Speaker: Iwao Nishiyama, Semiconductor Leading Edge Technologies (SELETE), Japan
Date & Time: May 10, 2007 - 11:00am
Location: Chem 260
Atomic Hydrogen Cleaning of Ru capped multilayer-mirrors for extreme ultraviolet lithography (EUVL)
Laboratory for Surface Modification
Iwao Nishiyama, Semiconductor Leading Edge Technologies (SELETE), Japan,
11:00 AM, Chem 260
Contamination control is very important for EUV multilayer mirrors, since the projection optics in EUV lithography require a very long reflectivity lifetime under strong EUV irradiation in a partial vacuum. The primary sources of contamination that degrade reflectivity are: (1) carbon contamination produced by the photodecomposition of background organic molecules, and (2) surface oxidation of the capping layer caused by a reaction with background H2O induced by EUV radiation. We developped an atomic hydrogen cleaning technology which is applicable both for two major contamination sources. In the talk, we present (1) surface composition change of a Ru-capped mirror measured by XPS and AES before and after treatment. (2) EUV reflectivity change caused by carbon contamnation and oxidation measured before and after cleaning, (3) Cleaning technology using atomic hydrogen transported through quartz tube. (4) Measurement of atomic hydrogen density using Lyman-alpha absorption spectroscopy. As time permits, the author will give an overview of Japanese EUV Lithography development activity.