Thin film, thin film-photomask structure and method of forming semiconductor device

Abstract

The invention relates to a thin film, a thin film-photomask structure and a method of forming a semiconductor device. Provided is a thin film including a thin film film having improved stability to hydrogen plasma. The thin film film includes a network of a plurality of carbon nanotubes. At least one of the plurality of carbon nanotubes is surrounded by a multilayer protective coating including a stress control layer and a hydrogen permeation barrier layer over the stress control layer. The stress control layer and the hydrogen permeation barrier layer each include a Me-containing nitride or a Me-containing oxynitride, Me being selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr, and combinations thereof. The Me-containing nitride or Me-containing oxynitride in the stress control layer has a first Me concentration, the Me-containing nitride or Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration, and the second Me concentration is smaller than the first Me concentration.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and more particularly to a pellicle, a pellicle-photomask structure, and a method of forming a semiconductor device. Background Art

[0002] In the semiconductor integrated circuit (IC) industry, technological advances in IC materials and design have produced several generations of ICs, each with smaller and more complex circuits than the previous generation. In the course of IC development, functional density (i.e., the number of connected devices per chip area) has generally increased, while geometric size (i.e., the smallest component (or line) that can be manufactured using a manufacturing process) has decreased. This shrinking process generally provides benefits by increasing production efficiency and reducing associated costs. This shrinking also increases the complexity of IC processing and manufacturing.

[0003] In the process of manufacturing IC devices, a photolithography process is used to form a circuit pattern on a wafer. In the photolithography process, a photomask is used to transfer the desired pattern to the wafer. When the photomask is contaminated by foreign matter (e.g., particles) from the surrounding environment, defects may occur on the wafer where the pattern of the photomask is transferred. Summary of the invention

[0004] According to one aspect of the present application, a thin film is provided, comprising: a thin film film comprising a network of multiple carbon nanotubes, wherein at least one of the multiple carbon nanotubes is surrounded by a multi-layer protective coating, the multi-layer protective coating comprising: a stress control layer; and a hydrogen permeation barrier layer located on the stress control layer, wherein the stress control layer and the hydrogen permeation barrier layer each comprise a Me-containing nitride or a Me-containing oxynitride, Me being selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr and a combination thereof, wherein the Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration, which is less than the first Me concentration; a thin film border attached to the thin film film along a peripheral area of ​​the thin film film; and a thin film frame attached to the thin film border.

[0005] In some implementations, the first Me concentration is in a range from about 80 atomic % to about 98 atomic %.

[0006] In some implementations, the nitrogen concentration or the oxygen concentration of the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer is in a range from about 10 atomic % to about 50 atomic %.

[0007] In some implementations, the stress control layer includes SiN having a Si concentration in a range of about 80 atomic % to about 98 atomic %, and wherein the hydrogen permeation barrier layer includes SiN having a N concentration in a range of about 10 atomic % to about 50 atomic %.

[0008] In some implementations, the stress control layer includes SiON having a Si concentration in a range of about 80 atomic % to about 98 atomic %, and wherein the hydrogen permeation barrier layer includes SiON having a N concentration in a range of about 10 atomic % to about 50 atomic %.

[0009] In some implementations, the multi-layer protective coating further includes an interdiffusion layer between the stress control layer and the hydrogen permeation barrier layer.

[0010] In some implementations, the interdiffusion layer includes a Me-containing nitride or a Me-containing oxynitride, Me being selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr, and combinations thereof, wherein the Me-containing nitride or the Me-containing oxynitride in the interdiffusion layer has a third Me concentration, which is less than the first Me concentration but greater than the second Me concentration.

[0011] In some implementations, Me in the Me-containing nitride or the Me-containing oxynitride of the interdiffusion layer has a concentration gradient, wherein Me decreases in a direction from the stress control layer to the hydrogen permeation barrier layer.

[0012] In some implementations, the thin film membrane further includes a hydrogen reduction layer including a plurality of nanostructures in contact with at least one carbon nanotube of the plurality of carbon nanotubes.

[0013] In some implementations, the hydrogen reduction layer includes a metal selected from the group consisting of Ru, Mo, Zr, Ir, Pt, Rh, Nb, Ti, Cr, W, Al, Co, and Fe.

[0014] In some implementations, the thin film membrane further includes: a diffusion inhibitor layer located above the plurality of nanostructures and on at least one carbon nanotube in the plurality of carbon nanotubes.

[0015] In some implementations, the diffusion inhibitor layer includes Y2O3, Al2O3, TiO2, HfO2, or a combination thereof.

[0016] According to one aspect of the present application, a thin film-photomask structure is provided, comprising: a thin film, comprising a thin film film, the thin film film comprising a network of multiple carbon nanotubes, wherein at least one carbon nanotube among the multiple carbon nanotubes is surrounded by a multi-layer protective coating, the multi-layer protective coating comprising: a stress control layer; a hydrogen permeation barrier layer, located on the stress control layer; and an interdiffusion layer, located between the stress control layer and the hydrogen permeation barrier layer, wherein the stress control layer, the hydrogen permeation barrier layer and the interdiffusion layer each comprise a Me-containing nitride or a Me-containing oxynitride, Me being Si or a transition metal, wherein the Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration less than the first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the interdiffusion layer has a third Me concentration less than the first Me concentration but greater than the second Me concentration; and a photomask.

[0017] In some implementations, the transition metal is selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, and Cr.

[0018] In some implementations, the first Me concentration is in a range from about 80 atomic % to about 98 atomic %.

[0019] In some implementations, the first Me concentration, the second Me concentration, and the third Me concentration are not less than 50 atomic %.

[0020] In some implementations, the stress control layer and the hydrogen permeation barrier layer each have a thickness in a range of 0.5 nm to 10 nm.

[0021] According to one aspect of the present application, a method for forming a semiconductor device is provided, comprising: providing extreme ultraviolet (EUV) light to a photomask through a thin film on a photomask, wherein the thin film comprises a thin film membrane having a network of multiple carbon nanotubes, wherein at least one of the multiple carbon nanotubes is surrounded by a multi-layer protective coating, the multi-layer protective coating comprising: a stress control layer; and a hydrogen permeation barrier layer located on the stress control layer, wherein the stress control layer and the hydrogen permeation barrier layer each comprise a Me-containing nitride or a Me-containing oxynitride, Me being selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr and combinations thereof, wherein the Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration less than the first Me concentration; and directing a portion of the EUV light reflected from the photomask onto a photoresist layer on a substrate.

[0022] In some implementations, the first Me concentration is in a range from about 80 atomic % to about 98 atomic %.

[0023] In some implementations, the method further includes developing the photoresist layer to form a patterned photoresist layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] When read in conjunction with the accompanying drawings, various aspects of the present disclosure can be best understood from the following detailed description. Note that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the size of various features may be arbitrarily increased or reduced for clarity of discussion.

[0025] Figure 1 is a schematic diagram of a lithography system according to some embodiments.

[0026] Figure 2A is a cross-sectional view of a pellicle-photomask structure according to some embodiments.

[0027] Figure 2B According to some embodiments Figure 2A Isometric view of the pellicle-photomask structure.

[0028] Figure 2C According to some embodiments Figure 2A and Figure 2B Top view of the pellicle membrane.

[0029] Figure 2D According to some embodiments Figure 2C A cross-sectional view of the coated carbon nanotubes of the carbon nanotube network is shown.

[0030] Figure 3A-Figure 3L According to some embodiments Figure 2D Cross-sectional views of various examples of multi-layer protective coatings are shown.

[0031] Figure 4 is a flow chart illustrating a method for assembling a thin film for a photolithography process according to some embodiments.

[0032] Figure 5 is a flow chart illustrating a method of forming a protective coating on carbon nanotubes according to some embodiments.

[0033] Figure 6A-6F According to some embodiments Figure 5 Cross-sectional views of the protective coating at different stages of the process.

[0034] Figure 7 is a flow chart illustrating a method of forming a protective coating on carbon nanotubes according to some embodiments.

[0035] Figure 8A-8F According to some embodiments Figure 7Cross-sectional views of the protective coating at different stages of the process.

[0036] Fig. 9 is a flow chart illustrating a method of manufacturing a semiconductor device according to some embodiments.

[0037] Figures 10A-10D According to some embodiments Fig. 9 Cross-sectional views of a semiconductor device at different stages of a method. DETAILED DESCRIPTION

[0038] The following disclosure provides many different embodiments or examples for implementing the different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify this description. Of course, these are merely examples and are not intended to be limiting. For example, in the following description, forming a first feature on or on a second feature may include an embodiment in which the first feature and the second feature are formed in direct contact, and may also include an embodiment in which additional features may be formed between the first feature and the second feature so that the first feature and the second feature may not be in direct contact. In addition, the present disclosure may repeat reference numbers and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or configurations discussed.

[0039] Additionally, spatially relative terms (e.g., "below," "beneath," "below," "above," "upper," etc.) may be used herein to facilitate describing the relationship of one element or feature illustrated in the figures relative to another element(s) or feature(s). These 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 interpreted accordingly.

[0040] The photolithography patterning process uses a photomask that includes the desired mask pattern. The photomask can be a reflective mask or a transmissive mask. During this process, ultraviolet light is reflected from the surface of the photomask (for a reflective mask) or transmitted through the photomask (for a transmissive mask) to transfer the pattern to a photoresist on a semiconductor wafer. The exposed portion of the photoresist is photochemically modified. After exposure, the photoresist is developed to define openings in the photoresist, and one or more semiconductor process steps (such as etching, epitaxial layer deposition, metallization, etc.) are performed, which operate on the areas of the wafer surface exposed by the openings in the photoresist. After the semiconductor process is completed, the photoresist is removed by a suitable resist stripper, etc.

[0041] The minimum feature size of the pattern is limited by the wavelength of light. Deep ultraviolet (UV) lithography (for example, using a wavelength of 193nm or 248nm in some standard deep UV platforms) typically uses a transmission mask and provides a smaller minimum feature size than longer wavelength lithography. Extreme ultraviolet (EUV) light (across wavelengths of 124nm to 10nm) is currently being used to provide even smaller minimum feature sizes. At shorter wavelengths, particulate contaminants on the photomask can cause defects in the transferred pattern. Therefore, a thin film is used to protect the photomask from such particulate contaminants. The thin film includes a thin film film that is attached to a mounting frame. The mounting frame supports the thin film film on the photomask. Any contamination particles that fall on the thin film film will be blocked outside the focal plane of the photomask. Therefore, defects in the transferred pattern are reduced or avoided.

[0042] Since the pellicle film remains covering the photomask during exposure, it is subject to stringent requirements in terms of absorption, durability, and particle shielding capability. In the field of EUV lithography, finding a suitable pellicle film material with high transmittance and high stability at EUV wavelengths has become a challenge.

[0043] Carbon nanotubes (CNTs) are one of the materials suitable for pellicle membranes in EUV reflective photomasks. CNTs have high EUV transmittance and mechanical stability, while having low EUV scattering and reflectivity. However, during EUV lithography, the pellicle membrane may be exposed to hydrogen plasma, which poses a challenge because the original CNT is easily damaged by hydrogen plasma due to the presence of crystal defects on the CNT surface. This damage can potentially shorten the service life of the pellicle membrane.

[0044] The embodiments of the present disclosure provide CNTs with enhanced resistance to hydrogen plasma etching by forming a multilayer protective coating around the CNT core as a shell. The multilayer protective coating includes layers of different materials, each layer is used for different functions, and together produce a synergistic effect of reducing the flow of hydrogen ions to the surface of the CNT. Therefore, the damage caused to the CNT by hydrogen plasma etching is reduced. The thin film formed by these coated CNTs has improved reliability and extended service life. In an embodiment of the present disclosure, the thin film is formed by a network of multiple CNTs. Within the network, at least one CNT is coated with a multilayer protective coating, and the multilayer protective coating includes a stress control layer and a hydrogen permeation barrier layer. The hydrogen permeation barrier layer is configured to prevent the passage of hydrogen ions, thereby reducing the damage of the CNT to hydrogen plasma during EUV exposure. The stress control layer is configured to minimize the formation of defects and cracks in the hydrogen permeation barrier layer, thereby reducing the penetration of hydrogen ions. Optionally, the multi-layer protective coating may include: a hydrogen reduction layer including a plurality of nanostructures that are capable of reacting with hydrogen ions to further mitigate damage to CNTs by hydrogen plasma during EUV exposure; and a diffusion suppression layer to prevent aggregation of these hydrogen reduction nanostructures, thereby maintaining EUV transmittance of the thin film film. Thus, such a thin film film has improved etching resistance, high EUV transmittance, and enhanced durability.

[0045] Figure 1 1 is a schematic diagram of a lithography system 100 according to some embodiments. The lithography system 100 may also be generally referred to as a "scanner" and may be operable to perform a lithography process, including exposure using a corresponding radiation source and in a specific exposure mode.

[0046] In some embodiments, the lithography system 100 includes a high brightness light source 102, an illuminator 104, a mask stage 106, a photomask 108, a projection optical module 110, and a substrate stage 112. In some embodiments, the lithography system 100 may include Figure 1 In some embodiments, one or more of the high brightness light source 102, the illuminator 104, the mask stage 106, the photomask 108, the projection optics module 110, and the substrate stage 112 may be omitted from the lithography system 100 or may be integrated into a combined assembly.

[0047] The high brightness light source 102 may be configured to emit radiation having a wavelength in the range of about 1 nanometer (nm) to 250 nm. In some embodiments, the high brightness light source 102 generates EUV light centered at a wavelength of about 13.5 nm; therefore, in some embodiments, the high brightness light source 102 may also be referred to as an "EUV light source". However, it will be understood that the high brightness light source 102 should not be limited to emitting EUV light. For example, the high brightness light source 102 may be used to emit any high intensity photons from an excited target material.

[0048] In embodiments where the lithography system 100 is a UV lithography system, the illuminator 104 may include various refractive optical components, such as a single lens or a lens system including multiple lenses (zone plates). In embodiments where the lithography system 100 is an EUV lithography system, the illuminator 104 may include various reflective optical components, such as a single mirror or a mirror system including multiple mirrors. The illuminator 104 may direct light from the high brightness light source 102 onto the mask stage 106, and more specifically, onto the photomask 108 fixed to the mask stage 106. In embodiments where the high brightness light source 102 generates light in the EUV wavelength range, the illuminator 104 includes reflective optics.

[0049] The mask stage 106 may be configured to hold the photomask 108. In some embodiments, the mask stage 106 may include an electrostatic chuck (e-chuck) to hold the photomask 108. This is because gas molecules absorb EUV light, and the lithography system 100 for EUV lithography patterning is maintained in a vacuum environment to minimize EUV intensity loss. In this document, the terms "photomask", "mask" and "reticle" are used interchangeably. In one example, the photomask 108 is a reflective mask.

[0050] In some embodiments, a membrane 114 may be placed over the photomask 108, for example, between the photomask 108 and the substrate stage 112. The membrane 114 may protect the photomask 108 from particles and may defocus the particles so that the particles do not create an image that may cause defects on the wafer during the photolithography process.

[0051] The projection optics module 110 can be configured to image the pattern of the photomask 108 onto a semiconductor wafer 116 fixed to a substrate stage 112. In some embodiments, the projection optics module 110 includes a refractive optical device (e.g., for a UV lithography system). In some embodiments, the projection optics module 110 includes a reflective optical device (e.g., for an EUV lithography system). The projection optics module 110 can collect light directed from the photomask 108, which carries an image of the pattern defined on the photomask 108. The illuminator 104 and the projection optics module 110 can be collectively referred to as an "optical module" of the lithography system 100.

[0052] In some embodiments, semiconductor wafer 116 may be a bulk semiconductor wafer. For example, semiconductor wafer 116 may include a silicon wafer. Semiconductor wafer 116 may include silicon or another elemental semiconductor material, such as germanium. In some embodiments, semiconductor wafer 116 may include a compound semiconductor. The compound semiconductor may include gallium arsenide, silicon carbide, indium arsenide, indium phosphide, another suitable material, or a combination thereof.

[0053] In some embodiments, semiconductor wafer 116 includes a silicon-on-insulator (SOI) substrate. The SOI substrate may be fabricated using a separation by implantation of oxygen (SIMOX) process, a wafer bonding process, another suitable process, or a combination thereof.

[0054] In some embodiments, semiconductor wafer 116 includes an undoped substrate. However, in other embodiments, semiconductor wafer 116 includes a doped substrate, for example, a p-type substrate or an n-type substrate.

[0055] In some embodiments, according to the design requirements of the semiconductor device structure, the semiconductor wafer 116 includes various doped regions (not shown). The doped regions may include, for example, a p-type well and / or an n-type well. In some embodiments, the doped regions are doped with p-type dopants. For example, the doped regions may be doped with boron or boron fluoride. In other embodiments, the doped regions are doped with n-type dopants. For example, the doped regions may be doped with phosphorus or arsenic. In some embodiments, some doped regions are p-doped and other doped regions are n-doped.

[0056] In some embodiments, an interconnect structure may be formed over semiconductor wafer 116. The interconnect structure may include multiple interlayer dielectric layers, including dielectric layers. The interconnect structure may also include multiple conductive features formed in the interlayer dielectric layers. The conductive features may include conductive lines, conductive vias, and / or conductive contacts.

[0057] In some embodiments, various device elements are formed in the semiconductor wafer 116. Examples of various device elements may include transistors (e.g., metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJTs), high voltage transistors, high frequency transistors, p-channel and / or n-channel field effect transistors (PFETs and / or NFETs)), diodes, or other suitable elements. Various processes may be used to form the various device elements, including deposition, etching, implantation, photolithography, annealing, and / or other suitable processes.

[0058] The device elements may be interconnected to form an integrated circuit device through an interconnect structure on the semiconductor wafer 116. The integrated circuit device may include a logic device, a memory device (e.g., a static random access memory (SRAM) device), a radio frequency (RF) device, an input / output (I / O) device, a system on a chip (SoC) device, an image sensor device, other applicable devices, or a combination thereof.

[0059] In some embodiments, semiconductor wafer 116 may be coated with a photoresist layer that is sensitive to EUV light. Various components including the above items may be integrated together and may be operated to perform a photolithography exposure process.

[0060] Figure 2Ais a cross-sectional view of a pellicle-photomask structure 200 according to some embodiments of the present disclosure. Figure 2B yes Figure 2A An isometric view of the film-photomask structure 200. Figure 2A and Figure 2B As shown, the photomask 108 may include a mask substrate 202 and a mask pattern 204 disposed on the mask substrate 202 .

[0061] In some embodiments, the mask substrate 202 includes a transparent substrate, such as relatively defect-free fused quartz, borosilicate glass, soda-lime glass, calcium fluoride, low thermal expansion material, ultra-low thermal expansion material, or other suitable material. The mask pattern 204 can be placed on the mask substrate 202 as described above, and can be designed according to the integrated circuit features to be formed on the semiconductor wafer (e.g., Figure 1 The mask pattern 204 may be formed by depositing a material layer and patterning the material layer to have one or more openings and one or more absorption regions, wherein the radiation beam may pass through the openings without being absorbed, and the absorption regions may completely or partially block the radiation beam.

[0062] The mask pattern 204 may include metal, metal alloy, metal silicide, metal nitride, metal oxide, metal oxynitride, or other applicable materials. Examples of materials that can be used to form the mask pattern 204 include, but are not limited to, Cr, Mo, x Si y 、 x Si y 、Mo、Nb x O y 、Ti、Ta、Cr x N y 、Mo x O y 、Mo x N y Cr x O y 、Ti x N y 、Zr x N y 、Ti x O y 、 x N y 、 x O y 、Si x O y , Nb x N y 、Zr x N y 、Al x Oy N z 、 x B y O z 、 x B y N z 、Ag x O y 、Ag x N y ,Ni,Ni x O y 、Ni x O y N z Etc. The ratio of compound x / y / z is not limited.

[0063] In some embodiments, the photomask 108 is an EUV mask. However, in some other embodiments, the photomask 108 may be an optical mask.

[0064] like Figure 2A and Figure 2B As shown, the membrane 114 may be placed on the photomask 108. The membrane 114 and the photomask 108 may form a closed internal volume 228 surrounded by the membrane 114 and the photomask 108. The membrane 114 and the photomask 108 separate the internal volume 228 from the external environment 229. In some embodiments, the membrane 114 includes a membrane frame 206, which may be placed on at least one of the mask substrate 202 and the mask pattern 204. In some embodiments, the membrane frame 206 may be formed of Si, SiC, SiN, glass, a low thermal expansion coefficient material (such as Al alloy, Ti alloy, Invar, Kovar, etc.), another suitable material, or a combination thereof. In some embodiments, a suitable process for forming the membrane frame 206 may include a machining process, a sintering process, a photochemical etching process, other applicable processes, or a combination thereof.

[0065] In some embodiments, film frame 206 may include side 208 having inner surface 210 and outer surface 212, wherein inner surface 210 and outer surface 212 are located on opposite sides of side 208. Film frame 206 may also include bottom surface 214 or base connecting inner surface 210 and outer surface 212.

[0066] like Figure 2A and Figure 2BAs further shown, the film-photomask structure 200 may further include a vent structure 216 formed in the side 208 and extending through from the inner surface 210 to the outer surface 212. In some embodiments, the vent structure 216 may include one or more holes formed in the side 208 of the film frame 206. The holes may take any shape, including circular holes, rectangular holes, slit-shaped holes, other shapes, or any combination thereof. The holes may allow airflow through a portion of the film-photomask structure 200. In some embodiments, the vent structure 216 of the film frame 206 may be formed such that at least one side 208 of the film frame 206 includes one hole formed in the top of the side 208 (e.g., near the frame 224) and another hole formed in the bottom of the side 208 (e.g., near the mask pattern 204). In some embodiments, the holes may include a filter to minimize the passage of foreign particles through the vent structure 216.

[0067] In some embodiments, where the vent structure comprises a filter, the vent structure 216 can be formed together with the membrane frame 206. In some embodiments, the vent structure 216 can be formed using a photochemical etching process, another suitable process, or a combination thereof.

[0068] In some other embodiments, where the vent structure includes a filter, the vent structure 216 and the membrane frame 206 may be formed separately, and an opening (not shown) may be formed in the side 208 of the membrane frame 206. Thereafter, in some embodiments, the vent structure 216 may be placed into the opening in the side 208 of the membrane frame 206. The vent structure 216 may then be bonded to the membrane frame 206, for example, by a brazing process, a direct diffusion bonding process, a eutectic bonding process, another applicable process, or a combination thereof. In some embodiments, the vent structure 216 may prevent the membrane film 226 from cracking during the EUV lithography process.

[0069] like Figure 2A and Figure 2B As further shown, the pellicle-photomask structure 200 may further include a pellicle frame adhesive 218 disposed between the pellicle frame 206 and the mask substrate 202 .

[0070] In some embodiments, the film frame adhesive 218 may be formed of a cross-linking type adhesive, a thermoplastic elastomer type adhesive, a polystyrene type adhesive, an acrylic type adhesive, a silicon-based adhesive, an epoxy type adhesive, or a combination thereof.

[0071] In some embodiments, the film frame 206 may be surface treated to enhance the adhesion of the film frame 206 to the film frame adhesive 218. In some embodiments, the surface treatment may include an oxygen plasma treatment, another suitable treatment, or a combination thereof. However, in other embodiments, the film frame 206 may not be surface treated.

[0072] The pellicle-photomask structure 200 may further include a pellicle film adhesive 220 disposed on the pellicle frame 206. In some embodiments, the pellicle film adhesive 220 may be formed of a thermoplastic elastomer-based adhesive, a polystyrene-based adhesive, an acrylic-based adhesive, a silicone-based adhesive, an epoxy-based adhesive, another suitable adhesive, or a combination thereof. In some embodiments, the pellicle film adhesive 220 may be formed of a material different from the material constituting the pellicle frame adhesive 218.

[0073] like Figure 2A and Figure 2B As further shown, the pellicle-photomask structure 200 may further include a pellicle assembly 222 placed over the pellicle frame 206 and the pellicle film adhesive 220. As shown, the pellicle film adhesive 220 may be placed between the pellicle assembly 222 and the pellicle frame 206.

[0074] In some embodiments, the thin film assembly 222 may include a frame 224 placed on the thin film adhesive 220, and a thin film 226 placed on the frame 224. In some embodiments, the frame 224 may be formed by Si. In further embodiments, the frame 224 may be formed by boron carbide, graphene, carbon nanotubes, SiC, SiN, SiO2, SiON, Zr, Nb, Mo, Cd, Ru, Ti, Al, Mg, V, Hf, Ge, Mn, Cr, W, Ta, Ir, Zn, Cu, F, Co, Au, Pt, Sn, Ni, Te, Ag, another suitable material, an allotrope of any of these materials, or a combination thereof. The frame 224 may mechanically support the thin film 226 around the periphery of the thin film 226. When the thin film-photomask structure 200 is fully assembled, the frame 224 may be mechanically supported by the thin film frame 206. That is, the pellicle frame 206 may mechanically support the frame 224 and the pellicle film 226 of the pellicle film assembly 222 on the photomask 108 .

[0075] In some embodiments, the thin film film 226 can be formed by a network of multiple CNTs. The CNTs can be single-walled CNTs (SWCNTs), double-walled CNTs (DWCNTs), multi-walled CNTs (MWCNTs), or a combination thereof. The wall thickness of the CNTs can be in the range of about 0.01 nm to about 100 nm. The CNTs in the thin film film 226 can be individual non-bundled CNTs or bundled individual CNTs. Bundled individual CNTs form a CNT bundle. The term "CNT bundle" refers to more than 10 individual CNTs entangled with each other. Although not limited by theory, in certain embodiments, a CNT bundle can be formed by up to 20 CNTs. For example, Figure 2C Shows Figure 2A and Figure 2B An example of a thin film membrane 226. Figure 2C In the example shown, the thin film film 226 includes a CNT film layer formed of randomly oriented CNTs 230. In some embodiments, the thin film film 226 has a multilayer structure including multiple CNT film layers. In some embodiments, each of the multiple CNT film layers is formed of randomly oriented CNTs. In other embodiments, the multiple CNT film layers are formed of oriented CNTs, wherein the CNTs in adjacent layers are arranged at a certain angle relative to each other.

[0076] In some embodiments, the structural density of the network of CNTs 230 that make up the thin film film 226 can be between 0.2 and 1, depending on the desired percentage of radiation transmitted by the thin film film 226. For example, the thin film film 226 has been demonstrated to achieve light transmittances up to about 90%. The precise structural density can be selected to maximize EUV radiation transmittance while minimizing particle penetration through the thin film film 226. For example, while a looser structural density can achieve higher EUV radiation transmittance, a looser structural density can also allow particles to penetrate the photomask 108.

[0077] In some embodiments, the thickness of the thin film 226 may be between 10 nm and 100 nm. In more specific embodiments, the thickness of the thin film 226 is between 20 nm and 50 nm. These ranges have been found to provide sufficient robustness for the thin film 226 while also providing high EUV transmittance. Generally, the thicker the thin film 226, the more robust the thin film 226; however, if the thin film 226 is too thick, the percentage of EUV transmission may be reduced. Therefore, the disclosed range strikes a balance between these two goals.

[0078] CNTs are susceptible to degradation due to exposure to hydrogen plasma (e.g., the type employed during operation or maintenance of a lithography system). In order to extend the useful life of CNT thin film films in the scanning environment of EUV-induced hydrogen-based plasmas, in embodiments of the present disclosure, one or more CNTs in a network of multiple CNTs are coated with a protective coating. For example, in some embodiments, more than 90% of the individual CNTs in a network of multiple CNTs are coated with a protective coating. In some embodiments, more than 95%, more than 98%, or 100% of the individual CNTs in a network of multiple CNTs are coated with a protective coating. For example, Figure 2D Shows Figure 2C A side cross-sectional view of a CNT 230 in a network of multiple CNTs is shown. Figure 2D As shown, CNT 230 is coated with protective coating 240 to provide coated CNT (e.g., coated CNT 300, Figure 3A-Figure 3L ). The coated CNT has a core-shell structure, including a CNT core and a protective coating shell. In an embodiment of the present disclosure, the protective coating 240 is characterized by a multilayer structure, including two or more layers of different materials, each layer having a different function to prevent hydrogen plasma from damaging the CNT 230, as described in detail below.

[0079] In some embodiments, the total thickness of the protective coating layer 240 is in the range of about 1 nm to about 40 nm. When the thickness of the protective coating layer 240 is greater than this range, the EUV transmittance of the thin film 226 may be reduced, and when the thickness of the protective coating layer is less than this range, the mechanical strength of the thin film 226 may be insufficient.

[0080] Figure 3A-Figure 3L is a cross-sectional view showing various examples of coated CNTs 300 in a network of multiple CNTs according to embodiments of the present disclosure. Figure 3A-Figure 3L The depicted coated CNTs 300 differ from one another based on the composition of the protective coating 240 surrounding the CNTs 230 .

[0081] Figure 3A is a cross-sectional view of a first example of a coated CNT 300 in a network of a plurality of CNTs 230 according to some embodiments. Figure 3A As shown, the protective coating 240 surrounding the CNT 230 has a double-layer structure including a stress control layer 242 on the CNT 230 and a hydrogen permeation barrier layer 244 on the stress control layer 242 .

[0082] The stress control layer 242 is in physical contact with the outer surface of the CNT 230 and is adapted to reduce the stress between the CNT 230 and the hydrogen permeation barrier layer 244, thereby inhibiting the formation of cracks and / or defects in the hydrogen permeation barrier layer 244. In some embodiments, the stress control layer 242 may include a metal-rich metal nitride or a silicon-rich silicon nitride, the metal or silicon content of which is in the range of about 80 atomic (at) % to about 98 at %. In some embodiments, the metal is a transition metal selected from Ti, Y, Hf, Zr, Zn, Mo, Cr, and combinations thereof. The metal-rich or silicon-rich nitride is represented by the formula MeN, wherein Me is Si or a transition metal selected from Ti, Y, Hf, Zr, Zn, Mo, Cr, and combinations thereof, and the content of Me in MeN is about 80 at % to about 98 at %. In some embodiments, the stress control layer 242 may include a metal-rich metal oxynitride or a silicon-rich silicon oxynitride, the metal or silicon content of which is in the range of about 80 at % to about 98 at %. In some embodiments, the metal is a transition metal selected from Ti, Y, Hf, Zr, Zn, Mo, Cr, and combinations thereof. The metal-rich or silicon-rich oxynitride is represented by the formula MeON, wherein Me is Si or a transition metal selected from Ti, Y, Hf, Zr, Zn, Mo, Cr, and combinations thereof, and the content of Me in MeN is about 80 at % to about 98 at %.

[0083] The stress control layer 242 is relatively thin, so as not to reduce the transparency of the thin film film 226 to EUV light. In some embodiments, the thickness of the stress control layer 242 can be in the range of about 0.5 nm to about 10 nm. The stress control layer 242 can be formed by a suitable deposition technique, for example, chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), atomic layer deposition (ALD), plasma enhanced ALD (PEALD), physical vapor deposition (PVD), or other suitable techniques. In some embodiments, the stress control layer 242 is formed as a conformal layer around the CNT 230.

[0084] The hydrogen permeation barrier layer 244 is in physical contact with the stress control layer 242 and is suitable for preventing or hindering hydrogen ions from passing through the layer, thereby preventing hydrogen plasma from damaging the CNTs. In some embodiments, the hydrogen permeation barrier layer 244 is a nitride layer rich in nitrogen (N) or oxygen (O), or an oxynitride layer rich in N or O. As used herein, the term "rich in N or O" means that the content of N or O in the nitride or oxynitride constituting the hydrogen permeation barrier layer 244 is greater than the content of N or O in the nitride or oxynitride constituting the stress control layer 242. In some embodiments, the hydrogen permeation barrier layer 244 includes a silicon or metal nitride rich in N or O (represented by MeN, Me is Si or a transition metal) or a silicon or metal oxynitride rich in N or O (represented by MeON, Me is Si or a transition metal), wherein the content of N or O is in the range of about 10 at% to about 50 at%. In some embodiments, the metal is a transition metal selected from Ti, Y, Hf, Zr, Zn, Mo, Cr and combinations thereof. In some embodiments, the hydrogen permeation barrier layer 244 includes N-rich silicon nitride (SiN) or silicon-rich oxynitride (SiON) having an N content in a range of about 10 at % to about 50 at %.

[0085] The hydrogen permeation barrier layer 244 is relatively thin, so it does not reduce the transparency of the thin film film 226 to EUV light. In some embodiments, the thickness of the hydrogen permeation barrier layer 244 can be in the range of about 0.5 nm to about 10 nm. The hydrogen permeation barrier layer 244 can be formed by a suitable deposition technique, for example, CVD, PECVD, ALD, PEALD, PVD or other suitable techniques. In some embodiments, the hydrogen permeation barrier layer 244 is formed as a conformal layer around the stress control layer 242.

[0086] In some embodiments, both the stress control layer 242 and the hydrogen permeation barrier layer 244 include SiN, but the contents of Si and N are different. For example, in some embodiments, the stress control layer 242 is a Si-rich layer composed of SiN, and its Si content is in the range of about 80at% to 90at%, while the hydrogen permeation barrier layer 244 is a N-rich layer composed of SiN, and its N content is in the range of about 10at% to 50at%. Therefore, the Si content of the stress control layer 242 is higher than that of the hydrogen permeation barrier layer 244.

[0087] In some embodiments, both the stress control layer 242 and the hydrogen permeation barrier layer 244 include SiON, but the contents of Si and N are different. For example, in some embodiments, the stress control layer 242 is a Si-rich layer composed of SiON, and its Si content is in the range of about 80at% to 90at%, while the hydrogen permeation barrier layer 244 is an N-rich layer composed of SiON, and its N content is in the range of about 10at% to 50at%. Therefore, the Si content of the stress control layer 242 is higher than that of the hydrogen permeation barrier layer 244.

[0088] Figure 3B is a cross-sectional view of a second example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3B As shown, the protective coating 240 surrounding the CNT 230 has a double-layer structure, which includes a hydrogen permeation barrier layer 244 on the CNT 230 and a stress control layer 242 on the hydrogen permeation barrier layer 244. Figure 3A Unlike the first example shown (in which the hydrogen permeation barrier layer 244 is the outermost layer of the protective coating 240), in this example, the hydrogen permeation barrier layer 244 is in physical contact with the outer surface of the CNT 230, and the stress control layer 242 is in physical contact with the hydrogen permeation barrier layer 244. Therefore, in this example, the stress control layer 242 is the outermost layer of the protective coating 240 and is formed after the hydrogen permeation barrier layer 244. The composition and properties of the corresponding hydrogen permeation barrier layer 244 and stress control layer 242 are the same as above. Figure 3A The above description remains the same and will not be repeated in detail here.

[0089] Figure 3C is a cross-sectional view of a third example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3C As shown, the protective coating 240 surrounding the CNT 230 has a three-layer structure, which includes a stress control layer 242 on the CNT 230, an interdiffusion layer 246 on the stress control layer 242, and a hydrogen permeation barrier layer 244 on the interdiffusion layer 246. Figure 3A Compared to the first example shown, in the present embodiment, the protective coating 240 includes an additional interdiffusion layer 246 disposed between the stress control layer 242 and the hydrogen permeation barrier layer 244 .

[0090] In some embodiments, the interdiffusion layer 246 includes a Si-rich or metal-rich nitride (represented by MeN, Me is Si or a transition metal), or a Si-rich or metal-rich oxynitride (represented by MeON, Me is Si or a transition metal). In some embodiments, the metal is a transition metal selected from Ti, Y, Hf, Zr, Zn, Mo, Cr, and combinations thereof. Compared to the stress control layer 242 and the hydrogen permeation barrier layer 244, the amount of Si or metal contained in the interdiffusion layer 246 is lower than that in the stress control layer 242, but higher than that in the hydrogen permeation barrier layer 244. In some embodiments, the interdiffusion layer 246 may present a concentration gradient of Si or metal, wherein the concentration decreases in a direction from the stress control layer 242 to the hydrogen permeation barrier layer 244.

[0091] The interdiffusion layer 246 is thin and thus does not reduce the transparency of the thin film film 226 to EUV light. In some embodiments, the thickness of the interdiffusion layer 246 may be in the range of about 0.1 nm to about 5 nm. The interdiffusion layer 246 may be formed by thermal annealing, which diffuses silicon or metal atoms from the stress control layer 242 and the hydrogen permeation barrier layer 244 into the interdiffusion layer 246. In some embodiments, the annealing temperature may be in the range of about 200° C. to about 1000° C.

[0092] Figure 3D is a cross-sectional view of a fourth example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3D As shown, the protective coating 240 surrounding the CNT 230 has a three-layer structure, which includes a hydrogen permeation barrier layer 244 on the CNT 230, an interdiffusion layer 246 on the hydrogen permeation barrier layer 244, and a stress control layer 242 on the interdiffusion layer 246. Figure 3C Unlike the third example shown, in which the hydrogen permeation barrier layer 244 is the outermost layer of the protective coating 240 , in this example, the stress control layer 242 is the outermost layer of the protective coating 240 and is formed after the hydrogen permeation barrier layer 244 .

[0093] Figure 3E is a cross-sectional view of a fifth example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3E As shown, the protective coating 240 surrounding the CNT 230 has a three-layer structure, which includes a hydrogen reduction layer 248 on the CNT 230, a stress control layer 242 on the hydrogen reduction layer 248 and the CNT 230, and a hydrogen permeation barrier layer 244 on the stress control layer 242. Figure 3A Compared to the first example shown, in this embodiment, the protective coating 240 includes an additional hydrogen reduction layer 248 disposed on the surface of the CNT 230 .

[0094] The hydrogen reduction layer 248 is in physical contact with the CNT 230 and is adapted to reduce the amount of hydrogen ions reaching the CNT 230, thereby preventing the hydrogen plasma from causing damage to the CNT 230. In some embodiments, the hydrogen reduction layer 248 includes a metal capable of reacting with hydrogen radicals (hydrogen ions) to form hydrogen molecules (H+H=H2), thereby reducing the amount of hydrogen reaching the CNT 230. In some embodiments, the hydrogen reduction layer 248 includes a transition metal, such as Ru, Mo, Zr, Ir, Pt, Rh, Nb, Ti, Cr, W, Co, or Fe. In some embodiments, the hydrogen reduction layer 238 includes a Group 13 metal, such as Al or Ga.

[0095] The hydrogen reduction layer 248 can be formed as a continuous layer or a discontinuous layer. Since transition metals and Group 13 metals generally have high EUV absorptivity, a discontinuous layer is desirable because a continuous layer may reduce EUV transmittance. In some embodiments, the hydrogen reduction layer 248 may include a plurality of nanostructures 249 having a size in the nanometer range. In some embodiments, the size of the nanostructures 249 may be in the range of about 0.5 nm to about 6 nm. The nanostructures 249 may take any shape or geometry. For example, in some embodiments, the nanostructures 249 may be nanograins, nanoislands, nanocubes, or nanosheets. In some embodiments and as Figure 3E As shown, the hydrogen reduction layer 248 is a non-continuous layer including a plurality of nanocrystals embedded in the stress control layer 242. In some embodiments, the nanostructures 249 are uniformly distributed on the surface of the CNT 230. In some other embodiments, the nanostructures 249 are randomly distributed on the surface of the CNT 230. The spacing between adjacent nanostructures 249 is selected so that the nanostructures 249 will not block the transmission of EUV light while being able to react with hydrogen ions to prevent the hydrogen ions from etching the CNT 230.

[0096] In some embodiments, the hydrogen reduction layer 248 may be formed by sol-gel, E-beam evaporation, CVD, ALD, PEALD, electrodeposition, or electroless deposition.

[0097] Figure 3F is a cross-sectional view of a sixth example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3F As shown, the protective coating 240 surrounding the CNT 230 has a three-layer structure, which includes a hydrogen reduction layer 248 on the CNT 230, a hydrogen permeation barrier layer 244 on the hydrogen reduction layer 248 and the CNT 230, and a stress control layer 242 on the hydrogen permeation barrier layer 244. Figure 3EUnlike the fifth example shown, in which the hydrogen permeation barrier layer 244 is the outermost layer of the protective coating 240, in this example, the stress control layer 242 is the outermost layer of the protective coating 240 and is formed after the hydrogen permeation barrier layer 244. Therefore, the nanostructure 249 is embedded in the hydrogen permeation barrier layer 244.

[0098] Figure 3G is a cross-sectional view of a seventh example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3G As shown, the protective coating 240 surrounding the CNT 230 has a four-layer structure, which includes a hydrogen reduction layer 248 (including a plurality of nanostructures 249) on the CNT 230, a stress control layer 242 on the nanostructures 249 and the CNT 230, an interdiffusion layer 246 on the stress control layer 242, and a hydrogen permeation barrier layer 244 on the interdiffusion layer 246. Figure 3E Compared to the fifth example shown in FIG. 1 , in this example, the protective coating 240 includes an additional interdiffusion layer 246 formed between the stress control layer 242 and the hydrogen permeation barrier layer 244. In some embodiments, the interdiffusion layer 246 may be formed by Figure 3E The coated CNT 300 is annealed to cause metal or Si atoms to diffuse from the stress control layer 242 to the hydrogen permeation barrier layer 244 to be formed.

[0099] Figure 3H is a cross-sectional view of an eighth example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3H As shown, the protective coating 240 surrounding the CNT 230 has a four-layer structure, which includes a hydrogen reduction layer 248 (including a plurality of nanostructures 249) on the CNT 230, a hydrogen permeation barrier layer 244 on the nanostructures 249 and the CNT 230, an interdiffusion layer 246 on the hydrogen permeation barrier layer 244, and a stress control layer 242 on the interdiffusion layer 246. Figure 3G Unlike the seventh example shown, in which the hydrogen permeation barrier layer 244 is the outermost layer of the protective coating 240 , in this example, the stress control layer 242 is the outermost layer of the protective coating 240 and is formed after the hydrogen permeation barrier layer 244 .

[0100] Fig. 3I is a cross-sectional view of a ninth example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Fig. 3IAs shown, the protective coating 240 surrounding the CNT 230 has a five-layer structure, which includes a hydrogen reduction layer 248 (including a plurality of nanostructures 249) on the CNT 230, a diffusion suppression layer 250 on the nanostructures 249 and the CNT 230, a stress control layer 242 on the diffusion suppression layer 250, and a hydrogen permeation barrier layer 244 on the stress control layer 242. Figure 3E Compared to the fifth example shown, in this example, the protective coating 240 includes nanostructures 249 and an additional diffusion suppression layer 250 on the exposed surface of the CNTs 230 .

[0101] The diffusion suppression layer 250 is adapted to prevent the aggregation of the nanostructures 249. Due to the small size and high surface energy associated with the nanostructures 249, when heat accumulates on the nanostructures 249, resulting in the migration or diffusion of the nanostructures 249, the nanostructures 249 tend to aggregate to form larger aggregates. The aggregates reduce the EUV transmittance of the thin film 226. Therefore, the diffusion suppression layer 250 formed on the nanostructures 249 encapsulates the nanostructures 249 and acts as a barrier to prevent the migration or diffusion of the nanostructures 249, thereby inhibiting the aggregation of the nanostructures 249. Therefore, the reliability of the thin film 226 is improved, and the high EUV transmittance of the thin film 226 is maintained. In some embodiments, the diffusion suppression layer 250 includes a transition metal oxide or a Group 13 metal oxide. In some embodiments, the diffusion suppression layer 250 includes Y2O3, Al2O3, TiO2, HfO2, or a combination thereof.

[0102] The diffusion suppression layer 250 is relatively thin, so as not to reduce the transparency of the thin film film 226 to EUV light. In some embodiments, the thickness of the diffusion suppression layer 250 may be in the range of about 0.1 nm to about 1 nm. The diffusion suppression layer 250 may be formed by a suitable deposition technique, such as CVD, PECVD, ALD, PEALD, PVD or other suitable techniques. In some embodiments, the diffusion suppression layer 250 is formed as a conformal layer around the hydrogen reduction layer 248 and the CNT 230.

[0103] Figure 3J is a cross-sectional view of a tenth example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3J As shown, the protective coating 240 surrounding the CNT 230 has a five-layer structure, which includes a hydrogen reduction layer 248 (including a plurality of nanostructures 249) on the CNT 230, a diffusion suppression layer 250 on the nanostructures 249 and the CNT 230, a hydrogen permeation barrier layer 244 on the diffusion suppression layer 250, and a stress control layer 242 on the hydrogen permeation barrier layer 244. Fig. 3IUnlike the ninth example shown, in which the hydrogen permeation barrier layer 244 is the outermost layer of the protective coating 240 , in this example, the stress control layer 242 is the outermost layer of the protective coating 240 and is formed after the hydrogen permeation barrier layer 244 .

[0104] Figure 3K is a cross-sectional view of an eleventh example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3K As shown, the protective coating 240 surrounding the CNT 230 has a six-layer structure, which includes a hydrogen reduction layer 248 (including a plurality of nanostructures 249) on the CNT 230, a diffusion inhibition layer 250 on the nanostructures 249 and the CNT 230, a stress control layer 242 on the diffusion inhibition layer 250, an interdiffusion layer 246 on the stress control layer 242, and a hydrogen permeation barrier layer 244 on the interdiffusion layer 246. Fig. 3I Compared to the ninth example shown in FIG. 1 , in this example, the protective layer 240 includes an additional interdiffusion layer 246 located between the stress control layer 242 and the hydrogen permeation barrier layer 244. In some embodiments, the interdiffusion layer 246 may be formed by Fig. 3I The coated CNT 300 is annealed to cause metal to diffuse from the stress control layer 242 to the hydrogen permeation barrier layer 244 to form.

[0105] Figure 3L is a cross-sectional view of a twelfth example of a coated CNT 300 in a network of multiple CNTs according to some embodiments. Figure 3L As shown, the protective coating 240 surrounding the CNT 230 has a six-layer structure, which includes a hydrogen reduction layer 248 (including a plurality of nanostructures 249) on the CNT 230, a diffusion inhibition layer 250 on the nanostructures 249 and the CNT 230, a hydrogen permeation barrier layer 244 on the diffusion inhibition layer 250, an interdiffusion layer 246 on the hydrogen permeation barrier layer 244, and a stress control layer 242 on the interdiffusion layer 246. Figure 3K Unlike the eleventh example shown, in which the hydrogen permeation barrier layer 244 is the outermost layer of the protective coating 240 , in this example, the stress control layer 242 is the outermost layer of the protective coating 240 and is formed after the formation of the hydrogen permeation barrier layer 244 .

[0106] Figure 4 4 is a flow chart illustrating a method 400 for assembling a thin film for a photolithography process according to some embodiments. For example, the method 400 may be performed to assemble a thin film. Figure 1 and Figure 2A-2B The film 114 is shown. The method 400 may be performed using one or more different machines under the control of a controller or processor.

[0107] In step 402, a CNT core layer including a plurality of CNTs may be constructed on a template substrate. The plurality of CNTs may include a plurality of individual CNTs or a plurality of CNT bundles. The CNTs may be single-walled, double-walled, multi-walled CNTs, or a combination thereof. For example, the template substrate may include polyvinyl alcohol (PVA), polystyrene (PS), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), or chemical vapor deposited polyparaxylene polymers (e.g., polyparaxylene C). In some embodiments, the CNT core layer may be deposited in a plasma environment (e.g., a plasma reaction chamber (wherein the reaction gas may include, for example, C x H y , H2, Ar, O2, another suitable gas, or any combination thereof)) using a roll-to-roll process.

[0108] In step 404, a protective coating is formed to surround at least one CNT of the plurality of CNTs, thereby forming a thin film film, for example, thin film film 226 ( Figure 2A-2C ). The processing steps for forming a protective coating on CNTs will be described in detail below.

[0109] In step 406, the thin film film may be transferred to the frame, and the template substrate may be removed to make the thin film film independent. In some embodiments, a dry transfer technique is used to transfer the thin film film from the template substrate to the frame. In some embodiments, the frame is formed of silicon. Figure 2B As shown, the border may have a rectangular shape.

[0110] In step 408, the frame and the film membrane may be attached to the film frame including the vent structure. Figure 2A and Figure 2B As shown, the film frame may have the same shape as the frame (e.g., a rectangular shape). In some embodiments, the film frame may be formed of Si, SiC, SiN, glass, a low thermal expansion coefficient material (e.g., Al alloy, Ti alloy, Invar, Kovar, etc.), another suitable material, or any combination thereof. In a further example, the film frame may include a vent structure, such as Figure 2A and Figure 2B That is, the vent structure may include holes in shapes such as circles, rectangles, slits, other suitable shapes, or any combination thereof.

[0111] Figure 5 is a flow chart illustrating a method 500 of forming a protective coating 240 on a CNT 230 according to some embodiments. Figure 6A-6F is a cross-sectional view of a coated CNT at different stages of method 500 according to some embodiments. Figure 6A-6FThe method 500 of coating CNTs is discussed in detail.

[0112] In step 502, a surface treatment is performed to form hydroxyl (-OH) groups 232 on the CNT surface, such as Fig. 6A As shown. The surface treatment improves the wettability of CNT 230. Hydroxyl groups 232 also serve as reaction sites for forming nanostructures 249. In some embodiments, the surface treatment can be performed by oxidative acid treatment using various types of acids and acid mixtures (e.g., HNO3, H2SO4 / HNO3, HCl / H2SO4 / HNO3, H2O2, KMnO4, K2Cr2O7 / H2SO4, and KMnO4 / H2SO4).

[0113] In step 504, a hydrogen reduction layer 248 including a plurality of nanostructures 249 is formed on the surface of the CNT 230. Figure 6B The hydrogen reduction layer 248 may include a plurality of nanograins, nanoislands, nanocubes, or nanosheets, and may be formed by a sol-gel process, E-beam evaporation, CVD, ALD, PEALD, electrodeposition, electroless deposition, or other suitable deposition techniques. Step 504 is optional and omitted in some embodiments.

[0114] In step 506, a diffusion suppression layer 250 is deposited over the exposed surfaces of the nanostructures 249 and CNTs 230 of the hydrogen reduction layer 248, such as Figure 6C The diffusion suppression layer 250 is formed as a conformal layer and is deposited by a conformal deposition process, such as CVD, PECVD, ALD, PEALD, or PVD. Step 506 is optional and is omitted in some embodiments.

[0115] In step 508, a stress control layer 242 is deposited on the diffusion suppression layer 250, such as Fig.6D As shown, or if steps 504 and 506 are omitted, a stress control layer 242 is deposited directly over the surface of CNT 230. Stress control layer 242 is formed as a conformal layer and is deposited by a conformal deposition process, such as CVD, PECVD, ALD, PEALD, or PVD.

[0116] In step 510, a hydrogen permeation barrier layer 244 is deposited on the stress control layer 242, such as Fig. 6E The hydrogen permeation barrier layer 244 is formed as a conformal layer and is deposited by a conformal deposition process, such as CVD, PECVD, ALD, PEALD, or PVD.

[0117] In step 512, a densification process is performed to densify the various layers coated on the CNT 230. In some embodiments, the densification process is performed using Ar, N2, or NH3 plasma.

[0118] In step 514, an annealing process is performed. The annealing causes metal or silicon to diffuse from the stress control layer 242 to the hydrogen permeation barrier layer 244, thereby forming an interdiffusion layer 246 having a metal or silicon concentration gradient, such as Fig. 6F In some embodiments, the annealing is a thermal annealing performed at a temperature in the range of 200° C. to 1000° C. Step 514 is optional and omitted in some embodiments.

[0119] Figure 7 is a flow chart illustrating a method 700 of forming a protective coating 240 on a CNT 230 according to some embodiments. Figure 8A-8F is a cross-sectional view of a coated CNT at different stages of method 700 according to some embodiments. Figure 8A-8F The method 700 for coating CNTs is discussed in detail.

[0120] In step 702, a surface treatment is performed to form hydroxyl (-OH) groups 232 on the CNT surface, such as Fig. 8A As shown. The surface treatment improves the wettability of CNT 230. Hydroxyl groups 232 also serve as reaction sites for forming nanostructures 249. In some embodiments, the surface treatment can be performed by oxidative acid treatment using various types of acids and acid mixtures (e.g., HNO3, H2SO4 / HNO3, HCl / H2SO4 / HNO3, H2O2, KMnO4, K2Cr2O7 / H2SO4, and KMnO4 / H2SO4).

[0121] In step 704, a hydrogen reduction layer 248 including a plurality of nanostructures 249 is formed on the surface of the CNT 230. Figure 8B The hydrogen reduction layer 248 may include a plurality of nanograins, nanoislands, nanocubes, or nanosheets, and may be formed by a sol-gel process, E-beam evaporation, CVD, ALD, PEALD, electrodeposition, electroless deposition, or other suitable deposition techniques. Step 704 is optional and omitted in some embodiments.

[0122] In step 706, a diffusion suppression layer 250 is deposited over the exposed surfaces of the nanostructures 249 and CNTs 230 of the hydrogen reduction layer 248, such as Figure 8C The diffusion suppression layer 250 is formed as a conformal layer and is deposited by a conformal deposition process, such as CVD, PECVD, ALD, PEALD, or PVD. Step 706 is optional and is omitted in some embodiments.

[0123] In step 708, a hydrogen permeation barrier layer 244 is deposited on the diffusion suppression layer 250, such as Fig.8D As shown, or if steps 704 and 706 are omitted, a hydrogen permeation barrier layer 244 is deposited directly over the surface of CNT 230. Hydrogen permeation barrier layer 244 is formed as a conformal layer and deposited by a conformal deposition process, such as CVD, PECVD, ALD, PEALD, or PVD.

[0124] In step 710, a stress control layer 242 is deposited on the hydrogen permeation barrier layer 244, such as Fig. 8E The stress control layer 242 is formed as a conformal layer and is deposited by a conformal deposition process, such as CVD, PECVD, ALD, PEALD or PVD.

[0125] In step 712, a densification process is performed to densify the various layers coated on the CNT 230. In some embodiments, the densification process is performed using Ar, N2, or NH3 plasma.

[0126] In step 714, an annealing process is performed. The annealing causes metal or silicon to diffuse from the stress control layer 242 to the hydrogen permeation barrier layer 244, thereby forming an interdiffusion layer 246 having a metal or silicon concentration gradient, such as Fig.8F In some embodiments, the annealing is a thermal annealing performed at a temperature in the range of 200° C. to 1000° C. Step 714 is optional and omitted in some embodiments.

[0127] Fig. 9 is a flow chart illustrating a method 900 of fabricating a semiconductor device according to some embodiments. Figures 10A-10D is a cross-sectional view of a semiconductor device 1000 at different stages of a method 900 according to some embodiments. Figures 10A-10D Method 900 is discussed in detail for semiconductor devices of the present invention. At least some steps of method 900 may be performed by controlling an EUV lithography system (e.g., Figure 1 lithography system).

[0128] A semiconductor substrate or other suitable substrate is provided, which is patterned to form an integrated circuit thereon. In some embodiments, the semiconductor substrate includes silicon. Alternatively or additionally, the semiconductor substrate includes germanium, silicon germanium, or other suitable semiconductor materials, for example, III-V semiconductor materials.

[0129] exist Fig. 9 In step 902, a target layer 1020 to be patterned is formed on a semiconductor substrate 1010, such as Fig. 10AAs shown. In some embodiments, the target layer 1020 is a semiconductor substrate 1010. In some embodiments, the target layer 1020 includes: a conductive layer, such as a metal layer or a polysilicon layer; a dielectric layer, such as silicon oxide, silicon nitride, SiON, SiOC, SiOCN, SiCN, hafnium oxide, or aluminum oxide; or a semiconductor layer, such as an epitaxially formed semiconductor layer. In some embodiments, the target layer 1020 is formed on an underlying structure (e.g., an isolation structure, a transistor, or a conductive line).

[0130] exist Fig. 9 In step 904, a photoresist layer 1030 is formed on the target layer 1020, such as Fig. 10A As shown. The photoresist layer 1030 is sensitive to radiation from an exposure source during a subsequent photolithography exposure process. In some embodiments, the photoresist layer 1030 is sensitive to EUV light used in the photolithography exposure process. The photoresist layer 1030 can be formed on the target layer by spin coating or other suitable techniques. The coated photoresist layer 1030 can be further baked to drive off the solvent in the photoresist layer 1030.

[0131] exist Fig. 9 In step 906, the photoresist layer 1030 is patterned using the EUV mask 1040 having the thin film 1050 as described above, such as Fig. 10B As shown. The thin film 1050 includes the thin film film described herein. The thin film film includes at least one CNT film layer, the CNT film layer comprising a network of multiple CNTs, wherein at least one CNT of the multiple CNTs is coated with a multi-layer protective coating of the present disclosure. The patterning of the photoresist layer 1030 includes performing a photolithography exposure process by an EUV exposure system using an EUV mask 1040. During the exposure process, light emitted by an EUV light source is directed onto the EUV mask 1040. Light that passes through the thin film 1050 and is reflected by the EUV mask 1040 is then collected by a projection optical module and directed to the photoresist layer 1030. The integrated circuit (IC) design pattern defined on the EUV mask 1040 is imaged onto the photoresist layer 1030 to form a latent pattern thereon. Particles that fall during the exposure process can be captured by the thin film film so as to keep the EUV mask 1040 free of fallen particles while light is directed to the EUV mask 1040.

[0132] The patterning of the photoresist layer 1030 further includes developing the exposed photoresist layer to form a patterned photoresist layer 1030P having a plurality of openings 1035. In one embodiment where the photoresist layer 1030 is a positive photoresist layer, the exposed portion of the photoresist layer 1030 is removed during the development process. The patterning of the photoresist layer 1030 may further include other process steps, for example, various baking steps at different stages. For example, a post-exposure bake (PEB) process may be performed after the photolithography exposure process and before the development process.

[0133] exist Fig. 9 In step 908, the target layer 1020 is patterned using the patterned photoresist layer 1030P as an etching mask, such as Fig. 10C As shown. In some embodiments, patterning the target layer 1020 includes applying an etching process to the target layer 1020 using the patterned photoresist layer 1030P as an etching mask. The portion of the target layer 1020 exposed within the opening 1035 of the patterned photoresist layer 1030P is etched, while the remaining portion is protected from being etched. Currently, there is a groove 1025 in the patterned target layer 1020P.

[0134] exist Fig. 9 In step 910, the patterned photoresist layer 1030P may be removed by wet stripping or plasma ashing, such as Fig. 10D Further processing steps can then be performed.

[0135] One aspect of the present description relates to a thin film. The thin film includes a thin film film, which includes a network of multiple carbon nanotubes. At least one carbon nanotube among the multiple carbon nanotubes is surrounded by a multilayer protective coating, which includes a stress control layer and a hydrogen permeation barrier layer on the stress control layer. The stress control layer and the hydrogen permeation barrier layer each include a Me-containing nitride or a Me-containing oxynitride, and Me is selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr and combinations thereof. The Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration less than the first Me concentration. The thin film also includes: a thin film frame, attached to the thin film film along the peripheral area of ​​the thin film film; and a thin film frame, attached to the thin film frame.

[0136] Another aspect of the present description relates to a thin film-photomask structure. The thin film-photomask structure includes a thin film and a photomask. The thin film includes a thin film membrane having a network of multiple carbon nanotubes. At least one of the multiple carbon nanotubes is surrounded by a multilayer protective coating. The multilayer protective coating includes a stress control layer, a hydrogen permeation barrier layer on the stress control layer, and an interdiffusion layer between the stress control layer and the hydrogen permeation barrier layer. The stress control layer, the hydrogen permeation barrier layer, and the interdiffusion layer each include a Me-containing nitride or a Me-containing oxynitride, wherein Me is Si or a transition metal. The Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration less than the first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the interdiffusion layer has a third Me concentration less than the first Me concentration but greater than the second Me concentration.

[0137] Another aspect of the present description relates to a method for forming a semiconductor device. The method includes providing extreme ultraviolet (EUV) light to a photomask through a thin film on a photomask. The thin film includes a thin film membrane having a network of multiple carbon nanotubes. At least one of the multiple carbon nanotubes is surrounded by a multilayer protective coating, which includes a stress control layer and a hydrogen permeation barrier layer on the stress control layer. The stress control layer and the hydrogen permeation barrier layer each include a Me-containing nitride or a Me-containing oxynitride, wherein Me is selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr and a combination thereof. The Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration less than the first Me concentration. The method further includes directing a portion of the EUV light reflected from the photomask to a photoresist layer on the substrate.

[0138] The features of several embodiments are summarized above so that those skilled in the art can better understand the various aspects of the present disclosure. Those skilled in the art will appreciate that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and / or achieve the same advantages as the embodiments described herein. Those skilled in the art will also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they can make various changes, substitutions, and modifications without departing from the spirit and scope of the present disclosure.

Claims

1. A film comprising: A thin film membrane comprising a network of a plurality of carbon nanotubes, wherein at least one of the plurality of carbon nanotubes is surrounded by a multi-layer protective coating, the multi-layer protective coating comprising: a stress control layer; and a hydrogen permeation barrier layer, located on the stress control layer, wherein the stress control layer and the hydrogen permeation barrier layer each include a Me-containing nitride or a Me-containing oxynitride, Me is selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr and a combination thereof, wherein the Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration, and the second Me concentration is less than the first Me concentration; a film frame attached to the film membrane along a peripheral region of the film membrane; and A film frame is attached to the film frame.

2. The film according to claim 1, wherein The first Me concentration is in a range of about 80 atomic % to about 98 atomic %.

3. The film according to claim 1, wherein The nitrogen concentration or oxygen concentration of the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer is in the range of about 10 atomic % to about 50 atomic %.

4. The film according to claim 1, wherein The stress control layer includes SiN having a Si concentration in a range of about 80 atomic % to about 98 atomic %, and wherein the hydrogen permeation barrier layer includes SiN having a N concentration in a range of about 10 atomic % to about 50 atomic %.

5. The film according to claim 1, wherein The stress control layer includes SiON having a Si concentration in a range of about 80 atomic % to about 98 atomic %, and wherein the hydrogen permeation barrier layer includes SiON having a N concentration in a range of about 10 atomic % to about 50 atomic %.

6. The film according to claim 1, wherein The multi-layer protective coating further includes an interdiffusion layer between the stress control layer and the hydrogen permeation barrier layer.

7. The film according to claim 6, wherein The interdiffusion layer includes a Me-containing nitride or a Me-containing oxynitride, Me is selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr and a combination thereof, wherein the Me-containing nitride or the Me-containing oxynitride in the interdiffusion layer has a third Me concentration, which is less than the first Me concentration but greater than the second Me concentration.

8. The film according to claim 6, wherein The Me in the Me-containing nitride or the Me-containing oxynitride of the interdiffusion layer has a concentration gradient, wherein Me decreases gradually in a direction from the stress control layer toward the hydrogen permeation barrier layer.

9. A film-photomask structure, comprising: A thin film, comprising a thin film film, the thin film film comprising a network of a plurality of carbon nanotubes, wherein at least one carbon nanotube of the plurality of carbon nanotubes is surrounded by a multi-layer protective coating, the multi-layer protective coating comprising: Stress control layer; a hydrogen permeation barrier layer located on the stress control layer; and an interdiffusion layer, located between the stress control layer and the hydrogen permeation barrier layer, wherein the stress control layer, the hydrogen permeation barrier layer and the interdiffusion layer each include a Me-containing nitride or a Me-containing oxynitride, Me is Si or a transition metal, wherein the Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration less than the first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the interdiffusion layer has a third Me concentration less than the first Me concentration but greater than the second Me concentration; and Photomask.

10. A method of forming a semiconductor device, comprising: Extreme ultraviolet (EUV) light is provided to the photomask through a thin film on the photomask, wherein the thin film comprises a thin film film having a network of a plurality of carbon nanotubes, wherein at least one carbon nanotube of the plurality of carbon nanotubes is surrounded by a multi-layer protective coating, the multi-layer protective coating comprising: a stress control layer; and a hydrogen permeation barrier layer, located on the stress control layer, wherein the stress control layer and the hydrogen permeation barrier layer each include a Me-containing nitride or a Me-containing oxynitride, Me being selected from the group consisting of Si, Ti, Y, Hf, Zr, Zn, Mo, Cr and a combination thereof, wherein the Me-containing nitride or the Me-containing oxynitride in the stress control layer has a first Me concentration, and the Me-containing nitride or the Me-containing oxynitride in the hydrogen permeation barrier layer has a second Me concentration less than the first Me concentration; and A portion of the EUV light reflected from the photomask is directed onto a photoresist layer on a substrate.

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