Automated metrology system including VUV spectroscopic ellipsometry and X-ray reflectometry for 300 mm silicon microelectronics

摘要

Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. Instrumentation for the next generation of VUV lithography at 157 nm requires special optical setup since O_2 and H_2O are extremely absorbing below 190 nm. 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 ranges. The optical setup includes a premonochromator in the polarizer arm to avoid photobleaching of organic materials. The wavelength range of the instrument is 140-720 nm. Ellipsometric and photometric measurements vs. wavelength and angle of incidence can be performed. 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. The new system with its two measurement methods is detailed, experimental results on antireflective coatings and high k dielectrics are presented.