Patent Application
20240094626
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 low or no contamination is generally required. An EUV transmitting membrane is also used in an EUV lithography apparatus instead of a pellicle.
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 nanotubes covered by one or more cover layers. Further, a method of forming one or more cover layer over the nanotubes to increase mechanical and chemical strength is also disclosed.
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 nanotube (single wall/multiwall, or material) and in other embodiments, different types of nanotubes form the main network membrane 100. In some embodiments, the multiwall nanotubes are multiwall carbon nanotubes. In some embodiments, some of the multiwall nanotubes form a bundle of nanotubes by being closely attached to each other.
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, 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, carbon 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, carbon nanotubes are dispersed in a solution as shown in
As shown in
As shown in
As shown in
Then, as shown in
Next, as shown in
In some embodiments of the present disclosure, a nanotube in a pellicle membrane is coated with one or more coating layers.
In the flow of
In some embodiments, a first coating layer 130 is formed over a single wall nanotube 100S or a multiwall nanotube 100M as shown in
In some embodiments, the first coating layer 130 contains silicon and one or more metal elements, for example, transition metal elements. In some embodiments, the first coating layer is made of silicide. In some embodiments, the first coating layer 130 is a silicide of one or more of Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Ir or Rh (i.e., MSi, where M is one or more of Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Jr or Rh). When an EUV transmittance of the nanotube membrane is about 97%, the nanotube membrane with silicide coated nanotubes has more than about 90% EUV transmittance with a coating layer thickness of 10 nm. In some embodiments, when the metal elements are Zr, Nb or Mo, the nanotube membrane with silicide coated nanotubes has more than about 93% EUV transmittance at a coating layer thickness of 10 nm. The coating layer can prevent the carbon nanotubes from being damaged by, for example, hydrogen gas and/or EUV radiation.
In some embodiments, the first coating layer 130 is silicide containing nitrogen, i.e., silicide-nitride of transition metals represented by MSiN, where M is one or more of Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Jr or Rh.
In some embodiments, a thickness of the first coating layer 130 is in a range from 2 about nm to about 20 nm and is in a range from about 3 nm to about 10 nm in other embodiments. In some embodiments, the thickness of the first coating layer 130 is not uniform. The first coating layer 130 is formed by chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD) or any other suitable film formation methods.
In some embodiments, a second coating layer 140 is formed over the first coating layer 130 as shown in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, the annealing operation is performed at a temperature in a range from 200° C. to 1000° C. and at a temperature in a range from 500° C. to 800° C. in other embodiments. In some embodiments, the annealing operation is performed for 5 min to 60 min and for 10 min to 30 min in other embodiments. The apparatus and method of the annealing operation are explained below.
In some embodiments, the annealing operation includes a Joule heating treatment, in which a current is applied to pass through the membrane to generate heat, using a Joule heating apparatus as described below.
In some embodiments, as shown in
In other embodiments, as shown in
The Joule heating apparatus on which the pellicle 10 or the membrane 100 is mounted is placed in a vacuum chamber 60 as shown in
In the Joule heating operation, the vacuum chamber is evacuated to a pressure equal to or lower than 0.01 Torr in some embodiments. In some embodiments, the pressure is in a range from about 1×10−7 Torr to about 1×10−2 Torr. The power supply 58 applies current to the membrane 100 so that the current passes through the membrane generating heat. In some embodiments, the current is DC, and in other embodiments, the current is AC or pulse current.
In some embodiments, the current from the power supply 58 is adjusted such that the membrane is heated at a temperature in a range from about 200° C. to 1000° C. In some embodiments, the temperature is in a range from about 500° C. to about 800° C. In some embodiments, the pellicle frame 15 is made of ceramic or a metal or metallic material having a higher electric resistance than the carbon nanotube membrane 100.
In some embodiments, the Joule heating treatment is performed in an inert gas ambient, such as N2 and/or Ar (and free from oxidizing gas). In some embodiments, the Joule heating is performed in an ambient containing NH3. In some embodiments, the Joule heating treatment is performed for about five seconds to about 60 minutes, and is performed for about 30 seconds to about 15 minutes in other embodiments. When the heating time is shorter than these ranges, the silicide layer may not be fully formed, and when the heating time is longer than these ranges, a cycle time or a process efficiency may be degraded and the pellicle may be damaged.
In some embodiments, as shown in
In some embodiments, a Joule heating process is performed using induction heating as shown in
In some embodiments, the annealing operation includes a plate baking operation, or a lamp annealing operation, as described below.
As shown in
In some embodiments, the first coating layer 130 is formed by using ALD with a Si precursor and a metal M precursor. In some embodiments, the Si and/or metal precursor includes an organic Si or metal compound and/or a metal or Si chloride. In some embodiments, the metal is Zr, and thus in the ALD operation, a Zr containing precursor and a Si containing precursor are alternately supplied to the nanotube membrane.
In some embodiments, the Zr containing precursor is zirconium tetra-tert-butoxide (Zr[OC(CH3)3]4) (zirconium tetra-tert-butoxide (ZTB)) or ZrCl4. In some embodiments, the Si containing precursor is SiCl4 or tetra butyl orthosilicate (tetra butoxysilane (TB OS)).
In some embodiments, ZrCl4 and TBOS are used in the ALD to form ZrSi2 or silicate. In some embodiments, the membrane is heated at a temperature in a range from about 300° C. to about 500° C. In some embodiments, a bubbling temperature of ZrCl4 is in a range from about 140° C. to about 180° C. (e.g., 160° C.) and a bubbling temperature of TBOS is in a range from about 90° C. to about 100° C. (e.g., 95° C.). In some embodiments, a vapor pressure of ZrCl4 is set at about 0.10 Torr to about 0.20 Torr (e.g., 0.15 Torr), and a vapor pressure of TBOS is set at about 1.0 Torr to about 1.2 Torr (e.g., 1.1 Torr). The deposition pressure is about 0.2 Torr to about 5 Torr (e.g., 1 Torr) in some embodiments. In some embodiments, a carrier gas is Ar with a flow rate of about 15 sccm to about 25 sccm (e.g., 20 sccm). In some embodiments, the precursors are supplied as gas pulses with a pulse time of about 0.01 sec to about 5 sec, with a purge time of about 1 sec to about 30 sec. In some embodiments, a purge gas is Ar with a flow rate of about 400 sccm to about 600 sccm (e.g., 500 sccm). In some embodiments, the pulse time of ZrCl4 (e.g., 5 sec±10%) is longer than the pulse time of TBOS (e.g., 2 sec±10%). Each gas pulse is supplied twice or more (up to 10 times) in some embodiments.
In some embodiments, SiCl4 and ZTB are used in the ALD to form ZrSi2 or silicate. In some embodiments, the membrane is heated at a temperature in a range from about 125° C. to about 225° C. In some embodiments, a bubbling temperature of SiCl4 is in a range from about −10° C. to about 25° C. (e.g., 0° C.) and a bubbling temperature of ZTB is in a range from about 25° C. to about 80° C. (e.g., 50° C.). In some embodiments, a vapor pressure of SiCl4 is set at about 60 Torr to about 90 Torr (e.g., 77 Torr), and a vapor pressure of ZTB is set at about 0.3 Torr to about 0.6 Torr (e.g., 0.44 Torr). The deposition pressure is about 0.2 Torr to about 5 Torr (e.g., 1 Torr) in some embodiments. In some embodiments, a carrier gas is Ar with a flow rate of about 5 sccm to about 15 sccm (e.g., 10 sccm). In some embodiments, the precursors are supplied as gas pulses with a pulse time of about 0.01 sec to about 5 sec, with a purge time of about 1 sec to about 30 sec. In some embodiments, a purge gas is Ar with a flow rate of about 400 sccm to about 600 sccm (e.g., 500 sccm). In some embodiments, the pulse time of SiCl4 (e.g., 5 sec±10%) is longer than the pulse time of ZTB (e.g., 2 sec±10%). Each gas pulse is supplied twice or more (up to 10 times) in some embodiments.
In some embodiments, after the ALD operation, an annealing operation as set forth above is performed to form a ZrSi2 layer as a first coating layer.
In some embodiments, after the nanotube membrane is formed as shown in
In other embodiments, as shown in
In some embodiments, the nano-particles are formed by CVD, PVD or ALD. In some embodiments, a size (e.g., diameter or length) of the nano-particle is in a range from 1 nm to 5 nm. In some embodiments, the nano-particles function as an absorber of hydrogen atoms from hydrogen gas, thereby preventing damage to the CNTs.
In some embodiments, as shown in
In some embodiments, a pellicle membrane is formed by stacking two or more thin nanotube membranes. In the flow of
In other embodiments, in the flow of
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, the nanotube sheet is placed on a dummy frame 81 as shown in
In some embodiments, the nanotubes of the nanotube sheet are substantially aligned with a specific direction, e.g., X direction as shown in
In some embodiments, two or more nanotube sheets having first and/or second coating layers and 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, the pellicle of the present embodiments further includes one or more cover layers. The cover layer(s) is attached to the membrane after the first and/or second coating layers are formed over nanotubes of the nanotube membrane.
In some embodiments, a first cover sheet (or layer) 520 is formed at the bottom surface of the network membrane 100 between the frame 15 and the network membrane 100 as shown in
In some embodiments, one of or both of the first cover layer 520 and the second cover layer 530 include a two-dimensional material in which one or more two-dimensional layers are stacked. Here, a “two-dimensional” layer refers to one or a few crystalline layers of an atomic matrix or a network having thickness within the range of about 0.1-5 nm, in some embodiments. In some embodiments, the two-dimensional materials of the first cover layer 520 and the second cover layer 530 are the same or different from each other. In some embodiments, the first cover layer 520 includes a first two-dimensional material and the second cover layer 530 includes a second two-dimensional material.
In some embodiments, the two-dimensional material for the first cover layer 520 and/or the second cover layer 530 includes at least one of boron nitride (BN), graphene, 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 total thickness of each of the first cover layer 520 and the second cover layer 530 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 layers of each of the two-dimensional materials of the first and/or second cover layers is 1 to about 20, and is 2 to about 10 in other embodiments. When the thickness and/or the number of layers is greater than these ranges, EUV transmittance of the pellicle may be decreased and when the thickness and/or the number of layers is smaller than these ranges, mechanical strength of the pellicle may be insufficient.
In some embodiments, a third cover layer 540 includes at least one layer of an oxide, such as HfO2, Al2O3, ZrO2, Y2O3, or La2O3. In some embodiments, the third cover layer 540 includes at least one layer of non-oxide compounds, such as B4C, YN, Si3N4, BN, NbN, RuNb, YF3, TiN, or ZrN. In some embodiments, the third cover layer 540 includes at least one metal layer made of, for example, Ru, Nb, Y, Sc, Ni, Mo, W, Pt, or Bi. In some embodiments, the third cover layer 540 is a single layer, and in other embodiments, two or more layers of these materials are used as the third cover layer 540. In some embodiments, a thickness of the third cover layer is in a range from about 0.1 nm to about 5 nm, and is in a range from about 0.2 nm to about 2.0 nm in other embodiments. When the thickness of the third cover layer 540 is greater than these ranges, EUV transmittance of the pellicle may be decreased and when the thickness of the third cover layer 540 is smaller than these ranges, the mechanical strength of the pellicle may be insufficient.
In some embodiments, the thickness of the network membrane 100 is in a range from about 5 nm to about 100 nm, and is in a range from about 10 nm to about 50 nm in other embodiments. When the thickness of the network membrane 100 is greater than these ranges, EUV transmittance may be decreased and when the thickness of the network membrane 100 is smaller than these ranges, the mechanical strength may be insufficient.
At S804 of
In some embodiments, the network membrane including carbon nanotubes, on which one or more coating layers are formed is used for an EUV transmissive window, a debris catcher disposed between an EUV lithography apparatus and an EUV radiation source, or any other parts in an EUV lithography apparatus where a high EUV transmittance is required.
In the foregoing embodiments, a pellicle membrane include nanotubes (e.g., CNTs), on the surface of each of which one or more coating layers are formed. The pellicles according to embodiments of the present disclosure provide higher strength as well as higher EUV transmittance than conventional pellicles.
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, a pellicle for an extreme ultraviolet (EUV) photomask includes a pellicle frame and a main membrane attached to the pellicle frame. The main membrane includes a plurality of nanotubes, and each of the plurality of nanotubes is covered by a coating layer containing Si and one or more metal elements. In one or more of the foregoing and following embodiments, the coating layer is made of silicide. In one or more of the foregoing and following embodiments, the one or more metal elements are transition metal. In one or more of the foregoing and following embodiments, the transition metal includes Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Ir or Rh. In one or more of the foregoing and following embodiments, the coating layer is made of silicide containing nitrogen. In one or more of the foregoing and following embodiments, the one or more metal elements are transition metal. In one or more of the foregoing and following embodiments, the transition metal includes Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Jr or Rh. In one or more of the foregoing and following embodiments, the plurality of nanotubes includes single wall carbon nanotubes. In one or more of the foregoing and following embodiments, the plurality of nanotubes includes multi wall nanotubes. In one or more of the foregoing and following embodiments, the plurality of nanotubes includes multi wall carbon nanotubes. In one or more of the foregoing and following embodiments, a thickness of the coating layer is in a range from 2 nm to 20 nm.
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 nanotubes, and each of the plurality of nanotubes is covered by a first coating layer made of silicide or silicide-nitride and a second coating layer disposed over the first coating layer. In one or more of the foregoing and following embodiments, the second coating layer has a lower oxidation rate than the first coating layer. In one or more of the foregoing and following embodiments, the second coating layer includes one of AlN, TiN or SiC. In one or more of the foregoing and following embodiments, the first coating layer includes one or more of Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Jr or Rh. In one or more of the foregoing and following embodiments, a thickness of the first coating layer is in a range from 2 nm to 20 nm. In one or more of the foregoing and following embodiments, a thickness of the second coating layer is in a range from 2 nm to 10 nm. In one or more of the foregoing and following embodiments, a thickness of the second coating layer is not uniform. In one or more of the foregoing and following embodiments, the plurality of nanotubes includes single wall carbon nanotubes. In one or more of the foregoing and following embodiments, the plurality of nanotubes includes multi wall carbon 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 nanotubes, each of the plurality of nanotubes is covered by a first coating layer made of silicide or silicide-nitride, and a nano-particle is disposed on the plurality of nanotubes or over the first coating layer. In one or more of the foregoing and following embodiments, the nano-particle includes at least one selected from the group consisting of Mo2C, MoC, MoN, Ru and RuO2. In one or more of the foregoing and following embodiments, a size of the nano-particle is in a range from 1 nm to 5 nm. In one or more of the foregoing and following embodiments, a second coating layer is disposed over the first coating layer. In one or more of the foregoing and following embodiments, the second coating layer includes one of AlN, TiN or SiC. In one or more of the foregoing and following embodiments, the first coating layer includes one or more of ZrSi, MoSi, NbSi, ZrSiN, MoSiN or NbSiN. In one or more of the foregoing and following embodiments, the plurality of nanotubes include a 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 a 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 a 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 a 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 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 first coating layer made of silicide or a silicide-nitride is formed over each of the plurality of nanotubes. In one or more of the foregoing and following embodiments, when the first coating layer is formed, a metal containing layer is formed over the plurality of nanotubes, a silicon containing layer is formed over the metal containing layer, and a heating operation is performed to form an alloy of a metal containing in the metal containing layer and silicon in the silicon containing layer. In one or more of the foregoing and following embodiments, the heating operation is performed at a temperature in a range from 200° C. to 1000° C. In one or more of the foregoing and following embodiments, the heating operation is performed for 5 min to 60 min. In one or more of the foregoing and following embodiments, the metal containing layer and the silicon containing layer are formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD), respectively. In one or more of the foregoing and following embodiments, the heating operation is performed by applying a current to the nanotube layer. In one or more of the foregoing and following embodiments, the heating operation is performed under a pressure in a range from 10−2 Torr to 10−7 Torr. In one or more of the foregoing and following embodiments, the heating operation is performed in an N2, NH3, He, or Ar ambient without oxidizing gas. In one or more of the foregoing and following embodiments, a second coating layer is formed over the first coating layer. In one or more of the foregoing and following embodiments, the second coating layer includes one of AlN, TiN or SiC. In one or more of the foregoing and following embodiments, the first coating layer includes silicide or silicide nitride of one or more of Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Jr or Rh.
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 coating layer containing Si and one or more transition metals is formed over the plurality of nanotubes by atomic layer deposition (ALD). In one or more of the foregoing and following embodiments, the ALD comprises supplying a Zr containing precursor and supplying a Si containing precursor. In one or more of the foregoing and following embodiments, the Zr containing precursor is zirconium tetra-tert-butoxide (Zr[OC(CH3)3]4) and the Si containing precursor is SiCl4. In one or more of the foregoing and following embodiments, the Zr containing precursor is ZrCl4 and the Si containing precursor is tetra butyl orthosilicate. In one or more of the foregoing and following embodiments, a deposition temperature of the ALD is in a range from 100° C. to 500° C. In one or more of the foregoing and following embodiments, the ALD is performed under a pressure in a range from 10−2 Torr to 10−7 Torr. In one or more of the foregoing and following embodiments, in the ALD, each of the Zr precursor and the Si precursor is supplied as a gas pulse of 0.01 sec to 5 sec. In one or more of the foregoing and following embodiments, a heating operation is performed to form an alloy of Si and the one or more transition metal.
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, a plurality of nano-particles are formed over the plurality of nanotubes, and a first coating layer made of silicide or a silicide-nitride is formed over the plurality of nanotubes. In one or more of the foregoing and following embodiments, the plurality of nano-particles are formed after the first coating layer is formed. In one or more of the foregoing and following embodiments, the plurality of nano-particles include at least one selected from the group consisting of Mo2C, MoC, MoN, Ru and RuO2. In one or more of the foregoing and following embodiments, a size of the plurality of nano-particles is in a range from 1 nm to 5 nm. In one or more of the foregoing and following embodiments, a second coating layer is formed over the first coating layer. In one or more of the foregoing and following embodiments, the second coating layer includes one of AlN, TiN or SiC. In one or more of the foregoing and following embodiments, the first coating layer includes silicide or silicide nitride of one or more of Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Jr or Rh.
In accordance with another aspect of the present disclosure, in a method of manufacturing a pellicle for an extreme ultraviolet (EUV) reflective mask, a plurality of nanotube sheets, each including a plurality of nanotubes, are formed. Each of the plurality of nanotubes has a first coating layer. The plurality of nanotube sheets are stacked over a pellicle frame. In one or more of the foregoing and following embodiments, the first coating layer includes silicide or silicide nitride of one or more of Zr, Ti, Mn, Fe, Ru, Ni, Pd, Co, Mo, Nb, Jr or Rh. In one or more of the foregoing and following embodiments, a second coating layer is formed over the first coating layer. In one or more of the foregoing and following embodiments, the second coating layer includes one of AlN, TiN or SiC. In one or more of the foregoing and following embodiments, the plurality of nanotubes of one nanotube sheet are arranged along a first axis and the plurality of nanotubes of another nanotube sheet attached to the one nanotube sheet are arranged along a second axis, and the one nanotube sheet and the another nanotube sheet 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 one nanotube sheet have angles of ±15 degrees with respect to the first axis, when each of the plurality of nanotubes of the one nanotube sheet is subjected to linear approximation, and more than 90% of the plurality of nanotubes of the another nanotube sheet have angles of ±15 degrees with respect to the second axis, when each of the plurality of nanotubes of the another nanotube sheet 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.
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 claims priority of U.S. Provisional Patent Application No. 63/408,502 filed on Sep. 21, 2022, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63408502 | Sep 2022 | US |
