WO2020008978A1 - Reinforced pellicle film and method for manufacturing same - Google Patents

Abstract

The objective of the present invention is to provide a reinforced pellicle film that suppresses the generation of outgas, has high heat resistance and durability, and has excellent EUV transmissivity. A reinforced pellicle film characterized by comprising a pellicle film constituted from a carbon film, and a support material layer formed on one or both surfaces of the pellicle film and having a plurality of openings, the pellicle film and the support material layer comprising the same carbon material.

Description

Reinforced pellicle film and method for manufacturing reinforced pellicle film

The present invention relates to a reinforced pellicle film and a method for producing the reinforced pellicle film.

In recent years, extreme ultraviolet lithography technology has been developed for finer semiconductor processing. In a photolithography apparatus using extreme ultraviolet light, a pellicle film is used as a dust-proof protective film to be attached to a photomask. It is useful as a member for preventing
This pellicle film is required to have not only the transmittance of extreme ultraviolet light but also the diffusion and strength of heat derived from extreme ultraviolet light.

For example, as a pellicle film having improved film strength (also referred to as a reinforced pellicle film), a composite film in which the pellicle film is supported by a mesh-like substrate made of silicon, metal, or the like, or a supporting material such as a metal wire is known. (Patent Document 1, Patent Document 2).
As shown in FIG. 2, for example, the reinforced pellicle films of Patent Documents 1 and 2 are composed of a pellicle film 1b and a support material layer 4 having a plurality of openings formed on one surface of the pellicle film. The membrane 1b and the support material layer 4 are joined with an adhesive.

WO 2014/188710 pamphlet JP 2015-18228 A

Although a high film strength is required for the reinforced pellicle film, there is a trade-off between the film strength and the EUV transmittance, and there is a problem that the film strength is low even if the EUV transmittance is sufficient.
Further, when bonding the pellicle film and the support material layer, there is also a problem that the adhesive volatilizes at a high temperature and outgas is generated.
Furthermore, the heat resistance of the conventional support material layer is insufficient, and the width (line width) of the linear portion constituting the opening tends to be large in terms of maintaining strength, and the EUV transmittance is also low. affect. On the other hand, depending on the material of the support material layer, there is a concern that the material may be damaged due to a difference in coefficient of thermal expansion when heated by EUV irradiation.

In view of the above problems, an object of the present invention is to provide a reinforced pellicle film and a method for manufacturing the reinforced pellicle film, which suppress outgassing, have high heat resistance and durability, and have excellent EUV transmittance.
On the other hand, another object of the present invention is to provide a reinforced pellicle film that does not break or peel even when heated, and a method for manufacturing the pellicle film.

The gist of the present invention that has solved the above problems is as follows.
[1] A pellicle film composed of a carbon film, and a support material layer having a plurality of openings formed on one or both surfaces of the pellicle film, wherein the pellicle film and the support material layer are made of the same carbon material. A reinforced pellicle membrane characterized in that:
[2] The reinforced pellicle film according to [1], wherein the carbon film and the support material layer are a carbonaceous film or a graphite film.
[3] The reinforced pellicle film according to [1] or [2], wherein the carbon film and the support material layer are integrally formed.
[4] The reinforced pellicle film according to any one of [1] to [3], wherein the carbon film and the support material layer are formed of the same carbon material without interposing an adhesive layer or a bonding layer.
[5] The reinforced pellicle membrane according to any one of [1] to [4], wherein the opening ratio of the support material layer is 80% or more.
[6] The reinforced pellicle film according to any one of [1] to [5], wherein the pellicle film has a thickness of 1 to 100 nm and the support material layer has a thickness of 1 to 500 nm.
[7] A method for producing a reinforced pellicle membrane according to any one of [1] to [6],
Forming a first coating layer having a predetermined opening pattern on a carbon film thicker than the pellicle film,
A step of laminating a second coating layer on each of the carbon film and the first coating layer,
Removing both the first coating layer and the second coating layer stacked on the first coating layer from the carbon film while leaving the second coating layer stacked on the carbon film;
A step of starting etching for removing the carbon film in the thickness direction from the second coating layer forming surface side;
After the support material layer is exposed from the carbon film, the method includes a step of terminating the etching, and a step of removing the second coating layer, and is formed on one or both surfaces of the pellicle film composed of the carbon film and the pellicle film. A method for manufacturing a reinforced pellicle membrane, wherein the support material layer having a plurality of openings is made of the same carbon material.
[8] The manufacturing method according to [7], wherein the etching is performed on one side or both sides of the carbon film.
[9] The method according to [7] or [8], wherein the first coating layer is formed of a resist, and the second coating layer is formed of a metal.
[10] The production method according to any one of [7] to [9], wherein after the etching, the second coating layer is removed with an acid.
[11] The method according to any one of [7] to [10], wherein the second coating layer is made of aluminum.

ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of an outgas is suppressed, heat resistance and durability are high, and the manufacturing method of a reinforced pellicle film excellent in EUV transmittance can be provided.
Further, according to the present invention, a reinforced pellicle film having no difference in linear expansion coefficient between the carbon film and the support material layer is obtained, so that breakage or peeling does not occur even during heating.

FIG. 1 is a schematic flow chart showing an example of the method for producing a reinforced pellicle film of the present invention. FIG. 2 is a diagram showing each parameter when calculating the aperture ratio of the support material layer in the reinforced pellicle film. FIG. 3 is a perspective view showing an example of the reinforcing pellicle film of the present invention. FIG. 4 is a perspective view showing another example of the reinforcing pellicle film of the present invention. FIG. 5 is a perspective view showing another example of the reinforcing pellicle film of the present invention.

The meaning of the terms used in the present specification will be explained.
(1) Extreme UV (EUV, Extreme Ultra Violet)
EUV as used herein means light having a wavelength of 5 nm to 30 nm, preferably 5 nm to 13.5 nm. The pellicle composite of the present invention is preferably used for the EUV lithography method.

(2) Pellicle Complex The pellicle complex is used to protect a pattern surface of a photomask reflecting an exposure pattern, and includes a pellicle film and a frame portion (pellicle frame) provided on an outer edge of the pellicle film. Be composed. The shape of the pellicle film is not particularly limited, and can be appropriately selected from a circle, an ellipse, a polygon, and the like. The preferred shape of the pellicle film is a square such as a square or a rectangle. It is preferable to use a reinforced pellicle film described later as the pellicle film of the present invention.

(3) Pellicle frame The pellicle frame means a frame formed on the pellicle film, and is used to cover the photomask with the pellicle complex. The pellicle frame may have a vent to keep the pressure inside the exposure apparatus and inside the pellicle complex constant.

(4) Reinforced pellicle membrane Refers to the membrane part of the pellicle complex. In the present invention, the reinforcing pellicle film includes a pellicle film made of a carbon film (A) and a support material layer (B) having a plurality of openings formed on one or both sides of the pellicle film. The support material layer (B) will be described later.

(5) Carbon film (A)
The carbon film (A) means a film substantially composed of carbon atoms, and is used as a constituent member of the pellicle film in the present invention. The thickness of the carbon film is, for example, 1,000 nm or less, preferably 1 nm to 100 nm, more preferably 1 nm to 50 nm, and particularly preferably 1 nm to 30 nm.
In the present invention, the thickness of the carbon film is synonymous with the thickness of the reinforcing pellicle film and the pellicle film.
The area of the carbon film is, for example, 100 cm ² or more, preferably 120 cm ² or more, and more preferably 150 cm ² or more and 3000 cm ² or less. Although the shape of the carbon film is not particularly limited, it is preferably a rectangle or a square, and the length of one side is, for example, 10 cm or more, preferably 15 cm or more, and more preferably 20 cm or more. The transmittance of the EUV carbon film having a wavelength of 13.5 nm is, for example, 55% or more and 99% or less, preferably 74% or more and 99% or less, and more preferably 84% or more and 99% or less.
The surface roughness (Sa) of the carbon film is, for example, 0.1 nm or more and 500 nm or less. The surface roughness is preferably 1 nm or more, more preferably 3 nm or more, still more preferably 5 nm or more, preferably 350 nm or less, more preferably 200 nm or less, even more preferably 100 nm or less. The surface roughness Sa means an arithmetic average thickness obtained based on ISO 25178. The EUV transmittance improves as the surface roughness decreases.

The carbon film includes a carbonaceous film, a diamond-like carbon film (DLC), a graphene film, a graphite film, and the like, and the carbonaceous film includes an amorphous carbon film, an amorphous carbon film, and the like. Preferred carbon films are a carbonaceous film, a graphene film, a graphite film and the like, and more preferably a carbonaceous film and a graphite film.

The carbonaceous film can be distinguished from the graphene film or the graphite film based on the results of the laser Raman measurement. In the case of laser Raman spectroscopy, a G band due to the graphite structure appears around 1575 to 1600 cm ^-1 , and a D band due to the amorphous carbon structure appears around 1350 to 1360 cm ^-1 . The ratio (I (D) / I (G); D / G band intensity ratio) between the G band intensity (I (G)) and the intensity of the D band (I (D)) in the Raman spectrum is 0.5. Those exceeding the above are classified as carbonaceous films, and those having a D / G band intensity ratio of 0.5 or less are classified as graphene films or graphite films.

Ｄ The D / G band intensity ratio of the carbonaceous film is preferably 2.5 or less, more preferably 0.7 or more and 1.5 or less, and particularly preferably 0.9 or more and 1.3 or less. The D / G band intensity ratio of Glassy @ carbon, which is a typical amorphous carbon produced by a method such as vapor deposition or sputtering, is about 1.8 to 2.0. A carbonaceous film having a D / G band intensity ratio of 1.5 or less can be obtained or manufactured by an appropriate method, and for example, is preferably manufactured by carbonizing an aromatic polyimide film. The aromatic polyimide film is made of, for example, a polyamic acid prepared by combining pyromellitic dianhydride, 4,4-diaminodiphenyl ether (ODA), and p-phenylenediamine (PDA) with an acid anhydride such as acetic anhydride. A film obtained by a chemical cure method in which imidization is performed using a dehydrating agent typified by a substance or a tertiary amine such as picoline, quinoline, isoquinoline, or pyridine as an imidization accelerator is preferable. The carbonization treatment (heat treatment) of the aromatic polyimide film may be performed at about 900 to 2000 ° C. for 15 to 30 minutes in an atmosphere of an inert gas such as nitrogen, argon, or a mixed gas of argon and nitrogen. The heating rate up to the carbonization temperature is not particularly limited, but is, for example, 5 ° C./min or more and 15 ° C./min or less. After the carbonization heat treatment, the material may be cooled to room temperature by natural cooling or the like.

厚 The thickness of the carbonaceous film can be selected from the same range as the thickness of the carbon film described above. The surface roughness (Sa) of the carbonaceous film is the same as the surface roughness (Sa) of the carbon film.

Ｄ The D / G band intensity ratio of the graphene film or the graphite film is 0 or more and 0.5 or less, preferably 0 or more and 0.1 or less, more preferably 0 or more and 0.05 or less.

Examples of the graphene film include a graphene single-layer film and a graphene multilayer film having a thickness of less than 5 nm. The graphite film is a film having a thickness of 5 nm or more, and the preferable range of the thickness is the same as the preferable range of the carbon film.
The surface roughness (Sa) of the graphite film is the same as the surface roughness (Sa) of the carbon film described above.

The graphene film or the graphite film is formed by heating a carbonaceous film obtained from the aromatic polyimide film at a temperature higher than the carbonization temperature, for example, higher than 2000 ° C. and 3300 ° C. or lower, preferably 2200 ° C. or higher and 3200 ° C. or lower, more preferably 2400 ° C. or higher and 3000 or higher. It can be obtained by performing heat treatment at a temperature of not more than ℃.

(6) Support material layer (B)
The support material layer (B) is a layer that plays the role of reinforcing the strength of the pellicle film while maintaining the EUV transmittance at a high level. The support material layer may be referred to as a support material portion, or may be composed of only the support material.
The support material layer (B) has a plurality of openings formed on one or both sides of a pellicle film composed of a carbon film (A). The opening may have any shape, and is preferably a quadrangle such as a circle, an ellipse, a triangle, a rectangle, a square, and a rhombus, a polygon such as a pentagon, a hexagon, or a combination thereof.
The opening may be a portion formed by a convex portion and a concave portion, the convex portion may directly constitute a support material layer, and the concave portion may be a portion where the carbon film (A) is exposed (the carbon film). (A) surface portion).
When the opening is, for example, a square, the support material layer may have a stripe-shaped opening, or may have an opening formed by two or more stripes intersecting each other.
It is preferable that the entire support material layer forms a mesh-like film having the opening.

The thickness of the support material layer is preferably 1 nm to 500 nm, more preferably 5 nm to 300 nm, and further preferably 10 nm to 150 nm. The thickness of the support material layer can be measured by, for example, a laser microscope. The thickness of the opening may be the same as or different from the thickness of the support material layer.

(4) In the cross section of the reinforcing pellicle film, the opening of the support material layer is preferably formed of a pair of adjacent convex portions (also referred to as linear portions). When the convex portion of the opening (the convex portion is a convex portion shown in a plane perpendicular to the surface of the reinforcing pellicle film in this specification) is a regular polygon, the wire diameter w of the opening of the support material layer is , Side length Q, period P, aperture L, and aperture ratio O (see FIG. 2). These parameters are as described in JP-A-2015-18228.

The thickness of the convex portion forming the opening of the support material layer is expressed as a wire diameter w of the opening of the support material layer. When the cross-sectional shape of the convex portion is square, the line width is w1 and the line thickness is w2. When the cross-sectional shape is square or circular, w1 = w2 = w.
The line width w1 is, for example, 1 nm to 5000 nm, preferably 5 nm to 4000 nm, and more preferably 10 nm to 3000 nm.
The line thickness w2 is, for example, 1 nm to 400 nm, preferably 5 nm to 200 nm, and more preferably 10 nm to 100 nm. Hereinafter, unless otherwise specified, the cross-sectional shape of the convex portion is assumed to be a square for convenience.

When the opening of the support material layer is a regular polygon, the dimension of the side of the opening (the length between the center lines of the line width w1 of the adjacent protrusions) is expressed as the side length Q (see FIG. 2). Not shown).
The side length Q is, for example, 1 μm to 5000 μm, preferably 5 μm to 4000 μm, and more preferably 10 μm to 3000 μm.

As shown in FIG. 2, the period P of the openings of the support material layer is the dimension of the smallest periodic repeating unit of the rectangular shape when the two-dimensional plane is completely filled with the regular polygon (adjacent rectangular shape). Of the same side in the above). When the convex portions forming the openings of the support material layer are square, the dimensions of the same side in adjacent rectangles are the same, and the period P has one value and the same value as the side length Q. When the opening of the material layer is a regular triangle and a regular hexagon, the period may be different depending on the direction.
The cycle may be the same as the side length.

The aperture L of the support material layer is expressed as a value obtained by subtracting the wire diameter w from the side length Q. That is, the aperture L of the support material layer is the dimension of the opposite sides of the regular polygon of the minimum unit formed by the openings of the projections. The mesh ratio D of the support material layer is expressed as a value (L / Q) obtained by dividing the opening L by the side length Q.
Mesh ratio D = L / Q = 1−w1 / Q (A)
The mesh ratio D is determined according to the shape of the opening of the support material layer. When the support material layer has an opening of a regular triangle, the mesh ratio is D (A), and when the support material layer has a square opening. When the support material layer has a regular hexagonal opening, the mesh ratio may be indicated as D (C).
The mesh ratio D is, for example, from 0.95 to 1.00, and preferably from 0.98 to 1.00.

(4) The aperture ratio O of the support material layer is expressed as a ratio (usually expressed in%) of a regular polygonal opening when the two-dimensional plane is completely filled (with respect to the surface area of the entire support material layer). However, when a value is substituted into a mathematical expression described later, a ratio value of 0 to 1 is used. The aperture ratio O is determined according to the shape of the opening of the support material layer. When the support material layer has an opening of a regular triangle, the opening ratio is O (A). When the support material layer has a square opening, the opening is O. When the ratio is O (B) and the support material layer has a regular hexagonal opening, the opening ratio may be indicated as O (C). The aperture ratio O is expressed as follows using the side length Q and the wire diameter w or using the mesh ratio D, respectively.

O (A) = (Q- 3 1/2 w) (3 1/2 Q-3w) / (3 1/2 Q 2) = (4-2 · 3 1/2) + (2 · 3 1 / ^{2 -6) D (A) +} 3D (A) 2 ... (B)
O (B) = (Q−w) ² / Q ² = D (B) ² (C)
^{O (C) = (3 1/2} Q-w) 2 / (3Q 2) = (1/3) {(4-2 · 3 1/2) + (2 · 3 1/2 -2) D ( C) + D (C) ² … (D)

開口 From the viewpoint of EUV transmittance, the aperture ratio of the support material layer is preferably 80% or more, more preferably 90% or more, further preferably 98% or more, and preferably 99.9% or less.

The carbon film and the support material layer are preferably a carbonaceous film or a graphite film, more preferably a graphite film, and still more preferably a single graphite film.
The carbon film and the support material layer are preferably formed integrally, without interposing an adhesive layer (for example, a layer formed of an adhesive) or a bonding layer (for example, a layer formed of a metal (eg, nickel)) ( More preferably, they are formed (seamless). According to such a carbon film and a support material layer, the step of forming an adhesive layer or a bonding layer can be omitted, the thickness of the pellicle film can be reduced, outgassing can be suppressed, and the pellicle The strength of the film can be increased.
The ratio of the thickness of the carbon film to the thickness of the support material layer is, for example, 0.001 to 1, preferably 0.01 to 0.7, and more preferably 0.1 to 0.7 from the viewpoint of the strength of the pellicle film and the EUV transmittance. 05 to 0.5, more preferably 0.1 to 0.3.

Hereinafter, a reinforced pellicle film and a method for manufacturing the reinforced pellicle film of the present invention will be described with reference to the illustrated examples.
FIG. 1 is a schematic flow chart of a method for manufacturing a reinforced pellicle film according to the present invention. A pellicle film 10 includes a pellicle film 1a ′ or 1b composed of a carbon film (A) and one or both surfaces of the pellicle film. And a support material layer (B) 4 having a plurality of openings 5 formed therein.
In this specification, a carbon film (pellicle film) 1a 'indicates a carbon film etched on one side, and a carbon film (pellicle film) 1b indicates a carbon film etched on both sides, as described later.

In the reinforced pellicle film 10 of the illustrated example, the carbon film 1a 'or 1b and the support material layer 4 are made of the same carbon material.
That is, the carbon film 1a 'or 1b and the support material layer 4 are preferably a carbonaceous film or a graphite film, and more preferably a graphite film. The carbonaceous film or graphite film is manufactured as described above.
The support material layer 4 exists on one or both sides of the carbon film (pellicle film) 1a 'or 1b, and has a plurality of predetermined openings 5.
In the reinforcing pellicle film 10 of the present invention, the adhesive layer may not be included between the carbon film 1a 'or 1b and the support material layer 4, and the carbon film 1a' or 1b and the support material layer 4 are integrally formed. Is preferred.
When the carbon film 1a 'or 1b and the support material layer 4 are integrated, the peel strength between them can be maintained at a predetermined level or more without using a commonly used adhesive. Further, it is possible to prevent a decrease in durability and outgas generation due to the adhesive.

The thickness t of the 'carbon film 1a' or 1b and the thickness of the support material layer 4 are as described above in the term column. The thickness of the pellicle film may be the same as the thickness of the carbon film 1a 'or 1b. Further, the thickness of the carbon film 1a 'may be larger than the thickness of the carbon film 1b. The shape and thickness of the opening 5 are as described above.

The surface roughness of the carbon film 4 is as described above in the term column. Here, the surface roughness means the roughness on the outer surface side (the side opposite to the contact surface with the support material layer 4) of the carbon film 1a 'or 1b.
The bonding strength between the carbon film 1a 'or 1b and the support material layer 4 only needs to be strong enough not to peel off when the reinforcing pellicle film 10 is manufactured or used. The strength is preferably such that material destruction (for example, material destruction of the carbon film 1a 'or 1b) occurs earlier than interface destruction when a peeling test is performed.

The reinforcing pellicle membrane of the present invention includes, for example, one having a plurality of square (preferably square) openings in the support material layer (FIG. 3), one having a plurality of hexagonal openings in the support material layer (FIG. 4), The support material layer has a plurality of circular openings (FIG. 5), but is not limited thereto.

FIG. 2 shows the carbon film 1b, the support material layer 4, and the opening 5 in the reinforcing pellicle film, the opening, the opening (size) L of the opening, the period P of the opening, and the projections forming the opening. The line width w1 and the line thickness w2 when the portion is rectangular are shown.

The aperture (size) L of the opening, the period P of the opening, and the line width w1 and the line thickness w2 when the convex portion forming the opening is rectangular are as described above.
In particular, since the line thickness w2 can be set to 400 nm or less, both the strength of the pellicle film and the EUV transmittance can be improved.

Ｅ The EUV transmittance of the reinforced pellicle film is, for example, 39 to 94%, preferably 67 to 94%, and more preferably 80 to 94% when the exposure wavelength is 13.5 nm.

(7) Method of Manufacturing Reinforced Pellicle Film In the reinforced pellicle film of the present invention, a mask portion for forming a support material layer is formed in a carbon film thicker than the pellicle film, and the carbon film is etched from at least the mask portion forming surface. , A carbon film and a support material layer made of the same material as the carbon film.
The mask portion is a portion formed on the carbon film in order to form the support material layer by etching, and may be a portion that is removed by etching (also referred to as a first coating layer), and may be removed after etching. (Also referred to as a second coating layer).

The method for manufacturing the reinforcing pellicle film of the present invention may be divided into the following two methods according to the material of the mask portion, the forming method, and the like.
(1) A first coating layer is laminated on a carbon film in a portion except for a portion corresponding to a line width and a shape of a support material layer, and a second coating layer is further laminated on both the first coating layer and the carbon film. The first coating layer and the second coating layer laminated on the first coating layer are both removed, and the second coating layer corresponding to the line width and shape of the support material layer and laminated on the carbon film is used as a mask portion. Method (2) A method in which a first coating layer corresponding to the line width and shape of the support material layer is laminated on the carbon film, and the first coating layer is used as a mask portion as it is. The pattern shape of the support material layer is formed with higher precision. From the viewpoint of the above, the method (1) is preferable.

Hereinafter, a method of manufacturing the reinforced pellicle film in the case of the above (1) will be described.
In one embodiment of the present invention, a step of forming a first coating layer having a predetermined opening pattern on a carbon film thicker than a pellicle film, and a step of laminating a second coating layer on each of the carbon film and the first coating layer Removing both the first coating layer and the second coating layer laminated on the first coating layer from the carbon film while leaving the second coating layer laminated on the carbon film, carbon from the second coating layer forming surface side A pellicle comprising a carbon film, comprising: a step of starting etching for removing the film in the thickness direction, a step of terminating the etching after the support material layer is exposed from the carbon film, and a step of removing the second coating layer. A method for producing a reinforced pellicle membrane, wherein the membrane and a support material layer having a plurality of openings formed on one or both sides of the pellicle membrane are made of the same carbon material is included.

The method includes forming a second coating layer on the carbon film, etching the carbon film from the uneven surface of the second coating layer, exposing the support material layer from the carbon film while leaving the second coating layer, In this method, the pellicle film and the support material layer are integrally formed from the carbon film by removing the coating layer.

The first coating layer is preferably made of a resist from the viewpoint of being easily removed after the formation of the second coating layer, and is more preferably made of a positive photoresist or a negative photoresist.
The shape pattern of the first coating layer may be such that the second coating layer is laminated on the opening, and the second coating layer has the line width and shape of the support material layer.

The second coating layer is preferably made of a metal, and more preferably made of aluminum, from the viewpoint of adjusting the etching strength. The second coating layer may be formed by vapor deposition, sputtering, or the like.
When the second coating layer is formed, a portion where the second coating layer is stacked and a portion where the first coating layer and the second coating layer are stacked exist on the carbon film.

Both the first coating layer and the second coating layer laminated on the first coating layer can be removed by using ordinary means for removing a resist (for example, an alkaline solution or an ozone solution).
The etching is preferably performed on one surface (for example, the surface on which the second coating layer is formed) or both surfaces (for example, the surface on which the second coating layer is formed and the surface on which the second coating layer is not formed) of the carbon film. From the viewpoint of adjustment, it is more preferable that the adjustment is performed on both surfaces of the carbon film.
After the etching, the second coating layer is preferably removed with an acid (preferably, an inorganic acid such as hydrochloric acid, sulfuric acid, and nitric acid) from the viewpoint of preventing damage to the reinforcing pellicle film during heating.

The projections forming the second coating layer preferably correspond to the projections forming the opening of the support material layer after etching, and the recesses forming the second coating layer preferably correspond to the opening of the support material layer after etching. It is preferable to correspond to the concave portion constituting the portion. The bottom surface of the concave portion may be a surface portion of a carbon film (pellicle film).
By doing so, the reinforcing pellicle film including the pellicle film composed of the carbon film (A) and the support material layer (B) having a plurality of openings formed on one or both surfaces of the pellicle film is obtained. Can be formed. Further, the pellicle film and the support material layer can be integrally formed.

Next, a method of manufacturing the reinforced pellicle film in the case of the above (2) will be described.
In another aspect of the present invention, a step of forming a coating layer having a predetermined opening pattern on a carbon film thicker than a pellicle film, removing both the coating layer and the carbon film in the thickness direction from the coating layer forming surface side A step of initiating the etching, and a step of terminating the etching after at least the carbon film under the coating layer is exposed, and a pellicle film composed of a carbon film and a plurality of openings formed on one or both surfaces of the pellicle film The method for producing a reinforced pellicle membrane, wherein the support material layer having the portion is made of the same carbon material, is included.

In the production method of the present invention, an uneven shape is formed by a coating layer on a carbon film, and etching is performed from the formed uneven surface, until the coating layer is removed, or a part of the coating layer and the carbon film are removed. Until the carbon film is exposed, and the pellicle film and the support material layer are simultaneously formed from the carbon film. The protrusions forming the covering layer preferably correspond to the protrusions forming the opening of the support material layer after etching, and the recesses forming the coating layer form the openings of the support material layer after etching. Preferably, it corresponds to the recess. The bottom surface of the concave portion may be a surface portion of a carbon film (pellicle film).
By doing so, the reinforcing pellicle film including the pellicle film composed of the carbon film (A) and the support material layer (B) having a plurality of openings formed on one or both surfaces of the pellicle film is obtained. Can be formed. Further, the pellicle film and the support material layer can be integrally formed without the interposition of an adhesive layer or a bonding layer.

FIGS. 1 (a), (b), (c1), (d), (e1), (e2), (f1), and (2) are schematic flow charts for explaining a method for producing a reinforced pellicle membrane of the present invention. (F2)). This flowchart corresponds to the method of manufacturing the reinforced pellicle film in the case of the above (1).
First, a step of forming a first coating layer having a predetermined opening pattern on a carbon film thicker than a pellicle film will be described with reference to FIGS. 1 (a) to (c1).

In FIG. 1A, a predetermined carbon film 1a serving as a material of a reinforcing pellicle film is manufactured. As the carbon film raw material, a known carbonized raw material can be used, and the above-described aromatic polyimide is preferably used.
The carbonaceous film is obtained by heating the carbon film material at a carbonization temperature (for example, about 900 to 2000 ° C. in the case of an aromatic polyimide).
Next, the obtained carbonaceous film is treated at a graphitization temperature (for example, higher than 2000 ° C. and 3300 ° C. or lower) to obtain a graphite film.
This graphite film can also be directly produced by treating a carbon film raw material at a graphitization temperature.
Note that, depending on the type of the carbon film, it can be directly formed by a vapor deposition method or a sputtering method. The thickness of the carbon film 1a may be larger than the thickness of the etched carbon film 1a 'or 1b, and is, for example, 500 nm to 5 μm, preferably 700 nm to 3 μm, and more preferably 900 nm to 1.5 μm.

In FIG. 1B, a first coating layer 2a is laminated on one side surface of the obtained carbon film 1a to produce a laminate A.
The first coating layer 2a may be a layer formed by applying a resist, or may be a resin layer or the like suitable for imprint.
The first coating layer 2a is preferably a photoresist layer from the viewpoint of forming an uneven shape by a simple operation.
The photoresist may be either a positive photoresist or a negative photoresist.
The thickness of the first coating layer 2a is, for example, 1 to 12 μm, preferably 2 to 9 μm, and more preferably 3 to 6 μm.

In FIG. 1 (c1), a first coating layer 2b having a predetermined pattern is formed from the first coating layer 2a to obtain a laminate B of the carbon film 1a and the first coating layer 2b. The opening of the first coating layer 2b is composed of a convex portion and a concave portion, and the concave portion may be a portion for forming the second coating layer 3.
For the exposure, dissolution, and washing of the photoresist, conventionally known methods can be employed.

The pattern shape of the first coating layer 2b may be reverse to the pattern shape of the support material layer having a plurality of openings after etching, as described later.
The thickness of the first coating layer 2b may be the same as the thickness of the first coating layer 2a.
When the individual protrusions forming the first coating layer 2b are square, the line width of the protrusions is, for example, 0.5 to 10 μm, preferably 1 to 7 μm, and more preferably 2 to 5 μm.
When the individual protrusions forming the first coating layer 2b are quadrangular, the period of the protrusions (the length between the start of the protrusion and the start of the adjacent protrusion) is, for example, 10 to 5000 μm, and more preferably 50 to 5000 μm. ～ 4000 μm, more preferably 100-3000 μm.

With respect to the laminate B obtained in FIG. 1 (c1), the second coating layer 3 is laminated on each of the carbon film 1a and the first coating layer 2b to produce a laminate C (FIG. 1 (d)).
The second coating layer 3 may be any layer that can function as a layer that controls etching, and is preferably made of a metal, and more preferably made of aluminum.
The second coating layer 3 may be laminated by vapor deposition (preferably, vacuum vapor deposition). The second coating layer 3 is preferably stacked over the entire irregularities of the carbon film and the first coating layer 2b stacked on the carbon film. The thickness of the second coating layer 3 is, for example, 0.5 to 50 nm. Preferably it is 1 to 30 nm, more preferably 1 to 10 nm. The line width of the second coating layer 3 is, for example, 0.5 to 10 μm, preferably 1 to 7 μm, and more preferably 2 to 5 μm.

With respect to the laminate C obtained in FIG. 1D, the second coating layer 3 laminated on the first coating layer 2b and the first coating layer 2b while leaving the second coating layer 3 laminated on the carbon film 1a. Both are removed from the carbon film 1a to obtain a laminate D (FIG. 1 (e1)).
In this step, means for removing the resist of the first coating layer may be performed, and it is preferable to apply a solution for removing the resist (for example, an alkaline solution or an ozone solution) to the laminate C.

In the method, a portion where the first coating layer 2b exists (also referred to as a convex portion forming the first coating layer 2b) corresponds to a concave portion forming the opening 5 of the support material layer 4 after the etching (the concave portion). May be the surface portion (exposed portion) of the etched carbon film (pellicle film) 1a 'or 1b) or a portion where the first coating layer 2b does not exist (also referred to as a concave portion forming the first coating layer 2b). ) May be a portion where the second coating layer 3 is laminated on the carbon film 1a, and may correspond to a convex portion forming the opening 5 of the support material layer 4 after etching. In addition, the portion where the second coating layer 3 exists (the convex portion forming the second coating layer 3) and the portion where the second coating layer 3 does not exist (the concave portion forming the second coating layer 3) are formed of carbon before etching. Preferably, it is present over the entire film 1a.

Next, etching for removing the carbon film 1a in the thickness direction from the second coating layer forming surface side of the laminate D is started (FIG. 1 (e2)).
By this etching, the support material layer 4 made of the same material as the carbon film 1a is formed while leaving the second coating layer 3, and the carbon film 1a 'having the support material layer 4 and the opening 5 is formed. Body E).

In the etching, a part of the carbon film 1a (preferably at least 20%, more preferably at least 40%, still more preferably at least 60%, even more preferably at least part of the carbon film thickness from the second coating layer forming surface side) (80% or more) in the thickness direction to remove the support material layer 4.

The etching may be wet etching or dry etching, and is preferably dry etching from the viewpoint of controlling a more precise pattern. For dry etching, conventionally known conditions can be adopted.
The temperature is, for example, 0 ° C to 40 ° C, preferably 10 ° C to 30 ° C.
The gas pressure is, for example, 1 to 100 Pa, preferably 10 to 50 Pa.
The etching gas is, for example, O ₂ , H ₂ , N ₂ , Ar, CF ₄ , Cl ₂ , H ₂ O, or the like. Further, it may be a mixed gas.
The flow rate of the etching gas is, for example, 5 to 1000 sccm, preferably 10 to 700 sccm.
The etching time is, for example, 0.1 to 10 hours, preferably 0.2 to 5 hours.
As the etching apparatus, for example, a reactive ion etching apparatus (RIE-10NR manufactured by Samco) can be used.

The etching is preferably performed on one surface (for example, the surface on which the second coating layer is formed) or both surfaces (the surface on which the second coating layer is formed and the surface on which the second coating layer is not formed) of the carbon film 1a. When one surface of the carbon film 1a is etched, the surface on which the second coating layer 3 is formed may be etched.
When etching both surfaces of the carbon film 1a, the etching from the surface on which the second coating layer 3 is not formed may be performed before or after removing the second coating layer 3 described later. It is preferable that the carbon film 1a 'having one surface etched is etched from the surface on which the second coating layer 3 is not formed to form a carbon film 1b (FIG. 1 (f2)). By etching both surfaces of the carbon film, it is possible to appropriately adjust the thickness of the carbon film 1b from the viewpoint of EUV transmittance.

For the laminate E, the second coating layer 3 is removed from the support material layer 4 (FIG. 1 (f1)).
The second coating layer 3 is preferably removed with an acid from the viewpoint of preventing damage to the reinforcing pellicle film during heating, and the acid is preferably an inorganic acid such as hydrochloric acid, sulfuric acid, and nitric acid.
The concentration of the acid is, for example, 0.1 to 30% by mass, preferably 1 to 20% by mass in 100% by mass of the acid solution.

FIG. 1 (a), (b), (c2), (f1), and (f2)) are schematic flow charts for explaining a method for producing a reinforced pellicle film of the present invention. The flowchart corresponds to the method for manufacturing a reinforced pellicle film in the case of the above (2). First, a step of forming a coating layer having a predetermined opening pattern on a carbon film thicker than a pellicle film will be described with reference to FIGS. 1 (a) to (c2).

1A and 1B are as described above. In FIG. 1 (c2), the first coating layer 2b is formed by laminating a first coating layer 2b having a predetermined pattern on the carbon film 1a so that the support material layer after etching has a predetermined opening. A laminate F is obtained.
The material of the first coating layer 2a is the same as described above. As described above, the pattern shape may be formed by appropriately exposing, dissolving, and washing the photoresist.

The pattern shape of the first coating layer 2b only needs to correspond to the pattern shape of the carbon material and the support material layer having a plurality of openings after etching, which will be described later.
The thickness of the first coating layer 2b may be the same as the thickness of the first coating layer 2a.
When the individual protrusions forming the first coating layer 2b are square, the line width of the protrusions is, for example, 0.5 to 10 μm, preferably 1 to 7 μm, and more preferably 2 to 5 μm.
When the individual protrusions forming the first coating layer 2b are quadrangular, the period of the protrusions (the length between the start of the protrusion and the start of the adjacent protrusion) is, for example, 10 to 5000 μm, and more preferably 50 to 5000 μm. ～ 4000 μm, more preferably 100-3000 μm.

In this method, the positional relationship between the first coating layer 2b before the etching and the support material layer 4 or the carbon film 1a 'or 1b after the etching is as follows.
For example, a portion where the first coating layer 2b exists (also referred to as a convex portion forming the first coating layer 2b) corresponds to a convex portion forming the opening 5 of the support material layer 4 after the etching, and The portion where the layer 2b does not exist (also referred to as the concave portion forming the first coating layer 2b) may correspond to the concave portion forming the opening 5 of the support material layer 4 after the etching (the concave portion is a portion after the etching). It may be a surface portion (exposed portion) of the carbon film (pellicle film) 1a 'or 1b). In addition, the portion where the first coating layer 2b exists (the convex portion forming the first coating layer 2b) and the portion where the first coating layer 2b does not exist (the concave portion forming the first coating layer 2b) are formed of carbon before etching. Preferably, it is present over the entire film 1a.

(4) Next, etching is started to remove both the first coating layer and the carbon film in the thickness direction from the first coating layer forming surface side (FIG. 1 (f1)).

The etching is preferably performed so as to remove both the first coating layer 2b and the carbon film 1a in the thickness direction from the first coating layer forming surface side, and the first coating layer 2b from the first coating layer forming surface side. More preferably, the first coating layer 2b is completely removed in the thickness direction from the first coating layer forming surface side, and a part of the carbon film 1a is removed in the thickness direction. Is more preferred. Etching conditions may be the same as described above.

Further, after at least the carbon film under the first coating layer is exposed, the etching is terminated.
The etching is preferably performed at least until the carbon film 1a under the first coating layer 2b is exposed. In this case, the projections forming the first coating layer 2b are formed in the openings 5 of the support material layer 4. The concave portion forming the first covering layer 2b may be a concave portion forming the opening 5 of the support material layer 4 (the concave portion may be a surface portion (exposed portion) of the carbon film 1a 'or 1b. )).

The etching is preferably performed on one side or both sides of the carbon film 1a. When one side of the carbon film 1a is etched, the surface on which the first coating layer 2b is formed may be etched.
When etching both surfaces of the carbon film 1a, the thickness of the carbon film 1b can be appropriately adjusted from the viewpoint of EUV transmittance.

Regarding the laminate F obtained in FIG. 1 (c2), the laminate G may be produced by laminating the second coating layer 3 on the first coating layer 2b (not shown).
That is, the manufacturing method preferably further includes a step of laminating the second coating layer 3 before etching. Such a step is preferably performed so that etching can be appropriately adjusted and a desired pattern shape is formed.
The second coating layer 3 may be any layer that can function as a layer that controls etching, and is preferably made of a metal, and more preferably made of aluminum.
The second coating layer 3 may be laminated by vapor deposition (preferably, vacuum vapor deposition). The second coating layer 3 is preferably laminated on the entire uneven shape of the carbon film 1a and the first coating layer 2b, and the thickness of the second coating layer 3 is, for example, 0.5 to 50 nm, preferably 1 to 30 nm. , More preferably 1 to 10 nm.

The molded body obtained by etching the laminate F obtained in FIG. 1 (c2) becomes the reinforcing pellicle film of the present invention. On the other hand, the reinforced pellicle film of the present invention can be formed by removing the second coating layer (preferably a metal layer) from the laminate H obtained by etching the laminate G.
That is, the manufacturing method preferably further includes a step of removing the second coating layer (preferably a metal layer) with an acid after the etching. The acid and the concentration of the acid are as described above.

As described above, the reinforced pellicle film of the present invention can be produced.
The thickness of the carbon film 1a 'or 1b (for example, the thickness of the carbon film 1a' or 1b after etching) is preferably smaller than the thickness of the carbon film 1a (for example, the thickness of the carbon film 1a before etching). The thickness is more preferably 10 times smaller than the thickness of the carbon film 1a, and further preferably 50 times smaller than the thickness of the carbon film 1a.

The thickness of the support material layer 4 is preferably as described above. The thickness of the opening 5 is preferably the same as the thickness of the support material layer 4.
The combined thickness of the carbon film 1a 'or 1b and the thickness of the support material layer 4 is preferably the same as or smaller than the thickness of the carbon film 1a. It is preferable that all the support material layers 4 are made of the carbon film 1a.

According to the manufacturing method of the present invention, a pellicle film composed of a carbon film made of the same carbon material and a support material layer can be integrally formed, and a pattern having a desired opening is formed on the support material layer. Since the thickness of the support material layer and the opening can be reduced, it is possible to achieve both the strength of the pellicle film and the EUV transmittance. Furthermore, since the carbon film and the support material layer are made of the same carbon material and can be a reinforced pellicle film having almost no difference in linear expansion coefficient, breakage or peeling does not occur even during heating.

This application claims the benefit of priority based on Japanese Patent Application No. 2018-129345 filed on July 6, 2018. The entire content of the specification of Japanese Patent Application No. 2018-129345 filed on July 6, 2018 is incorporated herein by reference.

Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by the following examples, and it is a matter of course that the present invention can be carried out with appropriate modifications within a range that can be adapted to the spirit of the present invention described below. Included in the scope.

補強 The reinforced pellicle film obtained in the following examples was measured by the following method.

<Method for measuring thickness of carbon film (pellicle film)>
The thickness (t in FIG. 2) of the carbon film (pellicle film) was determined by a cross-sectional TEM using a cross section perpendicular to the film direction of the carbon film (pellicle film).

<Measurement method of support material layer>
As shown in FIG. 2, the line width w1, the line thickness w2, and the side length Q (period P) of the support material layer were determined by surface measurement using a laser microscope.

<Surface roughness (Sa)>
In the present invention, the surface roughness (Sa) of the surface side of the pellicle film (the surface without the support material layer) was measured with a laser microscope and calculated based on ISO 25178. The magnification of the laser microscope was 50 times, and the cutoff value (λc) was 80 μm. The measurement position of the surface roughness (Sa) is not particularly limited, but a plurality of positions including one central portion and four end portions were measured, and the average was defined as the surface roughness (Sa).

<EUV transmittance>
The relationship between the EUV transmittance (T) and the thickness of the graphite thin film is expressed by the following formula using the transmittance of single-layer graphene of 13.5 nm (0.998) and the thickness of single-layer graphene (0.3354 nm). Is shown.
Film thickness (nm) = Log _0.998 (T [%] / 100) × 0.3354

<Heat resistance test>
The reinforced pellicle film was held at 500 ° C., 1000 ° C., and 1500 ° C. for 10 minutes under vacuum conditions, and it was confirmed by a laser microscope and appearance inspection whether or not the support material layer had changed.

(Production Example 1-1: Preparation of polyimide film)
A 17.5% by mass dimethylformamide solution of polyamic acid prepared by mixing pyromellitic dianhydride, 4,4′-diaminodiphenyl ether and p-phenylenediamine at a molar ratio of 2: 1: 1 was synthesized. Using a coater, the solution was cast-coated on a glass substrate having a diameter of 30 cm, heated at 120 ° C. for 30 minutes, heated at 250 ° C. and 450 ° C. for 10 minutes each, cooled, and then separated from the substrate to form a polyimide film. The thickness of the obtained polyimide film was 3 μm.

(Production Example 2-1: Production of Graphite Film)
The polyimide film having a thickness of 3 μm obtained in Production Example 1-1 was sandwiched between graphite plates, and heated to 950 ° C. at a rate of 5 ° C./min in a nitrogen gas atmosphere using an electric furnace. After holding for 20 minutes, the mixture was naturally cooled to obtain a carbonaceous film. The obtained carbonaceous film was heated at a rate of 5 ° C./min to 2800 ° C. in an argon gas atmosphere at a rate of 5 ° C./min, and kept at 2800 ° C. for 20 minutes while placing a weight on the end of the film. Natural cooling was performed to obtain a graphite film (carbon film 1a). The thickness of the graphite film was 1 μm, and the surface of the film was mirror-like.

(Production Example 3-1: Preparation of Reinforced Pellicle Membrane in Which Carbon Film and Supporting Material Layer are Made of Same Carbon Material)
A g-line positive type photoresist (OFPR-800LB manufactured by Tokyo Ohka Co., Ltd.) is applied as a first coating layer to a graphite film (carbon film 1a) cut into a 10 cm square (FIG. 1B), and a mask aligner (Mikasa Corporation) (MA-60F), a pattern (lattice pattern, opening 5 is a square) with a period P = 3000 μm, a line width w1 = 3 μm, and a line thickness w2 = 5 μm is exposed, and a heat treatment for solvent removal is performed. After performing, rinsing with development / pure water and drying were performed, and the first coating layer of the portion exposed to the pattern was removed to obtain a graphite film in which the first coating layer of the unexposed portion remained. (FIG. 1 (c)). An aluminum layer having a line width of 3 μm and a film thickness of 5 nm was formed as a second coating layer by vacuum evaporation from the surface on which the first coating layer was formed on the entire graphite film on which the first coating layer in the unexposed portion remained (FIG. 1 ( d)). The aluminum layer in direct contact with the graphite film (carbon film 1a) serves as a mask in the next dry etching step. Thereafter, using a resist removing solution, the photoresist and the aluminum layer covering the photoresist were removed, leaving only the aluminum layer directly formed on the graphite film (carbon film 1a) (FIG. 1 (e1)). ).

Thereafter, dry etching was performed from the surface on which the second coating layer was formed using a reactive ion etching apparatus (RIE-10NR manufactured by Samco). Under the conditions of an RF output of 50 W, a process gas (oxygen gas) flow rate of 100 sccm, a gas pressure of 10 Pa, and a processing time of 9 minutes, a pattern with a period P = 3000 μm and a line width w1 = 3 μm (a lattice pattern, the opening 5 is a square). Then, a line thickness w2 of 50 nm was formed, and the support material layer 4 and the opening 5 were formed on the carbon film 1a '(FIG. 1 (e2)). Thereafter, the aluminum layer was removed using 10% hydrochloric acid (FIG. 1 (f1)). This laminate was turned upside down and dry-etched from the side where the support material layer was not formed under the conditions of an RF output of 100 W, a process gas (oxygen gas) flow rate of 100 sccm, a gas pressure of 20 Pa, and a processing time of 28.5 minutes (FIG. )), The carbon film 1b (pellicle film), which is a graphite film, has a thickness of 10 nm, the support material layer 4 is made of a graphite film, the openings 5 are formed in a grid pattern, the openings 5 are square, the period P = 3000 μm, and the line is A reinforced pellicle membrane having a width w1 = 3 μm, a line thickness w2 = 50 nm, an aperture L = 2997 μm, and a mesh ratio D (B) of 0.999 was produced. The thickness of the carbon film (pellicle film) was measured by a cross-sectional TEM, and the period P, line width w1, and line thickness w2 of the support material layer were measured by a laser microscope. The aperture ratio of this reinforced pellicle film was 99.8%. Sa was 90 nm. The EUV transmittance was determined to be 55% from the thickness of the carbon film 1b. Further, even after the heat resistance test at 500 ° C., 1000 ° C., and 1500 ° C., no change was observed in the structure of the reinforcing pellicle film, and no damage was observed.

(Production Example 3-2: Production of Reinforced Pellicle Film in Which Carbon Film and Supporting Material Layer are Made of Different Materials)
A g-line positive type photoresist (OFPR-800LB manufactured by Tokyo Ohka Co., Ltd.) is applied as a first coating layer to a graphite film cut into a square of 10 cm, and a period P = is applied using a mask aligner (MA-60F manufactured by Mikasa). After exposing a pattern (lattice pattern, opening is a regular square) of 3000 μm, line width w1 = 3 μm, and line thickness w2 = 5 μm, and performing a heat treatment for solvent removal, development, rinsing with pure water and drying. . An aluminum layer having a thickness of 5 nm was formed as a second coating layer on the laminate of the graphite film and the first coating layer by vacuum deposition from the surface on which the first coating layer was formed. Thereafter, the photoresist and the aluminum layer coated with the photoresist were removed using a resist removing solution, leaving only the aluminum layer directly formed on the graphite film (carbon film 1a) (FIG. 1 (e1)).

(5) Thereafter, the laminate was turned over and dry-etched using a reactive ion etching apparatus (RIE-10NR manufactured by Samco). A dry etching process is performed from the side where the second coating layer is not formed under the conditions of an RF output of 100 W, a flow rate of a process gas (oxygen gas) of 100 sccm, a gas pressure of 20 Pa, and a processing time of 28.5 minutes, and a carbon film (pellicle film) which is a graphite film ) Has a thickness of 10 nm, the support material layer is made of aluminum, the opening is a square in a lattice pattern, the period P = 3000 μm, the line width w1 = 3 μm, and the line thickness w2 = 50 nm. Produced. The thickness of the carbon film (pellicle film) was measured by a cross-sectional TEM, and the period P, line width w1, and line thickness w2 of the support material layer were measured by a laser microscope. The aperture ratio of this reinforced pellicle film was 99.8%. Sa was 90 nm. From the thickness of the carbon film 1b, the EUV transmittance was determined to be 94%.

In the heat resistance test at 500 ° C. of the reinforced pellicle film, the support material layer was partially melted or peeled off, and the difference in the coefficient of thermal expansion between the graphite film and the aluminum contained in the support material layer was considered to be a problem. Was done. Furthermore, in the heat resistance test at 1000 ° C. and 1500 ° C., the aluminum layer contained in the support material layer was completely lost, and a part of the graphite was broken.

The reinforcing pellicle film of the present invention is useful for protecting a photomask used in various lithography methods such as an EUV lithography method.

10, 20, 30, 40, 50: reinforcing pellicle film 1a: carbon film (carbon film before etching)
1a ′: carbon film (carbon film, pellicle film on which support material layer (made of the same material as carbon film) is formed after one-sided etching)
1b: carbon film (carbon film, pellicle film on which support material layer (made of the same material as carbon film) is formed after both-side etching)
2a, 2b: first coating layer 3: second coating layer (metal layer)
4: Support material layer 5: Opening t: Carbon film thickness L: Aperture w1: Line width P: Period w2: Line thickness

Claims (11)

1. A pellicle film composed of a carbon film, and a support material layer having a plurality of openings formed on one or both surfaces of the pellicle film, wherein the pellicle film and the support material layer are made of the same carbon material. Characterized reinforced pellicle membrane.
2. The reinforcing pellicle film according to claim 1, wherein the carbon film and the support material layer are carbonaceous films or graphite films.
3. The reinforcing pellicle film according to claim 1 or 2, wherein the carbon film and the support material layer are integrally formed.
4. (4) The reinforced pellicle film according to any one of (1) to (3), wherein the carbon film and the support material layer are formed of the same carbon material without interposing an adhesive layer or a bonding layer.
5. (5) The reinforced pellicle membrane according to any one of (1) to (4), wherein an aperture ratio of the support material layer is 80% or more.
6. (6) The reinforced pellicle film according to any one of (1) to (5), wherein the thickness of the pellicle film is 1 to 100 nm, and the thickness of the support material layer is 1 to 500 nm.
7. A method for producing a reinforced pellicle membrane according to any one of claims 1 to 6, wherein
   Forming a first coating layer having a predetermined opening pattern on a carbon film thicker than the pellicle film,
   A step of laminating a second coating layer on each of the carbon film and the first coating layer,
   Removing both the first coating layer and the second coating layer stacked on the first coating layer from the carbon film while leaving the second coating layer stacked on the carbon film;
   A step of starting etching for removing the carbon film in the thickness direction from the second coating layer forming surface side;
   After the support material layer is exposed from the carbon film, the method includes a step of terminating the etching, and a step of removing the second coating layer, and is formed on one or both surfaces of the pellicle film composed of the carbon film and the pellicle film. A method for manufacturing a reinforced pellicle membrane, wherein the support material layer having a plurality of openings is made of the same carbon material.
8. 8. The method according to claim 7, wherein the etching is performed on one side or both sides of the carbon film.
9. 9. The method according to claim 7, wherein the first coating layer is made of a resist, and the second coating layer is made of a metal.
10. (10) The method according to any one of (7) to (9), wherein the second coating layer is removed with an acid after the etching.
11. The method according to any one of claims 7 to 10, wherein the second coating layer is made of aluminum.
    

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