New Results from DUV Water Immersion Microscopy Using the CD Metrology System LWM500 WI with a High NA Condenser
Conference: EMLC 2008 - 24th European Mask and Lithography Conference
01/21/2008 - 01/24/2008 at Dresden, Germany
Proceedings: EMLC 2008
Pages: 6Language: englishTyp: PDFPersonal VDE Members are entitled to a 10% discount on this title
Hillmann, Frank; Scheuring, Gerd; Brück, Hans-Jürgen (MueTec GmbH, Hans-Bunte-Str. 5, D-80992 Munich, Germany)
New results using the world’s first optical DUV mask CD (critical dimension) metrology system based on water immersion (WI) technology (Vistec LWM500 WI) are presented. In order to improve repeatability and linearity, especially for feature sizes smaller than 300 nm, a new condenser with an increased numerical aperture (NA) was integrated and qualified. Comparative investigations between the previously used 0.55 NA condenser and the new 0.8 NA condenser are shown and the resulting improvements by the high NA condenser are discussed. This report focuses on results obtained on ArF half tone phase shift masks which are more critical than KrF half tone or binary masks due to the mismatch between measurement and exposure wavelengths.