central regions RA22 and the pair of second central regions RA23. As a result, compared to a structure where the film thickness of the pair of first central regions RA22 and the pair of second central regions RA23 is the same as the film thickness of the exposure region RA1, the protective film 11C can suppress the damage of the protective film 11C caused by the pressure difference inside and outside the protective film assembly 10C. In particular, by providing a thick film portion TC that extends from the peripheral region RA2 toward the outer edge of the support frame 12C and across the edge of the support frame 12C, damage to the protective film 11C caused by stress concentration at the edge of the support frame 12C to the protective film 11C can be easily suppressed.

[0211] The film thickness (i.e., the film thickness of the thick film portion TC) of each of the pair of first central regions RA22 and the pair of second central regions RA23 is preferably 1.5 times or more and 100 times or less relative to the film thickness of the exposure region RA1. This further suppresses damage to the protective film 11C caused by the pressure difference between the inside and outside of the protective film assembly 10C, and also improves manufacturing cost. From the viewpoint of further suppressing damage to the protective film 11C caused by the pressure difference between the inside and outside of the protective film assembly 10C, the lower limit of the ratio of the film thickness of each of the pair of first central regions RA22 and the pair of second central regions RA23 to the film thickness of the exposure region RA1 is preferably 1.9 times or more, more preferably 5 times or more, and particularly preferably 10 times or more. From the viewpoint of manufacturing cost, the upper limit of the ratio of the film thickness of each of the pair of first central regions RA22 and the pair of second central regions RA23 to the film thickness of the exposure region RA1 is preferably 70 times or less, and more preferably 50 times or less.

[0212] The thick film portion TC only needs to be located in at least a pair of first central regions RA22 and a pair of second central regions RA23. It can be located only in a pair of first central regions RA22 and a pair of second central regions RA23, or it can be located in a region different from the pair of first central regions RA22 and a pair of second central regions RA23, in addition to the pair of first central regions RA22 and a pair of second central regions RA23.

[0213] (3.1.1.3)Method for measuring film thickness The method for measuring the film thickness of the exposure area RA1 and the film thickness of the pair of first central areas RA22 and the pair of second central areas RA23 is the same as the method for measuring the film thickness of the exposure area RA1 and the film thickness of the peripheral area RA2 of the protective film 11A.

[0214] (3.1.1.4) Structure of the Protective Film The structure of the protective film 11C is not particularly limited; it can be a single-layer structure or a laminated structure. From the viewpoint of ease of manufacturing the protective film 11C, a laminated structure is preferred. The laminated structure is, for example, a laminate of a first film portion (hereinafter also referred to as "unprocessed film") and four fourth film portions (hereinafter also referred to as "four third-processed films"). The four third-processed films are flat films including regions corresponding to a pair of first central regions RA22 and a pair of second central regions RA23. Each of the unprocessed film and the four third-processed films can be a single-layer film or a laminated film composed of multiple single-layer films. The materials of the multiple single-layer films can be the same or different. The four third-processed films can be on the support frame 12C side of the protective film 11C or on the side opposite to the support frame 12C side of the protective film 11C. From the viewpoint of preventing foreign matter from intruding into the opening H12C through the inner peripheral wall of the through hole of the third processed membrane, it is preferable that the four third processed membranes are deposited on the surface of the support frame 12C side of the unprocessed membrane. That is, it is preferable that the four third processed membranes are on the opposite side of the protective film 11C from the support frame 12C side. In other words, it is preferable that the support frame 12C, the unprocessed membrane, and the four third processed membranes are arranged sequentially from the bottom direction (negative Z-axis direction) to the top direction (positive Z-axis direction). Foreign matter intruding through the four third processed membranes includes fiber debris from the four third processed membranes.

[0215] (3.1.1.5) Material of the Protective Film The material of the protective film 11C is not particularly limited, and materials exemplified as the material of the protective film 11A can be listed. When the protective film 11C is a laminated structure, the material of the unprocessed film and the material of the pair of second processed films can be the same or different. Preferably, the material of the protective film 11C includes carbon nanotubes. Because the protective film 11C is a CNT film, good mechanical strength can be obtained.

[0216] (3.1.1.5.1) Other layers may also be laminated on the protective film 11C. An antioxidant layer may also be laminated on at least one side of the protective film 11C. Examples of antioxidant layers are the same as those exemplified as antioxidant layers that can be laminated on the protective film 11A.

[0217] When the protective film 11C includes a CNT film and other layers are laminated with the CNT film, the thickness of the CNT film is preferably greater than the thickness of the other layers. When the protective film 11C includes a CNT film and other layers are laminated with the CNT film, the outermost layer constituting the protective film 11C is preferably another layer. When the protective film 11C includes a CNT film and other layers are laminated with the CNT film, as another example, the thickness of the CNT film is preferably 50% or more, and more preferably 70% or more, relative to the overall thickness of the protective film 11C including the other layers.

[0218] (3.1.1.6)Properties of the protective film The protective film 11C preferably has the same properties as those exemplified as those of the protective film 11A.

[0219] (3.1.2) Support Frame The support frame 12C is the same as the support frame 12A except for the shape of the frame. The support frame 12C is a cylindrical object. The support frame 12C is a square frame formed by a pair of first sides 124 and a pair of second sides 125 when viewed from above. The support frame 12C has an opening H12C. The opening H12C is a through hole for EUV exposure. During EUV exposure, EUV light that has passed through the exposure area RA1 of the protective film 11C passes through the opening H12C and reaches the original.

[0220] (3.1.3) The modified protective film 11C may also have a first film portion and a second film portion. The first film portion does not have a through hole. The second film portion does not have a film portion in the region corresponding to the exposure region RA1. The second film portion is deposited on the region corresponding to the thick film portion TC of the first film portion (i.e., a pair of first central regions RA22 and a pair of second central regions RA23), and on the surface of the first film portion opposite to the support frame 12A side. The first film portion is the same as the first film portion 11A1 of the modified example of the first embodiment (see FIG10). The second film portion is the same as the second film portion 11A2 of the modified example of the first embodiment (see FIG10), except that the second film portion is deposited in the region corresponding to the thick film portion TC of the first film portion (i.e., a pair of first central regions RA22 and a pair of second central regions RA23).

[0221] (3.2) The exposure original of the third embodiment disclosed in this disclosure includes an original and a protective film assembly 10C installed on the original. The exposure original of the third embodiment of this disclosure includes the protective film assembly 10C, and therefore performs the same effect as the protective film assembly 10C. The exposure original of the third embodiment of this disclosure is the same as the exposure original of the first embodiment of this disclosure, except that the protective film assembly 10C is used instead of the protective film assembly 10A.

[0222] (3.3) Exposure Apparatus The exposure apparatus of the third embodiment of this disclosure includes a light source, an exposure plate of the third embodiment of this disclosure, and an optical system. The light source emits exposure light. The optical system guides the exposure light emitted from the light source to the exposure plate. The exposure plate is arranged such that the exposure light emitted from the light source passes through the protective film 11C and irradiates the plate. Therefore, the exposure apparatus of the third embodiment of this disclosure performs the same effect as the exposure plate of the third embodiment of this disclosure. The exposure apparatus of the third embodiment of this disclosure is the same as the exposure apparatus of the first embodiment, except that it uses the exposure plate of the third embodiment of this disclosure instead of the exposure plate of the first embodiment of this disclosure.

[0223] (3.4) Method for manufacturing the protective film assembly As a method for manufacturing the protective film assembly according to the third embodiment of this disclosure, a fifth manufacturing method and a sixth manufacturing method can be listed. Hereinafter, the fifth manufacturing method and the sixth manufacturing method will be described in turn.

[0224] (3.4.1) Fifth Manufacturing Method The fifth manufacturing method disclosed herein is a method for manufacturing a protective film assembly 10C, comprising: a step of preparing a support frame 12C; a step of preparing a first film; a step of preparing a second film; a first connecting step of connecting the support frame 12C to a portion of one of the main surfaces of the first film; and a lamination step of laminating the second film to at least a region on the other main surface of the first film corresponding to a pair of first central regions RA22 and a pair of second central regions RA23 (i.e., thick film portion TC) to form a protective film 11C.

[0225] According to the fifth manufacturing method, a protective film assembly 10C is obtained, which can suppress the damage of the protective film 11C caused by the pressure difference inside and outside the protective film assembly 10C.

[0226] The fifth manufacturing method disclosed herein is the same as the first manufacturing method disclosed herein, except that a second regionally laminated film corresponding to at least a pair of first central regions RA22 and a pair of second central regions RA23 (i.e., thick film portion TC) is laminated on the other main surface of the first film instead of a second regionally laminated film corresponding to at least a peripheral region RA2 (i.e., thick film portion TA) on the other main surface of the first film.

[0227] (3.4.2)Sixth Manufacturing Method The sixth manufacturing method disclosed herein is a method for manufacturing a protective film assembly 10C, comprising: a step of preparing a support frame 12C; a step of preparing a protective film 11C; and a second connection step of connecting the support frame 12C to the protective film 11C.

[0228] According to the sixth manufacturing method disclosed herein, a protective membrane assembly 10C is obtained, which can suppress the damage of the protective film 11C caused by the pressure difference inside and outside the protective membrane assembly 10C.

[0229] The sixth manufacturing method disclosed herein is the same as the second manufacturing method disclosed herein, except that the preparation of protective film 11C is used instead of the preparation of protective film 11A.

[0230] There is no particular limitation on the method for preparing the protective film 11C. For example, the protective film 11C may have carbon nanotubes, and the thick film portion TC (i.e., a pair of first central regions RA22 and a pair of second central regions RA23) may be formed by spray coating or inkjet printing. Spray coating or inkjet printing is acceptable as long as it is a known method.

[0231] (3.5) Semiconductor Device Manufacturing Method The semiconductor device manufacturing method of the third embodiment of this disclosure includes a reflection step and an exposure step. In the reflection step, exposure light emitted from a light source is passed through a protective film 11C of the exposure film and irradiated onto the film, and reflected by the film. In the exposure step, the exposure light reflected by the film is passed through the protective film 11C and irradiated onto the sensing substrate, thereby exposing the sensing substrate into a pattern. The reflection step and the exposure step are performed sequentially. According to the semiconductor device manufacturing method of the third embodiment of this disclosure, even when using EUV light where resolution defects caused by foreign matter are prone to become a problem, a semiconductor device with reduced resolution defects caused by foreign matter can be obtained.

[0232] The method for manufacturing a semiconductor device according to the third embodiment of this disclosure is the same as the method for manufacturing a semiconductor device according to the first embodiment of this disclosure, except that a protective film 11C is used instead of a protective film 11A. [Example]

[0233] Hereinafter, this disclosure will be described in more detail by way of embodiments, etc., but the invention disclosed herein is not limited to these embodiments. In this embodiment, the film thickness of the exposure area and the film thickness of the peripheral area are respectively performed by the method described above.

[0234] [1] Example 1 In Example 1, a protective film assembly is fabricated in such a way that the support frame 120 is a rectangular frame and the thick film portion is located in the entire area of ​​the peripheral region RC2. In the protective film assembly of Example 1, the CNT film contacts the support frame 120 and covers the entire area of ​​the opening H120 of the support frame 120.

[0235] [1.1] Preparation steps As CNTs, monolayer CNTs (crude CNTs, manufactured by Meijo Nano Carbon Co., Ltd., trade name: EC1.5-P, tube diameter: 1 nm to 3 nm, tube length: 100 nm or more) were prepared by the modified direct injection thermal decomposition synthesis method (eDIPS method).

[0236] [1.2] CNT dispersion manufacturing steps: For 30 mg of monolayer CNT synthesized by modified direct injection thermal decomposition synthesis method (eDIPS method), 70 mL of isopropanol and 30 mL of ethanol were added, and then 30 mg of polyacrylic acid was added as an additive. The mixture was stirred at 1000 rpm (revolutions per minute) at 40°C for 18 hours using a magnetic stirrer to obtain the CNT dispersion.

[0237] [1.3] CNT film manufacturing steps: An 8-inch silicon wafer (hereinafter also referred to as "silicon substrate") was prepared. The CNT dispersion was spin-coated onto the silicon substrate at a rotation speed of 1500 rpm, thereby obtaining a CNT film 110A (hereinafter also referred to as "CNT film 110A") on the silicon substrate. The size of the CNT film 110A is larger than a square with a side length of 10 mm. Hereinafter, the silicon substrate and the CNT film 110A formed on the silicon substrate are collectively referred to as "substrate with film (A)".

[0238] After washing the CNT film 110A with water to remove the polyacrylic acid in the CNT film 110A and drying it, the substrate (A) with the film is immersed in water. Then, only the CNT film 110A is left in the water while only the silicon substrate is removed from the water, thereby peeling the CNT film 110A from the silicon substrate, thus creating a CNT film 110A with a mesh structure in a state of floating on the surface of the water.

[0239] [1.4] As a support frame, a silicon frame 120 (hereinafter also referred to as "support frame 120") as shown in FIG14A is prepared. The support frame 120 is a cylindrical object. The support frame 120 has an opening H120. The opening H120 extends through the support frame 120 along the thickness direction D of the support frame 120. The outline of the opening H120 viewed from one side of the thickness direction D of the support frame 120 is a square with a side length of 10 mm.

[0240] The CNT membrane 110A, which is floating on the surface of the water, is retrieved using the support frame 120. As shown in FIG14B, the CNT membrane 110A is placed on the support frame 120 to obtain the first test specimen 201. The CNT membrane 110A is in contact with the support frame 120 and covers the entire area of ​​the opening H120 of the support frame 120.

[0241] By performing the preparation step, the CNT dispersion manufacturing step, and the CNT film manufacturing step, a substrate (A) with a film is obtained again. As shown in FIG. 14C, a through-hole H110 is formed on the CNT film 110A of the substrate (A) with a film obtained by mechanically rubbing it, to obtain a CNT film 110B. The through-hole H110 of the CNT film 110B is formed along the thickness direction of the CNT film 110B. The outline of the through-hole of the CNT film 110B, viewed from one side of the silicon substrate 130 in the thickness direction, is a square with a side length of 8 mm.

[0242] Hereinafter, the silicon substrate 130 and the CNT film 110B formed on the silicon substrate 130 are collectively referred to as "substrate with film (B)".

[0243] For the substrate (B) with the film, the CNT film 110B is washed with water to remove the polyacrylic acid in the CNT film 110B and then dried, allowing the substrate (B) with the film to permeate into water. Then, the CNT film 110B is left in the water while only the silicon substrate 130 is removed from the water, thereby peeling the CNT film 110B off from the silicon substrate 130.

[0244] The CNT film 110B is retrieved using the first test body 201 (see Figure 14B), and the CNT film 110B is disposed on the CNT film 110A to form a protective film 110, which serves as a protective film assembly, and the second test body 202 shown in Figure 15 is obtained.

[0245] The second test body 202 includes a protective film 110 and a support frame 120. The protective film 110 has a self-supporting film region RC that covers the opening H120 of the support frame 120. The self-supporting film region RC includes an exposure region RC1 and a peripheral region RC2. The peripheral region RC2 surrounds the exposure region RC1.

[0246] The film thickness of the exposure region RC1 and the film thickness of the peripheral region RC2 of the second test body 202 were determined by the method described above. The film thickness of the exposure region RC1 of the second test body 202 was 15 nm. The film thickness of the peripheral region RC2 of the second test body 202 was 30 nm.

[0247] [2] Comparative Example 1 Similar to Example 1, a first test body 201 was obtained as a protective film assembly. In Comparative Example 1, the CNT film 110A corresponds to the protective film 110. The film thickness of the exposure region RC1 and the film thickness of the peripheral region RC2 of the first test body 201 were measured by the method described above. The film thickness of the exposure region RC1 of the first test body 201 was 15 nm. The film thickness of the peripheral region RC2 of the second test body 202 was 15 nm.

[0248] [3] Evaluation [3.1] Destruction evaluation based on expansion test The protective membrane assembly obtained in Example 1 and Comparative Example 1 was subjected to a destruction evaluation based on the expansion test of the protective membrane 110 as described below. As shown in FIG16A, the protective membrane assembly was fixed in the chamber 31 for expansion test. At this time, the protective membrane 110 was configured to be the inner side of the chamber 31. By flowing compressed air inside the chamber 31, the inside of the chamber 31 was pressurized, and a pressure ΔP was applied to the self-supporting membrane region RC of the protective membrane 110. The pressure ΔP applied to the protective membrane 110 was represented by the difference between the pressure (atmospheric pressure) P1 outside the chamber 31 and the pressure P2 inside the chamber 31, and was measured by a differential pressure gauge 32. ΔP was adjusted by controlling the flow rate of the compressed air flowing inside the chamber 31 using a flow meter (not shown).

[0249] As shown in Figure 16B, the airflow rate inside chamber 31 is increased by 10 sccm at 1-minute intervals, and the resulting differential pressure ΔP is recorded. If the protective membrane 110 is damaged, a hole is formed in the protective membrane 110, thus the differential pressure ΔP decreases significantly. Based on the value of the differential pressure ΔP before the protective membrane 110 is about to be damaged, the "rupture pressure" is measured. The measurement results of the rupture pressure are shown in Table 2.

[0250] [Table 2] Self-supporting membrane region Expansion test Film thickness in the peripheral region (film thickness in the thick film portion) (nm) Film thickness in the exposure area (nm) Film thickness ratio Pressure that causes membrane rupture (Pa) evaluate Example 1 30 15 2.0 250 A Comparative Example 1 15 15 1.0 131 B

[0251] In Table 2, the term "film thickness ratio" refers to the ratio of the film thickness of the peripheral region RC2 (thick film portion) to the film thickness of the exposure region RC1. In Table 2, "A" indicates that, while maintaining the film thickness of the exposure region RC1, damage to the protective film 110 caused by the pressure difference between the inside and outside of the protective film assembly can be suppressed. In Table 2, "B" indicates that, while maintaining the film thickness of the exposure region RC1, damage to the protective film 110 caused by the pressure difference between the inside and outside of the protective film assembly cannot be suppressed.

[0252] As shown in Table 2, the protective film assembly of Example 1 includes: a support frame 120 having an opening H120, and a protective film 110 covering the opening H120 and supported by the support frame 120. The protective film 110 has a self-supporting film region RC covering the opening H120. The self-supporting film region RC includes an exposure region RC1 and a peripheral region RC2 surrounding the exposure region RC1. The peripheral region RC2 has a thicker film portion that is thicker than the film thickness of the exposure region RC1. The support frame 120 is a rectangular frame. The thicker film portion is located over the entire area of ​​the peripheral region RC2. Therefore, the film rupture pressure of the protective film assembly of Example 1, i.e., when the film thickness of the peripheral region RC2 is thicker than the film thickness of the exposure region RC1, is 250 Pa. On the other hand, the film rupture pressure of the protective film assembly of Comparative Example 1, i.e., when the film thickness of the peripheral region RC2 is not thicker than the film thickness of the exposure region RC1, is 131 Pa. Based on these results, it can be seen that by making the film thickness of the peripheral region RC2 greater than that of the exposure region RC1, while maintaining the film thickness of the exposure region RC1 (while maintaining the transmittance of EUV light), damage to the protective film caused by the pressure difference inside and outside the protective film assembly can be suppressed.

[0253] [4] Example 2 In Example 2, a protective film assembly is fabricated in such a way that the support frame 120 is a square frame and the thick film portion TX exists along the center of each of the four sides of the support frame 120. In the protective film assembly of Example 2, similarly to Example 1, the protective film 111 contacts the support frame 120 and covers the entire area of ​​the opening H120 of the support frame 120.

[0254] [4.1] Preparation steps, CNT dispersion manufacturing steps, and CNT film manufacturing steps were performed in Example 1 to re-obtain multiple substrates (A) with films. Similar to Example 1, a portion of the multiple substrates (A) with films were washed with water and allowed to permeate into water to manufacture CNT film 110A.

[0255] [4.2] The configuration is the same as that in Example 1. The CNT film 110A is retrieved using the support frame 120 to obtain the first test specimen 201 (see Figure 13B).

[0256] As shown in FIG17A, four CNT films 110C are obtained from a substrate (A) with a film obtained by mechanical rubbing. Each CNT film 110C includes a pair of rectangular shapes with one side of 1.4 mm to 3.0 mm and a width of 2.0 mm, and another pair of rectangular shapes with one side of 1.4 mm to 3.0 mm and a width of 2.0 mm.

[0257] Hereinafter, the silicon substrate 140 and the four CNT films 110C formed on the silicon substrate 140 are collectively referred to as "substrate with films (C)".

[0258] For the substrate (C) with the film, four CNT films 110C are washed with water to remove the polyacrylic acid in the CNT films 110C and then dried, allowing the substrate (C) with the film to permeate into water. Next, the four CNT films 110C are left in the water while only the silicon substrate 140 is removed from the water, thereby peeling the CNT films 110C off the silicon substrate 140.

[0259] Using the first test body 201 (see Figure 12B), each of the four CNT films 110C is retrieved and disposed at the center of a pair of first sides and the center of a pair of second sides of the support frame to form a protective film 111. Thereby, as a protective film assembly, the test body 203 shown in Figure 17B is obtained.

[0260] The test body 203 includes a protective film 111 and a support frame 120. As shown in FIG18, the protective film 111 of the test body 203 has a self-supporting film region RC that covers the opening H120 of the support frame 120. The self-supporting film region RC includes an exposure region RC1 and a peripheral region RC2. The peripheral region RC2 surrounds the exposure region RC1.

[0261] The peripheral region RC2 has four thick film portions TX. The support frame 120 is a square-shaped frame formed by a pair of first sides 1201 and a pair of second sides 1202. The length of the first sides 1201 is the same as the length of the second sides 1202. Two thick film portions TX are located in the peripheral region RC2 along a first extending direction D1 extending from the first sides 1201, forming a pair of first central regions RC21. Two thick film portions TX are located in the peripheral region RC2 along a second extending direction D2 extending from the second sides 1202, forming a pair of second central regions RC22.

[0262] The average edge coverage of the four thick film portions TX is 13%. The maximum edge coverage of the four thick film portions TX is 15%. The minimum edge coverage of the four thick film portions TX is 11%. The "edge coverage" of the thick film portions TX formed along a pair of first edges 1201 is expressed in the first extending direction D1 as the ratio of the first length to the length in the opening H120 of the first edge portion 1201 of the support frame 120. The "first length" is expressed in the first extending direction D1 as the shorter of the length from the center of the first edge portion 1201 to the end of one side of the thick film portion TX and the length from the center of the first edge portion 1201 to the end of the other side of the thick film portion TX. The "edge coverage" of the thick film portions TX formed along a pair of second edges 1202 is expressed in the second extending direction D2 as the ratio of the second length to the length in the opening H120 of the second edge portion 1202 of the support frame 120. "Second length" refers to the shorter of the length from the center of the second side portion 1202 to one end of the thick film portion TX in the second extending direction D2, and the shorter of the length from the center of the second side portion 1202 to the other end of the thick film portion TX. For example, when the thick film portion TX is located in the region between the point where 13% of the length of the opening H120 is extended from the center of the first side portion 1201 to one side and the point where 13% of the length of the opening H120 is extended to the other side in the first extending direction D1 (in other words, when the thick film portion TX is located in the first central region RC21, which is 26% of the length of the opening H120 in the first extending direction D1), the coverage is 13%.

[0263] The film thickness of the exposure region RC1 and the film thickness of the peripheral region RC2 of the test body 203 were measured by the method described above. The film thickness of the exposure region RC1 of the test body 203 was 23 nm. The film thickness of the thick film portion TX in the peripheral region RC2 of the test body 203 was 47 nm, and the film thickness of the area that was not the thick film portion TX was 23 cm.

[0264] [5] Example 3 Except for changing the film thickness of the peripheral area and the film thickness of the exposure area as shown in Table 3, the test body 203 was obtained in the same manner as in Example 2.

[0265] [6] Comparative Example 2 Similar to Example 2, a first test body 201 was obtained as a protective film assembly. In Comparative Example 2, the CNT film 110A corresponds to the protective film 110. The film thickness of the exposure region RC1 and the film thickness of the peripheral region RC2 of the first test body 201 were measured by the method described above. The film thickness of the exposure region RC1 of the first test body 201 was 24 nm. The film thickness of the peripheral region RC2 of the second test body 202 was 24 nm.

[0266] [7] Evaluation [7.1] Destruction evaluation based on expansion test Similar to the destruction evaluation based on expansion test, the membrane rupture evaluation of the protective membrane assemblies of Example 2, Example 3 and Comparative Example 2 was performed. The measurement results of the membrane rupture pressure are shown in Table 3.

[0267] [Table 3] Self-supporting membrane region Expansion test Film thickness in peripheral area Film thickness in the exposure area (nm) Film thickness ratio Edge coverage rate (%) Pressure that causes membrane rupture (Pa) evaluate Thick film portion (nm) Not the thick film portion (nm) average maximum Minimum Example 2 48 twenty four twenty four 2.0 13 15 11 468 A Example 3 47 twenty three twenty three 2.0 10 12 7 424 A Comparative Example 2 twenty four twenty four twenty four 1.0 0 0 0 310 B

[0268] In Table 3, the term "film thickness ratio" refers to the ratio of the film thickness of the thick film portion TX in the peripheral region RC2 to the film thickness of the exposure region RC1. In Table 3, the term "edge coverage ratio" refers to the ratio of the location having the thick film portion TX in the first extension direction D1 to the length of the opening H120 in the first edge portion 1201, or the ratio of the location having the thick film portion TX in the second extension direction D2 to the length of the opening H120 in the second edge portion 1202. In Table 3, the term "average" of "edge coverage ratio" refers to the average edge coverage ratio of the four thick film portions TX. In Table 3, the term "maximum" of "edge coverage ratio" refers to the maximum value of the edge coverage ratio of the four thick film portions TX. In Table 3, the term "minimum" of "edge coverage ratio" refers to the minimum value of the edge coverage ratio of the four thick film portions TX. In Table 3, "A" indicates that, while maintaining the film thickness of the exposure area RC1, damage to the protective film 111 caused by the pressure difference inside and outside the protective film assembly (i.e., test body 203) can be suppressed. In Table 3, "B" indicates that, while maintaining the film thickness of the exposure area RC1, damage to the protective film 111 caused by the pressure difference inside and outside the protective film assembly (i.e., test body 203) cannot be suppressed.

[0269] As shown in Table 3, the protective film assembly of Embodiments 2 and 3 includes: a support frame 120 having an opening H120, and a protective film 111 covering the opening H120 and supported by the support frame 120. The protective film 111 has a self-supporting film region RC covering the opening H120. The self-supporting film region RC includes an exposure region RC1 and a peripheral region RC2 surrounding the exposure region RC1. The peripheral region RC2 has a thick film portion TX that is thicker than the film thickness of the exposure region RC1. The support frame 120 is a rectangular frame. Two thick film portions TX are located in a pair of first central regions RC21. Two thick film portions TX are located in a pair of second central regions RC22. Therefore, the film rupture pressure of the protective film assembly of Embodiments 2 and 3, i.e., when the film thickness of the first central region RC21 and the second central region RC22 is thicker than the film thickness of the exposure region RC1, is 424 Pa or more. On the other hand, the pressure at which the protective film assembly of Comparative Example 2, namely the first central region RC21 and the second central region RC22, has a film thickness that is not greater than that of the exposure region RC1, is 310 Pa. Based on these results, it can be seen that when the support frame 120 is a square frame, by making the film thickness of the first central region RC21 and the second central region RC22 greater than that of the exposure region RC1, while maintaining the film thickness of the exposure region RC1 (while maintaining the transmittance of EUV light), damage to the protective film caused by the pressure difference inside and outside the protective film assembly can be suppressed.

[0270] The disclosure of Japanese Patent Application No. 2021-061642, filed on March 31, 2021, is incorporated herein by reference in its entirety. All documents, patent applications, and technical specifications described in this specification are incorporated herein by reference to the same extent that each document, patent application, and technical specification is specifically and individually described herein by reference. [Simplified Explanation of the Diagram]

[0013] Figure 1 is a schematic diagram illustrating the change of the previous protective film assembly when the exposure apparatus changes from an atmospheric pressure state to a vacuum state. Figure 2 is a schematic diagram illustrating the change of the previous protective film assembly when the exposure apparatus changes from a vacuum state to an atmospheric pressure state. Figure 3A is a schematic diagram showing an example of the inner edge of the previous protective film assembly of the support frame under atmospheric pressure before evacuation. Figure 3B is a schematic diagram showing an example of the inner edge of the previous protective film assembly of the support frame when the environment in which the protective film assembly is placed changes from a vacuum environment to an atmospheric pressure environment after exposure. Figure 3C is a schematic diagram showing another example of the inner edge of the previous protective film assembly of the support frame when the environment in which the protective film assembly is placed changes from a vacuum environment to an atmospheric pressure environment after exposure. Figure 4 is a top view of the protective film assembly showing the stress distribution simulation results when the differential pressure to the protective film is set to 3 Pa when the support frame is rectangular. Figure 5 is a top view showing the appearance of the protective film assembly according to the first embodiment of this disclosure. Figure 6 is a cross-sectional view along line VV in Figure 5. Figure 7 is a schematic top view showing a microscope image of a portion of the periphery of the opening on the protective film of the protective film assembly of the first embodiment of the present disclosure. Figure 8A is an explanatory diagram illustrating a method for transferring the self-supporting film region of the protective film of the first embodiment of the present disclosure onto a silicon substrate. Figure 8B is an explanatory diagram illustrating a method for transferring the self-supporting film region of the protective film of the first embodiment of the present disclosure onto a silicon substrate. Figure 9A is a top view of a silicon substrate on which the portion corresponding to the self-supporting film region of the protective film of the first embodiment of the present disclosure has been transferred. Figure 9B is a cross-sectional view along line IXB-IXB of Figure 9A. Figure 10 is a cross-sectional view of a protective film assembly of a modified example of the first embodiment of the present disclosure. Figure 11 is a schematic cross-sectional view of an exposure apparatus, namely an EUV exposure apparatus, of the first embodiment of the present disclosure. Figure 12 is a top view showing the appearance of the protective film assembly of the second embodiment of the present disclosure. Figure 13 is a top view showing the appearance of the protective film assembly of the third embodiment of the present disclosure. Figure 14A is an explanatory diagram illustrating a method for manufacturing the protective film assembly of Example 1. Figure 14B is an explanatory diagram illustrating the manufacturing method of the protective membrane assembly of Example 1. Figure 14C is an explanatory diagram illustrating the manufacturing method of the protective membrane assembly of Example 1. Figure 15 is a cross-sectional view of the protective membrane assembly of Example 1. Figure 16A is a schematic diagram showing the measuring device in the expansion test. Figure 16B is a graph showing the pressure difference between the inside and outside of the protective membrane assembly relative to the elapsed time in the expansion test. Figure 17A is an explanatory diagram illustrating the manufacturing method of the protective membrane assembly of Example 2. Figure 17B is an explanatory diagram illustrating the manufacturing method of the protective membrane assembly of Example 2. Figure 18 is a cross-sectional view of the protective membrane assembly of Example 1.

Claims

1. A protective film assembly, comprising: The support frame has an opening; and a protective film covering the opening, supported by the support frame, the protective film having a self-supporting film region covering the opening, the self-supporting film region including an exposure area and a peripheral region surrounding the exposure area, the peripheral region having a thick film portion with a film thickness greater than that of the exposure area, and the protective film assembly satisfying either (i) or (ii) below: (i) the support frame is a rectangular frame formed by a pair of long sides and a pair of short sides, the thick film portion being at least located in the peripheral region along a pair of long side regions formed in the extending direction of the long side, the pair of long side regions representing the area between two locations in the peripheral region, in the extending direction, from the center of the long side towards one side and the other side, respectively away from the opening showing the long side portion by a distance of at least 5% of the length of the opening showing the long side portion; (ii) the support frame is a square frame formed by a pair of first sides and a pair of second sides, the thick film portion being at least located in the peripheral region... A pair of first central regions are formed along the first side in a first extending direction extending from the first side, and a pair of second central regions are formed along the second side in a second extending direction extending from the second side. The pair of first central regions represent the area between two locations in the peripheral region that are at least 5% of the length of the opening showing the first side from the center of the first side in the first extending direction toward one side and the other side. The pair of second central regions represent the area between two locations in the peripheral region that are at least 5% of the length of the opening showing the second side from the center of the second side in the second extending direction toward one side and the other side. The film thickness of the thick film portion is more than 1.5 times and less than 100 times the film thickness of the exposure area.

2. The protective film assembly as claimed in claim 1, wherein, The protective film comprises carbon nanotubes.

3. The protective film assembly as claimed in claim 1, wherein, The support frame is in contact with the protective film.

4. The protective film assembly as claimed in claim 1, wherein, The protective film has: a first film portion without through holes; and a second film portion without a film portion in the region corresponding to the exposure area. The first film portion has a first carbon nanotube layer containing carbon nanotubes, and the second film portion has a second carbon nanotube layer containing carbon nanotubes. The total thickness of the first carbon nanotube layer and the second carbon nanotube layer in the thick film portion is more than 1.5 times and less than 100 times the thickness of the first carbon nanotube layer in the exposure area.

5. The protective film assembly as claimed in claim 4, wherein, The second film portion is deposited on the region of the first film portion corresponding to the thick film portion, and is deposited on the surface of the first film portion opposite to the support frame side.

6. An exposure of the original, including: Original version; And a protective film assembly as described in any one of claims 1 to 5, installed on the original.

7. An exposure apparatus, comprising: The light source emits exposure light; As requested in item 6, the original version should be exposed; And an optical system that guides the exposure light emitted from the light source to the exposure template, the exposure template being configured such that the exposure light emitted from the light source passes through the protective film and illuminates the template.

8. The exposure apparatus as claimed in claim 7, wherein, The exposure light is extreme ultraviolet light.

9. A method for manufacturing a protective film assembly, comprising: The steps for preparing the support frame; The steps for preparing the protective film; The process includes a connection step, in which the support frame is connected to the protective film.

10. A method for manufacturing a protective film assembly as described in claim 9, wherein, The protective film has carbon nanotubes, and in the step of preparing the protective film, the thick film portion is formed by spray coating or inkjet printing.

11. A method for manufacturing a protective film assembly, comprising: The steps for preparing the support frame; Steps for preparing the first membrane; Steps for preparing the second membrane; The connection step involves connecting the support frame to a portion of one of the main surfaces of the first membrane; The process includes a lamination step, whereby the second film is laminated onto another main surface of the first film to form the protective film.

12. A method for manufacturing a protective film assembly as claimed in claim 11, wherein, Each of the first membrane and the second membrane comprises a carbon nanotube.

13. A method for manufacturing the protective film assembly as described in claim 9, wherein, The protective film comprises a laminated film consisting of two or more carbon nanotube films, including carbon nanotubes.

14. A method for manufacturing a semiconductor device, comprising: The steps include: illuminating the original with exposure light emitted from a self-light source through the protective film of the original as described in claim 6, and reflecting it through the original; and exposing the original in a patterned manner by passing the exposure light reflected through the original through the protective film onto the sensing substrate.

Images