Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. In 1983, SOPRA has developed the first commercial spectroscopic ellipsometers for research and development. Since this date, the wavelength range has been extended from visible to near infrared (2micrometers ) and far infrared up to 18micrometers . For 193nm micro-lithography, deep UV option down to 190nm has also been developed and delivered more recently. Instrumentation for the next generation of VUV lithography at 157nm requires special optical setup since O₂ and H₂O are extremely absorbing below 190nm. A new system has been developed which works into a purged glove box to reduce the oxygen and water contamination in the part per million range. The optical setup includes a premonochromator in the polarizer arm to avoid photobleaching. The wavelength range of the instrument is 140-700nm. The system works in rotating analyzer configuration to minimize the parasitic residual polarization. Ellipsometric and photometric measurements versus wavelength and angle of incidence can be performed. Scatterometric measurements can also be made. In this wavelength range, the samples are extremely sensitive to any surface contamination and surface roughness. It is why a grazing x-ray option has been added on the same instrument to provide a better picture of the analyzed samples. This paper presents in details the new system with its two measurement methods, and including experimental results on resist, antireflective coatings and gate dielectrics for use in the field of micro-lithography.

Date Published: 20 August 2001
PDF: 11 pages
Proc. SPIE 4343, Emerging Lithographic Technologies V, (20 August 2001); doi: 10.1117/12.436635

Published in SPIE Proceedings Vol. 4343:
Emerging Lithographic Technologies V
Elizabeth A. Dobisz, Editor(s)