Extreme ultraviolet mask with alloy based absorbers

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.

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.