Illinois debris-mitigation EUV applications laboratory

Gaseous discharge light sources are leading candidates for generating 13.5 nm wavelengths needed for next-generation optical lithography. Electrode debris reaching the first collector optic is a serious concern for device lifetime and cost of ownership. This paper describes the experimental setup and initial data obtained for testing secondary-plasma-based debris mitigation for EUV gas discharge light sources. Operation of a dense plasma focus, secondary RF debris mitigation system, and several in situ diagnostics were successfully tested, achieving first measurements for debris attenuation. It was also found that fast ion and fast neutral particle erosion processes at the optical mirror location dominate over deposition of sputtered metal if a collimator or "foil trap" is positioned between the hot pinch plasma and the first collector optic.