Extreme ultraviolet masks and methods of use and formation thereof

Abstract

An extreme ultraviolet mask is provided that includes a substrate to which a thin film frame is attached, a reflective multilayer stack on the substrate, and a patterned absorber layer on the reflective multilayer stack. In some embodiments, the thin film frame is attached to the substrate using an adhesive between the thin film frame and the substrate. In some embodiments, the thin film frame is located in trenches formed in the reflective multilayer stack and the patterned absorber layer. In other embodiments, the thin film frame is not located in trenches formed in the reflective multilayer stack and the patterned absorber layer. Embodiments of the present disclosure also relate to methods of using and forming an extreme ultraviolet mask.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to extreme ultraviolet masks and methods of using and forming the same. Background Art

[0002] The semiconductor industry has experienced exponential growth. Technological advances in materials and design have produced generations of integrated circuits (ICs), each with smaller and more complex circuits than the previous generation. During IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased, while geometry size (i.e., the smallest component or line that can be created using a manufacturing process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and reducing associated costs. Summary of the invention

[0003] An embodiment of the present disclosure provides an extreme ultraviolet (EUV) mask, comprising: a substrate; a reflective multilayer stack located above the substrate; a patterned absorption layer located above the reflective multilayer stack; and a film frame located on the substrate.

[0004] Another embodiment of the present disclosure provides a method for using an extreme ultraviolet mask, the method comprising: exposing the extreme ultraviolet mask to incident radiation, the extreme ultraviolet mask comprising: a substrate; a reflective multilayer stack located above the substrate; a patterned absorption layer located above the reflective multilayer stack; a groove located in the reflective multilayer stack and the patterned absorption layer; a thin film frame bonding layer located on the substrate and at the bottom of the groove; and a thin film frame located on the thin film frame bonding layer; absorbing a portion of the incident radiation in the patterned absorption layer; and blocking a portion of the incident radiation from reaching the thin film frame bonding layer at the bottom of the groove by one or more of the patterned absorption layer or the reflective multilayer stack.

[0005] Another embodiment of the present disclosure provides a method for forming an extreme ultraviolet (EUV) mask, comprising: forming a reflective multilayer stack on a substrate; depositing a covering layer on the reflective multilayer stack; forming a buffer layer on the covering layer; depositing an absorption material layer on the buffer layer; forming a hard mask layer on the absorption material layer; etching the hard mask layer to form a patterned hard mask layer; using the patterned hard mask layer as an etching mask, etching the absorption material layer to form multiple openings therein; removing the patterned hard mask layer; forming grooves in the absorption material layer, the buffer layer, the covering layer and the reflective multilayer stack; and attaching a thin film frame to the substrate in the grooves. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Aspects of the present disclosure are best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, the various components are not drawn to scale. In fact, the dimensions of the various components may be arbitrarily increased or reduced for clarity of discussion.

[0007] Figures 1A to 1J is a cross-sectional view of an extreme ultraviolet (EUV) mask according to various embodiments of the present disclosure.

[0008] Figure 2A and Figure 2B A film frame for manufacturing an EUV mask and attaching a film carrying a film to a substrate to provide a Figure 1A Flowchart of the EUV mask method.

[0009] FIG. 3A to FIG. 3M According to some embodiments Figure 2A and Figure 2B Cross-sectional views of an EUV mask at various stages of the manufacturing process.

[0010] Figure 4 is a cross-sectional view of an extreme ultraviolet (EUV) mask according to a second embodiment.

[0011] Figure 5 is a flow chart of a method of using an EUV mask according to some embodiments.

[0012] Figure 6 Included are schematic cross-sectional views of a pellicle attached to a pellicle frame and a pellicle frame attached to a mask substrate according to some embodiments. DETAILED DESCRIPTION

[0013] 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 the present disclosure. Of course, these are merely examples and are not intended to be limiting. For example, in the following description, forming a first component above or on a second component may include an embodiment in which the first component and the second component are directly contacted, and may also include an embodiment in which an additional component may be formed between the first component and the second component so that the first component and the second component 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 embodiments and / or configurations discussed.

[0014] Additionally, for ease of description, spatially relative terms such as "below," "beneath," "lower," "above," "upper," etc. may be used herein to describe the relationship of one element or component to another element or component 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 should likewise be interpreted accordingly.

[0015] In the manufacture of integrated circuits (ICs), a series of reusable photomasks (also referred to herein as photolithography masks or masks) are used to create patterns representing different layers of the IC in order to transfer the design of each layer of the IC to a semiconductor substrate during the semiconductor device manufacturing process.

[0016] As IC size shrinks, extreme ultraviolet (EUV) light with a wavelength of 13.5 nm is used, for example, in the lithography process to transfer very small patterns (e.g., nanoscale patterns) from a mask to a semiconductor wafer. Because most materials are highly absorptive at a wavelength of 13.5 nm, EUV lithography utilizes a reflective EUV mask having a reflective multilayer to reflect incident EUV light, and an absorption layer on top of the reflective multilayer to absorb radiation in areas where the mask should not reflect light. The reflective multilayer and the absorption layer are located on a low thermal expansion material substrate. The reflective multilayer reflects incident EUV light, and the patterned absorption layer on top of the reflective multilayer absorbs light in areas where the mask should not reflect light. The mask pattern is defined by the absorption layer and is transferred to the semiconductor wafer by partial reflection of EUV light from the reflective surface of the EUV mask.

[0017] In EUV lithography, in order to separate the reflected light from the incident light, the EUV mask is illuminated with oblique incident light tilted at an angle of 6 degrees to the normal. The obliquely incident EUV light is reflected by the reflective multilayer or absorbed by the absorption layer. In the manufacture of EUV masks, in that case, if the absorption layer is thick, shadows may be formed during EUV lithography. For example, the reflected light can be partially scattered by the absorption layer. The mask shadow effect, also known as the mask 3D effect, may cause undesirable feature size-dependent focus and pattern placement shifts. With the advancement of technology nodes, the mask 3D effect becomes worse. As the pattern size decreases, the mask 3D effect becomes stronger, such as horizontal / vertical shadows.

[0018] The desire for more densely packed integrated devices has led to changes in photolithography processes to create smaller individual feature sizes. The minimum feature size or "critical dimension" (CD) achievable by the process is roughly given by the formula CD = k 1 *λ / NA is determined by k 1is a process specific coefficient, λ is the wavelength of the applied light / energy, and NA is the numerical aperture of the optical lens as seen from the substrate or wafer.

[0019] For a given k 1 In the manufacture of densely packed features of high value, the ability to project a usable image of a small feature onto the wafer is limited by the wavelength λ and the ability of the projection optics to capture sufficient diffraction orders from the illuminated mask. When densely packed features or isolated features are made from a photomask or intermediate mask of a specific size and / or shape, the transition between light and dark at the edges of the projected image may not be clearly defined enough to properly form the target photoresist pattern. This may result in, among other things, reduced contrast in the aerial image and reduced quality of the resulting photoresist profile. Therefore, features of 150nm or less in size may require the use of a phase shift mask (PSM) or techniques to enhance the image quality at the wafer, for example, sharpening the edges of the features to improve the photoresist profile.

[0020] Phase shifting generally involves selectively changing the phase of a portion of the energy passing through the photomask / reticle so that the phase shifted energy is added or subtracted from the energy without phase shift at the surface of the material on the wafer to be exposed and patterned. By carefully controlling the shape, position and phase shift angle of the mask features, the resulting photoresist pattern can have more precisely defined edges. As feature size decreases, the imbalance of transmitted intensity between the 0° and 180° phase portions and the phase shift that varies from 180° can cause critical dimension (CD) variations and placement errors in the photoresist pattern.

[0021] Phase shifting can be achieved in a variety of ways. For example, a process called attenuated phase shifting (AttPSM) utilizes a mask that includes a layer of non-opaque material, which causes a phase shift in the light passing through the non-opaque material compared to the light passing through the transparent portion of the mask. In addition, the non-opaque material can adjust the amount (intensity / amplitude) of light transmitted through the non-opaque material compared to the amount of light transmitted through the transparent portion of the mask.

[0022] Another technique is called alternating phase shift, in which a transparent mask material (e.g., quartz or SiO 2The dimensions of a transparent mask substrate (e.g., a substrate) are set (e.g., etched) to have areas of different depths or thicknesses. The depth is selected to produce a desired relative phase difference in light passing through areas of different depths / thicknesses. The resulting mask is called an "alternating phase-shift mask" or "alternating phase-shift mask" (AltPSM). AttPSM and AltPSM are referred to as "APSM" in this article. The portion of the AltPSM with a thicker depth is called the 0° phase portion, while the portion of the AltPSM with a smaller depth is called the 180° phase portion. The depth difference allows light to propagate half the wavelength in the transparent material, generating a 180° phase difference between the 0° and 180° portions. In some embodiments, the patterned phase-shift material is located on a portion of the transparent mask substrate that is not etched to different depths. The phase-shift material is a material that affects the phase of light passing through the phase-shift material, so that the phase of light passing through the phase-shift material is offset relative to the phase of light that does not pass through the phase-shift material (e.g., only passes through the transparent mask substrate material but not through the phase-shift material). The phase shift material may also reduce the amount of light transmitted through the phase shift material relative to the amount of incident light that passes through portions of the mask not covered by the phase shift material.

[0023] In embodiments of the present disclosure, a film frame is attached to a substrate of a photolithography mask with or without an adhesive. Unlike other masks used in a lithography process in which a film frame is attached to an absorber layer of a photolithography mask, embodiments of the present disclosure have a film frame of thermally conductive resistive material that is directly attached to or formed on a substrate. In some embodiments of the present disclosure, the film frame is located in a groove formed in a reflective multilayer stack, a cover layer, and an absorber layer of the mask, and is directly attached to the substrate at the bottom of such a groove. Positioning the film frame in the groove and attaching the film frame to the substrate at the bottom of the groove helps to reduce the harmful effects of exposure of the adhesive to incident radiation used during a lithography process using a photolithography mask. Exposure of the adhesive to incident radiation can degrade the adhesive in a manner that negatively affects the service life of the film frame.

[0024] Figure 1A is a cross-sectional view of an EUV mask 100 according to a first embodiment of the present disclosure. The embodiments of the present disclosure are not limited to EUV masks. For example, the embodiments of the present disclosure are applicable to photomasks used in processes that do not utilize EUV radiation. Figure 1A , EUV mask 100 includes substrate 102, reflective multilayer stack 110 located above the front surface of substrate 102, optional capping layer 120 located above reflective multilayer stack 110, and patterned absorption layer 140P located above optional capping layer 120. In some embodiments, an optional patterned buffer layer (not shown) may be provided between capping layer 120 and patterned absorption layer 140P. EUV mask 100 also includes a conductive layer 104 located above the back surface of substrate 102 opposite to the front surface.

[0025] The patterned absorption layer 140P and the patterned buffer layer (when present) include a pattern of openings 152 corresponding to the circuit pattern to be formed on the semiconductor wafer. The pattern of the openings 152 is located in the pattern area 100A of the EUV mask 100, exposing the surface of the cover layer 120. The pattern area 100A is surrounded by the peripheral area 100B of the EUV mask 100. The peripheral area 100B corresponds to a non-patterned area of ​​the EUV mask 100, which is not used in the exposure process during IC manufacturing. In some embodiments, the pattern area 100A of the EUV mask 100 is located at the central area of ​​the substrate 102, and the peripheral area 100B is located at the edge portion of the substrate 102. The pattern area 100A is separated from the peripheral area 100B by a groove 154. The groove 154 extends through the patterned absorption layer 140P, the cover layer 120 and the reflective multilayer stack 110, exposing the front surface of the substrate 102.

[0026] According to some embodiments of the present disclosure, the patterned absorption layer 140P is a layer of absorption material, such as tantalum boron nitride, hafnium oxide, silicon nitride or tantalum nitride. In some embodiments, the absorption material is an alloy of a transition metal (e.g., ruthenium (Ru), chromium (Cr), platinum (Pt), gold (Au), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), tungsten (W) or palladium (Pb)) and at least one alloy element selected from ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt), palladium (Pd), tungsten (W), gold (Au), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), hafnium (Hf), boron (B), nitrogen (N), silicon (Si), zirconium (Zr) or vanadium (V). According to the embodiments of the present disclosure, it is not limited to the use of the above absorption materials. For example, in other embodiments of the present disclosure, different absorption materials can be used.

[0027] According to some embodiments of the present disclosure, the patterned absorption layer 140P includes a first layer of absorption material and a second layer of absorption material different from the first layer of absorption material, wherein the refractive index of the first layer of absorption material is less than 0.95 and the extinction coefficient (k) is greater than 0.01. The extinction coefficient k is a function of the attenuation of the amplitude of the light wave propagating in the absorption material. Examples of absorbing materials having a refractive index less than 0.95 and an extinction coefficient greater than 0.01 include alloys of ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt), gold (Au), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), tungsten (W) or palladium (Pd) and at least one alloying element selected from ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt), palladium (Pd), tungsten (W), gold (Au), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), hafnium (Hf), boron (B), nitrogen (N), silicon (Si), zirconium (Zr) or vanadium (V).

[0028] According to an embodiment of the present disclosure, the reflective multilayer stack 110 includes alternating material layers for EUV embodiments, providing efficient reflection of EUV radiation. Examples of suitable materials include molybdenum and silicon. Embodiments of the present disclosure are not limited to reflective multilayer stacks using molybdenum and silicon. For example, embodiments of the present disclosure are applicable to reflective multilayer stacks of materials other than molybdenum and silicon.

[0029] According to an embodiment of the present disclosure, capping layer 120 includes a material that effectively retards oxidation of the material of multilayer stack 110 and provides suitable loss of EUV radiation reflected by multilayer stack 110. Examples of such materials include TaO, TaBO, ruthenium-containing compounds, or combinations thereof.

[0030] According to an embodiment of the present disclosure, the substrate 102 includes a material such as Si, silicon dioxide, titanium, or a combination thereof. An example of a material for the substrate 102 includes a low thermal expansion material substrate such as TiO 2 Doped SiO 2 .

[0031] Figure 1A Also shown is a cross-sectional view of a membrane 114 including a membrane 232 supported on a membrane frame 209 according to some embodiments of the present disclosure. Figure 1A As shown, the photomask 100 may include a mask substrate 102 and a patterned absorption layer 140P located above the mask substrate 102 .

[0032] In some examples, the mask substrate 102 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 patterned absorption layer 140P can be located above the mask substrate 102 as discussed above, and can be designed according to the integrated circuit components formed above the semiconductor substrate during the photolithography process. The patterned absorption layer 140P can be formed by depositing a material layer and patterning the material layer to have one or more openings 152 and one or more absorption regions, wherein the radiation beam can pass through the one or more openings 152 without being absorbed, and the one or more absorption regions can completely or partially block the radiation beam.

[0033] In addition to the above materials for the absorption layer 140P, the absorption layer 140P may include metals, metal alloys, metal silicides, metal nitrides, metal oxides, metal oxynitrides, or other applicable materials. Examples of materials that may be used to form the absorption layer 140P may 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 O y N z 、 x B y O z 、 x B y N z 、Ag x O y 、Ag xN y ,Ni,Ni x O y 、Ni x O y N z Etc. The compound x / y / z ratio is not limited.

[0034] In some embodiments, photomask 100 is an EUV mask. However, in other embodiments, photomask 100 may be a photomask for a lithography process that utilizes radiation other than EUV, such as a lithography process that utilizes UV radiation.

[0035] like Figure 1A As shown, the membrane 114 may be positioned over the patterned absorber layer 140P, thereby forming an enclosed interior volume 207 enclosed by the membrane 114 , the patterned absorber layer 140P, and the substrate 102 .

[0036] In the illustrated embodiment, the membrane 232 is supported by a membrane frame 209, which may be located above at least one of the substrate 102, the patterned absorber layer 140P, the reflective multilayer stack 110, and the capping layer 120. The membrane frame 209 may be designed in a variety of sizes, shapes, and configurations. In some embodiments, the membrane frame 209 may have a circular, rectangular, or any other suitable shape. In some embodiments, the membrane frame 209 may be made of Ti, Si, SiC, SiN, titanium oxide, glass, a low thermal expansion coefficient material such as an Al alloy, a Ti alloy, such as Nickel iron, such as ), another suitable material, or a combination thereof. In some embodiments, suitable processes for forming the film frame 209 may include a machining process, a sintering process, a photochemical etching process, other applicable processes, or a combination thereof. In the illustrated embodiment, the film frame 209 is located within the groove 154. As described in more detail below, a first end of the film frame 209 is directly attached to the substrate 102 of the photomask 100. In some embodiments, the first end of the film frame directly attached to the substrate 102 is located below the cover layer 120 and below the absorption layer 140.

[0037] like Figure 1AAs further shown, the film frame 209 may also include a vent structure 211 extending through the film frame 209. In some embodiments, the vent structure 211 may include one or more holes formed through the film frame 209. The holes may take any shape, including circular holes, rectangular holes, slit-shaped holes, other shapes, or any combination thereof. The holes may allow air or other gases to flow through portions of the film frame 209. The vent structure 211 is used to balance the air pressure between the open space defined by the film frame 209, the film assembly 230, and the substrate 102 and the environment outside the film frame 209, the film assembly 230, and the substrate 102. In some embodiments, the holes may include a filter to minimize the passage of foreign particles through the vent structure 211. In some embodiments, the vent structure 211 may prevent the film 232 from rupturing due to increased pressure within the internal volume 207 during the EUV lithography process.

[0038] like Figure 1A As further shown, according to an embodiment of the present disclosure, the film frame 209 includes two ends, an upper end 215 and a lower end 217. The lower end of the film frame 209 is attached to the substrate 102, for example, directly attached to the substrate 102 via a film frame adhesive 213. The upper end 215 of the film frame 209 is attached to the film 114, for example, using a film adhesive 239. Figure 1A In an embodiment of the present invention, the lower end 217 is located at a level below the cover layer 120 and below the absorber layer 140. In some embodiments, the film frame adhesive 213 and the film adhesive 239 are formed of an adhesive that is susceptible to degradation due to exposure to EUV radiation or excessive temperature. For example, these adhesives can be formed of a cross-linking adhesive, a thermoplastic elastomer adhesive, a polystyrene adhesive, an acrylic adhesive, a silicon-based adhesive, an epoxy adhesive, or a combination thereof. Specific examples of materials used as the film frame adhesive 213 and / or the film adhesive 239 include acrylic adhesives, silicon, and a styrene-ethylene-butadiene-styrene rubber (SEBS) combination thereof.

[0039] In some embodiments, the upper and lower ends of the film frame 209 may be subjected to surface treatment to enhance adhesion of the film frame 209 to the film frame adhesive 213 and the film adhesive 239. In some examples, the surface treatment may include oxygen plasma treatment, another applicable treatment, or a combination thereof. However, in other examples, the film frame 209 may not be subjected to surface treatment.

[0040] like Figure 1AAs further shown, the pellicle 114 includes a pellicle assembly 230, which includes a pellicle 232 and a film border 234 located around the periphery of the pellicle 232 and above the pellicle frame 209. The pellicle 232 extends over the pattern area of ​​the patterned absorption layer 140P to protect the pattern area from contaminant particles. Particles that are inadvertently deposited on the pattern area of ​​the photomask 100 may cause defects and lead to degradation of the transferred pattern. Particles may be introduced in any of a variety of ways, such as during a cleaning process and / or during processing of the photomask 100. By keeping the contaminant particles away from the focal plane of the photomask 100, a high-fidelity pattern transfer from the photomask 100 to the semiconductor wafer may be achieved.

[0041] like Figure 1A As shown, the film adhesive 239 can be located between the film boundary 234 and the upper end 215 of the film frame 209, attaching the film 232 to the upper end 215 of the film frame 209. In some embodiments, the film adhesive 239 can be formed of a thermoplastic elastomer type adhesive, a polystyrene type adhesive, an acrylic type adhesive, a silicon-based adhesive, an epoxy type adhesive, another suitable adhesive, or a combination thereof. In some embodiments, the film adhesive 239 can be formed of a material different from the material constituting the film frame adhesive 213.

[0042] The film border 234 can be attached around the periphery of the pellicle 232 and thereby mechanically support the pellicle 232. When the photomask structure 100 is fully assembled, the film border 234 can in turn be mechanically supported by the upper end 215 of the pellicle frame 209. That is, the pellicle frame 209 can mechanically support the film border 234 and the pellicle 232 on the substrate 102 of the photomask 100.

[0043] In some embodiments, the membrane boundary 234 and / or the thin film 232 may be formed of Si. In further examples, the membrane boundary 234 may be formed of boron carbide, graphene, carbon nanotubes, SiC, SiN, SiO 2 , SiON, MoSi, 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, other suitable materials, allotropes of any of these materials, or combinations thereof.

[0044] Figure 1B Shows Figure 1A An alternative embodiment of the embodiment of Figure 1B In the embodiment of , there is no peripheral area 100B. Figure 1B In, with Figure 1A Identical parts to the parts shown are identified by the same reference numerals.

[0045] Figure 1C Shows Figure 1A Top view of EUV mask 100 in FIG. Figure 1D It is along the line DD Figure 1C 154 is an enlarged side view of a portion of an EUV mask 100. According to an embodiment of the present disclosure, the EUV mask 100 includes a film frame 209, which includes a lower end 217 fixed to the substrate 102 by a film frame adhesive 213. The film frame adhesive 213 directly contacts the upper surface of the substrate 102 and directly contacts the lower end 217 of the film frame 209. In the illustrated embodiment, the film frame adhesive 213 is located at the bottom of the groove 154. In other embodiments, one or more other material layers may be present on the upper surface of the substrate. In such an embodiment, the upper surface of such other material layer defines the bottom of the groove 154. In such an embodiment, the film frame adhesive 213 directly contacts the upper surface of the uppermost layer of the other material layers on the substrate 102. Figure 1D In the example, the upper surface of the film frame 209 ( Figure 1A 215) is attached to the film border 234 by a film adhesive 239. Figure 1D As shown, the film frame adhesive 213 is located below the upper surface of the reflective multilayer stack 110 and below the upper surface of the patterned absorber layer 140P. In contrast, in some embodiments, the film adhesive 239 and the upper end 215 of the film frame 209 are located above the upper surface of the patterned absorber layer 140P. Figure 1D , EUV radiation impinging on the upper surface of patterned absorber layer 140P is represented by ray 155, which has an incident angle α relative to the upper surface of patterned absorber layer 140P. In some embodiments, α is equal to about 6°; however, embodiments according to the present disclosure include incident angles less than or greater than 6°.

[0046] The adhesive used to secure the film frame 209 to the substrate 102 (i.e., the film frame adhesive 213) can degrade due to direct exposure to EUV radiation, reflected EUV radiation, and / or excessive thermal energy. For example, when the film frame adhesive 213 is exposed to excessive EUV radiation or thermal energy, the adhesive properties of the film frame adhesive 213 can degrade, such as weakening or failing. EUV radiation directly impinging on the film frame adhesive 213 can cause degradation of the film frame adhesive 213. Reflected EUV radiation impinging on the film frame adhesive 213 can also cause degradation of the film frame adhesive 213. EUV radiation impinging on the film frame adhesive 213 or on portions of material adjacent to the film frame adhesive 213 can cause the temperature of the film frame adhesive 213 or the portions of material adjacent to the film frame adhesive 213 impinged by the EUV radiation to increase, sometimes to a level that causes degradation of the film frame adhesive 213. When the temperature of the material adjacent to the film frame adhesive 213 increases and the heat energy is conducted to the film frame adhesive 213, the temperature of the film frame adhesive 213 may increase to a level that causes the film frame adhesive 213 to deteriorate. For example, some EUV masks use an adhesive to attach the film frame to the upper surface of the absorbent material layer. When the film frame is attached to the upper surface of the absorbent material layer using an adhesive, the service life of the EUV mask may be shortened due to exposure to EUV radiation or heat energy generated by EUV radiation. Unexpected shortening of the service life of the EUV mask adversely affects the yield of the photolithography process. The EUV mask formed according to some embodiments of the present disclosure includes a film frame adhesive 213 located at the bottom of the groove 154, wherein the film frame adhesive 213 is less exposed to EUV radiation and heat energy generated by EUV radiation that impinges on a portion of the EUV mask compared to an EUV mask in which the lower end of the film frame is attached to the upper surface of the absorbent layer. In other embodiments described in more detail below, the outermost peripheral area 100B is omitted.

[0047] Figure 1E The various size identifiers F, X, Y, D, d, W1 and W2 are added Figure 1D F represents the width of the film frame 209. X represents the width of the groove 154. Y represents the width of the film frame adhesive 213. D represents the distance between the bottom of the groove 154 and the lower side of the film 232. d represents the distance between the upper surface of the substrate 102 and the bottom of the groove 154 (for example, the lower surface of the substrate 102). W1 represents the distance between the outer edge of the pattern area 100A and the inner side of the film frame 209. W2 represents the distance between the inner edge of the peripheral area 100B and the opposite outer side of the film frame 209. Figure 1E In the embodiment, W1 and W2 are not equal. Figure 1F yes Figure 1EEmbodiment, wherein W1 and W2 are equal. Figure 1E The description of the components also applies to Figure 1E Shared Figure 1F To improve Figure 1F Clarity, Figure 1F No reference numbers are added.

[0048] according to Figure 1E and Figure 1F In some embodiments, F may vary, but in some embodiments, F is between 1 mm and 6 mm. In other embodiments. F is between 2 mm and 5 mm. F is not limited to the values ​​in the above range. For example, F may be less than 1 mm or greater than 6 mm. X is equal to or greater than the sum of Y+W1+W2. The value of X may vary, but in some embodiments, X is between 1 mm and 25 mm. In other embodiments. X is between 2 mm and 20 mm. X is not limited to the values ​​in the above range. For example, X may be less than 1 mm or greater than 25 mm. Y may be equal to or less than F. For example, Y is between 1 mm and 6 mm. In other embodiments, Y is between 2 mm and 5 mm. Y is not limited to the values ​​in the above range. For example, Y may be less than 1 mm. D may vary and is generally equal to a value determined using a scanner of an EUV mask. In some embodiments, D is greater than d. d is equal to or greater than the sum of the depth of the absorber layer 140P + the depth of the capping layer 120 + the depth of the multilayer stack 110 and any other layers on or between these layers. In some embodiments, the ratio of d:D is between 7000:1 and 3000:1. Figure 1F The height h of the combination of the film frame adhesive 213 and the film frame 209 is identified. The height h is greater than d and less than D. When the height h is greater than d and less than D, the upper surface of the film frame 209 is located above the upper surface of the absorbent layer 140P and below the film 232. The values ​​of W1 and W2 are a function of the tolerance of the tool used to mount the film frame 209 in the groove 154, the tolerance of the process used to form the groove 154, and the need for any undercutting of the edges of the pattern area 100A or the peripheral area 100B. In some embodiments, W1 and W2 are greater than 1 micron. In some embodiments, the ratio of X to W1 or W2 is between 21000:1 and 2000:1. According to some embodiments of the present disclosure, W1 and / or W2 may be selected to be sufficiently small so that, based on the angle of incidence of EUV radiation 155 and the value of d, the amount of EUV radiation that impinges on the bottom surface of trench 154 is minimized, and / or the amount of EUV radiation that impinges on film frame adhesive 213 or materials near film frame adhesive 213 is minimized. Examples of materials near film frame adhesive 213 include portions of substrate 102 adjacent to film frame adhesive and portions of film frame 209 adjacent to film frame adhesive 213.

[0049] Figure 1G An embodiment of the present disclosure is shown in which the outer edge of the pattern area 100A has been etched to provide an undercut surface 166, resulting in the outer edge of the pattern area being non-vertical. The undercut surface 166 includes an upper end and a lower end, the upper end having a distance W1 from the inner side of the film frame 209, and the lower end having a distance W1' from the same inner side of the film frame 209. Figure 1G An embodiment of the present disclosure is also shown in which the inner edge of the peripheral region 100B has been etched to provide an etched footing surface 168, resulting in the inner edge of the peripheral region 100B being non-vertical. The etched footing surface 168 includes an upper end and a lower end, the upper end being a distance W2 from the outer side of the film frame 209, and the lower end being a distance W2' from the same outer side of the film frame 209. Figure 1G In the embodiment shown in FIG. 1 , the groove 154 includes dimensions X and X'. In some embodiments, X=X', while in other embodiments, X is not equal to X'. Figure 1G Alternatives to the illustrated embodiment include edges of the pattern region 100A and edges of the peripheral region 100B both including undercut surfaces. Figure 1H This alternative is shown in . In another embodiment, the edge of the pattern area 100A and the edge of the peripheral area 100B are etched to provide an etched footing surface. Fig. 1I This alternative is shown in .

[0050] exist Figure 1J , wherein the alternative embodiment shown shows an additional material layer 156, such as silicon or silicon dioxide, on the substrate 102. This additional material layer 156 can be a residue of a processing step performed before attaching the film frame 209 to the substrate 102, or it can also be provided by a specific formation step. The additional layer 156 can provide a further barrier to thermal energy conducted to the film frame adhesive 213.

[0051] Figure 2A and Figure 2B is a flow chart of a method 200 for fabricating an EUV mask (eg, EUV mask 100 ) having embodiments of the present disclosure. FIG. 3A to FIG. 3L 2 is a cross-sectional view of an EUV mask 100 at various stages of a manufacturing process according to some embodiments. The method 200 is discussed in detail below with reference to the EUV mask 100. In some embodiments, additional operations are performed before, during, and / or after the method 200, or some of the operations described are replaced and / or eliminated. In some embodiments, some of the components described below are replaced or eliminated. One of ordinary skill in the art will appreciate that while some embodiments are discussed with operations performed in a particular order, the operations may be performed in another logical order.

[0052] refer to Figure 2A and Figure 3AAccording to some embodiments, method 200 includes operation 202 , in which a reflective multilayer stack 110 is formed over a substrate 102 . Figure 3A is a cross-sectional view of an initial structure of the EUV mask 100 after forming a reflective multilayer stack 110 over the substrate 102 , according to some embodiments.

[0053] refer to Figure 3A The initial structure of the EUV mask 100 includes a substrate 102 made of glass, silicon, quartz, or other low thermal expansion materials. The low thermal expansion material helps to minimize image distortion caused by mask heating during use of the EUV mask 100. In some embodiments, the substrate 102 includes fused silica, fused quartz, calcium fluoride, silicon carbide, black diamond, or titanium oxide doped silicon oxide (SiO 2 / TiO 2 ). In some embodiments, the substrate 102 has a thickness in the range of about 1 mm to about 7 mm. In some cases, if the thickness of the substrate 102 is too small, the risk of the EUV mask 100 breaking or warping increases. On the other hand, in some cases, if the thickness of the substrate is too large, the weight of the EUV mask 100 may increase unnecessarily.

[0054] In some embodiments, the conductive layer 104 is disposed on the rear surface of the substrate 102. In some embodiments, the conductive layer 104 is in direct contact with the rear surface of the substrate 102. The conductive layer 104 is adapted to provide electrostatic coupling of the EUV mask 100 to an electrostatic mask chuck (not shown) during manufacture and use of the EUV mask 100. In some embodiments, the conductive layer 104 comprises chromium nitride (CrN) or tantalum boride (TaB). In some embodiments, the conductive layer 104 is formed by a deposition process such as, for example, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), or physical vapor deposition (PVD). The thickness of the conductive layer 104 is controlled so that the conductive layer 104 is optically transparent.

[0055] The reflective multilayer stack 110 is disposed above the front surface of the substrate 102 opposite the rear surface. In some embodiments, the reflective multilayer stack 110 is in direct contact with the front surface of the substrate 102. The reflective multilayer stack 110 provides high reflectivity for EUV light. In some embodiments, the reflective multilayer stack 110 is configured to achieve a reflectivity of about 60% to about 75% at a peak EUV illumination wavelength (e.g., EUV illumination of 13.5 nm). Specifically, when EUV light is applied to the surface of the reflective multilayer stack 110 at an incident angle of 6°, the maximum reflectivity of light near a wavelength of 13.5 nm is about 60%, about 62%, about 65%, about 68%, about 70%, about 72%, or about 75%.

[0056] In some embodiments, the reflective multilayer stack 110 includes alternating stacked layers of high refractive index materials and low refractive index materials. On the one hand, materials with high refractive index tend to scatter EUV light, and on the other hand, materials with low refractive index tend to transmit EUV light. Pairing these two materials together provides resonant reflectivity. In some embodiments, the reflective multilayer stack 110 includes alternating stacked layers of molybdenum (Mo) and silicon (Si). In some embodiments, the reflective multilayer stack 110 includes alternating stacked Mo and Si layers, wherein Si is located at the top layer. In some embodiments, the molybdenum layer is in direct contact with the front surface of the substrate 102. In some other embodiments, the silicon layer is in direct contact with the front surface of the substrate 102. Optionally, the reflective multilayer stack 110 includes alternating stacked Mo and beryllium (Be) layers.

[0057] The thickness of each layer in the reflective multilayer stack 110 depends on the EUV wavelength and the incident angle of the EUV light. The thickness of the alternating layers in the reflective multilayer stack 110 is adjusted to maximize the constructive interference of EUV light reflected at each interface and minimize the overall absorption of EUV light. In some embodiments, the reflective multilayer stack 110 includes 30 to 60 pairs of alternating layers of Mo and Si. Each pair of Mo / Si has a thickness in the range of about 2 nm to about 7 nm, with a total thickness in the range of about 100 nm to about 300 nm.

[0058] In some embodiments, each layer in the reflective multilayer stack 110 is deposited over the substrate 102 and the underlying layers using ion beam deposition (IBD) or DC magnetron sputtering. The deposition method used helps ensure that the thickness uniformity of the reflective multilayer stack 110 is better than about 0.85 on the substrate 102. For example, to form the Mo / Si reflective multilayer stack 110, a Mo target is used as a sputtering target, and argon (Ar) (gas pressure of 1.3×10 -2 Pa to 2.7×10 -2 Pa) as the sputtering gas, with an ion acceleration voltage of 300 V to 1500 V and a deposition rate of 0.03 to 0.30 nm / sec, and then a Si target was used as the sputtering target and Ar gas (pressure of 1.3x10 -2 Pa to 2.7×10 -2 Pa was used as a sputtering gas, and the Si layer was deposited at a deposition rate of 0.03 to 0.30 nm / sec at an ion acceleration voltage of 300 to 1500 V. A Mo / Si reflective multilayer stack was deposited by stacking Si and Mo layers for 40 to 50 cycles, each cycle including the above steps.

[0059] refer to Figure 2A and Figure 3BAccording to some embodiments, the method 200 proceeds to operation 204 where a capping layer 120 is deposited over the reflective multilayer stack 110 . Figure 3B After depositing a capping layer 120 over the reflective multilayer stack 110 according to some embodiments Figure 3A A cross-sectional view of the structure.

[0060] refer to Figure 3B , a capping layer 120 is disposed over the topmost surface of the reflective multilayer stack 110. The capping layer 120 helps protect the reflective multilayer stack 110 from oxidation and any chemical etchants to which the reflective multilayer stack 110 may be exposed during subsequent mask fabrication processes.

[0061] In some embodiments, the capping layer 120 includes a material that is resistant to oxidation and corrosion and has low chemical reactivity with common atmospheric gas species such as oxygen, nitrogen, and water vapor. In some embodiments, the capping layer 120 includes a transition metal such as, for example, ruthenium (Ru), iridium (Ir), rhodium (Rh), platinum (Pt), palladium (Pd), osmium (Os), rhenium (Re), vanadium (V), tantalum (Ta), hafnium (Hf), tungsten (W), molybdenum (Mo), zirconium (Zr), manganese (Mn), technetium (Tc), or alloys thereof.

[0062] In some embodiments, the capping layer 120 is formed using a deposition process such as, for example, IBD, chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD). In the case where a Ru layer is formed as the capping layer 120 using IBD, the deposition can be performed in an Ar atmosphere by using a Ru target as a sputtering target.

[0063] refer to Figure 2A and Figure 3C According to some embodiments, method 200 proceeds to optional operation 206 where an optional buffer layer 130 is deposited over capping layer 120 . Figure 3C According to some embodiments, after the buffer layer 130 is deposited on the cap layer 120 Figure 3B In other embodiments where optional operation 206 is omitted, the optional buffer layer 130 is not present. The following description describes embodiments including the optional buffer layer 130; however, the description is equally applicable to embodiments not including the optional buffer layer 130.

[0064] refer to Figure 3C, an optional buffer layer 130 is disposed on the capping layer 120. The optional buffer layer 130 has different etching characteristics from the absorption layer subsequently formed thereon, and thus serves as an etching stop layer to prevent damage to the capping layer 120 during the patterning of the absorption layer subsequently formed thereon. In addition, the optional buffer layer 130 can also be used as a sacrificial layer later for focused ion beam repair of defects in the absorption layer. In some embodiments, the optional buffer layer 130 includes ruthenium boride (RuB), ruthenium silicide (RuSi), chromium oxide (CrO) or chromium nitride (CrN). In some other embodiments, the optional buffer layer 130 includes a dielectric material, such as, for example, silicon oxide or silicon oxynitride. In some embodiments, the optional buffer layer 130 is deposited by CVD, PECVD or PVD. In some embodiments, the optional buffer layer has a thickness in the range of about 2nm to 10nm. Embodiments according to the present disclosure are not limited to EUV masks including an optional buffer layer, wherein the optional buffer layer has a thickness from 2nm to about 10nm.

[0065] refer to Figure 2A and Figure 3D According to various embodiments, the method 200 proceeds to operation 208 by depositing an absorber layer 140 over the buffer layer 130 (if present) or on the capping layer 120 (if no buffer layer is present). Figure 3D After depositing the absorber layer 140 over the optional buffer layer 130 according to some embodiments Figure 3C A cross-sectional view of the structure.

[0066] refer to Figure 3D , the absorber layer 140 is disposed in direct contact with the buffer layer 130. When the optional buffer layer 130 is not present, the absorber layer 140 directly contacts the capping layer 120. The absorber layer 140 can be used to absorb radiation of EUV wavelength projected onto the EUV mask 100.

[0067] The absorption layer 140 includes an absorption material having a high extinction coefficient k and a low refractive index n for EUV wavelengths. In some embodiments, the absorption layer 140 includes an absorption material having a high extinction coefficient and a low refractive index at a wavelength of 13.5 nm. In some embodiments, the extinction coefficient k of the absorption material of the absorption layer 140 is greater than 0.01, for example in the range of about 0.01 to 0.08. In some embodiments, the refractive index n of the absorption material of the absorption layer 140 is in the range of 0.87 to 1. According to some embodiments of the present disclosure, the refractive index and the extinction coefficient are related to light with a wavelength of about 13.5 nm. According to some embodiments, the thickness of the absorption layer 140 is less than about 80 nm. According to other embodiments, the thickness of the absorption layer 140 is less than about 60 nm. Other embodiments utilize an absorption layer 140 that is less than about 50 nm.

[0068] In some embodiments, the absorber material is in a polycrystalline state characterized by grains, grain boundaries, and different formed phases. In other embodiments, the absorber material is in an amorphous state characterized by grains of less than 5 nanometers or less than 3 nanometers, no grain boundaries, and a single phase. In some embodiments, the absorber layer 140 includes a first layer of absorber material and a second layer of absorber material different from the first layer of absorber material, wherein the absorber material of the first layer has a refractive index less than about 0.95 and an extinction coefficient greater than 0.01, for example, relative to EUV having a wavelength of about 13.5 nm. In some embodiments, the absorber material of the second layer has similar refractive index and extinction coefficient characteristics. In some embodiments of the present disclosure, the absorber layer 140 includes more than two separate absorber material layers. For example, in some embodiments, the absorber layer 140 includes three, four, or more separate absorber material layers, such as five, six, or even more layers. In some embodiments, the composition of each of the different layers of absorber material is different. In some embodiments including three or more layers of absorber material, the composition of the alternating absorber material layers may be the same, or they may be different. In addition, in some embodiments, the thickness of one or more separate absorber material layers is the same. In other embodiments, the thickness of some or all of the individual absorbent material layers is different. In some embodiments, the thickness of the individual absorbent material layers is between about 20 nm and 50 nm. In other embodiments, the thickness of the individual absorbent material layers is between about 5 nm and 30 nm. In other embodiments, the thickness of the individual absorbent material layers is between about 5 nm and 20 nm.

[0069] In other embodiments, absorbent layer 140 includes a single layer of absorbent material.

[0070] The absorption layer 140 is formed by a deposition technique such as PVD, CVD, ALD, RF magnetron sputtering, DC magnetron sputtering, or IBD. The deposition process may be performed in the presence of an element described as an interstitial element, such as B or N. Deposition in the presence of an interstitial element results in the interstitial element being incorporated into the material of the absorption layer 140.

[0071] Different materials can be used to etch the absorber material of the present disclosure, and in the case of different absorber materials, different materials can be used as the hard mask layer. For example, in some embodiments, a chlorine-containing gas (such as Cl 2 or BCl 3 ) or fluorine-containing gases (such as NF 3 ) dry etching absorption layer 140. Ar can be used as a carrier gas. In some embodiments, oxygen (O 2) as a carrier gas. For example, a chlorine-based etchant, a chlorine-based oxygen etchant, or a mixture of a chlorine-based and a fluorine-based (e.g., carbon tetrafluoride and carbon tetrachloride) etchant will etch the absorbing material, the absorbing material comprising an alloy, the alloy comprising a main alloying element and at least one alloying element, the main alloying element comprising ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt), or gold (Au), the at least one alloying element being selected from ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt), palladium (Pd), tungsten (W), gold (Au), iridium (Ir), niobium (Nb), rhodium (Rh), molybdenum (Mo), hafnium (Hf), or vanadium (V). In some embodiments, the fluorine-based etchant is suitable for etching an alloy, the alloy comprising a main alloying element and at least one alloying element, the main alloying element comprising iridium (Ir), titanium (Ti), niobium (Ni) or rhodium (Rh), the at least one alloying element being selected from boron (B), nitrogen (N), silicon (Si), tantalum (Ta), zirconium (Zr), niobium (Ni), molybdenum (Mo), rhodium (Rh), titanium (Ti) or ruthenium (Ru). In some embodiments, the fluorine-based or fluorine-based oxygen-added etchant is suitable for etching an alloy, the alloy comprising a main alloying element and at least one alloying element, the main alloying element comprising molybdenum (Mo), tungsten (W) or palladium (Pd), the at least one alloying element being selected from ruthenium (Ru), palladium (Pd), tungsten (W), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), silicon (Si) or zirconium (Zr).

[0072] According to some embodiments, SiN, TaBO, TaO, SiO, SiON and SiOB are examples of materials that can be used as hard mask layer 160 and buffer layer 130 of absorption layer 140, and absorption layer 140 utilizes an alloy, the alloy includes a main alloy element and at least one alloy element, the main alloy element includes ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt) or gold (Au), and the at least one alloy element is selected from ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt), palladium (Pd), tungsten (W), gold (Au), iridium (Ir), niobium (Nb), rhodium (Rh), molybdenum (Mo), hafnium (Hf) or vanadium (V). CrO and CrON are examples of materials that can be used for the hard mask layer 160 and the buffer layer 130 of the absorption layer 140, which utilizes an alloy, the alloy including a main alloy element and at least one alloy element, the main alloy element includes iridium (Ir), titanium (Ti), niobium (Ni) or rhodium (Rh), and the at least one alloy element is selected from boron (B), nitrogen (N), silicon (Si), tantalum (Ta), zirconium (Zr), niobium (Ni), molybdenum (Mo), rhodium (Rh), titanium (Ti) or ruthenium (Ru). SiN, TaBO, TaO, CrO, and CrON are examples of materials that can be used for the hard mask layer 160 and the buffer layer 130 of the absorption layer 140, which utilizes an alloy including a main alloying element and at least one alloying element, the main alloying element including molybdenum (Mo), tungsten (W), or palladium (Pd), and the at least one alloying element selected from ruthenium (Ru), palladium (Pd), tungsten (W), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), silicon (Si), or zirconium (Zr). In some embodiments, the same material can be used for the hard mask layer 160 and the buffer layer 130. In other embodiments, the material of the hard mask layer 160 is different from the material of the buffer layer 130. Embodiments according to the present invention are not limited to the above-mentioned types of materials used for the buffer layer 130 and the hard mask layer 160.

[0073] In some embodiments, the absorption layer 140 includes or is made of a Ta-based alloy, which is composed of Ta and at least one alloying element. In some embodiments, the Ta-based alloy is a Ta-rich alloy with a Ta concentration ranging from greater than 50 atomic % to up to 90 atomic %. In other embodiments, the Ta-based alloy is an alloy rich in alloying elements, with a concentration of the alloying element ranging from greater than 50 atomic % to up to 90 atomic %.

[0074] In some embodiments, the Ta-based alloy is composed of Ta and at least one transition metal element. Examples of transition metal elements include, but are not limited to, titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), ruthenium (Ru), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), and gold (Au). In some embodiments, the Ta-based alloy includes tantalum chromium (TaCr), tantalum hafnium (TaHf), tantalum iridium (TaIr), tantalum nickel (TaNi), tantalum ruthenium (TaRu), tantalum cobalt (TaCo), tantalum gold (TaAu), tantalum molybdenum (TaMo), tantalum tungsten (TaW), tantalum iron (TaFe), tantalum rhodium (TaRh), tantalum vanadium (TaV), tantalum niobium (TaNb), tantalum palladium (TaPd), tantalum zirconium (TaZr), tantalum titanium (TaTi), or tantalum platinum (TaPt). Other examples of tantalum-based alloys include nitrides, oxides, borides, and carbides of the above-mentioned examples of tantalum-based alloys, for example, tantalum chromium nitride (TaCrN) or tantalum chromium oxynitride (TiCrON).

[0075] In some embodiments, the Ta-based alloy is further doped with one or more interstitial elements, such as boron (B), carbon (C), nitrogen (N), and oxygen (O). Interstitial element dopants increase the material density, which results in an increase in the strength of the resulting alloy. In some embodiments, the absorption layer 140 consists of Ta, alloying elements, and nitrogen. For example, in some embodiments, the absorption layer 140 includes TaCrN, TaHfN, TaIrN, TaNiN, TaRuN, TaCoN, TaAuN, TaMoN, TaWN, TaFeN, TaRhN, TaVN, TaNbN, TaPdN, TaZrN, TaTiN, TaPtN, or TaSiN. In some embodiments, the absorption layer 140 consists of Ta, alloying elements, nitrogen, and oxygen. For example, in some embodiments, the absorber layer 140 includes TaCrON, TaHfON, TaIrON, TaNiON, TaRuON, TaCoON, TaAuON, TaMoON, TaWON, TaFeON, TaRhON, TaVON, TaNbON, TaPdON, TaZrON, TaTiON, TaPtON, or TaSiON.

[0076] In some embodiments, the absorption layer 140 is deposited as an amorphous layer. By maintaining the amorphous phase, the overall roughness of the absorption layer 140 is improved. The thickness of the absorption layer 140 is controlled to provide 95% to 99.5% absorption of 13.5nm EUV light. In some embodiments, the absorption layer 140 may have a thickness ranging from about 5nm to about 100nm. If the thickness of the absorption layer 140 is too small, the absorption layer 140 cannot absorb a sufficient amount of EUV light to generate a contrast between the reflective area and the non-reflective area. On the other hand, if the thickness of the absorption layer 140 is too large, the accuracy of the pattern formed in the absorption layer 140 may be too low.

[0077] In an embodiment of the present invention, by using an alloy having a high extinction coefficient k according to an embodiment of the present invention as an absorbing material, the mask 3D effect caused by EUV phase distortion can be reduced. Therefore, the optimal focus shift and pattern placement error can be reduced, and the normalized image logarithmic slope (NILS) can be increased.

[0078] refer to Figure 2A and Figure 3E According to some embodiments, method 200 proceeds to operation 210 where a photoresist stack including a hard mask layer 160 and a photoresist layer 170 is deposited over absorber layer 140 . Figure 3E According to some embodiments, a hard mask layer 160 and a photoresist layer 170 are sequentially deposited on the absorption layer 140. Figure 3D A cross-sectional view of the structure.

[0079] refer to Figure 3E , a hard mask layer 160 is disposed above the absorption layer 140. In some embodiments, the hard mask layer 160 is in direct contact with the absorption layer 140. In some embodiments, the hard mask layer 160 includes a dielectric oxide (such as silicon dioxide) or a dielectric nitride (such as silicon nitride). In some embodiments, the hard mask layer 160 is formed using a deposition process, such as, for example, CVD, PECVD, or PVD. In some embodiments, the hard mask layer 160 has a thickness in a range from about 2 nm to 10 nm. Embodiments according to the present disclosure are not limited to a hard mask layer 160 having a thickness in a range from about 2 nm to 10 nm.

[0080] A photoresist layer 170 is disposed over the hard mask layer 160. The photoresist layer 170 includes a photosensitive material operable to be patterned by radiation. In some embodiments, the photoresist layer 170 includes a positive photoresist material, a negative photoresist material, or a hybrid photoresist material. In some embodiments, the photoresist layer 170 is applied to the surface of the hard mask layer 160, for example, by spin coating.

[0081] refer to Figure 2A and Figure 3FAccording to some embodiments, the method 200 proceeds to operation 212 where the photoresist layer 170 is photolithographically patterned to form a patterned photoresist layer 170P. Figure 3F According to some embodiments, after photolithography patterning the photoresist layer 170 to form a patterned photoresist layer 170P Figure 3E A cross-sectional view of the structure.

[0082] refer to Figure 3F , the photoresist layer 170 is patterned by first subjecting the photoresist layer 170 to a pattern of radiation. Next, depending on whether a positive photoresist or a negative photoresist is used in the photoresist layer 170, the exposed portion or the unexposed portion of the photoresist layer 170 is removed with a photoresist developer, thereby forming a patterned photoresist layer 170P having a pattern of openings 172 formed therein. The openings 172 expose portions of the hard mask layer 160. The openings 172 are located in the pattern region 100A, and a pattern corresponding to the openings 152 exists in the EUV mask 100 ( Figure 1A ) in the .

[0083] refer to Figure 2A and Figure 3G According to some embodiments, the method 200 proceeds to operation 214 where the hard mask layer 160 is etched using the patterned photoresist layer 170P as an etch mask to form a patterned hard mask layer 160P. Figure 3G According to some embodiments, after etching the hard mask layer 160 to form the patterned hard mask layer 160P Figure 3F A cross-sectional view of the structure.

[0084] refer to Figure 3G , the portion of the hard mask layer 160 exposed by the opening 172 is etched to form an opening 162 extending through the hard mask layer 160. The opening 162 exposes a portion of the absorber layer 140 below. In some embodiments, the hard mask layer 160 is etched using an anisotropic etch. In some embodiments, the anisotropic etch is a dry etch (such as, for example, a reactive ion etch (RIE)), a wet etch, or a combination thereof. The etch selectively removes the material providing the hard mask layer 160 relative to the material providing the absorber layer 140. The remaining portion of the hard mask layer 160 constitutes the patterned hard mask layer 160P. If not completely consumed during the etching of the hard mask layer 160, after etching the hard mask layer 160, the patterned photoresist layer 170P is removed from the surface of the patterned hard mask layer 160P, for example using wet stripping or plasma ashing.

[0085] refer to Figure 2A and Figure 3HAccording to some embodiments, the method 200 proceeds to operation 216 where the absorption layer 140 is etched using the patterned hard mask layer 160P as an etch mask to form a patterned absorption layer 140P. Figure 3H According to some embodiments, after etching the absorption layer 140 to form the patterned absorption layer 140P Figure 3G A cross-sectional view of the structure.

[0086] refer to Figure 3H , the portion of the absorber layer 140 exposed by the opening 162 is etched to form an opening 142 extending through the absorber layer 140. The opening 142 exposes a portion of the underlying buffer layer 130. In some embodiments, the absorber layer 140 is etched using an anisotropic etching process. In some embodiments, the anisotropic etching is a dry etch (such as, for example, RIE), a wet etch, or a combination thereof, and the anisotropic etching selectively removes the material providing the absorber layer 140 relative to the material providing the underlying buffer layer 130. For example, in some embodiments, a chlorine-containing gas (such as Cl 2 or BCl 3 ) or fluorine-containing gases (such as NF 3 ) to dry etch the absorption layer 140. Ar can be used as a carrier gas. In some embodiments, oxygen (O 2 ) as a carrier gas. The etching rate and etching selectivity depend on the etchant gas, etchant flow rate, power, pressure and substrate temperature. After etching, the remaining portion of the absorption layer 140 constitutes a patterned absorption layer 140P. According to an embodiment of the present disclosure, when the absorption layer 140 includes multiple layers of absorption materials, as described in more detail below, when the individual absorption material layers have different etching characteristics, different etchants can be used to etch the individual absorption material layers separately. When the individual absorption material layers do not have different etching characteristics, the individual absorption material layers can be etched simultaneously.

[0087] refer to Figure 2A and Fig. 3I In accordance with some embodiments, the method 200 continues to operation 218 where the optional buffer layer 130 is etched using the patterned hard mask layer 160P as an etch mask to form a patterned buffer layer 130P. Fig. 3I is after etching the optional buffer layer 130 to form a patterned optional buffer layer 130P according to some embodiments. Figure 3H A cross-sectional view of the structure.

[0088] refer to Fig. 3I, the portion of the buffer layer 130 exposed by the openings 162 and 142 is etched to form an opening 132 extending through the buffer layer 130. The opening 132 exposes a portion of the underlying capping layer 120. In some embodiments, the buffer layer 130 is etched using an anisotropic etching process. In some embodiments, the anisotropic etching is a dry etch (such as, for example, RIE), a wet etch, or a combination thereof, and the anisotropic etching selectively removes the material providing the buffer layer 130 relative to the material providing the capping layer 120. The remaining portion of the buffer layer 130 constitutes the patterned buffer layer 130P. After etching the buffer layer 130, the patterned hard mask layer 160P is removed from the surface of the patterned absorption layer 140P, for example, using oxygen plasma or wet etching.

[0089] The openings 142 in the patterned absorber layer 140P and the corresponding underlying openings 132 in the patterned buffer layer 130P together define the pattern of openings 152 in the EUV mask 100 .

[0090] refer to Figure 2A and Figure 3J According to some embodiments, the method 200 proceeds to operation 220 where a patterned photoresist layer 180P including a pattern of openings 182 is formed over the patterned absorption layer 140P and the patterned buffer layer 130P. Figure 3J According to some embodiments, after forming a patterned photoresist layer 180P including an opening 182 over the patterned absorption layer 140P and the patterned buffer layer 130P Fig. 3I A cross-sectional view of the structure.

[0091] refer to Figure 3J , the opening 182 exposes a portion of the patterned absorption layer 140P at the periphery of the patterned absorption layer 140P. The opening 182 corresponds to the groove 154 to be formed in the peripheral area 100B of the EUV mask 100. In order to form the patterned photoresist layer 180P, a photoresist layer (not shown) is applied over the patterned buffer layer 130P and the patterned absorption layer 140P. The photoresist layer fills the opening 132 in the patterned buffer layer 130P and the opening 142 in the patterned absorption layer 140P, respectively. In some embodiments, the photoresist layer includes a positive photoresist material, a negative photoresist material, or a mixed photoresist material. In some embodiments, the photoresist layer includes the same as described above in Figure 3EIn some embodiments, the photoresist layer includes a material different from the photoresist layer 170. In some embodiments, the photoresist layer is formed, for example, by spin coating. Subsequently, the photoresist layer is patterned by exposing the photoresist layer to a pattern of radiation and removing the exposed or unexposed portions of the photoresist layer using a photoresist developer, depending on whether a positive photoresist or a negative photoresist is used. The remaining portion of the photoresist layer constitutes a patterned photoresist layer 180P.

[0092] refer to Figure 2A and Figure 3K According to some embodiments, the method 200 proceeds to operation 222, where the patterned absorption layer 140P, the patterned buffer layer 130P (if present), the capping layer 120, and the reflective multilayer stack 110 are etched using the patterned photoresist layer 180P as an etching mask to form a groove 154 in the peripheral region 100B of the substrate 102. Figure 3K After etching the patterned absorption layer 140P, the patterned buffer layer 130P (if present), the capping layer 120, and the reflective multilayer stack 110 to form the trench 154 in the peripheral region 100B of the substrate 102 according to some embodiments. Figure 3J A cross-sectional view of the structure.

[0093] refer to Figure 3K The trench 154 extends through the patterned absorption layer 140P, the patterned buffer layer 130P (if present), the capping layer 120, and the reflective multilayer stack 110 to expose the surface of the substrate 102. The trench 154 surrounds the pattern region 100A of the EUV mask 100, separating the pattern region 100A from the peripheral region 100B.

[0094] In some embodiments, the patterned absorption layer 140P, the patterned buffer layer 130P, the capping layer 120, and the reflective multilayer stack 110 are etched using a single anisotropic etching process. The anisotropic etching may be a dry etch (such as, for example, RIE), a wet etch, or a combination thereof, and the anisotropic etching selectively removes the material of the corresponding patterned absorption layer 140P, the patterned buffer layer 130P, the capping layer 120, and the reflective multilayer stack 110 relative to the material providing the substrate 102. In some embodiments, the patterned absorption layer 140P, the patterned buffer layer 130P, the capping layer 120, and the reflective multilayer stack 110 are etched using a plurality of different anisotropic etching processes. Each anisotropic etching may be a dry etch (such as, for example, RIE), a wet etch, or a combination thereof.

[0095] refer to Figure 2A and Figure 3LAccording to some embodiments, the method 200 proceeds to operation 224 where the patterned photoresist layer 180P is removed. Figure 3L According to some embodiments, after removing the patterned photoresist layer 180P Figure 3K A cross-sectional view of the structure.

[0096] refer to Figure 3L The patterned photoresist layer 180P is removed from the pattern region 100A and the peripheral region 100B of the substrate 102, for example, by wet stripping or plasma ashing. The patterned photoresist layer 180P is removed from the opening 142 of the patterned absorption layer 140P and the opening 132 in the patterned buffer layer 130P, exposing the surface of the capping layer 120 in the pattern region 100A again.

[0097] Thus, the EUV mask 100 is formed. The EUV mask 100 includes a substrate 102, a reflective multilayer stack 110 located above the front surface of the substrate 102, a capping layer 120 located above the reflective multilayer stack 110, a patterned buffer layer 130P located above the capping layer 120, and a patterned absorption layer 140P located above the patterned buffer layer 130. The EUV mask 100 also includes a conductive layer 104 over the rear surface of the substrate 102 opposite to the front surface. The patterned absorption layer 140P includes an alloy with a high extinction coefficient, which allows a thinner layer to be formed. Therefore, the mask 3D effect caused by the thicker absorption layer can be reduced, and unnecessary EUV light can be eliminated. As a result, the pattern on the EUV mask 100 can be accurately projected onto a silicon wafer.

[0098] After removing the patterned photoresist layer 180P, the EUV mask 100 is cleaned to remove any contaminants therefrom. In some embodiments, the EUV mask 100 is cleaned by immersing the EUV mask 100 in ammonium hydroxide (NH 4 In some embodiments, the EUV mask 100 is cleaned by immersing the EUV mask 100 in a diluted hydrofluoric acid (HF) solution.

[0099] The EUV mask 100 is then irradiated with UV light, for example, at a wavelength of 193 nm, to inspect any defects in the pattern area 100A. Foreign matter can be detected from the diffusely reflected light. If defects are detected, the EUV mask 100 is further cleaned using a suitable cleaning process.

[0100] like Figure 3M As shown, the pellicle 114 may be positioned over the photomask 100 , thereby forming an enclosed interior volume 207 enclosed by the pellicle 114 and the photomask 100 .

[0101] In some embodiments, the film 114 includes a film frame 209 that can be located on the mask substrate 102. The film frame 209 can be designed to various sizes, shapes, and configurations. In some embodiments, the film frame 209 can have a circular, rectangular, or any other suitable shape. In some embodiments, the film frame 209 can 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 film frame 209 may include a machining process, a sintering process, a photochemical etching process, other applicable processes, or a combination thereof.

[0102] like Figure 3M As further shown, the membrane 114 may also include a vent structure 211 extending through the membrane frame 209. In some embodiments, the vent structure 211 may include one or more holes formed through the membrane frame 209. The holes may take any shape, including circular holes, rectangular holes, slit-shaped holes, other shapes, or any combination thereof. The holes may allow air or other gases to flow through portions of the membrane frame 209. In some embodiments, the holes may include filters to minimize the passage of foreign particles through the vent structure 211. In some embodiments, the vent structure 211 may prevent the membrane from cracking during the EUV lithography process.

[0103] like Figure 3M As further shown, the film frame 209 is attached to the photomask substrate 102 by a film frame adhesive 213. In some embodiments, the film frame adhesive 213 may be formed of a cross-linking adhesive, a thermoplastic elastomer adhesive, a polystyrene adhesive, an acrylic adhesive, a silicone-based adhesive, an epoxy adhesive, or a combination thereof.

[0104] In some embodiments, the film frame 209 may be surface treated to enhance adhesion of the film frame 209 to the film frame adhesive 213. In some examples, the surface treatment may include oxygen plasma treatment, another applicable treatment, or a combination thereof. However, in other examples, the film frame 209 may not be surface treated.

[0105] like Figure 3MAs further shown, the pellicle 114 may also include a pellicle assembly 230 including a pellicle 232 and a membrane border 234 located above the pellicle frame 209. The pellicle 232 extends over the pattern area of ​​the photomask 100 to protect the pattern area from contaminant particles. Particles that are inadvertently deposited on the pattern area of ​​the photomask 100 may introduce defects and cause degradation of the transferred pattern. Particles may be introduced in any of a variety of ways, such as during a cleaning process and / or during processing of the photomask 100. By keeping contaminant particles away from the focal plane of the photomask 100, high-fidelity pattern transfer from the photomask 100 to the semiconductor wafer may be achieved.

[0106] like Figure 3M As shown, the film adhesive 239 can be located between the film boundary 234 and the film frame 209 to attach the film 232 to the film frame 209. In some embodiments, the film adhesive 239 can be formed of a thermoplastic elastomer type adhesive, a polystyrene type adhesive, an acrylic type adhesive, a silicone-based adhesive, an epoxy type adhesive, another suitable adhesive, or a combination thereof. In some embodiments, the film adhesive 239 can be formed of a material different from the material constituting the film frame adhesive 213.

[0107] The film border 234 can be attached around the periphery of the pellicle 232 and thereby mechanically support the pellicle 232. When the pellicle-photomask structure is fully assembled, the film border 234 can in turn be mechanically supported by the upper surface of the pellicle frame 209. That is, the pellicle frame 209 can mechanically support the film border 234 and the pellicle 232 on the substrate 102 of the photomask 100.

[0108] In some embodiments, the membrane boundary 234 may be formed of Si. In further examples, the membrane boundary 234 may be formed of boron carbide, graphene, carbon nanotubes, SiC, SiN, SiO 2 , 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, other suitable materials, allotropes of any of these materials, or combinations thereof.

[0109] Figure 4 is a cross-sectional view of an EUV mask 400 according to a second embodiment of the present disclosure. Figure 4, EUV mask 400 includes substrate 102, reflective multilayer stack 110 located above the front surface of substrate 102, capping layer 120 located above reflective multilayer stack 110, and patterned absorption layer 140P located above capping layer 120. EUV mask 400 also includes conductive layer 104 located above the rear surface of substrate 102 opposite to the front surface. Figure 1A Compared with the EUV mask 100 , the patterned buffer layer 130P is omitted in the EUV mask 400 . Therefore, in the EUV mask 400 , the patterned absorption layer 140P is in direct contact with the capping layer 120 .

[0110] Figure 5 A method 1200 of using an EUV mask according to an embodiment of the present disclosure is shown. The method 1200 includes a step 1202 of exposing the EUV mask to incident radiation. Examples of EUV masks useful in step 1202 include the EUV masks described above. At step 1204, a portion of the incident radiation is absorbed in a patterned absorption layer of the EUV mask, and a portion of the incident radiation that is not absorbed in the patterned absorption layer is directed to a material to be patterned in step 1206. After the material to be patterned is exposed to the incident radiation from the EUV mask, portions of the material that were exposed or not exposed to the incident radiation from the EUV mask are removed in step 1208.

[0111] Figure 2B Steps 227 to 237 are included and involve attaching the membrane frame 209 to the membrane assembly 230 and the substrate 102 . Figure 6 Included in Figure 2B Schematic cross-sectional view of the film frame 209, the film assembly 230 and the substrate 102 during the various steps of FIG. At operation 227, forming and providing Figure 6 In some embodiments, the film frame 209 is formed of a metal material by known techniques. At operation 229, the ends of the film frame 209 to be received by the film adhesive and the film frame adhesive are processed to improve the adhesion between the processed portions of the film frame 209 and the corresponding adhesive. At operation 231, a film adhesive 239 is applied to one end of the film frame 209. Figure 6 The resulting structure is shown in B. Figure 6 In FIG. C, a liner 241 has been applied to the exposed portion of the film adhesive 239 to prevent the film adhesive 239 from adhering to unwanted materials. Figure 6 The film frame 209 is flipped over as shown in D in FIG. 2 and then according to operation 233, the film frame adhesive 213 is applied to the opposite end of the film frame 209. Figure 6In F, a liner 243 has been applied to the exposed portion of the film frame adhesive 213. After operation 233, the film frame 209 including the two adhesive layers is turned over. Figure 6 In G in FIG. , a flipped film frame including two adhesive layers is shown. Figure 6 In the H in FIG. 2 , the liner 241 has been removed. At operation 235, the exposed portion of the film adhesive 239 contacts the film boundary 234 of the support film 232. The film boundary 234 and the film 232 are formed by known techniques, such as growth of a silicon substrate, forming a film on the silicon substrate, and backside etching of the silicon substrate to reduce the portion of the silicon substrate under the film. Figure 6 1 in FIG. 2 shows a film border 234 attached to a film adhesive 239 . Figure 6 FIG. 2 shows the film frame 209 after the liner 243 is removed. After the liner 243 is removed, at operation 237, the film frame carrying the film assembly is contacted with the substrate 102. The adhesive 213 attaches the film frame 209 to the substrate 102. Figure 6 In some embodiments, the film frame carrying the film assembly is attached to the substrate 102 using a precision mounting machine.

[0112] One aspect of the present specification relates to an EUV mask including a substrate and a reflective multilayer stack located above the substrate. In this aspect of the EUV mask, a patterned absorber layer is located above the reflective multilayer stack, and a pellicle frame is located on the substrate.

[0113] In some embodiments, the EUV mask further includes a film frame adhesive between the film frame and the substrate.

[0114] In some embodiments, the film frame adhesive contacts the film frame and contacts the substrate.

[0115] In some embodiments, the pellicle frame adhesive contacts the pellicle frame and contacts the substrate, and the EUV mask further includes a pellicle assembly located over the pellicle frame.

[0116] In some embodiments, the EUV mask further includes a film adhesive located between the film assembly and the film frame.

[0117] In some embodiments, the EUV mask further includes a film adhesive between the film assembly and the film frame, wherein the film adhesive contacts a film boundary of the film assembly and contacts the film frame.

[0118] In some embodiments, the EUV mask further includes a capping layer over the reflective multilayer stack.

[0119] In some embodiments, the EUV mask further includes a capping layer over the reflective multilayer stack, and further includes trenches in the reflective multilayer stack, the capping layer, and the patterned absorption layer.

[0120] In some embodiments, the EUV mask further comprises a cover layer over the reflective multilayer stack, and further comprises grooves in the reflective multilayer stack, the cover layer, and the patterned absorption layer, wherein the film frame is attached to the substrate in the grooves.

[0121] In some embodiments, the extreme ultraviolet mask also includes a cover layer located above the reflective multilayer stack, and also includes a groove located in the reflective multilayer stack, the cover layer and the patterned absorption layer, wherein the film frame is attached to the substrate in the groove, the groove includes a sidewall, and the sidewall is inclined.

[0122] In some embodiments, the membrane frame includes a vent through the membrane frame.

[0123] In some embodiments, the EUV mask further includes a film frame adhesive between the film frame and the substrate, and further includes an anti-thermal conductive layer located above the substrate and below the film frame adhesive.

[0124] In some embodiments, the EUV mask further comprises a cover layer over the reflective multilayer stack, and further comprises grooves in the reflective multilayer stack, the cover layer, and the patterned absorption layer, wherein a ratio of a width X of the groove to a width Y of the film frame is between 1.1:1 and 4:1.

[0125] In some embodiments, the thin film frame does not overlap the reflective multilayer stack.

[0126] Another aspect of the present specification relates to a method for using an EUV mask. The method includes exposing the EUV mask to incident radiation, the EUV mask including a substrate and a reflective multilayer stack located above the substrate. The EUV mask also includes a patterned absorber layer located above the reflective multilayer stack and grooves located in the reflective multilayer stack and the patterned absorber layer. A film frame bonding layer is located on the substrate and at the bottom of the groove, and a film frame is located on the film frame bonding layer. The method includes absorbing a portion of the incident radiation in the patterned absorber layer, and blocking a portion of the incident radiation from reaching the film frame bonding layer at the bottom of the groove through one or more of the patterned absorber layer or the reflective multilayer stack.

[0127] In some embodiments, the method further includes conducting thermal energy to the film frame adhesive layer in the bottom of the trench through a thermal barrier layer.

[0128] In some embodiments, the method further comprises conducting thermal energy to the film frame adhesive layer in the bottom of the trench through a thermal barrier layer comprising silicon or silicon dioxide.

[0129] Another aspect of the present specification relates to a method for forming an EUV mask. The method includes forming a reflective multilayer stack on a substrate and depositing a capping layer on the reflective multilayer stack. According to the method, a buffer layer is formed on the capping layer, and an absorbing material layer is deposited on the buffer layer. A hard mask layer is formed on the absorbing material layer. The hard mask layer is etched to form a patterned hard mask layer. The absorbing material layer is etched using the patterned hard mask layer as an etching mask. The etching produces a plurality of openings in the absorbing material layer. The patterned hard mask layer is then removed, and grooves are formed in the absorbing material layer, the buffer layer, the capping layer, and the reflective multilayer stack. According to the method, a film frame is then attached to the substrate in the groove.

[0130] In some embodiments, forming grooves in the absorption material layer, the buffer layer, the covering layer and the reflective multilayer stack includes: forming a patterned mask on the patterned absorption layer, and etching the absorption material layer, the buffer layer, the covering layer and the reflective multilayer stack through openings in the patterned mask.

[0131] In some embodiments, attaching a film frame to the substrate in the trench includes contacting the film frame and the substrate in the trench with a film frame adhesive at the bottom of the trench.

[0132] The features of several embodiments are summarized above so that those skilled in the art can better understand aspects of the present disclosure. Those skilled in the art should understand that they can easily use the present disclosure as a basis to design or modify other processes and structures for implementing the same purpose and / or achieving the same advantages as the embodiments introduced herein. Those skilled in the art should also appreciate that such equivalent constructions do not deviate from the spirit and scope of the present disclosure, and that they can make various changes, substitutions, and modifications herein without departing from the spirit and scope of the present disclosure.

Claims

1. An extreme ultraviolet (EUV) mask, comprising: substrate; a reflective multilayer stack located above the substrate; a patterned absorber layer disposed above the reflective multilayer stack; as well as The film frame is located on the substrate. 2 . The EUV mask of claim 1 , further comprising a film frame adhesive between the film frame and the substrate.

3. The EUV mask according to claim 2, wherein: The film frame adhesive contacts the film frame and contacts the substrate.

4. The EUV mask of claim 1, further comprising a film assembly located above the film frame. 5 . The EUV mask of claim 4 , further comprising a film adhesive between the film assembly and the film frame.

6. The EUV mask according to claim 5, wherein: The film adhesive contacts a film boundary of the film assembly and contacts the film frame.

7. The EUV mask of claim 1, further comprising a capping layer over the reflective multilayer stack.

8. The EUV mask of claim 7, further comprising grooves in the reflective multilayer stack, the capping layer, and the patterned absorbing layer.

9. A method of using an extreme ultraviolet mask, the method comprising: Exposing the EUV mask to incident radiation, the EUV mask comprising: substrate; a reflective multilayer stack located above the substrate; a patterned absorber layer disposed above the reflective multilayer stack; a groove in the reflective multilayer stack and the patterned absorber layer; a thin film frame adhesive layer on the substrate and at the bottom of the groove; and a film frame, located on the film frame adhesive layer; absorbing a portion of the incident radiation in the patterned absorbing layer; A portion of the incident radiation is blocked from reaching the film-frame adhesive layer at the bottom of the trench by one or more of the patterned absorber layer or the reflective multilayer stack.

10. A method of forming an extreme ultraviolet (EUV) mask, comprising: forming a reflective multilayer stack on a substrate; depositing a capping layer on the reflective multilayer stack; forming a buffer layer on the cover layer; depositing an absorbent material layer on the buffer layer; forming a hard mask layer on the absorber material layer; etching the hard mask layer to form a patterned hard mask layer; etching the absorbent material layer to form a plurality of openings therein using the patterned hard mask layer as an etch mask; removing the patterned hard mask layer; forming grooves in the absorbent material layer, the buffer layer, the cover layer, and the reflective multilayer stack; A thin film frame is attached to the substrate in the trench.

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