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US-20260126716-A1 - EXTREME ULTRAVIOLET MASK WITH ALLOY BASED ABSORBERS

US20260126716A1US 20260126716 A1US20260126716 A1US 20260126716A1US-20260126716-A1

Abstract

An extreme ultraviolet mask including a substrate, a reflective multilayer stack on the substrate and a multi-layer patterned absorber layer on the reflective multilayer stack is provided. Disclosed embodiments include an absorber layer that includes an alloy comprising ruthenium (Ru), chromium (Cr), 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. The at least one alloying element includes ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt), 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). Other embodiments include a multi-layer patterned absorber structure with layers that include an alloy and an alloying element, where at least two of the layers of the multi-layer structure have different compositions.

Inventors

  • Pei-Cheng Hsu
  • Ping-Hsun LIN
  • Hsin-Chang Lee
  • Ta-Cheng Lien

Assignees

  • TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.

Dates

Publication Date
20260507
Application Date
20251229

Claims (20)

  1. 1 . A method of forming an extreme ultraviolet (EUV) mask, comprising: depositing a reflective multilayer stack over a substrate; deposing a capping layer over the reflective multilayer stack; and forming at least one EUV absorber layer over the capping layer, wherein the at least one EUV absorber layer comprises a tantalum (Ta)-based alloy comprised of Ta and at least one alloying element selected from titanium (Ti), chromium (Cr), iron (Fe), ruthenium (Ru), cobalt (Co), molybdenum (Mo), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), gold (Au), tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V), or a nitride, oxide, oxynitride, boride or carbide of the Ta-based alloy thereof; and etching the at least one EUV absorber layer to form at least one patterned EUV absorber layer, exposing portions of the capping layer.
  2. 2 . The method of claim 1 , wherein etching the at least one EUV absorber layer comprises: depositing a hard mask layer over the at least one EUV absorber layer; forming a photoresist layer over the hard mask layer; patterning the photoresist layer to form a patterned photoresist layer comprising a pattern of openings; forming a patterned hard mask layer using the patterned photoresist layer as an etch mask; and removing portions of the at least one EUV absorber layer not covered by the patterned hard mask layer.
  3. 3 . The method of claim 2 , wherein at least one EUV absorber layer comprises a first layer of a first absorber material and a second layer of a second absorber material different from the first absorber material, wherein the first absorber material and the second absorber material are independently composed of the Ta-based alloy or a nitride, oxide, oxynitride, boride or carbide of the Ta-based alloy thereof, wherein etching the at least one absorber layer comprises etching the first layer of the first absorber material and the second layer of the second absorber material.
  4. 4 . The method of claim 3 , wherein the at least one EUV absorber layer further comprises a third layer of a third absorber material, the third absorber material of the third layer selected from an alloy comprising ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt) or gold (Au), and at least one alloying element 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), wherein etching the at least one absorber layer further comprises etching the third layer of the third absorber material.
  5. 5 . The method of claim 4 , wherein the at least one EUV absorber layer further comprises a fourth layer of a fourth absorber material, the fourth absorber material of the fourth layer selected from an alloy comprising ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt) or gold (Au), and at least one alloying element 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), wherein etching the at least one absorber layer further comprises etching the fourth layer of the fourth absorber material.
  6. 6 . The method of claim 2 , wherein at least one EUV absorber layer further comprises a third layer of third absorber material, the third absorber material of the third layer selected from an alloy comprising 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), tantalum (Ta), palladium (Pd), tungsten (W), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), boron (B), nitrogen (N), silicon (Si) or zirconium (Zr), wherein etching the at least one absorber layer further comprises etching the third layer of the third absorber material.
  7. 7 . The method of claim 6 , wherein the at least one EUV absorber layer further comprises a fourth layer of a fourth absorber material, the fourth absorber material of the fourth layer selected from an alloy comprising 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), tantalum (Ta), palladium (Pd), tungsten (W), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), boron (B), nitrogen (N), silicon (Si) or zirconium (Zr), wherein etching the at least one absorber layer further comprises etching the fourth layer of the fourth absorber material.
  8. 8 . The method of claim 1 , wherein the Ta-based alloy further comprises at least one interstitial element selected from nitrogen (N), oxygen (O), boron (B), carbon (C) or combinations thereof.
  9. 9 . The method of claim 1 , further comprising depositing a buffer layer over the capping layer prior to forming the at least one EUV absorber layer.
  10. 10 . The method of claim 9 , further comprising etching the buffer layer using the at least one patterned EUV absorber layer as an etch mask.
  11. 11 . A method of forming an extreme ultraviolet (EUV) mask, comprising: forming a reflective multilayer stack over a substrate; forming an absorber layer over the reflective multilayer stack, wherein the absorber layer includes a first layer of a first absorber material and a second layer of a second absorber material different from the first absorber material, the first absorber material and the second absorber material independently comprising an alloy including one or more of niobium (Nb), rhodium (Rh) or tungsten (W) and at least one alloying element selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V), the first absorber material having an index of refraction smaller than 0.95 and an extinction coefficient greater than 0.01; and etching the absorber layer to form a patterned absorber layer.
  12. 12 . The method of claim 11 , wherein the first absorber material comprises an alloy including one or more of niobium (Nb), rhodium (Rh) or tungsten (W), and at least two alloying elements selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V).
  13. 13 . The method of claim 11 , wherein the second absorber material comprises an alloy including niobium (Nb), rhodium (Rh) or tungsten (W), and at least two alloying elements selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V).
  14. 14 . The method of claim 11 , further comprising depositing a capping layer over the reflective multilayer stack prior to forming the absorber layer.
  15. 15 . The method of claim 14 , wherein depositing the capping layer comprises depositing 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) or technetium (Tc) over the second layer of the second absorber material.
  16. 16 . The method of claim 11 , wherein the first layer of the first absorber material and the second layer of the second absorber material are etched simultaneously or etched individually using different etchants.
  17. 17 . 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 capping layer; depositing a first layer of absorber material on the buffer layer, wherein the absorber material of the first layer includes an alloy comprising 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 is 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); depositing a second layer of absorber material on the first layer of absorber material, wherein the absorber material of the second layer is different from the absorber material of the first layer includes an alloy comprising 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 is 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); forming a hard mask layer on the second layer of absorber material; etching the hard mask layer to form a patterned hard mask layer; and etching the first layer of absorber material to form a plurality of openings therein using the patterned hard mask layer as an etch mask.
  18. 18 . The method of claim 17 , further comprising etching the second layer of absorber material to form a plurality of openings therein using the patterned hard mask layer as an etch mask.
  19. 19 . The method of claim 18 , wherein the etching of the first layer of absorbent material and the etching of the second layer of absorbent material occur in a single etching step.
  20. 20 . The method of claim 17 , wherein depositing the first layer of absorbent material and the second layer of absorbent material forms an amorphous first layer of absorbent material and an amorphous second layer of absorbent material.

Description

BACKGROUND The semiconductor industry has experienced exponential growth. Technological advances in materials and design have produced generations of integrated circuits (ICs), where each generation has smaller and more complex circuits than the previous generation. In the course of 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 fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. FIG. 1 is a cross-sectional view of an extreme ultraviolet (EUV) mask, in accordance with a first embodiment. FIG. 2 is a flowchart of a method for fabricating the EUV mask of FIG. 1, in accordance with some embodiments. FIGS. 3A-3L are cross-sectional views of an EUV mask at various stages of the fabrication process of FIG. 2, in accordance with some embodiments. FIG. 4 is a cross-sectional view of an extreme ultraviolet (EUV) mask, in accordance with a second embodiment. FIG. 5 is a flowchart of a method for fabricating the EUV mask of FIG. 4, in accordance with some embodiments. FIGS. 6A-6J are cross-sectional views of an EUV mask at various stages of the fabrication process of FIG. 5, in accordance with some embodiments. FIG. 7 is a cross-sectional view of an extreme ultraviolet (EUV) mask including a single layer of absorber material at an intermediate stage of manufacture in accordance with some embodiments. FIG. 8 is a cross-sectional view of an extreme ultraviolet (EUV) mask including two layers of absorber material at an intermediate stage of manufacture in accordance with some embodiments. FIG. 9 is a cross-sectional view of an extreme ultraviolet (EUV) mask including three layers of absorber material at an intermediate stage of manufacture in accordance with some embodiments. FIG. 10 is a cross-sectional view of an extreme ultraviolet (EUV) mask including four layers of absorber material at an intermediate stage of manufacture in accordance with some embodiments. FIG. 11 is a flowchart of a method of using an EUV mask in accordance with some embodiments. DETAILED DESCRIPTION The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. In the manufacture of integrated circuits (ICs), patterns representing different layers of the ICs are fabricated using a series of reusable photomasks (also referred to herein as photolithography masks or masks) in order to transfer the design of each layer of the ICs onto a semiconductor substrate during the semiconductor device fabrication process. With the shrinkage in IC size, extreme ultraviolet (EUV) light with a wavelength of 13.5 nm is employed in, for example, a lithographic process to enable transfer of very small patterns (e.g., nanometer-scale patterns) from a mask to a semiconductor wafer. Because most materials are highly absorbing at the wavelength of 13.5 nm, EUV lithography utilizes a reflective-type EUV mask having a ref