EUV Transmission Research Articles

Сравнительное исследование термостойкости пелликлов на основе бериллия

We demonstrate the possibility of manufacturing Be-based ultrathin films with high transmission at wavelengths of 11.4 and 13.5 nm. For free-standing films of Be and Be-based multilayer structures (Si/Be, ZrSi2/Be, Be/BexNy, Zr/Be, Ru/Be, Mo/Be), we determine the thresholds of the absorbed power at which over a short period (tens of minutes) of vacuum annealing, initially sagging free-standing films became visibly stretched over the hole. Of the film structures tested here, the Be/BexNy structure (with beryllium nitride interlayers) showed the highest threshold for the absorbed power (1 W/cm2). However, due to the low strength of this structure, ZrSi2/Be, Mo/Be, and Be films seem to be more promising for the manufacture of a full-size pellicle. Long-term vacuum annealing of Mo/Be and Be ultrathin films showed that they could withstand 24 hours of vacuum heating at an absorbed power density of 0.2 W/cm2 (film temperature ~250°C) without noticeable changes in EUV transmission or sagging of films. With comparable transmission (~83% at 13.5 nm and ~88% at 11.4 nm), a multilayer Mo/Be structure with a thickness of 30 nm appears to be preferable, as it shows less brittleness than a monolayer Be film with a thickness of 50 nm.

Comparative study of the thermal stability of Be-based extremeultraviolet pellicles

We demonstrate the possibility of manufacturing Be-basedultrathin films with high transmission at wavelengths of 11.4 and 13.5 nm. For free-standing films of Be and Be-based multilayer structures (Si/Be,ZrSi2/Be, Be/BexNy, Zr/Be, Ru/Be, Mo/Be), we determine the thresholds of theabsorbed power at which over a short period (tens of minutes) of vacuumannealing, initially sagging free-standing films became visibly stretchedover the hole. Of the film structures tested here, the Be/BexNy structure(with beryllium nitride interlayers) showed the highest threshold for theabsorbed power (1 W/cm2). However, due to the low strength of thisstructure, ZrSi2/Be, Mo/Be, and Be films seem to be more promising for themanufacture of a full-size pellicle. Long-term vacuum annealing of Mo/Beand Be ultrathin films showed that they could withstand 24 hours of vacuumheating at an absorbed power density of 0.2 W/cm2 (film temperature 250oC)without noticeable changes in EUV transmission or sagging of films. Withcomparable transmission (~83% at 13.5 nm and ~88% at 11.4 nm), a multilayerMo/Be structure with a thickness of 30 nm appears to be preferable, as itshows less brittleness than a monolayer Be film with a thickness of 50 nm. Keywords: Be-based pellicle, multilayer thin film, EUV lithography,thermal stability\

EUV interferometric lithography and structural characterization of an EUV diffraction grating with nondestructive spectroscopic ellipsometry

In this study, we constructed an exposure platform to perform extreme ultraviolet interferometric lithography (EUVIL) exposure. This platform can be used to expose 1D and 2D gratings, simulating the line/space and contact/hole patterns, respectively. A transmission grating and an achromatic setup were utilized in the exposure. A simple and nondestructive optical characterization approach based on spectroscopic ellipsometry was proposed to characterize the structure of an EUV transmission grating. The optical behavior of a grating was analyzed by rigorous coupled-wave analysis (RCWA). The preliminary exposure results were obtained using the constructed exposure platform.

Polarization performance of EUV transmission multilayers as λ/4 and λ/2 plates at a photon energy of 97 eV

Abstract Complex relative amplitude transmittance ρ = T p /T s of extreme ultraviolet transmission multilayers fabricated to three numbers of layers has been evaluated by ellipsometry with synchrotron radiation at a photon energy of 97 eV. Large phase shifts enough to be a quarter-wave plate and a half-wave plate have been observed with respective transmittances of 10 and 0.5%.

EUV and soft x-ray transmission microscope (abstract)

We present preliminary performance results for a new type of imaging microscope operating in the EUV and soft x-ray regions. This microscope is a true transmission microscope in which an unmagnified image of the sample is formed by differential absorption of the x-ray beam as it passes through the sample. The unmagnified photon image is converted into low energy secondary electrons at a thin CsI photocathode, and the subsequent electron pattern is magnified and imaged using a simple 3-lens system. Conversion of the magnified electron patern into visible photons occurs at a fine grain phosphor viewed by a CCD detector/computer combination that allows parallel detection of the original photon image in near real time with approximately 1000× magnification. The microscope has a theoretical resolution of 20 nm and a potentially wide range of uses including biology, materials science studies, and investigations into magnetic dichroism effects. The design and preliminary imaging results of the microscope will be presented and future directions discussed.