Extreme ultraviolet lithography mask patterning and printability studies with a Ta-based absorber
- 1 November 1999
- journal article
- Published by American Vacuum Society in Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures
- Vol. 17 (6), 3029-3033
- https://doi.org/10.1116/1.590948
Abstract
Extreme ultraviolet (EUV) lithography masks were fabricated using a stack of TaSi or TaSiN (absorber), SiON (repair buffer), and Cr (conductive etch stop) on a Mo/Si multilayer mirror deposited on a Si wafer. High-resolution structures were exposed using a commercial i-line resist, and the pattern was transferred using both electron cyclotron resonance and reactive ion etching with halogen-based gases. Process temperatures to fabricate these reticles were always maintained below 150 °C. EUV properties after patterning were measured using a synchrotron source reflectometer. Completed masks exhibited a negligible shift in the peak wavelength and less than 2% loss in reflectivity due to processing. Qualified masks were exposed with a 10× EUV exposure system. The exposures were made in 80-nm-thick DUV resist and with numerical apertures (NA) of 0.08, 0.088, and 0.1. Resolution down to 70 nm equal lines and spaces was achieved at a NA of 0.1. Line edge roughness in the resist features was 5.5 nm (3σ, one side), and the depth of focus for ±10% CD control was ±1 μm for 100 nm equal lines and spaces.Keywords
This publication has 17 references indexed in Scilit:
- Low-defect reflective mask blanks for extreme ultraviolet lithographyPublished by SPIE-Intl Soc Optical Eng ,1999
- EUV mask patterning approachesPublished by SPIE-Intl Soc Optical Eng ,1999
- Extreme ultraviolet lithographyJournal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1998
- Scattering with angular limitation projection electron beam lithography for suboptical lithographyJournal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1997
- X-ray lithography: Status, challenges, and outlook for 0.13 μmJournal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1997
- Uniform low stress oxynitride films for application as hardmasks on x-ray masksJournal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1997
- Modeling of in-plane distortions due to variations in absorber stressMicroelectronic Engineering, 1996
- Etch characteristics of an amorphous refractory absorberMicroelectronic Engineering, 1996
- Method for fabricating a low stress x-ray mask using annealable amorphous refractory compoundsJournal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1995
- X-Ray Interactions: Photoabsorption, Scattering, Transmission, and Reflection at E = 50-30,000 eV, Z = 1-92Atomic Data and Nuclear Data Tables, 1993