Film and mask including the same

Abstract

The present invention relates to a pellicle and a mask including the same. A pellicle to be used in a photolithography process is provided. The pellicle includes a film, at least a portion of which includes a carbon allotrope. The film has a first surface and a second surface opposite to the first surface, the film includes a doped region containing a dopant, the doped region is adjacent to the first surface, the dopant includes at least one of boron or nitrogen, and the doped region includes bonds between atoms of at least one of the dopant and carbon atoms.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the priority of Korean Patent Application No. 10-2018-0014337 filed in the Korean Intellectual Property Office on February 6, 2018, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The inventive concept relates to a pellicle for a photolithography process and a reticle including the same. Background Art

[0004] A pellicle is a thin film disposed on a photomask to help protect the photomask from external contaminating materials such as dust or resist (photoresist). A pellicle can be prepared to have high transmittance to the light used in the photolithography process and meet a variety of other technical requirements such as heat dissipation, strength, durability and / or stability characteristics. The material used for the pellicle is selected in consideration of the wavelength of the light used in the photolithography process. However, the wavelength of light used in the photolithography process is gradually reduced to meet the demand or desire for semiconductor devices with reduced line widths, and such a reduction in wavelength causes a change in the material used for the pellicle. Summary of the invention

[0005] Some example embodiments of the present inventive concepts provide a surface film having high optical transmittance and / or high chemical and mechanical durability.

[0006] Some example embodiments of the present inventive concepts provide a reticle including a highly durable pellicle.

[0007] According to some example embodiments of the present inventive concepts, a pellicle may include a film, at least a portion of which includes a carbon allotrope, the film having a first surface and a second surface opposite to the first surface, the film including a doped region including a dopant (a plurality of dopants), the doped region being adjacent to the first surface, the dopant including at least one of boron or nitrogen, and the doped region including bonds between atoms of at least one of the dopants and carbon atoms.

[0008] According to some example embodiments of the present inventive concepts, a pellicle may include a film, at least a portion of which includes one of the carbon allotropes, the film having a first surface and a second surface opposite to the first surface, the film including a doped region including a dopant (a plurality of dopants), the doped region being adjacent to the first surface, the dopant including boron, and a concentration of boron in the doped region increasing from the first surface to a midpoint of the doped region and decreasing from the midpoint to the second surface.

[0009] According to some example embodiments of the inventive concept, a mask may include: a photomask including a mask substrate and a mask pattern on the mask substrate; a pellicle including a first surface and a second surface opposite to the first surface, the first surface being exposed to the outside and the second surface facing the photomask; and a frame between the photomask and the pellicle. The pellicle includes a film at least a portion of which includes a carbon allotrope (a plurality of carbon allotrope), the pellicle includes a doped region including a dopant (a plurality of dopants), the doped region being adjacent to the first surface, and the dopant including at least one of boron or nitrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Example embodiments will be more clearly understood from the following brief description taken in conjunction with the accompanying drawings.The accompanying drawings illustrate non-limiting example embodiments as described herein.

[0011] Figure 1 are cross-sectional views illustrating pellicles according to some example embodiments of the present inventive concepts.

[0012] Figure 2A yes Figure 1 Chemical structure diagram of the atomic layers in the surface film.

[0013] Figure 2B yes Figure 1 Chemical structure diagram of the atomic layers in the doped region of the surface film.

[0014] Figure 3 Yes Display Figure 1 A diagram of the dopant concentration distribution in the doped region of the surface film.

[0015] Figure 4 are cross-sectional views illustrating reticles according to some example embodiments of the inventive concepts.

[0016] Figure 5 and 6 are conceptual diagrams each illustrating an exposure system using a mask according to some example embodiments of the inventive concepts.

[0017] Figure 7 is a conceptual diagram showing a photolithography process using a mask without a pellicle.

[0018] Figure 8 is a conceptual diagram showing a photolithography process using a mask having a pellicle.

[0019] Fig. 9 and 10 are cross-sectional views illustrating a method of manufacturing a reticle according to some example embodiments of the inventive concepts.

[0020] It should be noted that these figures are intended to illustrate the general features of the methods, structures and / or materials used in some example embodiments and are supplementary to the written description provided below. However, these figures are not to scale and may not accurately reflect the precise structure or performance characteristics of any given embodiment, and should not be interpreted as defining or limiting the range of values ​​or properties covered by the example embodiments. For example, for clarity, the relative thickness and position of molecules, layers, regions and / or structural elements may be reduced or enlarged. The use of similar or identical reference numerals in the various drawings is intended to indicate the presence of similar or identical elements or features. DETAILED DESCRIPTION

[0021] Example embodiments of the inventive concepts will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown.

[0022] Figure 1 are cross-sectional views illustrating pellicles according to some example embodiments of the present inventive concepts. Figure 2A yes Figure 1 Chemical structure diagram of the atomic layers in the surface film. Figure 2B yes Figure 1 Chemical structure diagram of the atomic layers in the doped region of the surface film. Figure 3 Yes Display Figure 1 A diagram of the dopant concentration distribution in the doped region of the surface film.

[0023] See also Figure 1 , 2A 2B, the pellicle PEL may be provided in the form of a thin film or membrane MEM. The pellicle PEL or membrane MEM may include a first surface PELa and a second surface PELb facing each other. The pellicle PEL may consist only of the membrane MEM and may have a single-layer structure. In other words, no additional layer (e.g., containing a material different from the membrane MEM) may be provided on the first surface PELa and / or the second surface PELb of the membrane MEM. The first and second surfaces PELa and PELb of the membrane MEM may be exposed to the air. The thickness TI of the membrane MEM may be in the range of about 5 nm to about 100 nm.

[0024] Return to reference Figure 2A , the membrane MEM may be formed of or include a carbon allotrope. In some example embodiments, the membrane MEM may be formed of or include a carbon-containing material (e.g., graphene or graphite) having a two-dimensional atomic structure. The membrane MEM may include a single carbon atom layer or a plurality of stacked carbon atom layers formed of one of the carbon allotropes. For example, the carbon atom layer may be a single carbon atom layer, at least a portion of which is formed of carbon atoms bonded to each other by covalent bonds. In addition, the carbon atoms in the carbon atom layer may be arranged two-dimensionally.

[0025] The membrane MEM may be a single layer or several layers (several layers), at least a portion of which is formed by one of the carbon allotropes. In the case where the membrane MEM is provided in the form of several layers, the membrane MEM may include 2 to 100 carbon atom layers stacked vertically (vertically). For example, the membrane MEM may include or consist of stacked carbon atom layers, each of which has a two-dimensional structure and is vertically (vertically) connected (bonded) to each other by van der Waals attraction. As an example, the surface membrane PEL may be a membrane MEM consisting of a single carbon atom layer or several carbon atom layers.

[0026] Figure 2A The two-dimensional carbon atom layers included in the membrane MEM may each be formed of carbon atoms connected to each other to form a two-dimensional honeycomb structure. In the case where the bonds between the carbon atoms in the atomic layer are broken, hydrogen may be bonded to the carbon atoms. Although not shown, instead of hydrogen, at least one of a hydroxyl group, an epoxy group, a carbonyl group, or a carboxyl group may be bonded to the carbon atoms.

[0027] In some example embodiments, the membrane MEM may be provided to have a three-dimensional structure, at least a portion of which is formed of one of the carbon allotropes. For example, the pellicle PEL or the membrane MEM may be formed of porous carbon, carbon nanowires, carbon nanotubes, or diamond.

[0028] The membrane MEM may include a doped region DR adjacent to the first surface PELa. The doped region DR may be a region of the membrane MEM doped with a dopant. For example, the doped region DR may be formed by injecting, for example, implanting, a dopant into the membrane MEM using an ion implantation process. As an example, a depth DE of the doped region DR in the membrane MEM may be in the range of about 4 nm to about 10 nm when measured from the first surface PELa.

[0029] The dopant may include atoms having a size similar to that of carbon atoms. The dopant may be selected from elements that can replace carbon atoms in the membrane MEM. As an example, at least one of boron (B) or nitrogen (N) may be used as a dopant in the doping region DR. In the case where an element that cannot replace carbon atoms is used as a dopant, it may be difficult to improve the durability of the pellicle PEL and the transmittance of the pellicle PEL to extreme ultraviolet (EUV) light.

[0030] Return to reference Figure 2B, the two-dimensional carbon atom layer included in the membrane MEM may include a dopant (e.g., boron). For example, a boron atom may replace a carbon atom in the membrane MEM to form a BC bond with another carbon atom adjacent thereto. In some example embodiments, a boron atom may be used to replace an adjacent pair of carbon atoms, and in this case, a BB bond may be formed. In the doped region DR, the number of BC bonds may be greater than the number of BB bonds. For example, the ratio of the number of BC bonds to the total number of BC and BB bonds may be about 67%, and the ratio of BB bonds to the total number of BC and BB bonds may be about 33%. At least one of the boron atoms replacing the carbon atom may bond to a hydrogen atom to form a BH bond.

[0031] The doping region DR may be formed to have a doping strength of about 1.0E20 / cm 3 To 1.0E21 / cm 3 In some example embodiments, the atomic percentage of the dopant in the doping region DR may be in the range of about 1 atomic % to about 3 atomic %. Figure 1 and 3 , the dopant concentration of the doping region DR may be the highest at the midpoint MID of the doping region DR. The dopant concentration of the doping region DR may increase in the interval from the first surface PELa to the midpoint MID, and may decrease in the interval from the midpoint MID to the second surface PELb, as shown in FIG. Figure 3 as shown in .

[0032] The depth from the first surface PELa to the midpoint MID may be about half the depth DE of the doping region DR. For example, in the case where the depth DE of the doping region DR is 5 nm, the depth of the midpoint MID may be 2.5 nm.

[0033] According to some example embodiments of the present inventive concept, the pellicle is configured to be transparent to extreme ultraviolet (EUV) light. The pellicle PEL may include or consist of a membrane MEM formed of one of the carbon allotropes and having a thickness ranging from about 5 nm to about 100 nm, and in this case, the pellicle PEL may have a transmittance of about 70% or more to EUV light. Therefore, the pellicle PEL according to some example embodiments of the present inventive concept can be used in an EUV exposure system. In addition, the pellicle PEL according to some example embodiments of the present inventive concept may have high thermal conductivity, good heat dissipation characteristics, high mechanical strength (e.g., high tensile strength) and / or good EUV tolerance characteristics.

[0034] [Experimental Example]

[0035] A 50 nm thick graphite layer is formed on the nickel layer by a CVD deposition process. An ion implantation process is performed on the graphite layer to implant boron into the graphite layer. In the ion implantation process, the ion acceleration energy is 500 eV and the boron dose is adjusted to 6.0E14 / cm 2 The surface film according to the experimental embodiment was prepared by separating a graphite layer from a nickel layer.

[0036] When EUV light emitted from an EUV system is irradiated on the prepared pellicle, the pellicle has a transmittance of about 70% to EUV light. According to XPS analysis performed on the pellicle, the boron doped in the graphite layer has an atomic percentage of 1.24 atomic %. Regarding the bonding structure of the doped boron, the ratios of BC bonds and BB bonds to the total number of BC bonds and BB bonds are 67% and 33%, respectively. According to secondary ion mass spectrometry (SIMS) analysis performed on the pellicle, the boron concentration in the interval from the surface of the pellicle to a depth of 5 nm is 1.0E21 / cm 3 .

[0037] [Comparative Example]

[0038] A 30 nm thick graphite layer was formed on the nickel layer by a CVD deposition process. A 10 nm thick B 4 C layer (i.e., covering layer) is used to prepare the surface film according to the comparative example. That is, in the surface film according to the comparative example, the surface of the graphite layer is covered with B 4 C layer coverage.

[0039] When EUV light emitted from the EUV system was irradiated on the surface film according to the comparative example, the surface film according to the comparative example was heated as a result of the irradiation of the EUV light. After the irradiation of the EUV light, the destruction of the surface film according to the comparative example was found. Further analysis showed that the graphite layer and the B 4 The difference in thermal expansion coefficient between the C layers leads to an increase in thermal stress exerted on the surface film and subsequent destruction of the surface film.

[0040] Figure 4 1 is a cross-sectional view showing a mask according to some example embodiments of the inventive concept. Figures 1 to 3 The described elements may be identified by the same reference numerals without repeating their repeated descriptions.

[0041] refer to Figure 4 , the mask RET may include a photomask PM, a pellicle PEL configured to protect the photomask PM, and a frame FR disposed between the photomask PM and the pellicle PEL.

[0042] The photomask PM may include a mask substrate MS and mask patterns MP on the mask substrate MS. The shape, size, and interval of the mask patterns MP are not limited to Figure 4The example shown in FIG. 1 and may be variously changed. The first surface PELa of the pellicle PEL may be exposed to the outside. The second surface PELb of the pellicle PEL may be disposed to face the photomask PM.

[0043] The frame FR may be between the pellicle PEL and the photomask PM. The pellicle PEL may be spaced apart from the photomask PM by the frame FR. The frame FR may be disposed between an edge portion of the pellicle PEL and an edge portion of the photomask PM. When viewed in a plan view (top view), the frame FR may have a quadrilateral, rectangular, or circular shape.

[0044] Although not shown, an adhesive layer may be interposed between the pellicle PEL and the frame FR. An adhesive layer may also be interposed between the frame FR and the mask substrate MS.

[0045] The pellicle PEL may be configured to protect or help protect the photomask PM from external contamination materials such as dust, resist, etc. In the case where the pellicle PEL is not provided on the photomask PM, the external contamination materials may adhere to the photomask PM, and this may cause various defects in the photolithography process. This will refer to Figure 7 and 8 Describe in more detail.

[0046] Figure 5 and 6 are conceptual diagrams, each of which illustrates an exposure system using a mask according to some example embodiments of the inventive concept. Figures 1 to 4 The described elements may be identified by the same reference numerals without repeating their repeated descriptions.

[0047] refer to Figure 4 and 5 The exposure system may include a light source LS, a first optical system OS1, a mask RET, and a second optical system OS2. The light source LS may be configured to generate light L1, and the first optical system OS1, the mask RET, and the second optical system OS2 may be configured to allow the light L1 to be incident on a substrate SUB.

[0048] The light L1 generated by the light source LS may be extreme ultraviolet (EUV) light. For example, the light source LS may be configured to generate EUV light having a wavelength of approximately 13.3 nm-13.5 nm. In some example embodiments, the light source LS may be configured to generate EUV light having a wavelength of 13.3 nm or less.

[0049] The first optical system OS1 may be an illumination optical system. For example, the first optical system OS1 may include at least one collimating lens and / or at least one alignment optical system. The second optical system OS2 may be a projection optical system. For example, the second optical system OS2 may include at least one reflecting component and / or at least one lens. The structures of each of the first and second optical systems OS1 and OS2 may be variously changed, and the inventive concept is not limited to a specific structure.

[0050] In some example embodiments, the mask RET may be or include a reflective mask. For example, the mask RET may include a photomask PM configured to reflect light incident thereto, and a pellicle PEL configured to protect the photomask PM. As an example, the mask substrate MS of the photomask PM may be configured to reflect EUV light, and the mask pattern MP of the photomask PM may be configured to absorb EUV light.

[0051] The light L1 generated by the light source LS may be reflected by the mask RET and then may be incident into the substrate SUB. The substrate SUB may include a region or layer to be patterned. For example, the substrate SUB may be a wafer on which a resist layer (not shown) is formed. The light reflected by the mask RET may be focused (concentrated) on the resist layer of the substrate SUB. As a result, the geometry of the mask pattern MP may be transferred to the substrate SUB.

[0052] refer to Figure 4 and 6 , the exposure system may include a light source LS, an optical system OS, and a mask RET. Light L1 emitted from the light source LS may be incident into the substrate SUB through the optical system OS and the mask RET. In detail, the light L1 emitted from the light source LS may be incident into the mask RET through the optical system OS, and then may be reflected by the mask RET to be incident into the substrate SUB through the optical system OS. The optical system OS may include the previously referenced Figure 5 The first optical system OS1 and the second optical system OS2 are described. For example, the optical system OS may include both an illumination optical system and a projection optical system.

[0053] Previous references provided Figure 5 and 6 The described exposure system and pellicle may be used for a photolithography process using EUV light. However, the inventive concept is not limited thereto, and the exposure system and pellicle therein may be used for a photolithography process in which light having a wavelength different from EUV light is used.

[0054] Reference Figure 5 A photolithography process using a mask according to some example embodiments of the inventive concepts is described in more detail.

[0055] refer to Figure 4 and 5In the exposure step of the photolithography process, hydrogen (H 2 ) is supplied to the first surface PELa of the pellicle PEL. The EUV light incident on the mask RET can be supplied to the first surface PELa of the pellicle PEL by 2 ) produces hydrogen ions (H + In other words, hydrogen ions (H + ).

[0056] In the comparative example, the surface film PEL may not have Figure 4 In this case, the first surface PELa of the pellicle PEL may be Figure 2A The first surface PELa of the surface film PEL may include C—H bonds, and in this case, hydrogen ions (H + ) and CH bonds to form volatile gases (such as CH 4 ). Due to the hydrogen ion (H + ), when the exposure step is repeated, the number of carbon atoms contained in the pellicle PEL may decrease. For example, when the exposure step is repeated, the first surface PELa of the pellicle PEL may be etched or recessed. Therefore, it may be difficult to use the pellicle PEL for a long time, and it may be necessary or desirable to replace the pellicle PEL more frequently.

[0057] In some example embodiments, the pellicle PEL may include a doped region DR adjacent to the first surface PELa, such as Figure 1 , 2B In the carbon atom layer in the doping region DR, the sites of the carbon atoms may be replaced by dopant atoms. The replaced dopant atoms may suppress the hydrogen ions (H + )’s reaction.

[0058] For example, the doping region DR may be formed to include BH bonds, and hydrogen ions (H + ) may not react with the BH bond. Therefore, the doped region DR may prevent or reduce the possibility of etching or recessing the first surface PELa of the pellicle PEL during the exposure step.

[0059] In some example embodiments, the pellicle PEL may have high transmittance to EUV light and / or may have high chemical and mechanical durability. In some example embodiments, the pellicle PEL may be used for a long time, and this may allow the pellicle PEL to have high economic efficiency.

[0060] Figure 7 2 is a conceptual diagram showing a photolithography process using a mask without a pellicle. Figure 7 , in which the mask used in the photolithography process is not set Figure 1In the case of a pellicle, the external contamination material DU may be directly adhered to the photomask PM. As an example, the external contamination material DU may be directly adhered to the mask pattern MP.

[0061] Light L1 reflected by the photomask PM may be incident into the resist layer PR disposed on the substrate SUB through the lens unit LENS. In the case where the external contamination material DU directly adheres to the mask pattern MP or the mask substrate MS, the external contamination material DU may cause various difficulties in patterning the resist layer PR.

[0062] Light reflected by the external contamination material DU may be focused on the resist layer PR, and in this case, the shape of the external contamination material DU may be transferred to the resist layer PR. As a result, there may be difficulty in patterning the resist layer PR into a desired shape. In the case where the line width of the desired pattern is reduced, the process of patterning the resist layer PR may be greatly affected by the presence of the external contamination material DU.

[0063] Figure 8 is a conceptual diagram showing a photolithography process using a mask having a pellicle. Figure 8 In the case where a mask RET having a pellicle PEL is used in a photolithography process (for example, referring to Figure 1 ), the external contamination material DU may be directly adhered to the first surface PELa of the pellicle PEL. Due to the pellicle PEL, the external contamination material DU may be spaced apart from the mask pattern MP and the mask substrate MS.

[0064] In the case where the external contamination material DU adheres to the pellicle PEL, the process of patterning the resist layer PR may not be significantly affected by the external contamination material DU. The light reflected by the external contamination material DU may not be focused on the resist layer PR and may be out of focus on the resist layer PR. In other words, the light reflected by the external contamination material DU may be provided to the resist layer PR in a defocused manner.

[0065] As a result, the external contamination material DU attached to the pellicle PEL may not affect the process of patterning the resist layer PR. As described above, the pellicle PEL according to some example embodiments of the inventive concept may be used to prevent or reduce the possibility that a photolithography process is affected by the presence of the external contamination material DU.

[0066] Fig. 9 and 10 are cross-sectional views illustrating a method of manufacturing a reticle according to some example embodiments of the inventive concepts.

[0067] refer to Fig. 9The membrane MEM may be formed on an underlying layer (lower layer) UL. The underlying layer UL may be formed of or include at least one of a metal material (e.g., Ni, Cu, and / or Pt), a metal oxide, a semiconductor material (e.g., Si and / or Ge), and / or an insulating material (e.g., silicon oxide and / or silicon nitride). The membrane MEM may be formed to have a thickness of about 5 nm to 100 nm.

[0068] In some example embodiments, the formation of the membrane MEM may include forming a layer formed of one of the carbon allotropes on the underlying UL using a deposition process, such as a chemical vapor deposition (CVD) process. The CVD process may be a thermal CVD process or a plasma CVD process. The plasma CVD may be an inductively coupled plasma CVD (ICPCVD) process or a plasma enhanced CVD (PECVD) process. The CVD process may be performed using a gas or a solid source material (i.e., a carbon-containing source material). The solid source material may include a polymer or an organic monomer.

[0069] In some example embodiments, forming a membrane MEM on an underlying layer UL may include supplying a solution including one of carbon allotropes onto the underlying layer UL. For example, the solution may be a graphene-containing solution prepared by mixing graphene particles of tens of nm or less with a solvent. The formation of the membrane MEM may further include performing a heat treatment process on a liquid layer formed by depositing the solution on the underlying layer UL.

[0070] For example, the solvent may include N-methylpyrrolidone (NMP), dimethylformamide (DMF), or ammonium hydroxide (NH4OH). 4 OH). The graphene particles may be or include graphene quantum dots (GQDs) and / or graphene nanoplates. In some example embodiments, graphene oxide particles may be included in a solution for a membrane MEM instead of or together with graphene particles. Graphene particles and graphene oxide particles may be prepared by a hydrothermal synthesis method. A graphene-containing solution may be deposited on an underlying UL using various deposition methods (e.g., a coating method or a film casting method). The heat treatment process may be performed at a temperature of about 2000° C. or less to heat treat the membrane MEM disposed on the underlying UL.

[0071] refer to Fig.10 , a dopant doping process may be performed to dope the membrane MEM with a dopant, thereby forming a surface membrane PEL. As a result of the dopant doping, a doping region DR may be formed in an upper portion of the membrane MEM. The doping region DR may be adjacent to a first surface PELa of the membrane MEM exposed to the outside. The dopant may be used to replace carbon atoms in the membrane MEM. As an example, at least one of boron (B) or nitrogen (N) may be used as a dopant in the doping region DR.

[0072] The dopant doping process may be performed using an ion implantation process IIP. In the ion implantation process IIP, ion acceleration energy may be in a range of about 100 eV to about 1,000 eV. In other words, the doped region DR may be formed using an ion implantation process IIP performed under relatively low energy conditions. Thus, the doped region DR may be formed to have a relatively shallow depth DE (e.g., about 4 nm to about 10 nm). The ion implantation process IIP may be performed at about 1.0E11 / cm 2 -1.0E20 / cm 2 The dopant concentration of the doping region DR may be the highest at the midpoint MID of the doping region DR.

[0073] Since the ion implantation process IIP according to the present embodiment is performed at a relatively low ion acceleration energy, the dopant may not be physically embedded in the membrane MEM or interstitial in the membrane MEM, but may chemically replace the carbon atoms in the membrane MEM. Figure 2B As shown in FIG. , a dopant (eg, boron) may replace a carbon atom in the doped region DR, and in this case, a BC bond and a BB bond may be formed in the doped region DR. Since the boron atom replaces the carbon atom, Figure 5 During the exposure process described above, it is possible to prevent or reduce the first surface PELa of the pellicle PEL from being exposed to hydrogen ions (H + ) possibility of etching.

[0074] Return to reference Figure 1 The pellicle PEL may be separated from the bottom layer UL and may be disposed on the photomask PM. The pellicle PEL may be disposed on the photomask PM to allow the first surface PELa of the pellicle PEL adjacent to the doping region DR to be exposed to the outside. A frame FR may be disposed between the photomask PM and the pellicle PEL. The frame FR may separate the mask pattern MP of the photomask PM from the pellicle PEL.

[0075] According to some example embodiments of the present inventive concept, the pellicle may be configured to have high transmittance to extreme ultraviolet (EUV) light and high chemical and mechanical durability. In addition, since the pellicle is not etched under a hydrogen atmosphere during a photolithography process, the pellicle may be economically used for a long time.

[0076] While example embodiments of the present inventive concepts have been particularly shown and described, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the spirit and scope of the following claims.

Claims

1. Surface membrane, including: a film, at least a portion of which comprises a carbon allotrope, wherein the film has a first surface and a second surface opposite to the first surface, the film comprising a doped region comprising a dopant, the doped region being adjacent to the first surface, The dopant includes at least one of boron or nitrogen, and The doped region includes bonds between atoms of at least one of the dopants and carbon atoms. 2 . The pellicle of claim 1 , wherein a concentration of the dopant in the doped region increases from the first surface to a midpoint of the doped region and decreases from the midpoint to the second surface.

3. The pellicle of claim 1, wherein the dopant comprises boron.

4. The pellicle of claim 1, wherein the atomic percentage of the dopant in the doped region ranges from 1 atomic % to 3 atomic % based on the total number of atoms in the doped region.

5. Surface membrane, including: a film, at least a portion of which comprises a carbon allotrope, wherein the film has a first surface and a second surface opposite to the first surface, the film comprising a doped region comprising a dopant, the doped region being adjacent to the first surface, The dopant includes boron, and a concentration of boron in the doped region increases from the first surface to a midpoint of the doped region and decreases from the midpoint to the second surface, The doped region includes BC bonds between boron atoms and carbon atoms.

6. The pellicle of claim 1 or 5, wherein the pellicle comprises a two-dimensional layer of carbon atoms, wherein at least a portion of the two-dimensional layer of carbon atoms comprises one of the carbon allotropes.

7. The pellicle of claim 1 or 5, wherein at least some of the dopants are bonded to each other.

8. The pellicle of claim 1 or 5, wherein the carbon allotrope comprises at least one of graphene, graphite, porous carbon, carbon nanowires, carbon nanotubes, or diamond.

9. The pellicle of claim 5, wherein the doped region comprises: at least one BC bond between a boron atom and a carbon atom; as well as At least one BB bond between boron atoms, where A ratio of the at least one BC bond to the sum of the at least one BB bond and the at least one BC bond in the doped region is greater than a ratio of the at least one BB bond to the sum of the at least one BB bond and the at least one BC bond.

10. The pellicle of claim 5, wherein the atomic percentage of boron in the doped region ranges from 1 atomic % to 3 atomic % based on the total number of atoms in the doped region.

11. The pellicle of claim 1 or 5, wherein the pellicle has a thickness ranging from 5 nm to 100 nm.

12. The pellicle of claim 1 or 5, wherein the first surface and the second surface are both exposed to air.

13. Mask, including: a photomask comprising a mask substrate and a mask pattern on the mask substrate; a pellicle including a first surface and a second surface opposite to the first surface, the first surface being exposed to the outside and the second surface facing the photomask; and a frame between the photomask and the pellicle, wherein The pellicle comprises a film at least a portion of which comprises a carbon allotrope, The pellicle includes a doped region containing a dopant, the doped region being adjacent to the first surface, and The dopant comprises at least one of boron or nitrogen, a concentration of the dopant in the doped region increases from the first surface to a midpoint of the doped region and decreases from the midpoint to the second surface, The doped region includes bonds between atoms of at least one of the dopants and carbon atoms.

14. The reticle of claim 13, wherein the doped region comprises a bond between at least two atoms of the dopant.

15. The reticle of claim 13, wherein the carbon allotrope comprises at least one of graphene, graphite, porous carbon, carbon nanowires, carbon nanotubes, or diamond.

16. The reticle of claim 13, wherein the pellicle is configured to be transparent to extreme ultraviolet (EUV) light.

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