A pellicle is a thin transparent film stretched over a frame that is glued over one side of a photo mask to protect the photo mask from damage, dust and/or moisture. In extreme ultraviolet (EUV) lithography, a pellicle having a high transparency in the EUV wavelength region, a high mechanical strength and a low thermal expansion is generally required.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific embodiments or examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, dimensions of elements are not limited to the disclosed range or values, but may depend upon process conditions and/or desired properties of the device. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Various features may be arbitrarily drawn in different scales for simplicity and clarity. In the accompanying drawings, some layers/features may be omitted for simplification.
Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. In addition, the term “made of” may mean either “comprising” or “consisting of.” Further, in the following fabrication process, there may be one or more additional operations in between the described operations, and the order of operations may be changed. In the present disclosure, the phrase “at least one of A, B and C” means either one of A, B, C, A+B, A+C, B+C or A+B+C, and does not mean one from A, one from B and one from C, unless otherwise explained. Materials, configurations, structures, operations and/or dimensions explained with one embodiment can be applied to other embodiments, and detained description thereof may be omitted.
EUV lithography is one of the crucial techniques for extending Moore's law. However, due to wavelength scaling from 193 nm (ArF) to 13.5 nm, the EUV light source suffers from strong power decay due to environmental adsorption. Even though a stepper/scanner chamber is operated under vacuum to prevent strong EUV adsorption by gas, maintaining a high EUV transmittance from the EUV light source to a wafer is still an important factor in EUV lithography.
A pellicle generally requires a high transparency and a low reflectivity. In UV or DUV lithography, the pellicle film is made of a transparent resin film. In EUV lithography, however, a resin based film would not be acceptable, and a non-organic material, such as a polysilicon, silicide or metal film, is used.
Carbon nanotubes (CNTs) are one of the materials suitable for a pellicle for an EUV reflective photo mask, because CNTs have a high EUV transmittance of more than 96.5%. Generally, a pellicle for an EUV reflective mask requires the following properties: (1) Long life time in a hydrogen radical rich operation environment in an EUV stepper/scanner; (2) Strong mechanical strength to minimize the sagging effect during vacuum pumping and venting operations; (3) A high or perfect blocking property for particles larger than about 20 nm (killer particles); and (4) A good heat dissipation to prevent the pellicle from being burnt out by EUV radiation. Other nanotubes made of a non-carbon based material are also usable for a pellicle for an EUV photo mask. In some embodiments of the present disclosure, a nanotube is a one dimensional elongated tube having a dimeter in a range from about 0.5 nm to about 100 nm.
In the present disclosure, a pellicle for an EUV photo mask includes a network membrane having a plurality of multiwall nanotubes that form a mesh structure having voids and a two-dimensional material layer at least partially filling the voids. Such a pellicle has a high EUV transmittance, improved mechanical strength, blocks killer particles from falling on an EUV mask, and/or has improved durability.
In some embodiments, a multiwall nanotube is a co-axial nanotube having two or more tubes co-axially surrounding an inner tube(s). In some embodiments, the main network membrane 100 includes only one type of nanotubes (single wall/multiwall, or material) and in other embodiments, different types of nanotubes form the main network membrane 100.
In some embodiments, a pellicle (support) frame 15 is attached to the main network membrane 100 to maintain a space between the main network membrane of the pellicle and an EUV mask (pattern area) when mounted on the EUV mask. The pellicle frame 15 of the pellicle is attached to the surface of the EUV photo mask with an appropriate bonding material. In some embodiments, the bonding material is an adhesive, such as an acrylic or silicon based glue or an A-B cross link type glue. The size of the frame structure is larger than the area of the black borders of the EUV photo mask so that the pellicle covers not only the circuit pattern area of the photo mask but also the black borders.
In some embodiments, the nanotubes in the main network membrane 100 include multiwall nanotubes, which are also referred to as co-axial nanotubes.
The number of tubes of the multiwall nanotubes is not limited to three. In some embodiments, the multiwall nanotube has two co-axial nanotubes as shown in
In some embodiments, each of the nanotubes of the multiwall nanotube is one selected from the group consisting of a carbon nanotube, a boron nitride nanotube, a transition metal dichalcogenide (TMD) nanotube, where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te. In some embodiments, at least two of the tubes of the multiwall nanotube are made of a different material from each other. In some embodiments, adjacent two layers (tubes) of the multiwall nanotube are made of a different material from each other. In some embodiments, an outermost nanotube of the multiwall nanotube is a non-carbon based nanotube.
In some embodiments, the outermost tube or outermost layer of the multiwall nanotubes is made of at least one layer of an oxide, such as HfO2, Al2O3, ZrO2, Y2O3, or La2O3; at least one layer of non-oxide compounds, such as B4C, YN, Si3N4, BN, NbN, RuNb, YF3, TiN, or ZrN; or at least one metal layer made of, for example, Ru, Nb, Y, Sc, Ni, Mo, W, Pt, or Bi.
In some embodiments, the multiwall nanotube includes three co-axially layered tubes made of different materials from each other. In other embodiments, the multiwall nanotube includes three co-axially layered tubes, in which the innermost tube (first tube) and the second tube surrounding the innermost tube are made of materials different from each other, and the third tube surrounding the second tube is made of the same material as or different material from the innermost tube or the second tube.
In some embodiments, the multiwall nanotube includes four co-axially layered tubes each made of different materials A, B or C. In some embodiments, the materials of the four layers are from the innermost (first) tube to the fourth tube, A/B/A/A, A/B/A/B, A/B/A/C, A/B/B/A, A/B/B/B, A/B/B/C, A/B/C/A, A/B/C/B, or A/B/C/C.
In some embodiments, all the tubes of the multiwall nanotube are crystalline nanotubes. In other embodiments, one or more tubes are a non-crystalline (e.g., amorphous) layer wrapping around the one or more inner tubes. In some embodiments, the outermost tube is made of, for example, a layer of HfO2, Al2O3, ZrO2, Y2O3, La2O3, B4C, YN, Si3N4, BN, NbN, RuNb, YF3, TiN, ZrN. Ru, Nb, Y, Sc, Ni, Mo, W, Pt, or Bi.
In some embodiments, a diameter of the innermost nanotube is in a range from about 0.5 nm to about 20 nm and is in a range from about 1 nm to about 10 nm in other embodiments. In some embodiments, a diameter of the multiwall nanotubes (i.e., diameter of the outermost tube) is in a range from about 3 nm to about 40 nm and is in a range from about 5 nm to about 20 nm in other embodiments. In some embodiments, a length of the multiwall nanotube is in a range from about 0.5 μm to about 50 μm and is in a range from about 1.0 μm to about 20 μm in other embodiments.
In some embodiments, the network membrane 100 includes a plurality of multiwall nanotubes 101 as shown in
In some embodiments, the main network layer 100 includes a plurality of one or more types of multiwall nanotubes 101, and a plurality of one or more types of single wall nanotubes 111, as shown in
In some embodiments, the network membrane 100 has a single layer 110 of a plurality of multiwall nanotubes as shown in
In some embodiments, nanotubes are formed by a chemical vapor deposition (CVD) process. In some embodiments, a CVD process is performed by using a vertical furnace as shown in
In some embodiments, a stage or a susceptor, on which the support membrane 80 is disposed, rotates continuously or intermittently (step-by-step manner) so that the synthesized nanotubes are deposited on the support membrane 80 with different or random directions.
In some embodiments, after the elongated single wall nanotubes is grown from the catalysts on the support frame or bar, one or more outer nanotubes are formed co-axially wrapping around the single wall nanotubes. In some embodiments, BN nanotubes and/or TMD nanotubes are formed around single wall carbon nanotubes by CVD. In some embodiments, metal sources (Mo, W, etc) and chalcogen source are supplied as gas sources into the vertical furnace. In a case of forming a MoS2 layer, a Mo(CO)6 gas, a MoCl5 gas, and/or a MoOCl4 gas are used as a Mo source, and a H2S gas and/or a dimethylsulfide gas are used as a S source, in some embodiments.
In some embodiments, the nanotube sheet is placed on a support membrane 80 as shown in
In some embodiments, two or more nanotube sheets having a desired shape to fit a pellicle frame are stacked and attached to the pellicle frame 15 forming the network membrane, such that the two adjacent layers of the nanotube sheets have different alignment axes (e.g., different orientations), as shown in
In some embodiments, nanotubes are dispersed in a solution as shown in
As shown in
As shown in
In some embodiments, a Mo containing gas (e.g., MoO3 gas) sublimed from a solid MoO3 or a MoCl5 source and/or a S containing gas sublimed from a solid S source is used, as shown in
In other embodiments, one of the solid sources, e.g., metal sources (Mo, W, etc) is supplied as a gas source into the chamber as shown in
In some embodiments, multiwall nanotubes having a BN nanotube as an outer nanotube is formed by CVD, as shown in
Other TMD layers can also be formed by CVD using suitable source gases. For example, metal oxides, such as WO3, PdO2 and PtO2 can be used as a sublimation source for W, Pd and Pt, respectively, and metal compounds, such as W(CO)6, WF6, WOCl4, PtCl2 and PdCl2 can also be used as a metal source. In other embodiments, the seed nanotubes are immersed in, dispersed in or treated by, one or more metal precursor, such as (NH4)WS4, WO3, (NH4)MoS4 or MoO3 and placed over the substrate, and then a sulfur gas is provided over the substrate to form multiwall nanotubes.
Three or more co-axial nanotubes are formed by repeating the above processes in some embodiments.
In some embodiments, as shown in
As set forth above, a network membrane including one or more layers of single wall nanotubes and/or multiwall nanotubes are formed. In some embodiments, each of the layers forms a mesh structure having a plurality of voids or spaces. As shown in
In some embodiments, the two-dimensional material layer 120 include at least one of boron nitride (BN), and/or transition metal dichalcogenides (TMDs), represented by MX2, where M=Mo, W, Pd, Pt, and/or Hf, and X=S, Se and/or Te. In some embodiments, a TMD is one of MoS2, MoSe2, WS2 or WSe2. In some embodiments, a thickness of the two-dimensional material layer 120 is in a range from about 0.3 nm to about 3 nm and is in a range from about 0.5 nm to about 1.5 nm in other embodiments. In some embodiments, a number of the two-dimensional material layers is 1 to about 20, and is 2 to about 5 in other embodiments.
In some embodiments, the two-dimensional layers are formed by CVD using a transition metal source gas and a chalcogen source gas similar to the processes as explained with respect to
In some embodiments, the network membrane includes the voids each having an area of 10 nm2 to 1000 nm2 and the two-dimensional layer fills each void by about 30% to about 100% in area in plan view (as a surface area). Thus, some of the voids are fully filled or blocked by the two-dimensional layer, and some of the voids are only partially filled or blocked by the two-dimensional layer.
The network membrane with the two-dimensional material layers is attached to the pellicle frame as shown in
A nanotube layer 90 is formed on a support membrane 80 by one or more method as explained above. In some embodiments, the nanotube layer 90 includes single wall nanotubes, multi wall nanotubes, or mixture thereof. In some embodiments, the nanotube layer 90 includes single wall nanotubes only. In some embodiments, the single wall nanotubes are non-carbon based nanotubes, such as BN nanotubes or TMD nanotubes.
Then, as shown in
Next, as shown in
Then, in some embodiments, one or more outer nanotubes are formed around each of the nanotubes (e.g., single nanotubes) and/or two-dimensional material layers are formed to at least partially fill voids of the nanotube layer 90, to form a network membrane 100, as shown in
In some embodiments, when a multiwall nanotube layer 91 is directly formed over the support membrane 80, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, the main membrane of the pellicle is a single layer of a nanotube network as shown in
In some embodiments, the main membrane includes a nanotube layer having a mesh structure formed by single wall nanotubes, in which voids of the mesh structure are partially or fully filled by two-dimensional material layers as shown in
In some embodiments, the main membrane is made of boron nitride nanotubes without carbon nanotubes. As explained with respect to
Then, similar to the process explained with respect to
In some embodiments, similar to the process as explained with
Subsequently, the carbon nanotubes as the inner tubes are removed as shown in FIG. 17B. In some embodiments, the carbon nanotubes are removed by a heating or annealing process in an oxygen containing ambient at a temperature in a range from about 300° C. to about 800° C. In some embodiments, the carbon nanotubes are fully removed. As shown in
The pellicle made of boron nitride (only) has a higher EUV transmittance of about 90% to about 96% with a higher film strength. In some embodiments, other non-carbon based nanotubes and non-carbon based two-dimensional material layers can be used instead of or in addition to boron nitride nanotubes and/or two-dimensional material layers. In some embodiments, the material of such nanotubes are the same as or different from the material of the two-dimensional material layers.
At S804 of
The pellicles according to embodiments of the present disclosure provide higher strength and thermal conductivity (dissipation) as well as higher EUV transmittance than conventional pellicles. In the foregoing embodiments, multiwall nanotubes are used as a main network membrane to increase the mechanical strength of the pellicle and obtain a high EUV transmittance. Further, a two-dimensional material layer is directly formed over the nanotube mesh network to partially or fully fills the voids in the mesh network to increase the mechanical strength of a pellicle, to improve thermal dissipation property of the pellicle, and to provide a high or perfect blocking property of killer particles.
It will be understood that not all advantages have been necessarily discussed herein, no particular advantage is required for all embodiments or examples, and other embodiments or examples may offer different advantages.
In accordance with one aspect of the present disclosure, in a method of manufacturing a pellicle for an extreme ultraviolet (EUV) reflective mask, a layer of inner nanotubes is formed, outer nanotubes are formed over the inner nanotubes to form a nanotube layer, two-dimensional material layers are formed over the nanotube layer, and the inner nanotubes are removed. In one or more of the foregoing and following embodiments, the inner nanotubes are made of carbon nanotubes. In one or more of the foregoing and following embodiments, the outer nanotubes are made of boron nitride. In one or more of the foregoing and following embodiments, the two-dimensional material layers are made of boron nitride. In one or more of the foregoing and following embodiments, the inner nanotubes are removed by a thermal process in an oxygen containing ambient. In one or more of the foregoing and following embodiments, a thickness of the two-dimensional material layers is in a range from 0.3 nm to 3 nm. In one or more of the foregoing and following embodiments, a number of layers of the two-dimensional material layers is 1 to 5. In one or more of the foregoing and following embodiments, two or more co-axial outer nanotubes are formed around each of the inner nanotubes. In one or more of the foregoing and following embodiments, a number of the co-axial outer nanotubes is 1, 2 or 3.
In one or more of the foregoing and following embodiments, the outer nanotubes are made of a non-carbon based material. In one or more of the foregoing and following embodiments, the non-carbon based material is a transition metal dichalcogenide (TMD), where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te. In one or more of the foregoing and following embodiments, the two-dimensional material layers are made of a non-carbon based material. In one or more of the foregoing and following embodiments, the non-carbon based material is a transition metal dichalcogenide (TMD), where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te.
In accordance with another aspect of the present disclosure, in a method of manufacturing a pellicle for an extreme ultraviolet (EUV) reflective mask, a layer of inner nanotubes is formed, outer nanotubes are formed over the inner nanotubes to form a nanotube layer, and the inner nanotubes are moved. In one or more of the foregoing and following embodiments, the inner nanotubes are made of carbon nanotubes. In one or more of the foregoing and following embodiments, the outer nanotubes are made of boron nitride. In one or more of the foregoing and following embodiments, the inner nanotubes are removed by a thermal process in an oxygen containing ambient. In one or more of the foregoing and following embodiments, the layer of inner nanotubes is attached to a pellicle frame. In one or more of the foregoing and following embodiments, the nanotube layer is attached to a pellicle frame. In one or more of the foregoing and following embodiments, the outer nanotubes are made of a non-carbon based material. In one or more of the foregoing and following embodiments, the non-carbon based material is a transition metal dichalcogenide (TMD), where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te.
In accordance with another aspect of the present disclosure, a pellicle for an extreme ultraviolet (EUV) reflective mask includes a pellicle frame, and a main membrane attached to the pellicle frame. The main membrane includes network of boron nitride nanotubes without containing a carbon nanotube. In one or more of the foregoing and following embodiments, at least two inner spaces of the boron nitride nanotubes are connected. In one or more of the foregoing and following embodiments, the pellicle further includes two-dimensional material layers made of boron nitride filling spaces or voids between the boron nitride nanotubes.
In accordance with one aspect of the present disclosure, a pellicle for an extreme ultraviolet (EUV) reflective mask includes a pellicle frame and a main membrane attached to the pellicle frame. The main membrane includes a plurality of nanotubes, each of which includes a single nanotube or a co-axial nanotube, and the single nanotube or an outermost nanotube of the co-axial nanotube is a non-carbon based nanotube. In one or more of the foregoing and following embodiments, the non-carbon based nanotube is one selected from the group consisting of a boron nitride nanotube and a transition metal dichalcogenide (TMD) nanotube, where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te. In one or more of the foregoing and following embodiments, the plurality of nanotubes include the co-axial nanotube having an inner tube and one or more outer tubes, and the inner tube is a carbon nanotube. In one or more of the foregoing and following embodiments, the plurality of nanotubes include the co-axial nanotube having an inner tube and one or more outer tubes made of a different material than the inner tube. In one or more of the foregoing and following embodiments, the plurality of nanotubes include the co-axial nanotube having an inner tube and one or more outer tubes, all of which are made of different materials from each other. In one or more of the foregoing and following embodiments, the plurality of nanotubes include the co-axial nanotube having an inner tube and one or more outer tubes, all of which are the non-carbon based nanotube. In one or more of the foregoing and following embodiments, the main membrane comprises a mesh formed by the plurality of nanotubes.
In accordance with another aspect of the present disclosure, a pellicle for an extreme ultraviolet (EUV) reflective mask includes a pellicle frame and a main membrane attached to the pellicle frame. The main membrane includes a plurality of nanotube layers, and nanotubes of a first layer of the plurality of nanotube layers are arranged along a first axis and nanotubes of a second layer of the plurality of nanotube layers adjacent to the first layer are arranged along a second axis crossing the first axis. In one or more of the foregoing and following embodiments, more than 90% of the nanotubes of the first layer have angles of ±15 degrees with respect to the first axis, when each of the nanotubes of the first layer is subjected to linear approximation, and more than 90% of the nanotubes of the second layer have angles of ±15 degrees with respect to the second axis, when each of the nanotubes of the second layer is subjected to linear approximation. In one or more of the foregoing and following embodiments, the first axis and the second axis form an angle of 30 degrees to 90 degrees. In one or more of the foregoing and following embodiments, a total number of layers of the plurality of nanotube layers is 2 to 8. In one or more of the foregoing and following embodiments, one layer of the plurality of nanotube layers comprises a plurality of single wall nanotubes covered by a non-carbon based material layer. In one or more of the foregoing and following embodiments, the non-carbon based material layer is made of one selected from the group consisting of boron nitride and transition metal dichalcogenide (TMD), where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te. In one or more of the foregoing and following embodiments, at least one of the single wall nanotubes touches another of the single wall nanotubes without interposing the non-carbon based material layer. In one or more of the foregoing and following embodiments, the non-carbon based material layer comprises a nanotube co-axially surrounding each of the plurality of single wall nanotubes. In one or more of the foregoing and following embodiments, each layer of the plurality of nanotube layers comprises a plurality of multiwall nanotubes. In one or more of the foregoing and following embodiments, each of the plurality of multiwall nanotubes comprises an inner tube and one or more outer tubes made of a non-carbon based material.
In accordance with another aspect of the present disclosure, a pellicle for an extreme ultraviolet (EUV) reflective mask includes a pellicle frame and a main membrane attached to the pellicle frame. The main membrane includes a mesh of a plurality of nanotubes and a two-dimensional material layer at least partially filling spaces of the mesh. In one or more of the foregoing and following embodiments, the two-dimensional material layer includes at least one selected from the group consisting of boron nitride (BN), MoS2, MoSe2, WS2, and WSe2. In one or more of the foregoing and following embodiments, at least one of the spaces is fully filled by the two-dimensional material layer, and at least one of the spaces is only partially filled by the two-dimensional material layer. In one or more of the foregoing and following embodiments, the plurality of nanotubes include single wall nanotubes. In one or more of the foregoing and following embodiments, the plurality of nanotubes include multiwall nanotubes. In one or more of the foregoing and following embodiments, the main membrane includes voids each having an area of 10 nm2 to 1000 nm2.
In accordance with another aspect of the present disclosure, in a method of manufacturing a pellicle for an extreme ultraviolet (EUV) reflective mask, a nanotube layer including a plurality of nanotubes is formed, and a two-dimensional material layer is formed over the nanotube layer. In one or more of the foregoing and following embodiments, the nanotube layer comprises a mesh of the plurality of nanotubes, and the two-dimensional material layer grows from intersections of the mesh as seeds. In one or more of the foregoing and following embodiments, the two-dimensional material layer is one selected from the group consisting of boron nitride and transition metal dichalcogenide (TMD), where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te. In one or more of the foregoing and following embodiments, a thickness of the two-dimensional material layer is in a range from 0.3 nm to 3 nm. In one or more of the foregoing and following embodiments, a number of layers of the two-dimensional material layer is 1 to 10. In one or more of the foregoing and following embodiments, the plurality of nanotubes are single wall nanotubes. In one or more of the foregoing and following embodiments, the single wall nanotubes are made of a non-carbon based material. In one or more of the foregoing and following embodiments, the non-carbon based material is one selected from the group consisting of boron nitride and transition metal dichalcogenide (TMD), where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te. In one or more of the foregoing and following embodiments, the plurality of nanotubes are multiwall nanotubes. In one or more of the foregoing and following embodiments, at least one tube of each of the multiwall nanotubes is made of one selected from the group consisting of boron nitride and transition metal dichalcogenide (TMD), where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te.
In accordance with another aspect of the present disclosure, in a method of manufacturing a pellicle for an extreme ultraviolet (EUV) reflective mask, a first nanotube layer including a plurality of nanotubes is formed, a second nanotube layer including a plurality of nanotubes is formed, and the first nanotube layer and the second nanotube layer are stacked over a pellicle frame. The plurality of nanotubes of the first nanotube layer are arranged along a first axis and the plurality of nanotubes of the second nanotube layer are arranged along a second axis, and the first nanotube layer and the second nanotube layer are stacked so that the first axis crosses the second axis. In one or more of the foregoing and following embodiments, more than 90% of the plurality of nanotubes of the first nanotube layer have angles of ±15 degrees with respect to the first axis, when each of the plurality of nanotubes of the first nanotube layer is subjected to linear approximation, and more than 90% of the plurality of nanotubes of the second nanotube layer have angles of ±15 degrees with respect to the second axis, when each of the plurality of nanotubes of the second nanotube layer is subjected to linear approximation. In one or more of the foregoing and following embodiments, the first axis and the second axis form an angle of 30 degrees to 90 degrees. In one or more of the foregoing and following embodiments, at least one of the first nanotube layer or the second nanotube layer comprises a plurality of single wall nanotubes made of a non-carbon based material. In one or more of the foregoing and following embodiments, the non-carbon based material is made of one selected from the group consisting of boron nitride and transition metal dichalcogenide (TMD), where TMD is represented by MX2, where M is one or more of Mo, W, Pd, Pt, or Hf, and X is one or more of S, Se or Te. In one or more of the foregoing and following embodiments, at least one of the first nanotube layer or the second nanotube layer comprises a plurality of multiwall nanotubes. In one or more of the foregoing and following embodiments, each of the plurality of multiwall nanotubes comprises an inner tube and one or more outer tubes made of a non-carbon based material.
In accordance with another aspect of the present disclosure, in a method of manufacturing a pellicle for an extreme ultraviolet (EUV) reflective mask, a nanotube layer including a plurality of nanotubes is formed over a support substrate while rotating the support substrate, a pellicle frame is attached over the nanotube layer, and the nanotube layer is detached from the support substrate. In one or more of the foregoing and following embodiments, the plurality of nanotubes include a non-carbon based material. In one or more of the foregoing and following embodiments, the plurality of nanotubes form a mesh having voids each having an area of 10 nm2 to 1000 nm2.
The foregoing outlines features of several embodiments or examples so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments or examples introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
This application is a continuation-in-part of U.S. patent application Ser. No. 17/710,545 filed Mar. 31, 2022, which claims priority of U.S. Provisional Patent Application No. 63/294,719 filed on Dec. 29, 2021, the entire contents of which are incorporated herein by reference. Further, the entire contents of U.S. Provisional Patent Application Nos. 63/230,555 and 63/230,576 both filed Aug. 6, 2021 are incorporated herein by reference.
Number | Date | Country | |
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63294719 | Dec 2021 | US |
Number | Date | Country | |
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Parent | 17710545 | Mar 2022 | US |
Child | 18139266 | US |