Ru-capped extreme ultraviolet lithography photomasks require cleaning after patterning of the absorber layer. In this study, it was confirmed that, during Cl 2 dry etching to remove the absorber layer, RuCl 3 was formed on the Ru capping layer surface, and the surface roughness thereby deteriorated. Therefore, the changes in RuCl 3 formation and surface roughness with various cleaning processes were investigated. Among the treatments used, i.e., sulfuric peroxide mixture, an ammonia peroxide mixture or ozonated water (DIO 3 ), DIO 3 exhibited the most effective Cl removal efficiency and surface roughness recovery. DIO 3 treatment successfully reduced the Cl-terminated Ru surface to its original state and decreased the surface roughness to the pre-Cl 2 -etched Ru value.
Bibliographical noteFunding Information:
This work was supported by Hynix Semiconductor Inc. This work was also supported by the Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2009-0093823 ).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films