13.5 nm High Harmonic Generation Driven by a Visible Noncollinear Optical Parametric Amplifier.

摘要

EUV lithography, using 13.5-nm light, is considered to be the preferred technology for next generation microelectronic circuit fabrication. The introduction of EUV Lithography was delayed already several times and is in danger to be delayed again due to the lack of a high enough power light source allowing for volume production. In this work we investigate whether High Harmonic Generation can be used for such a light source. We build a high energy tunable visible Optical Parametric Amplifier, and drive High Harmonic Generation in Argon and Helium. We study how the efficiency, and the highest producible photon energy, depend on the driver wavelength. We are able to observe EUV light up to the desired wavelength of 13.5 nm. The results agree well with a previously developed theoretical model. We predict that using a 630- nm driver in Helium could have a conversion efficiency of about 10-5. Unfortunately, our pulse energy was too low to confirm this experimentally. This efficiency is too low to construct a EUV source useful for lithography. However, further investigations such as the use of cavity enhancement are necessary to ultimately decide, whether HHG is a viable path to an efficient EUV source.