A deep UV (DUV) microscope equipped with a 193 nm laser source and a high numerical aperture objective (0.9 NA) is currently developed at the Physikalisch-Technische Bundesanstalt (PTB). The system is designed mainly for traceable critical dimension (CD) metrology on state of the art photomasks up to 6-inch and offers "at-wavelength" measurements for current and future 193 nm lithography. The fundamental mechanical system of the DUV microscope has been carefully designed on the basis of finite element analysis, ensuring the microscope to have a 3D stability in the nanometer range. The comprehensive illumination and imaging system of the 193 nm DUV microscope offers four types of functionality: classical transmission microscopy, polarising microscopy, transmission microscopy with structured aperture illumination and structured field illumination. Together with a well-developed CD modelling approach, the 193 nm DUV microscope will have the capability to determine the CD values of micro- and nanostructures with an uncertainty level of < 10 nm for high quality structures. The status of the 193 nm DUV CD metrology tool is detailed in this publication, and an outlook on future measurement extensions will be presented.

Date Published: 15 May 2010
PDF: 9 pages
Proc. SPIE 7545, 26th European Mask and Lithography Conference, 75450A (15 May 2010); doi: 10.1117/12.863627

Published in SPIE Proceedings Vol. 7545:
26th European Mask and Lithography Conference
Uwe F.W. Behringer; Wilhelm Maurer, Editor(s)