  In the past years, EUV lithography scanner systems have entered High-Volume
Manufacturing for state-of-the-art Integrated Circuits (IC), with critical
dimensions down to 10 nm. This technology uses 13.5 nm EUV radiation, which is
shaped and transmitted through a near-vacuum H2 background gas. This gas is
excited into a low-density H2 plasma by the EUV radiation, as generated in
pulsed mode operation by the Laser-Produced Plasma (LPP) in the EUV Source.
Thus, in the confinement created by the walls and mirrors within the scanner
system, a reductive plasma environment is created that must be understood in
detail to maximize mirror transmission over lifetime and to minimize molecular
and particle contamination in the scanner. Besides the irradiated mirrors,
reticle and wafer, also the plasma and radical load to the surrounding
construction materials must be considered. This paper will provide an overview
of the EUV-induced plasma in scanner context. Special attention will be given
to the plasma parameters in a confined geometry, such as may be found in the
scanner area near the reticle. Also, the translation of these specific plasma
parameters to off-line setups will be discussed.
