Abstract: The present disclosure describes a method of patterning a semiconductor wafer using extreme ultraviolet lithography (EUVL). The method includes receiving an EUVL mask that includes a substrate having a low temperature expansion material, a reflective multilayer over the substrate, a capping layer over the reflective multilayer, and an absorber layer over the capping layer. The method further includes patterning the absorber layer to form a trench on the EUVL mask, wherein the trench has a first width above a target width. The method further includes treating the EUVL mask with oxygen plasma to reduce the trench to a second width, wherein the second width is below the target width. The method may also include treating the EUVL mask with nitrogen plasma to protect the capping layer, wherein the treating of the EUVL mask with the nitrogen plasma expands the trench to a third width at the target width.

Abstract: A system includes a mask. The system further includes a pellicle frame attached to the mask. The pellicle frame includes a check valve, wherein the check valve is configured to permit gas flow from a first side of the pellicle from to a second side of the pellicle frame. The pellicle frame further includes a flat bottom surface having only a single recess therein, wherein the flat bottom surface is free of an adhesive. The system further includes a gasket within the single recess.

Abstract: A pellicle for an extreme ultraviolet (EUV) photomask includes a pellicle frame and a main membrane attached to the pellicle frame. The main membrane includes a plurality of nanotubes, and each of the plurality of nanotubes is covered by a coating layer containing Si and one or more metal elements.

Abstract: In a method of cleaning a photo mask, the photo mask is placed on a support such that a pattered surface faces down, and an adhesive sheet is applied to edges of a backside surface of the photo mask.

Abstract: A method includes forming a test pattern and a reference pattern in an absorption layer of a photomask structure. The test pattern has a first trench and a second trench, the reference pattern has a third trench and a fourth trench, the test pattern and the reference pattern have substantially the same dimension in a top view, and the second trench is deeper than the first trench, the third trench, and the fourth trench. The method further includes emitting a light beam to the test pattern to obtain a first interference pattern reflected from the test pattern, emitting the light beam to the reference pattern to obtain a second interference pattern reflected from the reference pattern; and comparing the first interference pattern with the second interference pattern to obtain a measured complex refractive index of the absorption layer.

Abstract: In a method of manufacturing a pellicle for an extreme ultraviolet (EUV) photomask, a nanotube layer including a plurality of carbon nanotubes is formed, the nanotube layer is attached to a pellicle frame, and a solvent dipping treatment is performed to the nanotube layer by applying bubbles in a solvent to the nanotube layer.

Abstract: A reflective mask includes a reflective multilayer over a substrate, a capping layer over the reflective multilayer, an absorber layer over the capping layer and including a top surface, and a protection layer directly on the top surface of the absorber layer. The absorber layer is formed of a first material and the protection layer is formed of a second material that is less easily to be oxidized than the first material.

Abstract: A method includes performing a lithography process using a mask and a pellicle membrane; detaching the pellicle membrane from the mask after the lithography process is completed; performing an inspection process to the pellicle membrane, the inspection process including generating a laser beam toward the pellicle membrane from a laser source, such that the laser beam passes through the pellicle membrane; and generating an image by receiving the laser beam passing through the pellicle membrane using an image sensor; and determining whether a particle is present on the pellicle membrane or a pin hole is present in the pellicle membrane based on the image.

Abstract: A method includes forming a reflective multilayer over a substrate; depositing a first capping layer over the reflective multilayer, wherein the first capping layer is made of a ruthenium-containing material or a chromium-containing material; performing a treatment to the first capping layer to introduce nitrogen or fluorine into the first capping layer; forming an absorption layer over the first capping layer; and patterning the absorption layer.

Abstract: An extreme ultraviolet (EUV) mask includes a substrate, a reflective multilayer stack on the substrate, a diffusion barrier layer, a capping layer and a patterned absorber layer. The reflective multilayer stack comprises alternately stacked first layers and second layers. The diffusion barrier layer is on the reflective multilayer stack. The diffusion barrier layer has a composition different from compositions of the first layers and the second layers. The capping layer is on the diffusion barrier layer. The patterned absorber layer is on the reflective multilayer stack.

Abstract: In a method of manufacturing a pellicle for an extreme ultraviolet (EUV) photomask, a nanotube layer including a plurality of carbon nanotubes is formed, the nanotube layer is attached to a pellicle frame, and a Joule hearting treatment is performed to the nanotube layer by applying electric current through the nanotube layer.

Abstract: In a method of manufacturing a pellicle for an extreme ultraviolet (EUV) photomask, a membrane of Sp2 carbon is formed, a treatment is performed on the membrane to change a surface property of the membrane, and after the treatment, a cover layer is formed over the membrane.

Abstract: A pellicle frame includes a check valve, wherein the check valve is configured to permit gas flow from an interior of the pellicle to an exterior of the pellicle. The pellicle frame further includes a bottom surface of the frame defines only a single recess therein. The pellicle frame further includes a gasket configured to fit within the single recess.

Abstract: A pellicle assembly includes a pellicle membrane with a nanotube layer formed from thick nanotube bundles. The pellicle membrane can be formed with multiple layers and has a combination of long lifetime, high transmittance, low deflection, and small pore size. A conformal coating may applied to an outer surface of the pellicle membrane. The conformal coating protects the pellicle membrane from damage that can occur due to heat and hydrogen plasma created during EUV exposure.

Abstract: An extreme ultraviolet mask including a substrate, a reflective multilayer stack on the substrate and a patterned absorber layer on the reflective multilayer stack is provided. The patterned absorber layer includes an alloy comprising tantalum and at least one alloying element. The at least one alloying element includes at least one transition metal element or at least one Group 14 element.

Abstract: In a method of cleaning a photo mask, the photo mask is placed on a support such that a pattered surface faces down, and an adhesive sheet is applied to edges of a backside surface of the photo mask.

Abstract: A lithography mask includes a substrate, a reflective structure disposed over a first side of the substrate, and a patterned absorber layer disposed over the reflective structure. The lithography mask includes a first region and a second region that surrounds the first region in a top view. The patterned absorber layer is located in the first region. A substantially non-reflective material is located in the second region. The lithography mask is formed by forming a reflective structure over a substrate, forming an absorber layer over the reflective structure, defining a first region of the lithography mask, and defining a second region of the lithography mask. The defining of the first region includes patterning the absorber layer. The second region is defined to surround the first region in a top view. The defining of the second region includes forming a substantially non-reflective material in the second region.

Abstract: Coated nanotubes and bundles of nanotubes are formed into membranes useful in optical assemblies in EUV photolithography systems. These optical assemblies are useful in methods for patterning materials on a semiconductor substrate. Such methods involve generating, in a UV lithography system, UV radiation. The UV radiation is passed through a coating layer of the optical assembly, e.g., a pellicle assembly. The UV radiation that has passed through the coating layer is passed through a matrix of individual nanotubes or matrix of nanotube bundles. UV radiation that passes through the matrix of individual nanotubes or matrix of nanotube bundles is reflected from a mask and received at a semiconductor substrate.

Abstract: A method of forming a pellicle includes forming a protective film surrounding a membrane to form a pellicle membrane using a plasma enhanced atomic layer deposition (PEALD) process, in which the membrane includes a network of carbon nanotubes, the PEALD process is performed by a plurality of cycles, and each of the cycles includes igniting a plasma in a deposition chamber, after igniting the plasma, introducing a silicon-based precursor into the deposition chamber, purging the silicon-based precursor, introducing a reactant gas into the deposition chamber, and purging the reactant gas, placing the pellicle membrane on a filter membrane, transferring the pellicle membrane from the filter membrane to a pellicle border, attaching the pellicle border to a pellicle frame, and mounting the pellicle frame onto a photomask comprising a pattern region.

Abstract: In a method of manufacturing a reflective mask, a photo resist layer is formed over a mask blank. The mask blank includes a substrate, a reflective multilayer on the substrate, a capping layer on the reflective multilayer, an absorber layer on the capping layer and a hard mask layer, and the absorber layer is made of Cr, CrO or CrON. The photo resist layer is patterned, the hard mask layer is patterned by using the patterned photo resist layer, the absorber layer is patterned by using the patterned hard mask layer, and an additional element is introduced into the patterned absorber layer to form a converted absorber layer.