Infineon Installs EUV Exposure System
The tool has been jointly developed with AIXUV - a spin-off of the Fraunhofer Institute for Lasertechnology - and is based on AIXUV's compact EUV-discharge lamp. This lamp generates a plasma in a patented gas discharge geometry (hollow cathode triggered pinch plasma).
EUV radiation is emitted in the spectral range of 9-20nm in pulses of about 30ns. The typical source size is approximately 500micron in diameter and a few mm in length. This is accomplished by heating the working gas (e.g. xenon, air, oxygen, fluorine, etc.) with a current of about 10,000A to temperatures of about 20-30eV (200,000 - 300,000K). The EUV-source has an uptime of 100,000,000 pulses (i.e. more than 500hours at 50Hz).
Material and process related issues to be investigated with such a laboratory exposure tool include resist sensitivity and contrast, surface and line-edge roughness and resist behaviour at high doses such as unwanted outgassing or crosslinking.
AIXUV's open-frame exposer allows exposing of 20 fields of 5mm diameter with individual doses of EUV radiation. Spectral filtering by means of window transmission and multilayer reflection guarantees that only "in-band" EUV-radiation contributes to exposure. Homogeneity of exposures is better than 5% RMS. Typical exposure rates are around 0.1mJ/cm2/minute with the lowest power EUV-lamps.